College of Biology, Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan Engineering and Technology Research Center of Hybrid Rapeseed, Hunan University, Changsha 410082, China; Shenzhen Institute, Hunan University, Shenzhen 518057, China.
College of Biology, Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan Engineering and Technology Research Center of Hybrid Rapeseed, Hunan University, Changsha 410082, China.
Plant Commun. 2024 Jul 8;5(7):100922. doi: 10.1016/j.xplc.2024.100922. Epub 2024 Apr 14.
Proper timing of flowering under different environmental conditions is critical for plant propagation. Light quality is a pivotal environmental cue that plays a critical role in flowering regulation. Plants tend to flower late under light with a high red (R)/far-red (FR) light ratio but early under light with a low R/FR light ratio. However, how plants fine-tune flowering in response to changes in light quality is not well understood. Here, we demonstrate that F-box of Flowering 2 (FOF2), an autonomous pathway-related regulator, physically interacts with VASCULAR PLANT ONE-ZINC FINGER 1 and 2 (VOZ1 and VOZ2), which are direct downstream factors of the R/FR light receptor phytochrome B (PHYB). We show that PHYB physically interacts with FOF2, mediates stabilization of the FOF2 protein under FR light and end-of-day FR light, and enhances FOF2 binding to VOZ2, which leads to degradation of VOZ2 by SCF E3 ligase. By contrast, PHYB mediates degradation of FOF2 protein under R light and end-of-day R light. Genetic interaction studies demonstrated that FOF2 functions downstream of PHYB to promote FLC expression and inhibit flowering under both high R/FR light and simulated shade conditions, processes that are partially dependent on VOZ proteins. Taken together, our findings suggest a novel mechanism whereby plants fine-tune flowering time through a PHYB-FOF2-VOZ2 module that modulates FLC expression in response to changes in light quality.
在不同的环境条件下适时开花对植物的繁殖至关重要。光质是一种关键的环境线索，在开花调控中起着关键作用。植物在红光（R）/远红光（FR）比值高的光照下倾向于晚开花，但在 R/FR 比值低的光照下早开花。然而，植物如何微调开花以响应光质的变化还不是很清楚。在这里，我们证明了开花 2 型的 F-box（FOF2）作为一个自主途径相关的调节因子，与 VASCULAR PLANT ONE-ZINC FINGER 1 和 2（VOZ1 和 VOZ2）物理相互作用，后者是 R/FR 光受体光敏色素 B（PHYB）的直接下游因子。我们表明 PHYB 与 FOF2 物理相互作用，介导 FR 光和黄昏 FR 光下 FOF2 蛋白的稳定，并增强 FOF2 与 VOZ2 的结合，从而导致 VOZ2 被 SCF E3 连接酶降解。相比之下，PHYB 在 R 光和黄昏 R 光下介导 FOF2 蛋白的降解。遗传相互作用研究表明，FOF2 作为 PHYB 的下游因子发挥作用，促进 FLC 表达，抑制高 R/FR 光和模拟遮荫条件下的开花，这些过程部分依赖于 VOZ 蛋白。总之，我们的研究结果表明了一种新的机制，植物通过 PHYB-FOF2-VOZ2 模块来微调开花时间，该模块通过调节 FLC 表达来响应光质的变化。
