DDG1 and G Protein α Subunit RGA1 Interaction Regulates Plant Height and Senescence in Rice(Oryza sativa)

Many studies have already shown that dwarfism and moderate delayed leaf senescence positively impact rice yield,but the underlying molecular mechanism of dwarfism and leaf senescence remains largely unknown.Here,using map-based cloning,we identified an allele of DEP2,DDG1,which controls plant height and leaf senescence in rice.The ddg1 mutant displayed dwarfism,short panicles,and delayed leaf senescence.Compared with the wild-type,ddg1 was insensitive to exogenous gibberellins(GA)and brassinolide(BR).DDG1 is expressed in various organs,especially in stems and panicles.Yeast two-hybrid assay,bimolecular fluorescent complementation and luciferase complementation image assay showed that DDG1 interacts with theα-subunit of the heterotrimeric G protein.Disruption of RGA1 resulted in dwarfism,short panicles,and darker-green leaves.Furthermore,we found that ddg1 and the RGA1 mutant was more sensitive to salt treatment,suggesting that DDG1 and RGA1 are involved in regulating salt stress response in rice.Our results show that DDG1/DEP2 regulates plant height and leaf senescence through interacting with RGA1.