The Ry(sto) immune receptor recognises a broadly conserved feature of potyviral coat proteins.

Knowledge of the immune mechanisms responsible for viral recognition is critical for understanding durable disease resistance and successful crop protection. We determined how potato virus Y (PVY) coat protein (CP) is recognised by Ry(sto) , a TNL immune receptor. We applied structural modelling, site-directed mutagenesis, transient overexpression, co-immunoprecipitation, infection assays and physiological cell death marker measurements to investigate the mechanism of Ry(sto) -CP interaction. Ry(sto) associates directly with PVY CP in planta that is conditioned by the presence of a CP central 149 amino acids domain. Each deletion that affects the CP core region impairs the ability of Ry(sto) to trigger defence. Point mutations in the amino acid residues Ser(125) , Arg(157) , and Asp(201) of the conserved RNA-binding pocket of potyviral CP reduce or abolish Ry(sto) binding and Ry(sto) -dependent responses, demonstrating that appropriate folding of the CP core is crucial for Ry(sto) -mediated recognition. Ry(sto) recognises the CPs of at least 10 crop-damaging viruses that share a similar core region. It confers immunity to plum pox virus and turnip mosaic virus in both Solanaceae and Brassicaceae systems, demonstrating potential utility in engineering virus resistance in various crops. Our findings shed new light on how R proteins detect different viruses by sensing conserved structural patterns.