香蕉穿孔线虫28S rRNA基因的D2／D3区序列分析

Phylogentic Analysis of Radopholus similis from D2 and D3 Fragments of the 28S rRNA Gene Sequences

采用线虫通用引物D2A和D3B对9个香蕉穿孔线虫种群的核糖体DNA28S大亚基的D2/D3区进行了扩增,获得的片段长度约为780bp,克隆测序后使用UPGMA法进行聚类分析和构建系统发育树。结果表明9个线虫种群D2/D3区核苷酸序列相似性为99.13%,其中8个群体的序列与越南报道的香蕉穿孔线虫近源种(Radopholus sp.7B VietNam)的D2/D3区核苷酸序列(DQ328712)相似性为97.46%,说明香蕉穿孔线虫D2/D3区具有较大的保守性。聚类分析结果表明,RSHN12r、RSSH、RSHL、RSHK、RSLZ、RSSZ、RSHN13、RSHN12p等8个种群聚为一类,亲缘关系很近,RSHN3群体与以上8个群体亲缘关系较远,说明RSHN12r、RSSH、RSHL、RSHK、RSLZ、RSSZ、RSHN13、RSHN12p这8个香蕉穿孔线虫种群可能来源于同一地理种群,而RSHN3种群可能来源于另一个地理种群。

The amplification of D2 and D3 fragments of the 28S rRNA gene from Radopholus sirnilis populations detected from imported seedling and horticultural plants using universal primers（D2A and D3B） yielded one fragment about 780 bp. The results of D2 and D3 fragment sequence analysis and the alignment between the nine populations and related species Radopholus and Pratylenchus using UPGMA method showed that eight populations（RSHN12rR, RSSH, RSHL, RSHK, RSLZ, RSSZ, RSHN13） were clustered in the same group and the similarity between them was 99. 13%, while they were compared with the sequence of Radopholus sp. 7B VietNam（DQ328712）, the similarity was 97.46%. The results of phylogentic analysis with UPGMA program showed that there were two main branches, the first branch contained eight populations of R. similis （RSHN12rR, RSSH, RSHL, RSHK, RSLZ, RSSZ, RSHN13,RSHN12p）, they may have the same origin. And the second branch comprised of only one population（RSHN3） which may have another origin.