Abstract
Rice is a short-day (SD) plant and promotes flowering by the expression of Hd3a (FT-L2) under SD condition. Ten Hd3a-like genes (FT-L1~11) are present in rice genome. However, their functions in flowering are not known because of the lack of their mutations. To examine the expression patterns of Hd3a-like gene family, we investigated their mRNA levels every 10 days until flowering. Six Hd3a-like genes were highly expressed at 35 days after sowing, which is most sensitive to the day-length under SD. Two types of RNAi constructs were designed; one was to specifically suppress the individual Hd3a-like genes and second was to simultaneously suppress multiple Hd3a-like genes. The transgenic rice, in which Hd3a mRNA was suppressed, flowered much later than the wild type. These results indicated that Hd3a promotes flowering under SD. We are currently investigating whether the other Hd3a-like genes are also involved in flowering.
