The wheat leaf rust resistance gene Lrk10 maps to barley chromosome 1HS

A cDNA clone corresponding to the wheat Lrk10 leaf rust gene, which encodes a receptor-like serine-threonine kinase and maps to wheat chromosome 1AS, was used as probe for RFLP mapping in barley. The observed polymorphisms with three restriction enzymes were mapped to 1HS of barley and turned out to be linked with Mla12, which determines powdery mildew resistance. This barley 1HS region also contains other resistance genes against powdery mildew, leaf and stripe rust which suggests some combined organisation of the genes underlying the host defence mechanisms. Four different primers, corresponding to different parts of the Lrk10 gene sequence, have been designed. The STSs obtained with two such primer combinations map to the same locus as the cDNA probe itself, thus representing efficient markers of the target gene.