Understanding the inheritance of host resistance to mycosphaerella graminicola

小麦残茬病的发病率随着保留作物残茬在土壤表面的保护性和免耕生产实践的实施而增加。黑穗病是加拿大小麦的一种斑叶病，由真菌病原菌引起。在有利于病原菌的条件下，产量损失可高达50%。在加拿大西部种植的大多数商业小麦品种都易患此病。焚烧作物残茬或使用杀菌剂可以减少病原体造成的损失。然而，开发具有遗传抗性的品种是一种更环保和经济的减少潜在损失的方法。抗性是由一些独立的分离特异性基因控制的。本研究的目的是：1)确定了第3个稻瘟病抗性基因在Salamouni中的染色体定位，并鉴定了该基因的连锁分子标记；2)确定了稻瘟病抗性基因在四倍体品种Coulter中的染色体定位，并鉴定了抗性基因的连锁分子标记；3)评价不同抗性基因组合及其相互作用对不同毒力型菌株的影响；4)对Stb14和Stb13抗性基因进行精细定位，并进行抗性基因的图谱克隆；5)进一步表征加拿大西部采集的稻瘟病菌分离株的毒力差异。从长远来看，这项研究的结果将促进我们对小麦- graminicola相互作用的认识，并将有助于制定更多生产抗性小麦品种的全球战略。在短期内，基因定位的知识和标记辅助选择的分子标记的可用性将为育种者有效和快速地将抗性纳入适应品种奠定坚实的基础。抗性品种将减少生产者的损失。减少使用杀菌剂或焚烧作物残茬将有利于环境和公众。

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.