Understanding the inheritance of host resistance to mycosphaerella graminicola

随着保护和免耕生产实践的实施，将作物残留物保留在土壤表面，小麦残留物传播的叶斑病的发病率有所增加。三孢壳针孢斑点病是由禾生球腔菌（Mycosphaerella graminicola）引起的一种加拿大小麦叶斑病。在有利于病原体的条件下，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对这种疾病易感。焚烧作物残留物或使用杀真菌剂可以减少病原体造成的损失。然而，开发遗传抗性品种是减少潜在损失的一种更环保和经济的方法。抗性由许多独立的分离物特异性基因控制。这项研究的目的是：1）确定盐生壳针孢属第三种抗斑点病基因的染色体位置并鉴定与该基因连锁的分子标记，2）确定四倍体栽培品种Coulter中抗斑点病基因的染色体位置并鉴定与该抗性基因连锁的分子标记，3）评价不同抗性基因组合及其互作对不同毒力模式菌株的影响4）对Stb 14和Stb 13进行精细定位，并对这些抗性基因进行图位克隆，5）进一步明确了M.在加拿大西部收集的禾生菌分离物。从长远来看，本研究的结果将促进我们对小麦- M的认识。这将有助于制定更多的全球战略，以生产抗性小麦品种。 在短期内，基因定位的知识和分子标记辅助选择的可用性将形成一个坚实的基础，育种家可以有效地和快速地将抗性纳入适应品种。 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留物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.