Revisiting evolutionary trajectories and the organization of the < i > Pleolipoviridae < /i > family

by Tomas Alarc ón-Schumacher, Dominik Lücking, Susanne Erdmann Archaeal pleomorphic viruses belonging to thePleolipoviridae family represent an enigmatic group as they exhibit unique genomic features and are thought to have evolved through recombination with different archaeal plasmids. However, most of our understanding of the diversity and evolutionary trajectories of this clade comes from a handful of isolated representatives. Here we present 164 new genomes of pleolipoviruses obtained from metagenomic data of Australian hypersaline lakes and publicly available metagenomic data. We perform a comprehensive analysis on the diversity and evolutionary relationships of the newly discovered viruses and previously described pleolipoviruses. We propose to classify the viruses into five genera within thePleolipoviridae family, with one new genus represented only by virus genomes retrieved in this study. Our data support the current hypothesis that pleolipoviruses reshaped their genomes through recombining with multiple different groups of plasmids, which is reflected in the diversity of their predicted replication strategies. We show that the proposed genusEpsilonpleolipovirus has evolutionary ties to pRN1-like plasmids fromSulfolobus, suggesting that this group could be infecting other archaeal phyla. Interestingly, we observed that the genome size of pleolipoviruses is correlated to the presence or absence of an integrase. Analyses of the host range revealed that all but one v...
Source: PLoS Genetics - Category: Genetics & Stem Cells Authors: Source Type: research