Growth asymmetry precedes differential auxin response during apical hook initiation in Arabidopsis  

作　　者：Yang Peng Dan Zhang Yuping Qiu Zhina Xiao Yusi Ji Wenyang Li Yiji Xia Yichuan Wang Hongwei Guo 

机构地区：[1]Department of Biology,Institute of Plant and Food Science,School of Life Sciences,Southern University of Science and Technology,Shenzhen 518055,China [2]Department of Biology,Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes,School of Life Sciences,Southern University of Science and Technology,Shenzhen 518055,China [3]Department of Biology,Faculty of Science,Hong Kong Baptist University,Kowloon Tong,Hong Kong 999077,China [4]Microlens Technologies,Beijing 100086,China

出　　处：《Journal of Integrative Plant Biology》2022年第1期5-22,共18页植物学报（英文版）

基　　金：funded by the Southern University of Science and Technology for scientific research start-ups(Grant No.Y01226124 to H.G.);National Natural Science Foundation of China(Grant No.31700239 to Y.W.);Shenzhen Science and Technology Innovation Program(Grant No.JCYJ20170817105503416 to W.L.);Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes(SUSTech)(2019KSYS006 to H.G.)。

摘　　要：The development of a hook-like structure at the apical part of the soil-emerging organs has fascinated botanists for centuries,but how it is initiated remains unclear.Here,we demonstrate with highthroughput infrared imaging and 2-D clinostat treatment that,when gravity-induced root bending is absent,apical hook formation still takes place.In such scenarios,hook formation begins with a de novo growth asymmetry at the apical part of a straightly elongating hypocotyl.Remarkably,suchde novo asymmetric growth,but not the following hook enlargement,precedes the establishment of a detectable auxin response asymmetry,and is largely independent of auxin biosynthesis,transport and signaling.Moreover,we found that functional cortical microtubule array is essential for the following enlargement of hook curvature.When microtubule array was disrupted by oryzalin,the polar localization of PIN proteins and the formation of an auxin maximum became impaired at the to-be-hook region.Taken together,we propose a more comprehensive model for apical hook initiation,in which the microtubuledependent polar localization of PINs may mediate the instruction of growth asymmetry that is either stochastically taking place,induced by gravitropic response,or both,to generate a significant auxin gradient that drives the full development of the apical hook.

关 键 词：apical hook initiation asymmetric auxin response cortical microtubule array de novo growth asymmetry PINS 

分 类 号：Q945[生物学—植物学]