Arabidopsis IAR4 Modulates Primary Root Growth Under Salt Stress Through ROS-Mediated Modulation of Auxin Distribution
Arabidopsis IAR4 Modulates Primary Root Growth Under Salt Stress Through ROS-Mediated Modulation of Auxin Distribution
复制标题
拟南芥 IAR4 通过 ROS 介导的生长素分布调节来调节盐胁迫下的初生根生长
DOI：
10.3389/fpls.2019.00522
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发表时间：
2019-04-25
影响因子：
5.6
通讯作者：
Hu, Honghong
中科院分区：
文献类型：
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作者：
Fu, Yang;Yang, Yong;Hu, Honghong
高盐度是植物面临的主要环境压力之一。根是最初和直接感知信号的器官。然而，植物根系如何在分子和生理水平上感知和响应盐度仍然知之甚少。本文报道了IAA-CONJUGATE-RESISTANT 4 （IAR4）在盐胁迫条件下初生根生长中起关键作用。IAR4突变导致对盐胁迫条件的敏感性增加，两个IAR4突变等位基因的初生根生长受到强烈抑制，成活率降低。在NaCl处理下，iar4突变体积累了更多的Na+，表现出更大的Na+/K+比值。此外，由于活性氧清除能力降低，iar4突变体中积累了更多的活性氧（ROS）。NaCl处理显著抑制了ProPIN1:PIN1-GFP、ProPIN2:PIN2-GFP、ProPIN3:PIN3-GFP和ProDR5:GFP的表达水平，抑制了iar4根分生组织活性。GSH或生长素处理可显著恢复iar4突变体的PIN表达、生长素分布和初生根生长，提示ROS是盐胁迫与生长素反应之间的重要中介。我们的数据支持IAR4整合ROS和生长素途径，通过调节pin介导的生长素运输来调节盐胁迫条件下初生根生长的模型。
High salinity is one of the major environmental stresses that plants encounter. Roots are the initial and direct organs to perceive the signal. However, how plant roots perceive and respond to salinity at the molecular and physiological levels is still poorly understood. Here, we report that IAA-CONJUGATE-RESISTANT 4 (IAR4) plays a key role in primary root growth under salt stress conditions. Mutation of IAR4 led to increased sensitivity to salt stress conditions, with strongly inhibited primary root growth and reduced survival rate in two iar4 mutant alleles. iar4 mutants accumulated greater Na+ and exhibited a greater Na+/K+ ratio under NaCl treatment. In addition, more reactive oxygen species (ROS) accumulated in the iar4 mutants due to reduced ROS scavenging. NaCl treatment greatly suppressed the expression levels of ProPIN1:PIN1-GFP, ProPIN2:PIN2-GFP, ProPIN3:PIN3-GFP, and ProDR5:GFP, and suppressed root meristem activity in iar4. GSH or auxin treatment greatly recovered the PIN expression, auxin distribution and primary root growth in the iar4 mutants, suggesting ROS is a vital mediator between salt stress and auxin response. Our data support a model in which IAR4 integrates ROS and auxin pathways to modulate primary root growth under salinity stress conditions, by regulation of PIN-mediated auxin transport.