Potexvirus

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Potexvirus
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Color break symptoms caused by narcissus mosaic virus (NMV) in daffodils (A, B) and normal flower (C)
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Kitrinoviricota
Class: Alsuviricetes
Order: Tymovirales
Family: Alphaflexiviridae
Genus:Potexvirus

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. [1] [2] The genus name comes from POTato virus X).

Contents

Taxonomy

Potexvirus contains one subgenus that has three species and 45 additional species unassigned to a subgenus. The following 48 species are assigned to the genus: [2]

The following species are unassigned to a subgenus:

Virology

The virion length may vary considerably (between 470 and 1000 nanometers or more) and is 12-13 nm in diameter. The pitch of the helix is of the basic helix 3.3-3.7 nm (8-9 copies of the coat protein per turn). It is non-enveloped, flexuous and filamentous. The coat itself is composed of 1000-1500 copies of the coat protein. [1]

The genome is linear, 5.9-7 kilobases in length with a capped 5' end and a polyadenylated 3' end. The genome encodes 5 proteins. From left to right these proteins are: the viral replication protein that consists of a capping enzyme domain, a helicase-like domain, the RNA dependent RNA polymerase, three proteins - the triple gene block (TGB) 1, 2 and 3 - and the coat protein. [1]

GenusStructureSymmetryCapsidGenomic arrangementGenomic segmentation
PotexvirusFilamentousNon-envelopedLinearMonopartite

The RNA is translated giving rise to the viral RNA polymerase. This in turn produces a negative stranded template from which a series of subgenomic RNAs are generated. These subgenomic RNAs are then translated into the viral proteins.

The 5' end is about 80 nucleotides in length and typically begins with the sequence GAAAA. [3]

In addition to its RNA polymerase activity, the viral RNA polymerase (molecular weight ~150 kiloDaltons) also has methyltransferase and RNA helicase activities.

The TGB proteins are conserved among the Allexivirus, Carlavirus, Foveavirus, Furovirus, Hordeivirus, Pecluvirus, Pomovirus and Potexvirus genera. Their functions are a matter of active research.

TGB 1 (molecular weight 23 kDa) is a multifunctional protein. It has RNA helicase activity and seems to be involved in cell to cell movement.

The TGB 2 (molecular weight 11 kDa) and TGB 3 (molecular weight 10 kDa) proteins associate with the endoplasmic reticulum.

The coat protein has a molecular weight of ~25kDa.

The 3' untranslated region is ~100 nucleotides in length.

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. The virus exits the host cell by tripartite non-tubule guided viral movement. The virus is transmitted via a vector (insects). Transmission routes are vector and mechanical. [1]

GenusHost detailsTissue tropismEntry detailsRelease detailsReplication siteAssembly siteTransmission
PotexvirusPlantsNoneViral movement; mechanical inoculationViral movementCytoplasmCytoplasmInsects

Hosts

Known hosts are various flowering plants.

Distribution

These viruses appear to occur worldwide.

Related Research Articles

<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>Tobamovirus</i> Genus of viruses

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

<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.

<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.

Dianthovirus is a genus of viruses, in the family Tombusviridae. Dianthoviruses are plant viruses. There are three species in this genus. The virus probably has a worldwide distribution, and can be transmitted via nematodes, by mechanical inoculation, by grafting of plants and by contact between infected hosts with previously uninfected host.

<i>Alfalfa mosaic virus</i> Species of virus

Alfalfa mosaic virus (AMV), also known as Lucerne mosaic virus or Potato calico virus, is a worldwide distributed phytopathogen that can lead to necrosis and yellow mosaics on a large variety of plant species, including commercially important crops. It is the only Alfamovirus of the family Bromoviridae. In 1931 Weimer J.L. was the first to report AMV in alfalfa. Transmission of the virus occurs mainly by some aphids, by seeds or by pollen to the seed.

<i>Cymbidium mosaic virus</i> Species of virus

Cymbidium mosaic virus (CymMV) is a plant pathogenic virus of the family Alphaflexiviridae.

<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.

Idaeovirus is a genus of positive-sense ssRNA viruses that contains two species: Raspberry bushy dwarf virus (RBDV) and Privet idaeovirus. RBDV has two host-dependent clades: one for raspberries; the other for grapevines. Infections are a significant agricultural burden, resulting in decreased yield and quality of crops. RBDV has a synergistic relation with Raspberry leaf mottle virus, with co-infection greatly amplifying the concentration of virions in infected plants. The virus is transmitted via pollination with RBDV-infected pollen grains that first infect the stigma before causing systemic infection.

<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>Alphaflexiviridae</i> Family of viruses in the order Tymovirales affecting plants and fungi

Alphaflexiviridae is a family of viruses in the order Tymovirales. Plants and fungi serve as natural hosts. There are 65 species in this family, assigned to six genera. Diseases associated with this family include: mosaic and ringspot symptoms.

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.

Cilevirus is a genus of viruses in the family Kitaviridae. Plants serve as natural hosts. There are two species: Citrus leprosis virus C and Citrus leprosis virus C2.

Allexivirus is a genus of viruses in the order Tymovirales, in the family Alphaflexiviridae. Shallot, onion, and garlic serve as natural hosts. There are 13 species in this genus, seven of which are assigned to a subgenus. Diseases associated with this genus include: mosaic and ringspot symptoms.

<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.

Mandarivirus is a subgenus of viruses in the order Tymovirales, family Alphaflexiviridae, genus Potexvirus. There are three species in this subgenus. Diseases associated with this subgenus commonly include yellow ringspot and rapid decline of the tree.

Lily virus X (LVX) is a pathogenic ssRNA(+) plant virus of the family Alphaflexiviridae and the order Tymovirales.

Cassava brown streak virus is a species of positive-strand RNA viruses in the genus Ipomovirus and family Potyviridae which infects plants. Member viruses are unique in their induction of pinwheel, or scroll-shaped inclusion bodies in the cytoplasm of infected cells. Cylindrical inclusion bodies include aggregations of virus-encoded helicase proteins. These inclusion bodies are thought to be sites of viral replication and assembly, making then an important factor in the viral lifecycle. Viruses from both the species Cassava brown streak virus and Ugandan cassava brown streak virus (UCBSV), lead to the development of Cassava Brown Streak Disease (CBSD) within cassava plants.

References

  1. 1 2 3 4 "Viral Zone". ExPASy. Retrieved 15 June 2015.
  2. 1 2 "Virus Taxonomy: 2020 Release". International Committee on Taxonomy of Viruses (ICTV). March 2021. Retrieved 15 May 2021.
  3. ↑ Côté, F.; Paré, C.; Majeau, N.; Bolduc, M. N.; Leblanc, É.; Bergeron, M. G.; Bernardy, M. G.; Leclerc, D. (2008). "Nucleotide sequence and phylogenetic analysis of a new potexvirus: Malva Mosaic Virus". Infection, Genetics and Evolution. 8 (1): 83–93. doi:10.1016/j.meegid.2007.10.006. PMID   18054524.
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