The OsIMP1-OsRLK5 immunopeptide-receptor pair confers bacterial and fungal disease resistance in rice

Plant receptor-like kinases (RLKs) often function as immune receptors for exogenous and endogenous elicitors. However, only a few immune ligand-receptor pairs have been identified in rice. In this study, we report that a rice gene encoding the secretory immunopeptide OsIMP1 is induced by pathogen-associated molecular patterns. The OsIMP1 peptide triggers immune responses and positively regulates rice disease resistance. Furthermore, the leucine-rich repeat receptor-like kinases OsRLK5 and OsRLK5-L and the somatic embryogenesis receptor-like kinase 2 (OsSERK2) are essential for OsIMP1-triggered immunity. OsRLK5 interacts with and phosphorylates OsSERK2. OsIMP1 directly binds to the extracellular domain of OsRLK5, positively regulating pattern-triggered immunity. Notably, overexpression of OsRLK5 confers increased resistance to bacterial and fungal diseases without a yield penalty in rice. Taken together, these results indicate that OsIMP1 and OsRLK5/OsRLK5-L form ligand-receptor pairs that confer rice resistance to multiple pathogens without incurring a growth penalty, providing important targets for developing rice varieties with broad-spectrum disease resistance.