Septoria tritici blotch resistance gene Stb15 encodes a lectin receptor-like kinase

Abstract

Septoria tritici blotch (STB), caused by the Dothideomycete fungus Zymoseptoria tritici, is one of the most damaging diseases of bread wheat (Triticum aestivum)¹ and the target of costly fungicide applications². In line with the fungus's apoplastic lifestyle, STB resistance genes isolated to date encode receptor-like kinases (RLKs) including a wall-associated kinase (Stb6) and a cysteine-rich kinase (Stb16q)^3,4. Here we used genome-wide association studies on a diverse panel of 300 whole-genome shotgun-sequenced wheat landraces (WatSeq consortium⁵) to identify a 99-kb region containing six candidates for the Stb15 resistance gene. Mutagenesis and transgenesis confirmed a gene encoding an intronless G-type lectin RLK as Stb15. The characterization of Stb15 exemplifies the unexpected diversity of RLKs conferring Z. tritici resistance in wheat.