小麦白粉病是一种世界性小麦病害，发掘抗性基因和培育抗病品种是减少白粉病损失最经济有效的途径。本课题组前期研究发现，两芒山羊草2Mb染色体携带白粉病抗性新基因。本项目拟以小麦-两芒山羊草2Mb二体附加系TA7733为材料，利用中国春ph1b基因诱导部分同源染色体之间高频重组，创制小麦-两芒山羊草2Mb易位系，并对易位系进行原位杂交鉴定、分子标记分析和抗性鉴定，筛选高抗白粉病的2Mb小片段易位系，定位抗性新基因于2Mb染色体特定区段，并获得与该基因紧密连锁的分子标记。对接种白粉菌前后的2Mb附加系和受体亲本中国春进行转录组测序和差异表达基因分析，并结合抗病基因区段定位结果，发掘位于2Mb染色体上的抗病相关基因。该项目的实施不仅为小麦白粉病抗性育种提供抗病新基因和共分离的分子标记，还为克隆该抗病基因以及进一步解析抗病分子机理奠定基础。

Powdery mildew is one of the most widespread diseases of wheat worldwide. Breeding resistant cultivars by utilization of powdery mildew resistance genes is considered to be the most economical and effective method of controlling this disease. It was found that Aegilops biuncialis chromosome 2Mb carried novel powdery mildew resistance gene(s) in our previous research. In this study, wheat-Ae. biuncialis 2Mb disomic addition line TA7733 will be used as bridge material to produce wheat-Ae. biuncialis 2Mb translocation lines by crossing the Chinese Spring (CS) ph1b mutant, which significantly elevates the frequency of homoeologous chromosome pairing and homoeologous recombination. The translocation lines will then be characterized by in situ hybridization (ISH) and molecular marker analysis, and evaluated for powdery mildew resistance at seedling stage in the greenhouse and at adult stage in the fields to select translocation lines with small 2Mb segments carrying high resistance gene(s) to powdery mildew. The novel gene(s) conferring powdery mildew resistance will be further cytologically mapped to the corresponding region of chromosome 2Mb, and the closely linked molecular markers will be developed. Furthermore, transcriptome sequencing will be applied to obtain extensive information about the transcriptomes of the disease-resistant addition lines TA7733 and susceptible recipient parent CS after inoculating Bgt isolates. Subsequently, differential expression genes between different materials will be analyzed to discover genes related to powdery mildew resistance locating on 2Mb chromosome by combining chromosomal localization of resistance gene(s). This study will not only provide novel powdery mildew resistance gene(s) and co-segregated molecular markers for wheat disease breeding, but also lay solid foundations for identifying resistance-related genes and further dissecting molecular and genetic mechanisms of disease resistance.