摘要Leaves play a crucial role in the growth and development of rice(Oryza sativa)as sites for the production of photosynthesis.Early leaf senescence leads to substantial drops in rice yields.Whether and how DNA methylation reg-ulates gene expression and affects leaf sen-escence remains elusive.Here,we demonstrate that mutations in rice ARGONAUTE 2(OsAGO2)lead to premature leaf senescence,with chlor-oplasts in Osago2 having lower chlorophyll content and an abnormal thylakoid structure compared with those from wild-type plants.We show that OsAGO2 associates with a 24-nt mi-croRNA and binds to the promoter region of OsNAC300,which causes DNA methylation and suppressed expression of OsNAC300.Overexpressing OsNAC300 causes the similar premature leaf senescence as Osago2 mutants and knocking out OsNAC300 in the Osago2 mutant background suppresses the early senescence of Osago2 mutants.Based on yeast one-hybrid,dual-luciferase,and electro-phoresis mobility shift assays,we propose that OsNAC300 directly regulates trans-cription of the key rice aging gene NAC-like,activated by APETALA3/PISTILLATA(OsNAP)to control leaf senescence.Our results unravel a previously unknown epigenetic regulatory mechanism underlying leaf senescence in which OsAGO2-OsNAC300-OsNAP acts as a key regulatory module of leaf senescence to maintain leaf function.