为了更好地了解Na+和K+的动态变化,使用非损伤微测技术(NMT)来监测转基因和WT水稻根尖的Na+和K+流速。100 mM NaCl处理1 h后,所有测试的幼苗均显示出Na+外排。Na+在转基因水稻中的外排速率远高于WT(图1a)。同时,转基因水稻幼苗显示出K+内流,野生稻幼苗显示出K+外排(图1b)。因此,TaPUB15-D在水稻中的过表达明显增加了在盐胁迫下保K+和排Na+的能力。较低的Na+/K+比值确保转基因植株在高盐度条件下具有更好的耐盐性。
其他实验结果
3个TaPUB15同源基因均高度保守。TaPUB15-D定位在细胞核和细胞质中。TaPUB15在幼苗根系表达量最高,其次是幼苗叶片、抽穗期根系和萌发期和幼苗期的根基部。在抽穗的节、茎和旗叶中表达量最低。在250 mM NaCl、50 μM ABA和4°C低温处理下,TaPUB15被强烈激活,但在16.1% PEG处理下TaPUB15被激活程度较低。TaPUB15-D过表达导致转基因水稻的根更长、更多。TaPUB15-D在水稻中的过表达增强了其耐盐性。转基因株系中OsP5CS1的转录水平与WT相比增加了近4倍。钾转运基因OsHKT1;1的表达被盐胁迫显著诱导。TaPUB15-D的过表达减少了Na+的积累,使水稻转基因株系在盐碱条件下保持相对较低的Na+/K+比值。TaPUB15-D的过表达增强了转基因拟南芥的耐盐性。
在对照条件下,野生型和cyp86a1突变体的根中有净Na+内流,但在50 mM NaCl处理下,净Na+流速转为外排(图1a-b)。当用50 mM NaCl处理时,cyp86a1突变体根中的净Na+外排比野生型根中的Na+外排显着降低了38.5%(图1b)。没有NaCl处理时,野生型和cyp86a1均存在净K+内流,尽管cyp86a1根中的K+内流速率比野生型低(图1c-d)。NaCl处理在野生型和cyp86a1根中均引起K+外排,但加入50 mM NaCl后,cyp86a1根中的净K+外排量比野生型中的K+外排量高1.96倍(图1c-d)。
标题:The SNARE protein LbSYP61 participates in salt secretion in Limonium bicolor
作者:山东师范大学戎均康、王宝山、陈敏、Chaoxia Lu
检测离子/分子指标
Na+
检测样品
二色补血草第六个叶片
中文摘要(谷歌机翻)
土壤盐渍化是一个全球性问题,抑制了植物的生长并限制了作物的产量。盐生植物通过盐腺分泌过量的盐,从而避免了盐在其细胞内的过度积累,并保护了自己免受盐相关损害的伤害。但是,尚不清楚通过盐腺分泌盐的分子机制。在这里,我们使用布雷菲德菌素A(BFA),一种高尔基体介导的细胞分泌的特异性抑制剂,通过叶盘法和非侵入式测微法检测双色网状嗜盐菌柠檬酸中囊泡运输是否参与盐的分泌。实际上,在200μg/ ml BFA处理后,盐腺中的盐分泌被显着抑制,盐腺中的高尔基体被破坏,酸性磷酸酶活性被显着抑制。为了进一步检查囊泡运输在盐分泌中的作用,我们使用病毒诱导的基因沉默(VIGS)下调编码反式高尔基体定位的可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体(SNARE)蛋白LbSYP61的基因。使LbSYP61沉默后,双色乳杆菌通过盐腺分泌盐的能力也显着降低。这些结果提供了直接的证据,表明水泡运输通过盐腺参与了盐的分泌,而水泡运输相关蛋白LbSYP61在此过程中起着重要作用。
离子/分子流实验处理方法
Control: 霍格兰营养液培养28 d (0 mM NaCl)
NaCl: 200 mM NaCl
NaCl + DMSO(二甲基亚砜): 200 mMNaCl + 4% DMSO
NaCl + BFA(布雷菲德菌素): 200 mM NaCl +200 μg/ml BFA
NaCl – BFA: NaCl + BFA-treated samples transferred to 200 mM NaCl without BFA
离子/分子流结果
为了进一步证实200μg/mL BFA能显著抑制盐腺的分泌活性,采用NMT技术直接测定了二色补血草叶表皮单个盐腺的Na+分泌速率。在用200mM NaCl处理的叶片后,单个盐腺体的Na+分泌速率增加到对照的28.5倍左右。4% DMSO处理对Na+分泌率无影响,但添加BFA使Na+分泌速率仅为200mM NaCl溶液处理的5.8%。将经BFA处理的叶子转移至不含BFA的200 mM NaCl中,Na+分泌率显著增加,达到200mM NaCl处理的44.7%。因此,囊泡抑制剂BFA可逆地影响盐腺的盐分泌。
其他实验结果
BFA明显抑制盐分泌。分泌液中酸性磷酸酶活性的丧失进一步表明盐的分泌是通过囊泡转运发生的。BFA引起盐腺细胞器的超微结构改变。LbSYP61在200 mM NaCl处理下相对表达变化最大。 LbSYP61是一种典型的高度保守的Qc-SNARE蛋白。LbSYP61基因敲除导致盐分泌减少。
在用50 mM NaCl处理的根中,低氧导致rbohD突变体根部的净Na+和Cl-吸收瞬时增加(图2)。除了成熟区低氧诱导的Na+吸收外,WT根中没有观察到这种效应(图2B)。WT根中的净Na+内流量也显著低于rbohD突变体(图2B)。在这两个区域中,没有测量到对低氧处理响应的净K+流速的显著变化(图3A,B),并且低氧胁迫的开始引起了两个区域向瞬时净Ca2+流出的转变(图3C,D),两个基因型之间没有显着差异。然而,盐胁迫48h后,WT比rbohD突变体在伸长区有更多的Ca2+内流(图3C)。
中国林科院亚热带林业研究所卓仁英研究员课题组在Environmental and Experimental Botany上发表了一篇文章,题目为“Pathogenesis-related protein PR10 fromSalix matsudanaKoidz exhibits resistance to salt stress intransgenicArabidopsis thaliana”,主要探究PR蛋白在植物耐盐机制中起到的作用。
前期的比较蛋白质组学分析表明:沙柳PR蛋白(SmPR10)较为丰富,经过100 mM NaCl处理后表达上调。本实验以沙柳为材料,克隆并鉴定了SmPR10基因,以验证其在耐盐性中的作用。SmPR10的氨基酸序列与紫苏柳和毛白杨的PR蛋白的序列同源性分别为98%和93%。SmPR10定位在拟南芥原生质体的胞质中,根的转录及蛋白水平较高,且100mM NaCl处理后表达上调。免疫定位分析发现,韧皮部纤维细胞和根木质部中特异性的检测到SmPR10。而且,SmPR10的异质过表达提高了转基因拟南芥的耐盐性,具体表现在根长度、根数量、Na+流速、以及叶绿素含量、MDA含量、电导率等生理参数及SOD和POD酶活性水平。
Fig.3–Flux profiles of Na+, K+and Ca2+in roottip elongation zones of 7-day-oldrice seedlings. (a)Net Na+fluxes under favorable culture. (b) Net Na+fluxes under culture with a 120 mmol·L-1NaCl solution. (c) Net K+fluxes under favorable culture. (d) Net K+fluxes under salt stress.(e) Net Ca2+fluxes under favorable culture. (f) Net Ca2+fluxes under culture with a solution of 120 mmol·L-1 NaCl. Net effluxes areindicated by positive and net influxes by negative values. (g) Mean Na+flux. (g) Mean K+flux. (i) Mean Ca2+flux. WT, wildtype.
然后,我们研究了在褪黑素(Mel)预处理的根中瞬时NaCl处理的K+流速动力学。向容器中添加100 mM NaCl会导致水稻植物的伸长区和成熟根区大量的K+流出(图2a,c)。根区之间的K+流出量显着不同,其中伸长区中的K+流出量比成熟区中的K+流出量高一个数量级。与非褪黑素预处理(Mock)相比,褪黑素预处理显着降低了两个根部区域的盐诱导的K+流出(图2)。未经处理的根,伸长和成熟根区的平均K+流出值分别为1,529和205 nmol m-2s-1,而经过预处理的根,分别为632和78 nmol m-2s-1。所有这些结果表明,褪黑激素能够使水稻根部更好地保留K+,其中主要作用是在伸长区中观察到。
为了评估褪黑素对氧化胁迫下根系反应的影响,测量了10 mM H2O2和羟基自由基(由Cu/A混合物生成)处理前后根伸长区的瞬时K+和Ca2+流速。在伸长区,外源Cu/A(0.3/1mM)诱导大量K+外流(图3b);用褪黑素预处理的根使其减少了近3倍。Mel预处理的根和Mock对照对10mMH2O2处理的反应无显著性差异(图3a)。
ROS引发的K+跨质膜(PM)外流通常伴随着植物根部的Ca2+内流,这种ROS诱导的Ca2+吸收量与小麦和大麦的耐盐性呈负相关。因此,我们测量了PM-Ca2+渗透通道对10mM H2O2和Cu/A的敏感性(图3)。结果反映了K+流速的结果(图5c,d)。两种处理均引起根伸长区瞬时净Ca2+吸收。褪黑素预处理已使根Ca2+渗透性离子通道对羟基自由基显着脱敏(Cu / A处理;图3d),而对10 mM H2O2处理的反应没有显著差异(图3c)。
我们进一步表明,在盐碱条件下,Ca2 +结合到ZmNSA1的EF-手结构域,然后通过26S蛋白酶体触发其降解,这反过来又增加了PM-H + -ATPases(MHA2和MHA4)的转录水平。增强SOS1 Na + / H +反转运蛋白介导的根Na +外排。
我们的研究揭示了Ca2 +触发的盐碱耐受性的机制,并为选育耐盐碱玉米品种提供了重要的基因靶标。
英文摘要
Sodium (Na+) toxicityis one of the major damages imposed on crops by saline-alkaline stress.
Here we show thatnatural maize inbred lines display substantial variations in shoot Na+ contentsand saline-alkaline (NaHCO3) tolerance, and reveal that ZmNSA1 (Na+ Contentunder Saline-Alkaline Condition) confers shoot Na+ variations under NaHCO3condition by a genome-wide association study. Lacking of ZmNSA1 promotes shootNa+ homeostasis by increasing root Na+ efflux. A naturally occurred 4-bpdeletion decreases the translation efficiency of ZmNSA1 mRNA, thus promotes Na+homeostasis.
We further show that,under saline-alkaline condition, Ca2+ binds to the EF-hand domain of ZmNSA1then triggers its degradation via 26S proteasome, which in turn increases thetranscripts levels of PM-H+-ATPases (MHA2 and MHA4), and consequently enhancesSOS1 Na+/H+ antiportermediated root Na+ efflux.
Our studies reveal themechanism of Ca2+-triggered saline-alkaline tolerance and provide an importantgene target for breeding saline-alkaline tolerant maize varieties.
标题:Arabidopsis transcription factor WRKY8 functions antagonistically with its interacting partner VQ9 to modulate salinity stress tolerance
影响因子:6.582
检测指标:K+流速
作者:中科院西双版纳热带植物园余迪求、胡彦如
英文摘要
The WRKY transcription factors have been demonstrated to play crucial roles in regulating stress responses; however, the exact mechanisms underlying their involvement in stress responses are not fully understood.
Arabidopsis WRKY8 was predominantly expressed in roots and was highly upregulated by salt treatment. Disruption of WRKY8 rendered plants hypersensitive to salt, showing delayed germination, inhibited post‐germination development and accelerated chlorosis. Further investigation revealed that WRKY8 interacted with VQ9, and their interaction decreased the DNA‐binding activity of WRKY8.
The VQ9 protein was exclusively localized in the nucleus, and VQ9 expression was strongly responsive to NaCl treatment. Mutation of VQ9 enhanced tolerance to salt stress, indicating that VQ9 acts antagonistically with WRKY8 to mediate responses to salt stress. The antagonist functions of WRKY8 and VQ9 were consistent with an increased or reduced Na+/K+ concentration ratio, as well as contrasting expression patterns of downstream stress‐responsive genes in salt‐stressed wrky8 and vq9 mutants.
Moreover, chromatin immunoprecipitation (ChIP) assays showed that WRKY8 directly bound the promoter of RD29A under salt conditions. These results provided strong evidence that the VQ9 protein acts as a repressor of the WRKY8 factor to maintain an appropriate balance of WRKY8‐mediated signaling pathways to establish salinity stress tolerance.
标题:Progress in Understanding the Physiological and Molecular Responses of Populus to Salt Stress
影响因子:4.183
作者:广西农科院、中科院昆明植物所
英文摘要
Salt stress (SS) has become an important factor limiting afforestation programs. Because of their salt tolerance and fully sequenced genomes, poplars (Populus spp.) are used as model species to study SS mechanisms in trees. Here, we review recent insights into the physiological and molecular responses of Populus to SS, including ion homeostasis and signaling pathways, such as the salt overly sensitive (SOS) and reactive oxygen species (ROS) pathways. We summarize the genes that can be targeted for the genetic improvement of salt tolerance and propose future research areas.
标题:Potassium Transporter LrKUP8 Is Essential for K+ Preservation in Lycium ruthenicum, A Salt-Resistant Desert Shrub
影响因子:3.331
检测指标:K+流速
检测样品:黒枸杞愈伤组织
K+流实验处理方法:
有/无300 mM NaCl培养12h
K+流实验测试液成份: 0.5 mM KCl, 0.5 mM NaCl, 0.1mM MgCl2, 0.2 mM CaCl2, 2.5% sucrose,pH 5.7
作者:北京林业大学陈金焕、戴逢斌
英文摘要
Salt stress is a major constraint for many crops and trees. A wild species of Goji named Lycium ruthenicum is an important economic halophyte in China and has an extremely high tolerance to salinity. L. ruthenicum grows in saline soil and is known as a potash-rich species.
However, its salt adaptation strategies and ion balance mechanism remains poorly understood. Potassium (K+) is one of the essential macronutrients for plant growth and development. In this study, a putative salt stress-responsive gene encoding a HAK (high-affinity K+)/KUP (K+ uptake)/KT (K+ transporter) transporter was cloned and designated as LrKUP8.
This gene belongs to the cluster II group of the KT/HAK/KUP family. The expression of LrKUP8 was strongly induced under high NaCl concentrations. The OE-LrKUP8 calli grew significantly better than the vector control calli under salt stress conditions. Further estimation by ion content and micro-electrode ion flux indicated a relative weaker K+ efflux in the OE-LrKUP8 calli than in the control.
Thus, a key gene involved in K+ uptake under salt condition was functionally characterized using a newly established L. ruthenicum callus transformation system. The importance of K+ regulation in L. ruthenicum under salt tolerance was highlighted.
Plants have evolved complex mechanisms that allow them to withstand multiple environmental stresses, including biotic and abiotic stresses.
Here, we investigated the interaction between herbivore exposure and salt stress of Ammopiptanthus nanus, a desert shrub. We found that jasmonic acid (JA) was involved in plant responses to both herbivore attack and salt stress, leading to an increased NaCl stress tolerance for herbivore-pretreated plants, and increase in K+/Na+ ratio in roots. Further evidence revealed the mechanism by which herbivore improved plant NaCl tolerance. Herbivore pretreatment reduced K+ efflux and increased Na+ efflux in plants subjected to long-term, short-term, or transient NaCl stress.
Moreover, herbivore pretreatment promoted H+ efflux by increasing plasma membrane H+-ATPase activity. This H+ efflux creates a transmembrane proton motive force that drives the Na+/H+ antiporter to expel excess Na+ into the external medium. In addition, high cytosolic Ca2+ was observed in the roots of herbivore-treated plants exposed to NaCl, and this effect may be regulated by H+-ATPase.
Taken together, herbivore exposure enhances A. nanus tolerance to salt stress by activating the JA signalling pathway, increasing plasma membrane H+-ATPase activity, promoting cytosolic Ca2+ accumulation, and then restricting K+ leakage and reducing Na+ accumulation in the cytosol.
2011年11月25日,山东省农科院董合忠、孔祥强利用NMT在Journal of Experimental Botany 上发表了标题为Effects of non-uniform root zone salinity on water use Na+ recirculation, and Na+ and H+ flux in cotton的研究成果。
期刊:Journal of Experimental Botany
主题:根系不均一盐胁迫提升植物水分利用率的机制
标题:Effects of non-uniform root zone salinity on water use Na+ recirculation, and Na+ and H+ flux in cotton
影响因子:4.818
检测指标:Na+、H+流速
作者:山东省农科院董合忠、孔祥强
英文摘要
A new split-root system was established through grafting to study cotton response to non-uniform salinity. Each root half was treated with either uniform (100/100 mM) or non-uniform NaCl concentrations (0/200 and 50/150 mM).
In contrast to uniform control, non-uniform salinity treatment improved plant growth and water use, with more water absorbed from the non- and low salinity side. Non-uniform treatments decreased Na+ concentrations in leaves. The [Na+] in the ‘0’ side roots of the 0/200 treatment was significantly higher than that in either side of the 0/0 control, but greatly decreased when the ‘0’ side phloem was girdled, suggesting that the increased [Na+] in the ‘0’ side roots was possibly due to transportation of foliar Na+ to roots through phloem.
Plants under non-uniform salinity extruded more Na+ from the root than those under uniform salinity. Root Na+ efflux in the low salinity side was greatly enhanced by the higher salinity side. NaCl-induced Na+ efflux and H+ influx were inhibited by amiloride and sodium orthovanadate, suggesting that root Na+ extrusion was probably due to active Na+/H+ antiport across the plasma membrane.
Improved plant growth under non-uniform salinity was thus attributed to increased water use, reduced leaf Na+ concentration, transport of excessive foliar Na+ to the low salinity side, and enhanced Na+ efflux from the low salinity root.
2017年11月18日,三峡大学何正权、中国林业科学研究院亚热带林业研究所邱文利用NMT在Environmental and Experimental Botany 上发表了标题为Overexpression of cysteine protease gene from Salix matsudana enhances salt tolerance in transgenic Arabidopsis的研究成果。
期刊:Environmental and Experimental Botany
主题:松柳半胱氨酸蛋白酶基因的过表达增强了转基因拟南芥的耐盐性
标题:Overexpression of cysteine protease gene from Salix matsudana enhances salt tolerance in transgenic Arabidopsis
影响因子:4.369
检测指标:Na+、H+流速
作者:三峡大学何正权、中国林业科学研究院亚热带林业研究所邱文
英文摘要
Salix matsudana is a salt-tolerant arbor tree species. We are interested in understanding its mechanisms of salt-tolerance.
Here, we isolated a full-length 1080-bp cDNA for a salt stress-responsive cysteine protease gene from S. matsudana, designated SmCP. The deduced 359-amino-acid SmCP protein was essentially identical to cysteine proteases of other plant species and was predicted to contain inhibitor-I29 and peptidase-C1A domains with three active catalytic sites found in eukaryotic cysteine proteases.
Expression profile analysis revealed that SmCP expression is constitutive and overexpression in roots takes place under salt stress. Expression of SmCP in Escherichia coli cells led to enhanced salinity tolerance. In addition, transgenic Arabidopsis thaliana lines overexpressing SmCP displayed enhanced tolerance to salt stress, with increased germination rates, antioxidant enzyme (superoxide dismutase) activity, chlorophyll content and ion flux in the root, and reduced malondialdehyde (MDA) levels and electric conductivity compared with control plants.
These results indicate that SmCP likely plays an important role in salt tolerance in S. matsudana.
中文摘要(谷歌机翻)
柳柳是耐盐的乔木树种。我们有兴趣了解其耐盐性机制。
在这里,我们从S. matsudana,命名为SmCP的盐胁迫响应半胱氨酸蛋白酶基因中分离出全长1080 bp cDNA。推导的359个氨基酸的SmCP蛋白与其他植物物种的半胱氨酸蛋白酶基本相同,并且预计包含在真核半胱氨酸蛋白酶中具有三个活性催化位点的抑制剂I29和肽酶C1A域。
2012年11月02日,河北师范大学崔素娟、王鹏利用NMT在Journal of Biological Chemistry 上发表了标题为A Na+ Ca2+ exchanger-like protein (AtNCL) involved in salt stress in Arabidopsis 的研究成果。
2016年11月02日,浙江大学李廷强、陶琦利用NMT在Journal of Experimental Botany 上发表了标题为The apoplasmic pathway via the root apex and lateral roots contributes to Cd hyperaccumulation in the hyperaccumulator Sedum alfredii的研究成果。
期刊:Journal of Biological Chemistry
主题:Na+ Ca2+交换蛋白样蛋白(AtNCL)参与拟南芥的盐胁迫
标题:A Na+ Ca2+ exchanger-like protein (AtNCL) involved in salt stress in Arabidopsis
影响因子:4.773
检测指标:Ca2+流速
作者:河北师范大学崔素娟、王鹏
英文摘要
Calcium ions (Ca2+) play a crucial role in many key physiological processes; thus, the maintenance of Ca2+ homeostasis is of primary importance. Na+/Ca2+ exchangers (NCXs) play an important role in Ca2+ homeostasis in animal excitable cells.
Bioinformatic analysis of the Arabidopsis genome suggested the existence of a putative NCX gene, Arabidopsis NCX-like (AtNCL), encoding a protein with an NCX-like structure and different from Ca2+/H+ exchangers and Na+/H+ exchangers previously identified in plant. AtNCL was identified to localize in the Arabidopsis cell membrane fraction, have the ability of binding Ca2+, and possess NCX-like activity in a heterologous expression system of cultured mammalian CHO-K1 cells. AtNCL is broadly expressed in Arabidopsis, and abiotic stresses stimulated its transcript expression.
Loss-of-function atncl mutants were less sensitive to salt stress than wild-type or AtNCL transgenic overexpression lines. In addition, the total calcium content in whole atncl mutant seedlings was higher than that in wild type by atomic absorption spectroscopy. The level of free Ca2+ in the cytosol and Ca2+ flux at the root tips of atncl mutant plants, as detected using transgenic aequorin and a scanning ion-selective electrode, required a longer recovery time following NaCl stress compared with that in wild type.
All of these data suggest that AtNCL encodes a Na+/Ca2+ exchanger-like protein that participates in the maintenance of Ca2+ homeostasis in Arabidopsis. AtNCL may represent a new type of Ca2+ transporter in higher plants.
标题:The apoplasmic pathway via the root apex and lateral roots contributes to Cd hyperaccumulation in the hyperaccumulator Sedum alfredii
影响因子:5.354
检测指标:Cd2+流速
作者:浙江大学李廷强、陶琦
英文摘要
Although the significance of apoplasmic barriers in roots with regards to the uptake of toxic elements is generally known, the contribution of apoplasmic bypasses (ABs) to cadmium (Cd) hyperaccumulation is little understood.
Here, we employed a combination of stable isotopic tracer techniques, an ABs tracer, hydraulic measurements, suberin lamellae staining, metabolic inhibitors, and antitranspirants to investigate and quantify the impact of the ABs on translocation of Cd to the xylem in roots of a hyperaccumulating (H) ecotype and a non-hyperaccumulating (NH) ecotype of Sedum alfredii.
In the H ecotype, the Cd content in the xylem sap was proportional to hydrostatic pressure, which was attributed to pressure-driven flow via the ABs. The contribution of the ABs to Cd transportation to the xylem was dependent on the Cd concentration applied to the H ecotype (up to 37% at the highest concentration used). Cd-treated H ecotype roots showed significantly higher hydraulic conductance compared with the NH ecotype (76 vs 52 × 10–8 m s–1MPa–1), which is in accordance with less extensive suberization due to reduced expression of suberin-related genes.
The main entry sites of apoplasmically transported Cd were localized in the root apexes and lateral roots of the H ecotype, where suberin lamellae were not well developed. These findings highlight the significance of the apoplasmic bypass in Cd hyperaccumulation in hyperaccumulating ecotypes of S. alfredii.
在H型生态系统中,木质部汁液中的Cd含量与静水压力成正比,这归因于通过AB的压力驱动流。 AB对Cd向木质部运输的贡献取决于应用于H生态型的Cd浓度(使用最高浓度时高达37%)。与NH生态型相比,Cd处理的H生态型根系显示出更高的水力传导性(76 vs 52×10–8 m s–1MPa-1),这与由于suberin相关基因表达减少而引起的泛化作用减弱有关。
标题:Root-zone-specific sensitivity of K+-and Ca2+-permeable channels to H2O2 determines ion homeostasis in salinized diploid and hexaploid Ipomoea trifida
K+、H+、Ca2+、Na+流速流实验测试液成份: H+/K+/Ca2+瞬时:0.1 mM NaCl, 0.1 mM MgCl2,0.1 mM CaCl2, and 0.5 mM KCl at pH 5.7 K+:150 mM NaCl, 0.1 mM MgCl2, 0.1 mM CaCl2, and 0.5 mM KCl, pH 5.7
作者:江苏师范大学孙健、李宗芸
英文摘要
Polyploids generally possess superior K+/Na+ homeostasis under saline conditions compared with their diploid progenitors.
In this study, we identified the physiological mechanisms involved in the ploidy-related mediation of K+/Na+ homeostasis in the roots of diploid (2x) and hexaploid (6x; autohexaploid) Ipomoea trifida, which is the closest relative of cultivated sweet potato. Results showed that 6x I. trifida retained more K+ and accumulated less Na+ in the root and leaf tissues under salt stress than 2x I. trifida.
Compared with its 2x ancestor, 6x I. trifida efficiently prevents K+ efflux from the meristem root zone under salt stress through its plasma membrane (PM) K+-permeable channels, which have low sensitivity to H2O2. Moreover, 6x I. trifida efficiently excludes Na+ from the elongation and mature root zones under salt stress because of the high sensitivity of PM Ca2+-permeable channels to H2O2.
Our results suggest the root-zone-specific sensitivity to H2O2 of PM K+- and Ca2+-permeable channels in the co-ordinated control of K+/Na+ homeostasis in salinized 2x and 6x I. trifida. This work provides new insights into the improved maintenance of K+/Na+ homeostasis of polyploids under salt stress.
中文摘要(谷歌机翻)
与二倍体祖细胞相比,多倍体在盐水条件下通常具有优越的K+ / Na+稳态。
在这项研究中,我们确定了与二倍体(2x)和六倍体(6x;自六倍体)Tripoda的根的K+/ Na+稳态的倍性相关介导有关的生理机制,这是栽培红薯的近亲。结果表明,与2x I. trifida相比,在盐胁迫下6x I. trifida保留更多的K +并在根和叶组织中积累较少的Na+。
与2x祖先相比,6x裂叶线虫通过其对H2O2敏感性低的质膜(PM)K+渗透通道有效地防止了盐胁迫下分生组织根区的K+流出。此外,由于PM Ca2+的可渗透通道对H2O2的敏感性高,因此6x I. trifida有效地将Na+从盐胁迫下的伸长和成熟根区中排除。
NO3-流速流实验测试液成份: NO3- measuring solution: 0.1 mM KNO3, 0.1 mM KCl, 0.1 mM CaCl2, pH 5.3 was adjusted with KOH and HCl. H+ measuring solution: 0.1 mM NaCl, 0.1 mM MgCl2, 0.1 mM CaCl2 and 0.5 mM KCl, pH 5.3 was adjusted with KOH and HCl.
作者:北京林业大学陈少良、撒刚、邓晨
英文摘要
Salt stress is an important environmental cue impeding poplar nitrogen nutrition. Here, we characterized the impact of salinity on proton‐driven nitrate fluxes in ectomycorrhizal roots and the importance of a Hartig net for nitrate uptake.
We employed two Paxillus involutus strains for root colonization: MAJ, which forms typical ectomycorrhizal structures (mantle and Hartig net), and NAU, colonizing roots with a thin, loose hyphal sheath. Fungus‐colonized and noncolonized Populus × canescens were exposed to sodium chloride and used to measure root surface pH, nitrate (NO3−) flux and transcription of NO3− transporters (NRTs; PcNRT1.1, ‐1.2, ‐2.1), and plasmalemma proton ATPases (HAs; PcHA4, ‐8, ‐11).
Paxillus colonization enhanced root NO3− uptake, decreased surface pH, and stimulated NRTs and HA4 of the host regardless the presence or absence of a Hartig net. Under salt stress, noncolonized roots exhibited strong net NO3− efflux, whereas beneficial effects of fungal colonization on surface pH and HAs prevented NO3− loss. Inhibition of HAs abolished NO3− influx under all conditions.
We found that stimulation of HAs was crucial for the beneficial influence of ectomycorrhiza on NO3− uptake, whereas the presence of a Hartig net was not required for improved NO3− translocation. Mycorrhizas may contribute to host adaptation to salt‐affected environments by keeping up NO3− nutrition.
2012年9月21日,中科院南京土壤研究所施卫明、张建华、许卫锋利用NMT在Journal of Experimental Botany上发表了标题为PIN2 is required for the adaptation of Arabidopsis roots to alkaline stress by modulating proton secretion的研究成果。
期刊:Journal of Experimental Botany
主题:PIN2调节碱胁迫下质子分泌
标题:PIN2 is required for the adaptation of Arabidopsis roots to alkaline stress by modulating proton secretion
Soil alkalinity is a widespread environmental problem that limits agricultural productivity. The hypothesis that an auxin-regulated proton secretion by plasma membrane H+-ATPase plays an important role in root adaption to alkaline stress was studied. It was found that alkaline stress increased auxin transport and PIN2 (an auxin efflux transporter) abundance in the root tip of wild-type Arabidopsis plants (WT).
Compared with WT roots, the pin2 mutant roots exhibited much reduced plasma membrane H+-ATPase activity, root elongation, auxin transport, and proton secretion under alkaline stress. More importantly, roots of the pks5 mutant (PKS5, a protein kinase) lacking PIN2 (a pks5/pin2 double mutant) lost the previous higher proton-secretion capacity and higher elongation rate of primary roots under alkaline stress.
By using Arabidopsis natural accessions with a high proton-secretion capacity, it was found that their PIN2 transcription abundance is positively related to the elongation rate of the primary root and proton-secretion capacity under alkaline stress.
Taken together, our results confirm that PIN2 is involved in the PKS5-mediated signalling cascade under alkaline-stress and suggest that PIN2 is required for the adaptation of roots to alkaline stress by modulating proton secretion in the root tip to maintain primary root elongation.
2018年9月19日,北京林业大学陈少良、林善枝、赵楠、孙健利用NMT在Frontiers in Plant Science上发表了标题为Hydrogen Sulfide Mediates K+ and Na+ Homeostasis in the Roots of Salt-Resistant and Salt-Sensitive Poplar Species Subjected to NaCl Stress的研究成果。
期刊:Frontiers in Plant Science
主题:硫化氢介导盐胁迫和盐敏感杨树种根系中的K+和Na+稳态
标题:Hydrogen Sulfide Mediates K+ and Na+ Homeostasis in the Roots of Salt-Resistant and Salt-Sensitive Poplar Species Subjected to NaCl Stress.
0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.2 mM Na2SO4, and 0.3 mM MES, pH 4.0
作者:北京林业大学陈少良、林善枝、赵楠、孙健
英文摘要
Non-invasive micro-test techniques (NMT) were used to analyze NaCl-altered flux profiles of K+, Na+, and H+ in roots and effects of NaHS (a H2S donor) on root ion fluxes in two contrasting poplar species, Populus euphratica (salt-resistant) and Populus popularis (salt-sensitive).
Both poplar species displayed a net K+ efflux after exposure to salt shock (100 mM NaCl), as well as after short-term (24 h), and long-term (LT) (5 days) saline treatment (50 mM NaCl, referred to as salt stress). NaHS (50 μM) restricted NaCl-induced K+ efflux in roots irrespective of the duration of salt exposure, but K+ efflux was not pronounced in data collected from the LT salt stress treatment of P. euphratica.
The NaCl-induced K+ efflux was inhibited by a K+ channel blocker, tetraethylammonium chloride (TEA) in P. popularis root samples, but K+ loss increased with a specific inhibitor of plasma membrane (PM) H+-ATPase, sodium orthovanadate, in both poplar species under LT salt stress and NaHS treatment. This indicates that NaCl-induced K+ loss was through depolarization-activated K+ channels. NaHS caused increased Na+ efflux and a corresponding increase in H+ influx for poplar roots subjected to both the short- and LT salt stress.
The NaHS-enhanced H+ influx was not significant in P. euphratica samples subjected to short term salt stress. Both sodium orthovanadate and amiloride (a Na+/H+ antiporter inhibitor) effectively inhibited the NaHS-augmented Na+ efflux, indicating that the H2S-enhanced Na+ efflux was due to active Na+ exclusion across the PM. We therefore conclude that the beneficial effects of H2S probably arise from upward regulation of the Na+/H+ antiport system (H+ pumps and Na+/H+ antiporters), which promote exchange of Na+ with H+ across the PM and simultaneously restricted the channel-mediated K+ loss that activated by membrane depolarization.
NH4+: 0.1 mM NH4NO3, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
NO3-: 0.1 mM NH4NO3, 1.0 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
作者:山东农业大学林学院马风云、刘秀梅
英文摘要
A potted experiment with Populus × euramericana ‘Neva’ was carried out to assess whether there are positive effects of magnetic treatment of saline water (MTSW) on nitrogen metabolism under controlled conditions in a greenhouse.
Growth properties, nitrogen contents, enzyme activities and metabolite concentrations were determined based on field experiments and laboratory analysis after a 30-day treatment.
The results were as follows: (1) Biomass accumulation, root morphological properties and total nitrogen content were improved by MTSW. (2) Magnetization led to a greater increase in nitrate-nitrogen (NO3−-N) content in roots than in leaves, accompanied by greater NO3− efflux and activated nitrate reductase. (3) MTSW led to a higher ammonium-nitrogen (NH4+-N) content and greater uptake of net NH4+ in the leaves than that in the roots. (4) Magnetization stimulated glutamine synthase, glutamate dehydrogenase and glutamate synthase activities, whereas the concentrations of glutathione and oxidized glutathione were increased in leaves but decreased in roots, and the total glutathione content was increased.
Overall, these results indicated some beneficial impacts of MTSW on nitrogen translocation under field conditions, especially for equilibrating the distribution of NO3−-N and NH4+-N. Moreover, these findings confirmed the potential of using low-quality water for agriculture.
2013年8月19日,厦门大学郑海雷、陈娟利用NMT在PLoS ONE上发表了标题为Nitric Oxide Mediates Root K+/Na+ Balance in a Mangrove Plant, Kandelia obovata, by Enhancing the Expression of AKT1-Type K+ Channel and Na+/H+ Antiporter under High Salinity的研究成果。
期刊:PLoS ONE
主题:NO调控红树耐盐机制
标题:Nitric Oxide Mediates Root K+/Na+ Balance in a Mangrove Plant, Kandelia obovata, by Enhancing the Expression of AKT1-Type K+ Channel and Na+/H+ Antiporter under High Salinity
影响因子:3.730
检测指标:Na+,K+流速
检测部位:红树根(距离根尖20mm)
Na+,K+流实验处理方法:
红树幼苗,400mM NaCl/100mM SNP/400mM NaCl+100mM SNP处理15天,100 mM阿米洛利/500 mM钒酸盐/200 mM cPTIO瞬时处理
Na+,K+流实验测试液成份:
0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2,0.5 mM NaCl, 0.2 mM Na2SO4, 0.3 mM MES, pH 6.0
通讯作者:厦门大学郑海雷、陈娟
英文摘要
It is well known that nitric oxide (NO) enhances salt tolerance of glycophytes. However, the effect of NO on modulating ionic balance in halophytes is not very clear. This study focuses on the role of NO in mediating K+/Na+ balance in a mangrove species, Kandelia obovata Sheue, Liu and Yong.
We first analyzed the effects of sodium nitroprusside (SNP), an NO donor, on ion content and ion flux in the roots of K. obovata under high salinity. The results showed that 100 μM SNP significantly increased K+ content and Na+ efflux, but decreased Na+ content and K+ efflux. These effects of NO were reversed by specific NO synthesis inhibitor and scavenger, which confirmed the role of NO in retaining K+ and reducing Na+ in K. obovata roots.
Using western-blot analysis, we found that NO increased the protein expression of plasma membrane (PM) H+-ATPase and vacuolar Na+/H+ antiporter, which were crucial proteins for ionic balance. To further clarify the molecular mechanism of NO-modulated K+/Na+ balance, partial cDNA fragments of inward-rectifying K+ channel, PM Na+/H+ antiporter, PM H+-ATPase, vacuolar Na+/H+ antiporter and vacuolar H+-ATPase subunit c were isolated. Results of quantitative real-time PCR showed that NO increased the relative expression levels of these genes, while this increase was blocked by NO synthesis inhibitors and scavenger.
Above results indicate that NO greatly contribute to K+/Na+ balance in high salinity-treated K. obovata roots, by activating AKT1-type K+ channel and Na+/H+ antiporter, which are the critical components in K+/Na+ transport system.
Effects of NaCl and SNP on K+ and Na+ fluxes in K. obovata roots. After 15 days of exposure to NaCl (400 mM), SNP (100 mM) and NaCl (400 mM)+SNP (100 mM), the net K+ (A) and Na+ (C) fluxes from the mature root zone (20 mm from the tip) of K. obovata seedlings. The positive value in the figures represents the net influx and negative value represents the net efflux. Each point represents the mean value of four individual roots and bars represent the SE of the mean. The mean fluxes of K+ (B) and Na+ (D) within the measuring periods are shown. Columns labeled with different letters indicates significantly different at P,0.05.
2012年8月16日,中国农科院兰州畜牧与兽药研究所王晓力副研究员同兰州大学张金林副教授利用NMT在Plant Science上发表了标题为The coordinated regulation of Na+ and K+ in Hordeum brevisubulatum responding to time of salt stress的研究成果。
期刊:Plant Science
主题:响应盐胁迫时间的大麦Na+和K+的调控
标题:The coordinated regulation of Na+and K+ in Hordeum brevisubulatum responding to time of salt stress
影响因子:3.362
检测指标:Na+,K+流速
检测部位:野大麦根尖部位
Na+,K+流实验处理方法:
四叶期大麦,0/100mM NaCl处理7天,100mM NaCl处理60天
Na+,K+流实验测试液成份:
0.1 mMKCl, 0.1 mM CaC12, 0.1 mM MgC12, 0.5 mM NaCl, 0.2 mM Na2SO4,0.3 mM MES, pH 6.0
通讯作者:中国农科院兰州畜牧与兽药研究所王晓力、兰州大学张金林
英文摘要
Hordeum brevisubulatum, called as wild barley, is a useful monocotyledonous halophyte for soil improvement in northern China. Although previously studied, its main salt tolerance mechanism remained controversial.
The current work showed that shoot Na+ concentration was increased rapidly with stress time and significantly higher than in wheat during 0–168 h of 100 mM NaCl treatment. Similar results were also found under 25 and 50 mM NaCl treatments. Even K+ was increased from 0.01 to 50 mM in the cultural solution, no significant effect was found on tissue Na+ concentrations. Interestingly, shoot growth was improved, and stronger root activity was maintained in H.
brevisubulatum compared with wheat after 7 days treatment of 100 mM NaCl. To investigate the long-term stress impact on tissue Na+, 100 mM NaCl was prolonged to 60 days. The maximum values of Na+ concentrations were observed at 7th in shoot and 14th day in roots, respectively, and then decreased gradually. Micro-electrode ion flux estimation was used and it was found that increasing Na+ efflux while maintaining K+ influx were the major strategies to reduce the Na+ concentration during long-term salt stress. Moreover, leaf Na+ secretions showed little contribution to the tissue Na+ decrease.
Thereby, the physiological mechanism for H. brevisubulatum to survive from long-term salt stress was proposed that rapid Na+ accumulation occurred in the shoot to respond the initial salt shock, then Na+ efflux was triggered and K+ influx was activated to maintain a stable K+/Na+ ratio in tissues.
Fig. 4. Net Na+ flux of H. brevisubulatum test by MIFE between 50 and 390 s in mea-suring solution after 0 and 100 mM NaCl treatment (increased stepwise with 25 mM per 12 h) in modified Hoagland solution for 7 d and 100 mM NaCl for 60 d. Roots (with shoots retained) were incubated in the measuring solution to equilibrate for 15 min in advance. Steady-state ion fluxes were then recorded until the values variation amplitude is relatively stable. Ten plants for H. brevisubulatum were pooled in each replicate (n = 6). Values are means ± SD and bars indicate SD.
2017年8月14日,中央民族大学夏建新、北京林业大学陈少良利用NMT在Frontiers in Plant Science上发表了标题为Salt-Sensitive Signaling Networks in the Mediation of K+/Na+ Homeostasis Gene Expression in Glycyrrhiza uralensis Roots的文章。
期刊:Frontiers in Plant Science
主题:盐敏感信号网络在甘草根中Na+/K+稳态基因表达的调控
标题:Salt-Sensitive Signaling Networks in the Mediation of K+/Na+ Homeostasis Gene Expression in Glycyrrhiza uralensis Roots
两周的甘草幼苗,0/100mM NaCl处理24小时后,促进剂(Ca2+, H2O2, SNP, and ATP)或者抑制剂(阿米洛利,原钒酸钠,TEA,LaCl3,DMTU,cPTIO和PPADs)处理30min
Na+,K+,H+流实验测试液成份:
0.1 mM NaCl, 0.1 mM MgCl2, 0.1 mM CaCl2, and 0.5 mM KCl
通讯作者:中央民族大学夏建新、北京林业大学陈少良
英文摘要
We investigated the effects of salt-sensitive signaling molecules on ionic fluxes and gene expression related to K+/Na+ homeostasis in a perennial herb, Glycyrrhiza uralensis, during short-term NaCl stress (100 mM, 24 h). Salt treatment caused more pronounced Na+ accumulation in root cells than in leaf cells. Na+ ions were mostly compartmentalized in vacuoles. Roots exposed to NaCl showed increased levels of extracellular ATP (eATP), cytosolic Ca2+, H2O2, and NO.
Steady-state flux recordings revealed that these salt-sensitive signaling molecules enhanced NaCl-responsive Na+ efflux, due to the activated Na+/H+ antiport system in the plasma membrane (PM). Moreover, salt-elicited K+ efflux, which was mediated by depolarization-activated cation channels, was reduced with the addition of Ca2+, H2O2, NO, and eATP. The salt-adaptive effects of these molecules (Na+ extrusion and K+ maintenance) were reduced by pharmacological agents, including LaCl3 (a PM Ca2+ channel inhibitor), DMTU (a reactive oxygen species scavenger), cPTIO (an NO scavenger), or PPADS (an antagonist of animal PM purine P2 receptors).
RT-qPCR data showed that the activation of the PM Na+/H+ antiport system in salinized roots most likely resulted from the upregulation of two genes, GuSOS1 and GuAHA, which encoded the PM Na+/H+ antiporter, salt overly sensitive 1 (SOS1), and H+-ATPase, respectively. Clear interactions occurred between these salt-sensitive agonists to accelerate transcription of salt-responsive signaling pathway genes in G. uralensis roots.
For example, Ca2+, H2O2, NO, and eATP promoted transcription of GuSOS3 (salt overly sensitive 3) and/or GuCIPK (CBL-interacting protein kinase) to activate the predominant Ca2+-SOS signaling pathway in salinized liquorice roots. eATP, a novel player in the salt response of G. uralensis, increased the transcription of GuSOS3, GuCIPK, GuRbohD (respiratory burst oxidase homolog protein D), GuNIR (nitrate reductase), GuMAPK3, and GuMAPK6 (the mitogen-activated protein kinases 3 and 6). Moreover, GuMAPK3 and GuMAPK6 expression levels were enhanced by H2O2 in NaCl-stressed G. uralensis roots.
Our results indicated that eATP triggered downstream components and interacted with Ca2+, H2O2, and NO signaling to maintain K+/Na+ homeostasis. We propose that a multiple signaling network regulated K+/Na+ homeostasis in NaCl-stressed G. uralensis roots.
(A) Na+ and (B) K+ were measured along the root axis at the apical zones (200–2700 µm from the root tip) in no-salt (left panels) and salt-stressed (center panels) conditions. Each point represents the mean of five to six individual plants. ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, compared to controls. (Right panels) Means of Na+ and K+ fluxes at all measurement points, in no-salt (–NaCl) and salt-stressed (+NaCl) plants. Bars (±SD) represent the means of five to six individual plants; different letters (a, b, c, and d) indicate significant differences (P < 0.05) between treatments.
The impact of freshwater (FW) salinization on osmoregulation as well as tracheal gill morphology and function was examined in nymphs of the mayfly Hexagenia rigida following exposure to salt contaminated water (SCW, 7.25 g/l NaCl) for a 7-day period.
Ionoregulatory homeostasis was perturbed in SCW exposed H. rigida nymphs as indicated by increased hemolymph Na+, K+ and Cl− levels as well as hemolymph pH and water content. Despite this, SCW did not alter gill Na+-K+-ATPase (NKA) or V-type H+-ATPase (VA) activity. In addition, NKA and VA immunolocalization in gill ionocytes did not show alterations in enzyme location or changes in ionocyte abundance.
The latter observation was confirmed using scanning electron microscopy (SEM) to examine exposed tracheal gill ionocyte numbers. Ionocyte surface morphometrics also revealed that SCW did not change individual ionocyte surface area or ionocyte fractional surface area. Nevertheless, analysis of Na+ movement across the tracheal gill of mayfly nymphs using scanning ion-selective electrode technique indicated that FW nymphs acquired Na+ from surrounding water, while tracheal gills of SCW nymphs had the capacity to secrete Na+.
Because Na+ secretion across the gill of SCW-exposed animals occurred in the absence of any change in (1) NKA and VA activity or (2) ionocyte numbers/surface exposure, it was reasoned that Na+ movement across the gill of SCW animals may be occurring, at least in part, through the paracellular pathway. The ultrastructure of tracheal gill septate junctions (SJs) supported this idea as they exhibited morphological alterations indicative of a leakier pathway. Data provide a first look at alterations in osmoregulatory mechanisms that allow H. rigida nymphs to tolerate sub-lethal salinization of their surroundings.
中文摘要(谷歌机翻)
在暴露于盐污染的水(SCW,7.25g / l NaCl)7天后,在may fly(Hexflynia rigida)的若虫中检查淡水(FW)盐化对渗透调节以及气管鳃形态和功能的影响。
2012年8月9日,河北师范大学黄占景、肖艳红利用NMT在Physiologia Plantarum上发表了标题为A novel wheat α-amylase inhibitor gene, TaHPS, significantly improves the salt and drought tolerance of transgenic Arabidopsis的文章。
期刊:Physiologia Plantarum
主题:一种新型小麦α-淀粉酶抑制剂基因TaHPS显着提高了转基因拟南芥的耐盐性和耐旱性
标题:A novel wheat α-amylase inhibitor gene, TaHPS, significantly improves the salt and drought tolerance of transgenic Arabidopsis
影响因子:3.656
检测指标:Na+、K+、Ca2+流速
检测部位:根、保卫细胞
Na+、K+、Ca2+流实验处理方法:
5天的小麦幼苗,0或200mM NaCl处理1天
Na+、K+、Ca2+流实验测试液成份:文献无
推荐测试液成份:
Na+(根):0.5mM NaCl,pH 6.0
Ca+、K+(保卫细胞):0.1mM CaCl2,0.1mM KCl,pH 6.0
通讯作者:河北师范大学黄占景、肖艳红
英文摘要
On the basis of microarray analyses of the salt‐tolerant wheat mutant RH8706‐49, a previously unreported salt‐induced gene, designated as TaHPS [Triticum aestivum hypothetical (HPS)‐like protein], was cloned.
Real‐time quantitative polymerase chain reaction analyses showed that expression of the gene was induced by abscisic acid, salt and drought. The encoded protein was found to be localized mainly in the plasma membranes. Transgenic Arabidopsis plants overexpressing TaHPS were more tolerant to salt and drought stresses than non‐transgenic wild‐type (WT) plants. Under salt stress, the root cells of the transgenic plants secreted more Na+ and guard cells took up more Ca2+ ions. Compared with wild‐type plants, TaHPS‐expressing transgenic plants showed significantly lower amylase activity and glucose and malic acid levels.
Our results showed that the expression of TaHPS inhibited amylase activity, which subsequently led to a closure of stomatal apertures and thus improved plant tolerance to salt and drought.
Phenotypes of plants treated with NaCl and PEG for three weeks. (A) Treated with 0 mM NaCl for 3 weeks.Non-destructive determination of centrifugal flow and fluxes.(A) Flow and fluxes of Na+ in root cells.
In this study, in order to investigate the role of Ca2+ in GABA signal transduction involved in phenolics accumulation in barley seedlings under NaCl stress, the seedlings were treated with exogenous GABA and its synthesis inhibitor, 3-mercaplopropionic acid (3-MP), as well as Ca2+ channel blockers La3+, Ca2+ chelator EGTA, and Ca2+ release channel inhibitor 2-aminoethoxydiphenyl borate (2-APB).
The results showed that GABA significantly enhanced phenolics, calcium and calmodulin content. It also induced Ca2+ influx in barley root tips cells, and altered the distribution of Ca2+, making calcium precipitates more uniform and intensive. While, 3-MP treatment led to opposite changes, which suggested that GABA was essential for calcium content increase. In addition, accumulation of phenolics was inhibited by LaCl3, EGTA and 2-APB treatments, and this inhibition could be alleviated partly by exogenous GABA.
Taken together, Ca2+ was involved in GABA signal transduction for phenolics accumulation in barley seedlings under NaCl stress.
标题:The involvement of wheat (Triticum aestivum L.) U-box E3 ubiquitin ligase TaPUB1 in salt stress tolerance
影响因子:3.129
检测指标:Na+、K+、H+流速
检测部位:根部分生区
Na+、K+、H+流实验处理方法:
7日龄小麦,200mM NaCl瞬时胁迫处理/200uM NaC处理7天
Na+、K+、H+流实验测试液成份:文献无
推荐测试液成份:
Na+/H+:0.5mM NaCl ,0.3mM MES,pH6.0
K+/H+:0.1mM KCl ,0.3mM MES,pH6.0
通讯作者:山东农业大学王玮、枣庄学院王文强
英文摘要
U‐box E3 ubiquitin ligases play important roles in the ubiquitin/26S proteasome machinery and in abiotic stress responses. TaPUB1‐overexpressing wheat (Triticum aestivum L.) were generated to evaluate its function in salt tolerance. These plants were more salt stress tolerance during seedling and flowering stages, whereas the TaPUB1‐RNAi‐mediated knock‐down transgenic wheat showed more salt stress sensitivity than the wild type (WT).
TaPUB1 overexpression up‐regulated the expression of genes related to ion channels and increased the net root Na+ efflux, but decreased the net K+ efflux and H+ influx, thereby maintaining a low cytosolic Na+/K+ ratio, compared with the WT. However, RNAi‐mediated knock‐down plants showed the opposite response to salt stress. TaPUB1 could induce the expression of some genes that improved the antioxidant capacity of plants under salt stress. TaPUB1 also interacted with TaMP (Triticum aestivum.α‐mannosidase protein), a regulator playing an important role in salt response in yeast and in plants.
Thus, low cytosolic Na+/K+ ratios and better antioxidant enzyme activities could be maintained in wheat with overexpression of TaPUB1 under salt stress. Therefore, we conclude that the U‐box E3 ubiquitin ligase TaPUB1 positively regulates salt stress tolerance in wheat.
与WT相比,TaPUB1过表达上调与离子通道相关的基因的表达并增加净根Na +流出,但降低净K +流出和H +流入,从而维持低细胞溶质Na + / K +比率。然而,RNAi介导的敲低植物显示出对盐胁迫的相反反应。TaPUB1可诱导某些基因的表达,从而提高盐胁迫下植物的抗氧化能力。TaPUB1还与TaMP(Triticumaestivum.α-甘露糖苷酶蛋白)相互作用,TaMPUB是一种在酵母和植物中的盐响应中起重要作用的调节剂。
因此,在盐胁迫下过表达TaPUB1的小麦中可以维持较低的细胞溶质Na + / K +比率和较好的抗氧化酶活性。因此,我们得出结论,U-box E3泛素连接酶TaPUB1正调节小麦的盐胁迫耐受性。
Figure 4. Accumulation of Na+ and K+ in transgenic and WT plants under normal and salt stress conditions (E) The Na+/K+ ratio in the roots of transgenic and WT plants exposed to 0 mM and 200 mM NaCl. (F and G) Quantification of Na+ and K+ content in leaves of transgenic and WT plants without and with 200 mM NaCl treatment. (H) The Na+/K+ ratio in the leaves of transgenic and WT plants exposed to 0 mM and 200 mM NaCl. The data were presented as the mean ±SD of three independent experiments. Asterisks above each column indicate statistical differences to the WT plants (*P<0.05; **P<0.01).
Aquaporins (AQPs) are channel proteins that facilitate water transport across cell membranes and play important roles in many biological processes. However, most AQP functions are still poorly understood in the plant kingdom. Here, MsPIP2;2 was isolated and identified from alfalfa (Medicago sativa). MsPIP2;2 was localized to the plasma membrane, and its expression was induced by salt and abscisic acid (ABA) treatment. Overexpression of MsPIP2;2 in Arabidopsis increased the seed germination rate, seedling root length, survival rate, proline content and antioxidant defence activity and decreased cell membrane damage and reactive oxygen species (ROS) accumulation compared to those in WT under salt stress.
The salt tolerance of MsPIP2;2 was affected by Ca2+ and pH in transgenic Arabidopsis plants. MsPIP2;2-overexpressing plants maintained a better K+/Na+ ratio and higher Ca2+ content under salt stress. The higher K+/Na+ maintenance in transgenic plants was mainly achieved by increasing Na+ efflux and K+ retention in roots via regulating the expression of the related ion channel genes. Stress-responsive genes, including P5CS1, RD29A, DREB2 and KIN2, were upregulated in transgenic plants under salt stress.
These results suggest that MsPIP2;2 confers salt tolerance by regulating antioxidant defence system-mediated ROS scavenging, K/Na ion homeostasis and stress-responsive gene expression in plants.
Fig. 9. The net flux of Na+ and K+ at the root tip elongation zones of 7-day-old Arabidopsis seedlings. (A) The net Na+ flux under normal conditions (0 mM NaCl). (B) The net Na+ flux after 150 mM NaCl stress. (C) The mean Na+ flux. (D) The net K+ flux under normal conditions (0 mM NaCl). (E) The net K+ flux after 150 mM NaCl stress. (F) The mean K+ flux. Bars represent the mean ± SE (n = 3). Asterisks and double asterisks above the bars indicate significant differences between the transgenic lines and the WT under the same growth conditions: *, P < 0.05; **, P < 0.01.
标题:Tissue-specific respiratory burst oxidase homologue -dependent H2O2 signaling to the plasma membrane H+-ATPase confers potassium uptake and salinity tolerance in Cucurbitaceae
影响因子:5.360
检测指标: K+流速
检测部位:距离根尖1mm
K+流实验处理方法:
5日龄黄瓜幼苗,75mM NaCl处理24小时
K+流实验测试液成分:
0.5mM KCl,0.1mM CaCl2,pH 5.7
作者:华中农业大学别之龙、黄远
英文摘要
Potassium (K+) is a critical determinant ofsalinity tolerance, and H2O2 has been recognised as an important signalingmolecule that mediates many physiological responses. However, the details onhow H2O2 signaling regulates potassium uptake in the root under salt stressremain elusive. In this study, the salt sensitive cucumber and salt tolerantpumpkin which belong to the same family cucurbitaceae were used to answer theabove question.
Weshow that higher salt tolerance in pumpkin was related to its superior abilityfor K+ uptake and higher H2O2 accumulation in the root apex. Transcriptomeanalysis showed that salinity induced 5886 (3005 up and 2811 down) and 4679(3965 up and 714 down) differentially expressed genes (DEGs) in cucumber andpumpkin, respectively. DEGs encoding NADPH oxidase (RBOHD), 14-3-3 protein(GRF12), plasma membrane H+- ATPase (AHA1) and potassium transporter (HAK5)showed higher expression in pumpkin than cucumber under salinity stress.Treatment with a NADPH oxidase inhibitor diphenylene iodonium resulted in alower RBOHD, GRF12, AHA1 and HAK5 expression, reduced plasma membrane H+-ATPase activity, and smaller K+ uptake, resulting in a loss of salinitytolerance trait in pumpkin. The opposite results were obtained when the plantswere pre-treated with exogenous H2O2. Knocking out of RBOHD in pumpkin byCRISPR-Cas9 editing of coding sequences resulted in lower root apex H2O2 and K+content and GRF12, AHA1 and HAK5 expression, ultimately resulting in asalt-sensitive phenotype. However, ectopic expression of pumpkin RBOHD inArabidopsis led to the opposite effect.
Taken together, this study shows that RBOHD-dependent H2O2 signaling in the root apex is important for the pumpkin salttolerance and suggests a novel mechanism that confers this trait, namelyRBOHD-mediated transcriptional and post-translational activation of plasmamembrane H+-ATPase operating upstream of HAK5 K+ uptake transporters.
Figure 7. Relative expression of GRF (14-3-3 protein), AHA (plasma membrane H+-ATPase) and HAK5 (high affinity K+ transporter) in the root apex of cucumber (A, C, E) and pumpkin (B, D, F) exposed to 75 mM NaCl for 24 h. (G) to (J): plasma membrane H+-ATPase activity and net K+ flux measured after 24 h of exposure to 75 mM NaCl stress from the root apex pre-treated for 1 h in solutions containing specific chemicals (DPI, an NADPH oxidase inhibitor, H2O2) in cucumber (G, I) and pumpkin (H, J). Values are the mean ± SE (n=4). Different letters indicate significant difference (P < 0.05) according to Duncan's multiple range tests. The gene ID for cucumber GRF, AHA and HAK5 is Csa3G890040 (GRF8), Csa1G045600 (AHA11) and Csa3G835810 (HAK5), and it is CmoCh01G016540 (GRF12), CmoCh11G003690 (AHA1) and CmoCh08G004000 (HAK5) for pumpkin.
标题:Phosphatase GhDsPTP3a interacts with annexin protein GhANN8b to reversely regulate salt tolerance in cotton (Gossypium spp.)
影响因子:7.299
检测指标:Ca2+、Na+、K+流速
Ca2+流实验方法:
7d拟南芥,100 mM NaCl瞬时盐胁迫处理,检测距根尖1000微米的点
Ca2+流实验测试液成份: 0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, 0.1 % sucrose, pH 6.0
K+、Na+流实验方法:
· 5d拟南芥,0、100 mM NaCl处理24h,检测距根尖200微米的点 · 6d拟南芥,50 uM LaCl3+100 mM NaCl处理24h,检测距根尖200微米的点
K+、Na+流实验测试液成份: 0.5 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.1 mM NaCl, 0.3 mM MES, pH 6.0
作者:中国农业大学李芳军、穆春、得州农工大学单立波
英文摘要
Salinity is among the major factorslimiting crop production worldwide. Despite having moderate salt‐tolerance,cotton (Gossypium spp.) suffers severe yield losses to salinity stresses,largely due to being grown on saline‐alkali and drylands.
To identify genetic determinants conferringsalinity tolerance in cotton, we deployed a functional genomic screen using acotton cDNA library in a virus‐induced gene silencing (VIGS) vector. We have revealed thatsilencing of GhDsPTP3a, which encodes a protein phosphatase, increases cottontolerance to salt stress.
Yeast two‐hybrid screensindicated that GhDsPTP3a interacts with GhANN8b, an annexin protein, whichplays a positive role in regulating cotton response to salinity stress. Saltstress induces GhANN8b phosphorylation, which is subsequently dephosphorylated byGhDsPTP3a. Ectopic expression of GhDsPTP3a and GhANN8b oppositely regulatesplant salt tolerance and calcium influx. In addition, we have revealed thatsilencing of GhDsPTP3a or GhANN8b exerts opposing roles in regulating GhSOS1transcript levels, and ectopic expression of GhANN8b elevates Na+ efflux inArabidopsis under salinity stress.
Our study demonstrates that a cottonphosphatase GhDsPTP3a and an annexin protein GhANN8b interact and reverselymodulate Ca2+ and Na+ fluxes in cotton salinity responses.
(b) Ectopic-expression of GhDsPTP3a or GhANN8b alters extracellular Na+ efflux upon salt stress in live roots via NMT assay. (c) LaCl3 blocks GhANN8b-induced Na+ efflux upon salt stress in live roots via NMT assay.
标题:Root vacuolar Na+ sequestration but not exclusion from uptake correlates with barley salt tolerance
影响因子:5.775
检测指标:Na+、H+
通讯作者:塔斯马尼亚大学Sergey Shabala,华中农业大学吴洪洪
英文摘要
Soil salinity is a major constraint for the global agricultural production. For many decades, Na+ exclusion from uptake has been the key trait targeted in breeding programs; yet, no major breakthrough in creating salt tolerant germplasm was achieved.
In this work, we have combined the MIFE technique for non‐invasive ion flux measurements with confocal fluorescence dye imaging technique to screen 45 accessions of barley to reveal the relative contribution of Na+ exclusion from the cytosol to the apoplast and its vacuolar sequestration in the root apex, for the overall salinity stress tolerance.
We show that Na+/H+ antiporter‐mediated Na+ extrusion from the root plays a minor role in the overall salt tolerance in barley. At the same time, a strong and positive correlation was found between root vacuolar Na+ sequestration ability and the overall salt tolerance. The inability of salt sensitive genotypes to sequester Na+ in root vacuoles was in a contrast to a significantly higher expression levels of both HvNHX1 tonoplast Na+/H+ antiporters and HvVP1 H+‐pumps compared with tolerant genotypes. This data is interpreted as a failure of sensitive varieties to prevent Na+ back‐leak into the cytosol and existence of a futile Na+ cycle at the tonoplast.
Taken together, our results demonstrated that root vacuolar Na+ sequestration but not exclusion from uptake played the main role in barley salinity tolerance and suggested that the focus of the breeding programs should be shifted from targeting genes mediating Na+ exclusion from uptake by roots to more efficient root vacuolar Na+ sequestration.
Co-expression of SpSOS1 and SpAHA1 in transgenic Arabidopsis plants improves salinity tolerance. BMC Plant Biology, 2019, 19(1):74.
Overexpression of the PtSOS2 gene improves tolerance to salt stress in transgenic poplar plants. Plant Biotechnology Journal, 2015, 13(7): 962-73.
Co-expression of the Arabidopsis SOS genes enhances salt tolerance in transgenic tall fescue (Festuca arundinacea Schreb.). Protoplasma, 2014, 251(1):219-31.
SOS1 gene overexpression increased salt tolerance in transgenic tobacco by maintaining a higher K+/Na+ ratio. Journal of plant physiology, 2012, 169(3): 255-261.
Nax loci affect SOS1-like Na+/H+ exchanger expression and activity in wheat. Journal of Experimental Botany, 2016, 67(3):835-44.
Haem oxygenase modifies salinity tolerance in Arabidopsis by controlling K+ retention via regulation of the plasma membrane H+-ATPase and by altering SOS1 transcript levels in roots. Journal of Experimental Botany, 2013, 64(2): 471-481.
Na+-H+ antiporter activity of the SOS1 gene, lifetime imaging analysis and electrophysiological studies on Arabidopsis seedlings. Physiologia Plantarum, 2009,137(2):155-65.
作者: xuyuenmt 更新时间:2022-07-05 07:49
JXB:华中农大别之龙|离子流揭示中国南瓜与印度南瓜的耐盐策略
2018年7月,华中农大园艺林学学院别之龙教授团队关于不同遗传背景南瓜材料耐盐性策略差异的研究成果在Journal of Experimental Botany上发表题为An early ABA-induced stomatal closure, Na+ sequestration in leaf vein and K+ retention in mesophyll confer salt tissue tolerance in Cucurbita species的研究成果。牛蒙亮、陈晨、谢俊俊为本文共同第一作者,别之龙、黄远为并列通讯作者。
葫芦科中南瓜具有较强的耐盐性,在瓜类嫁接中广泛用作黄瓜、西瓜等盐敏感材料的砧木,具有较强的限制Na+等盐害离子向地上部运转的能力,其中生产中的南瓜砧木多为中印南瓜杂合体(Cucurbita maxima × Cucurbita moschata)材料。
前期研究发现,中国南瓜(Cucurbita moschata)和印度南瓜(Cucurbita maxima)二者具有显著差异的Na+积累模式与耐盐能力(A shoot based Na+ tolerance mechanism observed in pumpkin—An important consideration for screening salt tolerant rootstocks. 2017, Scientia Horticulturae, 218:38-47.),某些特殊的南瓜材料在维持叶片中高Na+含量的同时依然具有极强的耐盐能力,这引起了研究者对这些材料耐盐策略的兴趣,其Na+转运过程具有哪些不同寻常之处?
An early ABA-induced stomatal closure, Na+ sequestration in leaf vein and K+ retention in mesophyll confer salt tissue tolerance in Cucurbita species. Journal of Experimental Botany. 2018, 69(20):4945-4960.
Root respiratory burst oxidase homologue-dependent H2O2 production confers salt tolerance on a grafted cucumber by controlling Na+ exclusion and stomatal closure. Journal of Experimental Botany. 2018, 69(14):3465-3476.(JXB:华中农大别之龙NMT揭示嫁接黄瓜根源H2O2促耐盐机制)
Scanning ion-selective electrode technique and X-ray microanalysis provide direct evidence of contrasting Na+ transport ability from root to shoot in salt-sensitive cucumber and salt-tolerant pumpkin under NaCl stress. Physiologia Plantarum. 2014, 152(4):738-48.
致 谢
感谢本文第一作者牛蒙亮博士供稿。 欢迎大家联系我们踊跃投稿,010-8262 4800。
作者: xuyuenmt 更新时间:2022-07-05 07:52
SCI REP-UK :山东农大丨NaCl胁迫下磁处理可调控杨树N代谢
期刊:Scientific Report
主题:NaCl胁迫下磁处理可调控杨树N代谢
标题:The effects of magnetic treatment on nitrogen absorption and distribution in seedlings of Populus × euramericana ‘Neva’ under NaCl stress
NH4+、NO3-流实验测试液成份: NH4+: 0.1 mM NH4NO3, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5 NO3-: 0.1 mM NH4NO3, 1.0 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
作者:山东农业大学林学院马风云、刘秀梅
英文摘要
A potted experiment with Populus × euramericana ‘Neva’ was carried out to assess whether there are positive effects of magnetic treatment of saline water (MTSW) on nitrogen metabolism under controlled conditions in a greenhouse. Growth properties, nitrogen contents, enzyme activities and metabolite concentrations were determined based on field experiments and laboratory analysis after a 30-day treatment.
The results were as follows: (1) Biomass accumulation, root morphological properties and total nitrogen content were improved by MTSW. (2) Magnetization led to a greater increase in nitrate-nitrogen (NO3−-N) content in roots than in leaves, accompanied by greater NO3− efflux and activated nitrate reductase. (3) MTSW led to a higher ammonium-nitrogen (NH4+-N) content and greater uptake of net NH4+ in the leaves than that in the roots. (4) Magnetization stimulated glutamine synthase, glutamate dehydrogenase and glutamate synthase activities, whereas the concentrations of glutathione and oxidized glutathione were increased in leaves but decreased in roots, and the total glutathione content was increased.
Overall, these results indicated some beneficial impacts of MTSW on nitrogen translocation under field conditions, especially for equilibrating the distribution of NO3−-N and NH4+-N. Moreover, these findings confirmed the potential of using low-quality water for agriculture.
标题:Phosphatidylserine Synthase from Salicornia europaea Is Involved in Plant Salt Tolerance by Regulating Plasma Membrane Stability
作者:中科院植物所李银心、吕素莲、台方
检测离子/分子指标
K+
检测样品
盐角草根细胞
中文摘要(谷歌机翻)
盐诱导的脂类改变在许多植物物种中已有报道,然而,脂类生物合成和代谢如何调控,脂类在植物耐盐性中如何发挥作用的研究却少得多。在本研究中,盐角草细胞质膜(PM)中磷脂酰丝氨酸(PS)含量明显高于拟南芥。随后从盐角草中分离到一个编码磷脂酰丝氨酸合成酶(PSS)的基因,命名为SePSS。多重比对和系统发育分析表明,SePSS属于碱基交换型PSS,位于内质网。在400或800 mM NaCl胁迫下,SePSS在盐角草悬浮细胞中的失活导致PS含量降低,细胞存活率降低,PM去极化和K+外排增加。相比之下,SePSS的上调导致拟南芥PS和磷脂酰乙醇胺(PE)水平升高,耐盐性增强,同时转基因株系中活性氧积累比WT低,膜损伤较少,PM去极化较少,K+/Na+较高。这些结果表明,PS水平与植物耐盐性呈正相关,SePSS通过调节PS水平参与植物耐盐性,进而调节PM电位和通透性,维持离子稳态。本研究的工作内容为改善植物在多重胁迫下的生长提供了一个潜在的策略。
离子/分子流实验处理
0、400、800 mM NaCl处理2 h
离子/分子流实验结果
盐胁迫下,植物的PM常常会发生去极化,导致K+从细胞中渗出。为了研究SePSS在盐胁迫下调节膜电位的可能作用,分别用0、400和800 mM NaCl处理空载体(empty vector,EV)细胞和SePSS-RNAi细胞。采用非损伤微测技术(NMT)检测K+净流速,与无盐处理相比,400和800 mM NaCl处理使EV细胞K+内流减少,800 mM NaCl处理使SePSS-RNAi细胞K+由内流转为外排(图1)。这些结果表明,敲除SePSS可能会加剧NaCl诱导的PM去极化,从而导致K+从细胞中渗漏。
标题:Changes in Expression Level of OsHKT1;5 Alters Activity of Membrane Transporters Involved in K+and Ca2+ Acquisition and Homeostasis in Salinized Rice Roots
当向WT植株根施加80 mM NaCl(模拟木质部汁液Na+浓度的增加)时,可测到强烈而持续的净Na+吸收(图1A, C)。从功能上讲,这种吸收与根木质部对Na+的重吸收是一致的(无论是通过HKT1;5还是通过一些其他运输系统)。然而,在NIL(SKC1)中,没有这种吸收。相反,敲低(Knockdown, KD)株系表现出木质部薄壁细胞对Na+的净吸收甚至略高于WT(图1A,C)。这些结果与本文全株Na+含量数据结果一致。
② 100 mM NaCl处理24 h,然后转移到无钠的1/4 Hoagland营养液中,在有无H2的情况下处理60 min
③ HRW处理30 min后,100 mM NaCl实时处理
④ HRW+100 mM NaCl同时实时处理
⑤ HRW处理30 min后,10 mM H2O2实时处理
⑥ HRW+10 mM H2O2同时实时处理
离子/分子流实验结果
植物体内Na+含量降低可能与Na+吸收降低或Na+外排速率增加有关。这些可能性使用非损伤微测技术(NMT)得到了验证。盐处理诱导根表皮产生大量的Na+瞬时净流入(图1A);在经过HRW预处理的根中,这种内流大约减少50%。研究随后试图评估一种可能性,即上述净Na+吸收的差异是由于Na+外排速率较高所致。用100 mM NaCl溶液处理根系24 h后,将根系转移到不含H2的无钠测试液中。HRW预处理后的根系中Na+净外排速率提高了2倍(图1B),与上述结果一致。
图1. HRW对5日龄大麦幼苗成熟区的Na+净流速影响。(A)加入100 mM NaCl,在不同时间点(处理后10、30、60和120 min)测量Na+净流速。(B)从100 mM NaCl溶液(24 h处理)转移到无钠的1/4 Hoagland's溶液中,在有无H2情况下处理60 min后测量的稳定Na+外排速率。正值表示吸收,负值表示外排。
图3. HRW对实时10 mM H2O2处理下5日龄大麦幼苗成熟根区测定的实时K+(A)和Ca2+(B)流速的影响。“Pre-HRW”是指在加入10 mM H2O2和NaCl之前,将幼苗转入HRW溶液中30 min。在“HRW”处理中,HRW与H2O2一起添加到溶液中。
其他实验结果
在没有盐胁迫的情况下,HRW可以增加根长,但不会显著影响鲜重、叶片叶绿素含量或叶绿素荧光Fv/Fm。轻度(100 mM NaCl)盐胁迫会显著抑制根系生长(例如减少长度);施用HRW可以大大减轻这种抑制作用。与对照相比,更严重的胁迫(200 mM NaCl)导致植物的根更短,鲜重更低,叶绿素含量或Fv/Fm更低。施用HRW可以强烈逆转盐度的这些不利影响。
FDA-PI双色荧光染色结果显示,在对照或HRW条件下,死细胞不超过10%,在100 mM NaCl处理下,该比例增加。在施用HRW下,这种损伤明显缓解。NaCl处理诱导大麦苗根部H2O2的大量积累,与对照和HRW处理相比,H2O2的积累增加了3倍以上。这种增加被HRW有效抑制。
标题:Leaf mesophyll K+ and Cl- fluxes and reactive oxygen species production predict rice salt tolerance at reproductive stage in greenhouse and field conditions
为了进一步了解SLAH3 S601位点的生理作用,研究采用非损伤微测技术(NMT)对硝酸盐流速进行了分析。为检验Cl-是否干扰NMT系统中NO3-的检测,在无幼苗的情况下分别检测测试液1(1 mM KNO3, 0.1mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 6.0)和测试液2(1 mM KNO3, 1.1 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 6.0)中NO3-的浓度和净流速。Cl-的存在不干扰NO3-的检测(图2)。其次,本研究检测了根尖附近成熟区的NO3-净流速(图1A,图3A)。对Col-0、slah3-3、slah3-4幼苗和所有互补株系在1/2 MS培养基上生长8 d后转入高NH4+/低pH条件(1 mM NO3-, 10 mM NH4+, pH 4.5)或非高NH4+/低pH条件(1 mM NO3-, 1 mM NH4+, pH 5.7)2 h后进行检测。在6 min内检测到来自植物根系的NO3-流速(图1B,图3B)。在高NH4+/低pH胁迫下,Col-0的NO3-外排速率平均值约为93 pmol cm-2s-1,slah3突变体的NO3-外排速率平均值约为0 pmol cm-2s-1。slah3-4背景下的互补株系SLAH3和SLAH3 S601A显示出与Col-0植株类似的硝酸盐外排。相比之下,slah3-4背景下互补株系SLAH3 S601D的硝酸盐外排与slah3突变体相似(图1B)。此外,在非高NH4+/低pH胁迫下,所有植物的硝酸盐外排相似,NO3-外排速率的平均值均在0 pmol cm-2s-1左右(图3)。这些结果表示SLAH3的S601在高NH4+/低pH胁迫下对硝酸盐外排起重要的调节作用。
150 mM NaCl短期(ST, 24 h)处理后,胡杨根系稳态O2流速的模式与群众杨不同。研究观察到ST处理后的胡杨根系氧内流速率增加(图3A)。在群众杨根系中,NaCl处理降低了根尖区的O2流速,但在伸长区的O2流速变化不明显(图3B)。为确定盐刺激的胡杨根系O2内流是否是线粒体呼吸被激活的结果,采用线粒体呼吸抑制剂NaN3抑制细胞色素途径。抑制剂NaN3显著降低了NaCl胁迫下胡杨根中O2的内流(图3C),表明ST处理激活了胡杨根细胞的线粒体呼吸。抑制剂NaN3能够显著降低ST处理下群众杨根系中O2的内流速率(图3D),表明植物的线粒体呼吸受到严重抑制。
图3. NaCl和线粒体呼吸抑制剂(NaN3)对胡杨和群众杨根部稳态O2流速的影响。
群众杨是一种盐敏感树种,因此在4周的处理中以50、100、150、200 mM递增的方式增加盐分。在增加盐分处理期间每周检查稳态O2流速。胡杨和群众杨在50 mM NaCl胁迫1周后,沿根轴O2内流速率增加,尽管耐盐杨树受到了更明显的刺激(图4A, B)。然而,在第2周100 mM NaCl胁迫下,群众杨不存在盐刺激的O2吸收(图4D)。本研究注意到,暴露在较高盐度下,即第3周150 mM NaCl和第4周200 mM NaCl,引起了群众杨中O2内流速率的显著下降,且这种影响在根尖区更为明显(图4F, H)。与盐敏感杨树相比,在盐胁迫期间,胡杨表现出沿根轴的O2内流增加,但刺激效果随盐度的增加而下降(图4A, C, E, G)。
图4. 长期增加NaCl对胡杨和群众杨根部O2流速的影响。
木本植物和草本植物的耐盐性在很大程度上是由Na+从细胞质中排出所介导的。为证实盐环境下胡杨根细胞稳定的线粒体呼吸是否能激活H+-ATPase以维持Na+稳态,本研究在盐胁迫下,检测了线粒体呼吸抑制剂NaN3对Na+外排和体内H+-ATPase活性的影响。NaCl(150 mM, 24 h)引起两种杨树根尖Na+外排显著增加(图5A)。值得注意的是,在NaCl处理下胡杨根系的Na+外排速率明显高于群众杨(图5A)。然而,抑制剂NaN3显著降低了NaCl胁迫下根系Na+外排速率(图5A),表明线粒体呼吸受到抑制后,Na+外排减少。在无盐对照条件下,NaN3没有明显改变Na+流速,这在两种杨树中几乎无法检测到(图5A)。
用NMT研究了NaCl胁迫下根中PM H+-ATPase的活性。NaCl处理(150 mM, 24 h)使H+的净内流速率在两个杨树根系中增加(图5B),这是Na+/H+跨PM逆向转运所致的(图5A, B)。NaN3增加了盐刺激下的H+内流(图5B),而抑制剂处理的根系中没有相应的增加Na+外排(图5A)。因此,抑制剂引起的H+内流主要是由质膜H+-ATPase产生的H+外排减少引起的。此外,NaN3导致两种杨树对照根中H+内流的增加(图5B),这是由于抑制剂处理下根中H+泵活性降低所致。
图5. NaCl和线粒体呼吸抑制剂(NaN3)对胡杨和群众杨根系Na+和H+稳态流速的影响。
图6. 植物根部检测图
其他实验结果
50 mM NaCl处理1周后,群众杨根部的整体呼吸量增加。然而,随着NaCl浓度和盐胁迫时间的增加,群众杨根部的呼吸速率呈下降趋势,呼吸速率在第3~4周达到最低值。与群众杨相反,NaCl处理的胡杨根的呼吸速率在处理1周后明显增加,在随后的3周盐胁迫中仍比对照植物高36~44%。
标题:Salt stress-induced H2O2 and Ca2+ mediate K+/Na+ homeostasis in Pyropia haitanensis
第一作者:王文磊、邢磊;通讯作者:谢潮添,集美大学
检测离子/分子指标
Na+,K+,H2O2,Ca2+
检测样品
坛紫菜叶状体
中文摘要
集美大学谢潮添教授课题组2019年在Algal Research(IF:4.008)上发表的题为“K+ and Na+ transport contribute to K+/Na+ homeostasis in Pyropia haitanensis under hypersaline stress”的文章首次从离子转运的角度报道了紫菜的耐盐机制。文章以坛紫菜为材料,结果表明,110‰盐胁迫下藻体仍能维持较高的K+/Na+。进一步通过NMT分析发现,藻体主要通过激活PM H+泵,驱动Na+/H+逆向转运体将细胞质外的Na+排出到质外体中,并通过去极化激活的外向整流型K+通道部分缓解K+的损失,从而维持较高的K+/Na+比值应对高盐胁迫。
为了了解NRT1.1在根系K+吸收中的作用,研究使用NMT系统检测了植物根系的K+流速,发现在2.0和0.05 mM K+培养基中,nrt1.1-1和chl1-5突变体根系伸长区和成熟区的K+净内流速率均低于Col-0植株的50%。相比之下,植物根系分生区净K+内流速率没有显著差异(图2B, C)。结果表明伸长区和成熟区是NRT1.1与根细胞K+吸收相关的靶区域。
标题:Soybean CHX-type ion transport protein GmSALT3 confers leaf Na+ exclusion via a root derived mechanism, and Cl- exclusion via a shoot derived process
使用100 mM NaCl处理发现,NIL-S地上部分、茎和叶中的Cl-、K+含量更高,K+/Na+比却降低了,NIL-T叶片中的K+/Na+比在胁迫第3 d后才明显升高。
盐处理10 d后,NIL-T的根、茎、叶干重明显增加。
100 mM NaCl处理4 d后发现,Na+、Cl-在NIL-S的所有气生组织中积累得更多。
在根部(主根和侧根),NIL-T比NIL-S积累的Cl-多。
100 mM NaCl处理4 d后,检测大豆茎韧皮部和木质部汁液中的离子浓度。与NIL-T相比,NIL-S的木质部汁液中的Na+浓度明显更高。与叶片的数据相反,NIL-S的木质部和韧皮部汁液中的Cl-浓度比NIL-T低。
对交互嫁接和自嫁接(self-grafted,对照)的植株进行100 mM NaCl处理8 d,结果发现在NIL-S砧木上嫁接NIL-T接穗,叶片Cl-含量比自嫁接NIL-S低。相反,当NIL-S接穗嫁接到NIL-T砧木上时,叶片中Cl-含量与自嫁接NIL-S相比差异不显著。与自接NIL-T植株相比,自接NIL-S植株的Cl-含量要高得多。
标题:Changes in Expression Level of OsHKT1;5 Alters Activity of Membrane Transporters Involved in K+ and Ca2+ Acquisition and Homeostasis in Salinized Rice Roots
研究采用非损伤微测技术(MIFE),测定了NIL(SKC1)水稻木质部薄壁组织的Na+流速。当向WT植株根中柱施加80 mM NaCl(模拟木质部汁液Na+浓度的增加)时,可测出强烈而持续的Na+吸收(图1A, C)。从功能上讲,这种吸收与根系木质部(通过HKT1;5或其他转运系统)对Na+的重吸收是一致的。然而,在NIL(SKC1)中,这种吸收是不存在的。相反,KD株系的木质部薄壁细胞对Na+的吸收甚至比WT系略高(图1A, C)。
标题:Dynamic changes of phosphatidylinositol and phosphatidylinositol 4-phosphate levels modulate H+-ATPase and Na+/H+antiporter activities to maintain ion homeostasis in Arabidopsis under salt stress
H+:7日龄拟南芥幼苗在含有75 mM NaCl的MS培养基中培养24 h。 Na+:7日龄拟南芥幼苗在含有100 mM NaCl的MS培养基中培养24 h。离子/分子流实验结果使用非损伤微测技术(NMT)检测Col-0, pis1-1, pis1-2,COM1 and COM2的H+流速。将7日龄幼苗转入含75 mM NaCl(pH 8.1)的MS培养基中培养24 h,测定根尖H+流速。pis1-1和pis1-2植物的H+流速与Col-0相比显著增加,而COM1和COM2植物的H+流速与Col-0植物相同(图1C, D)。因此,在PI含量减少的pis1突变体中,PM H+-ATPase活性增加,表明PI在体内抑制了PM H+-ATPase的活性。
6日龄草莓幼苗100 mM NaCl、100 μM NaCl+0.57 mM IAA、0.57 mM IAA处理3 d或6 d。离子/分子流实验结果不同处理下,Na+流速和Na+含量的变化趋势相同。处理6 d后,与对照相比,NaCl和NaCl+IAA均增加了根(图1D)和叶片(图1C)的Na+流速,但与NaCl+IAA处理相比,根系Na+流速对NaCl的响应更高。在叶片中,结果相反。NaCl处理下Na+流速增幅较大,叶片与根系相比增加了5.5倍,NaCl+IAA处理下叶片比根系增加11倍。
不同处理下K+流速与K+含量的变化趋势相同,NaCl处理下,叶片和根系K+流速均高于其他3个处理。
图1. 高盐条件下,第3天添加生长素可促进草莓根系Na+外排,第6天添加生长素可促进草莓叶片Na+外排。高盐度条件下草莓根系K+流速在第6天被生长素的添加所抑制。(A)(E)第3天草莓叶片Na+流速(A)和K+流速(E),(B)(F)第3天草莓根系Na+流速(B)和K+流速(F),(C)(G)第6天草莓叶片Na+流速(C)和K+流速(G),(D)(H)第6天草莓根系Na+流速(D)和K+流速(H)经NaCl(100 mM )、IAA(0.57 mM )及其组合处理。正值代表Na+、K+外排。
选取0.1 mM 水杨酸(SA)、蒸馏水(对照)处理,盐碱土培养3 d后的羊草种子测定Na+、K+、Ca2+流速,另外选取0.1 mM 水杨酸和对照浸种12 h后和盐碱土培养3 d后的羊草种子进行O2的测定。离子/分子流、离子浓度成像实验结果研究采用非损伤微测技术(NMT)测定萌发种子表面的O2内流。结果表明,萌发培养3 d后,0.1 mM SA处理下萌发种子的O2速率显著高于对照(图1H),但盐碱胁迫下种子的呼吸强度有所降低。此外,0.1 mM SA处理后O2内流速率显著高于对照(图1I),说明SA可以提高盐碱胁迫下羊草种子的发芽率和活力。
图1. 羊草种子O2吸收。
为了进一步探究为什么用0.1 mM SA处理会减少Na+的含量,而增加Ca2+、K+的积累,研究用NMT测量了用0.1 mM SA处理和对照组在培养3 d后的发芽种子的胚顶部的Na+、K+和Ca2+的流速和浓度空间成像。结果显示,0.1 mM SA处理和对照组都明显表现出Na+的外排(图2A),但0.1 mM SA处理表现出比对照组更高的Na+外排,Na+的平均速率达到1144 pmol cm-2⋅s-1,与对照组相比,增加了4.66倍(图2B)。Na+浓度空间成像表明,虽然对照处理下种子表面Na+含量增加,但种子表面Na+积累量明显低于SA处理(图2C)。与对照K+的外排不同,0.1 mM SA处理下萌发的种子虽然K+流速较低,但仍然是内流(图2D),种子胚顶部的平均内流速率仅为0.68 pmol cm-2·s-1。值得注意的是,对照组中K+平均外排速率达到341.81 pmol cm-2⋅s-1(图2E),对照组中萌发种子表面的K+浓度也明显低于SA处理时的浓度,表明对照组中发生了巨大的K+外排(图2F)。Ca2+流速数据表明,在用0.1 mM SA处理和对照组中,检测到稳定的Ca2+外排(图2G)。与对照组相比,用0.1 mM SA处理后的Ca2+外排速率明显降低(图2H),用0.1 mM SA处理的种子表面的Ca2+浓度也比对照组低(图2I)。图2. 在盐碱胁迫下,外源SA改变了羊草发芽种子表面的离子流速。(A) Na+的瞬时流速 (B) Na+平均流速 (C) 种子表面Na+浓度空间成像(0-150 μm)。(D) K+的瞬时流速 (E) K+平均流速 (F) 种子表面K+浓度的空间成像(0-150 μm)。(G) Ca2+的瞬时流速 (H) Ca2+平均流速 (I) 种子表面Ca2+浓度空间成像(0-150 μm)。
其他实验结果
外源SA提高了羊草种子的活力和发芽率。
盐碱胁迫下外源SA影响了种子休眠。
盐碱胁迫下外源SA激活了羊草种子抗氧化酶系统。
外源SA缓解了盐碱胁迫对质膜的损伤。
盐碱胁迫下外源SA改变了Na+、K+和Ca2+的积累。
盐碱胁迫下外源SA触发转录水平的变化。
结论综上所述,合理剂量的外源SA可以作为渗透调节剂促进羊草种子萌发,0.1 mM SA的施用浓度有效提高了盐碱胁迫下羊草种子的活力和萌发。通过增加内源SA和O2流入,SA在平衡羊草萌发种子中的内源性激素和渗透物方面发挥了重要的渗透调节作用(图3)。此外,外源SA通过调节信号因子H2O2、渗透物质以及Na+、K+、Ca2+等离子在羊草种子萌发过程中的积累,提高抗氧化酶活性,保护细胞膜的完整性。本研究表明,SA主要通过调控盐碱胁迫下羊草种子萌发过程中离子分泌和渗透调节物质积累途径发挥作用,外源SA将为促进盐碱化土壤羊草种子萌发和繁殖提供有效参考。调节外源SA介导的植物种子的生理和渗透响应,也揭示了在非生物胁迫下减轻渗透胁迫对发芽种子的损害的一个启示。图3. 盐碱胁迫下,SA介导羊草种子萌发的一种假设调控途径。
测试液
0.1 mM CaCl2, 0.1 mM KCl, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, pH 6.0
标题:Tissue tolerance mechanisms conferring salinity tolerance in a halophytic perennial species Nitraria sibirica Pall.
作者:中国林科院国家林业和草原局盐碱地研究中心张华新、杨秀艳、唐晓倩、张会龙
检测离子/分子指标
K+、Na+、H+
检测样品
西伯利亚白刺叶肉组织
中文摘要
植物的耐盐性依赖于不同组织和器官的协调运转。组织耐盐性是赋予植物适应盐环境的关键性状之一。这一特性意味着在代谢活跃的细胞中能够维持较低的胞质Na+/K+比值。本研究以多年生木本盐生植物西伯利亚白刺(Nitraria sibirica)为材料,探讨其耐盐性机制。结果表明,100~200 mM NaCl处理刺激了幼苗的生长。离子分布结果表明,叶片起到Na+库的作用,而植物根系具有优越的保K+能力。从土壤中吸收的过量Na+主要转运到地上部分,最终被区隔在叶肉细胞的液泡中。因此,在盐胁迫下西伯利亚白刺能够在组织和细胞水平上特异性保持K+/Na+的最适平衡。为此,西伯利亚白刺叶肉细胞中液泡H+-ATPase和H+-PPase酶活性升高, NsVHA、NsVP1和NsNHX1基因的表达上调。NsVHA、NsVP1和NsNHX1介导的叶肉液泡Na+区隔化降低了细胞质中Na+浓度,抑制了K+的流失。同时,西伯利亚白刺在转录水平上调TPK的表达,促进K+从液泡向细胞质转移,有助于维持细胞质中K+稳态。综上表明,西伯利亚白刺的液泡Na+区隔化和细胞内K+稳态等组织耐受特性对西伯利亚白刺适应土壤盐渍化具有重要作用。
当15%PEG实施胁迫时,烟草根尖Ca2+外排速率瞬时增加,转基因株系的Ca2+外排速率是WT植株的0.9~1.4倍(图1A)。在200 mM NaCl胁迫下,转基因植株也观察到较高的Ca2+外排速率(142.0~156.8%)(图1C),结合[Ca2+]cyt结果说明CbFAD3-过表达植物中PM Ca2+-ATPase的持续激活改变了早期胁迫时诱导的Ca2+信号传递。
标题:Leaf mesophyll K+ and Cl- fluxes and reactive oxygen species production predict rice salt tolerance at reproductive stage in greenhouse and field conditions
标题:The positive effectof salinity on nitrate uptake in Suaeda salsa
作者:山东师范大学宋杰、刘冉冉、Bing Cui
检测离子/分子指标
NO3-、H+
检测样品
盐地碱蓬
中文摘要
硝酸盐在盐生植物的耐盐性中起着营养和渗透双重作用。然而,盐生植物在盐碱条件下如何吸收NO3-仍不清楚。在0.5 mM的NO3--N条件下,用0、200和500 mM的NaCl处理盐地碱蓬幼苗,同时添加或不添加Na3VO4(质膜H+-ATPase抑制剂)处理24 h。200 mM NaCl处理上调了根中硝酸盐转运蛋白2.1(SsNRT2.1)的基因表达,增加了根中H+和NO3-的内流,以及叶和根中15NO3-的积累。SsNRT2.1在200 mM NaCl+Na3VO4处理下的表达量显著高于不加Na3VO4处理,而在叶片和根中15NO3-的积累量则相反。在200mM NaCl下,施加Na3VO4对根系H+净流速无显著影响,但诱导根系NO3-净外排。盐度可直接激活SsNRT2.1的表达,并通过增加PM H+-ATPase泵入H+促进盐地碱蓬对NO3-的吸收,这可能解释了为什么某些盐生植物在低NO3-和高盐度条件下吸收和积累高浓度NO3-的原因。
离子/分子流实验处理方法
①0、200、500 mM NaCl处理1 d。 ②0+150 μM Na3VO4、200+150 μM Na3VO4、500 mM NaCl+150 μM Na3VO4处理1 d。
离子/分子流实验结果
与0 mM NaCl相比,200 mM NaCl明显诱导净NO3-内流。然而,500 mM NaCl诱导净NO3-外排(图1a, b)。当加入150 μM Na3VO4时,0、200和500 mM NaCl诱导了NO3-净外排,特别是在500 mM NaCl处理下(图1a, b)。
在0 mM NaCl+0 mM Na3VO4处理下H+外排,在200、500 mM NaCl和0+150 μM Na3VO4、200+150 μM Na3VO4和500 mM NaCl+150 μM Na3VO4处理时H+内流(图1c, d)。与0 mM NaCl相比,200 mM NaCl显著诱导了H+的内流。与不添加Na3VO4的处理相比,添加150 μM Na3VO4显著诱导了所有NaCl浓度处理下的净H+内流(图1c, d)。
在不同浓度NaCl处理下,根和叶中15NO3-的积累趋势与SsNRT2.1的相对表达量一致。盐分增加了根和叶中15NO3-的积累,尤其是在200 mM NaCl下。添加Na3VO4降低了根系和叶片中15NO3-的积累。
无论Na3VO4怎么处理,盐度对根和地上部分的干重影响较小。添加Na3VO4会显著降低0 mM NaCl处理下根和地上部分的干重。
结论
200 mM NaCl增加了盐地碱蓬对NO3-的吸收,这可能是由于PM H+-ATPase增加了H+的泵入。同时,盐度对SsNRT2.1的表达有积极影响。这表明盐度可能直接激活NRT的某些基因,并通过增加PM H+-ATPase对H+的泵送来促进盐生植物盐地碱蓬的NO3-吸收(图2)。这一特性可能解释了为什么盐地碱蓬和其他盐生植物能够在盐度下吸收和积累高浓度的NO3-,即它们能够耐受高盐度,在200~300 mM NaCl下产生最高生物量。
图2. NaCl对盐地碱蓬NO3-吸收的正效应模型。
测试液
NO3-:0.5 mM KNO3, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
H+:0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, pH 6.0
标题:Phosphatidylserine Synthase from Salicornia europaea Is Involved in Plant Salt Tolerance by Regulating Plasma Membrane Stability
作者:中科院植物所李银心、吕素莲、台方
检测离子/分子指标
K+
检测样品
盐角草根细胞
中文摘要
盐诱导的脂类改变在许多植物物种中已有报道,然而,脂类生物合成和代谢如何调控,脂类在植物耐盐性中如何发挥作用的研究却少得多。在本研究中,盐角草细胞质膜(PM)中磷脂酰丝氨酸(PS)含量明显高于拟南芥。随后从盐角草中分离到一个编码磷脂酰丝氨酸合成酶(PSS)的基因,命名为SePSS。多重比对和系统发育分析表明,SePSS属于碱基交换型PSS,位于内质网。在400或800 mM NaCl胁迫下,SePSS在盐角草悬浮细胞中的失活导致PS含量降低,细胞存活率降低,PM去极化和K+外排增加。相比之下,SePSS的上调导致拟南芥PS和磷脂酰乙醇胺(PE)水平升高,耐盐性增强,同时转基因株系中活性氧积累比WT低,膜损伤较少,PM去极化较少,K+/Na+较高。这些结果表明,PS水平与植物耐盐性呈正相关,SePSS通过调节PS水平参与植物耐盐性,进而调节PM电位和通透性,维持离子稳态。本研究的工作内容为改善植物在多重胁迫下的生长提供了一个潜在的策略。
离子/分子流实验处理
0、400、800 mM NaCl处理2 h
离子/分子流实验结果
盐胁迫下,植物的PM常常会发生去极化,导致K+从细胞中渗出。为了研究SePSS在盐胁迫下调节膜电位的可能作用,分别用0、400和800 mM NaCl处理空载体(empty vector,EV)细胞和SePSS-RNAi细胞。采用非损伤微测技术(NMT)检测K+净流速,与无盐处理相比,400和800 mM NaCl处理使EV细胞K+内流减少,800 mM NaCl处理使SePSS-RNAi细胞K+由内流转为外排(图1)。这些结果表明,敲除SePSS可能会加剧NaCl诱导的PM去极化,从而导致K+从细胞中渗漏。
水培条件下CDs通过增强Ca2+信号和Na+稳态来提高甘薯植株的耐盐性。盐处理24 h后,甘薯根尖中IbSOS3和IbSOS2的表达水平提高了约1.9-2.0倍;CDs激活CNGCs,增强根尖(伸长区)中[Ca2+]cyt依赖的SOS通路,从而加速Na+的外排;在盐(150 mm NaCl)处理12天,CDs处理后根、茎和叶组织中Na+的积累分别减少了41%、32%和49%,因此,CDs大大提高了甘薯植株的耐盐性。
标题:The genome of the recretohalophyte Limonium bicolor provides insights into salt gland development and salinity adaptation during terrestrial evolution
作者:山东师范大学王宝山、陈敏、袁芳、王茜、赵博庆、徐晓静、北京贝瑞和康生物技术有限公司史淼
检测离子/分子指标
Na+
检测样品
二色补血草盐腺
中文摘要
盐生植物会进化出专门应对高盐度的方式。极端盐生植物二色补血草(Limonium bicolor)表皮缺乏毛状体,但有盐腺,可排出钠等有害离子,避免盐害。本文利用Illumina短序列、单分子实时长序列、染色体构象捕获(Hi-C)数据和Bionano基因组图谱,报道了一个高质量、2.92Gb染色体规格的二色补血草基因组组装,极大地丰富了具有多细胞盐腺的泌盐盐生植物的基因组信息。虽然二色补血草基因组具有与拟南芥(Arabidopsis thaliana)毛状体命运基因相似的基因,但其与命运决定基因GLABRA3、ENHANCER of GLABRA3、GLABRA2、TRANSPARENT TESTA GLABRA2和SIAMESE缺乏同源性,为该物种缺乏毛状体提供了分子解释。在毛状体经典同源基因中,发现了控制盐腺发育的关键基因LbHLH和LbTTG1的突变显著破坏了盐腺的启动、盐的分泌和盐的耐受性。这为长期存在的盐腺和毛状体可能有共同起源的假设提供了基因支持。此外,二色补血草在与苦荞麦分化后发生了全基因组复制事件,这可能是苦荞适应高盐环境的原因之一。二色补血草的基因组资源为植物耐盐机制的研究提供了丰富的信息,有助于耐盐作物的工程化。
经过7 d的200 mM NaCl处理后,与WT和Mock株系(CR和OE)相比,Lbttg1-cr和Lbhlh-cr两个株系比盐处理前表型增强,具体表现在全株叶片和根系发育上。NaCl处理前后测定根长和单叶面积。尽管盐处理后所有株系均表现出根系伸长和叶片展开明显,但Lbttg1-cr在这两个指标的增加率上均显著优于LbTTG1-OE,Lbhlh-cr的增加率也高于LbHLH-OE。这说明盐处理下CR株系的生长速度明显快于OE株系。
Mean net K+ fluxmeasured from the biofilms in response to treatment with 5 mMand 10mM TEA
英文摘要
Bacteria in biofilms are able to utilize potassium ion channel mediated electrical signaling to achieve cell–cell communication. However, it remains unclear whether these signals play a role in Geobacter sp.when surrounded by an intense electric field.
This study used a potassium channel blocker (tetraethylammonium, TEA) that interfered with the release of K+ but not bacterial growth to demonstrate that potassium ion channel-mediated electrical signaling affected the formation and electroactivity of Geobacter sulfurreducens. The results showed that 5 mM TEA slowed the formation of Geobacter sulfurreducens biofilm, and the current density was ~50% lower than in the control.
The electrochemical analyses showed that the electroactivity of the biofilms with TEA addition was inferior. In particular, the micrometer- scale biofilm with TEA exhibited fewer high current peaks, and the species of outermost groups that participated in the electron transfer in Geobacter sulfurreducens biofilms was different from the control.
This work provides initial evidence to reveal the role of potassium channels in Geobacter sulfurreducens electroactive biofilms.
The dual-affinity nitrate transceptor NITRATE TRANSPORTER 1.1 (NRT1.1) has two modes of transport and signaling, governed by threonine101 (T101) phosphorylation. NRT1.1 regulates lateral root (LR) development by modulating nitrate-dependent basipetal auxin export and nitrate-mediated signal transduction.
Here, using the Arabidopsis thaliana NRT1.1T101D phosphomimetic and NRT1.1T101A non-phosphorylatable mutants, we found that the phosphorylation state of NRT1.1 plays a key role in NRT1.1 function during LR development. Single-particle tracking revealed that phosphorylation affected NRT1.1 spatiotemporal dynamics. The phosphomimetic NRT1.1T101D form showed fast lateral mobility and membrane partitioning that facilitated auxin flux under low-nitrate conditions.
By contrast, non-phosphorylatable NRT1.1T101A showed low lateral mobility and oligomerized at the plasma membrane (PM), where it induced endocytosis via the clathrin-mediated endocytosis and microdomain-mediated endocytosis pathways under high-nitrate conditions.
These behaviors promoted LR development by suppressing NRT1.1-controlled auxin transport on the PM and stimulating Ca2+-ARABIDOPSIS NITRATE REGULATED 1 (ANR1) signaling from the endosome.
2014年12月24日,湖南大学曾光明、陈桂秋、谭琼用NMT在Chemosphere上发表了标题为Physiological fluxes and antioxidative enzymes activities of immobilized Phanerochaete chrysosporium loaded with TiO2 nanoparticles after exposure to toxic pollutants in solution的研究成果。
期刊:Chemosphere
主题:TiO2提升黄孢原毛平革菌镉耐受力的生理证据
标题:Physiological fluxes and antioxidative enzymes activities of immobilized Phanerochaete chrysosporium loaded with TiO2 nanoparticles after exposure to toxic pollutants in solution
影响因子:4.208
检测指标:H+、O2、Cd2+流速
作者:湖南大学曾光明、陈桂秋、谭琼
英文摘要
Immobilized Phanerochaete chrysosporium loaded with TiO2 nanoparticles (PTNs) are novel high-value bioremediation materials for adsorbing cadmium and for degrading 2,4-dichlorophenol (2,4-DCP). The real-time changes in H+ and O2 fluxes were measured using the noninvasive microtest technique (NMT).
The H+ influx increased after the addition of 2,4-DCP, and shifted to efflux following the addition of Cd2+. The O2 flux decreased after the addition of both 2,4-DCP and Cd2+. A larger Cd2+ flux was immediately observed after exposure to 0.5 mM Cd2+ (−351.25 pmol cm−2 s−1) than to 0.1 mM Cd2+ (−107.47 pmol cm−2 s−1). The removal of Cd2+ by the PTNs increased more after treatment with the 0.5 mM exposure solution (27.6 mg g−1) than with the 0.1 mM exposure solution (3.49 mg g−1).
The enzyme activities were analyzed to review the antioxidative defense system of PTNs in a solution containing various concentrations of Cd2+. The activities of the coenzyme nicotinamide adenine dinucleotide (NADH) oxidase as well as the enzyme catalase (CAT) plateaued at 6.5 U g−1 FW and 9.7 U g−1 FW, respectively, after exposure to 0.25 mM Cd2+. The activity of superoxide dismutase (SOD) increased gradually in solutions containing 0.1–0.6 mM Cd2+, and eventually reached a maximum (68.86 U g−1 FW).
These results illustrate how the antioxidative defense system and the physiological fluxes of PTNs respond to the stress caused by toxic pollutants.
加入2,4-DCP后,H+流入量增加,而加入Cd2+后,H+流入量移出。同时添加2,4-DCP和Cd2+后,O2通量下降。暴露于0.5 mM Cd2+(-351.25 pmol cm-2 s-1)后立即观察到更大的Cd2+通量,而不是暴露于0.1 mM Cd2+(-107.47 pmol cm-2 2 s-1)。用0.5 mM暴露溶液(27.6 mg g-1)处理后,PTN去除Cd2+的增加比使用0.1 mM暴露溶液(3.49 mg g-1)处理的增加更多。
分析了酶的活性,以审查包含各种浓度的Cd2+的溶液中PTN的抗氧化防御系统。暴露于0.25 mM Cd2+后,辅酶烟酰胺腺嘌呤二核苷酸(NADH)氧化酶和过氧化氢酶(CAT)的活性分别稳定在6.5 U g-1 FW和9.7 U g-1 FW上。超氧化物歧化酶(SOD)的活性在含0.1–0.6 mM Cd2+的溶液中逐渐增加,并最终达到最大值(68.86 U g-1 FW)。
这些结果说明了PTN的抗氧化防御系统和生理通量如何响应有毒污染物引起的压力。
Fig. 2. (A) Real-time Cd2+ flux of PTNs exposed to 0.1 mM Cd(NO3)2 and 10 mg L
The mean flux of Ca2+ under different pCO2 I scenarios. Mean ± s.d. values per experimental assay are given (n = 3). Upper, Ca2+ efflux under positive phototaxis. Lower, Ca2+ influx under negative phototaxis. ‘−’ on the vertical scale means Ca2+ entry. LC4, flagellar outer dynein arm light chain 4; DC3, outer dynein arm docking complex protein 3; IC138, arm dynein; RSP, radial spoke protein; PF20, a protein of the central pair apparatus; PKA, cAMP-dependent protein kinase; PP2A, protein phosphatase 2A; CK1, casein kinase DIP13/NA14, deflagellation inducible protein; DNAAF3/PF22, axonemal dynein assembly factor. Mean ± s.d. values per experimental assay are given (n = 3). Different letters (a–c) in panel indicate significant differences (P < 0.05) among treatments.
英文摘要
Motility plays a critical role in algal survival and reproduction, with implications for aquatic ecosystem stability. However, the effect of elevated CO2 on marine, brackish and freshwater algal motility is unclear.
Here we show, using laboratory microscale and field mesoscale experiments, that three typical phytoplankton species had decreased motility with increased CO2. Polar marine Microglena sp., euryhaline Dunaliella salina and freshwater Chlamydomonas reinhardtii were grown under different CO2 concentrations for 5 years. Long-term acclimated Microglena sp. showed substantially decreased photo-responses in all treatments, with a photophobic reaction affecting intracellular calcium concentration.
Genes regulating flagellar movement were significantly downregulated (P < 0.05), alongside a significant increase in gene expression for flagellar shedding (P < 0.05). D. salina and C. reinhardtii showed similar results, suggesting that motility changes are common across flagellated species.
As the flagella structure and bending mechanism are conserved from unicellular organisms to vertebrates, these results suggest that increasing surface water CO2 concentrations may affect flagellated cells from algae to fish.
2014年01月14日,中科院水生所王强、陈辉用NMT在Plant and Cell Physiology上发表了标题为Ca2+ Signal Transduction Related to Neutral Lipid Synthesis in an Oil-Producing Green Alga Chlorella sp. C2的研究成果。
期刊:Plant and Cell Physiology
主题:Ca2+流指示的微藻氮胁迫信号转导研究
标题:Ca2+ Signal Transduction Related to Neutral Lipid Synthesis in an Oil-Producing Green Alga Chlorella sp. C2
影响因子:4.134
检测指标:Ca2+流速
作者:中科院水生所王强、陈辉
英文摘要
Changes in the cytosolic Ca2+ levels and the role of Ca2+ signal transduction in neutral lipid synthesis in Chlorella sp. C2 under nitrogen starvation conditions were investigated. The results detected by using the scanning ion-selective electrode technique demonstrate that nitrogen starvation induced significant Ca2+ influx across the plasma membrane into cells.
Ca2+ fluorescence imaging and flow cytometry were used to estimate the effect of this Ca2+ influx on the generation of the Ca2+ signal, and the results showed that the cytosolic Ca2+ concentration increased transiently and then remained at a stable, high level when the cells were exposed to nitrogen starvation. However, the increase could be inhibited by pre-treatment with the Ca2+ channel blockers ruthenium red, verapamil and GdCl3, indicating that both the influx of Ca2+ from the extracellular space via Ca2+ channels that are localized in the plasma membrane and the release of Ca2+ from intracellular calcium storage via the internal calcium store were required for the generation and transduction of the Ca2+ signal.
During nitrogen starvation, neutral lipid synthesis in Chlorella sp. C2 in response to stress conditions was also inhibited to differing degrees by pre-treatment with the three Ca2+ channel blockers, demonstrating the regulation of Ca2+ via these Ca2+ channels in neutral lipid synthesis.
The results suggested that by transduction of extracellular stress signals into the cell and the regulation of the Ca2+ signal in neutral lipid synthesis, Ca2+ signal transduction played important roles in the response mechanism of Chlorella sp. C2 to nitrogen starvation.
Fig. 1 The total Ca2+ flux rates over 5 min in Chlorella sp. C2 under N starvation. (a) Microphotographic examples of Ca2+ ion flux/voltage-clamp measurements. (b) Total flux rates of Ca2+ were detected at 0, 0.5, 2 and 8 d after N starvation. The columns represent the means of three replicated studies in each sample, with the SD of the means (t-test, P < 0.05). The significance of the differences between the control (0 d) and other test values was tested using a one-way analysis of variance. *P < 0.05 vs. control.
Figure 3 Changes in net flux of Cd of periphyton over times (a) and the mean net influx of periphyton (b) under different treatments. Cd0+P, Cd5+P, and Cd50+P represent the periphyton treatment of Cd added at soil Cd content of 0 mg Kg-1, 5 mg Kg-1, and 50 mg Kg-1 respectively. Different letters within same column indicate significant difference among different treatments at P < 0.05, while same letters represent no significant difference.
英文摘要
Periphyton plays a significant role in heavy metal transfer in wetlands, but its contribution to cadmium (Cd) bioavailability in paddy fields remains largely unexplored.
The main aim of this study was to investigate the effect of periphyton on Cd behavior in paddy fields. Periphyton significantly decreased Cd concentrations in paddy waters.
Non-invasive micro-test technology analyses indicated that periphyton can absorb Cd from water with a maximum Cd2+ influx rate of 394 pmol cm−2 s−1 and periphyton intrusion significantly increased soil Cd concentrations.
However, soil Cd bioavailability declined significantly due to soil pH increase and soil redox potential (Eh) decrease induced by periphyton. With periphyton, more Cd was adsorbed and immobilized on organic matter, carbonates, and iron and manganese oxides in soil. Consequently, Cd content in rice decreased significantly.
These findings give insights into Cd biogeochemistry in paddy fields with periphyton, and may provide a novel strategy for reducing Cd accumulation in rice.
Indole derivatives derived from the secondary metabolites of marine organisms possess the excellent antifouling property to inhibit the biofouling. These compounds and their analogues are simple in structure and have been proven to have low toxicity and bioaccumulation. Therefore, the active indole antifoulants are expected to replace the potentially toxic antifoulants which are widely used in current antifouling coatings.
Seven indole derivatives were synthesized via the Friedel-Crafts alkylation reaction and were characterized by IR spectra, 1H NMR, 13C NMR and elemental analysis. Inhibition experiments against marine algae and bacteria were conducted, and the partial inhibition rates of algae and bacteria were more than 90%. This outcome indicates that indole derivatives possess excellent properties suitable for use as targeting anti-fouling compound for algae and bacteria. Non-invasive Micro-test Technology (NMT) reveals that the Ca2+ efflux of Platymonas subcordiformis dramatically increased in the presence of indole derivatives, which is inferred to be the molecular mechanism for inhibiting the growth of marine algae.
The antifouling coatings containing indole derivatives were prepared and subjected to an antifouling test in a marine environment, and the results show that N-(1-H-5-bromo-indole-3-ylmethyl) benzamide and N-(1-H-2-phenyl-indole-3-ylmethyl) benzamide possess better antifouling performance compared to copper pyrithione (CuPT). According to these results, indole derivatives in this study might become novel and promising antifoulants.
The interactions between metal and phytoplankton are affected by salinity in estuarine environments. While water chemistry is an important factor regulating the metal bioavailability in phytoplankton, the physiological adaptation of the algae cells may also change their intrinsic response to metals.
In this work, we tried to interpret the salinity-dependent Cd toxicity in a pennate diatom Nitzchia closterium from a biological side. As with many studies, we observed Cd toxicity to the diatom increased with decreasing salinity. However, changing free Cd ion concentrations may be partly responsible for the enhanced Cd toxicity.
Multiple evidences showed that diatom cells acclimated at low salinity had stronger intrinsic Cd adsorption capacity. Salinity significantly affected not only the nanostructures but also the biochemical composition in the cell surface of the diatom. Diatom cells grown at lower salinity had a lower surface potential, higher specific surface area, and more sulfur-containing groups in the cell wall, leading to stronger Cd binding capacity in the cells. Meanwhile, more Si was present as poly-silicic acid when the salinity decreased. The change of Si content and speciation in the cell wall are also considered a major reason for the variations of Cd surface binding.
Our study provided new clues for the salinity-dependent metal toxicity in marine diatoms.
Fig. 3. Cd2+ fluxes around the cell surface of the diatom P. tricornutum in the testing medium containing 8.9 μM Cd2+. (A) Instant net Cd2+ fluxes measured by a non-invasive microelectrode probe; (B) mean Cd2+ fluxes for the L-, M-, and H-Si cells. Means do not significantly differ (p>0.05) if they bear the same letter (n = 6). L, low; M, mid; H, high.
英文摘要
Marine phytoplankton possess a sophisticated homeostatic network to counteract metal toxicity. Changes in environmental conditions such as ambient nutrient concentrations can significantly impact their intrinsic metal sensitivity. In this study, we evaluated the role of silicon (Si) in counteracting cadmium (Cd) toxicity in the marine diatom Phaeodactylum tricornutum. We first demonstrated that Si enrichment dramatically enhanced Cd tolerance and changed the Cd accumulation in the diatom.
Our modeling suggested that Si-enriched cells adsorbed more Cd but had a higher Cd elimination rate than the Si-starved cells. Examinations by atomic force microscopy and X-ray photoelectron spectroscopy revealed that the Si-enriched cells had better silification andmore SiO- in the cell walls, which markedly lowered the surface potential of the diatom cells and allowed them to attract more Cd.
Although the Si-enriched cells tended to have a high Cd burden when facing Cd stress, they suppressed the increase of intracellular Cd by both down-regulating the influx transporter ZIP and up-regulating the efflux transporter ATPase5-1B.
Our study shows the significant roles Si plays in maintaining metal homeostasisand combating Cd challenge in marine diatoms.
为了研究菌丝尖端线粒体的呼吸活性,就需要一种高空间分辨率的氧流速测定方法。加拿大研究人员Roger R. Lew以粗糙脉孢菌(Neurospora crassa)为实验材料,运用非损伤微测技术结合显微技术研究了氰化物等处理后菌丝表面不同区域的氧流速变化。发现菌丝表面的氧内流(吸收)速率可被氰化物抑制,而交替氧化酶则可以恢复呼吸作用。菌丝尖端靠后10μm有个氧内流速率很大的区域,且氧内流的速率与菌丝的生长速率相关,而线粒体在菌丝体上富集的区域在距离尖端5~10μm处,与最大氧内流区域不同。因此,菌丝尖端的线粒体在生长发育的呼吸需求中所起的作用较小。
This study investigated the influences of cetyltrimethyl trimethyl ammonium chloride (CTAC), an emerging pollutant quaternary ammonium compound (QAC) in municipal effluents, on the transfer and uptake of NH4+ by Chlorella vulgaris F1068 cells removed EPS artificially (EPS-R) and coated EPS naturally (EPS-C) under different scenarios (e.g., the presence or absence of CTAC, different photoperiod sequences (light 12 h: dark 12 h or dark 12 h: light 12 h)).
The results showed that the removal of EPS increased the transfer and uptake of NH4+ but the presence of EPS caged NH4+ and effectively weakened the stress of CTAC (<0.5 mg/L) on NH4+ uptake. The main mechanism was considered that CTAC in the concentration range from 0.1 to 0.5 mg/L induced an increased amount of polysaccharide and protein in EPS and thus protected algal normal physiological functions (including cell membrane permeability and glutamine synthetase activity) from the damage of CTAC (0.1 to 0.5 mg/L) regardless of the photoperiod sequences.
Thereby, the findings of this study provided an insight into the role of algal EPS in transfer and uptake of nutrients under the coexisted toxics for the future algae-based sewage treatment application.
结果表明:在没有CTAC的6小时光照下,EPS-C细胞或EPS-R细胞的NH4+通量分别达到-1.87ng /(cm2·s)和-2.63ng /(cm2·s)。当添加0.5 mg / L的CTAC时,EPS-C或EPS-R细胞的NH4+通量急剧下降至-0.94 ng /(cm2·s)和-0.73 ng /(cm2·s)。相反,当EPS-R细胞和EPS-C细胞在黑暗中培养6小时无论CTAC存在与否,EPS-C细胞和EPS-R细胞的NH4+流速从负值转换为正值,表明NH4+从细胞内环境流出到培养基。
抑制HvNAT2降低了大麦对镉的耐受性。随后,研究使用两个RNAi株系(HvNAT2-RNAi1和HvNAT2-RNAi2)检测了HvNAT2的功能;与对照组相比,HvNAT2-RNAi1和HvNAT2-RNAi2中HvNAT2表达的降低导致Cd敏感表型;15 d Cd处理后,HvNAT2-RNAi系的茎干重平均降低了40.1%和55.3%,而GP的干重分别为22.0%和28.9%;HvNAT2 RNAi株系的根系Cd浓度和植株Cd积累均显著降低,但其根部向地上部的Cd转运率显著高于GP。
标题:TaWRKY70 positively regulates TaCAT5 enhanced Cd tolerance in transgenic Arabidopsis
作者:贵州大学任明见、贵州师范大学杜旭烨、Zhenzhen Jia、李木子
检测离子/分子指标Cd2+检测样品
拟南芥根分生区
中文摘要
WRKY转录因子(TFs)参与了植物对多种生物和非生物胁迫的响应;然而,WRKY TFs在小麦响应Cd胁迫中的调控作用仍然未知。本文研究了小麦TaWRKY70 TF在Cd胁迫下的机制。在拟南芥中表达TaWRKY70来进行功能分析。TaWRKY70通过Cd在根中积累而不是在叶片中积累来调节Cd耐受性。表达TaWRKY70后,拟南芥根系的Cd2+内流速率减少。定量实时荧光定量PCR(qRT-PCR)结果显示,Cd胁迫下,heavy metal ATPase (AtHMA3)、natural resistance-associatedmacrophage protein (AtNRAMP5)、 yellow stripe1-like (AtYSL3)、和iron transport protein (AtIRT1)的表达水平降低。转基因拟南芥的电解质渗漏率、丙二醛和过氧化氢含量均低于野生型,而抗氧化酶活性则高于野生型。电泳迁移率变化实验(EMSA)、酵母单杂实验(Y1H)和瞬时反式激活实验证明TaWRKY70可以直接结合到TaCAT5启动子上。本研究的发现为WRKY TFs参与重金属胁迫响应的提供了新的理解。
研究使用非损伤微测技术(NMT)测试了植物生长初期根尖中的Cd2+流速。BADH转基因株系中Cd2+的内流少于未经Cd处理的WT株系。0.5 mM CdCl2处理后,WT株系Cd2+外排,平均值为131.81 pmol cm-2s-1,BADH转基因株系Cd2+外排增强,平均值为188.60 pmol cm-2s-1(图1A, B)。结果表明,转基因植株比野生型植株具有更大的净Cd2+流速范围。为了研究Cd对其他离子流速的影响,研究检测了有无0.5 mM Cd处理下的烟草植物中净H+和K+流速的变化。在无Cd处理下,转基因植株和WT株系的净H+流速差异不大。然而,在0.5 mM CdCl2处理下,H+内流显著增加,且这种增加在转基因植株中更为明显(图1C, D)。在Cd胁迫下,BADH转基因株系和WT株系的K+流速曲线有明显的差异,K+的平均流速由内流变为外排,且WT株系中Cd胁迫诱导的K+外排速率大于转基因株系(图1E, F)。这些结果表明GB在Cd诱导下减少了K+外排,增强了Cd胁迫下烟草根部的H+内流。
标题:Comparative transcriptome combined with biochemical and physiological analyses provide new insights toward cadmium accumulation with two contrasting Nicotiana species
标题:Nitric Oxide Enhances Cytotoxicity of Lead by Modulating the Generation of Reactive Oxygen Species and Is Involved in the Regulation of Pb2+ and Ca2+ Fluxes in Tobacco BY-2 Cells
对照组:0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, pH 6.0 Cd处理组:0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, 0.05 mM CdCl2, pH 6.0
标题:Hemin-decreased cadmium uptake in pak choi (Brassica chinensis L.)seedlings is heme oxygenase-1 dependent and relies on its by-products ferrous iron and carbon monoxide
标题:Exogenous melatoninalleviates cadmium uptake and toxicity in apple rootstocks
作者:沈阳农业大学吕德国、何佳丽
检测离子/分子指标
Cd2+
检测样品
距根尖顶端300μm、600μm、1200μm、1500μm和3000μm的根表上的点
中文摘要(谷歌机翻)
为了检查褪黑素在苹果属植物中对Cd吸收,积累和排毒的潜在作用,我们将两种在Cd吸收和积累方面差异很大的苹果砧木暴露于0或30μMCd和0或100μM褪黑素。与耐镉的微小苹果花青霉菌“青州林琴”相比,耐镉的baccata对镉胁迫的内源性褪黑激素产生的刺激程度更大。褪黑素的应用减弱了镉诱导的生长,光合作用和酶活性以及ROS和MDA积累的减少。褪黑素处理比镉胁迫的巴塔卡巴氏菌更有效地恢复了镉对微苹果念珠菌青州林琴的光合作用,光合色素和生物量的恢复。外源性褪黑素降低了根部对镉的2+吸收,降低了叶片的镉含量两种暴露于镉的砧木中的镉积累,降低的镉转运因子(T f s)s和增加的根,茎和叶褪黑素含量s。褪黑素的应用增加了抗氧化剂的浓度和酶的活性,以清除Cd诱导的ROS。外源性褪黑素处理改变了调节Cd吸收,转运和排毒的几种基因的mRNA水平,包括HA7,NRAMP1,NRAMP3 HMA4,PCR2,NAS1,MT2, ABCC1和MHX。综上所述,这些结果表明,外源褪黑素减少了苹果属植物中的空中部分Cd积累并减轻了Cd毒性,这可能是由于褪黑激素介导的Cd在组织中的分配以及抗氧化防御系统的诱导以及转录过程中涉及排毒的关键基因的诱导。
为了更好地了解Na+和K+的动态变化,使用非损伤微测技术(NMT)来监测转基因和WT水稻根尖的Na+和K+流速。100 mM NaCl处理1 h后,所有测试的幼苗均显示出Na+外排。Na+在转基因水稻中的外排速率远高于WT(图1a)。同时,转基因水稻幼苗显示出K+内流,野生稻幼苗显示出K+外排(图1b)。因此,TaPUB15-D在水稻中的过表达明显增加了在盐胁迫下保K+和排Na+的能力。较低的Na+/K+比值确保转基因植株在高盐度条件下具有更好的耐盐性。
其他实验结果
3个TaPUB15同源基因均高度保守。TaPUB15-D定位在细胞核和细胞质中。TaPUB15在幼苗根系表达量最高,其次是幼苗叶片、抽穗期根系和萌发期和幼苗期的根基部。在抽穗的节、茎和旗叶中表达量最低。在250 mM NaCl、50 μM ABA和4°C低温处理下,TaPUB15被强烈激活,但在16.1% PEG处理下TaPUB15被激活程度较低。TaPUB15-D过表达导致转基因水稻的根更长、更多。TaPUB15-D在水稻中的过表达增强了其耐盐性。转基因株系中OsP5CS1的转录水平与WT相比增加了近4倍。钾转运基因OsHKT1;1的表达被盐胁迫显著诱导。TaPUB15-D的过表达减少了Na+的积累,使水稻转基因株系在盐碱条件下保持相对较低的Na+/K+比值。TaPUB15-D的过表达增强了转基因拟南芥的耐盐性。
在对照条件下,野生型和cyp86a1突变体的根中有净Na+内流,但在50 mM NaCl处理下,净Na+流速转为外排(图1a-b)。当用50 mM NaCl处理时,cyp86a1突变体根中的净Na+外排比野生型根中的Na+外排显着降低了38.5%(图1b)。没有NaCl处理时,野生型和cyp86a1均存在净K+内流,尽管cyp86a1根中的K+内流速率比野生型低(图1c-d)。NaCl处理在野生型和cyp86a1根中均引起K+外排,但加入50 mM NaCl后,cyp86a1根中的净K+外排量比野生型中的K+外排量高1.96倍(图1c-d)。
标题:The SNARE protein LbSYP61 participates in salt secretion in Limonium bicolor
作者:山东师范大学戎均康、王宝山、陈敏、Chaoxia Lu
检测离子/分子指标
Na+
检测样品
二色补血草第六个叶片
中文摘要(谷歌机翻)
土壤盐渍化是一个全球性问题,抑制了植物的生长并限制了作物的产量。盐生植物通过盐腺分泌过量的盐,从而避免了盐在其细胞内的过度积累,并保护了自己免受盐相关损害的伤害。但是,尚不清楚通过盐腺分泌盐的分子机制。在这里,我们使用布雷菲德菌素A(BFA),一种高尔基体介导的细胞分泌的特异性抑制剂,通过叶盘法和非侵入式测微法检测双色网状嗜盐菌柠檬酸中囊泡运输是否参与盐的分泌。实际上,在200μg/ ml BFA处理后,盐腺中的盐分泌被显着抑制,盐腺中的高尔基体被破坏,酸性磷酸酶活性被显着抑制。为了进一步检查囊泡运输在盐分泌中的作用,我们使用病毒诱导的基因沉默(VIGS)下调编码反式高尔基体定位的可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体(SNARE)蛋白LbSYP61的基因。使LbSYP61沉默后,双色乳杆菌通过盐腺分泌盐的能力也显着降低。这些结果提供了直接的证据,表明水泡运输通过盐腺参与了盐的分泌,而水泡运输相关蛋白LbSYP61在此过程中起着重要作用。
离子/分子流实验处理方法
Control: 霍格兰营养液培养28 d (0 mM NaCl)
NaCl: 200 mM NaCl
NaCl + DMSO(二甲基亚砜): 200 mMNaCl + 4% DMSO
NaCl + BFA(布雷菲德菌素): 200 mM NaCl +200 μg/ml BFA
NaCl – BFA: NaCl + BFA-treated samples transferred to 200 mM NaCl without BFA
离子/分子流结果
为了进一步证实200μg/mL BFA能显著抑制盐腺的分泌活性,采用NMT技术直接测定了二色补血草叶表皮单个盐腺的Na+分泌速率。在用200mM NaCl处理的叶片后,单个盐腺体的Na+分泌速率增加到对照的28.5倍左右。4% DMSO处理对Na+分泌率无影响,但添加BFA使Na+分泌速率仅为200mM NaCl溶液处理的5.8%。将经BFA处理的叶子转移至不含BFA的200 mM NaCl中,Na+分泌率显著增加,达到200mM NaCl处理的44.7%。因此,囊泡抑制剂BFA可逆地影响盐腺的盐分泌。
其他实验结果
BFA明显抑制盐分泌。分泌液中酸性磷酸酶活性的丧失进一步表明盐的分泌是通过囊泡转运发生的。BFA引起盐腺细胞器的超微结构改变。LbSYP61在200 mM NaCl处理下相对表达变化最大。 LbSYP61是一种典型的高度保守的Qc-SNARE蛋白。LbSYP61基因敲除导致盐分泌减少。
在用50 mM NaCl处理的根中,低氧导致rbohD突变体根部的净Na+和Cl-吸收瞬时增加(图2)。除了成熟区低氧诱导的Na+吸收外,WT根中没有观察到这种效应(图2B)。WT根中的净Na+内流量也显著低于rbohD突变体(图2B)。在这两个区域中,没有测量到对低氧处理响应的净K+流速的显著变化(图3A,B),并且低氧胁迫的开始引起了两个区域向瞬时净Ca2+流出的转变(图3C,D),两个基因型之间没有显着差异。然而,盐胁迫48h后,WT比rbohD突变体在伸长区有更多的Ca2+内流(图3C)。
中国林科院亚热带林业研究所卓仁英研究员课题组在Environmental and Experimental Botany上发表了一篇文章,题目为“Pathogenesis-related protein PR10 fromSalix matsudanaKoidz exhibits resistance to salt stress intransgenicArabidopsis thaliana”,主要探究PR蛋白在植物耐盐机制中起到的作用。
前期的比较蛋白质组学分析表明:沙柳PR蛋白(SmPR10)较为丰富,经过100 mM NaCl处理后表达上调。本实验以沙柳为材料,克隆并鉴定了SmPR10基因,以验证其在耐盐性中的作用。SmPR10的氨基酸序列与紫苏柳和毛白杨的PR蛋白的序列同源性分别为98%和93%。SmPR10定位在拟南芥原生质体的胞质中,根的转录及蛋白水平较高,且100mM NaCl处理后表达上调。免疫定位分析发现,韧皮部纤维细胞和根木质部中特异性的检测到SmPR10。而且,SmPR10的异质过表达提高了转基因拟南芥的耐盐性,具体表现在根长度、根数量、Na+流速、以及叶绿素含量、MDA含量、电导率等生理参数及SOD和POD酶活性水平。
Fig.3–Flux profiles of Na+, K+and Ca2+in roottip elongation zones of 7-day-oldrice seedlings. (a)Net Na+fluxes under favorable culture. (b) Net Na+fluxes under culture with a 120 mmol·L-1NaCl solution. (c) Net K+fluxes under favorable culture. (d) Net K+fluxes under salt stress.(e) Net Ca2+fluxes under favorable culture. (f) Net Ca2+fluxes under culture with a solution of 120 mmol·L-1 NaCl. Net effluxes areindicated by positive and net influxes by negative values. (g) Mean Na+flux. (g) Mean K+flux. (i) Mean Ca2+flux. WT, wildtype.
然后,我们研究了在褪黑素(Mel)预处理的根中瞬时NaCl处理的K+流速动力学。向容器中添加100 mM NaCl会导致水稻植物的伸长区和成熟根区大量的K+流出(图2a,c)。根区之间的K+流出量显着不同,其中伸长区中的K+流出量比成熟区中的K+流出量高一个数量级。与非褪黑素预处理(Mock)相比,褪黑素预处理显着降低了两个根部区域的盐诱导的K+流出(图2)。未经处理的根,伸长和成熟根区的平均K+流出值分别为1,529和205 nmol m-2s-1,而经过预处理的根,分别为632和78 nmol m-2s-1。所有这些结果表明,褪黑激素能够使水稻根部更好地保留K+,其中主要作用是在伸长区中观察到。
为了评估褪黑素对氧化胁迫下根系反应的影响,测量了10 mM H2O2和羟基自由基(由Cu/A混合物生成)处理前后根伸长区的瞬时K+和Ca2+流速。在伸长区,外源Cu/A(0.3/1mM)诱导大量K+外流(图3b);用褪黑素预处理的根使其减少了近3倍。Mel预处理的根和Mock对照对10mMH2O2处理的反应无显著性差异(图3a)。
ROS引发的K+跨质膜(PM)外流通常伴随着植物根部的Ca2+内流,这种ROS诱导的Ca2+吸收量与小麦和大麦的耐盐性呈负相关。因此,我们测量了PM-Ca2+渗透通道对10mM H2O2和Cu/A的敏感性(图3)。结果反映了K+流速的结果(图5c,d)。两种处理均引起根伸长区瞬时净Ca2+吸收。褪黑素预处理已使根Ca2+渗透性离子通道对羟基自由基显着脱敏(Cu / A处理;图3d),而对10 mM H2O2处理的反应没有显著差异(图3c)。
我们进一步表明,在盐碱条件下,Ca2 +结合到ZmNSA1的EF-手结构域,然后通过26S蛋白酶体触发其降解,这反过来又增加了PM-H + -ATPases(MHA2和MHA4)的转录水平。增强SOS1 Na + / H +反转运蛋白介导的根Na +外排。
我们的研究揭示了Ca2 +触发的盐碱耐受性的机制,并为选育耐盐碱玉米品种提供了重要的基因靶标。
英文摘要
Sodium (Na+) toxicityis one of the major damages imposed on crops by saline-alkaline stress.
Here we show thatnatural maize inbred lines display substantial variations in shoot Na+ contentsand saline-alkaline (NaHCO3) tolerance, and reveal that ZmNSA1 (Na+ Contentunder Saline-Alkaline Condition) confers shoot Na+ variations under NaHCO3condition by a genome-wide association study. Lacking of ZmNSA1 promotes shootNa+ homeostasis by increasing root Na+ efflux. A naturally occurred 4-bpdeletion decreases the translation efficiency of ZmNSA1 mRNA, thus promotes Na+homeostasis.
We further show that,under saline-alkaline condition, Ca2+ binds to the EF-hand domain of ZmNSA1then triggers its degradation via 26S proteasome, which in turn increases thetranscripts levels of PM-H+-ATPases (MHA2 and MHA4), and consequently enhancesSOS1 Na+/H+ antiportermediated root Na+ efflux.
Our studies reveal themechanism of Ca2+-triggered saline-alkaline tolerance and provide an importantgene target for breeding saline-alkaline tolerant maize varieties.
标题:Arabidopsis transcription factor WRKY8 functions antagonistically with its interacting partner VQ9 to modulate salinity stress tolerance
影响因子:6.582
检测指标:K+流速
作者:中科院西双版纳热带植物园余迪求、胡彦如
英文摘要
The WRKY transcription factors have been demonstrated to play crucial roles in regulating stress responses; however, the exact mechanisms underlying their involvement in stress responses are not fully understood.
Arabidopsis WRKY8 was predominantly expressed in roots and was highly upregulated by salt treatment. Disruption of WRKY8 rendered plants hypersensitive to salt, showing delayed germination, inhibited post‐germination development and accelerated chlorosis. Further investigation revealed that WRKY8 interacted with VQ9, and their interaction decreased the DNA‐binding activity of WRKY8.
The VQ9 protein was exclusively localized in the nucleus, and VQ9 expression was strongly responsive to NaCl treatment. Mutation of VQ9 enhanced tolerance to salt stress, indicating that VQ9 acts antagonistically with WRKY8 to mediate responses to salt stress. The antagonist functions of WRKY8 and VQ9 were consistent with an increased or reduced Na+/K+ concentration ratio, as well as contrasting expression patterns of downstream stress‐responsive genes in salt‐stressed wrky8 and vq9 mutants.
Moreover, chromatin immunoprecipitation (ChIP) assays showed that WRKY8 directly bound the promoter of RD29A under salt conditions. These results provided strong evidence that the VQ9 protein acts as a repressor of the WRKY8 factor to maintain an appropriate balance of WRKY8‐mediated signaling pathways to establish salinity stress tolerance.
标题:Progress in Understanding the Physiological and Molecular Responses of Populus to Salt Stress
影响因子:4.183
作者:广西农科院、中科院昆明植物所
英文摘要
Salt stress (SS) has become an important factor limiting afforestation programs. Because of their salt tolerance and fully sequenced genomes, poplars (Populus spp.) are used as model species to study SS mechanisms in trees. Here, we review recent insights into the physiological and molecular responses of Populus to SS, including ion homeostasis and signaling pathways, such as the salt overly sensitive (SOS) and reactive oxygen species (ROS) pathways. We summarize the genes that can be targeted for the genetic improvement of salt tolerance and propose future research areas.
标题:Potassium Transporter LrKUP8 Is Essential for K+ Preservation in Lycium ruthenicum, A Salt-Resistant Desert Shrub
影响因子:3.331
检测指标:K+流速
检测样品:黒枸杞愈伤组织
K+流实验处理方法:
有/无300 mM NaCl培养12h
K+流实验测试液成份: 0.5 mM KCl, 0.5 mM NaCl, 0.1mM MgCl2, 0.2 mM CaCl2, 2.5% sucrose,pH 5.7
作者:北京林业大学陈金焕、戴逢斌
英文摘要
Salt stress is a major constraint for many crops and trees. A wild species of Goji named Lycium ruthenicum is an important economic halophyte in China and has an extremely high tolerance to salinity. L. ruthenicum grows in saline soil and is known as a potash-rich species.
However, its salt adaptation strategies and ion balance mechanism remains poorly understood. Potassium (K+) is one of the essential macronutrients for plant growth and development. In this study, a putative salt stress-responsive gene encoding a HAK (high-affinity K+)/KUP (K+ uptake)/KT (K+ transporter) transporter was cloned and designated as LrKUP8.
This gene belongs to the cluster II group of the KT/HAK/KUP family. The expression of LrKUP8 was strongly induced under high NaCl concentrations. The OE-LrKUP8 calli grew significantly better than the vector control calli under salt stress conditions. Further estimation by ion content and micro-electrode ion flux indicated a relative weaker K+ efflux in the OE-LrKUP8 calli than in the control.
Thus, a key gene involved in K+ uptake under salt condition was functionally characterized using a newly established L. ruthenicum callus transformation system. The importance of K+ regulation in L. ruthenicum under salt tolerance was highlighted.
Plants have evolved complex mechanisms that allow them to withstand multiple environmental stresses, including biotic and abiotic stresses.
Here, we investigated the interaction between herbivore exposure and salt stress of Ammopiptanthus nanus, a desert shrub. We found that jasmonic acid (JA) was involved in plant responses to both herbivore attack and salt stress, leading to an increased NaCl stress tolerance for herbivore-pretreated plants, and increase in K+/Na+ ratio in roots. Further evidence revealed the mechanism by which herbivore improved plant NaCl tolerance. Herbivore pretreatment reduced K+ efflux and increased Na+ efflux in plants subjected to long-term, short-term, or transient NaCl stress.
Moreover, herbivore pretreatment promoted H+ efflux by increasing plasma membrane H+-ATPase activity. This H+ efflux creates a transmembrane proton motive force that drives the Na+/H+ antiporter to expel excess Na+ into the external medium. In addition, high cytosolic Ca2+ was observed in the roots of herbivore-treated plants exposed to NaCl, and this effect may be regulated by H+-ATPase.
Taken together, herbivore exposure enhances A. nanus tolerance to salt stress by activating the JA signalling pathway, increasing plasma membrane H+-ATPase activity, promoting cytosolic Ca2+ accumulation, and then restricting K+ leakage and reducing Na+ accumulation in the cytosol.
2011年11月25日,山东省农科院董合忠、孔祥强利用NMT在Journal of Experimental Botany 上发表了标题为Effects of non-uniform root zone salinity on water use Na+ recirculation, and Na+ and H+ flux in cotton的研究成果。
期刊:Journal of Experimental Botany
主题:根系不均一盐胁迫提升植物水分利用率的机制
标题:Effects of non-uniform root zone salinity on water use Na+ recirculation, and Na+ and H+ flux in cotton
影响因子:4.818
检测指标:Na+、H+流速
作者:山东省农科院董合忠、孔祥强
英文摘要
A new split-root system was established through grafting to study cotton response to non-uniform salinity. Each root half was treated with either uniform (100/100 mM) or non-uniform NaCl concentrations (0/200 and 50/150 mM).
In contrast to uniform control, non-uniform salinity treatment improved plant growth and water use, with more water absorbed from the non- and low salinity side. Non-uniform treatments decreased Na+ concentrations in leaves. The [Na+] in the ‘0’ side roots of the 0/200 treatment was significantly higher than that in either side of the 0/0 control, but greatly decreased when the ‘0’ side phloem was girdled, suggesting that the increased [Na+] in the ‘0’ side roots was possibly due to transportation of foliar Na+ to roots through phloem.
Plants under non-uniform salinity extruded more Na+ from the root than those under uniform salinity. Root Na+ efflux in the low salinity side was greatly enhanced by the higher salinity side. NaCl-induced Na+ efflux and H+ influx were inhibited by amiloride and sodium orthovanadate, suggesting that root Na+ extrusion was probably due to active Na+/H+ antiport across the plasma membrane.
Improved plant growth under non-uniform salinity was thus attributed to increased water use, reduced leaf Na+ concentration, transport of excessive foliar Na+ to the low salinity side, and enhanced Na+ efflux from the low salinity root.
2017年11月18日,三峡大学何正权、中国林业科学研究院亚热带林业研究所邱文利用NMT在Environmental and Experimental Botany 上发表了标题为Overexpression of cysteine protease gene from Salix matsudana enhances salt tolerance in transgenic Arabidopsis的研究成果。
期刊:Environmental and Experimental Botany
主题:松柳半胱氨酸蛋白酶基因的过表达增强了转基因拟南芥的耐盐性
标题:Overexpression of cysteine protease gene from Salix matsudana enhances salt tolerance in transgenic Arabidopsis
影响因子:4.369
检测指标:Na+、H+流速
作者:三峡大学何正权、中国林业科学研究院亚热带林业研究所邱文
英文摘要
Salix matsudana is a salt-tolerant arbor tree species. We are interested in understanding its mechanisms of salt-tolerance.
Here, we isolated a full-length 1080-bp cDNA for a salt stress-responsive cysteine protease gene from S. matsudana, designated SmCP. The deduced 359-amino-acid SmCP protein was essentially identical to cysteine proteases of other plant species and was predicted to contain inhibitor-I29 and peptidase-C1A domains with three active catalytic sites found in eukaryotic cysteine proteases.
Expression profile analysis revealed that SmCP expression is constitutive and overexpression in roots takes place under salt stress. Expression of SmCP in Escherichia coli cells led to enhanced salinity tolerance. In addition, transgenic Arabidopsis thaliana lines overexpressing SmCP displayed enhanced tolerance to salt stress, with increased germination rates, antioxidant enzyme (superoxide dismutase) activity, chlorophyll content and ion flux in the root, and reduced malondialdehyde (MDA) levels and electric conductivity compared with control plants.
These results indicate that SmCP likely plays an important role in salt tolerance in S. matsudana.
中文摘要(谷歌机翻)
柳柳是耐盐的乔木树种。我们有兴趣了解其耐盐性机制。
在这里,我们从S. matsudana,命名为SmCP的盐胁迫响应半胱氨酸蛋白酶基因中分离出全长1080 bp cDNA。推导的359个氨基酸的SmCP蛋白与其他植物物种的半胱氨酸蛋白酶基本相同,并且预计包含在真核半胱氨酸蛋白酶中具有三个活性催化位点的抑制剂I29和肽酶C1A域。
2012年11月02日,河北师范大学崔素娟、王鹏利用NMT在Journal of Biological Chemistry 上发表了标题为A Na+ Ca2+ exchanger-like protein (AtNCL) involved in salt stress in Arabidopsis 的研究成果。
2016年11月02日,浙江大学李廷强、陶琦利用NMT在Journal of Experimental Botany 上发表了标题为The apoplasmic pathway via the root apex and lateral roots contributes to Cd hyperaccumulation in the hyperaccumulator Sedum alfredii的研究成果。
期刊:Journal of Biological Chemistry
主题:Na+ Ca2+交换蛋白样蛋白(AtNCL)参与拟南芥的盐胁迫
标题:A Na+ Ca2+ exchanger-like protein (AtNCL) involved in salt stress in Arabidopsis
影响因子:4.773
检测指标:Ca2+流速
作者:河北师范大学崔素娟、王鹏
英文摘要
Calcium ions (Ca2+) play a crucial role in many key physiological processes; thus, the maintenance of Ca2+ homeostasis is of primary importance. Na+/Ca2+ exchangers (NCXs) play an important role in Ca2+ homeostasis in animal excitable cells.
Bioinformatic analysis of the Arabidopsis genome suggested the existence of a putative NCX gene, Arabidopsis NCX-like (AtNCL), encoding a protein with an NCX-like structure and different from Ca2+/H+ exchangers and Na+/H+ exchangers previously identified in plant. AtNCL was identified to localize in the Arabidopsis cell membrane fraction, have the ability of binding Ca2+, and possess NCX-like activity in a heterologous expression system of cultured mammalian CHO-K1 cells. AtNCL is broadly expressed in Arabidopsis, and abiotic stresses stimulated its transcript expression.
Loss-of-function atncl mutants were less sensitive to salt stress than wild-type or AtNCL transgenic overexpression lines. In addition, the total calcium content in whole atncl mutant seedlings was higher than that in wild type by atomic absorption spectroscopy. The level of free Ca2+ in the cytosol and Ca2+ flux at the root tips of atncl mutant plants, as detected using transgenic aequorin and a scanning ion-selective electrode, required a longer recovery time following NaCl stress compared with that in wild type.
All of these data suggest that AtNCL encodes a Na+/Ca2+ exchanger-like protein that participates in the maintenance of Ca2+ homeostasis in Arabidopsis. AtNCL may represent a new type of Ca2+ transporter in higher plants.
标题:The apoplasmic pathway via the root apex and lateral roots contributes to Cd hyperaccumulation in the hyperaccumulator Sedum alfredii
影响因子:5.354
检测指标:Cd2+流速
作者:浙江大学李廷强、陶琦
英文摘要
Although the significance of apoplasmic barriers in roots with regards to the uptake of toxic elements is generally known, the contribution of apoplasmic bypasses (ABs) to cadmium (Cd) hyperaccumulation is little understood.
Here, we employed a combination of stable isotopic tracer techniques, an ABs tracer, hydraulic measurements, suberin lamellae staining, metabolic inhibitors, and antitranspirants to investigate and quantify the impact of the ABs on translocation of Cd to the xylem in roots of a hyperaccumulating (H) ecotype and a non-hyperaccumulating (NH) ecotype of Sedum alfredii.
In the H ecotype, the Cd content in the xylem sap was proportional to hydrostatic pressure, which was attributed to pressure-driven flow via the ABs. The contribution of the ABs to Cd transportation to the xylem was dependent on the Cd concentration applied to the H ecotype (up to 37% at the highest concentration used). Cd-treated H ecotype roots showed significantly higher hydraulic conductance compared with the NH ecotype (76 vs 52 × 10–8 m s–1MPa–1), which is in accordance with less extensive suberization due to reduced expression of suberin-related genes.
The main entry sites of apoplasmically transported Cd were localized in the root apexes and lateral roots of the H ecotype, where suberin lamellae were not well developed. These findings highlight the significance of the apoplasmic bypass in Cd hyperaccumulation in hyperaccumulating ecotypes of S. alfredii.
在H型生态系统中,木质部汁液中的Cd含量与静水压力成正比,这归因于通过AB的压力驱动流。 AB对Cd向木质部运输的贡献取决于应用于H生态型的Cd浓度(使用最高浓度时高达37%)。与NH生态型相比,Cd处理的H生态型根系显示出更高的水力传导性(76 vs 52×10–8 m s–1MPa-1),这与由于suberin相关基因表达减少而引起的泛化作用减弱有关。
标题:Root-zone-specific sensitivity of K+-and Ca2+-permeable channels to H2O2 determines ion homeostasis in salinized diploid and hexaploid Ipomoea trifida
K+、H+、Ca2+、Na+流速流实验测试液成份: H+/K+/Ca2+瞬时:0.1 mM NaCl, 0.1 mM MgCl2,0.1 mM CaCl2, and 0.5 mM KCl at pH 5.7 K+:150 mM NaCl, 0.1 mM MgCl2, 0.1 mM CaCl2, and 0.5 mM KCl, pH 5.7
作者:江苏师范大学孙健、李宗芸
英文摘要
Polyploids generally possess superior K+/Na+ homeostasis under saline conditions compared with their diploid progenitors.
In this study, we identified the physiological mechanisms involved in the ploidy-related mediation of K+/Na+ homeostasis in the roots of diploid (2x) and hexaploid (6x; autohexaploid) Ipomoea trifida, which is the closest relative of cultivated sweet potato. Results showed that 6x I. trifida retained more K+ and accumulated less Na+ in the root and leaf tissues under salt stress than 2x I. trifida.
Compared with its 2x ancestor, 6x I. trifida efficiently prevents K+ efflux from the meristem root zone under salt stress through its plasma membrane (PM) K+-permeable channels, which have low sensitivity to H2O2. Moreover, 6x I. trifida efficiently excludes Na+ from the elongation and mature root zones under salt stress because of the high sensitivity of PM Ca2+-permeable channels to H2O2.
Our results suggest the root-zone-specific sensitivity to H2O2 of PM K+- and Ca2+-permeable channels in the co-ordinated control of K+/Na+ homeostasis in salinized 2x and 6x I. trifida. This work provides new insights into the improved maintenance of K+/Na+ homeostasis of polyploids under salt stress.
中文摘要(谷歌机翻)
与二倍体祖细胞相比,多倍体在盐水条件下通常具有优越的K+ / Na+稳态。
在这项研究中,我们确定了与二倍体(2x)和六倍体(6x;自六倍体)Tripoda的根的K+/ Na+稳态的倍性相关介导有关的生理机制,这是栽培红薯的近亲。结果表明,与2x I. trifida相比,在盐胁迫下6x I. trifida保留更多的K +并在根和叶组织中积累较少的Na+。
与2x祖先相比,6x裂叶线虫通过其对H2O2敏感性低的质膜(PM)K+渗透通道有效地防止了盐胁迫下分生组织根区的K+流出。此外,由于PM Ca2+的可渗透通道对H2O2的敏感性高,因此6x I. trifida有效地将Na+从盐胁迫下的伸长和成熟根区中排除。
NO3-流速流实验测试液成份: NO3- measuring solution: 0.1 mM KNO3, 0.1 mM KCl, 0.1 mM CaCl2, pH 5.3 was adjusted with KOH and HCl. H+ measuring solution: 0.1 mM NaCl, 0.1 mM MgCl2, 0.1 mM CaCl2 and 0.5 mM KCl, pH 5.3 was adjusted with KOH and HCl.
作者:北京林业大学陈少良、撒刚、邓晨
英文摘要
Salt stress is an important environmental cue impeding poplar nitrogen nutrition. Here, we characterized the impact of salinity on proton‐driven nitrate fluxes in ectomycorrhizal roots and the importance of a Hartig net for nitrate uptake.
We employed two Paxillus involutus strains for root colonization: MAJ, which forms typical ectomycorrhizal structures (mantle and Hartig net), and NAU, colonizing roots with a thin, loose hyphal sheath. Fungus‐colonized and noncolonized Populus × canescens were exposed to sodium chloride and used to measure root surface pH, nitrate (NO3−) flux and transcription of NO3− transporters (NRTs; PcNRT1.1, ‐1.2, ‐2.1), and plasmalemma proton ATPases (HAs; PcHA4, ‐8, ‐11).
Paxillus colonization enhanced root NO3− uptake, decreased surface pH, and stimulated NRTs and HA4 of the host regardless the presence or absence of a Hartig net. Under salt stress, noncolonized roots exhibited strong net NO3− efflux, whereas beneficial effects of fungal colonization on surface pH and HAs prevented NO3− loss. Inhibition of HAs abolished NO3− influx under all conditions.
We found that stimulation of HAs was crucial for the beneficial influence of ectomycorrhiza on NO3− uptake, whereas the presence of a Hartig net was not required for improved NO3− translocation. Mycorrhizas may contribute to host adaptation to salt‐affected environments by keeping up NO3− nutrition.
2012年9月21日,中科院南京土壤研究所施卫明、张建华、许卫锋利用NMT在Journal of Experimental Botany上发表了标题为PIN2 is required for the adaptation of Arabidopsis roots to alkaline stress by modulating proton secretion的研究成果。
期刊:Journal of Experimental Botany
主题:PIN2调节碱胁迫下质子分泌
标题:PIN2 is required for the adaptation of Arabidopsis roots to alkaline stress by modulating proton secretion
Soil alkalinity is a widespread environmental problem that limits agricultural productivity. The hypothesis that an auxin-regulated proton secretion by plasma membrane H+-ATPase plays an important role in root adaption to alkaline stress was studied. It was found that alkaline stress increased auxin transport and PIN2 (an auxin efflux transporter) abundance in the root tip of wild-type Arabidopsis plants (WT).
Compared with WT roots, the pin2 mutant roots exhibited much reduced plasma membrane H+-ATPase activity, root elongation, auxin transport, and proton secretion under alkaline stress. More importantly, roots of the pks5 mutant (PKS5, a protein kinase) lacking PIN2 (a pks5/pin2 double mutant) lost the previous higher proton-secretion capacity and higher elongation rate of primary roots under alkaline stress.
By using Arabidopsis natural accessions with a high proton-secretion capacity, it was found that their PIN2 transcription abundance is positively related to the elongation rate of the primary root and proton-secretion capacity under alkaline stress.
Taken together, our results confirm that PIN2 is involved in the PKS5-mediated signalling cascade under alkaline-stress and suggest that PIN2 is required for the adaptation of roots to alkaline stress by modulating proton secretion in the root tip to maintain primary root elongation.
2018年9月19日,北京林业大学陈少良、林善枝、赵楠、孙健利用NMT在Frontiers in Plant Science上发表了标题为Hydrogen Sulfide Mediates K+ and Na+ Homeostasis in the Roots of Salt-Resistant and Salt-Sensitive Poplar Species Subjected to NaCl Stress的研究成果。
期刊:Frontiers in Plant Science
主题:硫化氢介导盐胁迫和盐敏感杨树种根系中的K+和Na+稳态
标题:Hydrogen Sulfide Mediates K+ and Na+ Homeostasis in the Roots of Salt-Resistant and Salt-Sensitive Poplar Species Subjected to NaCl Stress.
0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.2 mM Na2SO4, and 0.3 mM MES, pH 4.0
作者:北京林业大学陈少良、林善枝、赵楠、孙健
英文摘要
Non-invasive micro-test techniques (NMT) were used to analyze NaCl-altered flux profiles of K+, Na+, and H+ in roots and effects of NaHS (a H2S donor) on root ion fluxes in two contrasting poplar species, Populus euphratica (salt-resistant) and Populus popularis (salt-sensitive).
Both poplar species displayed a net K+ efflux after exposure to salt shock (100 mM NaCl), as well as after short-term (24 h), and long-term (LT) (5 days) saline treatment (50 mM NaCl, referred to as salt stress). NaHS (50 μM) restricted NaCl-induced K+ efflux in roots irrespective of the duration of salt exposure, but K+ efflux was not pronounced in data collected from the LT salt stress treatment of P. euphratica.
The NaCl-induced K+ efflux was inhibited by a K+ channel blocker, tetraethylammonium chloride (TEA) in P. popularis root samples, but K+ loss increased with a specific inhibitor of plasma membrane (PM) H+-ATPase, sodium orthovanadate, in both poplar species under LT salt stress and NaHS treatment. This indicates that NaCl-induced K+ loss was through depolarization-activated K+ channels. NaHS caused increased Na+ efflux and a corresponding increase in H+ influx for poplar roots subjected to both the short- and LT salt stress.
The NaHS-enhanced H+ influx was not significant in P. euphratica samples subjected to short term salt stress. Both sodium orthovanadate and amiloride (a Na+/H+ antiporter inhibitor) effectively inhibited the NaHS-augmented Na+ efflux, indicating that the H2S-enhanced Na+ efflux was due to active Na+ exclusion across the PM. We therefore conclude that the beneficial effects of H2S probably arise from upward regulation of the Na+/H+ antiport system (H+ pumps and Na+/H+ antiporters), which promote exchange of Na+ with H+ across the PM and simultaneously restricted the channel-mediated K+ loss that activated by membrane depolarization.
NH4+: 0.1 mM NH4NO3, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
NO3-: 0.1 mM NH4NO3, 1.0 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
作者:山东农业大学林学院马风云、刘秀梅
英文摘要
A potted experiment with Populus × euramericana ‘Neva’ was carried out to assess whether there are positive effects of magnetic treatment of saline water (MTSW) on nitrogen metabolism under controlled conditions in a greenhouse.
Growth properties, nitrogen contents, enzyme activities and metabolite concentrations were determined based on field experiments and laboratory analysis after a 30-day treatment.
The results were as follows: (1) Biomass accumulation, root morphological properties and total nitrogen content were improved by MTSW. (2) Magnetization led to a greater increase in nitrate-nitrogen (NO3−-N) content in roots than in leaves, accompanied by greater NO3− efflux and activated nitrate reductase. (3) MTSW led to a higher ammonium-nitrogen (NH4+-N) content and greater uptake of net NH4+ in the leaves than that in the roots. (4) Magnetization stimulated glutamine synthase, glutamate dehydrogenase and glutamate synthase activities, whereas the concentrations of glutathione and oxidized glutathione were increased in leaves but decreased in roots, and the total glutathione content was increased.
Overall, these results indicated some beneficial impacts of MTSW on nitrogen translocation under field conditions, especially for equilibrating the distribution of NO3−-N and NH4+-N. Moreover, these findings confirmed the potential of using low-quality water for agriculture.
2013年8月19日,厦门大学郑海雷、陈娟利用NMT在PLoS ONE上发表了标题为Nitric Oxide Mediates Root K+/Na+ Balance in a Mangrove Plant, Kandelia obovata, by Enhancing the Expression of AKT1-Type K+ Channel and Na+/H+ Antiporter under High Salinity的研究成果。
期刊:PLoS ONE
主题:NO调控红树耐盐机制
标题:Nitric Oxide Mediates Root K+/Na+ Balance in a Mangrove Plant, Kandelia obovata, by Enhancing the Expression of AKT1-Type K+ Channel and Na+/H+ Antiporter under High Salinity
影响因子:3.730
检测指标:Na+,K+流速
检测部位:红树根(距离根尖20mm)
Na+,K+流实验处理方法:
红树幼苗,400mM NaCl/100mM SNP/400mM NaCl+100mM SNP处理15天,100 mM阿米洛利/500 mM钒酸盐/200 mM cPTIO瞬时处理
Na+,K+流实验测试液成份:
0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2,0.5 mM NaCl, 0.2 mM Na2SO4, 0.3 mM MES, pH 6.0
通讯作者:厦门大学郑海雷、陈娟
英文摘要
It is well known that nitric oxide (NO) enhances salt tolerance of glycophytes. However, the effect of NO on modulating ionic balance in halophytes is not very clear. This study focuses on the role of NO in mediating K+/Na+ balance in a mangrove species, Kandelia obovata Sheue, Liu and Yong.
We first analyzed the effects of sodium nitroprusside (SNP), an NO donor, on ion content and ion flux in the roots of K. obovata under high salinity. The results showed that 100 μM SNP significantly increased K+ content and Na+ efflux, but decreased Na+ content and K+ efflux. These effects of NO were reversed by specific NO synthesis inhibitor and scavenger, which confirmed the role of NO in retaining K+ and reducing Na+ in K. obovata roots.
Using western-blot analysis, we found that NO increased the protein expression of plasma membrane (PM) H+-ATPase and vacuolar Na+/H+ antiporter, which were crucial proteins for ionic balance. To further clarify the molecular mechanism of NO-modulated K+/Na+ balance, partial cDNA fragments of inward-rectifying K+ channel, PM Na+/H+ antiporter, PM H+-ATPase, vacuolar Na+/H+ antiporter and vacuolar H+-ATPase subunit c were isolated. Results of quantitative real-time PCR showed that NO increased the relative expression levels of these genes, while this increase was blocked by NO synthesis inhibitors and scavenger.
Above results indicate that NO greatly contribute to K+/Na+ balance in high salinity-treated K. obovata roots, by activating AKT1-type K+ channel and Na+/H+ antiporter, which are the critical components in K+/Na+ transport system.
Effects of NaCl and SNP on K+ and Na+ fluxes in K. obovata roots. After 15 days of exposure to NaCl (400 mM), SNP (100 mM) and NaCl (400 mM)+SNP (100 mM), the net K+ (A) and Na+ (C) fluxes from the mature root zone (20 mm from the tip) of K. obovata seedlings. The positive value in the figures represents the net influx and negative value represents the net efflux. Each point represents the mean value of four individual roots and bars represent the SE of the mean. The mean fluxes of K+ (B) and Na+ (D) within the measuring periods are shown. Columns labeled with different letters indicates significantly different at P,0.05.
2012年8月16日,中国农科院兰州畜牧与兽药研究所王晓力副研究员同兰州大学张金林副教授利用NMT在Plant Science上发表了标题为The coordinated regulation of Na+ and K+ in Hordeum brevisubulatum responding to time of salt stress的研究成果。
期刊:Plant Science
主题:响应盐胁迫时间的大麦Na+和K+的调控
标题:The coordinated regulation of Na+and K+ in Hordeum brevisubulatum responding to time of salt stress
影响因子:3.362
检测指标:Na+,K+流速
检测部位:野大麦根尖部位
Na+,K+流实验处理方法:
四叶期大麦,0/100mM NaCl处理7天,100mM NaCl处理60天
Na+,K+流实验测试液成份:
0.1 mMKCl, 0.1 mM CaC12, 0.1 mM MgC12, 0.5 mM NaCl, 0.2 mM Na2SO4,0.3 mM MES, pH 6.0
通讯作者:中国农科院兰州畜牧与兽药研究所王晓力、兰州大学张金林
英文摘要
Hordeum brevisubulatum, called as wild barley, is a useful monocotyledonous halophyte for soil improvement in northern China. Although previously studied, its main salt tolerance mechanism remained controversial.
The current work showed that shoot Na+ concentration was increased rapidly with stress time and significantly higher than in wheat during 0–168 h of 100 mM NaCl treatment. Similar results were also found under 25 and 50 mM NaCl treatments. Even K+ was increased from 0.01 to 50 mM in the cultural solution, no significant effect was found on tissue Na+ concentrations. Interestingly, shoot growth was improved, and stronger root activity was maintained in H.
brevisubulatum compared with wheat after 7 days treatment of 100 mM NaCl. To investigate the long-term stress impact on tissue Na+, 100 mM NaCl was prolonged to 60 days. The maximum values of Na+ concentrations were observed at 7th in shoot and 14th day in roots, respectively, and then decreased gradually. Micro-electrode ion flux estimation was used and it was found that increasing Na+ efflux while maintaining K+ influx were the major strategies to reduce the Na+ concentration during long-term salt stress. Moreover, leaf Na+ secretions showed little contribution to the tissue Na+ decrease.
Thereby, the physiological mechanism for H. brevisubulatum to survive from long-term salt stress was proposed that rapid Na+ accumulation occurred in the shoot to respond the initial salt shock, then Na+ efflux was triggered and K+ influx was activated to maintain a stable K+/Na+ ratio in tissues.
Fig. 4. Net Na+ flux of H. brevisubulatum test by MIFE between 50 and 390 s in mea-suring solution after 0 and 100 mM NaCl treatment (increased stepwise with 25 mM per 12 h) in modified Hoagland solution for 7 d and 100 mM NaCl for 60 d. Roots (with shoots retained) were incubated in the measuring solution to equilibrate for 15 min in advance. Steady-state ion fluxes were then recorded until the values variation amplitude is relatively stable. Ten plants for H. brevisubulatum were pooled in each replicate (n = 6). Values are means ± SD and bars indicate SD.
2017年8月14日,中央民族大学夏建新、北京林业大学陈少良利用NMT在Frontiers in Plant Science上发表了标题为Salt-Sensitive Signaling Networks in the Mediation of K+/Na+ Homeostasis Gene Expression in Glycyrrhiza uralensis Roots的文章。
期刊:Frontiers in Plant Science
主题:盐敏感信号网络在甘草根中Na+/K+稳态基因表达的调控
标题:Salt-Sensitive Signaling Networks in the Mediation of K+/Na+ Homeostasis Gene Expression in Glycyrrhiza uralensis Roots
两周的甘草幼苗,0/100mM NaCl处理24小时后,促进剂(Ca2+, H2O2, SNP, and ATP)或者抑制剂(阿米洛利,原钒酸钠,TEA,LaCl3,DMTU,cPTIO和PPADs)处理30min
Na+,K+,H+流实验测试液成份:
0.1 mM NaCl, 0.1 mM MgCl2, 0.1 mM CaCl2, and 0.5 mM KCl
通讯作者:中央民族大学夏建新、北京林业大学陈少良
英文摘要
We investigated the effects of salt-sensitive signaling molecules on ionic fluxes and gene expression related to K+/Na+ homeostasis in a perennial herb, Glycyrrhiza uralensis, during short-term NaCl stress (100 mM, 24 h). Salt treatment caused more pronounced Na+ accumulation in root cells than in leaf cells. Na+ ions were mostly compartmentalized in vacuoles. Roots exposed to NaCl showed increased levels of extracellular ATP (eATP), cytosolic Ca2+, H2O2, and NO.
Steady-state flux recordings revealed that these salt-sensitive signaling molecules enhanced NaCl-responsive Na+ efflux, due to the activated Na+/H+ antiport system in the plasma membrane (PM). Moreover, salt-elicited K+ efflux, which was mediated by depolarization-activated cation channels, was reduced with the addition of Ca2+, H2O2, NO, and eATP. The salt-adaptive effects of these molecules (Na+ extrusion and K+ maintenance) were reduced by pharmacological agents, including LaCl3 (a PM Ca2+ channel inhibitor), DMTU (a reactive oxygen species scavenger), cPTIO (an NO scavenger), or PPADS (an antagonist of animal PM purine P2 receptors).
RT-qPCR data showed that the activation of the PM Na+/H+ antiport system in salinized roots most likely resulted from the upregulation of two genes, GuSOS1 and GuAHA, which encoded the PM Na+/H+ antiporter, salt overly sensitive 1 (SOS1), and H+-ATPase, respectively. Clear interactions occurred between these salt-sensitive agonists to accelerate transcription of salt-responsive signaling pathway genes in G. uralensis roots.
For example, Ca2+, H2O2, NO, and eATP promoted transcription of GuSOS3 (salt overly sensitive 3) and/or GuCIPK (CBL-interacting protein kinase) to activate the predominant Ca2+-SOS signaling pathway in salinized liquorice roots. eATP, a novel player in the salt response of G. uralensis, increased the transcription of GuSOS3, GuCIPK, GuRbohD (respiratory burst oxidase homolog protein D), GuNIR (nitrate reductase), GuMAPK3, and GuMAPK6 (the mitogen-activated protein kinases 3 and 6). Moreover, GuMAPK3 and GuMAPK6 expression levels were enhanced by H2O2 in NaCl-stressed G. uralensis roots.
Our results indicated that eATP triggered downstream components and interacted with Ca2+, H2O2, and NO signaling to maintain K+/Na+ homeostasis. We propose that a multiple signaling network regulated K+/Na+ homeostasis in NaCl-stressed G. uralensis roots.
(A) Na+ and (B) K+ were measured along the root axis at the apical zones (200–2700 µm from the root tip) in no-salt (left panels) and salt-stressed (center panels) conditions. Each point represents the mean of five to six individual plants. ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, compared to controls. (Right panels) Means of Na+ and K+ fluxes at all measurement points, in no-salt (–NaCl) and salt-stressed (+NaCl) plants. Bars (±SD) represent the means of five to six individual plants; different letters (a, b, c, and d) indicate significant differences (P < 0.05) between treatments.
The impact of freshwater (FW) salinization on osmoregulation as well as tracheal gill morphology and function was examined in nymphs of the mayfly Hexagenia rigida following exposure to salt contaminated water (SCW, 7.25 g/l NaCl) for a 7-day period.
Ionoregulatory homeostasis was perturbed in SCW exposed H. rigida nymphs as indicated by increased hemolymph Na+, K+ and Cl− levels as well as hemolymph pH and water content. Despite this, SCW did not alter gill Na+-K+-ATPase (NKA) or V-type H+-ATPase (VA) activity. In addition, NKA and VA immunolocalization in gill ionocytes did not show alterations in enzyme location or changes in ionocyte abundance.
The latter observation was confirmed using scanning electron microscopy (SEM) to examine exposed tracheal gill ionocyte numbers. Ionocyte surface morphometrics also revealed that SCW did not change individual ionocyte surface area or ionocyte fractional surface area. Nevertheless, analysis of Na+ movement across the tracheal gill of mayfly nymphs using scanning ion-selective electrode technique indicated that FW nymphs acquired Na+ from surrounding water, while tracheal gills of SCW nymphs had the capacity to secrete Na+.
Because Na+ secretion across the gill of SCW-exposed animals occurred in the absence of any change in (1) NKA and VA activity or (2) ionocyte numbers/surface exposure, it was reasoned that Na+ movement across the gill of SCW animals may be occurring, at least in part, through the paracellular pathway. The ultrastructure of tracheal gill septate junctions (SJs) supported this idea as they exhibited morphological alterations indicative of a leakier pathway. Data provide a first look at alterations in osmoregulatory mechanisms that allow H. rigida nymphs to tolerate sub-lethal salinization of their surroundings.
中文摘要(谷歌机翻)
在暴露于盐污染的水(SCW,7.25g / l NaCl)7天后,在may fly(Hexflynia rigida)的若虫中检查淡水(FW)盐化对渗透调节以及气管鳃形态和功能的影响。
2012年8月9日,河北师范大学黄占景、肖艳红利用NMT在Physiologia Plantarum上发表了标题为A novel wheat α-amylase inhibitor gene, TaHPS, significantly improves the salt and drought tolerance of transgenic Arabidopsis的文章。
期刊:Physiologia Plantarum
主题:一种新型小麦α-淀粉酶抑制剂基因TaHPS显着提高了转基因拟南芥的耐盐性和耐旱性
标题:A novel wheat α-amylase inhibitor gene, TaHPS, significantly improves the salt and drought tolerance of transgenic Arabidopsis
影响因子:3.656
检测指标:Na+、K+、Ca2+流速
检测部位:根、保卫细胞
Na+、K+、Ca2+流实验处理方法:
5天的小麦幼苗,0或200mM NaCl处理1天
Na+、K+、Ca2+流实验测试液成份:文献无
推荐测试液成份:
Na+(根):0.5mM NaCl,pH 6.0
Ca+、K+(保卫细胞):0.1mM CaCl2,0.1mM KCl,pH 6.0
通讯作者:河北师范大学黄占景、肖艳红
英文摘要
On the basis of microarray analyses of the salt‐tolerant wheat mutant RH8706‐49, a previously unreported salt‐induced gene, designated as TaHPS [Triticum aestivum hypothetical (HPS)‐like protein], was cloned.
Real‐time quantitative polymerase chain reaction analyses showed that expression of the gene was induced by abscisic acid, salt and drought. The encoded protein was found to be localized mainly in the plasma membranes. Transgenic Arabidopsis plants overexpressing TaHPS were more tolerant to salt and drought stresses than non‐transgenic wild‐type (WT) plants. Under salt stress, the root cells of the transgenic plants secreted more Na+ and guard cells took up more Ca2+ ions. Compared with wild‐type plants, TaHPS‐expressing transgenic plants showed significantly lower amylase activity and glucose and malic acid levels.
Our results showed that the expression of TaHPS inhibited amylase activity, which subsequently led to a closure of stomatal apertures and thus improved plant tolerance to salt and drought.
Phenotypes of plants treated with NaCl and PEG for three weeks. (A) Treated with 0 mM NaCl for 3 weeks.Non-destructive determination of centrifugal flow and fluxes.(A) Flow and fluxes of Na+ in root cells.
In this study, in order to investigate the role of Ca2+ in GABA signal transduction involved in phenolics accumulation in barley seedlings under NaCl stress, the seedlings were treated with exogenous GABA and its synthesis inhibitor, 3-mercaplopropionic acid (3-MP), as well as Ca2+ channel blockers La3+, Ca2+ chelator EGTA, and Ca2+ release channel inhibitor 2-aminoethoxydiphenyl borate (2-APB).
The results showed that GABA significantly enhanced phenolics, calcium and calmodulin content. It also induced Ca2+ influx in barley root tips cells, and altered the distribution of Ca2+, making calcium precipitates more uniform and intensive. While, 3-MP treatment led to opposite changes, which suggested that GABA was essential for calcium content increase. In addition, accumulation of phenolics was inhibited by LaCl3, EGTA and 2-APB treatments, and this inhibition could be alleviated partly by exogenous GABA.
Taken together, Ca2+ was involved in GABA signal transduction for phenolics accumulation in barley seedlings under NaCl stress.
标题:The involvement of wheat (Triticum aestivum L.) U-box E3 ubiquitin ligase TaPUB1 in salt stress tolerance
影响因子:3.129
检测指标:Na+、K+、H+流速
检测部位:根部分生区
Na+、K+、H+流实验处理方法:
7日龄小麦,200mM NaCl瞬时胁迫处理/200uM NaC处理7天
Na+、K+、H+流实验测试液成份:文献无
推荐测试液成份:
Na+/H+:0.5mM NaCl ,0.3mM MES,pH6.0
K+/H+:0.1mM KCl ,0.3mM MES,pH6.0
通讯作者:山东农业大学王玮、枣庄学院王文强
英文摘要
U‐box E3 ubiquitin ligases play important roles in the ubiquitin/26S proteasome machinery and in abiotic stress responses. TaPUB1‐overexpressing wheat (Triticum aestivum L.) were generated to evaluate its function in salt tolerance. These plants were more salt stress tolerance during seedling and flowering stages, whereas the TaPUB1‐RNAi‐mediated knock‐down transgenic wheat showed more salt stress sensitivity than the wild type (WT).
TaPUB1 overexpression up‐regulated the expression of genes related to ion channels and increased the net root Na+ efflux, but decreased the net K+ efflux and H+ influx, thereby maintaining a low cytosolic Na+/K+ ratio, compared with the WT. However, RNAi‐mediated knock‐down plants showed the opposite response to salt stress. TaPUB1 could induce the expression of some genes that improved the antioxidant capacity of plants under salt stress. TaPUB1 also interacted with TaMP (Triticum aestivum.α‐mannosidase protein), a regulator playing an important role in salt response in yeast and in plants.
Thus, low cytosolic Na+/K+ ratios and better antioxidant enzyme activities could be maintained in wheat with overexpression of TaPUB1 under salt stress. Therefore, we conclude that the U‐box E3 ubiquitin ligase TaPUB1 positively regulates salt stress tolerance in wheat.
与WT相比,TaPUB1过表达上调与离子通道相关的基因的表达并增加净根Na +流出,但降低净K +流出和H +流入,从而维持低细胞溶质Na + / K +比率。然而,RNAi介导的敲低植物显示出对盐胁迫的相反反应。TaPUB1可诱导某些基因的表达,从而提高盐胁迫下植物的抗氧化能力。TaPUB1还与TaMP(Triticumaestivum.α-甘露糖苷酶蛋白)相互作用,TaMPUB是一种在酵母和植物中的盐响应中起重要作用的调节剂。
因此,在盐胁迫下过表达TaPUB1的小麦中可以维持较低的细胞溶质Na + / K +比率和较好的抗氧化酶活性。因此,我们得出结论,U-box E3泛素连接酶TaPUB1正调节小麦的盐胁迫耐受性。
Figure 4. Accumulation of Na+ and K+ in transgenic and WT plants under normal and salt stress conditions (E) The Na+/K+ ratio in the roots of transgenic and WT plants exposed to 0 mM and 200 mM NaCl. (F and G) Quantification of Na+ and K+ content in leaves of transgenic and WT plants without and with 200 mM NaCl treatment. (H) The Na+/K+ ratio in the leaves of transgenic and WT plants exposed to 0 mM and 200 mM NaCl. The data were presented as the mean ±SD of three independent experiments. Asterisks above each column indicate statistical differences to the WT plants (*P<0.05; **P<0.01).
Aquaporins (AQPs) are channel proteins that facilitate water transport across cell membranes and play important roles in many biological processes. However, most AQP functions are still poorly understood in the plant kingdom. Here, MsPIP2;2 was isolated and identified from alfalfa (Medicago sativa). MsPIP2;2 was localized to the plasma membrane, and its expression was induced by salt and abscisic acid (ABA) treatment. Overexpression of MsPIP2;2 in Arabidopsis increased the seed germination rate, seedling root length, survival rate, proline content and antioxidant defence activity and decreased cell membrane damage and reactive oxygen species (ROS) accumulation compared to those in WT under salt stress.
The salt tolerance of MsPIP2;2 was affected by Ca2+ and pH in transgenic Arabidopsis plants. MsPIP2;2-overexpressing plants maintained a better K+/Na+ ratio and higher Ca2+ content under salt stress. The higher K+/Na+ maintenance in transgenic plants was mainly achieved by increasing Na+ efflux and K+ retention in roots via regulating the expression of the related ion channel genes. Stress-responsive genes, including P5CS1, RD29A, DREB2 and KIN2, were upregulated in transgenic plants under salt stress.
These results suggest that MsPIP2;2 confers salt tolerance by regulating antioxidant defence system-mediated ROS scavenging, K/Na ion homeostasis and stress-responsive gene expression in plants.
Fig. 9. The net flux of Na+ and K+ at the root tip elongation zones of 7-day-old Arabidopsis seedlings. (A) The net Na+ flux under normal conditions (0 mM NaCl). (B) The net Na+ flux after 150 mM NaCl stress. (C) The mean Na+ flux. (D) The net K+ flux under normal conditions (0 mM NaCl). (E) The net K+ flux after 150 mM NaCl stress. (F) The mean K+ flux. Bars represent the mean ± SE (n = 3). Asterisks and double asterisks above the bars indicate significant differences between the transgenic lines and the WT under the same growth conditions: *, P < 0.05; **, P < 0.01.
标题:Tissue-specific respiratory burst oxidase homologue -dependent H2O2 signaling to the plasma membrane H+-ATPase confers potassium uptake and salinity tolerance in Cucurbitaceae
影响因子:5.360
检测指标: K+流速
检测部位:距离根尖1mm
K+流实验处理方法:
5日龄黄瓜幼苗,75mM NaCl处理24小时
K+流实验测试液成分:
0.5mM KCl,0.1mM CaCl2,pH 5.7
作者:华中农业大学别之龙、黄远
英文摘要
Potassium (K+) is a critical determinant ofsalinity tolerance, and H2O2 has been recognised as an important signalingmolecule that mediates many physiological responses. However, the details onhow H2O2 signaling regulates potassium uptake in the root under salt stressremain elusive. In this study, the salt sensitive cucumber and salt tolerantpumpkin which belong to the same family cucurbitaceae were used to answer theabove question.
Weshow that higher salt tolerance in pumpkin was related to its superior abilityfor K+ uptake and higher H2O2 accumulation in the root apex. Transcriptomeanalysis showed that salinity induced 5886 (3005 up and 2811 down) and 4679(3965 up and 714 down) differentially expressed genes (DEGs) in cucumber andpumpkin, respectively. DEGs encoding NADPH oxidase (RBOHD), 14-3-3 protein(GRF12), plasma membrane H+- ATPase (AHA1) and potassium transporter (HAK5)showed higher expression in pumpkin than cucumber under salinity stress.Treatment with a NADPH oxidase inhibitor diphenylene iodonium resulted in alower RBOHD, GRF12, AHA1 and HAK5 expression, reduced plasma membrane H+-ATPase activity, and smaller K+ uptake, resulting in a loss of salinitytolerance trait in pumpkin. The opposite results were obtained when the plantswere pre-treated with exogenous H2O2. Knocking out of RBOHD in pumpkin byCRISPR-Cas9 editing of coding sequences resulted in lower root apex H2O2 and K+content and GRF12, AHA1 and HAK5 expression, ultimately resulting in asalt-sensitive phenotype. However, ectopic expression of pumpkin RBOHD inArabidopsis led to the opposite effect.
Taken together, this study shows that RBOHD-dependent H2O2 signaling in the root apex is important for the pumpkin salttolerance and suggests a novel mechanism that confers this trait, namelyRBOHD-mediated transcriptional and post-translational activation of plasmamembrane H+-ATPase operating upstream of HAK5 K+ uptake transporters.
Figure 7. Relative expression of GRF (14-3-3 protein), AHA (plasma membrane H+-ATPase) and HAK5 (high affinity K+ transporter) in the root apex of cucumber (A, C, E) and pumpkin (B, D, F) exposed to 75 mM NaCl for 24 h. (G) to (J): plasma membrane H+-ATPase activity and net K+ flux measured after 24 h of exposure to 75 mM NaCl stress from the root apex pre-treated for 1 h in solutions containing specific chemicals (DPI, an NADPH oxidase inhibitor, H2O2) in cucumber (G, I) and pumpkin (H, J). Values are the mean ± SE (n=4). Different letters indicate significant difference (P < 0.05) according to Duncan's multiple range tests. The gene ID for cucumber GRF, AHA and HAK5 is Csa3G890040 (GRF8), Csa1G045600 (AHA11) and Csa3G835810 (HAK5), and it is CmoCh01G016540 (GRF12), CmoCh11G003690 (AHA1) and CmoCh08G004000 (HAK5) for pumpkin.
标题:Phosphatase GhDsPTP3a interacts with annexin protein GhANN8b to reversely regulate salt tolerance in cotton (Gossypium spp.)
影响因子:7.299
检测指标:Ca2+、Na+、K+流速
Ca2+流实验方法:
7d拟南芥,100 mM NaCl瞬时盐胁迫处理,检测距根尖1000微米的点
Ca2+流实验测试液成份: 0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, 0.1 % sucrose, pH 6.0
K+、Na+流实验方法:
· 5d拟南芥,0、100 mM NaCl处理24h,检测距根尖200微米的点 · 6d拟南芥,50 uM LaCl3+100 mM NaCl处理24h,检测距根尖200微米的点
K+、Na+流实验测试液成份: 0.5 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.1 mM NaCl, 0.3 mM MES, pH 6.0
作者:中国农业大学李芳军、穆春、得州农工大学单立波
英文摘要
Salinity is among the major factorslimiting crop production worldwide. Despite having moderate salt‐tolerance,cotton (Gossypium spp.) suffers severe yield losses to salinity stresses,largely due to being grown on saline‐alkali and drylands.
To identify genetic determinants conferringsalinity tolerance in cotton, we deployed a functional genomic screen using acotton cDNA library in a virus‐induced gene silencing (VIGS) vector. We have revealed thatsilencing of GhDsPTP3a, which encodes a protein phosphatase, increases cottontolerance to salt stress.
Yeast two‐hybrid screensindicated that GhDsPTP3a interacts with GhANN8b, an annexin protein, whichplays a positive role in regulating cotton response to salinity stress. Saltstress induces GhANN8b phosphorylation, which is subsequently dephosphorylated byGhDsPTP3a. Ectopic expression of GhDsPTP3a and GhANN8b oppositely regulatesplant salt tolerance and calcium influx. In addition, we have revealed thatsilencing of GhDsPTP3a or GhANN8b exerts opposing roles in regulating GhSOS1transcript levels, and ectopic expression of GhANN8b elevates Na+ efflux inArabidopsis under salinity stress.
Our study demonstrates that a cottonphosphatase GhDsPTP3a and an annexin protein GhANN8b interact and reverselymodulate Ca2+ and Na+ fluxes in cotton salinity responses.
(b) Ectopic-expression of GhDsPTP3a or GhANN8b alters extracellular Na+ efflux upon salt stress in live roots via NMT assay. (c) LaCl3 blocks GhANN8b-induced Na+ efflux upon salt stress in live roots via NMT assay.
标题:Root vacuolar Na+ sequestration but not exclusion from uptake correlates with barley salt tolerance
影响因子:5.775
检测指标:Na+、H+
通讯作者:塔斯马尼亚大学Sergey Shabala,华中农业大学吴洪洪
英文摘要
Soil salinity is a major constraint for the global agricultural production. For many decades, Na+ exclusion from uptake has been the key trait targeted in breeding programs; yet, no major breakthrough in creating salt tolerant germplasm was achieved.
In this work, we have combined the MIFE technique for non‐invasive ion flux measurements with confocal fluorescence dye imaging technique to screen 45 accessions of barley to reveal the relative contribution of Na+ exclusion from the cytosol to the apoplast and its vacuolar sequestration in the root apex, for the overall salinity stress tolerance.
We show that Na+/H+ antiporter‐mediated Na+ extrusion from the root plays a minor role in the overall salt tolerance in barley. At the same time, a strong and positive correlation was found between root vacuolar Na+ sequestration ability and the overall salt tolerance. The inability of salt sensitive genotypes to sequester Na+ in root vacuoles was in a contrast to a significantly higher expression levels of both HvNHX1 tonoplast Na+/H+ antiporters and HvVP1 H+‐pumps compared with tolerant genotypes. This data is interpreted as a failure of sensitive varieties to prevent Na+ back‐leak into the cytosol and existence of a futile Na+ cycle at the tonoplast.
Taken together, our results demonstrated that root vacuolar Na+ sequestration but not exclusion from uptake played the main role in barley salinity tolerance and suggested that the focus of the breeding programs should be shifted from targeting genes mediating Na+ exclusion from uptake by roots to more efficient root vacuolar Na+ sequestration.
Co-expression of SpSOS1 and SpAHA1 in transgenic Arabidopsis plants improves salinity tolerance. BMC Plant Biology, 2019, 19(1):74.
Overexpression of the PtSOS2 gene improves tolerance to salt stress in transgenic poplar plants. Plant Biotechnology Journal, 2015, 13(7): 962-73.
Co-expression of the Arabidopsis SOS genes enhances salt tolerance in transgenic tall fescue (Festuca arundinacea Schreb.). Protoplasma, 2014, 251(1):219-31.
SOS1 gene overexpression increased salt tolerance in transgenic tobacco by maintaining a higher K+/Na+ ratio. Journal of plant physiology, 2012, 169(3): 255-261.
Nax loci affect SOS1-like Na+/H+ exchanger expression and activity in wheat. Journal of Experimental Botany, 2016, 67(3):835-44.
Haem oxygenase modifies salinity tolerance in Arabidopsis by controlling K+ retention via regulation of the plasma membrane H+-ATPase and by altering SOS1 transcript levels in roots. Journal of Experimental Botany, 2013, 64(2): 471-481.
Na+-H+ antiporter activity of the SOS1 gene, lifetime imaging analysis and electrophysiological studies on Arabidopsis seedlings. Physiologia Plantarum, 2009,137(2):155-65.
作者: xuyuenmt 更新时间:2022-07-05 07:49
JXB:华中农大别之龙|离子流揭示中国南瓜与印度南瓜的耐盐策略
2018年7月,华中农大园艺林学学院别之龙教授团队关于不同遗传背景南瓜材料耐盐性策略差异的研究成果在Journal of Experimental Botany上发表题为An early ABA-induced stomatal closure, Na+ sequestration in leaf vein and K+ retention in mesophyll confer salt tissue tolerance in Cucurbita species的研究成果。牛蒙亮、陈晨、谢俊俊为本文共同第一作者,别之龙、黄远为并列通讯作者。
葫芦科中南瓜具有较强的耐盐性,在瓜类嫁接中广泛用作黄瓜、西瓜等盐敏感材料的砧木,具有较强的限制Na+等盐害离子向地上部运转的能力,其中生产中的南瓜砧木多为中印南瓜杂合体(Cucurbita maxima × Cucurbita moschata)材料。
前期研究发现,中国南瓜(Cucurbita moschata)和印度南瓜(Cucurbita maxima)二者具有显著差异的Na+积累模式与耐盐能力(A shoot based Na+ tolerance mechanism observed in pumpkin—An important consideration for screening salt tolerant rootstocks. 2017, Scientia Horticulturae, 218:38-47.),某些特殊的南瓜材料在维持叶片中高Na+含量的同时依然具有极强的耐盐能力,这引起了研究者对这些材料耐盐策略的兴趣,其Na+转运过程具有哪些不同寻常之处?
An early ABA-induced stomatal closure, Na+ sequestration in leaf vein and K+ retention in mesophyll confer salt tissue tolerance in Cucurbita species. Journal of Experimental Botany. 2018, 69(20):4945-4960.
Root respiratory burst oxidase homologue-dependent H2O2 production confers salt tolerance on a grafted cucumber by controlling Na+ exclusion and stomatal closure. Journal of Experimental Botany. 2018, 69(14):3465-3476.(JXB:华中农大别之龙NMT揭示嫁接黄瓜根源H2O2促耐盐机制)
Scanning ion-selective electrode technique and X-ray microanalysis provide direct evidence of contrasting Na+ transport ability from root to shoot in salt-sensitive cucumber and salt-tolerant pumpkin under NaCl stress. Physiologia Plantarum. 2014, 152(4):738-48.
致 谢
感谢本文第一作者牛蒙亮博士供稿。 欢迎大家联系我们踊跃投稿,010-8262 4800。
作者: xuyuenmt 更新时间:2022-07-05 07:52
SCI REP-UK :山东农大丨NaCl胁迫下磁处理可调控杨树N代谢
期刊:Scientific Report
主题:NaCl胁迫下磁处理可调控杨树N代谢
标题:The effects of magnetic treatment on nitrogen absorption and distribution in seedlings of Populus × euramericana ‘Neva’ under NaCl stress
NH4+、NO3-流实验测试液成份: NH4+: 0.1 mM NH4NO3, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5 NO3-: 0.1 mM NH4NO3, 1.0 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
作者:山东农业大学林学院马风云、刘秀梅
英文摘要
A potted experiment with Populus × euramericana ‘Neva’ was carried out to assess whether there are positive effects of magnetic treatment of saline water (MTSW) on nitrogen metabolism under controlled conditions in a greenhouse. Growth properties, nitrogen contents, enzyme activities and metabolite concentrations were determined based on field experiments and laboratory analysis after a 30-day treatment.
The results were as follows: (1) Biomass accumulation, root morphological properties and total nitrogen content were improved by MTSW. (2) Magnetization led to a greater increase in nitrate-nitrogen (NO3−-N) content in roots than in leaves, accompanied by greater NO3− efflux and activated nitrate reductase. (3) MTSW led to a higher ammonium-nitrogen (NH4+-N) content and greater uptake of net NH4+ in the leaves than that in the roots. (4) Magnetization stimulated glutamine synthase, glutamate dehydrogenase and glutamate synthase activities, whereas the concentrations of glutathione and oxidized glutathione were increased in leaves but decreased in roots, and the total glutathione content was increased.
Overall, these results indicated some beneficial impacts of MTSW on nitrogen translocation under field conditions, especially for equilibrating the distribution of NO3−-N and NH4+-N. Moreover, these findings confirmed the potential of using low-quality water for agriculture.
标题:Phosphatidylserine Synthase from Salicornia europaea Is Involved in Plant Salt Tolerance by Regulating Plasma Membrane Stability
作者:中科院植物所李银心、吕素莲、台方
检测离子/分子指标
K+
检测样品
盐角草根细胞
中文摘要(谷歌机翻)
盐诱导的脂类改变在许多植物物种中已有报道,然而,脂类生物合成和代谢如何调控,脂类在植物耐盐性中如何发挥作用的研究却少得多。在本研究中,盐角草细胞质膜(PM)中磷脂酰丝氨酸(PS)含量明显高于拟南芥。随后从盐角草中分离到一个编码磷脂酰丝氨酸合成酶(PSS)的基因,命名为SePSS。多重比对和系统发育分析表明,SePSS属于碱基交换型PSS,位于内质网。在400或800 mM NaCl胁迫下,SePSS在盐角草悬浮细胞中的失活导致PS含量降低,细胞存活率降低,PM去极化和K+外排增加。相比之下,SePSS的上调导致拟南芥PS和磷脂酰乙醇胺(PE)水平升高,耐盐性增强,同时转基因株系中活性氧积累比WT低,膜损伤较少,PM去极化较少,K+/Na+较高。这些结果表明,PS水平与植物耐盐性呈正相关,SePSS通过调节PS水平参与植物耐盐性,进而调节PM电位和通透性,维持离子稳态。本研究的工作内容为改善植物在多重胁迫下的生长提供了一个潜在的策略。
离子/分子流实验处理
0、400、800 mM NaCl处理2 h
离子/分子流实验结果
盐胁迫下,植物的PM常常会发生去极化,导致K+从细胞中渗出。为了研究SePSS在盐胁迫下调节膜电位的可能作用,分别用0、400和800 mM NaCl处理空载体(empty vector,EV)细胞和SePSS-RNAi细胞。采用非损伤微测技术(NMT)检测K+净流速,与无盐处理相比,400和800 mM NaCl处理使EV细胞K+内流减少,800 mM NaCl处理使SePSS-RNAi细胞K+由内流转为外排(图1)。这些结果表明,敲除SePSS可能会加剧NaCl诱导的PM去极化,从而导致K+从细胞中渗漏。
标题:Changes in Expression Level of OsHKT1;5 Alters Activity of Membrane Transporters Involved in K+and Ca2+ Acquisition and Homeostasis in Salinized Rice Roots
当向WT植株根施加80 mM NaCl(模拟木质部汁液Na+浓度的增加)时,可测到强烈而持续的净Na+吸收(图1A, C)。从功能上讲,这种吸收与根木质部对Na+的重吸收是一致的(无论是通过HKT1;5还是通过一些其他运输系统)。然而,在NIL(SKC1)中,没有这种吸收。相反,敲低(Knockdown, KD)株系表现出木质部薄壁细胞对Na+的净吸收甚至略高于WT(图1A,C)。这些结果与本文全株Na+含量数据结果一致。
② 100 mM NaCl处理24 h,然后转移到无钠的1/4 Hoagland营养液中,在有无H2的情况下处理60 min
③ HRW处理30 min后,100 mM NaCl实时处理
④ HRW+100 mM NaCl同时实时处理
⑤ HRW处理30 min后,10 mM H2O2实时处理
⑥ HRW+10 mM H2O2同时实时处理
离子/分子流实验结果
植物体内Na+含量降低可能与Na+吸收降低或Na+外排速率增加有关。这些可能性使用非损伤微测技术(NMT)得到了验证。盐处理诱导根表皮产生大量的Na+瞬时净流入(图1A);在经过HRW预处理的根中,这种内流大约减少50%。研究随后试图评估一种可能性,即上述净Na+吸收的差异是由于Na+外排速率较高所致。用100 mM NaCl溶液处理根系24 h后,将根系转移到不含H2的无钠测试液中。HRW预处理后的根系中Na+净外排速率提高了2倍(图1B),与上述结果一致。
图1. HRW对5日龄大麦幼苗成熟区的Na+净流速影响。(A)加入100 mM NaCl,在不同时间点(处理后10、30、60和120 min)测量Na+净流速。(B)从100 mM NaCl溶液(24 h处理)转移到无钠的1/4 Hoagland's溶液中,在有无H2情况下处理60 min后测量的稳定Na+外排速率。正值表示吸收,负值表示外排。
图3. HRW对实时10 mM H2O2处理下5日龄大麦幼苗成熟根区测定的实时K+(A)和Ca2+(B)流速的影响。“Pre-HRW”是指在加入10 mM H2O2和NaCl之前,将幼苗转入HRW溶液中30 min。在“HRW”处理中,HRW与H2O2一起添加到溶液中。
其他实验结果
在没有盐胁迫的情况下,HRW可以增加根长,但不会显著影响鲜重、叶片叶绿素含量或叶绿素荧光Fv/Fm。轻度(100 mM NaCl)盐胁迫会显著抑制根系生长(例如减少长度);施用HRW可以大大减轻这种抑制作用。与对照相比,更严重的胁迫(200 mM NaCl)导致植物的根更短,鲜重更低,叶绿素含量或Fv/Fm更低。施用HRW可以强烈逆转盐度的这些不利影响。
FDA-PI双色荧光染色结果显示,在对照或HRW条件下,死细胞不超过10%,在100 mM NaCl处理下,该比例增加。在施用HRW下,这种损伤明显缓解。NaCl处理诱导大麦苗根部H2O2的大量积累,与对照和HRW处理相比,H2O2的积累增加了3倍以上。这种增加被HRW有效抑制。
标题:Leaf mesophyll K+ and Cl- fluxes and reactive oxygen species production predict rice salt tolerance at reproductive stage in greenhouse and field conditions
为了进一步了解SLAH3 S601位点的生理作用,研究采用非损伤微测技术(NMT)对硝酸盐流速进行了分析。为检验Cl-是否干扰NMT系统中NO3-的检测,在无幼苗的情况下分别检测测试液1(1 mM KNO3, 0.1mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 6.0)和测试液2(1 mM KNO3, 1.1 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 6.0)中NO3-的浓度和净流速。Cl-的存在不干扰NO3-的检测(图2)。其次,本研究检测了根尖附近成熟区的NO3-净流速(图1A,图3A)。对Col-0、slah3-3、slah3-4幼苗和所有互补株系在1/2 MS培养基上生长8 d后转入高NH4+/低pH条件(1 mM NO3-, 10 mM NH4+, pH 4.5)或非高NH4+/低pH条件(1 mM NO3-, 1 mM NH4+, pH 5.7)2 h后进行检测。在6 min内检测到来自植物根系的NO3-流速(图1B,图3B)。在高NH4+/低pH胁迫下,Col-0的NO3-外排速率平均值约为93 pmol cm-2s-1,slah3突变体的NO3-外排速率平均值约为0 pmol cm-2s-1。slah3-4背景下的互补株系SLAH3和SLAH3 S601A显示出与Col-0植株类似的硝酸盐外排。相比之下,slah3-4背景下互补株系SLAH3 S601D的硝酸盐外排与slah3突变体相似(图1B)。此外,在非高NH4+/低pH胁迫下,所有植物的硝酸盐外排相似,NO3-外排速率的平均值均在0 pmol cm-2s-1左右(图3)。这些结果表示SLAH3的S601在高NH4+/低pH胁迫下对硝酸盐外排起重要的调节作用。
150 mM NaCl短期(ST, 24 h)处理后,胡杨根系稳态O2流速的模式与群众杨不同。研究观察到ST处理后的胡杨根系氧内流速率增加(图3A)。在群众杨根系中,NaCl处理降低了根尖区的O2流速,但在伸长区的O2流速变化不明显(图3B)。为确定盐刺激的胡杨根系O2内流是否是线粒体呼吸被激活的结果,采用线粒体呼吸抑制剂NaN3抑制细胞色素途径。抑制剂NaN3显著降低了NaCl胁迫下胡杨根中O2的内流(图3C),表明ST处理激活了胡杨根细胞的线粒体呼吸。抑制剂NaN3能够显著降低ST处理下群众杨根系中O2的内流速率(图3D),表明植物的线粒体呼吸受到严重抑制。
图3. NaCl和线粒体呼吸抑制剂(NaN3)对胡杨和群众杨根部稳态O2流速的影响。
群众杨是一种盐敏感树种,因此在4周的处理中以50、100、150、200 mM递增的方式增加盐分。在增加盐分处理期间每周检查稳态O2流速。胡杨和群众杨在50 mM NaCl胁迫1周后,沿根轴O2内流速率增加,尽管耐盐杨树受到了更明显的刺激(图4A, B)。然而,在第2周100 mM NaCl胁迫下,群众杨不存在盐刺激的O2吸收(图4D)。本研究注意到,暴露在较高盐度下,即第3周150 mM NaCl和第4周200 mM NaCl,引起了群众杨中O2内流速率的显著下降,且这种影响在根尖区更为明显(图4F, H)。与盐敏感杨树相比,在盐胁迫期间,胡杨表现出沿根轴的O2内流增加,但刺激效果随盐度的增加而下降(图4A, C, E, G)。
图4. 长期增加NaCl对胡杨和群众杨根部O2流速的影响。
木本植物和草本植物的耐盐性在很大程度上是由Na+从细胞质中排出所介导的。为证实盐环境下胡杨根细胞稳定的线粒体呼吸是否能激活H+-ATPase以维持Na+稳态,本研究在盐胁迫下,检测了线粒体呼吸抑制剂NaN3对Na+外排和体内H+-ATPase活性的影响。NaCl(150 mM, 24 h)引起两种杨树根尖Na+外排显著增加(图5A)。值得注意的是,在NaCl处理下胡杨根系的Na+外排速率明显高于群众杨(图5A)。然而,抑制剂NaN3显著降低了NaCl胁迫下根系Na+外排速率(图5A),表明线粒体呼吸受到抑制后,Na+外排减少。在无盐对照条件下,NaN3没有明显改变Na+流速,这在两种杨树中几乎无法检测到(图5A)。
用NMT研究了NaCl胁迫下根中PM H+-ATPase的活性。NaCl处理(150 mM, 24 h)使H+的净内流速率在两个杨树根系中增加(图5B),这是Na+/H+跨PM逆向转运所致的(图5A, B)。NaN3增加了盐刺激下的H+内流(图5B),而抑制剂处理的根系中没有相应的增加Na+外排(图5A)。因此,抑制剂引起的H+内流主要是由质膜H+-ATPase产生的H+外排减少引起的。此外,NaN3导致两种杨树对照根中H+内流的增加(图5B),这是由于抑制剂处理下根中H+泵活性降低所致。
图5. NaCl和线粒体呼吸抑制剂(NaN3)对胡杨和群众杨根系Na+和H+稳态流速的影响。
图6. 植物根部检测图
其他实验结果
50 mM NaCl处理1周后,群众杨根部的整体呼吸量增加。然而,随着NaCl浓度和盐胁迫时间的增加,群众杨根部的呼吸速率呈下降趋势,呼吸速率在第3~4周达到最低值。与群众杨相反,NaCl处理的胡杨根的呼吸速率在处理1周后明显增加,在随后的3周盐胁迫中仍比对照植物高36~44%。
标题:Salt stress-induced H2O2 and Ca2+ mediate K+/Na+ homeostasis in Pyropia haitanensis
第一作者:王文磊、邢磊;通讯作者:谢潮添,集美大学
检测离子/分子指标
Na+,K+,H2O2,Ca2+
检测样品
坛紫菜叶状体
中文摘要
集美大学谢潮添教授课题组2019年在Algal Research(IF:4.008)上发表的题为“K+ and Na+ transport contribute to K+/Na+ homeostasis in Pyropia haitanensis under hypersaline stress”的文章首次从离子转运的角度报道了紫菜的耐盐机制。文章以坛紫菜为材料,结果表明,110‰盐胁迫下藻体仍能维持较高的K+/Na+。进一步通过NMT分析发现,藻体主要通过激活PM H+泵,驱动Na+/H+逆向转运体将细胞质外的Na+排出到质外体中,并通过去极化激活的外向整流型K+通道部分缓解K+的损失,从而维持较高的K+/Na+比值应对高盐胁迫。
为了了解NRT1.1在根系K+吸收中的作用,研究使用NMT系统检测了植物根系的K+流速,发现在2.0和0.05 mM K+培养基中,nrt1.1-1和chl1-5突变体根系伸长区和成熟区的K+净内流速率均低于Col-0植株的50%。相比之下,植物根系分生区净K+内流速率没有显著差异(图2B, C)。结果表明伸长区和成熟区是NRT1.1与根细胞K+吸收相关的靶区域。
标题:Soybean CHX-type ion transport protein GmSALT3 confers leaf Na+ exclusion via a root derived mechanism, and Cl- exclusion via a shoot derived process
使用100 mM NaCl处理发现,NIL-S地上部分、茎和叶中的Cl-、K+含量更高,K+/Na+比却降低了,NIL-T叶片中的K+/Na+比在胁迫第3 d后才明显升高。
盐处理10 d后,NIL-T的根、茎、叶干重明显增加。
100 mM NaCl处理4 d后发现,Na+、Cl-在NIL-S的所有气生组织中积累得更多。
在根部(主根和侧根),NIL-T比NIL-S积累的Cl-多。
100 mM NaCl处理4 d后,检测大豆茎韧皮部和木质部汁液中的离子浓度。与NIL-T相比,NIL-S的木质部汁液中的Na+浓度明显更高。与叶片的数据相反,NIL-S的木质部和韧皮部汁液中的Cl-浓度比NIL-T低。
对交互嫁接和自嫁接(self-grafted,对照)的植株进行100 mM NaCl处理8 d,结果发现在NIL-S砧木上嫁接NIL-T接穗,叶片Cl-含量比自嫁接NIL-S低。相反,当NIL-S接穗嫁接到NIL-T砧木上时,叶片中Cl-含量与自嫁接NIL-S相比差异不显著。与自接NIL-T植株相比,自接NIL-S植株的Cl-含量要高得多。
标题:Changes in Expression Level of OsHKT1;5 Alters Activity of Membrane Transporters Involved in K+ and Ca2+ Acquisition and Homeostasis in Salinized Rice Roots
研究采用非损伤微测技术(MIFE),测定了NIL(SKC1)水稻木质部薄壁组织的Na+流速。当向WT植株根中柱施加80 mM NaCl(模拟木质部汁液Na+浓度的增加)时,可测出强烈而持续的Na+吸收(图1A, C)。从功能上讲,这种吸收与根系木质部(通过HKT1;5或其他转运系统)对Na+的重吸收是一致的。然而,在NIL(SKC1)中,这种吸收是不存在的。相反,KD株系的木质部薄壁细胞对Na+的吸收甚至比WT系略高(图1A, C)。
标题:Dynamic changes of phosphatidylinositol and phosphatidylinositol 4-phosphate levels modulate H+-ATPase and Na+/H+antiporter activities to maintain ion homeostasis in Arabidopsis under salt stress
H+:7日龄拟南芥幼苗在含有75 mM NaCl的MS培养基中培养24 h。 Na+:7日龄拟南芥幼苗在含有100 mM NaCl的MS培养基中培养24 h。离子/分子流实验结果使用非损伤微测技术(NMT)检测Col-0, pis1-1, pis1-2,COM1 and COM2的H+流速。将7日龄幼苗转入含75 mM NaCl(pH 8.1)的MS培养基中培养24 h,测定根尖H+流速。pis1-1和pis1-2植物的H+流速与Col-0相比显著增加,而COM1和COM2植物的H+流速与Col-0植物相同(图1C, D)。因此,在PI含量减少的pis1突变体中,PM H+-ATPase活性增加,表明PI在体内抑制了PM H+-ATPase的活性。
6日龄草莓幼苗100 mM NaCl、100 μM NaCl+0.57 mM IAA、0.57 mM IAA处理3 d或6 d。离子/分子流实验结果不同处理下,Na+流速和Na+含量的变化趋势相同。处理6 d后,与对照相比,NaCl和NaCl+IAA均增加了根(图1D)和叶片(图1C)的Na+流速,但与NaCl+IAA处理相比,根系Na+流速对NaCl的响应更高。在叶片中,结果相反。NaCl处理下Na+流速增幅较大,叶片与根系相比增加了5.5倍,NaCl+IAA处理下叶片比根系增加11倍。
不同处理下K+流速与K+含量的变化趋势相同,NaCl处理下,叶片和根系K+流速均高于其他3个处理。
图1. 高盐条件下,第3天添加生长素可促进草莓根系Na+外排,第6天添加生长素可促进草莓叶片Na+外排。高盐度条件下草莓根系K+流速在第6天被生长素的添加所抑制。(A)(E)第3天草莓叶片Na+流速(A)和K+流速(E),(B)(F)第3天草莓根系Na+流速(B)和K+流速(F),(C)(G)第6天草莓叶片Na+流速(C)和K+流速(G),(D)(H)第6天草莓根系Na+流速(D)和K+流速(H)经NaCl(100 mM )、IAA(0.57 mM )及其组合处理。正值代表Na+、K+外排。
选取0.1 mM 水杨酸(SA)、蒸馏水(对照)处理,盐碱土培养3 d后的羊草种子测定Na+、K+、Ca2+流速,另外选取0.1 mM 水杨酸和对照浸种12 h后和盐碱土培养3 d后的羊草种子进行O2的测定。离子/分子流、离子浓度成像实验结果研究采用非损伤微测技术(NMT)测定萌发种子表面的O2内流。结果表明,萌发培养3 d后,0.1 mM SA处理下萌发种子的O2速率显著高于对照(图1H),但盐碱胁迫下种子的呼吸强度有所降低。此外,0.1 mM SA处理后O2内流速率显著高于对照(图1I),说明SA可以提高盐碱胁迫下羊草种子的发芽率和活力。
图1. 羊草种子O2吸收。
为了进一步探究为什么用0.1 mM SA处理会减少Na+的含量,而增加Ca2+、K+的积累,研究用NMT测量了用0.1 mM SA处理和对照组在培养3 d后的发芽种子的胚顶部的Na+、K+和Ca2+的流速和浓度空间成像。结果显示,0.1 mM SA处理和对照组都明显表现出Na+的外排(图2A),但0.1 mM SA处理表现出比对照组更高的Na+外排,Na+的平均速率达到1144 pmol cm-2⋅s-1,与对照组相比,增加了4.66倍(图2B)。Na+浓度空间成像表明,虽然对照处理下种子表面Na+含量增加,但种子表面Na+积累量明显低于SA处理(图2C)。与对照K+的外排不同,0.1 mM SA处理下萌发的种子虽然K+流速较低,但仍然是内流(图2D),种子胚顶部的平均内流速率仅为0.68 pmol cm-2·s-1。值得注意的是,对照组中K+平均外排速率达到341.81 pmol cm-2⋅s-1(图2E),对照组中萌发种子表面的K+浓度也明显低于SA处理时的浓度,表明对照组中发生了巨大的K+外排(图2F)。Ca2+流速数据表明,在用0.1 mM SA处理和对照组中,检测到稳定的Ca2+外排(图2G)。与对照组相比,用0.1 mM SA处理后的Ca2+外排速率明显降低(图2H),用0.1 mM SA处理的种子表面的Ca2+浓度也比对照组低(图2I)。图2. 在盐碱胁迫下,外源SA改变了羊草发芽种子表面的离子流速。(A) Na+的瞬时流速 (B) Na+平均流速 (C) 种子表面Na+浓度空间成像(0-150 μm)。(D) K+的瞬时流速 (E) K+平均流速 (F) 种子表面K+浓度的空间成像(0-150 μm)。(G) Ca2+的瞬时流速 (H) Ca2+平均流速 (I) 种子表面Ca2+浓度空间成像(0-150 μm)。
其他实验结果
外源SA提高了羊草种子的活力和发芽率。
盐碱胁迫下外源SA影响了种子休眠。
盐碱胁迫下外源SA激活了羊草种子抗氧化酶系统。
外源SA缓解了盐碱胁迫对质膜的损伤。
盐碱胁迫下外源SA改变了Na+、K+和Ca2+的积累。
盐碱胁迫下外源SA触发转录水平的变化。
结论综上所述,合理剂量的外源SA可以作为渗透调节剂促进羊草种子萌发,0.1 mM SA的施用浓度有效提高了盐碱胁迫下羊草种子的活力和萌发。通过增加内源SA和O2流入,SA在平衡羊草萌发种子中的内源性激素和渗透物方面发挥了重要的渗透调节作用(图3)。此外,外源SA通过调节信号因子H2O2、渗透物质以及Na+、K+、Ca2+等离子在羊草种子萌发过程中的积累,提高抗氧化酶活性,保护细胞膜的完整性。本研究表明,SA主要通过调控盐碱胁迫下羊草种子萌发过程中离子分泌和渗透调节物质积累途径发挥作用,外源SA将为促进盐碱化土壤羊草种子萌发和繁殖提供有效参考。调节外源SA介导的植物种子的生理和渗透响应,也揭示了在非生物胁迫下减轻渗透胁迫对发芽种子的损害的一个启示。图3. 盐碱胁迫下,SA介导羊草种子萌发的一种假设调控途径。
测试液
0.1 mM CaCl2, 0.1 mM KCl, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, pH 6.0
标题:Tissue tolerance mechanisms conferring salinity tolerance in a halophytic perennial species Nitraria sibirica Pall.
作者:中国林科院国家林业和草原局盐碱地研究中心张华新、杨秀艳、唐晓倩、张会龙
检测离子/分子指标
K+、Na+、H+
检测样品
西伯利亚白刺叶肉组织
中文摘要
植物的耐盐性依赖于不同组织和器官的协调运转。组织耐盐性是赋予植物适应盐环境的关键性状之一。这一特性意味着在代谢活跃的细胞中能够维持较低的胞质Na+/K+比值。本研究以多年生木本盐生植物西伯利亚白刺(Nitraria sibirica)为材料,探讨其耐盐性机制。结果表明,100~200 mM NaCl处理刺激了幼苗的生长。离子分布结果表明,叶片起到Na+库的作用,而植物根系具有优越的保K+能力。从土壤中吸收的过量Na+主要转运到地上部分,最终被区隔在叶肉细胞的液泡中。因此,在盐胁迫下西伯利亚白刺能够在组织和细胞水平上特异性保持K+/Na+的最适平衡。为此,西伯利亚白刺叶肉细胞中液泡H+-ATPase和H+-PPase酶活性升高, NsVHA、NsVP1和NsNHX1基因的表达上调。NsVHA、NsVP1和NsNHX1介导的叶肉液泡Na+区隔化降低了细胞质中Na+浓度,抑制了K+的流失。同时,西伯利亚白刺在转录水平上调TPK的表达,促进K+从液泡向细胞质转移,有助于维持细胞质中K+稳态。综上表明,西伯利亚白刺的液泡Na+区隔化和细胞内K+稳态等组织耐受特性对西伯利亚白刺适应土壤盐渍化具有重要作用。
当15%PEG实施胁迫时,烟草根尖Ca2+外排速率瞬时增加,转基因株系的Ca2+外排速率是WT植株的0.9~1.4倍(图1A)。在200 mM NaCl胁迫下,转基因植株也观察到较高的Ca2+外排速率(142.0~156.8%)(图1C),结合[Ca2+]cyt结果说明CbFAD3-过表达植物中PM Ca2+-ATPase的持续激活改变了早期胁迫时诱导的Ca2+信号传递。
标题:Leaf mesophyll K+ and Cl- fluxes and reactive oxygen species production predict rice salt tolerance at reproductive stage in greenhouse and field conditions
标题:The positive effectof salinity on nitrate uptake in Suaeda salsa
作者:山东师范大学宋杰、刘冉冉、Bing Cui
检测离子/分子指标
NO3-、H+
检测样品
盐地碱蓬
中文摘要
硝酸盐在盐生植物的耐盐性中起着营养和渗透双重作用。然而,盐生植物在盐碱条件下如何吸收NO3-仍不清楚。在0.5 mM的NO3--N条件下,用0、200和500 mM的NaCl处理盐地碱蓬幼苗,同时添加或不添加Na3VO4(质膜H+-ATPase抑制剂)处理24 h。200 mM NaCl处理上调了根中硝酸盐转运蛋白2.1(SsNRT2.1)的基因表达,增加了根中H+和NO3-的内流,以及叶和根中15NO3-的积累。SsNRT2.1在200 mM NaCl+Na3VO4处理下的表达量显著高于不加Na3VO4处理,而在叶片和根中15NO3-的积累量则相反。在200mM NaCl下,施加Na3VO4对根系H+净流速无显著影响,但诱导根系NO3-净外排。盐度可直接激活SsNRT2.1的表达,并通过增加PM H+-ATPase泵入H+促进盐地碱蓬对NO3-的吸收,这可能解释了为什么某些盐生植物在低NO3-和高盐度条件下吸收和积累高浓度NO3-的原因。
离子/分子流实验处理方法
①0、200、500 mM NaCl处理1 d。 ②0+150 μM Na3VO4、200+150 μM Na3VO4、500 mM NaCl+150 μM Na3VO4处理1 d。
离子/分子流实验结果
与0 mM NaCl相比,200 mM NaCl明显诱导净NO3-内流。然而,500 mM NaCl诱导净NO3-外排(图1a, b)。当加入150 μM Na3VO4时,0、200和500 mM NaCl诱导了NO3-净外排,特别是在500 mM NaCl处理下(图1a, b)。
在0 mM NaCl+0 mM Na3VO4处理下H+外排,在200、500 mM NaCl和0+150 μM Na3VO4、200+150 μM Na3VO4和500 mM NaCl+150 μM Na3VO4处理时H+内流(图1c, d)。与0 mM NaCl相比,200 mM NaCl显著诱导了H+的内流。与不添加Na3VO4的处理相比,添加150 μM Na3VO4显著诱导了所有NaCl浓度处理下的净H+内流(图1c, d)。
在不同浓度NaCl处理下,根和叶中15NO3-的积累趋势与SsNRT2.1的相对表达量一致。盐分增加了根和叶中15NO3-的积累,尤其是在200 mM NaCl下。添加Na3VO4降低了根系和叶片中15NO3-的积累。
无论Na3VO4怎么处理,盐度对根和地上部分的干重影响较小。添加Na3VO4会显著降低0 mM NaCl处理下根和地上部分的干重。
结论
200 mM NaCl增加了盐地碱蓬对NO3-的吸收,这可能是由于PM H+-ATPase增加了H+的泵入。同时,盐度对SsNRT2.1的表达有积极影响。这表明盐度可能直接激活NRT的某些基因,并通过增加PM H+-ATPase对H+的泵送来促进盐生植物盐地碱蓬的NO3-吸收(图2)。这一特性可能解释了为什么盐地碱蓬和其他盐生植物能够在盐度下吸收和积累高浓度的NO3-,即它们能够耐受高盐度,在200~300 mM NaCl下产生最高生物量。
图2. NaCl对盐地碱蓬NO3-吸收的正效应模型。
测试液
NO3-:0.5 mM KNO3, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
H+:0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, pH 6.0
标题:Phosphatidylserine Synthase from Salicornia europaea Is Involved in Plant Salt Tolerance by Regulating Plasma Membrane Stability
作者:中科院植物所李银心、吕素莲、台方
检测离子/分子指标
K+
检测样品
盐角草根细胞
中文摘要
盐诱导的脂类改变在许多植物物种中已有报道,然而,脂类生物合成和代谢如何调控,脂类在植物耐盐性中如何发挥作用的研究却少得多。在本研究中,盐角草细胞质膜(PM)中磷脂酰丝氨酸(PS)含量明显高于拟南芥。随后从盐角草中分离到一个编码磷脂酰丝氨酸合成酶(PSS)的基因,命名为SePSS。多重比对和系统发育分析表明,SePSS属于碱基交换型PSS,位于内质网。在400或800 mM NaCl胁迫下,SePSS在盐角草悬浮细胞中的失活导致PS含量降低,细胞存活率降低,PM去极化和K+外排增加。相比之下,SePSS的上调导致拟南芥PS和磷脂酰乙醇胺(PE)水平升高,耐盐性增强,同时转基因株系中活性氧积累比WT低,膜损伤较少,PM去极化较少,K+/Na+较高。这些结果表明,PS水平与植物耐盐性呈正相关,SePSS通过调节PS水平参与植物耐盐性,进而调节PM电位和通透性,维持离子稳态。本研究的工作内容为改善植物在多重胁迫下的生长提供了一个潜在的策略。
离子/分子流实验处理
0、400、800 mM NaCl处理2 h
离子/分子流实验结果
盐胁迫下,植物的PM常常会发生去极化,导致K+从细胞中渗出。为了研究SePSS在盐胁迫下调节膜电位的可能作用,分别用0、400和800 mM NaCl处理空载体(empty vector,EV)细胞和SePSS-RNAi细胞。采用非损伤微测技术(NMT)检测K+净流速,与无盐处理相比,400和800 mM NaCl处理使EV细胞K+内流减少,800 mM NaCl处理使SePSS-RNAi细胞K+由内流转为外排(图1)。这些结果表明,敲除SePSS可能会加剧NaCl诱导的PM去极化,从而导致K+从细胞中渗漏。
水培条件下CDs通过增强Ca2+信号和Na+稳态来提高甘薯植株的耐盐性。盐处理24 h后,甘薯根尖中IbSOS3和IbSOS2的表达水平提高了约1.9-2.0倍;CDs激活CNGCs,增强根尖(伸长区)中[Ca2+]cyt依赖的SOS通路,从而加速Na+的外排;在盐(150 mm NaCl)处理12天,CDs处理后根、茎和叶组织中Na+的积累分别减少了41%、32%和49%,因此,CDs大大提高了甘薯植株的耐盐性。
标题:The genome of the recretohalophyte Limonium bicolor provides insights into salt gland development and salinity adaptation during terrestrial evolution
作者:山东师范大学王宝山、陈敏、袁芳、王茜、赵博庆、徐晓静、北京贝瑞和康生物技术有限公司史淼
检测离子/分子指标
Na+
检测样品
二色补血草盐腺
中文摘要
盐生植物会进化出专门应对高盐度的方式。极端盐生植物二色补血草(Limonium bicolor)表皮缺乏毛状体,但有盐腺,可排出钠等有害离子,避免盐害。本文利用Illumina短序列、单分子实时长序列、染色体构象捕获(Hi-C)数据和Bionano基因组图谱,报道了一个高质量、2.92Gb染色体规格的二色补血草基因组组装,极大地丰富了具有多细胞盐腺的泌盐盐生植物的基因组信息。虽然二色补血草基因组具有与拟南芥(Arabidopsis thaliana)毛状体命运基因相似的基因,但其与命运决定基因GLABRA3、ENHANCER of GLABRA3、GLABRA2、TRANSPARENT TESTA GLABRA2和SIAMESE缺乏同源性,为该物种缺乏毛状体提供了分子解释。在毛状体经典同源基因中,发现了控制盐腺发育的关键基因LbHLH和LbTTG1的突变显著破坏了盐腺的启动、盐的分泌和盐的耐受性。这为长期存在的盐腺和毛状体可能有共同起源的假设提供了基因支持。此外,二色补血草在与苦荞麦分化后发生了全基因组复制事件,这可能是苦荞适应高盐环境的原因之一。二色补血草的基因组资源为植物耐盐机制的研究提供了丰富的信息,有助于耐盐作物的工程化。
经过7 d的200 mM NaCl处理后,与WT和Mock株系(CR和OE)相比,Lbttg1-cr和Lbhlh-cr两个株系比盐处理前表型增强,具体表现在全株叶片和根系发育上。NaCl处理前后测定根长和单叶面积。尽管盐处理后所有株系均表现出根系伸长和叶片展开明显,但Lbttg1-cr在这两个指标的增加率上均显著优于LbTTG1-OE,Lbhlh-cr的增加率也高于LbHLH-OE。这说明盐处理下CR株系的生长速度明显快于OE株系。
在用50 mM NaCl处理的根中,低氧导致rbohD突变体根部的净Na+和Cl-吸收瞬时增加(图2)。除了成熟区低氧诱导的Na+吸收外,WT根中没有观察到这种效应(图2B)。WT根中的净Na+内流量也显著低于rbohD突变体(图2B)。在这两个区域中,没有测量到对低氧处理响应的净K+流速的显著变化(图3A,B),并且低氧胁迫的开始引起了两个区域向瞬时净Ca2+流出的转变(图3C,D),两个基因型之间没有显着差异。然而,盐胁迫48h后,WT比rbohD突变体在伸长区有更多的Ca2+内流(图3C)。
中国林科院亚热带林业研究所卓仁英研究员课题组在Environmental and Experimental Botany上发表了一篇文章,题目为“Pathogenesis-related protein PR10 fromSalix matsudanaKoidz exhibits resistance to salt stress intransgenicArabidopsis thaliana”,主要探究PR蛋白在植物耐盐机制中起到的作用。
前期的比较蛋白质组学分析表明:沙柳PR蛋白(SmPR10)较为丰富,经过100 mM NaCl处理后表达上调。本实验以沙柳为材料,克隆并鉴定了SmPR10基因,以验证其在耐盐性中的作用。SmPR10的氨基酸序列与紫苏柳和毛白杨的PR蛋白的序列同源性分别为98%和93%。SmPR10定位在拟南芥原生质体的胞质中,根的转录及蛋白水平较高,且100mM NaCl处理后表达上调。免疫定位分析发现,韧皮部纤维细胞和根木质部中特异性的检测到SmPR10。而且,SmPR10的异质过表达提高了转基因拟南芥的耐盐性,具体表现在根长度、根数量、Na+流速、以及叶绿素含量、MDA含量、电导率等生理参数及SOD和POD酶活性水平。
Plants have evolved complex mechanisms that allow them to withstand multiple environmental stresses, including biotic and abiotic stresses.
Here, we investigated the interaction between herbivore exposure and salt stress of Ammopiptanthus nanus, a desert shrub. We found that jasmonic acid (JA) was involved in plant responses to both herbivore attack and salt stress, leading to an increased NaCl stress tolerance for herbivore-pretreated plants, and increase in K+/Na+ ratio in roots. Further evidence revealed the mechanism by which herbivore improved plant NaCl tolerance. Herbivore pretreatment reduced K+ efflux and increased Na+ efflux in plants subjected to long-term, short-term, or transient NaCl stress.
Moreover, herbivore pretreatment promoted H+ efflux by increasing plasma membrane H+-ATPase activity. This H+ efflux creates a transmembrane proton motive force that drives the Na+/H+ antiporter to expel excess Na+ into the external medium. In addition, high cytosolic Ca2+ was observed in the roots of herbivore-treated plants exposed to NaCl, and this effect may be regulated by H+-ATPase.
Taken together, herbivore exposure enhances A. nanus tolerance to salt stress by activating the JA signalling pathway, increasing plasma membrane H+-ATPase activity, promoting cytosolic Ca2+ accumulation, and then restricting K+ leakage and reducing Na+ accumulation in the cytosol.
NH4+: 0.1 mM NH4NO3, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
NO3-: 0.1 mM NH4NO3, 1.0 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
作者:山东农业大学林学院马风云、刘秀梅
英文摘要
A potted experiment with Populus × euramericana ‘Neva’ was carried out to assess whether there are positive effects of magnetic treatment of saline water (MTSW) on nitrogen metabolism under controlled conditions in a greenhouse.
Growth properties, nitrogen contents, enzyme activities and metabolite concentrations were determined based on field experiments and laboratory analysis after a 30-day treatment.
The results were as follows: (1) Biomass accumulation, root morphological properties and total nitrogen content were improved by MTSW. (2) Magnetization led to a greater increase in nitrate-nitrogen (NO3−-N) content in roots than in leaves, accompanied by greater NO3− efflux and activated nitrate reductase. (3) MTSW led to a higher ammonium-nitrogen (NH4+-N) content and greater uptake of net NH4+ in the leaves than that in the roots. (4) Magnetization stimulated glutamine synthase, glutamate dehydrogenase and glutamate synthase activities, whereas the concentrations of glutathione and oxidized glutathione were increased in leaves but decreased in roots, and the total glutathione content was increased.
Overall, these results indicated some beneficial impacts of MTSW on nitrogen translocation under field conditions, especially for equilibrating the distribution of NO3−-N and NH4+-N. Moreover, these findings confirmed the potential of using low-quality water for agriculture.
NH4+、NO3-流实验测试液成份: NH4+: 0.1 mM NH4NO3, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5 NO3-: 0.1 mM NH4NO3, 1.0 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 5.5
作者:山东农业大学林学院马风云、刘秀梅
英文摘要
A potted experiment with Populus × euramericana ‘Neva’ was carried out to assess whether there are positive effects of magnetic treatment of saline water (MTSW) on nitrogen metabolism under controlled conditions in a greenhouse. Growth properties, nitrogen contents, enzyme activities and metabolite concentrations were determined based on field experiments and laboratory analysis after a 30-day treatment.
The results were as follows: (1) Biomass accumulation, root morphological properties and total nitrogen content were improved by MTSW. (2) Magnetization led to a greater increase in nitrate-nitrogen (NO3−-N) content in roots than in leaves, accompanied by greater NO3− efflux and activated nitrate reductase. (3) MTSW led to a higher ammonium-nitrogen (NH4+-N) content and greater uptake of net NH4+ in the leaves than that in the roots. (4) Magnetization stimulated glutamine synthase, glutamate dehydrogenase and glutamate synthase activities, whereas the concentrations of glutathione and oxidized glutathione were increased in leaves but decreased in roots, and the total glutathione content was increased.
Overall, these results indicated some beneficial impacts of MTSW on nitrogen translocation under field conditions, especially for equilibrating the distribution of NO3−-N and NH4+-N. Moreover, these findings confirmed the potential of using low-quality water for agriculture.
Mean net K+ fluxmeasured from the biofilms in response to treatment with 5 mMand 10mM TEA
英文摘要
Bacteria in biofilms are able to utilize potassium ion channel mediated electrical signaling to achieve cell–cell communication. However, it remains unclear whether these signals play a role in Geobacter sp.when surrounded by an intense electric field.
This study used a potassium channel blocker (tetraethylammonium, TEA) that interfered with the release of K+ but not bacterial growth to demonstrate that potassium ion channel-mediated electrical signaling affected the formation and electroactivity of Geobacter sulfurreducens. The results showed that 5 mM TEA slowed the formation of Geobacter sulfurreducens biofilm, and the current density was ~50% lower than in the control.
The electrochemical analyses showed that the electroactivity of the biofilms with TEA addition was inferior. In particular, the micrometer- scale biofilm with TEA exhibited fewer high current peaks, and the species of outermost groups that participated in the electron transfer in Geobacter sulfurreducens biofilms was different from the control.
This work provides initial evidence to reveal the role of potassium channels in Geobacter sulfurreducens electroactive biofilms.
This study investigated the influences of cetyltrimethyl trimethyl ammonium chloride (CTAC), an emerging pollutant quaternary ammonium compound (QAC) in municipal effluents, on the transfer and uptake of NH4+ by Chlorella vulgaris F1068 cells removed EPS artificially (EPS-R) and coated EPS naturally (EPS-C) under different scenarios (e.g., the presence or absence of CTAC, different photoperiod sequences (light 12 h: dark 12 h or dark 12 h: light 12 h)).
The results showed that the removal of EPS increased the transfer and uptake of NH4+ but the presence of EPS caged NH4+ and effectively weakened the stress of CTAC (<0.5 mg/L) on NH4+ uptake. The main mechanism was considered that CTAC in the concentration range from 0.1 to 0.5 mg/L induced an increased amount of polysaccharide and protein in EPS and thus protected algal normal physiological functions (including cell membrane permeability and glutamine synthetase activity) from the damage of CTAC (0.1 to 0.5 mg/L) regardless of the photoperiod sequences.
Thereby, the findings of this study provided an insight into the role of algal EPS in transfer and uptake of nutrients under the coexisted toxics for the future algae-based sewage treatment application.
结果表明:在没有CTAC的6小时光照下,EPS-C细胞或EPS-R细胞的NH4+通量分别达到-1.87ng /(cm2·s)和-2.63ng /(cm2·s)。当添加0.5 mg / L的CTAC时,EPS-C或EPS-R细胞的NH4+通量急剧下降至-0.94 ng /(cm2·s)和-0.73 ng /(cm2·s)。相反,当EPS-R细胞和EPS-C细胞在黑暗中培养6小时无论CTAC存在与否,EPS-C细胞和EPS-R细胞的NH4+流速从负值转换为正值,表明NH4+从细胞内环境流出到培养基。
The impact of freshwater (FW) salinization on osmoregulation as well as tracheal gill morphology and function was examined in nymphs of the mayfly Hexagenia rigida following exposure to salt contaminated water (SCW, 7.25 g/l NaCl) for a 7-day period.
Ionoregulatory homeostasis was perturbed in SCW exposed H. rigida nymphs as indicated by increased hemolymph Na+, K+ and Cl− levels as well as hemolymph pH and water content. Despite this, SCW did not alter gill Na+-K+-ATPase (NKA) or V-type H+-ATPase (VA) activity. In addition, NKA and VA immunolocalization in gill ionocytes did not show alterations in enzyme location or changes in ionocyte abundance.
The latter observation was confirmed using scanning electron microscopy (SEM) to examine exposed tracheal gill ionocyte numbers. Ionocyte surface morphometrics also revealed that SCW did not change individual ionocyte surface area or ionocyte fractional surface area. Nevertheless, analysis of Na+ movement across the tracheal gill of mayfly nymphs using scanning ion-selective electrode technique indicated that FW nymphs acquired Na+ from surrounding water, while tracheal gills of SCW nymphs had the capacity to secrete Na+.
Because Na+ secretion across the gill of SCW-exposed animals occurred in the absence of any change in (1) NKA and VA activity or (2) ionocyte numbers/surface exposure, it was reasoned that Na+ movement across the gill of SCW animals may be occurring, at least in part, through the paracellular pathway. The ultrastructure of tracheal gill septate junctions (SJs) supported this idea as they exhibited morphological alterations indicative of a leakier pathway. Data provide a first look at alterations in osmoregulatory mechanisms that allow H. rigida nymphs to tolerate sub-lethal salinization of their surroundings.
中文摘要(谷歌机翻)
在暴露于盐污染的水(SCW,7.25g / l NaCl)7天后,在may fly(Hexflynia rigida)的若虫中检查淡水(FW)盐化对渗透调节以及气管鳃形态和功能的影响。
为了进一步了解SLAH3 S601位点的生理作用,研究采用非损伤微测技术(NMT)对硝酸盐流速进行了分析。为检验Cl-是否干扰NMT系统中NO3-的检测,在无幼苗的情况下分别检测测试液1(1 mM KNO3, 0.1mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 6.0)和测试液2(1 mM KNO3, 1.1 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 6.0)中NO3-的浓度和净流速。Cl-的存在不干扰NO3-的检测(图2)。其次,本研究检测了根尖附近成熟区的NO3-净流速(图1A,图3A)。对Col-0、slah3-3、slah3-4幼苗和所有互补株系在1/2 MS培养基上生长8 d后转入高NH4+/低pH条件(1 mM NO3-, 10 mM NH4+, pH 4.5)或非高NH4+/低pH条件(1 mM NO3-, 1 mM NH4+, pH 5.7)2 h后进行检测。在6 min内检测到来自植物根系的NO3-流速(图1B,图3B)。在高NH4+/低pH胁迫下,Col-0的NO3-外排速率平均值约为93 pmol cm-2s-1,slah3突变体的NO3-外排速率平均值约为0 pmol cm-2s-1。slah3-4背景下的互补株系SLAH3和SLAH3 S601A显示出与Col-0植株类似的硝酸盐外排。相比之下,slah3-4背景下互补株系SLAH3 S601D的硝酸盐外排与slah3突变体相似(图1B)。此外,在非高NH4+/低pH胁迫下,所有植物的硝酸盐外排相似,NO3-外排速率的平均值均在0 pmol cm-2s-1左右(图3)。这些结果表示SLAH3的S601在高NH4+/低pH胁迫下对硝酸盐外排起重要的调节作用。
为了进一步了解SLAH3 S601位点的生理作用,研究采用非损伤微测技术(NMT)对硝酸盐流速进行了分析。为检验Cl-是否干扰NMT系统中NO3-的检测,在无幼苗的情况下分别检测测试液1(1 mM KNO3, 0.1mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 6.0)和测试液2(1 mM KNO3, 1.1 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 6.0)中NO3-的浓度和净流速。Cl-的存在不干扰NO3-的检测(图2)。其次,本研究检测了根尖附近成熟区的NO3-净流速(图1A,图3A)。对Col-0、slah3-3、slah3-4幼苗和所有互补株系在1/2 MS培养基上生长8 d后转入高NH4+/低pH条件(1 mM NO3-, 10 mM NH4+, pH 4.5)或非高NH4+/低pH条件(1 mM NO3-, 1 mM NH4+, pH 5.7)2 h后进行检测。在6 min内检测到来自植物根系的NO3-流速(图1B,图3B)。在高NH4+/低pH胁迫下,Col-0的NO3-外排速率平均值约为93 pmol cm-2s-1,slah3突变体的NO3-外排速率平均值约为0 pmol cm-2s-1。slah3-4背景下的互补株系SLAH3和SLAH3 S601A显示出与Col-0植株类似的硝酸盐外排。相比之下,slah3-4背景下互补株系SLAH3 S601D的硝酸盐外排与slah3突变体相似(图1B)。此外,在非高NH4+/低pH胁迫下,所有植物的硝酸盐外排相似,NO3-外排速率的平均值均在0 pmol cm-2s-1左右(图3)。这些结果表示SLAH3的S601在高NH4+/低pH胁迫下对硝酸盐外排起重要的调节作用。
标题:Salt stress-induced H2O2 and Ca2+ mediate K+/Na+ homeostasis in Pyropia haitanensis
第一作者:王文磊、邢磊;通讯作者:谢潮添,集美大学
检测离子/分子指标
Na+,K+,H2O2,Ca2+
检测样品
坛紫菜叶状体
中文摘要
集美大学谢潮添教授课题组2019年在Algal Research(IF:4.008)上发表的题为“K+ and Na+ transport contribute to K+/Na+ homeostasis in Pyropia haitanensis under hypersaline stress”的文章首次从离子转运的角度报道了紫菜的耐盐机制。文章以坛紫菜为材料,结果表明,110‰盐胁迫下藻体仍能维持较高的K+/Na+。进一步通过NMT分析发现,藻体主要通过激活PM H+泵,驱动Na+/H+逆向转运体将细胞质外的Na+排出到质外体中,并通过去极化激活的外向整流型K+通道部分缓解K+的损失,从而维持较高的K+/Na+比值应对高盐胁迫。
标题:Dynamic changes of phosphatidylinositol and phosphatidylinositol 4-phosphate levels modulate H+-ATPase and Na+/H+antiporter activities to maintain ion homeostasis in Arabidopsis under salt stress
H+:7日龄拟南芥幼苗在含有75 mM NaCl的MS培养基中培养24 h。 Na+:7日龄拟南芥幼苗在含有100 mM NaCl的MS培养基中培养24 h。离子/分子流实验结果使用非损伤微测技术(NMT)检测Col-0, pis1-1, pis1-2,COM1 and COM2的H+流速。将7日龄幼苗转入含75 mM NaCl(pH 8.1)的MS培养基中培养24 h,测定根尖H+流速。pis1-1和pis1-2植物的H+流速与Col-0相比显著增加,而COM1和COM2植物的H+流速与Col-0植物相同(图1C, D)。因此,在PI含量减少的pis1突变体中,PM H+-ATPase活性增加,表明PI在体内抑制了PM H+-ATPase的活性。
6日龄草莓幼苗100 mM NaCl、100 μM NaCl+0.57 mM IAA、0.57 mM IAA处理3 d或6 d。离子/分子流实验结果不同处理下,Na+流速和Na+含量的变化趋势相同。处理6 d后,与对照相比,NaCl和NaCl+IAA均增加了根(图1D)和叶片(图1C)的Na+流速,但与NaCl+IAA处理相比,根系Na+流速对NaCl的响应更高。在叶片中,结果相反。NaCl处理下Na+流速增幅较大,叶片与根系相比增加了5.5倍,NaCl+IAA处理下叶片比根系增加11倍。
不同处理下K+流速与K+含量的变化趋势相同,NaCl处理下,叶片和根系K+流速均高于其他3个处理。
图1. 高盐条件下,第3天添加生长素可促进草莓根系Na+外排,第6天添加生长素可促进草莓叶片Na+外排。高盐度条件下草莓根系K+流速在第6天被生长素的添加所抑制。(A)(E)第3天草莓叶片Na+流速(A)和K+流速(E),(B)(F)第3天草莓根系Na+流速(B)和K+流速(F),(C)(G)第6天草莓叶片Na+流速(C)和K+流速(G),(D)(H)第6天草莓根系Na+流速(D)和K+流速(H)经NaCl(100 mM )、IAA(0.57 mM )及其组合处理。正值代表Na+、K+外排。
The dual-affinity nitrate transceptor NITRATE TRANSPORTER 1.1 (NRT1.1) has two modes of transport and signaling, governed by threonine101 (T101) phosphorylation. NRT1.1 regulates lateral root (LR) development by modulating nitrate-dependent basipetal auxin export and nitrate-mediated signal transduction.
Here, using the Arabidopsis thaliana NRT1.1T101D phosphomimetic and NRT1.1T101A non-phosphorylatable mutants, we found that the phosphorylation state of NRT1.1 plays a key role in NRT1.1 function during LR development. Single-particle tracking revealed that phosphorylation affected NRT1.1 spatiotemporal dynamics. The phosphomimetic NRT1.1T101D form showed fast lateral mobility and membrane partitioning that facilitated auxin flux under low-nitrate conditions.
By contrast, non-phosphorylatable NRT1.1T101A showed low lateral mobility and oligomerized at the plasma membrane (PM), where it induced endocytosis via the clathrin-mediated endocytosis and microdomain-mediated endocytosis pathways under high-nitrate conditions.
These behaviors promoted LR development by suppressing NRT1.1-controlled auxin transport on the PM and stimulating Ca2+-ARABIDOPSIS NITRATE REGULATED 1 (ANR1) signaling from the endosome.
选取0.1 mM 水杨酸(SA)、蒸馏水(对照)处理,盐碱土培养3 d后的羊草种子测定Na+、K+、Ca2+流速,另外选取0.1 mM 水杨酸和对照浸种12 h后和盐碱土培养3 d后的羊草种子进行O2的测定。离子/分子流、离子浓度成像实验结果研究采用非损伤微测技术(NMT)测定萌发种子表面的O2内流。结果表明,萌发培养3 d后,0.1 mM SA处理下萌发种子的O2速率显著高于对照(图1H),但盐碱胁迫下种子的呼吸强度有所降低。此外,0.1 mM SA处理后O2内流速率显著高于对照(图1I),说明SA可以提高盐碱胁迫下羊草种子的发芽率和活力。
图1. 羊草种子O2吸收。
为了进一步探究为什么用0.1 mM SA处理会减少Na+的含量,而增加Ca2+、K+的积累,研究用NMT测量了用0.1 mM SA处理和对照组在培养3 d后的发芽种子的胚顶部的Na+、K+和Ca2+的流速和浓度空间成像。结果显示,0.1 mM SA处理和对照组都明显表现出Na+的外排(图2A),但0.1 mM SA处理表现出比对照组更高的Na+外排,Na+的平均速率达到1144 pmol cm-2⋅s-1,与对照组相比,增加了4.66倍(图2B)。Na+浓度空间成像表明,虽然对照处理下种子表面Na+含量增加,但种子表面Na+积累量明显低于SA处理(图2C)。与对照K+的外排不同,0.1 mM SA处理下萌发的种子虽然K+流速较低,但仍然是内流(图2D),种子胚顶部的平均内流速率仅为0.68 pmol cm-2·s-1。值得注意的是,对照组中K+平均外排速率达到341.81 pmol cm-2⋅s-1(图2E),对照组中萌发种子表面的K+浓度也明显低于SA处理时的浓度,表明对照组中发生了巨大的K+外排(图2F)。Ca2+流速数据表明,在用0.1 mM SA处理和对照组中,检测到稳定的Ca2+外排(图2G)。与对照组相比,用0.1 mM SA处理后的Ca2+外排速率明显降低(图2H),用0.1 mM SA处理的种子表面的Ca2+浓度也比对照组低(图2I)。图2. 在盐碱胁迫下,外源SA改变了羊草发芽种子表面的离子流速。(A) Na+的瞬时流速 (B) Na+平均流速 (C) 种子表面Na+浓度空间成像(0-150 μm)。(D) K+的瞬时流速 (E) K+平均流速 (F) 种子表面K+浓度的空间成像(0-150 μm)。(G) Ca2+的瞬时流速 (H) Ca2+平均流速 (I) 种子表面Ca2+浓度空间成像(0-150 μm)。
其他实验结果
外源SA提高了羊草种子的活力和发芽率。
盐碱胁迫下外源SA影响了种子休眠。
盐碱胁迫下外源SA激活了羊草种子抗氧化酶系统。
外源SA缓解了盐碱胁迫对质膜的损伤。
盐碱胁迫下外源SA改变了Na+、K+和Ca2+的积累。
盐碱胁迫下外源SA触发转录水平的变化。
结论综上所述,合理剂量的外源SA可以作为渗透调节剂促进羊草种子萌发,0.1 mM SA的施用浓度有效提高了盐碱胁迫下羊草种子的活力和萌发。通过增加内源SA和O2流入,SA在平衡羊草萌发种子中的内源性激素和渗透物方面发挥了重要的渗透调节作用(图3)。此外,外源SA通过调节信号因子H2O2、渗透物质以及Na+、K+、Ca2+等离子在羊草种子萌发过程中的积累,提高抗氧化酶活性,保护细胞膜的完整性。本研究表明,SA主要通过调控盐碱胁迫下羊草种子萌发过程中离子分泌和渗透调节物质积累途径发挥作用,外源SA将为促进盐碱化土壤羊草种子萌发和繁殖提供有效参考。调节外源SA介导的植物种子的生理和渗透响应,也揭示了在非生物胁迫下减轻渗透胁迫对发芽种子的损害的一个启示。图3. 盐碱胁迫下,SA介导羊草种子萌发的一种假设调控途径。
测试液
0.1 mM CaCl2, 0.1 mM KCl, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, pH 6.0
当15%PEG实施胁迫时,烟草根尖Ca2+外排速率瞬时增加,转基因株系的Ca2+外排速率是WT植株的0.9~1.4倍(图1A)。在200 mM NaCl胁迫下,转基因植株也观察到较高的Ca2+外排速率(142.0~156.8%)(图1C),结合[Ca2+]cyt结果说明CbFAD3-过表达植物中PM Ca2+-ATPase的持续激活改变了早期胁迫时诱导的Ca2+信号传递。
Mean net K+ fluxmeasured from the biofilms in response to treatment with 5 mMand 10mM TEA
英文摘要
Bacteria in biofilms are able to utilize potassium ion channel mediated electrical signaling to achieve cell–cell communication. However, it remains unclear whether these signals play a role in Geobacter sp.when surrounded by an intense electric field.
This study used a potassium channel blocker (tetraethylammonium, TEA) that interfered with the release of K+ but not bacterial growth to demonstrate that potassium ion channel-mediated electrical signaling affected the formation and electroactivity of Geobacter sulfurreducens. The results showed that 5 mM TEA slowed the formation of Geobacter sulfurreducens biofilm, and the current density was ~50% lower than in the control.
The electrochemical analyses showed that the electroactivity of the biofilms with TEA addition was inferior. In particular, the micrometer- scale biofilm with TEA exhibited fewer high current peaks, and the species of outermost groups that participated in the electron transfer in Geobacter sulfurreducens biofilms was different from the control.
This work provides initial evidence to reveal the role of potassium channels in Geobacter sulfurreducens electroactive biofilms.
The dual-affinity nitrate transceptor NITRATE TRANSPORTER 1.1 (NRT1.1) has two modes of transport and signaling, governed by threonine101 (T101) phosphorylation. NRT1.1 regulates lateral root (LR) development by modulating nitrate-dependent basipetal auxin export and nitrate-mediated signal transduction.
Here, using the Arabidopsis thaliana NRT1.1T101D phosphomimetic and NRT1.1T101A non-phosphorylatable mutants, we found that the phosphorylation state of NRT1.1 plays a key role in NRT1.1 function during LR development. Single-particle tracking revealed that phosphorylation affected NRT1.1 spatiotemporal dynamics. The phosphomimetic NRT1.1T101D form showed fast lateral mobility and membrane partitioning that facilitated auxin flux under low-nitrate conditions.
By contrast, non-phosphorylatable NRT1.1T101A showed low lateral mobility and oligomerized at the plasma membrane (PM), where it induced endocytosis via the clathrin-mediated endocytosis and microdomain-mediated endocytosis pathways under high-nitrate conditions.
These behaviors promoted LR development by suppressing NRT1.1-controlled auxin transport on the PM and stimulating Ca2+-ARABIDOPSIS NITRATE REGULATED 1 (ANR1) signaling from the endosome.
2014年12月24日,湖南大学曾光明、陈桂秋、谭琼用NMT在Chemosphere上发表了标题为Physiological fluxes and antioxidative enzymes activities of immobilized Phanerochaete chrysosporium loaded with TiO2 nanoparticles after exposure to toxic pollutants in solution的研究成果。
期刊:Chemosphere
主题:TiO2提升黄孢原毛平革菌镉耐受力的生理证据
标题:Physiological fluxes and antioxidative enzymes activities of immobilized Phanerochaete chrysosporium loaded with TiO2 nanoparticles after exposure to toxic pollutants in solution
影响因子:4.208
检测指标:H+、O2、Cd2+流速
作者:湖南大学曾光明、陈桂秋、谭琼
英文摘要
Immobilized Phanerochaete chrysosporium loaded with TiO2 nanoparticles (PTNs) are novel high-value bioremediation materials for adsorbing cadmium and for degrading 2,4-dichlorophenol (2,4-DCP). The real-time changes in H+ and O2 fluxes were measured using the noninvasive microtest technique (NMT).
The H+ influx increased after the addition of 2,4-DCP, and shifted to efflux following the addition of Cd2+. The O2 flux decreased after the addition of both 2,4-DCP and Cd2+. A larger Cd2+ flux was immediately observed after exposure to 0.5 mM Cd2+ (−351.25 pmol cm−2 s−1) than to 0.1 mM Cd2+ (−107.47 pmol cm−2 s−1). The removal of Cd2+ by the PTNs increased more after treatment with the 0.5 mM exposure solution (27.6 mg g−1) than with the 0.1 mM exposure solution (3.49 mg g−1).
The enzyme activities were analyzed to review the antioxidative defense system of PTNs in a solution containing various concentrations of Cd2+. The activities of the coenzyme nicotinamide adenine dinucleotide (NADH) oxidase as well as the enzyme catalase (CAT) plateaued at 6.5 U g−1 FW and 9.7 U g−1 FW, respectively, after exposure to 0.25 mM Cd2+. The activity of superoxide dismutase (SOD) increased gradually in solutions containing 0.1–0.6 mM Cd2+, and eventually reached a maximum (68.86 U g−1 FW).
These results illustrate how the antioxidative defense system and the physiological fluxes of PTNs respond to the stress caused by toxic pollutants.
加入2,4-DCP后,H+流入量增加,而加入Cd2+后,H+流入量移出。同时添加2,4-DCP和Cd2+后,O2通量下降。暴露于0.5 mM Cd2+(-351.25 pmol cm-2 s-1)后立即观察到更大的Cd2+通量,而不是暴露于0.1 mM Cd2+(-107.47 pmol cm-2 2 s-1)。用0.5 mM暴露溶液(27.6 mg g-1)处理后,PTN去除Cd2+的增加比使用0.1 mM暴露溶液(3.49 mg g-1)处理的增加更多。
分析了酶的活性,以审查包含各种浓度的Cd2+的溶液中PTN的抗氧化防御系统。暴露于0.25 mM Cd2+后,辅酶烟酰胺腺嘌呤二核苷酸(NADH)氧化酶和过氧化氢酶(CAT)的活性分别稳定在6.5 U g-1 FW和9.7 U g-1 FW上。超氧化物歧化酶(SOD)的活性在含0.1–0.6 mM Cd2+的溶液中逐渐增加,并最终达到最大值(68.86 U g-1 FW)。
这些结果说明了PTN的抗氧化防御系统和生理通量如何响应有毒污染物引起的压力。
Fig. 2. (A) Real-time Cd2+ flux of PTNs exposed to 0.1 mM Cd(NO3)2 and 10 mg L
The mean flux of Ca2+ under different pCO2 I scenarios. Mean ± s.d. values per experimental assay are given (n = 3). Upper, Ca2+ efflux under positive phototaxis. Lower, Ca2+ influx under negative phototaxis. ‘−’ on the vertical scale means Ca2+ entry. LC4, flagellar outer dynein arm light chain 4; DC3, outer dynein arm docking complex protein 3; IC138, arm dynein; RSP, radial spoke protein; PF20, a protein of the central pair apparatus; PKA, cAMP-dependent protein kinase; PP2A, protein phosphatase 2A; CK1, casein kinase DIP13/NA14, deflagellation inducible protein; DNAAF3/PF22, axonemal dynein assembly factor. Mean ± s.d. values per experimental assay are given (n = 3). Different letters (a–c) in panel indicate significant differences (P < 0.05) among treatments.
英文摘要
Motility plays a critical role in algal survival and reproduction, with implications for aquatic ecosystem stability. However, the effect of elevated CO2 on marine, brackish and freshwater algal motility is unclear.
Here we show, using laboratory microscale and field mesoscale experiments, that three typical phytoplankton species had decreased motility with increased CO2. Polar marine Microglena sp., euryhaline Dunaliella salina and freshwater Chlamydomonas reinhardtii were grown under different CO2 concentrations for 5 years. Long-term acclimated Microglena sp. showed substantially decreased photo-responses in all treatments, with a photophobic reaction affecting intracellular calcium concentration.
Genes regulating flagellar movement were significantly downregulated (P < 0.05), alongside a significant increase in gene expression for flagellar shedding (P < 0.05). D. salina and C. reinhardtii showed similar results, suggesting that motility changes are common across flagellated species.
As the flagella structure and bending mechanism are conserved from unicellular organisms to vertebrates, these results suggest that increasing surface water CO2 concentrations may affect flagellated cells from algae to fish.
2014年01月14日,中科院水生所王强、陈辉用NMT在Plant and Cell Physiology上发表了标题为Ca2+ Signal Transduction Related to Neutral Lipid Synthesis in an Oil-Producing Green Alga Chlorella sp. C2的研究成果。
期刊:Plant and Cell Physiology
主题:Ca2+流指示的微藻氮胁迫信号转导研究
标题:Ca2+ Signal Transduction Related to Neutral Lipid Synthesis in an Oil-Producing Green Alga Chlorella sp. C2
影响因子:4.134
检测指标:Ca2+流速
作者:中科院水生所王强、陈辉
英文摘要
Changes in the cytosolic Ca2+ levels and the role of Ca2+ signal transduction in neutral lipid synthesis in Chlorella sp. C2 under nitrogen starvation conditions were investigated. The results detected by using the scanning ion-selective electrode technique demonstrate that nitrogen starvation induced significant Ca2+ influx across the plasma membrane into cells.
Ca2+ fluorescence imaging and flow cytometry were used to estimate the effect of this Ca2+ influx on the generation of the Ca2+ signal, and the results showed that the cytosolic Ca2+ concentration increased transiently and then remained at a stable, high level when the cells were exposed to nitrogen starvation. However, the increase could be inhibited by pre-treatment with the Ca2+ channel blockers ruthenium red, verapamil and GdCl3, indicating that both the influx of Ca2+ from the extracellular space via Ca2+ channels that are localized in the plasma membrane and the release of Ca2+ from intracellular calcium storage via the internal calcium store were required for the generation and transduction of the Ca2+ signal.
During nitrogen starvation, neutral lipid synthesis in Chlorella sp. C2 in response to stress conditions was also inhibited to differing degrees by pre-treatment with the three Ca2+ channel blockers, demonstrating the regulation of Ca2+ via these Ca2+ channels in neutral lipid synthesis.
The results suggested that by transduction of extracellular stress signals into the cell and the regulation of the Ca2+ signal in neutral lipid synthesis, Ca2+ signal transduction played important roles in the response mechanism of Chlorella sp. C2 to nitrogen starvation.
Fig. 1 The total Ca2+ flux rates over 5 min in Chlorella sp. C2 under N starvation. (a) Microphotographic examples of Ca2+ ion flux/voltage-clamp measurements. (b) Total flux rates of Ca2+ were detected at 0, 0.5, 2 and 8 d after N starvation. The columns represent the means of three replicated studies in each sample, with the SD of the means (t-test, P < 0.05). The significance of the differences between the control (0 d) and other test values was tested using a one-way analysis of variance. *P < 0.05 vs. control.
Figure 3 Changes in net flux of Cd of periphyton over times (a) and the mean net influx of periphyton (b) under different treatments. Cd0+P, Cd5+P, and Cd50+P represent the periphyton treatment of Cd added at soil Cd content of 0 mg Kg-1, 5 mg Kg-1, and 50 mg Kg-1 respectively. Different letters within same column indicate significant difference among different treatments at P < 0.05, while same letters represent no significant difference.
英文摘要
Periphyton plays a significant role in heavy metal transfer in wetlands, but its contribution to cadmium (Cd) bioavailability in paddy fields remains largely unexplored.
The main aim of this study was to investigate the effect of periphyton on Cd behavior in paddy fields. Periphyton significantly decreased Cd concentrations in paddy waters.
Non-invasive micro-test technology analyses indicated that periphyton can absorb Cd from water with a maximum Cd2+ influx rate of 394 pmol cm−2 s−1 and periphyton intrusion significantly increased soil Cd concentrations.
However, soil Cd bioavailability declined significantly due to soil pH increase and soil redox potential (Eh) decrease induced by periphyton. With periphyton, more Cd was adsorbed and immobilized on organic matter, carbonates, and iron and manganese oxides in soil. Consequently, Cd content in rice decreased significantly.
These findings give insights into Cd biogeochemistry in paddy fields with periphyton, and may provide a novel strategy for reducing Cd accumulation in rice.
Indole derivatives derived from the secondary metabolites of marine organisms possess the excellent antifouling property to inhibit the biofouling. These compounds and their analogues are simple in structure and have been proven to have low toxicity and bioaccumulation. Therefore, the active indole antifoulants are expected to replace the potentially toxic antifoulants which are widely used in current antifouling coatings.
Seven indole derivatives were synthesized via the Friedel-Crafts alkylation reaction and were characterized by IR spectra, 1H NMR, 13C NMR and elemental analysis. Inhibition experiments against marine algae and bacteria were conducted, and the partial inhibition rates of algae and bacteria were more than 90%. This outcome indicates that indole derivatives possess excellent properties suitable for use as targeting anti-fouling compound for algae and bacteria. Non-invasive Micro-test Technology (NMT) reveals that the Ca2+ efflux of Platymonas subcordiformis dramatically increased in the presence of indole derivatives, which is inferred to be the molecular mechanism for inhibiting the growth of marine algae.
The antifouling coatings containing indole derivatives were prepared and subjected to an antifouling test in a marine environment, and the results show that N-(1-H-5-bromo-indole-3-ylmethyl) benzamide and N-(1-H-2-phenyl-indole-3-ylmethyl) benzamide possess better antifouling performance compared to copper pyrithione (CuPT). According to these results, indole derivatives in this study might become novel and promising antifoulants.
The interactions between metal and phytoplankton are affected by salinity in estuarine environments. While water chemistry is an important factor regulating the metal bioavailability in phytoplankton, the physiological adaptation of the algae cells may also change their intrinsic response to metals.
In this work, we tried to interpret the salinity-dependent Cd toxicity in a pennate diatom Nitzchia closterium from a biological side. As with many studies, we observed Cd toxicity to the diatom increased with decreasing salinity. However, changing free Cd ion concentrations may be partly responsible for the enhanced Cd toxicity.
Multiple evidences showed that diatom cells acclimated at low salinity had stronger intrinsic Cd adsorption capacity. Salinity significantly affected not only the nanostructures but also the biochemical composition in the cell surface of the diatom. Diatom cells grown at lower salinity had a lower surface potential, higher specific surface area, and more sulfur-containing groups in the cell wall, leading to stronger Cd binding capacity in the cells. Meanwhile, more Si was present as poly-silicic acid when the salinity decreased. The change of Si content and speciation in the cell wall are also considered a major reason for the variations of Cd surface binding.
Our study provided new clues for the salinity-dependent metal toxicity in marine diatoms.
Fig. 3. Cd2+ fluxes around the cell surface of the diatom P. tricornutum in the testing medium containing 8.9 μM Cd2+. (A) Instant net Cd2+ fluxes measured by a non-invasive microelectrode probe; (B) mean Cd2+ fluxes for the L-, M-, and H-Si cells. Means do not significantly differ (p>0.05) if they bear the same letter (n = 6). L, low; M, mid; H, high.
英文摘要
Marine phytoplankton possess a sophisticated homeostatic network to counteract metal toxicity. Changes in environmental conditions such as ambient nutrient concentrations can significantly impact their intrinsic metal sensitivity. In this study, we evaluated the role of silicon (Si) in counteracting cadmium (Cd) toxicity in the marine diatom Phaeodactylum tricornutum. We first demonstrated that Si enrichment dramatically enhanced Cd tolerance and changed the Cd accumulation in the diatom.
Our modeling suggested that Si-enriched cells adsorbed more Cd but had a higher Cd elimination rate than the Si-starved cells. Examinations by atomic force microscopy and X-ray photoelectron spectroscopy revealed that the Si-enriched cells had better silification andmore SiO- in the cell walls, which markedly lowered the surface potential of the diatom cells and allowed them to attract more Cd.
Although the Si-enriched cells tended to have a high Cd burden when facing Cd stress, they suppressed the increase of intracellular Cd by both down-regulating the influx transporter ZIP and up-regulating the efflux transporter ATPase5-1B.
Our study shows the significant roles Si plays in maintaining metal homeostasisand combating Cd challenge in marine diatoms.
为了研究菌丝尖端线粒体的呼吸活性,就需要一种高空间分辨率的氧流速测定方法。加拿大研究人员Roger R. Lew以粗糙脉孢菌(Neurospora crassa)为实验材料,运用非损伤微测技术结合显微技术研究了氰化物等处理后菌丝表面不同区域的氧流速变化。发现菌丝表面的氧内流(吸收)速率可被氰化物抑制,而交替氧化酶则可以恢复呼吸作用。菌丝尖端靠后10μm有个氧内流速率很大的区域,且氧内流的速率与菌丝的生长速率相关,而线粒体在菌丝体上富集的区域在距离尖端5~10μm处,与最大氧内流区域不同。因此,菌丝尖端的线粒体在生长发育的呼吸需求中所起的作用较小。
This study investigated the influences of cetyltrimethyl trimethyl ammonium chloride (CTAC), an emerging pollutant quaternary ammonium compound (QAC) in municipal effluents, on the transfer and uptake of NH4+ by Chlorella vulgaris F1068 cells removed EPS artificially (EPS-R) and coated EPS naturally (EPS-C) under different scenarios (e.g., the presence or absence of CTAC, different photoperiod sequences (light 12 h: dark 12 h or dark 12 h: light 12 h)).
The results showed that the removal of EPS increased the transfer and uptake of NH4+ but the presence of EPS caged NH4+ and effectively weakened the stress of CTAC (<0.5 mg/L) on NH4+ uptake. The main mechanism was considered that CTAC in the concentration range from 0.1 to 0.5 mg/L induced an increased amount of polysaccharide and protein in EPS and thus protected algal normal physiological functions (including cell membrane permeability and glutamine synthetase activity) from the damage of CTAC (0.1 to 0.5 mg/L) regardless of the photoperiod sequences.
Thereby, the findings of this study provided an insight into the role of algal EPS in transfer and uptake of nutrients under the coexisted toxics for the future algae-based sewage treatment application.
结果表明:在没有CTAC的6小时光照下,EPS-C细胞或EPS-R细胞的NH4+通量分别达到-1.87ng /(cm2·s)和-2.63ng /(cm2·s)。当添加0.5 mg / L的CTAC时,EPS-C或EPS-R细胞的NH4+通量急剧下降至-0.94 ng /(cm2·s)和-0.73 ng /(cm2·s)。相反,当EPS-R细胞和EPS-C细胞在黑暗中培养6小时无论CTAC存在与否,EPS-C细胞和EPS-R细胞的NH4+流速从负值转换为正值,表明NH4+从细胞内环境流出到培养基。
非损伤微测技术在水旱胁迫上的应用,主要集中在干旱胁迫下的根系发育、气孔调节、活性氧运输。还包括干旱胁迫下养分元素的吸收。涉及到的研究团队有福建农林大学许卫锋教授团队、浙江大学张国平教授团队、安徽农业大学宛晓春教授团队、西北农林科技大学李积胜教授团队、长江大学吴强盛团队等。其中,2018年,中科院西北生态环境资源研究所石玉兰博士在Journal of Experimental Botany发表的Integrated regulation triggered by a cryophyte ω-3 desaturase gene confers multiple-stress tolerance in tobacco成果中,利用非损伤微测技术检测了盐胁迫、渗透胁迫下,烟草根的Ca2+跨膜转运信号,为该研究提供了关键数据证据。
2014年12月24日,湖南大学曾光明、陈桂秋、谭琼用NMT在Chemosphere上发表了标题为Physiological fluxes and antioxidative enzymes activities of immobilized Phanerochaete chrysosporium loaded with TiO2 nanoparticles after exposure to toxic pollutants in solution的研究成果。
期刊:Chemosphere
主题:TiO2提升黄孢原毛平革菌镉耐受力的生理证据
标题:Physiological fluxes and antioxidative enzymes activities of immobilized Phanerochaete chrysosporium loaded with TiO2 nanoparticles after exposure to toxic pollutants in solution
影响因子:4.208
检测指标:H+、O2、Cd2+流速
作者:湖南大学曾光明、陈桂秋、谭琼
英文摘要
Immobilized Phanerochaete chrysosporium loaded with TiO2 nanoparticles (PTNs) are novel high-value bioremediation materials for adsorbing cadmium and for degrading 2,4-dichlorophenol (2,4-DCP). The real-time changes in H+ and O2 fluxes were measured using the noninvasive microtest technique (NMT).
The H+ influx increased after the addition of 2,4-DCP, and shifted to efflux following the addition of Cd2+. The O2 flux decreased after the addition of both 2,4-DCP and Cd2+. A larger Cd2+ flux was immediately observed after exposure to 0.5 mM Cd2+ (−351.25 pmol cm−2 s−1) than to 0.1 mM Cd2+ (−107.47 pmol cm−2 s−1). The removal of Cd2+ by the PTNs increased more after treatment with the 0.5 mM exposure solution (27.6 mg g−1) than with the 0.1 mM exposure solution (3.49 mg g−1).
The enzyme activities were analyzed to review the antioxidative defense system of PTNs in a solution containing various concentrations of Cd2+. The activities of the coenzyme nicotinamide adenine dinucleotide (NADH) oxidase as well as the enzyme catalase (CAT) plateaued at 6.5 U g−1 FW and 9.7 U g−1 FW, respectively, after exposure to 0.25 mM Cd2+. The activity of superoxide dismutase (SOD) increased gradually in solutions containing 0.1–0.6 mM Cd2+, and eventually reached a maximum (68.86 U g−1 FW).
These results illustrate how the antioxidative defense system and the physiological fluxes of PTNs respond to the stress caused by toxic pollutants.
加入2,4-DCP后,H+流入量增加,而加入Cd2+后,H+流入量移出。同时添加2,4-DCP和Cd2+后,O2通量下降。暴露于0.5 mM Cd2+(-351.25 pmol cm-2 s-1)后立即观察到更大的Cd2+通量,而不是暴露于0.1 mM Cd2+(-107.47 pmol cm-2 2 s-1)。用0.5 mM暴露溶液(27.6 mg g-1)处理后,PTN去除Cd2+的增加比使用0.1 mM暴露溶液(3.49 mg g-1)处理的增加更多。
分析了酶的活性,以审查包含各种浓度的Cd2+的溶液中PTN的抗氧化防御系统。暴露于0.25 mM Cd2+后,辅酶烟酰胺腺嘌呤二核苷酸(NADH)氧化酶和过氧化氢酶(CAT)的活性分别稳定在6.5 U g-1 FW和9.7 U g-1 FW上。超氧化物歧化酶(SOD)的活性在含0.1–0.6 mM Cd2+的溶液中逐渐增加,并最终达到最大值(68.86 U g-1 FW)。
这些结果说明了PTN的抗氧化防御系统和生理通量如何响应有毒污染物引起的压力。
Fig. 2. (A) Real-time Cd2+ flux of PTNs exposed to 0.1 mM Cd(NO3)2 and 10 mg L
作者: xuyuenmt 更新时间:2022-07-06 11:15
Environ Pollut:NMT验证稻田生物膜大量吸附Cd降低水稻Cd积累 | NMT重金属创新科研平台
研究使用平台:NMT重金属创新科研平台
期刊:Environmental Pollution
主题:NMT验证稻田生物膜大量吸附Cd降低水稻Cd积累
标题:Paddy periphyton reduced cadmium accumulation in rice (Oryza sativa) by removing and immobilizing cadmium from the water–soil interface
Figure 3 Changes in net flux of Cd of periphyton over times (a) and the mean net influx of periphyton (b) under different treatments. Cd0+P, Cd5+P, and Cd50+P represent the periphyton treatment of Cd added at soil Cd content of 0 mg Kg-1, 5 mg Kg-1, and 50 mg Kg-1 respectively. Different letters within same column indicate significant difference among different treatments at P < 0.05, while same letters represent no significant difference.
英文摘要
Periphyton plays a significant role in heavy metal transfer in wetlands, but its contribution to cadmium (Cd) bioavailability in paddy fields remains largely unexplored.
The main aim of this study was to investigate the effect of periphyton on Cd behavior in paddy fields. Periphyton significantly decreased Cd concentrations in paddy waters.
Non-invasive micro-test technology analyses indicated that periphyton can absorb Cd from water with a maximum Cd2+ influx rate of 394 pmol cm−2 s−1 and periphyton intrusion significantly increased soil Cd concentrations.
However, soil Cd bioavailability declined significantly due to soil pH increase and soil redox potential (Eh) decrease induced by periphyton. With periphyton, more Cd was adsorbed and immobilized on organic matter, carbonates, and iron and manganese oxides in soil. Consequently, Cd content in rice decreased significantly.
These findings give insights into Cd biogeochemistry in paddy fields with periphyton, and may provide a novel strategy for reducing Cd accumulation in rice.
The interactions between metal and phytoplankton are affected by salinity in estuarine environments. While water chemistry is an important factor regulating the metal bioavailability in phytoplankton, the physiological adaptation of the algae cells may also change their intrinsic response to metals.
In this work, we tried to interpret the salinity-dependent Cd toxicity in a pennate diatom Nitzchia closterium from a biological side. As with many studies, we observed Cd toxicity to the diatom increased with decreasing salinity. However, changing free Cd ion concentrations may be partly responsible for the enhanced Cd toxicity.
Multiple evidences showed that diatom cells acclimated at low salinity had stronger intrinsic Cd adsorption capacity. Salinity significantly affected not only the nanostructures but also the biochemical composition in the cell surface of the diatom. Diatom cells grown at lower salinity had a lower surface potential, higher specific surface area, and more sulfur-containing groups in the cell wall, leading to stronger Cd binding capacity in the cells. Meanwhile, more Si was present as poly-silicic acid when the salinity decreased. The change of Si content and speciation in the cell wall are also considered a major reason for the variations of Cd surface binding.
Our study provided new clues for the salinity-dependent metal toxicity in marine diatoms.
Fig. 3. Cd2+ fluxes around the cell surface of the diatom P. tricornutum in the testing medium containing 8.9 μM Cd2+. (A) Instant net Cd2+ fluxes measured by a non-invasive microelectrode probe; (B) mean Cd2+ fluxes for the L-, M-, and H-Si cells. Means do not significantly differ (p>0.05) if they bear the same letter (n = 6). L, low; M, mid; H, high.
英文摘要
Marine phytoplankton possess a sophisticated homeostatic network to counteract metal toxicity. Changes in environmental conditions such as ambient nutrient concentrations can significantly impact their intrinsic metal sensitivity. In this study, we evaluated the role of silicon (Si) in counteracting cadmium (Cd) toxicity in the marine diatom Phaeodactylum tricornutum. We first demonstrated that Si enrichment dramatically enhanced Cd tolerance and changed the Cd accumulation in the diatom.
Our modeling suggested that Si-enriched cells adsorbed more Cd but had a higher Cd elimination rate than the Si-starved cells. Examinations by atomic force microscopy and X-ray photoelectron spectroscopy revealed that the Si-enriched cells had better silification andmore SiO- in the cell walls, which markedly lowered the surface potential of the diatom cells and allowed them to attract more Cd.
Although the Si-enriched cells tended to have a high Cd burden when facing Cd stress, they suppressed the increase of intracellular Cd by both down-regulating the influx transporter ZIP and up-regulating the efflux transporter ATPase5-1B.
Our study shows the significant roles Si plays in maintaining metal homeostasisand combating Cd challenge in marine diatoms.
抑制HvNAT2降低了大麦对镉的耐受性。随后,研究使用两个RNAi株系(HvNAT2-RNAi1和HvNAT2-RNAi2)检测了HvNAT2的功能;与对照组相比,HvNAT2-RNAi1和HvNAT2-RNAi2中HvNAT2表达的降低导致Cd敏感表型;15 d Cd处理后,HvNAT2-RNAi系的茎干重平均降低了40.1%和55.3%,而GP的干重分别为22.0%和28.9%;HvNAT2 RNAi株系的根系Cd浓度和植株Cd积累均显著降低,但其根部向地上部的Cd转运率显著高于GP。
标题:TaWRKY70 positively regulates TaCAT5 enhanced Cd tolerance in transgenic Arabidopsis
作者:贵州大学任明见、贵州师范大学杜旭烨、Zhenzhen Jia、李木子
检测离子/分子指标Cd2+检测样品
拟南芥根分生区
中文摘要
WRKY转录因子(TFs)参与了植物对多种生物和非生物胁迫的响应;然而,WRKY TFs在小麦响应Cd胁迫中的调控作用仍然未知。本文研究了小麦TaWRKY70 TF在Cd胁迫下的机制。在拟南芥中表达TaWRKY70来进行功能分析。TaWRKY70通过Cd在根中积累而不是在叶片中积累来调节Cd耐受性。表达TaWRKY70后,拟南芥根系的Cd2+内流速率减少。定量实时荧光定量PCR(qRT-PCR)结果显示,Cd胁迫下,heavy metal ATPase (AtHMA3)、natural resistance-associatedmacrophage protein (AtNRAMP5)、 yellow stripe1-like (AtYSL3)、和iron transport protein (AtIRT1)的表达水平降低。转基因拟南芥的电解质渗漏率、丙二醛和过氧化氢含量均低于野生型,而抗氧化酶活性则高于野生型。电泳迁移率变化实验(EMSA)、酵母单杂实验(Y1H)和瞬时反式激活实验证明TaWRKY70可以直接结合到TaCAT5启动子上。本研究的发现为WRKY TFs参与重金属胁迫响应的提供了新的理解。
研究使用非损伤微测技术(NMT)测试了植物生长初期根尖中的Cd2+流速。BADH转基因株系中Cd2+的内流少于未经Cd处理的WT株系。0.5 mM CdCl2处理后,WT株系Cd2+外排,平均值为131.81 pmol cm-2s-1,BADH转基因株系Cd2+外排增强,平均值为188.60 pmol cm-2s-1(图1A, B)。结果表明,转基因植株比野生型植株具有更大的净Cd2+流速范围。为了研究Cd对其他离子流速的影响,研究检测了有无0.5 mM Cd处理下的烟草植物中净H+和K+流速的变化。在无Cd处理下,转基因植株和WT株系的净H+流速差异不大。然而,在0.5 mM CdCl2处理下,H+内流显著增加,且这种增加在转基因植株中更为明显(图1C, D)。在Cd胁迫下,BADH转基因株系和WT株系的K+流速曲线有明显的差异,K+的平均流速由内流变为外排,且WT株系中Cd胁迫诱导的K+外排速率大于转基因株系(图1E, F)。这些结果表明GB在Cd诱导下减少了K+外排,增强了Cd胁迫下烟草根部的H+内流。
标题:Comparative transcriptome combined with biochemical and physiological analyses provide new insights toward cadmium accumulation with two contrasting Nicotiana species
标题:Nitric Oxide Enhances Cytotoxicity of Lead by Modulating the Generation of Reactive Oxygen Species and Is Involved in the Regulation of Pb2+ and Ca2+ Fluxes in Tobacco BY-2 Cells
对照组:0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, pH 6.0 Cd处理组:0.1 mM KCl, 0.1 mM CaCl2, 0.1 mM MgCl2, 0.5 mM NaCl, 0.3 mM MES, 0.2 mM Na2SO4, 0.05 mM CdCl2, pH 6.0
标题:Hemin-decreased cadmium uptake in pak choi (Brassica chinensis L.)seedlings is heme oxygenase-1 dependent and relies on its by-products ferrous iron and carbon monoxide
标题:Exogenous melatoninalleviates cadmium uptake and toxicity in apple rootstocks
作者:沈阳农业大学吕德国、何佳丽
检测离子/分子指标
Cd2+
检测样品
距根尖顶端300μm、600μm、1200μm、1500μm和3000μm的根表上的点
中文摘要(谷歌机翻)
为了检查褪黑素在苹果属植物中对Cd吸收,积累和排毒的潜在作用,我们将两种在Cd吸收和积累方面差异很大的苹果砧木暴露于0或30μMCd和0或100μM褪黑素。与耐镉的微小苹果花青霉菌“青州林琴”相比,耐镉的baccata对镉胁迫的内源性褪黑激素产生的刺激程度更大。褪黑素的应用减弱了镉诱导的生长,光合作用和酶活性以及ROS和MDA积累的减少。褪黑素处理比镉胁迫的巴塔卡巴氏菌更有效地恢复了镉对微苹果念珠菌青州林琴的光合作用,光合色素和生物量的恢复。外源性褪黑素降低了根部对镉的2+吸收,降低了叶片的镉含量两种暴露于镉的砧木中的镉积累,降低的镉转运因子(T f s)s和增加的根,茎和叶褪黑素含量s。褪黑素的应用增加了抗氧化剂的浓度和酶的活性,以清除Cd诱导的ROS。外源性褪黑素处理改变了调节Cd吸收,转运和排毒的几种基因的mRNA水平,包括HA7,NRAMP1,NRAMP3 HMA4,PCR2,NAS1,MT2, ABCC1和MHX。综上所述,这些结果表明,外源褪黑素减少了苹果属植物中的空中部分Cd积累并减轻了Cd毒性,这可能是由于褪黑激素介导的Cd在组织中的分配以及抗氧化防御系统的诱导以及转录过程中涉及排毒的关键基因的诱导。
The mean flux of Ca2+ under different pCO2 I scenarios. Mean ± s.d. values per experimental assay are given (n = 3). Upper, Ca2+ efflux under positive phototaxis. Lower, Ca2+ influx under negative phototaxis. ‘−’ on the vertical scale means Ca2+ entry. LC4, flagellar outer dynein arm light chain 4; DC3, outer dynein arm docking complex protein 3; IC138, arm dynein; RSP, radial spoke protein; PF20, a protein of the central pair apparatus; PKA, cAMP-dependent protein kinase; PP2A, protein phosphatase 2A; CK1, casein kinase DIP13/NA14, deflagellation inducible protein; DNAAF3/PF22, axonemal dynein assembly factor. Mean ± s.d. values per experimental assay are given (n = 3). Different letters (a–c) in panel indicate significant differences (P < 0.05) among treatments.
英文摘要
Motility plays a critical role in algal survival and reproduction, with implications for aquatic ecosystem stability. However, the effect of elevated CO2 on marine, brackish and freshwater algal motility is unclear.
Here we show, using laboratory microscale and field mesoscale experiments, that three typical phytoplankton species had decreased motility with increased CO2. Polar marine Microglena sp., euryhaline Dunaliella salina and freshwater Chlamydomonas reinhardtii were grown under different CO2 concentrations for 5 years. Long-term acclimated Microglena sp. showed substantially decreased photo-responses in all treatments, with a photophobic reaction affecting intracellular calcium concentration.
Genes regulating flagellar movement were significantly downregulated (P < 0.05), alongside a significant increase in gene expression for flagellar shedding (P < 0.05). D. salina and C. reinhardtii showed similar results, suggesting that motility changes are common across flagellated species.
As the flagella structure and bending mechanism are conserved from unicellular organisms to vertebrates, these results suggest that increasing surface water CO2 concentrations may affect flagellated cells from algae to fish.
Indole derivatives derived from the secondary metabolites of marine organisms possess the excellent antifouling property to inhibit the biofouling. These compounds and their analogues are simple in structure and have been proven to have low toxicity and bioaccumulation. Therefore, the active indole antifoulants are expected to replace the potentially toxic antifoulants which are widely used in current antifouling coatings.
Seven indole derivatives were synthesized via the Friedel-Crafts alkylation reaction and were characterized by IR spectra, 1H NMR, 13C NMR and elemental analysis. Inhibition experiments against marine algae and bacteria were conducted, and the partial inhibition rates of algae and bacteria were more than 90%. This outcome indicates that indole derivatives possess excellent properties suitable for use as targeting anti-fouling compound for algae and bacteria. Non-invasive Micro-test Technology (NMT) reveals that the Ca2+ efflux of Platymonas subcordiformis dramatically increased in the presence of indole derivatives, which is inferred to be the molecular mechanism for inhibiting the growth of marine algae.
The antifouling coatings containing indole derivatives were prepared and subjected to an antifouling test in a marine environment, and the results show that N-(1-H-5-bromo-indole-3-ylmethyl) benzamide and N-(1-H-2-phenyl-indole-3-ylmethyl) benzamide possess better antifouling performance compared to copper pyrithione (CuPT). According to these results, indole derivatives in this study might become novel and promising antifoulants.
The interactions between metal and phytoplankton are affected by salinity in estuarine environments. While water chemistry is an important factor regulating the metal bioavailability in phytoplankton, the physiological adaptation of the algae cells may also change their intrinsic response to metals.
In this work, we tried to interpret the salinity-dependent Cd toxicity in a pennate diatom Nitzchia closterium from a biological side. As with many studies, we observed Cd toxicity to the diatom increased with decreasing salinity. However, changing free Cd ion concentrations may be partly responsible for the enhanced Cd toxicity.
Multiple evidences showed that diatom cells acclimated at low salinity had stronger intrinsic Cd adsorption capacity. Salinity significantly affected not only the nanostructures but also the biochemical composition in the cell surface of the diatom. Diatom cells grown at lower salinity had a lower surface potential, higher specific surface area, and more sulfur-containing groups in the cell wall, leading to stronger Cd binding capacity in the cells. Meanwhile, more Si was present as poly-silicic acid when the salinity decreased. The change of Si content and speciation in the cell wall are also considered a major reason for the variations of Cd surface binding.
Our study provided new clues for the salinity-dependent metal toxicity in marine diatoms.
Fig. 3. Cd2+ fluxes around the cell surface of the diatom P. tricornutum in the testing medium containing 8.9 μM Cd2+. (A) Instant net Cd2+ fluxes measured by a non-invasive microelectrode probe; (B) mean Cd2+ fluxes for the L-, M-, and H-Si cells. Means do not significantly differ (p>0.05) if they bear the same letter (n = 6). L, low; M, mid; H, high.
英文摘要
Marine phytoplankton possess a sophisticated homeostatic network to counteract metal toxicity. Changes in environmental conditions such as ambient nutrient concentrations can significantly impact their intrinsic metal sensitivity. In this study, we evaluated the role of silicon (Si) in counteracting cadmium (Cd) toxicity in the marine diatom Phaeodactylum tricornutum. We first demonstrated that Si enrichment dramatically enhanced Cd tolerance and changed the Cd accumulation in the diatom.
Our modeling suggested that Si-enriched cells adsorbed more Cd but had a higher Cd elimination rate than the Si-starved cells. Examinations by atomic force microscopy and X-ray photoelectron spectroscopy revealed that the Si-enriched cells had better silification andmore SiO- in the cell walls, which markedly lowered the surface potential of the diatom cells and allowed them to attract more Cd.
Although the Si-enriched cells tended to have a high Cd burden when facing Cd stress, they suppressed the increase of intracellular Cd by both down-regulating the influx transporter ZIP and up-regulating the efflux transporter ATPase5-1B.
Our study shows the significant roles Si plays in maintaining metal homeostasisand combating Cd challenge in marine diatoms.