RESUMO
The Red Queen hypothesis posits that antagonistic co-evolution between interacting species results in recurrent natural selection via constant cycles of adaptation and counter-adaptation. Interactions such as these are at their most profound in host-parasite systems, with bacteria and their viruses providing the most intense of battlefields. Studies of bacteriophage evolution thus provide unparalleled insight into the remarkable elasticity of living entities. Here, we report a novel phenomenon underpinning the evolutionary trajectory of a group of dsDNA bacteriophages known as the phiKMVviruses. Employing deep next generation sequencing (NGS) analysis of nucleotide polymorphisms we discovered that this group of viruses generates enhanced intraspecies heterogeneity in their genomes. Our results show the localisation of variants to genes implicated in adsorption processes, as well as variation of the frequency and distribution of SNPs within and between members of the phiKMVviruses. We link error-prone DNA polymerase activity to the generation of variants. Critically, we show trans-activity of this phenomenon (the ability of a phiKMVvirus to dramatically increase genetic variability of a co-infecting phage), highlighting the potential of phages exhibiting such capabilities to influence the evolutionary path of other viruses on a global scale.
Assuntos
Bacteriófagos/genética , DNA Viral/genética , Evolução Molecular , Bacteriófagos/enzimologia , DNA Polimerase Dirigida por DNA/química , DNA Polimerase Dirigida por DNA/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Modelos Moleculares , Fenótipo , Conformação Proteica , Análise de Sequência de DNARESUMO
A complete nucleotide sequence of the new Pseudomonas aeruginosa Luz24likevirus phiCHU was obtained. This virus was shown to have a unique host range whereby it grew poorly on the standard laboratory strain PAO1, but infected 26 of 46 clinical isolates screened, and strains harbouring IncP2 plasmid pMG53. It was demonstrated that phiCHU has single-strand interruptions in its genome. Analysis of the phiCHU genome also suggested that recombination event(s) participated in the evolution of the leftmost portion of the genome, presumably encoding early genes.
