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A mutagenesis-derived broad-spectrum disease resistance locus in wheat.

Campbell, Jackie, Zhang, Hongtao, Giroux, Michael J., Feiz, Leila, Jin, Yue, Wang, Meinan, Chen, Xianming, Huang, Li
Theoretical and applied genetics 2012 v.125 pp. 391
Erysiphe graminis f. sp. tritici, Puccinia graminis, Puccinia recondita, Puccinia striiformis, Triticum aestivum, chromosome mapping, cultivars, defense mechanisms, disease resistance, gene expression, genes, incomplete dominance, leaf rust, loci, mature plants, mutagenesis, powdery mildew, seedlings, stem rust, wheat
Wheat leaf rust, stem rust, stripe rust, and powdery mildew caused by the fungal pathogens Puccinia triticina, P. graminis f. sp. tritici, P. striiformis f. sp. tritici, and Blumeria graminis f. sp. tritici, respectively, are destructive diseases of wheat worldwide. Breeding durable disease resistance cultivars rely largely on continually introgressing new resistance genes, especially the genes with diVerent defense mechanisms, into adapted varieties. Here, we describe a new resistance gene obtained by mutagenesis. The mutant, MNR220 (mutagenesis-derived new resistance), enhances resistance to three rusts and powdery mildew, with the characteristics of delayed disease development at the seedling stage and completed resistance at the adult plant stage. Genetic analysis demonstrated that the resistance in MNR220 is conferred by a single semidominant gene mapped on the short arm of chromosome 2B. Gene expression proWling of several pathogenesis-related genes indicated that MNR220 has an elevated and rapid pathogen-induced response. In addition to its potential use in breeding for resistance to multiple diseases, high-resolution mapping and cloning of the disease resistance locus in MNR220 may lead to a better understanding of the regulation of defense responses in wheat.