DNA条形码在紫斑谷螟幼虫鉴定中的应用

Application of DNA barcoding in Pyralis farinalis larvae

紫斑谷螟Pyralis farinalis是常见的仓库害虫之一,它的识别和鉴定主要依靠传统的形态学鉴定方法,但对于残缺的虫体或幼虫,形态学鉴定方法则无法识别。本研究运用DNA条形码技术对送检的残缺幼虫进行鉴定。以提取到的样品基因组为模板,利用通用引物扩增其线粒体COI基因,所得基因序列与Gen Bank数据库中下载的螟蛾属5个种的14条序列进行序列比对,发现未知样品序列与紫斑谷螟的序列相似性最高,达到99.8%,遗传距离最小,为0.002-0.003。以玉米螟作为外群,采用K2P模型,以邻接法构建系统进化树,结果样品与紫斑谷螟聚为一枝。上述结果表明,残缺幼虫为紫斑谷螟的幼虫,这一结果为有效进行害虫防治提供依据。

Pyralis farinalis is one of the most common warehouse pests. The identification of P.farinalis mainly relies on traditional morphological method, which however, is infeasible for incomplete insect bodies or larvae. In this paper, an incomplete larva was identified through DNA barcode technology. Mitochondrial DNA was extracted and cytochrome oxidase subunit I （COI） gene fragments of the sample was amplified using the universal primers. Alignment analysis with fourteen homologous sequences of five different Pyralis species in GenBank revealed that the unknown sample had the highest sequences similarity of 99. 8% with the sequences of P.farinalis. The sample also showed the minimum genetic distance to P. farinalis, which was 0. 002 -0. 003. The phylogenetic tree was constructed by K2P model and the Neighbor- Joining method, and Ostrinia nubilalis was set as outgroup. The sample was revealed to be clustered with P.farinalis. The result suggested that the incomplete larva was Pyralis farinalis, which provides a powerful evidence for effective pest control.