Diversity of viruses infecting the green micro-alga XXXX .

@entity281 @entity71308 @entity60181
UNASSIGNED: The functional diversity of eukaryotic viruses infecting a single host strain from seawater samples originating from distant marine locations is unknown. To estimate this diversity, we used lysis plaque assays to detect viruses that infect the widespread species @entity71308 , which is found in coastal and mesotrophic systems, and @entity60181 , which was isolated from coastal and lagoon sites from the NW Mediterranean Sea. Detection of viral lytic activities against @entity60181 was not observed using seawater from most sites, except those close to the area where the host strain was isolated. In contrast, the more cosmopolitan @entity71308 species recovered viruses from locations in the Atlantic and Pacific Oceans and the Mediterranean Sea. Six new @entity71308 viruses (OlVs) were then characterized and their genomes sequenced. Two subgroups of OlVs were distinguished based on their genetic distances and on the inversion of a central 32 kb long DNA fragment, but overall their genomes displayed a high level of synteny. The two groups did not correspond to proximity of isolation sites and the phylogenetic distance between these subgroups was higher than the distances observed among viruses infecting @entity60181 . Our study demonstrates that viruses originating from very distant sites are able to infect the same algal host strain and can be more diverse than those infecting different species of the same genus. Finally, distinctive features and evolutionary distances between these different viral subgroups does not appear to be linked to biogeography of the viral isolates. IMPORTANCE: Marine eukaryotic phytoplankton virus diversity has yet to be addressed and, more specifically, it is unclear whether diversity is connected to geographical distance and whether @entity281 and lysis patterns exist among such viruses that infect the same host strain. Here, we assessed the genetic distance of geographically segregated viruses that infect the ubiquitous green microalga @entity60181 . This study provides the first glimpse into the diversity of predicted gene functions in @entity60181 viruses originating from distant sites and provide new insights to potential host-distributions and restrictions in the world oceans.
