Prime editing‐mediated correction of the endogenous <i>xa23</i> gene confers broad‐spectrum resistance to rice bacterial blight

Abstract Rice bacterial blight (BB), caused by Xanthomonas oryza e pv. oryzae ( Xoo ), is a devastating disease that threatens global rice ( Oryza sativa L.) production. Xoo delivers transcription activator‐like effectors that bind to effector binding elements in the promoters of host susceptibility ( S ) or resistance ( R ) genes, thereby triggering either disease development or defense responses. Xa23 is a broad‐spectrum R gene that confers strong BB resistance by recognizing the conserved EBE AvrXa23 in its promoter. In this study, we used an ScCas9‐based prime editing system to precisely correct three consecutive mutations in the dysfunctional EBE AvrXa23 sequence of the endogenous xa23 promoter in the susceptible japonica cultivar N9208. The engineered N9208(Xa23) line restored Xa23 inducibility upon Xoo infection and exhibited robust resistance against diverse Xoo strains without growth penalties. These results demonstrate a universal, precise, efficient, and biosafe strategy for engineering endogenous executor R genes and rapidly upgrading commercial rice cultivars for BB resistance without introducing exogenous DNA.