Potyviridae

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Patatavirales
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Potyviridae
Genome of
plum pox virus of genus Potyvirus with transmission electron micrograph and model of virions
Virus classification Edit this classification
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Pisuviricota
Class: Stelpaviricetes
Order: Patatavirales
Family: Potyviridae
Genera

see text

Potyviridae is a family of positive-strand RNA viruses that encompasses more than 30% of known plant viruses,[1][2] many of which are of great agricultural significance. The family has 12 genera and 235 species, three of which are unassigned to a genus.[3][4][5][6]

Structure

Genomic map of a typical member of the genus Potyvirus.

Potyvirid virions are nonenveloped, flexuous filamentous, rod-shaped particles. The diameter is around 11–20 nm, with a length of 650–950 nm.[4][5]

Genome

Genomes are linear and usually nonsegmented, around 8–12kb in length,[4][5] consisting of positive-sense RNA, which is surrounded by a protein coat made up of a single viral encoded protein called a capsid. All induce the formation of virus inclusion bodies called cylindrical inclusions (‘pinwheels’) in their hosts. These consist of a single protein (about 70 kDa) made in their hosts from a single viral genome product.[citation needed]

Member viruses encode large polypeptides that are cleaved into mature proteins. In 5'–3' order these proteins are

  • P1 (a serine protease): 83 kDa
  • HC (a protease): 51 kDa
  • P3: 34 kDa
  • 6K1: 5 kDa
  • Cl (helicase): 71 kDa
  • 6K2: 6 kDa
  • VPg (the 5' binding protein): 20 kDa
  • NIa-Pro (a protease): 27 kDa
  • NIb (
    RNA dependent RNA polymerase
    ): 57 kDa
  • Capsid protein: 34 kDa

There may be some variation in the number of the proteins depending on the genera and species.

inosine triphosphate pyrophosphatase (known as ITPase or HAM1) are protein domains identified in atypical members.[7][8]

Life cycle

Replication and movement of soybean mosaic virus (SMV)

Viral replication is cytoplasmic. Entry into the host cell is achieved by penetration. Replication follows the positive-stranded RNA virus replication model. Positive-stranded RNA virus transcription is the method of transcription. Translation takes place by −1 ribosomal frameshifting. The virus exits the host cell by tubule-guided viral movement.[4][5] Plants serve as the natural host. The virus is transmitted via a vector (often an insect or mite). Transmission routes are vector and mechanical.[4][5]

Transmission

Potyvirus is the largest genus in the family, with 183 known species.[9] These viruses are 720–850 nm in length and are transmitted by aphids. They can also be easily transmitted by mechanical means. These viruses shared a common ancestry 6,600 years ago[10] and are transmitted by over 200 species of aphids.[citation needed]

The species in the genus Macluravirus are 650–675 nm in length and are also transmitted by aphids. The plant viruses in the genus Ipomovirus are transmitted by

chytrid fungus, Polymyxa graminis.[citation needed
]

Taxonomy

Phylogenetic tree of family Potyviridae

The following genera are recognized:[6]

The following species are unassigned to a genus:[6]

References

  1. PMID 1730931
    .
  2. ^ Berger PH, et al. (2005) in Virus Taxonomy: Eighth Report of the InternationalCommittee on the Taxonomy of Viruses, eds Fauquet CM, Mayo MA, Maniloff J, Desselberger U, Ball LA (Elsevier Academic, San Diego), pp 819–841.
  3. PMID 28366187
    .
  4. ^ a b c d e "Potyviridae". ICTV Online (10th) Report.
  5. ^ a b c d e "Viral Zone". ExPASy. Retrieved 15 June 2015.
  6. ^ a b c "Virus Taxonomy: 2020 Release". International Committee on Taxonomy of Viruses (ICTV). March 2021. Retrieved 21 May 2021.
  7. ^
    PMID 35195244
    .
  8. PMID 35700092
    .
  9. ^ Description of Plant Viruses: Family Potyviridae
  10. ^ Nigam D, LaTourrette K, Souza PFN, Garcia-Ruiz H (2019) Genome-wide variation in Potyviruses. Front Plant Sci 10:1439
  11. ^ Description of Plant Viruses: Family Potyviridae figure

External links

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