Caudovirales

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Caudoviricetes
T Bacteriophages 2024.tif
Order Caudovirales. Structures of T Bacteriophages representing the seven T types of Escherichia coli phages described by Max Delbruck in the 1940s. T4 of the Myoviridae family, T5 of the Siphoviridae family, and T7 of the Podoviridae family. The structures were built from individual protein data bank (pdb) files in the UCSF Chimera software, which were updated to the year 2024 and at real scale.
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Duplodnaviria
Kingdom: Heunggongvirae
Phylum: Uroviricota
Class:Caudoviricetes
Subdivisions

See text

Tailed bacteriophage structure: (1) head, (2) tail, (3) DNA, (4) capsid, (5) collar, (6) sheath, (7) tail fibres, (8) spikes, (9) base plate Bacteriophage structure.png
Tailed bacteriophage structure: (1) head, (2) tail, (3) DNA, (4) capsid, (5) collar, (6) sheath, (7) tail fibres, (8) spikes, (9) base plate
Transmission electron micrograph of Gamma-Phage Gamma phage.png
Transmission electron micrograph of Gamma-Phage
Illustrations of various Caudovirales. Not to scale. Ben Darby Caudovirales illustrations.png
Illustrations of various Caudovirales. Not to scale.

Caudoviricetes is a class of viruses known as the tailed bacteriophages (cauda is Latin for "tail"). [1] Under the Baltimore classification scheme, the Caudoviricetes are group I viruses as they have double stranded DNA (dsDNA) genomes, which can be anywhere from 18,000 base pairs to 500,000 base pairs in length. [2] The virus particles have a distinct shape; each virion has an icosahedral head that contains the viral genome, and is attached to a flexible tail by a connector protein. [2] The order encompasses a wide range of viruses, many containing genes of similar nucleotide sequence and function. However, some tailed bacteriophage genomes can vary quite significantly in nucleotide sequence, even among the same genus. Due to their characteristic structure and possession of potentially homologous genes, it is believed these bacteriophages possess a common origin. [2]

Contents

There are 4 orders, 47 families, 98 subfamilies, 1197 genera, 3601 species in the class. This makes Caudoviricetes the most populous class among viruses, accounting for approximately 30% of all recognized virus species and nearly half of all virus genera. [3]

Infection

Upon encountering a host bacterium, the tail section of the virion binds to receptors on the cell surface and delivers the DNA into the cell by use of an injectisome-like mechanism (an injectisome is a nanomachine that evolved for the delivery of proteins by type III secretion). The tail section of the virus punches a hole through the bacterial cell wall and plasma membrane and the genome passes down the tail into the cell. Once inside the genes are expressed from transcripts made by the host machinery, using host ribosomes. Typically, the genome is replicated by use of concatemers, in which overlapping segments of DNA are made, and then put together to form the whole genome. [2]

Assembly and maturation

Viral capsid proteins come together to form a precursor prohead, into which the genome enters. Once this has occurred, the prohead undergoes maturation by cleavage of capsid subunits to form an icosahedral phage head with 5-fold symmetry. After the head maturation, the tail is joined in one of two ways: Either the tail is constructed separately, and joined with the connector, or the tail is constructed directly onto the phage head. The tails consist of helix based proteins with 6-fold symmetry. After maturation of virus particles, the cell is lysed by lysins, holins, or a combination of the two. [2]

Basis for Taxonomy

For most of virological history, Caudoviricetes which was known as the order Caudovirales, had lower taxa defined via morphology and contractile ability of their "tails". The Myoviridae had long tails that were contractile; the Podoviridae had short noncontractile tails; and the Siphoviridae had long noncontractile tails. [4] Siphoviridae constitute the majority of the known tailed viruses. [2] [5]

Bradley referred to what was known as the Myoviridae as type A, Siphoviridae as type B, and the Podoviridae as type C. He also divided his groups on the basis of head morphology: Within group A, A1 have small isometric heads; A2 have prolate heads; and A3 have elongated heads. Within groups B and C, numbers were similarly assigned: B1 and C1 have small isometric heads; B2 and C2 have prolate heads; and B3 and C3 have elongated heads.[ citation needed ]

Because the "families" Myoviridae, Podoviridae and Siphoviridae were abolished for being polyphyletic, there are now many free-floating families, subfamilies, and genera in the class without any preceding taxa before Caudoviricetes. There are currently 7 orders, 63 families, 109 subfamilies, 1360 genera, and 4079 species in the class. This article lists all official and proposed taxa of Caudoviricetes . (Note: Quotes means that the taxon is proposed and has not yet been ratified by the ICTV.)

Assigned Orders

Unassigned Taxa

There are a lot of Unassigned Taxa in Caudoviricetes as of ICTV 2022 [3]

Unassigned Genus in the Crassvirales Order

Unassigned Families

Unassigned genera in the Ackermannviridae Family

Unassigned genera in the Autographiviridae Family

Unassigned Genus in the Chaseviridae Family

Unassigned genera in the Demerecviridae Family

Unassigned genera in the Drexlerviridae Family

Unassigned genera in the Guelinviridae Family

Unassigned genera in the Herelleviridae Family

Unassigned Genus in the Mesyanzhinovviridae Family

Unassigned genera in the Pootjesviridae Family

Unassigned genera in the Rountreeviridae Family

Unassigned genera in the Salasmaviridae Family

Unassigned genera in the Schitoviridae Family

Unassigned Genera in the Straboviridae Family

Unassigned genera in the Vilmaviridae Family

Unassigned genera in the Zobellviridae Family

Unassigned Subfamilies

Unassigned Genera

Etymology

Crassvirales infects bacteria and is named after the computer program crAss, which was used to identify the first member of the Crassvirales order. [6] [7]

The rest (including the proposed orders) infect archaea . Kirjokansivirales , Thumleimavirales , and Nakonvirales are named after mythological objects or deities; Methanobavirales and Magrovirales are named after archaic synonyms of the archaea they infect.

Bacteriophage evolution

Bacteriophages occur in over 1100 bacterial or archaeal genera. [3] Over 6300 bacteriophages have been examined in the electron microscope since 1959. Of these, more than 96 percent have tails. Of the tailed phages, about 57 percent have long, noncontractile tails ("Siphoviridae"). Tailed phages appear to be monophyletic and are the oldest known virus group. [5] [8]

See also

Related Research Articles

<i>Escherichia virus T4</i> Species of bacteriophage

Escherichia virus T4 is a species of bacteriophages that infect Escherichia coli bacteria. It is a double-stranded DNA virus in the subfamily Tevenvirinae from the family Myoviridae. T4 is capable of undergoing only a lytic life cycle and not the lysogenic life cycle. The species was formerly named T-even bacteriophage, a name which also encompasses, among other strains, Enterobacteria phage T2, Enterobacteria phage T4 and Enterobacteria phage T6.

<i>Myoviridae</i> Family of viruses

Myoviridae was a family of bacteriophages in the order Caudovirales. The family Myoviridae and order Caudoviraleshave now been abolished, with the term myovirus now used to refer to the morphology of viruses in this former family. Bacteria and archaea serve as natural hosts. There were 625 species in this family, assigned to eight subfamilies and 217 genera.

<i>Podoviridae</i> Family of viruses

Podoviridae was a family of bacteriophage in the order Caudovirales often associated with T-7 like phages. The family and order Caudoviraleshave now been abolished, with the term podovirus now used to refer to the morphology of viruses in this former family. There were 130 species in this family, assigned to 3 subfamilies and 52 genera. This family was characterized by having very short, noncontractile tails. Many former phages in the former family Podoviriade are now classified in the Autographiviridae

A Bacillus phage is a member of a group of bacteriophages known to have bacteria in the genus Bacillus as host species. These bacteriophages have been found to belong to the families Myoviridae, Siphoviridae, Podoviridae, or Tectiviridae. The genus Bacillus includes the model organism, B. subtilis, and two widely known human pathogens, B. anthracis and B. cereus. Other strains of Bacillus bacteria that phage are known to infect include B. megaterium, B. mycoides, B. pseudomycoides, B. thuringiensis, and B. weihenstephanensis. More than 1,455 bacillus phage have been discovered from many different environments and areas around the world. Only 164 of these phages have been completely sequenced as of December 16, 2021.

<span class="mw-page-title-main">Cyanophage</span> Virus that infects cyanobacteria

Cyanophages are viruses that infect cyanobacteria, also known as Cyanophyta or blue-green algae. Cyanobacteria are a phylum of bacteria that obtain their energy through the process of photosynthesis. Although cyanobacteria metabolize photoautotrophically like eukaryotic plants, they have prokaryotic cell structure. Cyanophages can be found in both freshwater and marine environments. Marine and freshwater cyanophages have icosahedral heads, which contain double-stranded DNA, attached to a tail by connector proteins. The size of the head and tail vary among species of cyanophages. Cyanophages infect a wide range of cyanobacteria and are key regulators of the cyanobacterial populations in aquatic environments, and may aid in the prevention of cyanobacterial blooms in freshwater and marine ecosystems. These blooms can pose a danger to humans and other animals, particularly in eutrophic freshwater lakes. Infection by these viruses is highly prevalent in cells belonging to Synechococcus spp. in marine environments, where up to 5% of cells belonging to marine cyanobacterial cells have been reported to contain mature phage particles.

<i>Corticovirus</i> Genus of viruses

Corticovirus is a genus of viruses in the family Corticoviridae. Corticoviruses are bacteriophages; that is, their natural hosts are bacteria. The genus contains two species. The name is derived from Latin cortex, corticis. However, prophages closely related to PM2 are abundant in the genomes of aquatic bacteria, suggesting that the ecological importance of corticoviruses might be underestimated. Bacteriophage PM2 was first described in 1968 after isolation from seawater sampled from the coast of Chile.

<span class="mw-page-title-main">Corynebacteriophage</span> Virus of bacteria

A corynebacteriophage is a DNA-containing bacteriophage specific for bacteria of genus Corynebacterium as its host. Corynebacterium diphtheriae virus strain Corynebacterium diphtheriae phage introduces toxigenicity into strains of Corynebacterium diphtheriae as it encodes diphtheria toxin, it has subtypes beta c and beta vir. According to proposed taxonomic classification, corynephages β and ω are unclassified members of the genus Lambdavirus, family Siphoviridae.

<i>Autographiviridae</i> Subfamily of viruses

Autographiviridae is a family of viruses in the order Caudovirales. Bacteria serve as natural hosts. There are 373 species in this family, assigned to 9 subfamilies and 133 genera.

Picovirinae is a subfamily of viruses in the order Caudovirales, in the family Salasmaviridae. Bacteria serve as natural hosts. There are two genera and seven species in this subfamily.

Phikmvvirus is a genus of viruses that infect bacteria. There are currently 16 species in this genus including the type species Pseudomonas virus phiKMV. Bacteriophage phiKMV and its relatives are known to be highly virulent phages, producing large clear plaques on a susceptible host. The only reported exception is phage LKA1, which yields small plaques surrounded by a halo. While all other P. aeruginosa-specific phikmvviruses use the Type IV pili as primary receptor, LKA1 particles attach to the bacterial lipopolysaccharide layer.

Enquatrovirus is a genus of bacteriophages in the order Caudovirales, in the family Podoviridae. Bacteria serve as natural hosts. There is currently only one species in this genus: the type species Escherichia virus N4.

Uetakevirus is a genus of viruses in the order Caudovirales, in the family Podoviridae. Bacteria serve as natural hosts. There are three species in this genus. These phages are temperate and infect Salmonella and Escherichia coli.

<i>Okubovirus</i> Genus of viruses

Okubovirus is a genus of viruses in the order Caudovirales, in the family Herelleviridae, in the subfamily Spounavirinae. Bacteria serve as natural hosts. There are two species in this genus.

Mannheimia virus PHL101 is a virus of the family Myoviridae, genus Baylorvirus.

Peduovirus is a genus of viruses in the order Caudovirales, in the family Myoviridae, in the subfamily Peduovirinae. Bacteria serve as natural hosts, with transmission achieved through passive diffusion. There are 15 species in this genus.

Spbetavirus is a genus of viruses in the order Caudovirales, in the family Siphoviridae. Bacteria serve as natural hosts. There is only one species in this genus: Bacillus virus SPbeta.

Tequintavirus is a genus of viruses in the order Caudovirales, in the family Demerecviridae. Bacteria serve as the natural host, with transmission achieved through passive diffusion. There are currently 22 species in this genus, including the type species Escherichia virus T5.

Escherichia virus CC31, formerly known as Enterobacter virus CC31, is a dsDNA bacteriophage of the subfamily Tevenvirinae responsible for infecting the bacteria family of Enterobacteriaceae. It is one of two discovered viruses of the genus Karamvirus, diverging away from the previously discovered T4virus, as a clonal complex (CC). CC31 was first isolated from Escherichia coli B strain S/6/4 and is primarily associated with Escherichia, even though is named after Enterobacter.

Ackermannviridae is a family of viruses in the order Caudovirales. Gammaproteobacteria in the phylum Pseudomonadota serve as natural hosts. There are 2 subfamilies, 10 genera, and 63 species in the family.

<i>Duplodnaviria</i> Realm of viruses

Duplodnaviria is a realm of viruses that includes all double-stranded DNA viruses that encode the HK97 fold major capsid protein. The HK97 fold major capsid protein is the primary component of the viral capsid, which stores the viral deoxyribonucleic acid (DNA). Viruses in the realm also share a number of other characteristics, such as an icosahedral capsid, an opening in the viral capsid called a portal, a protease enzyme that empties the inside of the capsid prior to DNA packaging, and a terminase enzyme that packages viral DNA into the capsid.

References

  1. ↑ Ackermann HW (1998). Tailed bacteriophages: the order caudovirales. Vol. 51. pp. 135–201. doi:10.1016/S0065-3527(08)60785-X. ISBN   9780120398515. PMC   7173057 . PMID   9891587.{{cite book}}: |journal= ignored (help)
  2. 1 2 3 4 5 6 "Double-Stranded DNA Bacteriophages". Boundless. 2017-11-11. Archived from the original on 2013-06-28.
  3. 1 2 3 "Virus Taxonomy: 2022 Release". International Committee on Taxonomy of Viruses (ICTV). March 2023. Retrieved 5 November 2023.
  4. ↑ Maniloff J, Ackermann HW (1998). "Taxonomy of bacterial viruses: establishment of tailed virus genera and the order Caudovirales". Archives of Virology. 143 (10): 2051–63. doi: 10.1007/s007050050442 . PMID   9856093. S2CID   34921877.
  5. 1 2 Ackermann HW (May 2003). "Bacteriophage observations and evolution". Research in Microbiology. 154 (4): 245–51. doi: 10.1016/S0923-2508(03)00067-6 . PMID   12798228.
  6. ↑ Turner, Dann; et al. (2023). "Abolishment of morphology-based taxa and change to binomial species names: 2022 taxonomy update of the ICTV bacterial viruses subcommittee". Archives of Virology. 168 (2): 74. doi:10.1007/s00705-022-05694-2. PMC   9868039 . PMID   36683075.
  7. ↑ "ICTV proposal Download".
  8. ↑ Ackermann HW, Prangishvili D (October 2012). "Prokaryote viruses studied by electron microscopy". Archives of Virology. 157 (10): 1843–9. doi:10.1007/s00705-012-1383-y. PMID   22752841. S2CID   16699662.

Further reading

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