High-resolution mapping and mutation analysis separate the rust resistance genes Sr31, Lr26 and Yr9 on the short arm of rye chromosome 1
- 734 Downloads
The stem, leaf and stripe rust resistance genes Sr31, Lr26 and Yr9, located on the short arm of rye chromosome 1, have been widely used in wheat by means of wheat-rye translocation chromosomes. Previous studies have suggested that these resistance specificities are encoded by either closely-linked genes, or by a single gene capable of recognizing all three rust species. To investigate these issues, two 1BL·1RS wheat lines, one with and one without Sr31, Lr26 and Yr9, were used as parents for a high-resolution F2 mapping family. Thirty-six recombinants were identified between two PCR markers 2.3 cM apart that flanked the resistance locus. In one recombinant, Lr26 was separated from Sr31 and Yr9. Mutation studies recovered mutants that separated all three rust resistance genes. Thus, together, the recombination and mutation studies suggest that Sr31, Lr26 and Yr9 are separate closely-linked genes. An additional 16 DNA markers were mapped in this region. Multiple RFLP markers, identified using part of the barley Mla powdery mildew resistance gene as probe, co-segregated with Sr31 and Yr9. One deletion mutant that had lost Sr31, Lr26 and Yr9 retained all Mla markers, suggesting that the family of genes on 1RS identified by the Mla probe does not contain the Sr31, Lr26 or Yr9 genes. The genetic stocks and DNA markers generated from this study should facilitate the future cloning of Sr31, Lr26 and Yr9.
KeywordsAmplify Fragment Length Polymorphism Leaf Rust Rust Resistance Amplify Fragment Length Polymorphism Marker Rust Resistance Gene
We thank Dr. K.W. Shepherd, Waite Campus, University of Adelaide, Australia for providing the ‘King II’ derivative line. We acknowledge excellent technical assistance provided by Luch Hac, Pat Atkinson, Xiaodi Xia, Kim Newell and Cassie Wesley. This project (CSP0017) is supported by financial assistance from the Grains Research and Development Corporation and was undertaken as part of The Australian Cereal Rust Control Program.
- Adhikari KN (1996) Genetic studies of stem rust resistance in oat and trititicale. PhD Thesis, The University of Sydney, AustraliaGoogle Scholar
- Peng JH, Zadeh H, Lazo GR, Gustafson JP, Chao S, Anderson OD, Qi LL, Echalier B, Gill BS, Dilbirligi M, Sandhu D, Gill KS, Greene RA, Sorrells ME, Akhunov ED, Dvorak J, Linkiewicz AM, Dubcovsky J, Hossain KG, Kalavacharla V, Kianian SF, Mahmoud AA, Miftahudin, Conley EJ, Anderson JA, Pathan MS, Nguyen HT, McGuire PE, Qualset CO, Lapitan NL (2004) Chromosome bin map of expressed sequence tags in homoeologous group 1 of hexaploid wheat and homoeology with rice and Arabidopsis. Genetics 168:609–623CrossRefPubMedPubMedCentralGoogle Scholar
- Rajaram S, Mann CHE, Ortiz-Ferrara G, Mujeb-Kazi A (1983) Adaptation, stability and high yield potential of certain 1B/1R CIMMYT wheats. In: Sakamoto S (ed) Proceedings of the 6th International Wheat Genet Symposium, Kyoto, Japan, pp 613–621Google Scholar
- Wei F, Gobelman-Werner K, Morroll SM, Kurth J, Mao L, Wing R, Leister D, Schulze-Lefert P, Wise RP (1999) The Mla (Powdery Mildew) resistance cluster is associated with three NBS-LRR gene families and suppressed recombination within a 240 kb DNA interval on chromosome 5S (1HS) of barley. Genetics 153:1929–1948PubMedPubMedCentralGoogle Scholar
- Zeller FJ (1973) 1B/1R wheat-rye chromosome substitutions and translocations. In: Sears ER, Sears LMS (eds) Proceedings of the 4th International Wheat Genet Symposium, Columbia, Missouri, USA, pp 209–221Google Scholar