Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/27/2007
Publication Date: 7/28/2007
Citation: Ali, S., Friesen, T.L., Meinhardt, S., Rasmussen, J. 2007. A wheat genotype sensitive to Ptr ToxA and resistant to <i>Pyrenophora tritici-repentis</i> (Tan spot) races 1 and 2. Meeting Abstract.
Technical Abstract: Ptr ToxA is a host selective toxin produced by races 1, 2, 7, and 8 of Pyrenophora tritici-repentis , causal agent of tan spot of wheat. Toxin sensitivity in the host is conditioned by a single dominant gene designated TSN1. Most wheat genotypes that are toxin sensitive are also tan spot susceptible. Depending on genetic background of these toxin sensitive host lines, Ptr ToxA may act as a pathogenicity factor required for disease or a virulence factor that affects the rate of disease development and the lesion type ultimately formed. Host genotypes known to be toxin sensitive and disease resistant have been identified, but this phenotypic combination is somewhat rare, the resistance exhibited may be incomplete, and the genetic basis of the resistance is not well characterized. We report here a wheat genotype that is sensitive to Ptr ToxA but highly resistant to disease. Genetic analyses are underway to determine whether toxin sensitivity is conditioned by TSN1 and how many genes condition disease resistance in this wheat line. The discovery of this wheat genotype may broaden our understanding of the role of Ptr ToxA in disease development and may identify a novel source of genetic resistance to tan spot.