Arabidopsis STAY-GREEN2 Is a Negative Regulator of Chlorophyll Degradation during Leaf Senescence

作     者：Yasuhito Sakuraba So-Yon Park Ye-Sol Kim Seung-Hyun Wang Soo-Cheul Yoo Stefan Hortensteiner Nam-Chon Paek 

作者机构：Department of Plant Science Plant Genomics and Breeding Institute Research Institute of Agriculture and Life Sciences Seoul NationalUniversity Seoul 151-921 Korea Present address: Department of Plant Pathology Physiology and Weed Science Virginia Tech Blacksburg VA 24061 USA Present address: Advanced Radiation Technology Institute Korea Atomic Energy Research Institute Jeongeup 580-185 Korea Department of Plant & Environmental Science Hankyong National University Ansung 456-749 Korea Institute of Plant Biology University of Zurich CH-8008 Zurich Switzerland 

出 版 物：《Molecular Plant》 (分子植物（英文版）)

年 卷 期：2014年第7卷第8期

页      面：1288-1302页

核心收录：

学科分类：08[工学] 09[农学] 0901[农学-作物学] 0822[工学-轻工技术与工程] 

基　　金：support of "Cooperative Research Program for Agriculture Science & Technology Development Map-based cloning and function analysis of functional stay-green and yield-related QTL genes and development of global GM rice Rural Development Administration Republic of Korea (to N.-C.P) the Swiss National Science Foundation (to S.H.) 

主　　题：Arabidopsis thaliana stay-green SGR1 SGR2 chlorophyll degradation leaf senescence abiotic stress. 

摘      要：Chlorophyll （Chl） degradation causes leaf yellowing during senescence or under stress conditions. For Chl breakdown, STAY-GREEN1 （SGR1） interacts with Chl catabolic enzymes （CCEs） and light-harvesting complex II （LHCII） at the thylakoid membrane, possibly to allow metabolic channeling of potentially phototoxic Chl breakdown intermediates. Among these Chl catabolic components, SGR1 acts as a key regulator of leaf yellowing. In addition to SGR1 （At4g22920）, the Arabidopsis thaliana genome contains an additional homolog, SGR2 （At4g11910）, whose biological function remains elusive. Under senescence-inducing conditions, SGR2 expression is highly up-regulated, similarly to SGR1 expression. Here we show that SGR2 function counteracts SGR1 activity in leaf Chl degradation; SGR2-overexpressing plants stayed green and the sgr2-1 knockout mutant exhibited early leaf yellowing under age-, dark-, and stress-induced senescence conditions. Like SGR1, SGR2 interacted with LHCII but, in contrast to SGR1, SGR2 interactions with CCEs were very limited. Furthermore, SGR1 and SGR2 formed homo- or heterodimers, strongly suggesting a role for SGR2 in negatively regulat- ing Chl degradation by possibly interfering with the proposed CCE-recruiting function of SGR1. Our data indicate an antagonistic evolution of the functions of SGR1 and SGR2 in Arabidopsis to balance Chl catabolism in chloroplasts with the dismantling and remobilizing of other cellular components in senescing leaf cells.