Viral Diversity of Coastal Restinga Soils From Southern Brazil.

Coastal ecotones are highly dynamic environments for viral studies due to their extreme abiotic conditions, transitional nature between marine and terrestrial domains and high biodiversity. In Brazil, the Restinga is a coastal ecotone along the shoreline, characterized by nutrient-poor sandy soils, high salinity, strong winds and intense solar radiation, hosting poorly explored microbial communities essential for ecological balance. This exploratory study provides a preliminary characterization of viral diversity across three Restinga localities in southern Brazil (Imbé, Cidreira and Mostardas) using metagenomics. We identified 261 viral families, 2023 genera and 6064 species, with 'Unknown' representing 44%-46% of families and ~9% of genera. Among known taxa, Mimiviridae was most frequent (15%-16%), followed by Phycodnaviridae (9%), Peduoviridae (5%) and Kyanoviridae (4%-5%). Genera such as Tupanvirus and Fadolivirus were abundant (~5%), with Fadolivirus algeromassiliense and Donellivirus gee among the most frequent species. Although alpha diversity and composition did not differ significantly among sites, landscape features influenced viral communities. Viral richness and abundance increased with urban land cover and isolation but decreased with Restinga cover and patch fragmentation.