Phenotypic and genotypic description of Puccinia graminis f. sp. tritici race 2SA55 in South Africa
Race 2SA55 of the wheat stem rust pathogen, Puccinia graminis f. sp. tritici, was described for the first time during 2000 in South Africa. This race is of particular interest as it was the first local report of increased virulence towards barley cultivars by wheat stem rust. Using three original accessions of 2SA55 from the rust collection of the University of the Free State, nine single pustule isolates were established. Phenotyping of isolates to characterise 2SA55 according to the North American nomenclature system revealed variation in virulence for Sr9g on the tester lines Kubanka and Acme, which was not detected in the initial description of 2SA55. Seven isolates coded as BNGSC, which except for virulence on Sr9b resembled the initial avirulence/virulence description for 2SA55. The remaining two isolates with Sr9g virulence coded as BPGSC. The seedling infection types for the two 2SA55 derived races BNGSC and BPGSC on the Stakman differential set as well as on an extended set of Sr lines and 144 South African wheat cultivars and advanced breeding lines revealed no further distinction in reaction between them. Microsatellite analysis indicated that while race BN/PGSC shares phenotypic similarity with several of the South African non-Ug99 races, it was genetically distinct.
KeywordsStem rust Puccinia graminis f. sp. tritici Wheat Race description
The microsatellite analysis was funded by the National Research Foundation, SA (grant number 87692).
Compliance with ethical standards
We hereby declare that our submission is in compliance with the ethical responsibilities and standards of the EJPP as well as those of the University of the Free State.
Conflict of interest
The authors declare that they have no conflict of interest.
- Boshoff, W.H.P., Pretorius, Z.A., Van Niekerk, B.D., & Komen, J.S. (2002). First report of virulence in Puccinia graminis f. sp. tritici to wheat stem rust resistance genes Sr8b and Sr38 in South Africa. Plant Disease 86, 922.Google Scholar
- Excoffier, L., Laval, G., & Schneider, S. (2005). Arlequin ver. 3.0: An integrated software package for population genetics data analysis. Evolutionary Bioinformatics Online, 1, 47–50.Google Scholar
- Hart, D. L., & Clark, A. G. (1997). Principles of population genetics (3rd ed.). Sunderland: Sinauer Associates.Google Scholar
- Le Roux, J. (1989). Physiologic specialization of Puccinia graminis f. sp. tritici in South Africa during the period 1981-1985. Phytophylactica, 19, 456–472.Google Scholar
- Le Roux, J., & Rijkenberg, F. H. (1987). Occurrence and pathogenicity of Puccinia graminis f. sp. tritici with increased virulence for Sr24. Plant Disease, 71, 1115–1119.Google Scholar
- Lombard, B. (1986). Host–pathogen interactions involving wheat and Puccinia graminis f. sp. tritici in South Africa. PhD thesis, University of Stellenbosch, South Africa.Google Scholar
- Perrier, X., Flori, A., & Bonnot, F. (2003). Data analysis methods. In P. Hamon, M. Seguin, X. Perrier, & J. C. Glazmann (Eds.), Genetic diversity of cultured tropical plants (pp. 43–76). Enfield, UK: Science Publishers.Google Scholar
- Pretorius, Z. A., Singh, R. P., Wagoire, W. W., & Payne, T. S. (2000). Detection of virulence to wheat stem rust resistance gene Sr31 in Puccinia graminis f. sp. tritici in Uganda. Plant Disease, 84, 203.Google Scholar
- Pretorius, Z. A., Szabo, L. J., Boshoff, W. H. P., Herselman, L., & Visser, B. (2012b). First report of a new TTKSF race of wheat stem rust (Puccinia graminis f. sp. tritici) in South Africa and Zimbabwe. Plant Disease, 96, 590.Google Scholar
- Sambrook, J., Fritsch, E. F., & Maniates, T. (1989). Molecular cloning, a laboratory manual (2nd ed.). New York: Cold Spring Harbour Laboratory Press.Google Scholar
- Visser, B., Herselman, L., & Pretorius, Z. A. (2009). Genetic comparison of Ug99 with selected south African races of Puccinia graminis f. sp. tritici. Molecular Plant Pathology, 10, 213–222.Google Scholar
- Visser, B., Herselman, L., Park, R. F., Karaoglu, H., Bender, C. M., & Pretorius, Z. A. (2011). Characterization of two new Puccinia graminis f. sp. tritici races within the Ug99 lineage in South Africa. Euphytica, 179, 119–127.Google Scholar