百年假说终获解析:穿梭的LAZY蛋白“唤醒”植物对重力的感应  

Century-old Hypothesis Finally Revealed:the Shuttling LAZY Proteins“Awaken”Gravity Sensing in Planta

作　　者：王文广 王永红 Wenguang Wang;Yonghong Wang(College of Life Sciences,Shandong Agricultural University,Tai’an 271018,China;Institute of Genetics and Developmental Biology,Chinese Academy of Sciences,Beijing 100101,China)

机构地区：[1]山东农业大学生命科学学院,泰安271018 [2]中国科学院遗传与发育生物学研究所,北京100101

出　　处：《植物学报》2023年第5期677-681,共5页Chinese Bulletin of Botany

基　　金：山东省自然科学基金面上项目(No.ZR2022MC082)。

摘　　要：植物感受到重力刺激后可通过重力反应协调自身各器官的生长方向。在植物重力反应过程中,重力感应和信号转导一直都是植物学领域关注的焦点。经典的“淀粉-平衡石”假说认为植物对重力的感应是通过淀粉体(富含淀粉的质体)沉降来实现。此外,研究发现LAZY蛋白通过调控生长素的不对称分布参与植物重力反应。然而,淀粉体沉降引发的重力信号转导及其与LAZY蛋白之间协作的分子机制仍不清楚。近期,清华大学陈浩东研究团队发现重力刺激能够诱导拟南芥(Arabidopsis thaliana)MKK5-MPK3激酶途径,进而对LAZY蛋白进行磷酸化,LAZY蛋白的磷酸化增强其与淀粉体表面TOC蛋白的互作,促进LAZY蛋白在淀粉体表面富集。淀粉体沉降引导LAZY蛋白在新的底侧质膜极性再定位。该研究深入解析了植物重力信号转导的分子机制,建立了植物重力感应与LAZY蛋白介导的生长素不对称分布之间的联系,是植物向重力性研究领域的重大突破。Plants can coordinate the growth direction of their various organs upon the gravity stimulus.In the process of plant gravitropism,gravity sensing and gravity signal transduction have always been the focus of attention in the field of plants.The classical“starch-statolith”hypothesis proposes that plants sense gravity through the sedimentation of amyloplasts that contain starch granules.In addition,previous studies have shown that LAZY proteins regulate plant gravitropism by mediating the asymmetric distribution of auxin.However,the molecular mechanism underlying how sedimentation of amyloplasts triggers gravity signal transduction and its coordination with LAZY proteins remains unclear.Recently,Professor Haodong Chen’s team from Tsinghua University reveals that gravistimulation induces the phosphorylation of LAZY proteins via MKK5-MPK3 kinase pathway in Arabidopsis,which modulates the phosphorylation of LAZY proteins.The phosphorylated LAZY proteins can enhance their interaction with the TOC proteins on the surface of amyloplasts,leading to the enrichment of LAZY proteins on the surface of amyloplasts and the polarity relocation on the new bottom of plasma membrane.This study illustrates the molecular mechanism underlying gravity signal transduction in plants and establishes the molecular connection between gravity sensing and LAZY mediated auxin asymmetric distribution,which is a major breakthrough in the field of plant gravitropism.

关 键 词：重力反应 淀粉体 极性定位 磷酸化 “淀粉-平衡石”假说 LAZY TOC MPK 

分 类 号：Q945[生物学—植物学]