Pathogenic, genetic and molecular characterization and differentiation of races in Colletotrichum truncatum from lentil

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Anthracnose caused by the fungal pathogen Colletotrichum truncatum is a major disease of lentil in the Canadian Prairies, control of which is costing lentil producers a significant amount of money through fungicide applications, yield loss and downgrading of seed due to poor quality. Use of cultivars resistant to the two identified races is considered to be the most economical and environmentally safe way of controlling the disease. Long-term success in resistance breeding has been hampered by a lack of knowledge of the pathogenic diversity of the fungus in the field, the potential of the pathogen to adapt to resistant cultivars, and factors that govern virulence in the fungus to specific resistance genes(s) in lentil. Using isolates with known race identity, we will identify molecular markers for virulence and use those to determine the distribution of races in lentil fields. Isolates collected for that purpose will also be used for a molecular population study to determine whether the fungus is outbreeding in nature and thus could develop new races through sexual recombination. With the help of a progeny population from a cross of the two races, we will conduct a genetic study to determine inheritance of virulence in this fungus. A genetic linkage map for Colletrotrichum truncatum will be developed. We also intend to investigate the infection biology of the two races on susceptible and resistant lentil genotypes by microscopy and with molecular tools to identify critical points in the interaction, and to determine virulence mechanisms in the pathogen. In doing so we will develop a cDNA library from infected lentil leaves that will allow us to identify genes involved in virulence in the pathogen, and in future those involved in resistance. Potential function of targeted genes will be confirmed by gene-disrupted mutants. The results of this project will allow the industry partner, together with plant breeders and pathologists, to develop a long-term strategy for the development of durable resistance to anthracnose, and to monitor the pathogen in an efficient way in future using technology and research tools developed in this project.