Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
University of the Chinese Academy of Sciences, Beijing 100049, China.
J Exp Bot. 2021 May 28;72(12):4577-4589. doi: 10.1093/jxb/erab158.
Leaf senescence can be triggered by multiple abiotic stresses including darkness, nutrient limitation, salinity, and drought. Recently, heatwaves have been occurring more frequently, and they dramatically affect plant growth and development. However, the underlying molecular networks of heat stress-induced leaf senescence remain largely uncharacterized. Here we showed that PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF5 proteins could efficiently promote heat stress-induced leaf senescence in Arabidopsis. Transcriptomic profiling analysis revealed that PIF4 and PIF5 are likely to function through multiple biological processes including hormone signaling pathways. Further, we characterized NAC019, SAG113, and IAA29 as direct transcriptional targets of PIF4 and PIF5. The transcription of NAC019, SAG113, and IAA29 changes significantly in daytime after heat treatment. In addition, we demonstrated that PIF4 and PIF5 proteins were accumulated during the recovery after heat treatment. Moreover, we showed that heat stress-induced leaf senescence is gated by the circadian clock, and plants might be more actively responsive to heat stress-induced senescence during the day. Taken together, our findings proposed important roles for PIF4 and PIF5 in mediating heat stress-induced leaf senescence, which may help to fully illustrate the molecular network of heat stress-induced leaf senescence in higher plants and facilitate the generation of heat stress-tolerant crops.
叶片衰老可由多种非生物胁迫触发，包括黑暗、养分限制、盐度和干旱。最近，热浪频繁发生，对植物的生长和发育产生了巨大影响。然而，热应激诱导叶片衰老的潜在分子网络在很大程度上仍未被阐明。在这里，我们发现 PHYTOCHROME INTERACTING FACTOR 4（PIF4）和 PIF5 蛋白可有效地促进拟南芥的热应激诱导叶片衰老。转录组分析显示，PIF4 和 PIF5 可能通过多种生物学过程发挥作用，包括激素信号通路。此外，我们鉴定了 NAC019、SAG113 和 IAA29 是 PIF4 和 PIF5 的直接转录靶标。NAC019、SAG113 和 IAA29 的转录在热处理后的白天发生显著变化。此外，我们证明 PIF4 和 PIF5 蛋白在热应激后恢复过程中积累。此外，我们表明，热应激诱导的叶片衰老受到生物钟的调控，并且植物在白天可能对热应激诱导的衰老更活跃。总之，我们的研究结果表明 PIF4 和 PIF5 在介导热应激诱导的叶片衰老中起重要作用，这可能有助于充分阐明高等植物中热应激诱导的叶片衰老的分子网络，并促进耐热作物的产生。
