Auxin-sensitive Aux/IAA proteins mediate drought tolerance in Arabidopsis by regulating glucosinolate levels

First author: Mohammad Salehin; Affiliations: University of California, San Diego (加州大学圣地亚哥分校): La Jolla, USA

Corresponding author: Mark Estelle 

A detailed understanding of abiotic stress tolerance in plants is essential to provide food security in the face of increasingly harsh climatic conditions. Glucosinolates (GLSs) are secondary metabolites found in the Brassicaceae that protect plants from herbivory and pathogen attack. Here we report that in Arabidopsis, aliphatic (脂肪族) GLS levels are regulated by the auxin-sensitive Aux/IAA repressors IAA5, IAA6, and IAA19. These proteins act in a transcriptional cascade that maintains expression of GLS levels when plants are exposed to drought conditions. Loss of IAA5/6/19 results in reduced GLS levels and decreased drought tolerance. Further, we show that this phenotype is associated with a defect in stomatal regulation. Application of GLS to the iaa5,6,19 mutants restores stomatal regulation and normal drought tolerance. GLS action is dependent on the receptor kinase GHR1, suggesting that GLS may signal via reactive oxygen species. These results provide a novel connection between auxin signaling, GLS levels and drought response.

对于植物在非生物胁迫下的抗性机制理解将有助于在日益增加的恶劣环境条件下保证食物安全。硫代葡萄糖甙GLS是十字花科中发现的次生代谢物，其能够保护植物免受草食动物以及病原菌的袭击。本文中，作者报道了拟南芥中脂肪族GLS的水平受到对生长素敏感的Aux/IAA抑制蛋白IAA5/6/19的调控。当植物暴露在干旱条件下时，这些蛋白通过转录级联维持GLS的水平。IAA5/6/19的功能缺失导致了GLS水平的降低，并且降低了植株的干旱抗性。此外，作者的研究显示突变体的表型与气孔调控的缺陷有关。对iaa5,6,19突变体使用GLS能够恢复气孔调控及正常的干旱抗性。GLS的作用依赖于受体激酶GHR1，说明GLS可能通过活性氧物质传递信号。本文的研究结果提供了一个生长素信号转导、GLS水平以及植株干旱响应之间的关联。

通讯：Mark Estelle（https://biology.ucsd.edu/research/faculty/mestelle)

个人简介：2003-2007年，武汉大学，学士；2007-2012年，北京大学，博士；2010-2012年，耶鲁大学，联合培养；2012-2014年，耶鲁大学，博士后。

研究方向：生长素介导的植物生长发育分子机制。

doi: https://doi.org/10.1038/s41467-019-12002-1

Journal: Nature Communications

Published online: September 06, 2019