RGB1 Regulates Rice Panicle Architecture and Grain Filling Through Monitoring Cytokinin Level in Inflorescence Meristem and Grain Abscisic Acid Level During Filling Stage

摘要

RGB1 regulated not only rice panicle architecture but also the grain filling process.Suppression of RGB1 expression resulted in a denser panicle and smaller grain size and weight,which was largely due to the lower endogenous cytokinin(CK)level caused by the increased expression of cytokinin oxidase genes in the inflorescence meristem.Suppression of RGB1 expression also significantly delayed the grain development and reduced the starch accumulation rate through reducing grain abscisic acid(ABA)accumulation during early filling stage.Exogenous ABA can partially rescue the detrimental effects of suppression of RGB1 expression on starch accumulation and grain weight.In conclusion,RGB1 regulated rice panicle architecture and grain filling through monitoring CK level in the inflorescence meristem and grain ABA level during filling stage.