Université de Poitiers, Laboratoire Écologie et Biologie des Interactions, UMR CNRS 7267, Équipe Écologie Évolution Symbiose, 40 Avenue du Recteur Pineau, F-86022 Poitiers Cedex, France.
Université de Poitiers, Laboratoire Écologie et Biologie des Interactions, UMR CNRS 7267, Équipe Écologie Évolution Symbiose, 40 Avenue du Recteur Pineau, F-86022 Poitiers Cedex, France.
J Invertebr Pathol. 2014 Feb;116:18-26. doi: 10.1016/j.jip.2013.12.003. Epub 2013 Dec 15.
The alphaproteobacteria Wolbachia pipientis are among the most common and widespread symbionts in the animal world. Their vertical transmission mode is predicted to favour genotypes with low virulence. On the contrary, horizontal transfers of Wolbachia from one host to another have been shown to possibly increase the symbiont virulence. This situation has been previously described when two feminizing Wolbachia strains, wVulC and wVulM, from the ovaries of the woodlouse Armadillidium vulgare were introduced into another woodlouse named Porcellio dilatatus. These two Wolbachia strains induced severe symptoms and eventually caused the death of the recipient host. However, symptoms and death appeared sooner with wVulC than with wVulM. To know whether this difference was due to variation in the dose of infection or a difference in virulence between the two Wolbachia strains, we performed controlled and gradual doses of injection with wVulC and wVulM in P. dilatatus. We showed that the two strains differed intrinsically in their virulence against P. dilatatus and that their virulence is related to the injection dose. Moreover, we showed that wVulC reached higher concentrations in the recipient host than wVulM suggesting a potential link between the bacterial titers and the levels of virulence. We also addressed the impact of the tissue source of the Wolbachia used for the transinfection and demonstrated that Wolbachia transinfected via hemolymph colonized the body of the recipient more quickly and caused accelerated symptoms compared to Wolbachia introduced via a crushed ovaries suspension.
α-变形菌门的沃尔巴克氏体（Wolbachia pipientis）是动物界最常见和分布最广泛的共生体之一。其垂直传播模式预计有利于低毒力基因型。相反，沃尔巴克氏体从一个宿主到另一个宿主的水平转移已被证明可能增加共生体的毒力。当两种来自木虱（Armadillidium vulgare）卵巢的雌性化沃尔巴克氏体菌株 wVulC 和 wVulM 被引入另一种名为 Porcellio dilatatus 的木虱时，就出现了这种情况。这两种沃尔巴克氏体菌株引起了严重的症状，最终导致宿主死亡。然而，wVulC 引起的症状和死亡比 wVulM 更早出现。为了知道这种差异是由于感染剂量的变化还是两种沃尔巴克氏体菌株之间的毒力差异，我们在 P. dilatatus 中用 wVulC 和 wVulM 进行了受控和逐渐剂量的注射。我们表明，这两种菌株在对 P. dilatatus 的毒力方面存在内在差异，并且它们的毒力与注射剂量有关。此外，我们表明 wVulC 在受感染宿主中的浓度高于 wVulM，这表明细菌滴度与毒力水平之间存在潜在联系。我们还研究了用于转染的沃尔巴克氏体的组织来源的影响，并表明通过血淋巴转染的沃尔巴克氏体比通过卵巢粉碎悬浮液转染的沃尔巴克氏体更快地定植受感染宿主的身体，并导致加速的症状。
