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Title: Development of wheat-Aegilops speltoides recombinants and simple PCR-based markers for stem rust resistance genes on the 2S#1 chromosome

Author
item MAGO, ROHIT - Commonwealth Scientific And Industrial Research Organisation (CSIRO)
item VERLIN, DAWN - University Of Adelaide
item ZHANG, PENG - University Of Sydney
item BANSAL, URMIL - University Of Sydney
item BARIANA, HARBANS - University Of Sydney
item Jin, Yue
item ELLIS, JEFFREY - Commonwealth Scientific And Industrial Research Organisation (CSIRO)
item HOXHA, SAMI - University Of Sydney
item DUNDAS, IAN - University Of Adelaide

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/2013
Publication Date: 8/30/2013
Citation: Mago, R., Verlin, D., Zhang, P., Bansal, U., Bariana, H., Jin, Y., Ellis, J., Hoxha, S., Dundas, I. 2013. Development of wheat-Aegilops speltoides recombinants and simple PCR-based markers for stem rust resistance genes on the 2S#1 chromosome. Theoretical and Applied Genetics. 126:2943–2955.

Interpretive Summary: Stem rust, an important disease in wheat, is controlled primarily through the use of host resistance. Wild relatives of wheat are important, yet under utilized resources for new rust resistance genes, because linked negative traits often hinder deployment of these genes in commercial wheats. Here we report reduced alien chromatin recombinants derived from a wheat-Aegilops speltoides translocation line, which carries the widely effective stem rust resistance gene Sr32. Rust response assessments of the recombinants showed that the original translocation in fact carries two stem rust resistance genes, Sr32 on the short arm and a previously undescribed gene SrAes1t on the long arm of chromosome 2D. Recombinants with substantially shortened alien chromatin tagged with simple PCR-based markers were produced for both genes, which confer resistance to stem rust race TTKSK (Ug99). A marker linked to Sr47 carried on an independently derived translocation in a tetraploid background involving Ae. speltoides was also diagnostic for the SrAes1t gene. However, the allelic and resistance specificity relationships between SrAes1t and Sr47 are unclear. The PCR markers developed in the study will facilitate the incorporation of these genes into future wheat varieties. This research will help wheat breeders and geneticists in the utilization of this resistance to develop wheat varieties with improved stem rust resistance.

Technical Abstract: Wild relatives of wheat are important but underutilized resources for new rust resistance genes because linked negative traits often hinder deployment of these genes in commercial wheats. Here we report reduced alien chromatin recombinants derived from E.R. Sears wheat-Aegilops speltoides translocation line C82.2, which carries the widely effective stem rust resistance gene Sr32. Rust response assessments of the recombinants showed that the original translocation in fact carries two stem rust resistance genes, Sr32 on the short arm and a previously undescribed gene SrAes1t on the long arm of chromosome 2D. Recombinants with substantially shortened alien chromatin tagged with simple PCR-based markers were produced for both genes, which confer resistance to stem rust race TTKSK (Ug99). A marker linked to Sr47 carried on an independently derived translocation in a tetraploid background involving Ae. speltoides was also diagnostic for the SrAes1t gene. However, the allelic and resistance specificity relationships between SrAes1t and Sr47 are unclear. The PCR markers developed in the study will facilitate the incorporation of these genes into future wheat varieties.