Université de Lyon; Université Lyon 1; CNRS; UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, 43 Boulevard du 11 Novembre 1918, Villeurbanne F-69622, FranceLaboratoire d'Entomologie Fondamentale et Appliquée, Département de Biologie et Physiologie Animales, Université de Ouagadougou, 03 BP 7021 Ouagadougou 03CIRAD, UMR BGPI, TA A54/K, Campus International de Baillarguet, Montpellier Cedex, FranceThe Agricultural Research Organization (ARO), Department of Entomology, Newe Ya'ar Research Center, PO Box 1021, Ramat Yishay 30095, IsraelDepartment of Evolutionary and Environmental Biology, University of Haifa, Haifa, IsraelThe Agricultural Research Organization (ARO), Department of Entomology, Volcani Center, PO Box 6, Bet-Dagan 50250, Israel.
Mol Ecol. 2010 Oct;19(19):4365-76. doi: 10.1111/j.1365-294X.2010.04775.x. Epub 2010 Aug 18.
Bemisia tabaci, an invasive pest that causes crop damage worldwide, is a highly differentiated species complex, divided into biotypes that have mainly been defined based on mitochondrial DNA sequences. Although endosymbionts can potentially induce population differentiation, specialization and indirect selection on mtDNA, studies have largely ignored these influential passengers in B. tabaci, despite as many as seven bacterial endosymbionts have been identified. Here, we investigate the composition of the whole bacterial community in worldwide populations of B. tabaci, together with host genetic differentiation, focusing on the invasive B and Q biotypes. Among 653 individuals studied, more than 95% of them harbour at least one secondary endosymbiont, and multiple infections are very common. In addition, sequence analyses reveal a very high diversity of facultative endosymbionts in B. tabaci, with some bacterial genus being represented by more than one strain. In the B and Q biotypes, nine different strains of bacteria have been identified. The mtDNA-based phylogeny of B. tabaci also reveals a very high nucleotide diversity that partitions the two ITS clades (B and Q) into six CO1 genetic groups. Each genetic group is in linkage disequilibrium with a specific combination of endosymbionts. All together, our results demonstrate the rapid dynamics of the bacterial endosymbiont-host associations at a small evolutionary scale, questioning the role of endosymbiotic communities in the evolution of the Bemisia tabaci species complex and strengthening the need to develop a metacommunity theory of inherited endosymbionts.
烟粉虱，一种对全世界作物造成损害的入侵害虫，是一个高度分化的物种复合体，根据线粒体 DNA 序列主要分为生物型。尽管内共生菌可能会在烟粉虱种群分化、特化和对 mtDNA 的间接选择中产生影响，但尽管已经鉴定出多达 7 种细菌内共生菌，这些有影响力的乘客在烟粉虱中的研究却在很大程度上被忽视了。在这里，我们研究了全世界烟粉虱种群中整个细菌群落的组成，以及宿主遗传分化，重点研究了入侵的 B 和 Q 生物型。在所研究的 653 个个体中，超过 95%的个体至少携带一种次生内共生菌，并且多重感染非常普遍。此外，序列分析揭示了烟粉虱中兼性内共生菌的高度多样性，一些细菌属由不止一个菌株代表。在 B 和 Q 生物型中，已经鉴定出 9 种不同的细菌菌株。烟粉虱的 mtDNA 系统发育也揭示了非常高的核苷酸多样性，将两个 ITS 枝（B 和 Q）分为 6 个 CO1 遗传群。每个遗传群与特定的共生菌组合呈连锁不平衡。总的来说，我们的研究结果表明，在小进化尺度上，细菌内共生体-宿主的关联具有快速的动态性，这质疑了内共生菌群在烟粉虱物种复合体进化中的作用，并加强了需要发展一个继承内共生体的元社区理论。
