Viral Ecogenomics of Arctic Cryopeg Brine and Sea Ice.

Autor:	Zhong ZP; Byrd Polar and Climate Research Center, The Ohio State University, Columbus, Ohio, USA.; Department of Microbiology, The Ohio State University, Columbus, Ohio, USA., Rapp JZ; School of Oceanography, University of Washington, Seattle, Washington, USA., Wainaina JM; Department of Microbiology, The Ohio State University, Columbus, Ohio, USA., Solonenko NE; Department of Microbiology, The Ohio State University, Columbus, Ohio, USA., Maughan H; Ronin Institute, Montclair, New Jersey, USA., Carpenter SD; School of Oceanography, University of Washington, Seattle, Washington, USA., Cooper ZS; School of Oceanography, University of Washington, Seattle, Washington, USA., Jang HB; Department of Microbiology, The Ohio State University, Columbus, Ohio, USA., Bolduc B; Department of Microbiology, The Ohio State University, Columbus, Ohio, USA., Deming JW; School of Oceanography, University of Washington, Seattle, Washington, USA jdeming@uw.edu sullivan.948@osu.edu., Sullivan MB; Byrd Polar and Climate Research Center, The Ohio State University, Columbus, Ohio, USA jdeming@uw.edu sullivan.948@osu.edu.; Department of Microbiology, The Ohio State University, Columbus, Ohio, USA.; Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, Ohio, USA.; Center of Microbiome Science, The Ohio State University, Columbus, Ohio, USA.
Jazyk:	angličtina
Zdroj:	MSystems [mSystems] 2020 Jun 16; Vol. 5 (3). Date of Electronic Publication: 2020 Jun 16.
DOI:	10.1128/mSystems.00246-20
Abstrakt:	Arctic regions, which are changing rapidly as they warm 2 to 3 times faster than the global average, still retain microbial habitats that serve as natural laboratories for understanding mechanisms of microbial adaptation to extreme conditions. Seawater-derived brines within both sea ice (sea-ice brine) and ancient layers of permafrost (cryopeg brine) support diverse microbes adapted to subzero temperatures and high salinities, yet little is known about viruses in these extreme environments, which, if analogous to other systems, could play important evolutionary and ecosystem roles. Here, we characterized viral communities and their functions in samples of cryopeg brine, sea-ice brine, and melted sea ice. Viral abundance was high in cryopeg brine (1.2 × 10 8  ml -1 ) and much lower in sea-ice brine (1.3 × 10 5 to 2.1 × 10 5  ml -1 ), which roughly paralleled the differences in cell concentrations in these samples. Five low-input, quantitative viral metagenomes were sequenced to yield 476 viral populations (i.e., species level; ≥10 kb), only 12% of which could be assigned taxonomy by traditional database approaches, indicating a high degree of novelty. Additional analyses revealed that these viruses: (i) formed communities that differed between sample type and vertically with sea-ice depth; (ii) infected hosts that dominated these extreme ecosystems, including Marinobacter , Glaciecola , and Colwellia ; and (iii) encoded fatty acid desaturase ( FAD ) genes that likely helped their hosts overcome cold and salt stress during infection, as well as mediated horizontal gene transfer of FAD genes between microbes. Together, these findings contribute to understanding viral abundances and communities and how viruses impact their microbial hosts in subzero brines and sea ice. IMPORTANCE This study explores viral community structure and function in remote and extreme Arctic environments, including subzero brines within marine layers of permafrost and sea ice, using a modern viral ecogenomics toolkit for the first time. In addition to providing foundational data sets for these climate-threatened habitats, we found evidence that the viruses had habitat specificity, infected dominant microbial hosts, encoded host-derived metabolic genes, and mediated horizontal gene transfer among hosts. These results advance our understanding of the virosphere and how viruses influence extreme ecosystems. More broadly, the evidence that virally mediated gene transfers may be limited by host range in these extreme habitats contributes to a mechanistic understanding of genetic exchange among microbes under stressful conditions in other systems. (Copyright © 2020 Zhong et al.)
Databáze:	MEDLINE
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