A wheat tandem kinase sensor activates an NLR helper to trigger immunity

Most plant resistance genes encode membrane-anchored receptor-like proteins or intracellular nucleotide-binding and leucine-rich repeat (NLR) receptors. In wheat and barley, tandem kinases (TKs) have emerged as a new class of resistance determinants. To understand the modus operandi of the wheat stem rust resistance protein Sr62 ^TK , we identified two genetic interactors— a host gene required for Sr62 ^TK function and the corresponding fungal AvrSr62 effector. We discovered that the SR62 locus consists of a digenic module encoding Sr62 ^TK and an NLR (Sr62 ^NLR ). AvrSr62 binds to the N-terminal kinase of Sr62 ^TK . This triggers displacement of the C-terminal kinase allowing it to recruit Sr62 ^NLR for activation of immune responses. Understanding the mechanism of this two-component resistance complex will help engineering and breeding for durable resistance.