Molecular and Microscopic Evidence of Viruses in Marine Copepods

Darren Dunlap, Terry Fei Fan Ng, Karyna Rosario, Jorge Barbosa, Anthony Greco, Mya Breitbart, Ian Hewson

Research output: Contribution to journalArticlepeer-review

Abstract

<p> <p id="x-x-p-4"> As dominant members of marine mesozooplankton communities, copepods play critical roles in oceanic food webs and biogeochemical cycling. Despite the ecological significance of copepods, little is known regarding the causes of copepod mortality, and up to 35% of total copepod mortality cannot be accounted for by predation alone. Viruses have been established as ecologically important infectious agents in the oceans; however, viral infection has not been investigated in mesozooplankton communities. Here we used molecular and microscopic techniques to document viral infection in natural populations of the calanoid copepods <em> Acartia tonsa </em> (Dana) and <em> Labidocera aestiva </em> (Wheeler) in Tampa Bay, FL. Viral metagenomics revealed previously undocumented viruses in each species, named <em> Acartia tonsa </em> copepod circo-like virus (AtCopCV) and <em> Labidocera aestiva </em> copepod circo-like virus (LaCopCV). LaCopCV was found to be extremely prevalent and abundant in <em> L. aestiva </em> populations, with up to 100% prevalence in some samples and average viral loads of 1.13 &times; 10 <sup> 5 </sup> copies per individual. LaCopCV transcription was also detected in the majority of <em> L. aestiva </em> individuals, indicating viral activity. AtCopCV was sporadically detected in <em> A. tonsa </em> populations year-round, suggesting temporal variability in viral infection dynamics. Finally, virus-like particles of unknown identity were observed in the connective tissues of <em> A. tonsa </em> and <em> L. aestiva </em> by transmission electron microscopy, demonstrating that viruses were actively proliferating in copepod connective tissue as opposed to infecting gut contents, parasites, or symbionts. Taken together, these results provide strong independent lines of evidence for active viral infection in dominant copepod species, indicating that viruses may significantly influence mesozooplankton ecology. </p></p>
Original languageAmerican English
JournalProceedings of the National Academy of Sciences USA
Volume110
DOIs
StatePublished - Jan 1 2013

Keywords

  • circovirus
  • zooplankton
  • crustacea
  • ssDNA virus

Disciplines

  • Life Sciences

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