基于CO1、CytB及28S基因的西藏圆柏大痣小蜂分子系统发育研究

The Study on the Molecular Phylogeny of Megastigmus sabinae from Tibet Based on CO1, CytB and 28S Genes

圆柏大痣小蜂Megastigmus sabinae是西藏自治区昌都市大果圆柏的主要种实害虫,对该树种的自然更新和育种等工作造成了严重的危害,为此本研究对圆柏大痣小蜂CO1、CytB及28S基因的部分序列进行了测序分析,以期为该害虫的防治和鉴定提供理论基础。结果表明:圆柏大痣小蜂CO1和CytB基因具有昆虫线粒体基因的核苷酸组成特征,而28S基因偏向使用碱基G和C,与线粒体基因形成了对比。CO1、CytB和28S基因碱基的使用频率存在偏向性。圆柏大痣小蜂与M. bipunctatus、M. amicorum等有较近的遗传进化距离。三种基因的转换率明显大于颠换率,而不同基因间,其转换和颠换的具体模式存在差异性。大痣小蜂线粒体CO1和CytB基因密码子使用具有节肢动物样的偏向性。进化分析表明,圆柏大痣小蜂与M. bipunctatus有很近的进化关系。该研究结果为大痣小蜂的综合防治提供了理论依据。

Megastigmus sabinae is a major Seed Pest of Sabina vulgaris at Changdu area in Tibet Autonomous Region, which has caused serious damage to the natural regeneration and breeding of this species. In this study, the partial sequences of CO1, Cytb and 28S genes of this specie were sequenced and analyzed in order to provide a theoretical basis for the control and identification of this pest. The results showed that: The genes CO1 and CytB of M. sabinae had composition features of mitochon-drial genes of arthropods, while the gene 28S had usage bias to nucleotide G and C comparing to the mitochondrial genes. M. sabinae had closer distance with M. bipunctatus, M. amicorum, etc. The conversion ratios of three genes were obviously larger than that of transition, and among the indi-vidual gene, the patterns of conversion and transition displayed divergence. The codon usage of mitochondrial genes CO1 and CytB of M. sabinae showed bias as that of arthropods. The phylogenetic analysis showed that M. sabinae had the very closer relationship with M. bipunctatus. The results in this study will provide the theoretical evidence for comprehensive control of M. sabinae.