Root System Depth in Arabidopsis Is Shaped by EXOCYST70A3 via the Dynamic Modulation of Auxin Transport

First author: Takehiko Ogura; Affiliations: Salk Institute for Biological Studies (萨克生物研究所): La Jolla, USA

Corresponding author: Wolfgang Busch

Root system architecture (RSA), the distribution of roots in soil, plays a major role in plant survival. RSA is shaped by multiple developmental processes that are largely governed by the phytohormone auxin, suggesting that auxin regulates responses of roots that are important for local adaptation. However, auxin has a central role in numerous processes, and it is unclear which molecular mechanisms contribute to the variation in RSA for environmental adaptation. Using natural variation in Arabidopsis, we identify EXOCYST70A3 as a modulator of the auxin system that causes variation in RSA by acting on PIN4 protein distribution. Allelic variation and genetic perturbation of EXOCYST70A3 lead to alteration of root gravitropic responses, resulting in a different RSA depth profile and drought resistance. Overall our findings suggest that the local modulation of the pleiotropic auxin pathway can gives rise to distinct RSAs that can be adaptive in specific environments.

植物根系统结构RSA是指植物的根在土壤中的分布，其在植物的生存中扮演着非常重要的作用。已知多个发育进程能够影响RSA，且大部分是通过植物激素生长素来发挥作用，说明生长素能够调控植物根的响应，这对于植物的区域化适应十分重要。然而，生长素在许多生物学进程中都发挥重要作用，具体是哪个分子机制作用于植物在不同环境适应下RSA的变异还不清楚。利用拟南芥的自然变异，作者鉴定到了EXOCYST70A3基因作为生长素系统的调控因子作用于RSA的变异，其具体通过介导PIN4蛋白的分布发挥功能。对于EXOCYST70A3基因的等位基因变异及遗传扰动会改变根对于重力的响应，产生不同深度的RSA，同时对于干旱的抗性存在差异。本文的研究显示对于多效性生长素通路的局部调控可以获得完全不同的根系结构，以适应特定的生存环境。

通讯：Wolfgang Busch (https://www.salk.edu/scientist/wolfgang-busch/)

个人简介：2004年，德国图宾根大学，学士；2009年，图宾根大学，博士。

研究方向：植物根系统。

doi: https://doi.org/10.1016/j.cell.2019.06.021

Journal: Cell

Published date: July 11, 2019