Research on the molecular mechanism of florigen in rice.

Flowering time is a key trait essential for environmental adaptation of plants.Studies in Arabidopsis have revealed that flowering time is controlled by an intricate regulatory network composing of four signaling pathways,namely the photoperiod pathway, the vernalization pathway,the autonomous pathway and the GA pathway.Florigen FT (FLOWERING LOCUS T) is one of the most important common components integrating the effects of these pathways.Hd3a is the rice ortholog of Arabidopsis FT.The Hd3a (HEADING DATE 3a) protein is the candidate of florigen in rice,moving up from light induced leaf to the shoot apex,and eventually promoting flowering.Although the function of FT and Hd3a are conserved,the upstream regulatory factors and associated mechanisms on Hd3a expression are different from that in Arabidopsis.This article reviews the recent progress on rice florigen Hd3a and its regulatory mechanism,intending to provide valuable information for further studies.