我国南方地区主要根结线虫DNA变异的RAPD分析

 本试验用5组随机引物对来自我国南方地区的30个根结线虫种群进行RAPD分析,并从中筛选出多态性较好的引物12个。共扩增出179条DNA多态带,各供试种群间存在着丰富的遗传多态性。扩增结果表现出种间差异大于种内差异的共同趋势,这表明上述12个引物能够较客观地反映种群间亲缘关系的远近。北方根结线虫与另外3种线虫(南方根结线虫、爪哇根结线虫、花生根结线虫)的亲缘关系最远;在3种主要根结线虫中,爪哇根结线虫与南方根结线虫的亲缘关系相对较近。基于种群间的相似系数分析和应用UPGMA法构建的聚类树状图,显示出不同的根结线虫在较低的相似性系数范围聚类,而绝大多数种内的不同种群均以较高的相似性系数聚在一起,这与形态分类基本一致,反映了形态学分类的分子遗传本质,同时也表明了应用RAPD技术进行根结线虫亲缘关系分析和种类鉴定具有合理性和可行性。本文还对RAPD方法对南方根结线虫小种鉴定的可能性进行了初步探讨。

DNA polymorphism of root-knot nematodes in South China revealed by RAPD

Among 48 random primers selected for detecting the genetic polymorphism of genomic DNA of 30 populations, 12 arbitrarily primers were suitable for RAPD analysis. With the 12 primers, 179 polymorphic bands were obtained. There were no RAPD bands sharing by all the 30 populations, which revealed the abundant diversity among the tested species. The di- versity level among the species was greater than that within the species. All these results indicated that the 12 primers are suitable for detecting the genetic diversity and relationship among these populations. Meloidogyne hapla appeared in a most distant group from the other three (M. arenaria, M. javanica and M. incognita ). Among the three major Meloidogyne species, M. javanica and M. incognita was seen to be the more closely related. The cluster analysis based on the RAPD bands showed that different species clustered in low D value, but different populations in the same species in higher D value. The result was almost consistant with what revealed by the morphological studies and other DNA analysis. It indicated that RAPD analysis is rational and feasible for identificating and genetic diversity analysising of root-knot nematodes. The possi- bility for the identification M. incognita races by RAPD was discussed.