Biogeography of marine giant viruses reveals their interplay with eukaryotes and ecological functions

Hisashi Endo (1) , Romain Blanc Mathieu (2, 1) , Yanze Li (1) , Guillem Salazar (3) , Nicolas Henry (4) , Karine Labadie (5) , Colomban de Vargas (4) , Matthew B Sullivan (6, 7) , Chris C. Bowler (8, 9) , Patrick Wincker (9, 5) , Lee Karp-Boss (10) , Shinichi Sunagawa (3) , Hiroyuki Ogata (1)

1 Institute for Chemical Research, Kyoto University
2 LPCV - Physiologie cellulaire et végétale
3 Institute of Microbiology and Swiss Institute of Bioinformatics
4 ADMM - Adaptation et diversité en milieu marin
5 GENOSCOPE - Genoscope - Centre national de séquençage [Evry]
6 Department of Microbiology, The Ohio state university
7 Department of Civil, The Ohio State University
8 IBENS - Institut de biologie de l'ENS Paris
9 GOSEE - Global Oceans Systems Ecology & Evolution - Tara Oceans
10 University of Maine - School of Marine Sciences

Analysing a global metagenomic data set from theTaraOceans expeditions, the authors find that the distribution of marine giant virus communities is tightly coupled to that of eukaryotic microorganisms, that these communities are particularly distinct in polar biomes, and that they may sometimes be highly similar both on the surface and at depth. Nucleocytoplasmic large DNA viruses (NCLDVs) are ubiquitous in marine environments and infect diverse eukaryotes. However, little is known about their biogeography and ecology in the ocean. By leveraging theTaraOceans pole-to-pole metagenomic data set, we investigated the distribution of NCLDVs across size fractions, depths and biomes, as well as their associations with eukaryotic communities. Our analyses reveal a heterogeneous distribution of NCLDVs across oceans, and a higher proportion of unique NCLDVs in the polar biomes. The community structures of NCLDV families correlate with specific eukaryotic lineages, including many photosynthetic groups. NCLDV communities are generally distinct between surface and mesopelagic zones, but at some locations they exhibit a high similarity between the two depths. This vertical similarity correlates to surface phytoplankton biomass but not to physical mixing processes, which suggests a potential role of vertical transport in structuring mesopelagic NCLDV communities. These results underscore the importance of the interactions between NCLDVs and eukaryotes in biogeochemical processes in the ocean.

Domaines: Ecologie, Environnement

Hisashi Endo, Romain Blanc Mathieu, Yanze Li, Guillem Salazar, Nicolas Henry, et al.. Biogeography of marine giant viruses reveals their interplay with eukaryotes and ecological functions. Nature Ecology & Evolution, 2020, 4 (12), pp.1639-1649. ⟨10.1038/s41559-020-01288-w⟩. ⟨hal-02974168⟩