Wolbachia在花蓟马中的感染及其与寄主线粒体DNA多样性的关系

Wolbachia infection and its relationship with mt DNA diversity in the flower thrips,Frankliniella intonsa(Thysanoptera: Thripidae)

[目的]Wolbachia是一种广泛存在于节肢动物中的胞内共生细菌,影响寄主的生物学特性。花蓟马Frankliniella intonsa（Trybom）是重要的害虫,对农作物及园林植物造成危害。本研究旨在明确Wolbachia在花蓟马中的感染情况,并分析其与寄主线粒体DNA多样性的关系。[方法]采集中国境内26个花蓟马自然种群,运用多位点序列分型技术（multilocus sequence typing,MLST）对其体内Wolbachia感染率及株系进行分析;利用线粒体COI分子标记研究花蓟马的遗传分化及遗传多样性;通过比较感染和未感染Wolbachia个体COI数据,探究Wolbachia多样性与寄主线粒体DNA多样性之间的关系。[结果]花蓟马中Wolbachia的感染率为0%~60%,共检测到5种Wolbachia株系（w Fint1,w Fint2,w Fint3,w Fint4及w Fint5）,均属于B大组且形成一个单系群。Wolbachia感染情况与这些花蓟马种群（除CC,GZ,TA和TY,N〈5）的线粒体DNA多样性相关,表现为不感染Wolbachia的种群中线粒体DNA单倍型多样性（Hd）与核苷酸多样性（Pi）均高于感染Wolbachia的种群,且Wolbachia感染率与Hd呈显著负相关（P〈0.05）。AMOVA分析表明花蓟马线粒体DNA遗传分化与Wolbachia感染情况有关。[结论]Wolbachia可能在侵染花蓟马种群后出现遗传分化;Wolbachia感染与寄主线粒体DNA多样性有关。

[ Aim ] Wolbachia is a bacterial endosymbiont that is found in a wide variety of arthropods, and affects the biological characteristics of host. The flower thrips, Frankliniella intonsa （Trybom） , is an important pest, and can cause damages to crops and garden plants. This study aims to examine the infection status of Wolbachia and its relationship with the mtDNA diversity of the host flower thrips. [ Methods ] The Wolbachia infection in 26 natural populations of F. intonsa was analyzed by using muhilocus sequence typing （MLST） in China. The genetic diversity and genetic differentiation of F. intonsa were investigated by using COl genetic markers. The COI data between the Wolbachia-infected and uninfected individuals were compared to explore the relationship between Wolbachia diversity and host mtDNA diversity. [ Results ] The prevalence of Wolbachia in the F. intonsa populations ranged from 0% to 60%. Five Wolbachia strains （wFintl, wFint2, wFint3, wFint4 and wFint5） were detected. All the detected strains were assigned to supergroup B and formed a monophyletic group. The mitochondrial diversity of these populations （ except CC, GZ, TA and TY, N 〈 5 ） was associated with Wolbachia infection. The mtDNA baplotype diversity （Hd） and nucleotide diversity （Pi） of the uninfected group were higher than those in the infected group. Wolbachia infection was significantly negatively correlated with Hd （P 〈 0.05 ）. Furthermore, the analysis of molecular variance （AMOVA） revealed that the genetic differentiation of F. intonsa mtDNA is related to the presence of Wolbachia infection. [ Conclusion ] Genetic differentiation of Wolbachia occurred after infecting host F. intonsa populations. Wolbachia infection is associated with host mtDNA haplotype diversity.