Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
New Phytol. 2020 Feb;225(4):1593-1605. doi: 10.1111/nph.16236. Epub 2019 Nov 8.
Environmental light signal and GAs synergistically regulate seed dormancy and germination. The phytochrome B (phyB) photoreceptor regulates expression of the REVEILLE1 (RVE1) transcription factor, which directly inhibits GIBBERELLIN 3-OXIDASE2 transcription, suppressing GA biosynthesis. However, whether phyB-RVE1 coordinates with GA signaling in controlling seed dormancy and germination remains unknown. Here, we demonstrate that RVE1 regulation of seed dormancy and germination requires a DELLA repressor, REPRESSOR OF GA-LIKE2 (RGL2), in Arabidopsis thaliana. RVE1 interacts with both RGL2 and its E3 ubiquitin ligase SLEEPY1 (SLY1) and promotes RGL2 stability by restraining the RGL2-SLY1 interaction. Furthermore, RVE1 and RGL2 synergistically regulate global transcriptome changes; RGL2 enhances the DNA-binding capacity and transcriptional activity of RVE1 in regulating downstream gene expression. Moreover, RGL2 expression is repressed by phyB. Our study reveals a novel regulatory mechanism in which the RVE1-RGL2 module coordinately controls seed dormancy and germination by integrating light perception, GA metabolism and GA signaling pathways.
环境光信号与 GAs 协同调控种子休眠和萌发。光敏色素 B（phyB）光受体调节 REVEILLE1（RVE1）转录因子的表达，其直接抑制赤霉素 3-氧化酶 2（GA3ox2）转录，从而抑制 GA 生物合成。然而，phyB-RVE1 是否在调控种子休眠和萌发方面与 GA 信号协同作用尚不清楚。在这里，我们证明 RVE1 对种子休眠和萌发的调控需要拟南芥中的 DELLA 抑制物 REPRESSOR OF GA-LIKE2（RGL2）。RVE1 与 RGL2 及其 E3 泛素连接酶 SLEEPY1（SLY1）相互作用，并通过抑制 RGL2-SLY1 相互作用来促进 RGL2 的稳定性。此外，RVE1 和 RGL2 协同调控全局转录组变化；RGL2 增强了 RVE1 调节下游基因表达的 DNA 结合能力和转录活性。此外，phyB 抑制 RGL2 的表达。我们的研究揭示了一种新的调控机制，即 RVE1-RGL2 模块通过整合光感知、GA 代谢和 GA 信号通路协同调控种子休眠和萌发。
