Flowering time regulation by the CONSTANS-Like gene OsCOL10

Plant flowering at the appropriate time is critical for reproductive success and influenced by a series of environmental factors such as photoperiod and temperature. A number of genes involved in photoperiodic flowering of have been cloned and their roles in modulating expression of the flowering genes have been characterized to a certain extent. However, much less is known about the pathway in transmitting the day length response signal(s) to induce transition to reproductive growth. Recently, we characterized a constitutive flowering repressor OsCOL10 encoding for a member of the CONSTANS-like (COL) family. Through transgenic analysis, we have showed that OsCOL10 repress flowering by reducing expression of the FT-like genes RFT1 and Hd3a through Ehd1. Moreover, we also showed that OsCOL10 acts downstream of Ghd7, a key LD-specific flowering repressor by reducing expression of Ehd1. Collectively, our finding identifies OsCOL10 functioning as a flowering-time repressor that links between Ghd7 and Ehd1 in rice.