Histone Deacetylase 701 (HDT701) Induces Flowering in Rice by Modulating Expression of OsIDS1

摘要

Rice is a facultative short-day (SD) plant in which flowering is induced under SD conditions or by other environmental factors and internal genetic programs. Overexpression of Histone Deacetylase 701 ( HDT701 ) accelerates flowering in hybrid rice. In this study, mutants defective in HDT701 flowered late under both SD and long-day conditions. Expression levels of florigens Heading date 3a ( Hd3a ) and Rice Flowering Locus T1 ( RFT1 ), and their immediate upstream floral activator Early heading date 1 ( Ehd1 ), were significantly decreased in the hdt701 mutants, indicating that HDT701 functions upstream of Ehd1 in controlling flowering time. Transcript levels of OsINDETERMINATE SPIKELET 1 ( OsIDS1 ), an upstream repressor of Ehd1 , were significantly increased in the mutants while those of OsGI and Hd1 were reduced. Chromatin-immunoprecipitation assays revealed that HDT701 directly binds to the promoter region of OsIDS1 . These results suggest that HDT701 induces flowering by suppressing OsIDS1.