Virgaviridae

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Virgaviridae
TobaccoMosaicVirus.jpg

TEM uptake of virions of the tobacco mosaic virus (TMV),
negatively stained with heavy metal.

Systematics
Classification : Viruses
Area : Riboviria
Empire : Orthornavirae
Phylum : Kitrinoviricota
Class : Alsuviricetes
Order : Martellivirales
Family : Virgaviridae
Taxonomic characteristics
Genome : (+) ss DNA segmented linearly
Baltimore : Group 4
Symmetry : rod-shaped helical
Cover : no
Scientific name
Virgaviridae
Left
NCBI  Taxonomy: 675071
ViralZone ( ExPASy , SIB): 734

The Virgaviridae are a family of single-stranded RNA viruses with positive polarity . Their natural hosts are plants. There are currently at least 59 species in this family, divided into 7 genera. The name of the family is derived from the Latin virga 'stick, stick' , also 'rod' (since all viruses in this family are rod-shaped or rod-shaped).

construction

The virus particles ( virions ) of the Virgaviridae are not enveloped, their geometry is rigidly rod-shaped and they have a helical symmetry. The diameter is 20-25  nm . The virions have a central “channel”.

The genome consists of a linear, single-stranded positive sense RNA with a 3'- tRNA -like structure and no poly-A tail . The genome can be present in one, two or three segments (mono-, bi- or tripartite) depending on the genus. The envelope proteins range in size from 19 to 24 kilodaltons .

Propagation cycle

Replication of the virus particles is cytoplasmic (i.e. it takes place in the cytoplasm ) and follows the replication model of positive strand RNA viruses. The transcription method is also the usual one for positive-strand RNA viruses. The translation used by leaky scanning and suppression of termination.

The natural hosts are plants.

Systematics

Internal system

According to the International Committee on Taxonomy of Viruses (ICTV) as of March 2019, the internal systematics of the Virgaviridae are as follows:

Family Virgaviridae

External system

In 2015, Koonin et al taxonomically assigned the Virgaviridae (due to their relationship) to the supergroup 'Alphavirus-like superfamily' they postulated. The sister group is thereafter the family Closteroviridae . According to the authors, the family tree of this supergroup is as follows:


 " Alphavirus- like superfamily "  


 " Tetraviridae " ( split from ICTV 2011) 

Alphatetraviridae , (with Helicoverpa armigera stunt virus )


   

Carmotetraviridae (with Providence virus )


   

Permutotetraviridae (with Thosea asigna virus )


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? Birnaviridae (dsRNA)



   





Virgaviridae


   

Closteroviridae



   

Bromoviridae



   

Tymovirales ( order )



   

Endornaviridae (dsRNA, with Oryza sativa alphaendornavirus )



   

Hepeviridae


   

Togaviridae (with alphavirus )


   

? Matonaviridae (with rubella virus - by ICTV in 2019 from the Togaviridae outsourced )


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? Nodaviridae (with Boolarra virus )



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The members of this proposed supergroup belong to different groups of the Baltimore classification , usually they are single-stranded RNA viruses of positive polarity ((+) ssRNA, Baltimore group 4), but there are also double-stranded representatives (marked with dsRNA, Find Baltimore Group 3).

Although its members are rod-shaped and infect plants, the genus Benyvirus does not belong to this family, but to the Benyviridae ; the proteins of the two groups are apparently only largely related. According to the proposal, another related genus is Charavirus with the species Charavirus canadensis (CV-Can) and Charavirus australis (CV-Aus), these viruses attack charophytes .

Individual evidence

  1. ↑ ICTV Master Species List 2018b.v2 . MSL # 34, March 2019
  2. ↑ a b c d ICTV: ICTV Master Species List 2019.v1 , New MSL including all taxa updates since the 2018b release, March 2020 (MSL # 35)
  3. ↑ Michael J. Adams, Scott Adkins, Claude Bragard, David Gilmer, Dawei Li, Stuart A. MacFarlane, Sek-Man Wong, Ulrich Melcher, Claudio Ratti, Ki Hyun Ryu: ICTV Virus Taxonomy Profile: Virgaviridae . In: Journal of General Virology . 98, No. 8, August 1, 2017, pp. 1999–2000. doi : 10.1099 / jgv.0.000884 . PMID 28786782 . PMC 5656781 (free full text).
  4. ↑ a b c d e f g ICTV Report Virgaviridae .
  5. ↑ a b c d e f g Viral Zone . ExPASy. Retrieved September 2, 2019.
  6. ↑ Adams MJ, Antoniw JF, crosses J: Virgaviridae : a new family of rod-shaped plant viruses. Arch Virol 154 (12), 2009, pp. 1967-1972
  7. ↑ ICTV: Virus Taxonomy: 2015 Release . Retrieved June 4, 2016.
  8. ↑ virga | Latin → German , on: Pons.de
  9. ↑ ICTV : ICTV MSL # 34v 2018b.v2 , March 2019
  10. ↑ MJ Adams, P. Jones, AG Swaby: Purification and some properties of oat golden stripe virus , in: Annals of Applied Biology, April 1988, doi: 10.1111 / j.1744-7348.1988.tb02064.x
  11. ↑ Min BE, Chung BN, Kim MJ, Ha JH, Lee BY, Ryu KH: Cactus mild mottle virus is a new cactus-infecting tobamovirus . In: Archives of Virology . 151, No. 1, January 2006, pp. 13-21. doi : 10.1007 / s00705-005-0617-7 . PMID 16132178 .
  12. ↑ Since this group (referred to by the authors as English superfamily ) contains an order with the Tymovirales , their rank must be higher than this and should not be understood as a superfamily . Ranks higher than order were not given by the ICTV at the time of the work.
  13. ^ Eugene V. Koonin, Valerian V. Dolja, Mart Krupovic: Origins and evolution of viruses of eukaryotes: The ultimate modularity , in: Virology from May 2015; 479-480. 2-25, Epub March 12, 2015, PMC 5898234 (free full text), PMID 25771806
  14. ↑ SIB: Alphatetraviridae , on: ViralZone
  15. ↑ SIB: Carmotetraviridae , on: ViralZone
  16. ↑ SIB: Permutotetraviridae , on: ViralZone
  17. ↑ SIB: Endornaviridae , on: ViralZone
  18. ↑ SIB: Nodaviridae , on: ViralZone
  19. ↑ ICTV Report Benyviridae .
  20. ^ Marli Vlok, Adrian J. Gibbs. Curtis A. Suttle: Metagenomes of a Freshwater Charavirus from British Columbia Provide a Window into Ancient Lineages of Viruses , in: Viruses, Volume 11, No. 3, 299, March 25, 2019, doi: 10.3390 / v11030299 , PMC 6466400 (freer Full text), PMID 30934644

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