Abstract
Rice Flowering Locus T 1 (RFT1) is the closest homologue of Heading date 3a (Hd3a), which promotes floral transition in short-day (SD) in rice. In SD, Hd3a RNAi plants delay flowering, but RFT1 RNAi plants do not. Double RFT1-Hd3a RNAi plants did not flower at 300 days in SD, suggesting that Hd3a and RFT1 are main SD regulators of photoperiodic flowering in rice. In LD, RFT1 RNAi plants delay flowering, but Hd3a RNAi plants do not. In RFT1 RNAi plants, expression of OsMADS14, an orthologue of Arabidopsis AP1, was suppressed in LD, suggesting that RFT1 is a floral activator and it acts upstream of OsMADS14 in LD. These results suggest that Hd3a, a floral activator in SD and RFT1, a floral activator in LD regulate photoperiodic flowering in rice.
