A Novel RGL2-DOF6 Complex Contributes to Primary Seed Dormancy in Arabidopsis thaliana by Regulating a GATA Transcription Factor

作     者：Pratibha Ravindran Vivek Verma Petra Stamm Prakash P. Kumar 

作者机构：Department of Biological Sciences Faculty of Science National University of Singapore Singapore 117543 Singapore present address: Department of Biosciences Durham University South Road Durham DH1 3LE UK 

出 版 物：《Molecular Plant》 (分子植物（英文版）)

年 卷 期：2017年第10卷第10期

页      面：1307-1320页

核心收录：

学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 07[理学] 0901[农学-作物学] 0902[农学-园艺学] 

基　　金：project was supported in part by the National Research Foundation, Prime Minister's Office, Singapore under its Competitive Research Program P.R. was a recipient of a research scholarship from the National University of Singapore (NUS) 

主　　题：seed germination primary dormancy DELLA RGL2 DOF6 gibberellin 

摘      要：The DELLA protein RGA-LIKE2 （RGL2） is a key transcriptional repressor of gibberellic acid （GA） signaling that regulates seed germination. We identified GATA12, a gene encoding a GATA-type zinc finger transcription factor, as one of the downstream targets of RGL2 in Arabidopsis thaliana. Our data show that freshly harvested （unstratified） seeds of GATA 12 antisense suppression lines have reduced dormancy compared with the wild-type, while ectopic expression lines show enhanced seed dormancy. We show that GATA12 expression is negatively regulated by GA, and its transcript levels decline dramatically under dormancy- breaking conditions such as dry storage and cold stratification of seeds. GATA12 promoter has several GAMYB- and DOF-associated motifs that are known to be GA- and RGL2-responsive, respectively. Chromatin immunoprecipitation assay showed that a protein complex containing RGL2 can bind to GATA12 promoter and thereby regulate its expression. RGL2 lacks a DNA binding domain and requires a transcription factor to induce GATA12 expression. Our data show that this RGL2-containing protein complex includes DNA BINDING1 ZINC FINGER6 （DOF6）, which is a known negative regulator of germination in freshly harvested seeds. We further show that this novel RGL2-DOF6 complex is required for activating GATA12 expression, thus revealing a molecular mechanism to enforce primary seed dormancy.