biostudies-literatureBuscaglia MCenter for Dynamic Research on High Latitude Marine EcosystemsCenter for Climate and Resilience ResearchANIDINACHMillennium Institute Center for Genome RegulationCONA-SHOA CIMAR 25Fwrae162https://www.ebi.ac.uk/biostudies/studies/S-EPMC11512752biostudies-literatureUnknown18(1)Microbes in marine ecosystems have evolved their gene content to thrive successfully in the cold. Although this process has been reasonably well studied in bacteria and selected eukaryotes, less is known about the impact of cold environments on the genomes of viruses that infect eukaryotes. Here, we analyzed cold adaptations in giant viruses (Nucleocytoviricota and Mirusviricota) from austral marine environments and compared them with their Arctic and temperate counterparts. We recovered giant virus metagenome-assembled genomes (98 Nucleocytoviricota and 12 Mirusviricota MAGs) from 61 newly sequenced metagenomes and metaviromes from sub-Antarctic Patagonian fjords and Antarctic seawater samples. When analyzing our data set alongside Antarctic and Arctic giant viruses MAGs already depositedThe ISME journalAdaptation strategies of giant viruses to low-temperature marine ecosystems.PMC11512752RT_04-1921190726AUB1900003ANID-FONDAP 1523A0002DG_06–20RT_05–18RT_04–19RT_05-18ANID/FONDAP/151500003DG_06-20ANID-MILENIO-ICN2021_044Buscaglia MSchulz FIriarte JLDiez BfalseAdaptation strategies of giant viruses to low-temperature marine ecosystems.Microbes in marine ecosystems have evolved their gene content to thrive successfully in the cold. Although this process has been reasonably well studied in bacteria and selected eukaryotes, less is known about the impact of cold environments on the genomes of viruses that infect eukaryotes. Here, we analyzed cold adaptations in giant viruses (Nucleocytoviricota and Mirusviricota) from austral marine environments and compared them with their Arctic and temperate counterparts. We recovered giant virus metagenome-assembled genomes (98 Nucleocytoviricota and 12 Mirusviricota MAGs) from 61 newly sequenced metagenomes and metaviromes from sub-Antarctic Patagonian fjords and Antarctic seawater samples. When analyzing our data set alongside Antarctic and Arctic giant viruses MAGs already deposited2024-01-01T00:00:00Z2024 Jan2026-07-15T17:42:09.577Z2026-07-07T03:10:44.203ZS-EPMC115127523917828810.1093/ismejo/wrae162