Overexpression of SRS5 improves grain size of brassinosteroid-related dwarf mutants in rice ( Oryza sativa L.)

摘要

Grain size is a trait that is important for rice ( Oryza sativa L.) yield potential. Many genes regulating grain size have been identified, deepening our understanding of molecular mechanisms of grain size determination in rice. Previously, we cloned S MALL AND R OUND S EED 5 ( SRS5 ) gene (encoding alpha-tubulin) from a small and round seed mutant and revealed that this gene regulates grain length independently of the brassinosteroid (BR) signaling pathway, although BR-related mutants set small grain. In this study, we showed that overexpression of SRS5 can promote grain length and demonstrated that the overexpression of SRS5 in BR-related mutants rescued the shortened grain length, which is an unfavorable phenotype in the yield potential of BR-related mutants, while preserving the useful semi-dwarf and erect leaf phenotypes.