Wolbachia infect ovaries in the course of their maturation: last minute passengers and priority travellers?

PLoS One. 2014 Apr 10;9(4):e94577. doi: 10.1371/journal.pone.0094577. eCollection 2014.

Abstract

Wolbachia are widespread endosymbiotic bacteria of arthropods and nematodes. Studies on such models suggest that Wolbachia's remarkable aptitude to infect offspring may rely on a re-infection of ovaries from somatic tissues instead of direct cellular segregation between oogonia and oocytes. In the terrestrial isopod Armadillidium vulgare, Wolbachia are vertically transmitted to the host offspring, even though ovary cells are cyclically renewed. Using Fluorescence in situ hybridization (FISH), we showed that the proportion of infected oocytes increased in the course of ovary and oocyte maturation, starting with 31.5% of infected oocytes only. At the end of ovary maturation, this proportion reached 87.6% for the most mature oocytes, which is close to the known transmission rate to offspring. This enrichment can be explained by a secondary acquisition of the bacteria by oocytes (Wolbachia can be seen as last minute passengers) and/or by a preferential selection of oocytes infected with Wolbachia (as priority travellers).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Load
  • Cell Size
  • Female
  • Host-Pathogen Interactions
  • In Situ Hybridization, Fluorescence
  • Isopoda / growth & development
  • Isopoda / microbiology*
  • Oocytes / growth & development
  • Oocytes / microbiology*
  • Ovary / growth & development
  • Ovary / microbiology*
  • Wolbachia / physiology*

Grants and funding

Financial support was provided by the CNRS, The University of Poitiers, the ANR ImmunSymbArt (ANR-10-BLAN-1701, coordinator D. Bouchon) and ADaWOL (ANR-09-JCJC-0109-01, coordinator M. Sicard). The authors thank the confocal microscopy facility from at the University of Poitiers (ImageUP), and the CPER Eco-Industrie as well as the Région Poitou-Charentes for their participation in funding of the Apotome microscope. The work of L. Genty was funded by a PhD fellowship from the French Ministère de l'Education Nationale, de l'Enseignement Supérieur et de la Recherche. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.