Mediator complex subunit MED25 physically interacts with DST to regulate spikelet number in rice

作     者：Lihao Lin Minmin Du Shuyu Li Chuanlong Sun Fangming Wu Lei Deng Qian Chen Chuanyou Li Lihao Lin;Minmin Du;Shuyu Li;Chuanlong Sun;Fangming Wu;Lei Deng;Qian Chen;Chuanyou Li

作者机构：State Key Laboratory of Plant GenomicsNational Centre for Plant Gene Research(Beijing)Institute of Genetics and Developmental BiologyThe Innovative Academy of Seed DesignThe Chinese Academy of SciencesBeijing 100101China State Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTaian 271018China 

出 版 物：《Journal of Integrative Plant Biology》 (植物学报（英文版）)

年 卷 期：2022年第64卷第4期

页      面：871-883页

核心收录：

学科分类：0710[理学-生物学] 09[农学] 0901[农学-作物学] 

基　　金：supported by the National Key Research and Development Program of China (Grant No. 2019YFD1000300) Agricultural Seed Project of Shandong Province (Grant Nos 2020LZGC005, 2021LZGC0017) the Tai-Shan Scholar Program from Shandong Province (Grant No. tsxk20150901) the K. C. Wong Education Foundation. 

主　　题：DST MED25 OsCKX2 rice spikelet number 

摘      要：Grain number is a flexible trait and contributes significantly to grain yield.In rice,the zinc finger transcription factor DROUGHT AND SALT TOLERANCE(DST)controls grain number by directly regulating cytokinin oxidase!dehydrogenase 2(OsCKX2)expression.Although specific upstream regulators of the DST-OsCKX2 module have been identified,the mechanism employed by DST to regulate the expression of OsCKX2 remains unclear.Here,we demonstrate that DST-interacting protein 1(DIP1),known as Mediator subunit OsMED25,acts as an interacting coactivator of DST.Phenotypic analyses revealed that OsMED25-RNAi and the osmed25 mutant plants exhibited enlarged panicles,with enhanced branching and spikelet number,similar to the dst mutant.Genetic analysis indicated that OsMED25 acts in the same pathway as the DST-OsCKX2 module to regulate spikelet number per panicle.Further biochemical analysis showed that OsMED25 physically interacts with DST at the promoter region of OsCKX2,and then recruits RNA polymerase II(Pol II)to activate OsCKX2 transcription.Thus,OsMED25 was involved in the communication between DST and Pol II general transcriptional machinery to regulate spikelet number.In general,our findings reveal a novel function of OsMED25 in DST-OsCKX2 modulated transcriptional regulation,thus enhancing our un derstanding of the regulatory mechanism underlying DST-OsCKX2-mediated spikelet number.