Genomes of unknown marine viruses
RNA viruses have been isolated that infect marine organisms ranging from bacteria to whales, but little is known about the composition and population structure of the in situ marine RNA virus community. In a recent study, the majority of three genomes of previously unknown positive-sense single-stranded (ss) RNA viruses were assembled from reverse-transcribed whole-genome shotgun libraries. The present contribution comparatively analyzes these genomes with respect to representative viruses from established virus taxa. Two of the genomes appear to be polycistronic viruses in the proposed order Picornavirales that fall into a well-supported group of marine picorna-like viruses, the characterized members of which all infect marine protists. A temporal and geographic survey indicates that some of these virus genomes are persistent and widespread in British Columbia waters. The third genome encodes a putative RNA-dependent RNA polymerase (RdRp) that is related to the RdRp of viruses in the family Tombusviridae, but the remaining SOG sequence has no significant similarity to any sequences in the NCBI database. The complete genomes of these viruses permitted analyses that resulted in a more comprehensive comparison of these pathogens with established taxa.
