Taxonomy of bacterial viruses: Establishment of tailed virus genera and the order Caudovirales

Abstract

Bacterial viruses have been classified into 13 families and 1 unassigned genus. A new order, CaudoviraIes, has now been established, comprising the three families of tailed bacterial viruses, based on similarities in tailed virus morphology, replication, and assembly. In addition, genera have been established for some species in each tailed virus family, based on properties involving viral DNA replication and packaging, and on some features specific to particular genera (e.g., DNA-termini linked proteins, virus-encoded polymerases, and ability to establish temperate infections). At present, there are six genera in the family Myoviridae (viruses with contractile tails), six in the family Siphoviridae (viruses with long, noncontractile tails), and three in the family Podoviridae (viruses with short noncontractile tails). In recognition that the definitions of tailed virus genera represent a 'work in progress' and to keep the nomenclature flexible, tailed virus genera have been assigned vernacular names based on their type species.