Pm37 as a susceptible Sr22 allele confers resistance to wheat powdery mildew and leaf rust.

Abstract

Wheat relatives harbour abundant variations that can be used for genetic improvement against diseases through complex domestication processes. Here, we report the isolation of the powdery mildew resistance gene Pm37 in common wheat through a strategy integrating map-based cloning, PacBio SMRT long-read genome sequencing, mutagenesis, barley stripe mosaic virus-induced gene silencing and stable transformation. Pm37 encodes a coiled-coil nucleotide-binding site leucine-rich repeat (CC-NBS-LRR) receptor. The cell death-inducing activity of PM37 in Nicotiana benthamiana is mainly mediated by its CC domain. De novo genome sequencing and haplotype analysis reveal that Pm37 may be derived from Triticum monococcum, and transferred into common wheat through T. timopheevii. Interestingly, Pm37 is a susceptible allele of the stem rust resistance locus Sr22, and also confers moderate resistance to leaf rust. Our findings identify a gene characterized by allelic variation-driven functional divergence in response to different wheat diseases.