Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 2005
Publication Date: July 30, 2005
Citation: Friesen, T.L., Faris, J.D., Meinhardt, S.W. 2005. A new host selective toxin produced by stagonospora nodorum and its significance in disease using a segregating wheat mapping population. American Phytopathological Society Abstracts. Vol. 95:S32. Technical Abstract: Stagonospora nodorum blotch is a devastating disease of wheat and durum throughout the world. We have recently identified a new host selective toxin (SnTox2) from culture filtrates of Stagonospora nodorum. The toxin shows selective action on several different wheat genotypes indicating that it is a host-selective toxin (HST). The Brazilian hard red spring wheat breeding line BR34 and the North Dakota wheat cultivar ‘Grandin’ were found to be insensitive and sensitive respectively, to SnTox2. A mapping population consisting of 118 recombinant inbred lines of the cross of BR34 and Grandin was evaluated for toxin reaction and used to map the gene conditioning sensitivity to SnTox2. This gene, designated as Snn2, was mapped to the end of the short arm of chromosome 2D. This is the first report identifying this putative HST from S. nodorum and the chromosomal location of a host gene conferring its sensitivity. A fungal inoculation was used to evaluate the significance of Snn2in disease. Inoculation data revealed that when using a an SnTox2 producing isolate, Snn2 accounts for as much as 60% of the disease reaction with other minor QTL accounting for smaller portions of the disease variability.