Understanding the inheritance of host resistance to mycosphaerella graminicola

点击翻译按钮获取中文摘要

The incidence of residue-borne leaf spotting diseases of wheat has increased with implementation of conservation and no-till production practices that retain crop residues on the soil surface. Septoria tritici blotch, caused by the fungal pathogen Mycosphaerella graminicola, is a leaf spotting disease of wheat in Canada. Yield losses as high as 50% can occur under conditions that favor the pathogen. Most commercial cultivars of wheat grown in western Canada are susceptible to this disease. Burning of crop residues or use of fungicides can reduce losses caused by the pathogens. However, development of genetically resistant cultivars is a more environmentally and economically sound method of reducing potential losses. Resistance is controlled by a number of independent isolate-specific genes. The objectives of this research are to: 1) determine the chromosome location of the third Septoria tritici blotch resistance gene in Salamouni and identify molecular markers linked this gene, 2) determine the chromosome location of the Septoria tritici blotch resistance genes in the tetraploid cultivar Coulter and identify molecular markers linked to the resistance genes, 3) evaluate the effect of different combinations of resistance genes and their interaction to isolates with different virulence patterns 4) fine map Stb14 and Stb13 and proceed to map-based cloning of these resistance genes and 5) further characterize the differentiation in virulence of M. graminicola isolates collected in western Canada. In the long term the results of this research will advance our knowledge of the wheat- M. graminicola interaction and will assist in the development of more global strategies for production of resistant wheat cultivars. In the short term, knowledge of gene location and availability of molecular markers for marker assisted selection will form a solid foundation from which breeders can effectively and rapidly incorporate resistance into adapted cultivars. Resistant cultivars will reduce losses to producers. Reduced use of fungicides or burning of crop residues will benefit the environment and the general public.