Tobamovirus

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Tobamovirus
electron micrograph
of virions
Virus classification Edit this classification
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Kitrinoviricota
Class: Alsuviricetes
Order: Martellivirales
Family: Virgaviridae
Genus: Tobamovirus

Tobamovirus is a genus of

squash, serve as natural hosts. Diseases associated with this genus include: necrotic lesions on leaves.[3][4] The name Tobamovirus comes from the host and symptoms of the first virus discovered (Tobacco mosaic virus).[5]

There are four informal subgroups within this genus: these are the tobamoviruses that infect the brassicas, cucurbits, malvaceous, and solanaceous plants. The main differences between these groups are genome sequences, and respective range of host plants.[citation needed] There are 37 species in this genus.[6]

Structure

Tobamoviruses are non-enveloped, with helical rod[2] geometries, and helical symmetry. The diameter is around 18 nm, with a length of 300–310 nm. Genomes are linear and non-segmented, around 6.3–6.5kb in length.[3][4]

Genome

The RNA genome encodes at least four

plasmodesmata, they are probably involved in host specificity as they are believed to interact with some host cell factors.[citation needed
]

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 suppression of termination. The virus exits the host cell by monopartite non-tubule guided viral movement. Plants serve as the natural host.[2] Transmission routes are mechanical.[3][4]

Enzymes

Tobamovirus RNA-dependent RNA polymerases are homologous with bromoviruses, ilarviruses, tobraviruses, and the carnation mottle virus.[2]

Routes of infection

The infection is localized to begin with but if the virus remains unchallenged it will spread via the vascular system into a systemic infection. The exact mechanism the virus uses to move throughout the plant is unknown but the interaction of

cell wall metabolism and plant development, with the movement protein has been implicated.[8]

Evolution

There are at least 3 distinct clades of tobamoviruses, which to some extent follow their host ranges: that is, there is one infecting

solanaceous species; a second infecting cucurbits and legumes and a third infecting the crucifers.[9]

Classification

Species

Phylogenetic tree of Tobamovirus

The genus contains the following species:[6]

Proposed members

Proposed, but currently unrecognised members of the genus include:[11]

  • Chara corallina virus (CCV)
  • Nicotiana velutina mosaic virus (NVMV)

References

  1. ^ "Virus Taxonomy: 2018b Release". International Committee on Taxonomy of Viruses (ICTV). March 2019. Archived from the original on 20 March 2020. Retrieved 18 March 2019.
  2. ^
    PMID 3060004
    .
  3. ^ a b c d e "ICTV Online Report Virgaviridae". Archived from the original on 9 July 2023. Retrieved 21 September 2017.
  4. ^ a b c "Viral Zone". ExPASy. Archived from the original on 27 June 2015. Retrieved 15 June 2015.
  5. ^ "MINUTES OF THE THIRD MEETING OF ICTV held in MADRID, 12 and 16 September 1975" (PDF). Archived (PDF) from the original on 9 April 2023. Retrieved 9 July 2023.
  6. ^ a b "Virus Taxonomy: 2020 Release". International Committee on Taxonomy of Viruses (ICTV). March 2021. Archived from the original on 20 March 2020. Retrieved 14 May 2021.
  7. PMID 10072391
    .
  8. PMID 12887589
    .
  9. PMID 8952077
    .
  10. S2CID 40760030
    .
  11. ^ a b "Descriptions of Plant Viruses: Tobamovirus Group". The Association of Applied Biologists (AAB). Archived from the original on 17 November 2007. Retrieved 7 April 2008.

Further reading

External links

Wikimedia Commons has media related to Tobamovirus.
Wikispecies has information related to Tobamovirus.