TIR1/AFB-Aux/IAA auxin perception mediates rapid cell wall acidification and growth of Arabidopsis hypocotyls
TIR1/AFB-Aux/IAA auxin perception mediates rapid cell wall acidification and growth of Arabidopsis hypocotyls
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DOI：
10.7554/elife.19048
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发表时间：
2016-09-14
期刊：
影响因子：
7.7
通讯作者：
Friml, Jiri
中科院分区：
文献类型：
--
作者：
Fendrych, Matyas;Leung, Jeffrey;Friml, Jiri
尽管植物由固定的细胞组成，但它们会沿着定向刺激重新定向。生长素激素在受刺激的器官中重新分布，导致生长和弯曲的差异。生长素的应用会引发植物细胞壁的快速酸化和气生器官的伸长，但介导这些效应的分子参与者仍然存在争议。在这里，我们使用基因编码的 pH 和生长素信号传感器、可用于拟南芥黄化下胚轴的药理学和遗传操作来阐明生长素是如何被感知的以及下游生长是如何执行的。我们发现，生长素诱导的酸化是通过 H+-ATP 酶的局部激活而发生的，在重力响应的情况下，这种酸化仅限于下器官侧。这种生长素刺激的酸化和生长需要 TIR1/AFB-Aux/IAA 核生长素感知。此外，生长素诱导的基因转录，特别是 SAUR 蛋白是这种生长的关键下游介质。我们的研究为酸生长理论提供了强有力的实验支持，并阐明了上游生长素感知机制的贡献。
Despite being composed of immobile cells, plants reorient along directional stimuli. The hormone auxin is redistributed in stimulated organs leading to differential growth and bending. Auxin application triggers rapid cell wall acidification and elongation of aerial organs of plants, but the molecular players mediating these effects are still controversial. Here we use genetically-encoded pH and auxin signaling sensors, pharmacological and genetic manipulations available for Arabidopsis etiolated hypocotyls to clarify how auxin is perceived and the downstream growth executed. We show that auxin-induced acidification occurs by local activation of H+-ATPases, which in the context of gravity response is restricted to the lower organ side. This auxin-stimulated acidification and growth require TIR1/AFB-Aux/IAA nuclear auxin perception. In addition, auxin-induced gene transcription and specifically SAUR proteins are crucial downstream mediators of this growth. Our study provides strong experimental support for the acid growth theory and clarified the contribution of the upstream auxin perception mechanisms.