Rice ONAC016 promotes leaf senescence through abscisic acid signaling pathway involving OsNAP

Senescence-induced NAC(senNAC)TFs play a crucial role in senescence during the final stage of leaf development.In this study,we identified a rice senNAC,ONAC016,which functions as a positive regulator of leaf senescence.The expression of ONAC016 increased rapidly in rice leaves during the progression of dark-induced and natural senescence.The onac016-1 knockout mutant showed a delayed leaf yellowing phenotype,whereas the overexpression of ONAC016 accelerated leaf senescence.Notably,ONAC016 expression was upregulated by abscisic acid(ABA),and thus detached leaves of the onac016-1 mutant remained green much longer under ABA treatment.Quantitative RT-PCR analysis showed that ONAC016 upregulates the genes associated with chlorophyll degradation,senescence,and ABA signaling.Yeast one-hybrid and dual-luciferase assays revealed that ONAC016 binds directly to the promoter regions of OsNAP,a key gene involved in chlorophyll degradation and ABA-induced senescence.Taken together,these results suggest that ONAC016 plays an important role in promoting leaf senescence through the ABA signaling pathway involving OsNAP.