基于线粒体COⅠ基因序列的中国二点委夜蛾遗传多态性分析

Analysis of genetic polymorphism of Athetis lepigone(Lepidoptera:Noctuidae) populations from China based on mtDNA COⅠ gene sequences

二点委夜蛾Athetis lepigone是2005年首次在河北省发现危害夏玉米苗的新害虫,2011年7月在河北、河南、山东、山西、安徽和江苏6省47市夏玉米苗期大面积暴发成灾,严重威胁玉米生产。为了从种群水平探讨该虫暴发成灾的机制,我们通过分析线粒体细胞色素氧化酶亚基Ⅰ(mtCOⅠ)基因序列来研究不同地区二点委夜蛾种群的进化关系。本研究采集了河北、河南、山东和山西等地的19个不同地理种群样本,用同源序列比对的方法分析样本mtCOⅠ基因片段,利用DnaSP5.0软件和Arlequin3.5软件对不同地理种群间的mtCOⅠ单倍型多样性分析和Tajima’sD中性检测,建立了单倍型邻接(N-J)系统发育进化树和单倍型网络图。结果表明,在203头个体的658bpmtCOⅠ基因片段中,得到17种单倍型和18个变异位点,河北省的二点委夜蛾的单倍型多态性最丰富,而河南、山东和山西3省采集的二点委夜蛾样品其单倍型均有与河北种群单倍型一致的类型。二点委夜蛾不同地理种群间基因流水平较高,种群间没有明显的遗传分化,并且在较近的历史时期未经历明显的种群扩张。

Athetis lepigone is a newly recorded insect pest of summer corn seedlings,which was first found in Hebei province in 2005 and broke out on a large scale in Hebei,Henan,Shandong,Shanxi,Anhui and Jiangsu in July,2011.In order to explore its outbreak mechanisms at the population level,we analyzed the genetic diversity of A.lepigone populations from four provinces of China using mitochondrial cytochrome oxidase subunit Ⅰ（mtCOⅠ） gene.The partial sequences（658 bp） of mtCOⅠ gene in 19 geographic populations of A.lepigone were sequenced and analyzed through homologous sequence alignment.We also carried out the mtCOⅠ haplotype diversity analysis and Tajima＇s D test,and constructed the Neighbor-Joining（N-J） phylogenetic tree and haplotype network of COⅠ haplotypes of different populations using DnaSP 5.0 and Arlequin 3.5,respectively.The results showed that there were 17 haplotypes and 18 variable sites in the total 203 individuals.The analysis of phylogenetic tree and haplotype network based on 17 mtCOⅠ haplotypes indicated that the polymorphism of mtCOⅠ haplotypes of A.lepigone populations from Hebei province was the highest among four provinces.The haplotypes of A.lepigone populations from Henan,Shanxi and Shandong were the same as those from Hebei population.However,the results of Tajima＇s D test suggested that total populations did not experience obvious expansion in recent history.These results suggest that the level of gene flow among all populations of A.lepigone is high,and there is not obvious genetic differentiation among populations.