He Reqing, Li Xinmei, Zhong Ming, Yan Jindong, Ji Ronghuan, Li Xu, Wang Qin, Wu Dan, Sun Mengsi, Tang Dongying, Lin Jianzhong, Li Hongyu, Liu Bin, Liu Hongtao, Liu Xuanming, Zhao Xiaoying, Lin Chentao
Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, 410082, China.
Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Plant J. 2017 Sep;91(5):788-801. doi: 10.1111/tpj.13607. Epub 2017 Jul 13.
Floral initiation is regulated by various genetic pathways in response to light, temperature, hormones and developmental status; however, the molecular mechanisms underlying the interactions between different genetic pathways are not fully understood. Here, we show that the photoresponsive gene FOF2 (F-box of flowering 2) negatively regulates flowering. FOF2 encodes a putative F-box protein that interacts specifically with ASK14, and its overexpression results in later flowering under both long-day and short-day photoperiods. Conversely, transgenic plants expressing the F-box domain deletion mutant of FOF2 (FOF2ΔF), or double loss of function mutant of FOF2 and FOL1 (FOF2-LIKE 1) present early flowering phenotypes. The late flowering phenotype of the FOF2 overexpression lines is suppressed by the flc-3 loss-of-function mutation. Furthermore, FOF2 mRNA expression is regulated by autonomous pathway gene FCA, and the repressive effect of FOF2 in flowering can be overcome by vernalization. Interestingly, FOF2 expression is regulated by light. The protein level of FOF2 accumulates in response to light, whereas it is degraded under dark conditions via the 26S proteasome pathway. Our findings suggest a possible mechanistic link between light conditions and the autonomous floral promotion pathway in Arabidopsis.
花的起始受多种遗传途径调控，以响应光照、温度、激素和发育状态；然而，不同遗传途径之间相互作用的分子机制尚未完全了解。在此，我们表明光响应基因FOF2（开花2的F-box）负向调控开花。FOF2编码一种假定的F-box蛋白，它与ASK14特异性相互作用，其过表达导致在长日照和短日照光周期下开花延迟。相反，表达FOF2的F-box结构域缺失突变体（FOF2ΔF）的转基因植物，或FOF2和FOL1（类FOF2 1）的双功能缺失突变体呈现早花表型。FOF2过表达系的晚花表型被flc-3功能缺失突变所抑制。此外，FOF2 mRNA表达受自主途径基因FCA调控，并且FOF2在开花中的抑制作用可通过春化作用克服。有趣的是，FOF2表达受光调控。FOF2的蛋白水平在光照下积累，而在黑暗条件下通过26S蛋白酶体途径降解。我们的研究结果表明拟南芥中光照条件与自主促进开花途径之间可能存在机制联系。
