Welwitschia leaf senescence is orchestrated via ERF113-ERF115-mediated antagonism between hormone signaling pathways

Phytohormone crosstalk is fundamental to plant development and adaptation. While the coordinated actions of different hormones are well recognized, the underlying molecular mechanisms in specific biological processes remain largely elusive. Here, we identified the WmERF113-WmERF115 module as a central hub that mediated jasmonic acid (JA)/abscisic acid (ABA)-gibberellins (GA) antagonism to regulate leaf senescence in Welwitschia, a desert plant with only two leaves that grow continuously over an exceptionally long lifespan. We revealed that the JA/ABA-inducible transcription factor (TF) WmERF113 directly activated senescence-associated genes (SAGs), promoting senescence and chlorophyll degradation, whereas the GA-responsive WmERF115 repressed the same targets to mitigate senescence. Notably, WmERF113 and WmERF115 physically interacted to form a heterodimer, mutually inhibiting each other's binding to target promoters. Furthermore, these two TFs acted as reciprocal trans-acting factors, repressing each other's expression through promoter cross-binding. This multiple-layer regulatory circuit ensured that leaf senescence of Welwitschia progressed in a temporally and spatially restricted manner. Our study provided an important conceptual framework in which phytohormone crosstalk was translated into TF antagonism for fine-tuning senescence, offering new insights into the adaptive strategies that enable plant survival in extreme environments.