title: Contributions of P2- and P22-like prophages to understanding the enormous diversity and abundance of tailed bacteriophages.
abstract: We identified 9371 tailed phage prophages of 20 known types in reported complete genome sequences of 3298 bacteria in the Salmonella genus. These include 4758 P2 type and 744 P22 type prophages. The latter prophage types were found in the genome sequences of 127 and 24 bacterial host genera, increasing the known host ranges of phages in these groups by 114 and 20 genera, respectively. These prophage nucleotide sequences displayed much more diversity than was previously known from the 48 P2 and 24 P22 type authentic phages whose genomes have been sequenced. More detailed analysis of these prophage sequences indicated that major capsid protein (MCP) gene exchange between tailed phage clusters or types is extremely rare and that P22 prophage-encoded tailspikes correspond perfectly with their hosts' surface polysaccharide structure; thus, MCP and tailspike sequences accurately predict tailed phage type (and thus lifestyle) and host cell surface polysaccharide structure, respectively.
authors.affiliation: Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, University of Utah, Salt Lake City, UT 84112, United States; Department of Biology, University of Utah, Salt Lake City, UT 84112, United States. Electronic address: sherwood.casjens@path.utah.edu.
authors.forename: Sherwood R
authors.initials: SR
authors.lastname: Casjens
authors.affiliation: Microbiology and Molecular Biology Department, Brigham Young University, Provo, UT 84602, United States. Electronic address: Julianne_Grose@byu.edu.
authors.forename: Julianne H
authors.initials: JH
authors.lastname: Grose
mesh_terms: D001433:Bacteriolysis; D044822:Biodiversity; D016000:Cluster Analysis; D004755:Enterobacteriaceae / Q000235:genetics / Q000821:virology; D015321:Gene Rearrangement; D016680:Genome, Bacterial; D016679:Genome, Viral; D058507:Host Specificity; D010802:Phylogeny; D039002:Prophages / Q000145:classification* / Q000235:genetics*; D011995:Recombination, Genetic
keywords: Bacteriophage; Caudovirales; Major capsid protein; Phage P2; Phage P22; Prophage; Salmonella; Tailed phage; Tailspike