Asymmetric distribution of cytokinins determines root hydrotropism in Arabidopsis thaliana  

作　　者：Jinke Chang Xiaopeng Li Weihao Fu Jiawen Wang Yueyuan Yong Hongyong Shi Zhaojun Ding Hong Kui Xiaoping Gou Kai He Jia Li 

机构地区：[1]Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations,School of Life Sciences,Lanzhou University,730000 Lanzhou,China [2]The Key Laboratory of Plant Development and Environmental Adaptation Biology,Ministry of Education,College of Life Sciences,Shandong University,Qingdao 266237 Shandong,China

出　　处：《Cell Research》2019年第12期984-993,共10页细胞研究（英文版）

基　　金：National Natural Science Foundation of China grants 31530005 and 31720103902 to JL,31770312 and 31471402 to XG,31870235 and 31471305 to KH,the 111 Project(B16022)to JL;the opening research project from the Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations(lzujbky-2015-bt05)to XG.

摘　　要：The phenomenon of plant root tips sensing moisture gradient in soil and growing towards higher water potential is designated as root hydrotropism,which is critical for plants to survive when water is a limited factor.Molecular mechanisms regulating such a fundamental process,however,are largely unknown.Here we report our identification that cytokinins are key signaling molecules directing root growth orientation in a hydrostimulation(moisture gradient)condition.Lower water potential side of the root tip shows more cytokinin response relative to the higher water potential side.Consequently,two cytokinin downstream type-A response regulators,ARR16 and ARR17,were found to be up-regulated at the lower water potential side,causing increased cell division in the meristem zone,which allows the root to bend towards higher water potential side.Genetic analyses indicated that various cytokinin biosynthesis and signaling mutants,including the arr16 arr17 double mutant,are significantly less responsive to hydrostimulation.Consistently,treatments with chemical inhibitors interfering with either cytokinin biosynthesis or cell division completely abolished root hydrotropic response.Asymmetrically induced expression of ARR16 or ARR17 effectively led to root bending in both wild-type and miz1,a previously known hydrotropism-defective mutant.These data demonstrate that asymmetric cytokinin distribution is a primary determinant governing root hydrotropism.

关 键 词：distribution MOISTURE ARABIDOPSIS 

分 类 号：Q94[生物学—植物学]