%0 Journal Article %J BMC Evolutionary Biology %D 2014 %T Cophylogenetic interactions between marine viruses and eukaryotic picophytoplankton %A Bellec, Laure %A Clerissi, Camille %A Edern, Roseline %A Foulon, Elodie %A Simon, Nathalie %A Grimsley, Nigel %A Desdevises, Yves %K rcc %K RCC1105 %K rcc1107 %K RCC1108 %K RCC1109 %K RCC114 %K RCC2482 %K RCC2483 %K RCC2484 %K RCC2485 %K RCC344 %K RCC356 %K RCC373 %K RCC418 %K RCC461 %K RCC464 %K RCC465 %K RCC629 %K RCC658 %K RCC745 %K RCC789 %K RCC834 %K SBR$_\textrmP$hyto$_\textrmD$PO %X BACKGROUND:Numerous studies have investigated cospeciation (or cophylogeny) in various host-symbiont systems, and different patterns were inferred, from strict cospeciation where symbiont phylogeny mirrors host phylogeny, to complete absence of correspondence between trees. The degree of cospeciation is generally linked to the level of host specificity in the symbiont species and the opportunity they have to switch hosts. In this study, we investigated cophylogeny for the first time in a microalgae-virus association in the open sea, where symbionts are believed to be highly host-specific but have wide opportunities to switch hosts. We studied prasinovirus-Mamiellales associations using 51 different viral strains infecting 22 host strains, selected from the characterisation and experimental testing of the specificities of 313 virus strains on 26 host strains.RESULTS:All virus strains were restricted to their host genus, and most were species-specific, but some of them were able to infect different host species within a genus. Phylogenetic trees were reconstructed for viruses and their hosts, and their congruence was assessed based on these trees and the specificity data using different cophylogenetic methods, a topology-based approach, Jane, and a global congruence method, ParaFit. We found significant congruence between virus and host trees, but with a putatively complex evolutionary history.CONCLUSIONS:Mechanisms other than true cospeciation, such as host-switching, might explain a part of the data. It has been observed in a previous study on the same taxa that the genomic divergence between host pairs is larger than between their viruses. It implies that if cospeciation predominates in this algae-virus system, this would support the hypothesis that prasinoviruses evolve more slowly than their microalgal hosts, whereas host switching would imply that these viruses speciated more recently than the divergence of their host genera. %B BMC Evolutionary Biology %V 14 %P 59 %G eng %U http://www.biomedcentral.com/1471-2148/14/59 %R 10.1186/1471-2148-14-59 %0 Journal Article %J Applied and Environmental Microbiology %D 2014 %T Unveiling of the diversity of prasinoviruses (phycodnaviridae) in marine samples by using high-throughput sequencing analyses of PCR-Amplified DNA polymerase and major capsid protein genes %A Clerissi, Camille %A Grimsley, Nigel %A Ogata, Hiroyuki %A Hingamp, Pascal %A Poulain, Julie %A Desdevises, Yves %K Micromonas %K rcc %K TARA-Oceans %X Viruses strongly influence the ecology and evolution of their eukaryotic hosts in the marine environment, but little is known about their diversity and distribution. Prasinoviruses infect an abundant and widespread class of phytoplankton, the Mamiellophyceae, and thereby exert a specific and important role in microbial ecosystems. However, molecular tools to specifically identify this viral genus in environmental samples are still lacking. We developed two primer sets, designed for use with polymerase chain reactions and 454 pyrosequencing technologies, to target two conserved genes, encoding the DNA polymerase (PolB gene) and the major capsid protein (MCP gene). While only one copy of the PolB gene is present in Prasinovirus genomes, there are at least seven paralogs for MCP, the copy we named number 6 being shared with other eukaryotic alga-infecting viruses. Primer sets for PolB and MCP6 were thus designed and tested on 6 samples from the Tara Oceans project. The results suggest that the MCP6 amplicons show greater richness but that PolB gave a wider coverage of Prasinovirus diversity. As a consequence, we recommend use of the PolB primer set, which will certainly reveal exciting new insights about the diversity and distribution of prasinoviruses at the community scale. %B Applied and Environmental Microbiology %V 80 %P 3150–3160 %G eng %U http://aem.asm.org/content/80/10/3150.abstract %R 10.1128/aem.00123-14 %0 Journal Article %J Journal of Virology %D 2012 %T Prasinoviruses of the marine green alga Ostreococcus tauri are mainly species specific %A Clerissi, Camille %A Desdevises, Yves %A Grimsley, Nigel %K rcc %K RCC1110 %K RCC1114 %K RCC1115 %K RCC1116 %K RCC1117 %K RCC1123 %K RCC1558 %K RCC1561 %K RCC745 %X Prasinoviruses infecting unicellular green algae in the order Mamiellales (class Mamiellophyceae) are commonly found in coastal marine waters where their host species frequently abound. We tested 40 Ostreococcus tauri viruses on 13 independently isolated wild-type O. tauri strains, 4 wild-type O. lucimarinus strains, 1 Ostreococcus sp. (“Ostreococcus mediterraneus”) clade D strain, and 1 representative species of each of two other related species of Mamiellales, Bathycoccus prasinos and Micromonas pusilla. Thirty-four out of 40 viruses infected only O. tauri, 5 could infect one other species of the Ostreococcus genus, and 1 infected two other Ostreococcus spp., but none of them infected the other genera. We observed that the overall susceptibility pattern of Ostreococcus strains to viruses was related to the size of two host chromosomes known to show intraspecific size variations, that genetically related viruses tended to infect the same host strains, and that viruses carrying inteins were strictly strain specific. Comparison of two complete O. tauri virus proteomes revealed at least three predicted proteins to be candidate viral specificity determinants. %B Journal of Virology %V 86 %P 4611–4619 %G eng %U http://jvi.asm.org/content/86/8/4611.abstract %R 10.1128/jvi.07221-11