title: Marine T4-type bacteriophages, a ubiquitous component of the dark matter of the biosphere.
abstract: Tailed bacteriophages are the most abundant biological entities in marine environments. However, most of these marine phages are uncharacterized because few of their hosts have been cultivated. To learn more about such phages, we designed a set of degenerate PCR primers for phage T4 g23, which encodes the major capsid protein in all of the T4-type phages, an important family of the tailed phage. These primers were used to amplify g23-related sequences from diverse marine environments (fjords and bays of British Columbia, the eastern Gulf of Mexico, and the western Arctic Ocean) revealing a remarkable level of molecular diversity, which in some cases was correlated with morphological variation of the virions. Phylogenetic analysis showed that although some of these sequences were closely related to well studied subgroups of the T4-type phage, such as the T-evens, the majority of them belong to five previously uncharacterized subgroups. These data indicate that the host range of T4-type phages is much broader than previously imagined and that the laboratory isolate T4 belongs to a phage family that is extraordinarily widespread and diverse in the biosphere.
authors.affiliation: Laboratoire de Microbiologie et Génétique Moléculaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5100, 31062, Toulouse, Cedex 9, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Filée
authors.forename: Françoise
authors.initials: F
authors.lastname: Tétart
authors.forename: Curtis A
authors.initials: CA
authors.lastname: Suttle
authors.forename: H M
authors.initials: HM
authors.lastname: Krisch
mesh_terms: D000595:Amino Acid Sequence; D017122:Bacteriophage T4 / Q000235:genetics* / Q000302:isolation & purification*; D001483:Base Sequence; D036022:Capsid Proteins / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D019143:Evolution, Molecular; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012623:Seawater / Q000821:virology; D017386:Sequence Homology, Amino Acid
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral; C064517:gp23 protein, Bacteriophage T4