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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Publications at this Location » Publication #336379

Title: Mapping of leaf rust resistance genes and molecular characterization of the 2NS/2AS translocation in the wheat cultivar 'Jagger'

item XUE, SHULIN - Oklahoma State University
item Kolmer, James
item WANG, SHUWEN - The Land Institute
item YAN, LIULING - Oklahoma State University

Submitted to: G3, Genes/Genomes/Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2018
Publication Date: 4/19/2018
Citation: Xue, S., Kolmer, J.A., Wang, S., Yan, L. 2018. Mapping of leaf rust resistance genes and molecular characterization of the 2NS/2AS translocation in the wheat cultivar 'Jagger'. G3, Genes/Genomes/Genetics.

Interpretive Summary: Jagger is a wheat cultivar grown in the southern Great Plains of the United States. This cultivar has resistance to the disease leaf rust, caused by the fungus Puccinia triticina. Jagger has a segment of a chromosome from a wild grass relative of wheat. On this segment a gene that gives resistance to leaf rust was located using molecular markers. This gene was located in the same segment of chromosome as the gene Lr17a that is found in regular wheat cultivars without the wild grass chromosome segment. This gene is likely a variant or allele of Lr17. This information can be used by wheat breeders and plant pathologists to develop leaf rust resistant wheat cultivars.

Technical Abstract: Winter wheat cultivar 'Jagger' was recently found to have an alien chromosomal segment 'VPM1' that should carry Lr37, a gene conferring resistance against leaf rust caused by Puccinia triticina, and this cultivar was also reported to have the wheat gene Lr17 against leaf rust. Both Lr17 and Lr37 were reported to reside on the short arm of chromosome 2A in wheat. In this study, two fungal pathogen races, THBJG and BBBDB that are avirulent to Lr17 at the seedling stage, were used to precisely map this gene by inoculating the population of Jagger × '2174' recombinant inbred lines. As a result, a major quantitative trait locus (QTL) for THBJG and BBBDB was coincidently mapped to chromosome 2AS, and the QTL alone accounted for 62.2 % of total phenotypic variation in reaction to THBJG, and 64.4 % to BBBDB. However, it was found that Jagger did not have the wheat Lr17 but had an orthologous Lr17N present in the VPM1 segment that conferred resistance against both THBJG and BBBDB. Further analysis of IWGSC Chinese Spring genome sequences showed that the VPM1 segment translocated into a region starting from the telomere of 2AS and its physical length was approximately 24 Mb. The Lr17N gene was delimited to a genomic region of 4.4 Mb, where several candidate genes encoding RGA, WRKY and LRR conserved domains were identified. In addition, Jagger was found to have a resistant allele at another three minor QTLs that were mapped associated with reaction to both THBJG and BBBDB.