抗白粉病新基因Pm45的精细定位与评价研究

Powdery mildew is a major impact to the production safety of wheat. Since the genes that resistant to powdery mildew lose their function gradually after used in production, that dicover and use new resistant genes is of great importance. Through the resistance analysis of collection of wheat germplasm, common wheat variety D57 showed resistance to Nanjing area mixed powdery mildew. Genetic analysis shows that D57 contains two dominant powdery mildew resistant genes, one of which was located on the chromosomes 6DS, a new powdery mildew resistance gene. This gene has been located between molecular markers Xcfd80-Xmag6140, then named Pm45. The project plans to fine map and evaluate the resistance of Pm45. According to the collinearity in the grass family (such as rice, Brachypodium sylvaticum and wheat), the new markers that closely link to the target gene will be developed through bioinformatics methods, which will narrow the distance between marker and target gene. additionally, through the marker-assisted selection, Pm45 will be inducted into the main varieties in different ecological zones. Resistance identification in these wheat product areas will help us evaluate Pm45 in breeding. Fine mapping of Pm45 will be conducted through screening and analysis of recombinants derived from secondery population. This project can lay a foundation for further clarify the mechanism of powdery mildew gene in wheat, and broaden genetic basis of wheat resistance to powdery mildew.

白粉病是影响小麦生产的主要病害，近年来在我国危害日益严重。抗病基因的发掘是抗病育种的基础。通过种质筛选和遗传分析，本课题组在普通小麦D57中发现了一个显性抗白粉病新基因，并将其定位于染色体6DS上。该基因对南京地区的混合白粉病菌及分离的所有19个生理小种表现免疫。尽管前期研究中获得了与目标基因紧密连锁的标记，但采用的定位群体较小，重组相对较少，定位结果相对粗放。为了克隆该基因并进一步研究抗白粉病机制，本项目拟在现有工作基础上，借助分子标记辅助选择，通过回交构建近等基因系及次级F2分离大群体，将该基因精细定位到0.5cM范围内。同时进一步评价该基因在不同生态环境下的抗性。本研究为进一步明确该抗白粉病基因的作用机制奠定基础,对于拓宽普通小麦抗白粉病的遗传基础具有重要意义。