Salt Stress Reduces Root Meristem Size by Nitric Oxide-Mediated Modulation of Auxin Accumulation and Signaling in Arabidopsis
Salt Stress Reduces Root Meristem Size by Nitric Oxide-Mediated Modulation of Auxin Accumulation and Signaling in Arabidopsis
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DOI：
10.1104/pp.15.00030
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发表时间：
2015-05-01
期刊：
影响因子：
7.4
通讯作者：
Lu, Ying-Tang
中科院分区：
文献类型：
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作者：
Liu, Wen;Li, Rong-Jun;Lu, Ying-Tang
植物根系的发育具有很强的可塑性，这使得植物能够适应各种环境胁迫。盐胁迫通过减小根分生组织的大小来抑制根伸长。然而，这一过程背后的机制仍不清楚。在这项研究中，我们利用生理学、药理学和遗传学方法探讨了生长素和一氧化氮 (NO) 是否以及如何参与盐介导的拟南芥 (Arabidopsis thaliana) 根分生组织生长抑制。我们发现盐胁迫通过下调 PINFORMED (PIN) 基因的表达来显着减小根分生组织的大小，从而降低生长素水平。此外，盐胁迫促进了 AUXIN RESISTANT3 (AXR3)/INDOLE-3-ACETIC ACID17 (IAA17) 的稳定，从而抑制了这一过程中的生长素信号传导。此外，盐胁迫刺激NO积累，而用抑制剂Nv-硝基-L-精氨酸甲酯阻断NO产生会损害盐介导的根分生组织大小的减小、PIN下调和AXR3/IAA17的稳定，表明NO参与盐介导的根分生组织生长的抑制。综上所述，这些发现表明盐胁迫通过抑制 PIN 表达（从而降低生长素水平）和通过增加 NO 水平稳定 IAA17（从而抑制生长素信号传导）来抑制根分生组织生长。
The development of the plant root system is highly plastic, which allows the plant to adapt to various environmental stresses. Salt stress inhibits root elongation by reducing the size of the root meristem. However, the mechanism underlying this process remains unclear. In this study, we explored whether and how auxin and nitric oxide (NO) are involved in salt-mediated inhibition of root meristem growth in Arabidopsis (Arabidopsis thaliana) using physiological, pharmacological, and genetic approaches. We found that salt stress significantly reduced root meristem size by down-regulating the expression of PINFORMED (PIN) genes, thereby reducing auxin levels. In addition, salt stress promoted AUXIN RESISTANT3 (AXR3)/INDOLE-3-ACETIC ACID17 (IAA17) stabilization, which repressed auxin signaling during this process. Furthermore, salt stress stimulated NO accumulation, whereas blocking NO production with the inhibitor Nv-nitro-L-arginine-methylester compromised the salt-mediated reduction of root meristem size, PIN down-regulation, and stabilization of AXR3/IAA17, indicating that NO is involved in salt-mediated inhibition of root meristem growth. Taken together, these findings suggest that salt stress inhibits root meristem growth by repressing PIN expression (thereby reducing auxin levels) and stabilizing IAA17 (thereby repressing auxin signaling) via increasing NO levels.