Biosecurity Research Articles
Ubiquity of ToxA and absence of ToxB in Australian populations of Pyrenophora tritici-repentis
Document Type
Article
Publication Date
1-2010
Journal Title
Australasian Plant Pathology
ISSN
Print: 0815-3191 Electronic: 1448-6032
Keywords
yellow leaf spot
Abstract
Pyrenophora tritici-repentis, the causal organism of the necrotrophic foliar wheat disease tan spot [also known as yellow (leaf) spot in Australia] is an important disease in Australia and in many parts of the world. North American isolates of the pathogen have been shown to produce combinations of three host-specific toxins, ToxA, ToxB and ToxC. Each toxin interacts with a host sensitivity locus, respectively Tsn1, Tsc2 and Tsc1. The virulence of an isolate is partially correlated with the presence of these toxins and resistance in the host is associated with absence of the sensitivity loci. Breeding for resistance to tan spot can, therefore, be aided by knowledge of the prevalence of the toxin-encoding genes in local pathogen populations. Two of the toxins, A and B, are encoded by known genes and molecular tests for the genes have been developed. We screened a diverse collection of 119 tan spot isolates collected between 1984 and 2008 and from all affected regions of Australia (Queensland, New South Wales, Victoria and Western Australia). In all cases, the gene for ToxA was present and the gene for ToxB was absent. The implications for resistance breeding and epidemiology of the disease are discussed. We also define a diagnostic molecular marker for P. tritici-repentis.
Recommended Citation
Antoni, E.A., Rybak, K., Tucker, M.P. et al. Ubiquity of ToxA and absence of ToxB in Australian populations of Pyrenophora tritici-repentis. Australasian Plant Pathology 39, 63–68 (2010). https://doi.org/10.1071/AP09056
