Symbiotic Virus at the Evolutionary Intersection of Three Types of Large DNA Viruses; Iridoviruses, Ascoviruses, and Ichnoviruses
Open Access
- 28 July 2009
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 4 (7), e6397
- https://doi.org/10.1371/journal.pone.0006397
Abstract
The ascovirus, DpAV4a (family Ascoviridae), is a symbiotic virus that markedly increases the fitness of its vector, the parasitic ichneumonid wasp, Diadromus puchellus, by increasing survival of wasp eggs and larvae in their lepidopteran host, Acrolepiopsis assectella. Previous phylogenetic studies have indicated that DpAV4a is related to the pathogenic ascoviruses, such as the Spodoptera frugiperda ascovirus 1a (SfAV1a) and the lepidopteran iridovirus (family Iridoviridae), Chilo iridescent virus (CIV), and is also likely related to the ancestral source of certain ichnoviruses (family Polydnaviridae). To clarify the evolutionary relationships of these large double-stranded DNA viruses, we sequenced the genome of DpAV4a and undertook phylogenetic analyses of the above viruses and others, including iridoviruses pathogenic to vertebrates. The DpAV4a genome consisted of 119,343 bp and contained at least 119 open reading frames (ORFs), the analysis of which confirmed the relatedness of this virus to iridoviruses and other ascoviruses. Analyses of core DpAV4a genes confirmed that ascoviruses and iridoviruses are evolutionary related. Nevertheless, our results suggested that the symbiotic DpAV4a had a separate origin in the iridoviruses from the pathogenic ascoviruses, and that these two types shared parallel evolutionary paths, which converged with respect to virion structure (icosahedral to bacilliform), genome configuration (linear to circular), and cytopathology (plasmalemma blebbing to virion-containing vesicles). Our analyses also revealed that DpAV4a shared more core genes with CIV than with other ascoviruses and iridoviruses, providing additional evidence that DpAV4a represents a separate lineage. Given the differences in the biology of the various iridoviruses and ascoviruses studied, these results provide an interesting model for how viruses of different families evolved from one another.Keywords
This publication has 42 references indexed in Scilit:
- Ubiquitin and ubiquitin-like specific proteases targeted by infectious pathogens: Emerging patterns and molecular principlesBiochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 2008
- An Insect Virus-Encoded MicroRNA Regulates Viral ReplicationJournal of Virology, 2008
- Genome Analysis of a Glossina pallidipes Salivary Gland Hypertrophy Virus Reveals a Novel, Large, Double-Stranded Circular DNA VirusJournal of Virology, 2008
- Modulation of natural killer cells by human cytomegalovirusJournal of Clinical Virology, 2008
- Marine mimivirus relatives are probably large algal virusesVirology Journal, 2008
- Molecular evidence for the evolution of ichnoviruses from ascoviruses by symbiogenesisBMC Evolutionary Biology, 2008
- Genomic and Morphological Features of a Banchine Polydnavirus: Comparison with Bracoviruses and IchnovirusesJournal of Virology, 2007
- Genomic Sequence of Spodoptera frugiperda Ascovirus 1a , an Enveloped, Double-Stranded DNA Insect Virus That Manipulates Apoptosis for Viral ReproductionJournal of Virology, 2006
- Genome of Invertebrate Iridescent Virus Type 3 (Mosquito Iridescent Virus)Journal of Virology, 2006
- Cryo-electron Microscopy of the Giant MimivirusJournal of Molecular Biology, 2005