OsFY, a homolog of AtFY, encodes a protein that can interact with OsFCA-gamma in rice (Oryza sativa L.).

FCA and FY are flowering time related genes involved in the autonomous flowering pathway in Arabidopsis. FCA interacts with FY to regulate the alternative processing of FCA pre-mRNA. The FCA/FY interaction is also required for the regulation of FLC expression, a major floral repressor in Arabidopsis. However, it is not clear if the regulation of this autonomous flowering pathway is also present in monocot plants, such as rice. Recently, alternative RNA processing of OsFCA was observed in rice, which strongly suggested the existence of an autonomous flowering pathway in rice. In this work, we cloned the cDNA of the autonomous flowering pathway gene OsFY from rice. The predicted OsFY protein contained a conserved 7 WD-repeat region and at least two Pro-Pro-Leu-Pro motifs compared to Arabidopsis FY. The protein-protein interaction between OsFY and OsFCA-gamma, the key feature of their gene function, was also demonstrated using the yeast two-hybrid system. The GenBank database search provided evidence of expression for other autonomous pathway gene homologs in rice. These results indicate that the autonomous flowering pathway is present in monocots, and the regulation through FY and FCA interaction is conserved between monocots and dicots.