Genetic characterization of the triticum-stagonospora nodorum pathosystem

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Plant diseases cause significant economic losses to field and horticultural crops in Canada, affecting the entire Canadian economy from producers to consumers. Direct financial losses result from decreased quantity and quality of plant produce, but indirect costs can result from pathogen-produced toxins that affect human and animal health. Fungal pathogens cause the majority of plant diseases and have evolved different strategies for successfully infecting their plant hosts. One strategy is necrotrophy, where the fungus kills host tissue before or during fungal invasion. Nutrients are extracted from the dead host tissue for fungal growth and reproduction. The production of toxins is a key determinant of pathogenesis for necrotrophic fungi. The long-term goal of this research program is to uncover the molecular basis of interactions between necrotrophic fungal pathogens and their plant hosts. The Triticum-Stagonospora nodorum pathosystem will be used in this research as a model pathosystem. S. nodorum (synonym Septoria nodorum, teleomorph Phaeosphaeria nodorum) is a common necrotrophic pathogen of Triticum aestivum (common wheat) and Triticum turgidum subspecies durum (durum wheat) in Canada, and causes the leaf spotting disease stagonospora nodorum blotch (SNB). The main objectives of this program are: 1) the identification of the fungal genes involved in the pathogenesis of Triticum species by S. nodorum and 2) identification of Triticum genes conferring SNB resistance. A combination of linkage and association mapping strategies will be used to study the genetics of host-pathogen interactions. Linkage mapping is a robust genetic analysis method that has been widely applied in plant and fungal genetic research. Association mapping is a novel gene mapping approach used extensively in human and animal genetic research. These studies will provide insight into the genetic basis of virulence and pathogenicity of a necrotrophic pathogen, and identify and characterize resistance genes in the host. This information will advance scientific knowledge in this discipline and has applications in breeding of disease resistant crops.