中国玉米南方锈病病原菌遗传多样性

【目的】针对近年频繁暴发的玉米南方锈病，通过分子生物学技术，明确不同地区玉米南方锈病菌的遗传相似性，为研究该病害流行与发生规律和抗病育种提供信息。【方法】利用18对多态性ISSR引物对2011和2012年采集自12个省（自治区、直辖市）的72个菌株进行扩增，分析种群的遗传结构与特征。【结果】在相似系数0.81水平上，72个菌株被划为2群5亚群10组，亚群间表现出年度与地域的一定差异；遗传多样性分析表明菌株群体间存在较高的遗传变异；遗传相似性和遗传距离分析揭示山东与安徽、福建与浙江群体分别具有相对较高的相似性，而海南群体与其它群体遗传距离最远；不同地区病菌群体间缺乏基因交流，遗传相关性较低。【结论】引起中国不同地区玉米南方锈病的多堆柄锈菌群体具有较高的遗传变异；病菌遗传多样性分析结果初步证明，各地病菌无法在当地完成周年侵染循环；海南三亚冬季发生的玉米南方锈病不是中国其它地区病害的初侵染源，广东和广西等华南地区的玉米锈病也不是黄淮夏玉米区病害的初侵染源，中国大陆地区和海南岛的玉米南方锈病的初侵染源可能来自于中国大陆以外的其它地区。

Genetic Diversity of Puccinia polysora Underw. in China

【Objective】The objective of this study is to understand the genetic diversity of Puccinia polysora, the causal agent of Southern corn rust which is outbreaked recently in China, molecular techniques were used to analyze the genetic differences among the pathogen populations. 【Method】Seventy-two populations of P. polysora, collected from twelve provinces during 2011 and 2012, were amplified using eighteen polymorphic ISSR primers and the results were analyzed with software. 【Result】Seventy-two populations were clustered into ten branches at 81% Dice’s similarity coefficient, including two groups and five subgroups. There were some relationships in subgroup populations on collected loci and years and the higher genetic variations were tested among different populations. The higher genetic similarities were detected between Shandong and Anhui, Fujian and Zhejiang populations respectively, and the lowest similarities were between Hainan and others. The genetic relationship between provincial populations was lower based on the gene flow information.【Conclusion】There were higher genetic variations in populations of P. polysora, causal agent of southern corn rust, in China. Based on the molecular data, the pathogen did not complete the disease cycle in the field, and the population of P. polysora in Hainan was not the primary infection source in other provinces as well as the populations of P. polysora in Guangdong and Guangxi were not for summer-growing maize area. It was concluded that the primary infection source of P. polysora in mainland and Hainan island of China might come from other areas.