Tobamovirus

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Tobamovirus
OPSR.Virga.Fig16.png
Tobacco mosaic virus (TMV) diagram and electron micrograph of virions
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Kitrinoviricota
Class: Alsuviricetes
Order: Martellivirales
Family: Virgaviridae
Genus:Tobamovirus

Tobamovirus is a genus of positive-strand RNA viruses [1] in the family Virgaviridae. [2] Many plants, [1] including tobacco, potato, tomato, and squash, serve as natural hosts. Diseases associated with this genus include: necrotic lesions on leaves. [2] [3] The name Tobamovirus comes from the host and symptoms of the first virus discovered (Tobacco mosaic virus). [4]

Contents

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. [5]

Structure

Tobamoviruses are non-enveloped, with helical rod [1] 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. [2] [3]

Genome

The RNA genome encodes at least four polypeptides: [2] these are the non-structural protein and the read-through product which are involved in virus replication (RNA-dependent RNA polymerase, RdRp); the movement protein (MP) which is necessary for the virus to move between cells and the coat protein (CP). The read-through portion of the RdRp may be expressed as a separate protein in TMV. [6] The virus is able to replicate without the movement or coat proteins, but the other two are essential. The non-structural protein has domains suggesting it is involved in RNA capping and the read-through product has a motif for an RNA polymerase. The movement proteins are made very early in the infection cycle and localized to the 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. [1] Transmission routes are mechanical. [2] [3]

Enzymes

Tobamovirus RNA-dependent RNA polymerases are homologous with bromoviruses, ilarviruses, tobraviruses, and the carnation mottle virus. [1]

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 pectin methylesterase, a cellular enzyme important for cell wall metabolism and plant development, with the movement protein has been implicated. [7]

Evolution

These viruses are thought to have codiverged with their hosts from a common ancestor. [8] 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 12985 2016 676 Fig2 HTML.webp
Phylogenetic tree of Tobamovirus

The genus contains the following species: [5]

Proposed members

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

Related Research Articles

<i>Tobacco mosaic virus</i> Virus affecting plants of the Solanaceae family

Tobacco mosaic virus (TMV) is a positive-sense single-stranded RNA virus species in the genus Tobamovirus that infects a wide range of plants, especially tobacco and other members of the family Solanaceae. The infection causes characteristic patterns, such as "mosaic"-like mottling and discoloration on the leaves. TMV was the first virus to be discovered. Although it was known from the late 19th century that a non-bacterial infectious disease was damaging tobacco crops, it was not until 1930 that the infectious agent was determined to be a virus. It is the first pathogen identified as a virus. The virus was crystallised by Wendell Meredith Stanley. It has a similar size to the largest synthetic molecule, known as PG5.

<span class="mw-page-title-main">Satellite (biology)</span> Subviral agent which depends on a helper virus for its replication

A satellite is a subviral agent that depends on the coinfection of a host cell with a helper virus for its replication. Satellites can be divided into two major classes: satellite viruses and satellite nucleic acids. Satellite viruses, which are most commonly associated with plants, are also found in mammals, arthropods, and bacteria. They encode structural proteins to enclose their genetic material, which are therefore distinct from the structural proteins of their helper viruses. Satellite nucleic acids, in contrast, do not encode their own structural proteins, but instead are encapsulated by proteins encoded by their helper viruses. The genomes of satellites range upward from 359 nucleotides in length for satellite tobacco ringspot virus RNA (STobRV).

<i>Geminiviridae</i> Family of viruses

Geminiviridae is a family of plant viruses that encode their genetic information on a circular genome of single-stranded (ss) DNA. There are 520 species in this family, assigned to 14 genera. Diseases associated with this family include: bright yellow mosaic, yellow mosaic, yellow mottle, leaf curling, stunting, streaks, reduced yields. They have single-stranded circular DNA genomes encoding genes that diverge in both directions from a virion strand origin of replication. According to the Baltimore classification they are considered class II viruses. It is the largest known family of single stranded DNA viruses.

<i>Tombusviridae</i> Family of viruses

Tombusviridae is a family of single-stranded positive sense RNA plant viruses. There are three subfamilies, 17 genera, and 95 species in this family. The name is derived from Tomato bushy stunt virus (TBSV).

<i>Tomato bushy stunt virus</i> Species of virus

Tomato bushy stunt virus (TBSV) is a virus of the tombusvirus family. It was first reported in tomatoes in 1935 and primarily affects vegetable crops, though it is not generally considered an economically significant plant pathogen. Depending upon the host, TBSV causes stunting of growth, leaf mottling, and deformed or absent fruit. The virus is likely to be soil-borne in the natural setting, but can also be transmitted mechanically, for example through contaminated cutting tools. TBSV has been used as a model system in virology research on the life cycle of plant viruses, particularly in experimental infections of the model host plant Nicotiana benthamiana.

<i>Potyvirus</i> Genus of positive-strand RNA viruses in the family Potyviridae

Potyvirus is a genus of positive-strand RNA viruses in the family Potyviridae. Plants serve as natural hosts. Like begomoviruses, members of this genus may cause significant losses in agricultural, pastoral, horticultural, and ornamental crops. More than 200 species of aphids spread potyviruses, and most are from the subfamily Aphidinae. The genus contains 190 species and potyviruses account for about thirty percent of all currently known plant viruses.

Tombusvirus is a genus of viruses, in the family Tombusviridae. Plants serve as natural hosts. There are 17 species in this genus. Symptoms associated with this genus include mosaic. The name of the genus comes from Tomato bushy stunt virus.

<i>Cowpea chlorotic mottle virus</i> Species of virus

Cowpea chlorotic mottle virus, known by the abbreviation CCMV, is a virus that specifically infects the cowpea plant, or black-eyed pea. The leaves of infected plants develop yellow spots, hence the name "chlorotic". Similar to its "brother" virus, Cowpea mosaic virus (CPMV), CCMV is produced in high yield in plants. In the natural host, viral particles can be produced at 1–2 mg per gram of infected leaf tissue. Belonging to the bromovirus genus, cowpea chlorotic mottle virus (CCMV) is a small spherical plant virus. Other members of this genus include the brome mosaic virus (BMV) and the broad bean mottle virus (BBMV).

<i>Nepovirus</i> Genus of viruses

Nepovirus is a genus of viruses in the order Picornavirales, in the family Secoviridae, in the subfamily Comovirinae. Plants serve as natural hosts. There are 40 species in this genus. Nepoviruses, unlike the other two genera in the subfamily Comovirinae, are transmitted by nematodes.

<i>Ilarvirus</i> Genus of viruses

Ilarvirus is a genus of positive-strand RNA viruses in the family Bromoviridae. Plants serve as natural hosts. There are 22 species in this genus.

<i>Sobemovirus</i> Genus of viruses

Sobemovirus is a genus of non-enveloped, positive-strand RNA viruses which infect plants.. Plants serve as natural hosts. There are 21 species in this genus. Diseases associated with this genus include: mosaics and mottles.

<i>Potexvirus</i> Genus of viruses

Potexvirus is a genus of pathogenic viruses in the order Tymovirales, in the family Alphaflexiviridae. Plants serve as natural hosts. There are 48 species in this genus, three of which are assigned to a subgenus. Diseases associated with this genus include: mosaic and ringspot symptoms. The genus name comes from POTato virus X).

<i>Carlavirus</i> Genus of viruses

Carlavirus, formerly known as the "Carnation latent virus group", is a genus of viruses in the order Tymovirales, in the family Betaflexiviridae. Plants serve as natural hosts. There are 53 species in this genus. Diseases associated with this genus include: mosaic and ringspot symptoms.

<i>Cucumovirus</i> Genus of viruses

Cucumovirus is a genus of viruses, in the family Bromoviridae. Plants serve as natural hosts. There are four species in this genus.

<i>Virgaviridae</i> Family of viruses

Virgaviridae is a family of positive-strand RNA viruses. Plants serve as natural hosts. 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.

Ipomovirus is a genus of positive-strand RNA viruses in the family Potyviridae. Member viruses infect plants and are transmitted by whiteflies. The name of the genus is derived from Ipomoea – the generic name of sweet potato. There are seven species in this genus.

<i>Bromovirus</i> Genus of viruses

Bromovirus is a genus of viruses, in the family Bromoviridae. Plants serve as natural hosts. There are six species in this genus.

<i>Comovirus</i> Genus of viruses

Comovirus is a genus of viruses in the order Picornavirales, in the family Secoviridae, in the subfamily Comovirinae. Plants serve as natural hosts. There are 15 species in this genus.

<i>Tymovirus</i> Genus of viruses

Tymovirus is a genus of viruses in the order Tymovirales, in the family Tymoviridae. Plants serve as natural hosts. There are 28 species in this genus.

<i>Riboviria</i> Realm of viruses

Riboviria is a realm of viruses that includes all viruses that use a homologous RNA-dependent polymerase for replication. It includes RNA viruses that encode an RNA-dependent RNA polymerase, as well as reverse-transcribing viruses that encode an RNA-dependent DNA polymerase. RNA-dependent RNA polymerase (RdRp), also called RNA replicase, produces RNA from RNA. RNA-dependent DNA polymerase (RdDp), also called reverse transcriptase (RT), produces DNA from RNA. These enzymes are essential for replicating the viral genome and transcribing viral genes into messenger RNA (mRNA) for translation of viral proteins.

References

  1. 1 2 3 4 5 Strauss, J H; Strauss, E G (1988). "Evolution of RNA Viruses". Annual Review of Microbiology . Annual Reviews. 42 (1): 657–683. doi:10.1146/annurev.mi.42.100188.003301. ISSN   0066-4227. PMID   3060004.
  2. 1 2 3 4 5 "ICTV Online Report Virgaviridae". Archived from the original on 9 July 2023. Retrieved 21 September 2017.
  3. 1 2 3 "Viral Zone". ExPASy. Archived from the original on 27 June 2015. Retrieved 15 June 2015.
  4. "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.
  5. 1 2 "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.
  6. Creager, Angela N.H.; Scholthof, Karen-Beth G.; Citovsky, Vitaly; Scholthof, Herman B. (March 1999). "Tobacco Mosaic Virus: Pioneering Research for a Century". The Plant Cell. 11 (3): 301–8. doi:10.1105/tpc.11.3.301. PMC   1464663 . PMID   10072391.
  7. Chen, M. H.; Citovsky, V. (August 2003). "Systemic movement of a tobamovirus requires host cell pectin methylesterase". The Plant Journal. 35 (3): 386–92. doi: 10.1046/j.1365-313X.2003.01818.x . PMID   12887589.
  8. Stobbe, A. H.; Melcher, U.; Palmer, M. W.; Roossinck, M. J.; Shen, G. (2012). "Co-divergence and host-switching in the evolution of tobamoviruses". Journal of General Virology. 93 (2): 408–18. doi: 10.1099/vir.0.034280-0 . PMID   22049092.
  9. Lartey, R. T.; Voss, T. C.; Melcher, U. (1996). "Tobamovirus evolution: Gene overlaps, recombination, and taxonomic implications" (PDF). Molecular Biology and Evolution. 13 (10): 1327–1338. doi: 10.1093/oxfordjournals.molbev.a025579 . PMID   8952077.
  10. Min, B. E.; Chung, B. N.; Kim, M. J.; Ha, J. H.; Lee, B. Y.; Ryu, K. H. (January 2006). "Cactus mild mottle virus is a new cactus-infecting tobamovirus". Archives of Virology. 151 (1): 13–21. doi:10.1007/s00705-005-0617-7. PMID   16132178. S2CID   40760030.
  11. 1 2 "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