Exploring Giant Virus (Nucleocytoviricota) Diversity Across Ecosystems from Viral Metagenomics Data

Abstract

Giant viruses, belonging to the Nucleocytoviricota phylum, are abundant in marine environments but their role in these ecosystems remains largely unexplored. These large-genome viruses are crucial for shaping microbial communities in marine waters, influencing nutrient cycling and ecosystem dynamics. The diversity of giant viruses between two different environment, Southern East China Sea and Kenting National Park, was examined in this study using metagenomics in the through Metagenome Assembled Genome (MAG) analysis, going through the process of assembly, giant virus detection, mapping, sorting, binning, and dereplication. We identified 91 MAGs across four sampling sites. Phylogenetic analysis revealed that Imitervirales was the most abundant order in both environments. Sample 20104 from the Southern East China Sea was the most diverse, hosting two unique orders not found in other samples. Bray-Curtis Dissimilarity metrics indicated similar diversity between Southern East China Sea samples, while Kenting National Park samples were more distinct. Despite similar order-level composition, functional gene analysis showed significant differences between the sites, unique genes involves in signal transduction and immune system genes in the Southern East China Sea and unique fatty acid metabolism genes in Kenting National Park. This highlights giant viruses' distinct composition and function in these environments, emphasizing their role in influencing marine ecosystem health and stability.