A novel lineage of myoviruses infecting cyanobacteria is widespread in the oceans

Gazalah Sabehi, Lihi Shaulov, David H. Silver, Itai Yanai, Amnon Harel, Debbie Lindell

Research output: Contribution to journalArticlepeer-review

90 Scopus citations

Abstract

Viruses infecting bacteria (phages) are thought to greatly impact microbial population dynamics as well as the genome diversity and evolution of their hosts. Here we report on the discovery of a novel lineage of tailed dsDNA phages belonging to the family Myoviridae and describe its first representative, S-TIM5, that infects the ubiquitous marine cyanobacterium, Synechococcus. The genome of this phage encodes an entirely unique set of structural proteins not found in any currently known phage, indicating that it uses lineage-specific genes for virion morphogenesis and represents a previously unknown lineage of myoviruses. Furthermore, among its distinctive collection of replication and DNA metabolism genes, it carries a mitochondrial-like DNA polymerase gene, providing strong evidence for the bacteriophage origin of the mitochondrial DNA polymerase. S-TIM5 also encodes an array of bacterial-like metabolism genes commonly found in phages infecting cyanobacteria including photosynthesis, carbon metabolism and phosphorus acquisition genes. This suggests a common gene pool and gene swapping of cyanophage-specific genes among different phage lineages despite distinct sets of structural and replication genes. All cytosines following purine nucleotides are methylated in the S-TIM5 genome, constituting a unique methylation pattern that likely protects the genome from nuclease degradation. This phage is abundant in the Red Sea and S-TIM5 gene homologs are widespread in the oceans. This unusual phage type is thus likely to be an important player in the oceans, impacting the population dynamics and evolution of their primary producing cyanobacterial hosts.

Original languageEnglish
Pages (from-to)2037-2042
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume109
Issue number6
DOIs
StatePublished - 7 Feb 2012
Externally publishedYes

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