College of Biology, Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan Hybrid Rape Engineering and Technology Research Center, 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 Hybrid Rape Engineering and Technology Research Center, Hunan University, Changsha 410082, China.
Mol Plant. 2021 Aug 2;14(8):1328-1342. doi: 10.1016/j.molp.2021.05.011. Epub 2021 May 7.
Light is a critical environmental cue that regulates a variety of diverse plant developmental processes. Cryptochrome 1 (CRY1) is the major photoreceptor that mediates blue light-dependent photomorphogenic responses such as the inhibition of hypocotyl elongation. Gibberellin (GA) participates in the repression of photomorphogenesis and promotes hypocotyl elongation. However, the antagonistic interaction between blue light and GA is not well understood. Here, we report that blue light represses GA-induced degradation of the DELLA proteins (DELLAs), which are key negative regulators in the GA signaling pathway, via CRY1, thereby inhibiting the GA response during hypocotyl elongation. Both in vitro and in vivo biochemical analyses demonstrated that CRY1 physically interacts with GA receptors-GA-INSENSITIVE DWARF 1 proteins (GID1s)-and DELLAs in a blue light-dependent manner. Furthermore, we showed that CRY1 inhibits the association between GID1s and DELLAs. Genetically, CRY1 antagonizes the function of GID1s to repress the expression of cell elongation-related genes and thus hypocotyl elongation. Taken together, our findings demonstrate that CRY1 coordinates blue light and GA signaling for plant photomorphogenesis by stabilizing DELLAs through the binding and inactivation of GID1s, providing new insights into the mechanism by which blue light antagonizes the function of GA in photomorphogenesis.
光是一种关键的环境线索，调节着多种不同的植物发育过程。隐花色素 1（CRY1）是介导蓝光依赖的光形态建成反应的主要光受体，如抑制下胚轴伸长。赤霉素（GA）参与抑制光形态建成并促进下胚轴伸长。然而，蓝光和 GA 之间的拮抗相互作用尚不清楚。在这里，我们报告说，蓝光通过 CRY1 抑制 GA 诱导的 DELLA 蛋白（DELLAs）降解，DELLAs 是 GA 信号通路中的关键负调控因子，从而抑制下胚轴伸长过程中的 GA 反应。体外和体内生化分析表明，CRY1 以蓝光依赖的方式与 GA 受体-GA 不敏感矮化蛋白 1 蛋白（GID1s）和 DELLAs 发生物理相互作用。此外，我们表明 CRY1 抑制 GID1s 和 DELLAs 之间的结合。在遗传上，CRY1 拮抗 GID1s 的功能，通过结合和失活 GID1s 来抑制与细胞伸长相关基因的表达，从而抑制下胚轴伸长。总之，我们的研究结果表明，CRY1 通过结合和失活 GID1s 来稳定 DELLAs，从而协调蓝光和 GA 信号通路，促进植物光形态建成，为蓝光在光形态建成中拮抗 GA 功能的机制提供了新的见解。
