【目的】明确引起我国西南地区玉米灰斑病的致病菌玉米尾孢（Cercospora zeina）在中国的分布区域以及扩散路径，预测病害未来可能的扩展区域，为有针对性开展灰斑病的早防早控工作、保护玉米安全生产提供重要信息。【方法】利用NTSYSpc、Popgene 32、ClustalX1.83、BioEdit、DnaSP 5.0、Network4.5.0.2和Arlequin 3.11等软件，对127个采自中国云南、四川、贵州、湖北、重庆、甘肃、陕西和重庆的C. zeina分离物进行了基于ISSR技术的群体遗传多样性分析，对其中108个进行了基于5个基因片段的多基因序列分析。【结果】群体遗传多样性分析表明，中国的C. zeina种群具有较高水平的遗传分化，127个分离物被划分为2个大群和8个亚群。各地理种群内的遗传分化是种群结构变异的主要因素，地理种群间的遗传相似性与病菌扩展时间及方向一致。多基因序列分析表明，中国C. zeina种群存在9种单倍型，单倍型的分布与病菌传播路线相关，病菌定殖最早的云南种群出现了群体扩张事件。群体遗传多样性与多基因序列分析证明，C. zeina云南种群具有最高的遗传多样性和单倍型多样性，其他地理种群均源自云南种群的扩散。在印度洋西南季风作用下，云南C. zeina种群逐渐扩展至四川、贵州、陕西、甘肃和重庆，同时经过种子携带方式从云南直接进入湖北，并在风力作用下从湖北传入陕西、河南及相邻的重庆。【结论】首次明确了玉米灰斑病致病菌玉米尾孢的遗传变异及其在中国的传播和扩散路径，夏季季风以及种子带菌是该种灰斑病快速传播的主要因素；预计未来玉米尾孢灰斑病将在季风作用下继续缓慢向北方玉米区扩散，形成新的重大病害威胁。

Northern corn leaf blight (NCLB), caused by the heterothallic ascomycete fungus Setosphaeria turcica, is a destructive foliar disease of maize and represents a serious threat to maize production worldwide. A comparative proteomic study was conducted to explore the molecular mechanisms underlying the defense responses of the maize resistant line A619 Ht2 to S. turcica race 13. Leaf proteins were extracted from mock and S. turcica-infected leaves after inoculated for 72 h and analyzed for differentially expressed proteins using two-dimensional electrophoresis and mass spectrometry identification. 137 proteins showed reproducible differences in abundance by more than 2-fold at least, including 50 up-regulated proteins and 87 down-regulated proteins. 48 protein spots were successfully identified by MS analysis, which included 10 unique, 6 up-regulated, 20 down-regulated and 12 disappeared protein spots. These identified proteins were classified into 9 functional groups and involved in multiple functions, particularly in energy metabolism (46%), protein destination and storage (12%), and disease defense (18%). Some defense-related proteins were upregulated such as β-glucosidase, SOD, polyamines oxidase, HSC 70 and PPIases; while the expressions of photosynthesis- and metabolism-related proteins were down-regulated, by inoculation with S. turcica. The results indicated that a complex regulatory network was functioned in interaction between the resistant line A619 Ht2 and S. turcica. The resistance processes of A619 Ht2 mainly resided on directly releasing defense proteins, modulation of primary metabolism, affecting photosyntesis and carbohydrate metabolism.