Abstract Detail

Genetics Section

Kassa, Mulualem T. [1], Hiebert, Colin [2], You, Frank M. [2], Fobert, Pierre [1], Jordan, Mark C. [2], Andrew, Sharpe [3], Pozniak, Curtis J. [4], Fetch, Tom [2], Zegeye, Taye [2], Menzies, Jim [2], McCartney, Curt [2].

Genetic mapping and marker development for high-throughput marker-assisted breeding for Ug99 stem rust resistance gene SrCad/Sr42.

Wheat stem rust, caused by the fungus, Puccinia graminis f. sp. tritici (pgt) is a serious disease that causes huge economic loss across the world. The evolution and emergence of highly virulent pathogen races known as TTKSK (Ug99) and its variants had challenged and pose a great threat to global wheat production (Pretorius et al. 2000. The resistance gene SrCad, which confers Ug99 resistance, was mapped to chromosome 6DS (Hiebert et al., 2011). Similarly, the Ug99 stem rust resistance gene Sr42 was mapped to similar location as SrCad on chromosome 6DS (Ghazvini et al. 2012). Mapping suggests that SrCad could be Sr42 or allelic to Sr42 but the relationships of these two resistance genes is still not sufficiently resolved. A lack of polymorphic markers in the 6DS region has hampered the fine mapping of SrCad/Sr42. Moreover, lack of closely linked markers slowed the use of marker-assisted selection in breeding efforts of deploying SrCad/Sr42. The current study identified single nucleotide polymorphisms (SNP) markers that are tightly linked with SrCad/Sr42 resistance gene(s). The SNPs were converted to breeder-friendly Kompetitive Allele Specific PCR (KASP) assays and were mapped in two SrCad mapping populations consisting of an F6 derived recombinant inbred line (RIL) population of 384 lines and a doubled-haploid (DH) population with 345 lines. Similarly the SNPs were also mapped on an Sr42 mapping population with 267 DH lines respectively. The marker location and order on all maps are consistent and both SrCad and Sr42 were delineated within < 0.8 cM interval. A number of SNPs that are tightly linked (cosegregate) with SrCad/Sr42 were identified. Haplotype analysis on a panel of 72 diverse sets of wheat cultivars shows consistency between the markers and SrCad/Sr42 phenotype. The markers were cross-applicable for SrCad/Sr42 and can be useful for high throughput marker assisted selection and provide a starting point for map-based cloning of SrCad/Sr42.

1 - National Research Council Canada, ACRD, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
2 - Agriculture and Agri-Food Canada, Cereal research Centre, 101 Route 100, Morden, MB, R6M 1Y5, Canada
3 - National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
4 - University of Saskatchewan, Crop Development Centre/Department of Plant Sciences, 51 Campus Drive, , Saskatoon, SK, S7N 5A8, Canada

Keywords:
Stem rust
Ug99
SrCad
Sr42
linkage mapping.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PGN018
Abstract ID:1269
Candidate for Awards:None