Virophage control of antarctic algal host-virus dynamics

Sheree Yau, Federico M. Lauro, Matthew Z. DeMaere, Mark V. Brown, Torsten Thomas, Mark J. Raftery, Cynthia Andrews-Pfannkoch, Matthew Lewis, Jeffrey M. Hoffman, John A. Gibson, Ricardo Cavicchioli*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

222 Citations (Scopus)


es are abundant ubiquitous members of microbial communities and in the marine environment affect population structure and nutrient cycling by infecting and lysing primary producers. Antarctic lakes are microbially dominated ecosystems supporting truncated food webs in which viruses exert a major influence on the microbial loop. Here we report the discovery of a virophage (relative of the recently described Sputnik virophage) that preys on phycodnaviruses that infect prasinophytes (phototrophic algae). By performing metaproteogenomic analysis on samples from Organic Lake, a hypersaline meromictic lake in Antarctica, complete virophage and near-complete phycodnavirus genomes were obtained. By introducing the virophage as an additional predator of a predator-prey dynamic model we determined that the virophage stimulates secondary production through the microbial loop by reducing overall mortality of the host and increasing the frequency of blooms during polar summer light periods. Virophages remained abundant in the lake 2 y later and were represented by populations with a high level of major capsid protein sequence variation (25-100% identity). Virophage signatures were also found in neighboring Ace Lake (in abundance) and in two tropical lakes (hypersaline and fresh), an estuary, and an ocean upwelling site. These findings indicate that virophages regulate host-virus interactions, influence overall carbon flux in Organic Lake, and play previously unrecognized roles in diverse aquatic ecosystems.

Original languageEnglish
Pages (from-to)6163-6168
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number15
Publication statusPublished - 12 Apr 2011
Externally publishedYes


  • East Antarctica
  • Metagenomics
  • Metaproteomics
  • Microbial ecology
  • Vestfold Hills


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