基于线粒体COI基因的中国西南地区木领针蓟马地理种群的遗传分化分析

【目的】木领针蓟马Helionothrips mube近年来成为芋头Colocasia esculenta上的一种常见害虫。本研究旨在探讨其中国西南地区地理种群间的遗传变异。【方法】通过Sanger法测定了21个地理种群132头木领针蓟马的线粒体COI基因序列，利用MEGA, DnaSP, Arlequin和Network等软件对木领针蓟马种群间的遗传多样性、遗传分化、分子变异等进行分析。【结果】获得的木领针蓟马132条线粒体COI序列(643 bp)中共发现34个变异位点、16种单倍型，其中单倍型H1出现频率最高、分布最广。木领针蓟马总群体的遗传多样性较高(Hd=0.712, Pi=0.00413, K=2.655)，遗传分化程度极大(Fst=0.3443)，基因交流水平不高(Nm=0.96)。分子方差分析(AMOVA)表明，木领针蓟马的遗传分化主要来自种群内部，Mantel检测出种群地理距离与遗传距离呈正相关。总群体中性检验Tajima’s D值显著负值，Fu’s Fs值不显著，错配分布曲线呈多峰。综合种群间遗传距离、单倍型系统发育树及中介网络图结果，表明四川成都(CHD)、云南昌宁(CHN)和贵州遵义(ZY)3个种群的遗传分化程度均高于其他种群。【结论】中国西南地区木领针蓟马总群体的遗传多样性较高，遗传分化明显，种群间的基因交流受到地理距离的影响，总群体在较近的历史时期内没有出现扩张现象。

Analysis of genetic differentiation among geographic populations of Helionothrips mube (Thysanoptera: Thripidae) in southwestern China based on mitochondrial COI gene

【Aim】 Helionothrips mube has become a common pest on the taro (Colocasia esculenta) in recent years. This study aims to investigate the genetic differentiation among different geographic populations of H. mube in southwestern China. 【Methods】 The mitochondrial COI gene sequences of 132 individuals of H. mube from 21 geographic populations were obtained through Sanger sequencing, and the genetic diversity, genetic differentiation and molecular variance were analyzed by MEGA, DnaSP, Arlequin and Network software. 【Results】 Thirty-four variable sites were observed and 16 haplotypes were defined based on the 132 mitochondrial COI sequences (643 bp) from 21 geographic populations of H. mube, of which H1 had the highest frequency and the widest distribution. High levels of genetic diversity (Hd=0.712, Pi=0.00413, K=2.655) and genetic differentiation (Fst=0.3443), and low gene flow (Nm=0.96) were detected in the total population of H. mube. The analysis of molecular variance (AMOVA) indicated that the genetic differentiation of H. mube was mainly attributed to the intra-population. The Mantel test showed a positive correlation between the geographic distance and genetic distance. The neutral test showed that Tajima’s D value was significantly negative, but Fu’s Fs was not significant, and the mismatch distribution curve showed multiple peaks based on the whole datasets. The results of genetic distance among populations, haplotype phylogenetic tree and median-joining network all supported that the population genetic differentiation among the three populations of Chengdu, Sichuan (CHD), Changning, Yunnan (CHN) and Zunyi, Guizhou (ZY) were greater than that among other populations. 【Conclusion】 The H. mube populations in southwestern China are characterized by high genetic diversity and obvious genetic differentiation, the gene flow among populations might be affected by geographical distance, and the population of H. mube has not experienced recent expansion.