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Philos Trans R Soc Lond B Biol Sci. 2013 Aug 12;368(1626):20130047. doi: 10.1098/rstb.2013.0047. Print 2013 Sep 19.

Functional endogenous viral elements in the genome of the parasitoid wasp Cotesia congregata: insights into the evolutionary dynamics of bracoviruses.

Author information

1
Institut de Recherche sur la Biologie de l'Insecte, CNRS UMR 7261, Université François Rabelais, , Parc de Grandmont, 37200 Tours, France.

Abstract

Bracoviruses represent the most complex endogenous viral elements (EVEs) described to date. Nudiviral genes have been hosted within parasitoid wasp genomes since approximately 100 Ma. They play a crucial role in the wasp life cycle as they produce bracovirus particles, which are injected into parasitized lepidopteran hosts during wasp oviposition. Bracovirus particles encapsidate multiple dsDNA circles encoding virulence genes. Their expression in parasitized caterpillars is essential for wasp parasitism success. Here, we report on the genomic organization of the proviral segments (i.e. master sequences used to produce the encapsidated dsDNA circles) present in the Cotesia congregata parasitoid wasp genome. The provirus is composed of a macrolocus, comprising two-thirds of the proviral segments and of seven dispersed loci, each containing one to three segments. Comparative genomic analyses with closely related species gave insights into the evolutionary dynamics of bracovirus genomes. Conserved synteny in the different wasp genomes showed the orthology of the proviral macrolocus across different species. The nudiviral gene odv-e66-like1 is conserved within the macrolocus, suggesting an ancient co-localization of the nudiviral genome and bracovirus proviral segments. By contrast, the evolution of proviral segments within the macrolocus has involved a series of lineage-specific duplications.

KEYWORDS:

bracovirus; comparative genomics; obligatory mutualism; parasitoid wasp; polydnavirus

PMID:
23938757
PMCID:
PMC3758192
DOI:
10.1098/rstb.2013.0047
[Indexed for MEDLINE]
Free PMC Article

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