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
• 影响因子：4.298
• 检测指标：Na+，K+，H+流速
• 检测部位：甘草根（距离根尖200、500、700、1000、1300、1700、2000、2300、2700μm）
• Na+，K+，H+流实验处理方法：

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.

 

中文摘要（谷歌机翻）

我们在短期NaCl胁迫（100 mM，24 h）期间研究了盐敏感信号分子对多年生草本植物甘草（Glycyrrhiza uralensis）中离子通量和与K+ /Na+稳态相关的基因表达的影响。盐处理导致根细胞中Na+积累比叶细胞更明显。 Na+离子主要在液泡中分隔。暴露于NaCl的根表现出细胞外ATP（eATP），细胞溶质Ca2+，H2O2和NO水平的增加。

稳态通量记录显示，由于质膜（PM）中激活的Na+/H+反向运输系统，这些盐敏感信号分子增强了NaCl响应性Na+流出。此外，由去极化激活的阳离子通道介导的盐诱导的K+流出通过添加Ca2+，H2O2，NO和eATP而降低。这些分子的盐适应性作用（Na+挤压和K+维持）通过药理学试剂减少，包括LaCl3（PMCa2+通道抑制剂），DMTU（活性氧清除剂），cPTIO（NO清除剂）或PPADS（动物PM嘌呤P2受体的拮抗剂。

RT-qPCR数据显示盐化根中PM Na+/H+反向运输系统的激活最有可能是由于编码PM Na+/H+逆向转运蛋白，盐过度敏感1（SOS1）的两个基因GuSOS1和GuAHA的上调，和H+-ATPase。这些盐敏感激动剂之间发生明显的相互作用，以加速G. uralensis根中盐响应信号通路基因的转录。

例如，Ca2+，H2O2，NO和eATP促进GuSOS3（盐过度敏感3）和/或GuCIPK（CBL相互作用蛋白激酶）的转录以激活盐化甘草根中的主要Ca2+-SOS信号传导途径。eATP，一种新的G. uralensis盐响应的参与者，增加了GuSOS3，GuCIPK，GuRbohD（呼吸爆发氧化酶同源蛋白D），GuNIR（硝酸还原酶），GuMAPK3和GuMAPK6（丝裂原活化蛋白激酶3）的转录和6）。此外，在NaCl胁迫的G. uralensis根中，H2O2增强了GuMAPK3和GuMAPK6的表达水平。

我们的结果表明，eATP触发下游组分并与Ca2+，H2O2和NO信号相互作用以维持K+/Na+稳态。我们提出多重信号网络调节NaCl胁迫的G. uralensis根中的K+/Na+稳态。

(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.

 

文章链接：
https://www.frontiersin.org/articles/10.3389/fpls.2017.01403/full

 

标签: H+, K+, Na+, 甘草, 盐敏感信号网络