Name: Karyna Rosario

Email: krosariocora@gmail.com

Author: Karyna Rosario*, Kim Pause, and Mya Breitbart

Author affiliation: College of Marine Science, University of South Florida, St. Petersburg, FL *Presenting author

Abstract title: Novel single-stranded DNA viruses in the marine environment

Absstract:

Little is known about single-stranded DNA (ssDNA) eukaryotic viruses in the marine environment. The incorporation of multiple displacement amplification (MDA) into metagenomic analyses provides a method to detect ssDNA viruses in environmental viral communities. Furthermore, MDA can be used to enrich for ssDNA circular genomes. The present study identified circular ssDNA viruses in the marine environment through "mining" of public viral metagenomic datasets generated with an MDA step. This analysis revealed the presence of viruses similar to ssDNA circoviruses in metagenomic libraries from different marine environments: the Chesapeake Bay, British Columbia coastal waters, and the Sargasso Sea. DNA samples from viral concentrates from these regions were used to verify metagenomic sequence assemblies and complete circovirus-like genomes through PCR. Five novel circo-like genomes, ranging in size from 1740 to 2577 nt, were constructed from these libraries. All the genomes contained two major ORFs, one with similarities to the replication protein (Rep) of circoviruses (~ 30% amino acid level identity), and an unknown ORF that may encode for a structural protein. Although all the genomes had similarities to the Rep of circoviruses, only two had genomic features consistent with known circoviruses. The low similarities to known circovirus Rep proteins and novel genome architectures suggest these viruses belong to new genera and/or families of circular ssDNA viruses. Preliminary data indicates that Chesapeake Bay circoviruses are present in a range of salinities (7 - 25 psu) and ssDNA viruses in the Sargasso Sea are present throughout the water column (40 m - 120 m). The identification of circovirus-like genomes in three different locations at a wide range of salinities and depths suggests that small eukaryotic ssDNA viruses are more abundant in the marine environment than previously thought. Future studies need to explore the host range and ecology of these novel viruses.