renjie.chen@kaust.edu.sa

Tandem kinases (TKs) have recently emerged as crucial determinants of resistance in wheat and barley against various pathogens. In this study, we investigated the mechanism of Sr62TK, which imparts broad-spectrum resistance to stem rust. We identified Sr62NLR, an NLR-encoding gene, as a genetic interactor of Sr62TK and demonstrated its requirement for Sr62TK function.

Additionally, we cloned the corresponding fungal AvrSr62 effector from stem rust isolate Pgt21-0 and showed its interaction with Sr62TK. Alphafold predictions suggest that a β-finger in the N-terminal kinase domain of Sr62TK contributes to Sr62TK homodimerization and AvrSr62 binding. We found that different orthologous NLR genes from wheat can support the Sr62TK-mediated immune response, both in wheat protoplasts and in N. benthamiana leaves, upon detection of the AvrSr62 effector. These insights enhance our understanding of the mechanisms underlying TK-mediated resistance, paving the way for targeted crop protection strategies.