米尔顿姬小蜂线粒体16S rRNA与COⅠ基因片段序列测定及分析

Amplification and sequence analysis of mitochondrial 16S ribomal RNA and cytochrome oxidase Ⅰ genes from the invasive Anselmella miltoni (Hymenoptera)

【背景】米尔顿姬小蜂是一种入侵我国台湾地区的植食性小蜂,能够严重影响水果的产量和食用价值。目前在我国大陆没有分布,由于其个体微小,与近似种区别较小,通过传统的形态学分类方法难以鉴定,因此有必要研究其基因片段序列,探讨分子鉴定方法。【方法】利用PCR方法扩增并测定了米尔顿姬小蜂线粒体16SrRNA和COⅠ基因的部分序列,并对各序列的碱基组成进行了分析。然后根据COⅠ基因部分序列,利用DNAMAN的Maximum Likelihood方法构建了米尔顿姬小蜂与膜翅目其他科的系统发育树。【结果】16SrRNA基因的PCR扩增产物为426bp,COⅠ基因的PCR扩增产物为488bp。通过测序获得米尔顿姬小蜂16SrRNA和COⅠ基因部分序列,序列分析表明,16SrRNA和COⅠ基因的A+T含量均较高,存在较强的A+T偏向性。系统发育树显示,米尔顿姬小蜂与蚜小蜂科的Encarsia berlesei亲缘关系最近,与姬小蜂科的Chrysocharis nautius、C.eurynota亲缘关系较远。【结论与意义】本研究为米尔顿姬小蜂的分子鉴定提供了依据。

[ Background ] Anselmella miltoni Giranh is a newly invasive phytophagous wasp in Taiwan, China, so far not detected on the Chinese mainland. The species is difficult to identify because this wasp is tiny and similar to other species of Hymenoptera. Studies on gene sequence with PCR may provide a useful identification tool. [ Method] Partial sequences of the mitochondrial 16S ri- bosomal RNA （rRNA） and cytochrome oxidase ] （COI） genes in A. miltoni were amplified and sequenced by using a polymerase chain reaction and DNA sequencing methods. A phylogenetic tree was built by using DNAMAN Maximum Likelihood method based on the COl partial sequences. [Result]Mitochondrial 16S rRNA and COI PCR products were 426 bp and 4~8 bp in length, re- spectively. The sequence analysis results showed that A ＋ T base composition in both 16S rRNA and COI gene sequences were high- er than C ＋ G. The phylogenetic tree indicated that the kinship between A. miltoni and Enearsia berlesei were the most closely, the relationship between A. miltoni and Chrysoeharis nautilus, C. eurynota were relatively distant. [ Conclusion and significance ] This study identified a possible avenue for the molecular identification of A. miltoni.