Brassinosteroid（BR） and gibberellin（GA） are two predominant plant hormones that regulate plant cell elongation. Mutants disrupt the biosynthesis of these hormones and display different degrees of dwarf phenotypes ...Brassinosteroid（BR） and gibberellin（GA） are two predominant plant hormones that regulate plant cell elongation. Mutants disrupt the biosynthesis of these hormones and display different degrees of dwarf phenotypes in rice. Although the role of each plant hormone in promoting the longitudinal growth of plants has been extensively studied using genetic methods, their relationship is still poorly understood. In this study, we used two specific inhibitors targeting BR and GA biosynthesis to investigate the roles of BR and GA in growth of rice seedlings. Yucaizol, a specific inhibitor of BR biosynthesis, and Trinexapac-ethyl, a commercially available inhibitor of GA biosynthesis, were used. The effect of Yucaizol on rice seedlings indicated that Yucaizol significantly retarded stem elongation. The IC_（50） value was found to be approximately 0.8 μmol/L. Yucaizol also induced small leaf angle phenocopy in rice seedlings, similarly to BR-deficient rice, while Trinexapac-ethyl did not. When Yucaizol combined with Trinexapac-ethyl was applied to the rice plants, the mixture of these two inhibitors retarded stem elongation of rice at lower doses. Our results suggest that the use of a BR biosynthesis inhibitor combined with a GA biosynthesis inhibitor may be useful in the development of new technologies for controlling rice plant height.展开更多
The phytohormone gibberellin（GA） plays essential roles in plant growth and development. Here,we report that OsINO80, a conserved ATP-dependent chromatin-remodeling factor in rice（Oryza sativa）, functions in both G...The phytohormone gibberellin（GA） plays essential roles in plant growth and development. Here,we report that OsINO80, a conserved ATP-dependent chromatin-remodeling factor in rice（Oryza sativa）, functions in both GA biosynthesis and diverse biological processes. OsINO80-knockdown mutants, derived from either T-DNA insertion or RNA interference, display typical GA-deficient phenotypes, including dwarfism, reduced cell length, late flowering, retarded seed germination and impaired reproductive development. Consistently, transcriptome analyses reveal that OsINO80 knockdown results in downregulation by more than two-fold of over 1,000 genes, including the GA biosynthesis genes CPS_1 and GA_3ox_2, and the dwarf phenotype of OsINO80-knockdown mutants can be rescued by the application of exogenous GA3. Chromatin immunoprecipitation（Ch IP） experiments show that OsINO80 directly binds to the chromatin of CPS1 and GA_3ox_2 loci. Biochemical assays establish that OsINO80 specially interacts with histone variant H_2A.Z and the H_2A.Z enrichments at CPS_1 and GA_3ox_2 are decreased in OsINO80-knockdown mutants. Thus, our study identified a rice chromatin-remodeling factor,OsINO80, and demonstrated that OsINO80 is involved in regulation of the GA biosynthesis pathway and plays critical functions for many aspects of rice plant growth and development.展开更多
基金supported in part by a grant from Akita President’s research project to Keimei OH
文摘Brassinosteroid（BR） and gibberellin（GA） are two predominant plant hormones that regulate plant cell elongation. Mutants disrupt the biosynthesis of these hormones and display different degrees of dwarf phenotypes in rice. Although the role of each plant hormone in promoting the longitudinal growth of plants has been extensively studied using genetic methods, their relationship is still poorly understood. In this study, we used two specific inhibitors targeting BR and GA biosynthesis to investigate the roles of BR and GA in growth of rice seedlings. Yucaizol, a specific inhibitor of BR biosynthesis, and Trinexapac-ethyl, a commercially available inhibitor of GA biosynthesis, were used. The effect of Yucaizol on rice seedlings indicated that Yucaizol significantly retarded stem elongation. The IC_（50） value was found to be approximately 0.8 μmol/L. Yucaizol also induced small leaf angle phenocopy in rice seedlings, similarly to BR-deficient rice, while Trinexapac-ethyl did not. When Yucaizol combined with Trinexapac-ethyl was applied to the rice plants, the mixture of these two inhibitors retarded stem elongation of rice at lower doses. Our results suggest that the use of a BR biosynthesis inhibitor combined with a GA biosynthesis inhibitor may be useful in the development of new technologies for controlling rice plant height.
基金supported by the National Basic Research Program of China (973 Program, Grants no.2012CB910500)the National Natural Science Foundation of China (31570315, 91519308, and 31371304)
文摘The phytohormone gibberellin（GA） plays essential roles in plant growth and development. Here,we report that OsINO80, a conserved ATP-dependent chromatin-remodeling factor in rice（Oryza sativa）, functions in both GA biosynthesis and diverse biological processes. OsINO80-knockdown mutants, derived from either T-DNA insertion or RNA interference, display typical GA-deficient phenotypes, including dwarfism, reduced cell length, late flowering, retarded seed germination and impaired reproductive development. Consistently, transcriptome analyses reveal that OsINO80 knockdown results in downregulation by more than two-fold of over 1,000 genes, including the GA biosynthesis genes CPS_1 and GA_3ox_2, and the dwarf phenotype of OsINO80-knockdown mutants can be rescued by the application of exogenous GA3. Chromatin immunoprecipitation（Ch IP） experiments show that OsINO80 directly binds to the chromatin of CPS1 and GA_3ox_2 loci. Biochemical assays establish that OsINO80 specially interacts with histone variant H_2A.Z and the H_2A.Z enrichments at CPS_1 and GA_3ox_2 are decreased in OsINO80-knockdown mutants. Thus, our study identified a rice chromatin-remodeling factor,OsINO80, and demonstrated that OsINO80 is involved in regulation of the GA biosynthesis pathway and plays critical functions for many aspects of rice plant growth and development.
