A wheat tandem kinase and NLR pair confers resistance to multiple fungal pathogens.

Abstract

Tandem kinase proteins underlie the innate immune systems of cereal plants, but how they initiate plant immune responses remains unclear. This report identifies wheat protein wheat tandem NBD 1 (WTN1), a noncanonical nucleotide-binding leucine-rich repeat (NLR) receptor featuring tandem nucleotide binding adaptor shared by APAF-1, plant R proteins, and CED-4 (NB-ARC) domains, required for WTK3-mediated disease resistance. Both WTK3 and its allelic variant Rwt4-known for conferring resistance to wheat powdery mildew and blast, respectively-are capable of recognizing the blast effector PWT4. They activate WTN1 to form calcium-permeable channels, akin to ZAR1 and Sr35. Thus, tandem kinase proteins and their associated NLRs operate as "sensor-executor" pairs against fungal pathogens. Additionally, evolutionary analyses reveal a coevolutionary trajectory of the tandem kinase-NLR module, highlighting their cooperative role in triggering plant immunity.