F-box protein PeFKF1 promotes flowering by cooperating with PeID1 and PeHd1 in Phyllostachys edulis

Woody bamboo is a perennial flowering plant with a unique characteristic. Most woody bamboo species have no apparent signs before flowering, and large areas typically die after flowering, thus resulting in significant economic losses. However, most bamboo flowering gene functions and molecular mechanisms are still unclear. In this study, F-box protein FLAVIN-BINDING KELCH REPEAT F-BOX 1 (FKF1) was identified in Phyllostachys edulis (moso bamboo) and named PeFKF1. PeFKF1 exhibited a clear circadian rhythm and was highly expressed during the early flowering stage of moso bamboo. Overexpression of PeFKF1 caused early flowering in rice by increasing the expression of Hd1, RID1, Ehd1 and Hd3a. The expression pattern of RID1 homologous gene (PeID1) in bamboo was similar to that of PeFKF1 during both flowering and photoperiod regulation. In addition, PeFKF1 could bind to the promoter of PeID1 and enhance its expression. Furthermore, PeFKF1 could interact with PeID1 and PeHd1 proteins, creating protein complexes with them. Hence, PeFKF1 could recruit PeID1 and PeHd1 and enhance the expression of PeID1, thereby promoting flowering in moso bamboo. This study provides new insights into the mechanism of bamboo flowering.