Abstract
<jats:title>ABSTRACT</jats:title>
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<jats:named-content content-type="genus-species">Ostreococcus tauri</jats:named-content>
, a unicellular marine green alga, is the smallest known free-living eukaryote and is ubiquitous in the surface oceans. The ecological success of this organism has been attributed to distinct low- and high-light-adapted ecotypes existing in different niches at a range of depths in the ocean. Viruses have already been characterized that infect the high-light-adapted strains.
<jats:named-content content-type="genus-species">Ostreococcus tauri</jats:named-content>
virus (OtV) isolate OtV-2 is a large double-stranded DNA algal virus that infects a low-light-adapted strain of
<jats:named-content content-type="genus-species">O. tauri</jats:named-content>
and was assigned to the algal virus family
<jats:named-content content-type="genus-species">Phycodnaviridae</jats:named-content>
, genus
<jats:named-content content-type="genus-species">Prasinovirus</jats:named-content>
. Our working hypothesis for this study was that different viruses infecting high- versus low-light-adapted
<jats:named-content content-type="genus-species">O. tauri</jats:named-content>
strains would provide clues to propagation strategies that would give them selective advantages within their particular light niche. Sequence analysis of the 184,409-bp linear OtV-2 genome revealed a range of core functional genes exclusive to this low-light genotype and included a variety of unexpected genes, such as those encoding an RNA polymerase sigma factor, at least four DNA methyltransferases, a cytochrome
<jats:italic>
b
<jats:sub>5</jats:sub>
</jats:italic>
, and a high-affinity phosphate transporter. It is clear that OtV-2 has acquired a range of potentially functional genes from its host, other eukaryotes, and even bacteria over evolutionary time. Such piecemeal accretion of genes is a trademark of large double-stranded DNA viruses that has allowed them to adapt their propagation strategies to keep up with host niche separation in the sunlit layers of the oceanic environment.
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Original language | English |
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Pages (from-to) | 4520-4529 |
Number of pages | 0 |
Journal | Journal of Virology |
Volume | 85 |
Issue number | 9 |
DOIs | |
Publication status | Published - May 2011 |