Plant height has a major effect on grain yield in crops such as rice （Oryza sativa）, and the hormone gibberellic acid （GA） regulates many developmental processes that feed into plant height. Rice ELONGATED UPPERMO...Plant height has a major effect on grain yield in crops such as rice （Oryza sativa）, and the hormone gibberellic acid （GA） regulates many developmental processes that feed into plant height. Rice ELONGATED UPPERMOST INTERNODE1 （Euil） encodes a GA-deactivating enzyme governing elongation of the uppermost internode. The expression of Euil is finely tuned, thereby maintaining homeostasis of endogenous bioactive GA and producing plants of normal plant height. Here, we identified a dominant dwarf mutant, dEuil, caused by the deletion of an RY motif-containing cis-silencing element （SE1） in the intron of Euil. Detailed genetic and molecular analysis of SE1 revealed that this intronic cis element recruits at least one trans-acting repressor complex, containing the B3 repressors OsVAL2 and OsGD1, the SAP18 corepressor, and the histone deacetylase OsHDA710, to negatively regulate the expression of Euil. This com- plex generates closed chromatin at Euil, suppressing Euil expression and modulating GA homeostasis. Loss of SE1 or dysfunction of the complex components impairs histone deacetylation and H3K27me3 methylation of Euil chromatin, thereby increasing Euil transcription and decreasing bioactive GA, producing dwarfism in rice. Together, our results reveal a novel silencing mechanism in which the intronic cis element SE1 negatively regulates Euil expression via repressor complexes that modulate histone deacetylation and/or methylation.展开更多
基金This work was supported by the National Key Research and Development Program of China （2016YFD0100804） and grants from the National Natural Science Foundation of China （31471564）to L.C.
文摘Plant height has a major effect on grain yield in crops such as rice （Oryza sativa）, and the hormone gibberellic acid （GA） regulates many developmental processes that feed into plant height. Rice ELONGATED UPPERMOST INTERNODE1 （Euil） encodes a GA-deactivating enzyme governing elongation of the uppermost internode. The expression of Euil is finely tuned, thereby maintaining homeostasis of endogenous bioactive GA and producing plants of normal plant height. Here, we identified a dominant dwarf mutant, dEuil, caused by the deletion of an RY motif-containing cis-silencing element （SE1） in the intron of Euil. Detailed genetic and molecular analysis of SE1 revealed that this intronic cis element recruits at least one trans-acting repressor complex, containing the B3 repressors OsVAL2 and OsGD1, the SAP18 corepressor, and the histone deacetylase OsHDA710, to negatively regulate the expression of Euil. This com- plex generates closed chromatin at Euil, suppressing Euil expression and modulating GA homeostasis. Loss of SE1 or dysfunction of the complex components impairs histone deacetylation and H3K27me3 methylation of Euil chromatin, thereby increasing Euil transcription and decreasing bioactive GA, producing dwarfism in rice. Together, our results reveal a novel silencing mechanism in which the intronic cis element SE1 negatively regulates Euil expression via repressor complexes that modulate histone deacetylation and/or methylation.
