Wang Qibin, Liu Meiling, Quan Shuxuan, Shi Qingbiao, Tian Tian, Zhang Haisen, Wang Haiyang, Li Gang
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China.
State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, School of Life Sciences, South China Agricultural University, Guangzhou, China.
Plant Cell Environ. 2023 May;46(5):1582-1595. doi: 10.1111/pce.14554. Epub 2023 Feb 14.
Senescence is the final stage of leaf development, limits and dictates the longevity of leaf. This stage is strictly controlled by internal developmental age signals and external environmental signals. However, the underlying mechanisms by which various signals integrating together to regulate leaf senescence remain largely unknown. Here, we show that the light signalling protein FAR-RED ELONGATED HYPOCOTYL3 (FHY3) directly represses the transcription of PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and NON-YELLOWING1/STAY-GREEN1 (NYE1/SGR1), two key regulators of senescence, thus preventing chlorophyll degradation and extending the leaf longevity in Arabidopsis thaliana. Disrupting either PIF4 or NYE1 function completely rescued the early leaf senescence of fhy3-4 mutant. Interestingly, we found that FHY3 competes with PIF4 to bind to the G-box cis-element in NYE1 promoter, subsequently preventing the transcriptional activation of this gene by PIF4. Moreover, FHY3 transcript levels gradually increased in senescent leaves, which consist with disrupting FHY3 function accelerated chlorophyll degradation and shorted the leaf longevity. All these findings reveal that FHY3 is a master regulator that participates in multiple signalling pathways to increase leaf longevity. In addition, our study shed light on the dynamic regulatory mechanisms by which plants integrate light signalling and internal developmental cues to control leaf senescence and longevity.
衰老作为叶片发育的最后阶段，限制并决定了叶片的寿命。这一阶段受到内部发育年龄信号和外部环境信号的严格调控。然而，各种信号整合在一起调控叶片衰老的潜在机制仍不清楚。在此，我们发现光信号蛋白远红光伸长下胚轴3（FHY3）直接抑制衰老的两个关键调节因子——光敏色素相互作用因子4（PIF4）和非黄化1/保持绿色1（NYE1/SGR1）的转录，从而防止叶绿素降解并延长拟南芥叶片的寿命。破坏PIF4或NYE1的功能均可完全挽救fhy3-4突变体的早期叶片衰老。有趣的是，我们发现FHY3与PIF4竞争结合NYE1启动子中的G-box顺式元件，进而阻止PIF4对该基因的转录激活。此外，FHY3转录水平在衰老叶片中逐渐升高，这与破坏FHY3功能会加速叶绿素降解并缩短叶片寿命一致。所有这些发现表明，FHY3是一个参与多种信号通路以增加叶片寿命的主要调节因子。此外，我们的研究揭示了植物整合光信号和内部发育线索以控制叶片衰老和寿命的动态调控机制。
