Understanding the inheritance of host resistance to mycosphaerella graminicola

随着保护和免耕生产措施的实施，残留物传播的小麦叶斑病的发病率有所增加，这些措施将作物残留物保留在土壤表面。小麦斑点病是由真菌病原菌--禾谷分枝菌引起的一种小麦叶斑病。在有利于病原菌的条件下，产量损失可能高达50%。在加拿大西部种植的大多数商业小麦品种对这种疾病都很敏感。焚烧农作物残渣或使用杀菌剂可以减少病原体造成的损失。然而，开发抗遗传品种是一种更环保、更经济的减少潜在损失的方法。抗性由多个独立的分离物特异基因控制。本研究的目的是：1)确定Salnui中第三个抗黑斑病基因的染色体位置并定位与该基因连锁的分子标记；2)确定四倍体品种Coulter中抗病基因的染色体位置并确定与其连锁的分子标记；3)评估不同的抗性基因组合对不同毒力模式菌株的影响及其相互作用；4)对Stb14和Stb13进行精细定位，并对这些抗性基因进行图位克隆；5)进一步表征加拿大西部稻瘟病菌分离物的致病力分化。从长远来看，这项研究的结果将促进我们对小麦-禾谷病菌相互作用的了解，并将有助于制定更全球化的抗病小麦品种生产策略。从短期来看，基因定位知识和用于标记辅助选择的分子标记的可用性将为育种者有效、快速地将抗病整合到适应品种中奠定坚实的基础。抗病品种将减少生产者的损失。减少杀菌剂的使用或焚烧作物残渣将使环境和公众受益。

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.