title: A novel roseobacter phage possesses features of podoviruses, siphoviruses, prophages and gene transfer agents.
abstract: Bacteria in the Roseobacter lineage have been studied extensively due to their significant biogeochemical roles in the marine ecosystem. However, our knowledge on bacteriophage which infects the Roseobacter clade is still very limited. Here, we report a new bacteriophage, phage DSS3Φ8, which infects marine roseobacter Ruegeria pomeroyi DSS-3. DSS3Φ8 is a lytic siphovirus. Genomic analysis showed that DSS3Φ8 is most closely related to a group of siphoviruses, CbK-like phages, which infect freshwater bacterium Caulobacter crescentus. DSS3Φ8 contains a smaller capsid and has a reduced genome size (146 kb) compared to the CbK-like phages (205-279 kb). DSS3Φ8 contains the DNA polymerase gene which is closely related to T7-like podoviruses. DSS3Φ8 also contains the integrase and repressor genes, indicating its potential to involve in lysogenic cycle. In addition, four GTA (gene transfer agent) genes were identified in the DSS3Φ8 genome. Genomic analysis suggests that DSS3Φ8 is a highly mosaic phage that inherits the genetic features from siphoviruses, podoviruses, prophages and GTAs. This is the first report of CbK-like phages infecting marine bacteria. We believe phage isolation is still a powerful tool that can lead to discovery of new phages and help interpret the overwhelming unknown sequences in the viral metagenomics.
authors.affiliation: Institution of Marine and Environmental Technology, University of Maryland Center for Environmental Science, USA.
authors.forename: Yuanchao
authors.initials: Y
authors.lastname: Zhan
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Sijun
authors.initials: S
authors.lastname: Huang
authors.affiliation: Institute for Microbiology and Genetics. University of Göttingen, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Voget
authors.affiliation: Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Germany.
authors.forename: Meinhard
authors.initials: M
authors.lastname: Simon
authors.affiliation: Institution of Marine and Environmental Technology, University of Maryland Center for Environmental Science, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
mesh_terms: D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism; D016679:Genome, Viral; D008242:Lysogeny; D010802:Phylogeny; D041904:Roseobacter / Q000821:virology*; D017906:Siphoviridae / Q000145:classification / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
chemical_list: D036022:Capsid Proteins