The XA48–OsVOZ1 immune module: from asymmetric domestication to PTI–ETI pyramiding for yield-penalty-free resistance

Abstract To advance modern crop breeding by de novo domestication, Hui Lin and colleagues recently characterized an immune module in rice subspecies Oryza sativa subsp. indica ( OSI ) and O. sativa subsp . japonica ( OSJ ). The module involves rice resistance protein XA48 and the downstream transcription factor OsVOZ1. Carrying an alanine (A) to serine (S) variation, OsVOZ1 functions redundantly with OsVOZ2 in suppressing rice resistance to bacterial blight, a worldwide significant crop disease caused by Xanthomonas oryzae pv. oryzae ( Xoo ). XA48, identified in an OSI cultivar, recognizes the Xoo effector XopG, confers resistance and susceptibility to XopG-harboring Xoo strains from Northeast and South Asia, respectively, and activates effector-triggered immunity (ETI) by degrading Os VOZ1/2. In resistance spectra, this ETI complements pattern-triggered immunity (PTI) mediated by XA21, a resistance protein previously identified in wild rice. The Xa48–OsVOZ1 module has undergone asymmetric selection: Xa48 is retained in OSI and lost in OSJ , whereas OSI retains both OsVOZ1 A/S alleles and OSJ retains only OsVOZ1 A . Although restoring XA48 to OSJ severely reduces grain yield, integrating XA48/ETI and XA21/PTI into modern OSI and OSJ cultivars rebuilds broad-spectrum resistance without a yield penalty, opening an avenue toward modern crop breeding using immunity sources from wild rice.