稻瘟病菌群体的分子遗传学研究I.广东省1998~1999年稻瘟病菌的遗传多样性

MOLECULAR GENETIC STUDIES ON THE RICE BLAST FUNGUS POPULATION I. GENETIC DIVERSITY OF THE RICE BLAST FUNGUS POPULATION IN CHINESE GUANGDONG: 1998~1999

从80个随机引物中筛选到带型清晰、多态性及重复性均好的10个引物,对采自广东省1998-1999年四个自然生态稻作区的101个稻瘟病菌菌株进行随机扩增多态性DNA (Random Amplified Polymorphic DNA, RAPD) 指纹分析。10个引物共扩增出113条多态性带,表明广东省稻瘟病菌具有丰富的遗传多样性;RAPD分析可为该菌的遗传多样性分析提供大量的分子标记。对菌株间相似性系数和应用加权算术平均组对法 (Unweighted Pair Group Method using Arithmetic Average, UPGMA) 构建的聚类树状图进行分析,以相似性系数为0.62阀值时,可将101个菌株划分为14个遗传宗谱;其中宗谱1及宗谱2的菌株数占总数的80.2%,为优势宗谱; 其余的20个菌株分别归属于其他12个宗谱,由此说明广东省的稻瘟病病原菌群体既存在很突出的优势宗谱,又存在较多具遗传多样性的小宗谱。分析不同稻作生态区的菌株发现,每个稻作生态区既有共同的宗谱,又有其特异的宗谱;广东省稻瘟病菌群体遗传多样性的组成在不同生态稻作区是相对地比较稳定的。分析不同年份和早晚稻生长季节采集的菌株发现,广东省稻瘟病菌群体遗传多样性在年份和早晚稻生长季节之间也存在一定的特异性。

Genetic diversity of the rice blast fungus population in Guangdong Province, China was assessed with RAPD (random amplified polymorphic DNA) markers.Ten primers selected from 80 random primers and 101 isolates collected from four rice-growing regions in early and late seasons in 1998 and 1999 were used in the present study. A total of 113 polymorphic bands were amplified with the 10 primers, indicating that RAPD is a certain approach to unravel the genetic diversity of the rice blast population in Guangdong. The similarity coefficient and the graph of genetic lineages of isolates were analyzed with Unweighted Pair Group Method using Arithmetic Average (UPGMA), and 101 isolates were divided into 14 genetic lineages with the similarity coefficient of 0.62. Among the 14 genetic lineages, lineages 1 and 2 consisted of 39 and 42 isolates, respectively, whereas the other 12 lineages, each consisted of less than 3 isolates, indicating the rice blast population in Guangdong could be characterized by the two predominant lineages in combination with small diversified lineages. Furthermore, the isolates originated from different rice-growing regions as well as seasons were formed the common and the specific lineages, suggesting the rice blast population in Guangdong seems to carry the regional and temporal characteristics.