Endodermal ABA Signaling Promotes Lateral Root Quiescence during Salt Stress in Arabidopsis Seedlings
Endodermal ABA Signaling Promotes Lateral Root Quiescence during Salt Stress in Arabidopsis Seedlings
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DOI：
10.1105/tpc.112.107227
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发表时间：
2013-01-01
期刊：
影响因子：
11.6
通讯作者：
Dinneny, Jose R.
中科院分区：
文献类型：
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作者：
Duan, Lina;Dietrich, Daniela;Dinneny, Jose R.
内胚层组织层存在于维管植物的根部，起到半透屏障的作用，调节溶质从土壤到维管束的运输。作为溶质的门户，内皮层也可能作为感知和响应环境中有用或有毒物质的重要部位。在这里，我们发现高盐度是一种广泛影响农业用地的环境压力，它通过主要在内皮层中运作的信号网络来调节幼苗根系的生长。我们报告说，盐胁迫会导致芽后侧根（LR）的静止期延长，从而在恢复开始之前生长速度被抑制几天。静止与 LR 中持续的脱落酸 (ABA) 反应相关，并且依赖于 ABA 生物合成、信号传导和转录调控所需的基因。我们使用组织特异性策略来识别 ABA 信号传导调节生长的关键细胞层。在内皮层中，ABA insensitive1-1 突变蛋白的错误表达主要抑制 ABA 信号传导，导致盐胁迫条件下 LR 生长大幅恢复。拮抗 ABA 途径的赤霉酸信号传导也主要在内皮层中起作用，我们定义了这两种激素之间的串扰。我们的结果确定内皮层是具有 ABA 依赖性保护的门户，可防止根生长到盐分环境中。
The endodermal tissue layer is found in the roots of vascular plants and functions as a semipermeable barrier, regulating the transport of solutes from the soil into the vascular stream. As a gateway for solutes, the endodermis may also serve as an important site for sensing and responding to useful or toxic substances in the environment. Here, we show that high salinity, an environmental stress widely impacting agricultural land, regulates growth of the seedling root system through a signaling network operating primarily in the endodermis. We report that salt stress induces an extended quiescent phase in postemergence lateral roots (LRs) whereby the rate of growth is suppressed for several days before recovery begins. Quiescence is correlated with sustained abscisic acid (ABA) response in LRs and is dependent upon genes necessary for ABA biosynthesis, signaling, and transcriptional regulation. We use a tissue-specific strategy to identify the key cell layers where ABA signaling acts to regulate growth. In the endodermis, misexpression of the ABA insensitive1-1 mutant protein, which dominantly inhibits ABA signaling, leads to a substantial recovery in LR growth under salt stress conditions. Gibberellic acid signaling, which antagonizes the ABA pathway, also acts primarily in the endodermis, and we define the crosstalk between these two hormones. Our results identify the endodermis as a gateway with an ABA-dependent guard, which prevents root growth into saline environments.