The NAP transcription factor: An integrative node for environmental and developmental signals in plant senescence

Organ senescence is a pivotal developmental transition that is finely tuned by developmental age and environmental cues. The NAC transcription factor NAP acts as a central integrator of these signals, translating them into the coordinated execution of senescence across reproductive and vegetative organs. This review focuses on its upstream regulation and downstream regulatory network in leaf senescence. We first summarize how developmental, hormonal, and environmental signals converge on NAP through specific transcriptional, epigenetic, post-transcriptional, and post-translational mechanisms. We then describe how NAP executes the leaf senescence program by directly activating a suite of effector genes, forming self-reinforcing loops with abscisic acid, ethylene, and salicylic acid biosynthesis, promoting cytokinin degradation, and accelerating water loss through stomatal regulation. Beyond leaves, NAP also governs senescence in ovules, siliques, and petals. Comparative analyses across monocots and eudicots reveal deep conservation of NAP function in senescence regulation but lineage-specific divergence in stress responses. Finally, we highlight key bottlenecks and emerging opportunities for translating NAP research into crop improvement. Together, these insights position NAP as a conserved regulatory hub for organ senescence and provide a framework for fine-tuning senescence timing to improve crop yield and resilience.