Potyviridae

The Potyviridae are a family of viruses that encompasses more than 30% of known plant viruses,[1][2] many of which are of great agricultural significance. Currently, more than 190 species are placed in this family, divided among eight genera.[3][4][5]

Potyviridae
Virus classification
(unranked): Virus
Realm: Riboviria
Phylum: incertae sedis
Family: Potyviridae
Genera

Taxonomy

Based on the amino acid sequences of their coat proteins, potyviruses are now divided into eight genera. All but the genus Bymovirus are single-stranded particles.[4]

Group: ssRNA(+)

[4]

Potyvirus is the largest genus in the family, with more than 167 known species.[6] 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[7] and are transmitted by over 200 species of aphids.

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 whiteflies and they are 750–950 nm long.

Tritimovirus and the Rymovirus viruses are 680–750 nm long and are transmitted by eriophydid mites. (The rymoviruses are closely related to the potyviruses and may eventually be merged with the potyviruses.[8])

The Bymovirus genome consists of two particles instead of one (275 and 550 nm) and these viruses are transmitted by the chytrid fungus, Polymyxa graminis.

Structure

They are nonenveloped, flexuous filamentous, rod-shaped particles. The diameter is around 12–15 nm, with a length of 200–300 nm.[4][5]

Genomes are linear and not segmented, bipartite, 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.

GenusStructureSymmetryCapsidGenomic arrangementGenomic segmentation
PotyvirusFilamentousNonenvelopedLinearMonopartite
IpomovirusFilamentousNonenvelopedLinearSegmented
BrambyvirusFilamentousNonenvelopedLinearMonopartite
TritimovirusFilamentousNonenvelopedLinearSegmented
RymovirusFilamentousNonenvelopedLinearSegmented
BymovirusFilamentousNonenvelopedLinearSegmented
PoacevirusFilamentousNonenvelopedLinearMonopartite
MacluravirusFilamentousNonenvelopedLinearSegmented

Lifecycle

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]

GenusHost detailsTissue tropismEntry detailsRelease detailsReplication siteAssembly siteTransmission
PotyvirusPlantsNoneViral movement; mechanical inoculationViral movementCytoplasmCytoplasmMechanical inoculation: aphids
IpomovirusPlantsNoneViral movement; mechanical inoculationViral movementCytoplasmCytoplasmMechanical inoculation: white fly
BrambyvirusPlantsNoneViral movement; mechanical inoculationViral movementCytoplasmCytoplasmMechanical inoculation: unknown vector
TritimovirusPlantsNoneViral movement; mechanical inoculationViral movementCytoplasmCytoplasmMechanical inoculation: mites
RymovirusPlantsNoneViral movement; mechanical inoculationViral movementCytoplasmCytoplasmMechanical inoculation: mites
BymovirusPlantsNoneViral movement; mechanical inoculationViral movementCytoplasmCytoplasmMechanical inoculation: fungus (Plasmodiophorales)
PoacevirusPlantsNoneViral movement; mechanical inoculationViral movementCytoplasmCytoplasmMechanical inoculation: wheat curl mite
MacluravirusPlantsNoneViral movement; mechanical inoculationViral movementCytoplasmCytoplasmMechanical inoculation: aphids

References
  1. Riechmann, JL; Lain, S; Garcia, JA (1992). "Highlights and prospects of potyvirus molecularbiology". J Gen Virol. 73: 1–16. doi:10.1099/0022-1317-73-1-1. 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. Wylie, SJ; Adams, M; Chalam, C; Kreuze, J; López-Moya, JJ; Ohshima, K; Praveen, S; Rabenstein, F; Stenger, D; Wang, A; Zerbini, FM; ICTV Report Consortium (March 2017). "ICTV Virus Taxonomy Profile: Potyviridae". The Journal of General Virology. 98 (3): 352–354. doi:10.1099/jgv.0.000740. PMC 5797945. PMID 28366187.
  4. "Potyviridae". ICTV Online (10th) Report.
  5. "Viral Zone". ExPASy. Retrieved 15 June 2015.
  6. Description of Plant Viruses: Family Potyviridae
  7. Nigam D, LaTourrette K, Souza PFN, Garcia-Ruiz H (2019) Genome-wide variation in Potyviruses. Front Plant Sci 10:1439
  8. Description of Plant Viruses: Family Potyviridae figure
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