FLAVIN-BINDING KELCH REPEAT F-BOX 1 (FKF1) encodes an F-box protein that regulates photoperiod flowering in Arabidopsis under long-day conditions (LDs). Gibberellin (GA) is also important for regulating flowering under LDs. However, how FKF1 and the GA pathway work in concert in regulating flowering is not fully understood. Here, we showed that the mutation of FKF1 could cause accumulation of DELLA proteins, which are crucial repressors in GA signaling pathway, thereby reducing plant sensitivity to GA in flowering. Both in vitro and in vivo biochemical analyses demonstrated that FKF1 directly interacted with DELLA proteins. Furthermore, we showed that FKF1 promoted ubiquitination and degradation of DELLA proteins. Analysis of genetic data revealed that FKF1 acted partially through DELLAs to regulate flowering under LDs. In addition, DELLAs exerted a negative feedback on FKF1 expression. Collectively, these findings demonstrate that FKF1 promotes flowering partially by negatively regulating DELLA protein stability under LDs, and suggesting a potential mechanism linking the FKF1 to the GA signaling DELLA proteins.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.