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Presenter: Vartika Burman

Faculty Sponsor: Jeffrey Blanchard

School: UMass Amherst

Research Area: Genetics

Session: Poster Session 6, 4:15 PM - 5:00 PM, Auditorium, A80

ABSTRACT

Virophages are a group of double-stranded DNA viruses that hijack the replicative machinery of giant viruses (GVs), limiting their overall DNA replication and gene expression. So far, they have been primarily studied in aquatic environments and little is known about their role in soil ecosystems. To bridge this gap in research, 33 different virophage viral operational taxonomic units (vOTUs) were discovered from the Barre Woods soil warming experiment with one vOTU existing solely in the heated plot with significant overrepresentation (p = 0.00029). We termed this vOTU “Imagivirus” since a majority of its identified proteins are hypothetical. Apart from these hypothetical proteins, four major conserved genes: major and minor capsid, cysteine protease, and ATPase, were identified across all vOTUs. Phylogenetic analysis using conserved genes in high quality genomes and from reference virophage genomes show Imagivirus genomes forming a distinct clade. Virophages are surprisingly abundant in soil samples, compared to the limited collection of GVs and protists. The purpose of this study is to examine this relative abundance of virophages and better understand their significance in the soil microbiome. A similar overrepresentation of a potential protist host or giant virus in warming plots samples was not detected and hence, the virophage may exist as free particles in the soil or more numerically abundant replicons inside a host cell.