大小蠹来源地的COⅠ基因标记

Investigating the provenance of Dendroctonus using COⅠ gene

【背景】大小蠹属昆虫是重要的林木害虫,我国口岸有多次截获记录,确定大小蠹的来源地可以有针对性地加强对大小蠹的检验检疫工作。【方法】测定了5种高风险大小蠹(红脂大小蠹、红翅大小蠹、中欧山松大小蠹、落叶松大小蠹和间大小蠹)共12个样本的线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ)的部分序列。【结果】利用巢式PCR技术,在不同种类的大小蠹样本中均获得了530bp的靶标片段,比对分析显示,不同种大小蠹之间的COⅠ序列差异显著,同种大小蠹不同个体之间的COⅠ序列存在一定的差异,但差异不显著。系统进化树分析结果显示,大小蠹可以明显分为2支,其中,间大小蠹单独为一分支,另一分支由红脂大小蠹、红翅大小蠹、中欧山松大小蠹和落叶松大小蠹组成;同时,同种大小蠹不同个体的来源情况在进化树中有一定体现。【结论与意义】COⅠ基因可以较好地反映样本的来源地,对今后制定大小蠹的具体检验检疫措施有实际指导意义。

[ Background ] Dendroctonus spp., the noxious forest pests, have been repeatedly intercepted in many ports in China. For custom officers, the main challenge remains to determine the provenance of these insects. [ Method ] Using nested PCR, the cyto- chrome C oxidase subunit I gene （ COI ） in mtDNA was examined for 12 samples from Dendroctonus valens, D. rufipennis, D. pon- derosae, D. simplex and D. adjunctus. [ Result ] The nested PCR showed variation between and within groups for a 530 portion of COI. Molecular phylogenetic analysis based on COI gene showed that Dendroctonus spp. could be divided into two clades. Clade 1 included D. adjunctus, and Clade 2, D. valens, D. rufipennis, D. ponderosae and D. simplex. The provenance of the specimens an- alyzed in this study can be identified within the evolutionary tree. [ Conclusion and significance] The results suggest that COI may help determine the provenance of specimens intercepted in ports thus providing more adequate information to custom officers.