Abstract
Rice Flowering Locus T 1 (RFT1) is the closest homologue of Heading date 3a (Hd3a) gene, which promotes floral transition in short-day (SD) of rice. Double RFT1-Hd3a RNAi plants did not flower even at 300 days after sowing, suggesting that RFT1 is a novel regulator of photoperiodic flowering in rice. RFT1 expression was very low in wild-type plants, however, in Hd3a RNAi plants, a marked increase of RFT1 expression was found at the late stage and complemented the lack of Hd3a expression, promoting flowering. Furthermore, we found that changes in chromatin modification at the 5'UTR of RFT1 locus were observed when RFT1 expression was increased in Hd3a RNAi plants. These results indicate that photoperiodic flowering of rice in SD is regulated by the intergenic communication between Hd3a and RFT1 through chromatin modifications.
