中国柱花草炭疽病原菌遗传多态性的RAPD分析

在对中国柱花草炭疽病进行广泛调查和病原采样收集的基础上，利用RAPD分子标记技术对43个代表性菌株进行了基因组DNA分析，并与276份国外菌株进行了综合聚类分析。结果表明所用8个引物的扩增片段位于0.3～2.8kb之间， 菌株间呈现显著的DNA多态性。以柱花草起源中心——南美的柱花草炭疽菌分类为基础，中国柱花草炭疽菌可划分成3大类型即Ⅱ、Ⅲ、Ⅵ类。中国菌株与来自柱花草起源中心——南美的菌株相比之下，其生物多样性和遗传变异性则相对简单。就中国菌株而言海南菌株与广西、广东菌株相比多样性较丰富， 中国柱花草胶孢炭疽菌正在出现种内遗传分化。 从聚类结果看，通常来自于同一个地理区域或同一个寄主基因型的菌株聚成一类， 即同一RAPD聚类组内的菌株通常来自于同一寄主基因型或同一地理区域。说明来自不同寄主基因型或物种的炭疽菌在遗传基因上具有专化性，而地理上隔离的国家或地区的柱花草炭疽病原菌各自具有相对独立的进化途径。

Genetic Diversity Analysis of Chinese Stylo Anthracnose Pathogens Using Random Amplified Polymorphic DNA

Genetic diversity of 43 Colletotrichum gloeosporioides isolates from stylo in China were analyzed using random amplified polymorphic DNA (RAPD) with eight arbitrary 10-base oligonucleotide primers compared with 276 isolates from other countries including two of Colletotrichum cutaturn based on a wide survey and disease sample collection. The results showed a good DNA polymorphism between isolates. The amplified fragments were between 0.3-2.8 kb. Chinese isolates were grouped in clusters II, III and VI with the majority in cluster VI based on six clusters of isolates from South America, the centre of origin of Stylosanthes genus. The genetic variation in the Chinese pathogen population was very limited compared with that in South America, the centre of host-pathogen diversity. The results also showed that a genetic variation in Chinese population of Colletotrichum gloeosporioides existed, though this variation was less significant. Isolates grouped by geographic origin and host species or genotypes indicated isolates from different host species or genotypes had their own parasitic specialization on genetic basis and pathogens from different countries evolved in their own way relatively.