Australian terrestrial environments harbour extensive RNA virus diversity

ABSTRACT Australia is home to a diverse range of unique native fauna and flora. To address whether Australian ecosystems also harbour unique viruses, we performed meta-transcriptomic sequencing of 16 farmland and sediment samples taken from the east and west coasts of Australia. We identified 2,562 putatively novel viruses across 15 orders, the vast majority of which belonged to the microbe-associated phylum Lenarviricota . In many orders, the novel viruses identified here comprised entirely new clades, such as the Nodamuvirales and Ghabrivirales . Novel viruses also fell between established genera or families, such as in the Cystoviridae and Picornavirales , while highly divergent lineages were identified in the Martellivirales and Ghabrivirales . Viral abundance and alpha diversity were influenced by sampling site, soil type and land use, but not by depth from the surface. In sum, Australian soils and sediments are home to remarkable viral diversity, reflecting the biodiversity of local fauna and flora.