基于COI基因解析我国茶网蝽种群遗传多样性和遗传结构

Analysis of Genetic Diversity and Genetic Structure in Geographic Populations of Stephanitis chinensis from China Based on Mitochondrial DNA COI Sequence

茶网蝽(Stephanitis chinensis)是我国西南茶区的重要害虫,近年有入侵成灾事件发生。为解析茶网蝽的生态适应机制和成灾规律,测定了茶网蝽12个种群共240头成虫COI基因序列,利用Dna SP 6.12.03、Arlequin3.5.2.2、MEGA 7.0.26等软件进行了遗传分化程度、基因流(N_(m))以及分子变异情况的分析。结果显示,茶网蝽12个地理种群的240条COI基因序列共包含75个变异位点和38个单倍型,其中仅Hap13是共享单倍型。茶网蝽总群体的单倍型多样性指数(H_d)为0.82779,地理种群的H_d在0.00~0.85,总群体的遗传分化固定系数(F_(ST))为0.86426,N_(m)为0.03987,表明我国茶网蝽群体遗传分化程度较高,基因交流较小。重庆城口、重庆巫溪、湖北恩施、湖北十堰、陕西汉中等5个种群相互之间遗传分化程度较低,基因交流频繁(F_(ST)<0.06,N_(m)>4.50),其他种群对之间分化程度较高,基因交流较少(F_(ST)>0.25,N_(m)<1.00)。分子变异分析(AMOVA)支持遗传分化主要来自于不同地理种群之间(86.43%)。Tajima’s D和Fu’s F_(s)中性检验支持重庆巴南、湖北恩施种群以及大巴山脉周边群体发生过种群扩张事件。本研究分析推测我国茶网蝽兼具入侵种群扩张成灾和原始种群扩张成灾的风险,建议有茶网蝽发生的茶区和大巴山脉周边茶园加强对该害虫的监测工作。

The tea lace bug,Stephanitis chinensis,is an important pest of the southwest tea region in China,which has spread and caused disasters in recent years.To analyze the ecological adaptation mechanism and disaster law of S.chinensis,COI sequences of 240 adults from 12 populations of this pest were sequenced.The genetic differentiation,gene flow level and molecular variance were analyzed by DnaSP 6.12.03,Arlequin 3.5.2.2 and MEGA 7.0.26,respectively.There were 75 mutation sites and 38 haplotypes in the COI sequences of 12 geographic populations,and only Hap13 was a shared haplotype.Haplotype diversity index(Hd)of the total population was 0.82779,Hd values between geographical populations ranged from 0.00 to 0.85.Fixed coefficient(FST)and gene flow(N_(m))value of total population were 0.86426 and 0.03987,respectively.The results indicate that there are a high degree of genetic differentiation and a small degree of gene exchange of the total population in China.Population pairs of 5 populations(CQCK,CQWX,HBES,HBSY and SXHZ)had low genetic differentiation and frequent gene exchange(FST<0.06,N_(m)>4.50),while other population pairs had high genetic differentiation and less gene exchange(FST>0.25,N_(m)<1.00).Molecular variance analysis(AMOVA)supports that the genetic differentiation was mainly among populations(86.43%).Tajima's D and Fu's F_(s) neutrality test support that population expansion events occurred in the CQBN,HBES populations and the whole population around the Daba Mountains.In this study,the risk of both invasion expansion and original population expansion of S.chinensis in China was analyzed and speculated.It suggests that the field monitoring of the tea lace bug should be strengthened in tea plantations.