Giant virus communities from Antarctic and sub-Antarctic marine waters (shotgun metagenomics)

In this study, 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. Comparative analysis with Arctic and Antarctic MAGs revealed that polar giant viruses dominate sub-10 degrees C waters and harbor distinct phylotypes, while Patagonian counterparts span broader thermal ranges with lower endemicity. Despite distributional differences, cold-adapted viruses across these regions exhibit convergent genomic and proteomic adaptations likely vulnerable to climate-driven biodiversity loss.