Virgaviridae

Virgaviridae
Tobacco mosaic virus (TMV) diagram and electron micrograph of virions
Virus classification
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Kitrinoviricota
Class: Alsuviricetes
Order: Martellivirales
Family: Virgaviridae
Genera

Virgaviridae is a family of positive-strand RNA viruses. Plants serve as natural hosts.[1][2][3][4] The name of the family is derived from the Latin word virga (rod), as all viruses in this family are rod-shaped. There are currently 59 species in this family, divided among seven genera.[2][3][5]

Structure

Viruses in Virgaviridae are non-enveloped, with rigid helical rod geometries, and helical symmetry. The diameter is around 20-25 nm,[2][3] and virions have a central "canal." Genomes are linear, single-stranded, positive sense RNA[2][3] with a 3'-tRNA like structure and no polyA tail. They may be in one, two, or three segments, depending on the genus. Coat proteins are about 19–24 kiloDaltons.

GenusStructureSymmetryCapsidGenomic arrangementGenomic segmentation
TobamovirusRod-shapedHelicalNon-envelopedLinearNon-Segmented
FurovirusRod-shapedHelicalNon-envelopedLinearSegmented
PecluvirusRod-shapedHelicalNon-envelopedLinearSegmented
HordeivirusRod-shapedHelicalNon-envelopedLinearSegmented
TobravirusRod-shapedHelicalNon-envelopedLinearSegmented
PomovirusRod-shapedHelicalNon-envelopedLinearSegmented

Life cycle

Viral replication is cytoplasmic. Entry into the host cell is achieved by penetration into the host cell. Replication follows the positive stranded RNA virus replication model. Positive stranded RNA virus transcription is the method of transcription. Translation takes place by leaky scanning, and suppression of termination. The virus exits the host cell by tripartite non-tubule guided viral movement, and monopartite non-tubule guided viral movement. Plants serve as the natural host.[2][3]

GenusHost detailsTissue tropismEntry detailsRelease detailsReplication siteAssembly siteTransmission
TobamovirusPlantsNoneUnknownViral movementCytoplasmCytoplasmMechanical
FurovirusPlantsNoneUnknownViral movementCytoplasmCytoplasmMechanical inoculation: fungus
PecluvirusPlantsNoneUnknownViral movementCytoplasmCytoplasmMechanical inoculation: fungus. Mechanical contact; seed
HordeivirusPlantsNoneUnknownViral movementCytoplasmCytoplasmMechanical: contact; seed
TobravirusPlantsNoneUnknownViral movementCytoplasmCytoplasmMechanical inoculation: nematodes
PomovirusPlantsNoneUnknownViral movementCytoplasmCytoplasmMechanical inoculation: fungus

Taxonomy

Viruses include in the family Virgaviridae are characterized by unique alpha-like replication proteins.

The following genera are recognized:

Notes

The genus Benyvirus, although its members are rod shaped and infect plants, is not included in this family as its proteins appear to be only very distantly related, but is instead included in the family Benyviridae.[6] Another related genus is Charavirus. Viruses of this genus infect charophyte algae.

References

  1. ↑ Adams, Michael J.; Adkins, Scott; Bragard, Claude; Gilmer, David; Li, Dawei; MacFarlane, Stuart A.; Wong, Sek-Man; Melcher, Ulrich; Ratti, Claudio; Ryu, Ki Hyun (1 August 2017). "ICTV Virus Taxonomy Profile: Virgaviridae". Journal of General Virology. 98 (8): 1999–2000. doi:10.1099/jgv.0.000884. PMC 5656781. PMID 28786782.
  2. 1 2 3 4 5 "ICTV Report Virgaviridae".
  3. 1 2 3 4 5 "Viral Zone". ExPASy. Retrieved 15 June 2015.
  4. ↑ Adams MJ, Antoniw JF, Kreuze J (2009) Virgaviridae: a new family of rod-shaped plant viruses. Arch Virol 154(12):1967–1972
  5. ↑ ICTV. "Virus Taxonomy: 2015 Release". Retrieved 4 June 2016.
  6. ↑ "ICTV Report Benyviridae".
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