Abstract
Key message: Wheat- Aegilops speltoides recombinants carrying stem rust resistance genes Sr32 and SrAes1t effective against Ug99 and PCR markers for marker-assisted selection. Wild relatives of wheat are important resources for new rust resistance genes but underutilized because the valuable resistances are often linked to negative traits that prevent deployment of these genes in commercial wheats. Here, we report ph1b-induced recombinants with reduced alien chromatin derived from E.R. Sears' wheat-Aegilops speltoides 2D-2S#1 translocation line C82.2, which carries the widely effective stem rust resistance gene Sr32. Infection type 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 2S#1. Recombinants with substantially shortened alien chromatin were produced for both genes, which confer resistance to stem rust races in the TTKSK (Ug99) lineage and representative races of all Australian stem rust lineages. Selected recombinants were back crossed into adapted Australian cultivars and PCR markers were developed to facilitate the incorporation of these genes into future wheat varieties. Our recombinants and those from several other labs now show that Sr32, Sr39, and SrAes7t on the short arm and Sr47 and SrAes1t on the long arm of 2S#1 form two linkage groups and at present no rust races are described that can distinguish these resistance specificities.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2943-2955 |
| Number of pages | 13 |
| Journal | Theoretical and Applied Genetics |
| Volume | 126 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 2013 |
| Externally published | Yes |
Bibliographical note
Funding Information:We thank the late Dr Paul Brennan, former Senior Wheat Breeder, Toowoomba, Australia, for initially suggesting Sr32-carrying germplasm as an objective for this research. We also thank Professor R.A. McIntosh (University of Sydney) for kindly providing the wheat-Aegilops speltoides translocation lines carrying Sr32 and critically reviewing the manuscript. We are thankful to Xiaodi Xia and Hanif Miah for providing excellent technical assistance and to T.T. The (University of Sydney) for producing some of the backcross materials. Research involving the isolation of the wheat–Ae. speltoides recombinants was funded by the Grains Research and Development Corporation of Australia through the Australian Cereal Rust Control Program and was previously associated with the CRC for Molecular Plant Breeding.
