Potyvirus
Encyclopedia
Potyviruses infect plants and belong to the family Potyviridae
Potyviridae
The Potyviridae are a family of plant viruses. They are . Their genome is composed 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 in their hosts...

. The genus is named after the type virus - Potato Virus Y.

The Potyvirus, like the Begomovirus
Begomovirus
The genus Begomovirus contains more than 200 species and belongs to the taxonomic family Geminiviridae. They are plant viruses that as a group have a very wide host range, infecting dicotyledonous plants...

es, have ~30% of the currently known plant viruses and have at least 180 definitive and possible members. Members of this genus may cause significant losses in agricultural, pastural, horticultural and ornamental crops.

There are 73 described genera of plant viruses.

More than 200 species of aphids spread potyviruses and most are from the subfamily Aphidinae (genera Macrosiphum
Macrosiphum
Macrosiphum is a genus of aphid....

and Myzus).

Evolution

The potyviruses evolved between 6,600 to 7,250 years ago.

They appear to have evolved in southwest Eurasia or north Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

.

The estimated mutation rate is about 1.15×10−4 nucleotide substitutions/site/year.

Virology

The virion is non-enveloped with a filamentous nucleocapsid, 680 to 900 nanometers (nm) long and is 11-20 nm in diameter. The nucleocapsid contains ~2000 copies of the capsid protein. The symmetry of the nucleocapsid is helical with a pitch of 3.4 nm.

The genome is a linear positive sense ssRNA ranging in size from 9000-12000bp. A number of species have a bipartate genome.The base composition is: 21-23.51-26% G; 23-30.15-44% A; 14.9-22.41-28% C; 15.6-24.41-30.9% U.

In the species with a single genome, at the 5' end a protein is covalently linked (the Vg protein). It encodes a single open reading frame (ORF) expressed as a 350kDa polyprotein precursor. This is processed into seven smaller proteins: P1, helper component (HC), P3, cylindrical inclusion (CI), nuclear inclusion A (NIa), nuclear inclusion B (NIb), capsid protein (CP) and two small putative proteins known as 6K1 and 6K2. The P3 protein also encodes a second protein - P3N-PIPO - which is generated by a +2 frameshift.

Molecular biology

Protein P1 (~33 kiloDaltons (kDa) in molecular weight) is a serine
Serine
Serine is an amino acid with the formula HO2CCHCH2OH. It is one of the proteinogenic amino acids. By virtue of the hydroxyl group, serine is classified as a polar amino acid.-Occurrence and biosynthesis:...

 protease
Protease
A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....

.

HC (~52 KDa) is a protease that is also involved in aphid transmission. As a protease it cleaves a glycine
Glycine
Glycine is an organic compound with the formula NH2CH2COOH. Having a hydrogen substituent as its 'side chain', glycine is the smallest of the 20 amino acids commonly found in proteins. Its codons are GGU, GGC, GGA, GGG cf. the genetic code.Glycine is a colourless, sweet-tasting crystalline solid...

-glycine dipeptide at its own C terminus. It also interacts with eukaryotic initiation factor 4 (eIF4). It acts as a viral RNA silencing suppressor.

The function of P3 (~41 kDa) is not known. It interacts with large subunit of the ribulose-1,5-bisphosphate carboxylase/oxygenase.

CI (~71 kDa) is an RNA helicase
Helicase
Helicases are a class of enzymes vital to all living organisms. They are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands using energy derived from ATP hydrolysis.-Function:Many cellular processes Helicases are a...

 with ATPase
ATPase
ATPases are a class of enzymes that catalyze the decomposition of adenosine triphosphate into adenosine diphosphate and a free phosphate ion. This dephosphorylation reaction releases energy, which the enzyme harnesses to drive other chemical reactions that would not otherwise occur...

 activity. It is also involved in membrane attachment.

NIa (~50 kDa) is cleaved into a protease (~27 kDa) and the Vg (~22 kDa) protein.

NIb (~59 kDa) is an RNA-dependent RNA polymerase
RNA-dependent RNA polymerase
RNA-dependent RNA polymerase , , or RNA replicase, is an enzyme that catalyzes the replication of RNA from an RNA template...

.

The functions of the 6K1 (~6 kDa) and 6K2 (~6 kDa) are not known.

The function of the P3N-PIPO (~25 kDa) is not known but it appears to be essential. It interacts with both the large and small subunits of the ribulose-1,5-bisphosphate carboxylase/oxygenase.

The capsid protein ranges between 30 and 35 kDa in weight.

The VPg protein interacts with eukaryotic initiation factor
Eukaryotic initiation factor
Eukaryotic initiation factors are proteins involved in the initiation phase of eukaryotic translation. They function in forming a complex with the 40S ribosomal subunit and Met-tRNAi called the 43S preinitation complex , recognizing the 5' cap structure of mRNA and recruiting the 43S PIC to mRNA,...

 4 (eIF4). This interaction appears to be essential.

Two proteinases, P1 and the helper component proteinase (HC) catalyse only autoproteolytic reactions at their respective C termini. The remaining cleavage reactions are catalysed by either trans-proteolytic or autoproteolytic mechanisms by the small nuclear inclusion protein (NIa-Pro). This latter protein is an evolutionary homology of the picornavirus
Picornavirus
A picornavirus is a virus belonging to the family Picornaviridae. Picornaviruses are non-enveloped, positive-stranded RNA viruses with an icosahedral capsid. The genome RNA is unusual because it has a protein on the 5' end that is used as a primer for transcription by RNA polymerase...

 3C proteinase.

Life cycle

Replication may occur in the cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

, nuclei
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

, chloroplast
Chloroplast
Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis.Chloroplasts are green...

s, Golgi apparatus
Golgi apparatus
The Golgi apparatus is an organelle found in most eukaryotic cells. It was identified in 1898 by the Italian physician Camillo Golgi, after whom the Golgi apparatus is named....

, cell vacuoles or more rarely in unusual sites. Inclusions are usually found in infected cells. These may be crystals in either the cytoplasm or in the nucleus as amorphous X-bodies, membranous bodies, viroplasms or pinwheels. These inclusions may or may not (depending on the species) contain virions.

Species

Alstroemeria mosaic potyvirus

Amaranthus leaf mottle potyvirus

Apium virus Y
Apium virus Y
Apium virus Y is a plant pathogenic virus in the genus Potyvirus and the virus family Potyviridae .Apium virus Y is a recently described member of the potyvirus family. It was first found in Australia in 2002 in poison hemlock...



Araujia mosaic potyvirus

Arracacha Y potyvirus

Artichoke latent potyvirus

Asparagus 1 potyvirus

Banana bract mosaic potyvirus

Bean common mosaic necrosis potyvirus

Bean common mosaic potyvirus

Bean yellow mosaic potyvirus

Beet mosaic potyvirus

Bidens mosaic potyvirus

Bidens mottle potyvirus

Canna yellow streak virus

Cardamom mosaic potyvirus

Carnation vein mottle potyvirus

Carrot thin leaf potyvirus

Cassava brown streak potyvirus

Cassia yellow spot potyvirus

Celery mosaic potyvirus

Chickpea bushy dwarf potyvirus

Chickpea distortion mosaic potyvirus

Chilli ringspot virus

Chili veinal mottle virus

Clitoria chlorosis virus

Clover yellow vein potyvirus

Cocksfoot streak virus

Commelina diffusa potyvirus

Commelina mosaic potyvirus

Cowpea green vein-banding potyvirus

Cowpea Moroccan aphid-borne mosaic potyvirus

Cowpea rugose mosaic potyvirus

Crinum mosaic potyvirus

Daphne Y potyvirus

Dasheen mosaic potyvirus

Datura Colombian potyvirus

Datura distortion mosaic potyvirus

Datura necrosis potyvirus

Datura shoestring potyvirus

Dendrobium mosaic potyvirus

Desmodium mosaic potyvirus

Dioscorea alata potyvirus

Dioscorea green banding mosaic potyvirus

Eggplant green mosaic potyvirus

Euphorbia ringspot potyvirus

Freesia mosaic potyvirus

Groundnut eyespot potyvirus

Guar symptomless potyvirus

Guinea grass mosaic potyvirus

Hardenbergia mosaic virus

Helenium Y potyvirus

Henbane mosaic potyvirus

Hippeastrum mosaic potyvirus

Hyacinth mosaic potyvirus

Iris fulva mosaic potyvirus

Iris mild mosaic potyvirus

Iris severe mosaic potyvirus

Japanese hornwort mosaic virus

Johnsongrass mosaic virus
Johnsongrass mosaic virus
Johnsongrass mosaic virus is a plant pathogenic virus of the family Potyviridae. It is a known pathogen of the major grain crop maize.-External links:**...



Kennedya Y potyvirus

Leek yellow stripe potyvirus

Lettuce mosaic potyvirus

Lily mottle potyvirus

Lupine potyvirus

Maize dwarf mosaic potyvirus

Malva vein clearing potyvirus

Marigold mottle potyvirus

Narcissus yellow stripe potyvirus

Nerine potyvirus

Onion yellow dwarf potyvirus

Ornithogalum mosaic potyvirus

Papaya ringspot potyvirus

Parsnip mosaic potyvirus

Passiflora mosaic virus

Passiflora ringspot potyvirus

Passiflora South African potyvirus

Passiflora virus Y

Passionfruit woodiness potyvirus

Patchouli mosaic potyvirus

Pea mosaic potyvirus

Pea seed-borne mosaic potyvirus

Peanut green mosaic potyvirus

Peanut mottle potyvirus

Pepper Indian mottle potyvirus

Pepper mottle potyvirus

Pepper severe mosaic potyvirus

Pepper veinal mottle potyvirus

Plum pox potyvirus

Pokeweed mosaic potyvirus

Potato A potyvirus

Potato V potyvirus

Potato Y potyvirus (type species)

Primula mosaic potyvirus

Ranunculus mottle potyvirus

Shallot yellow stripe potyvirus

Sorghum mosaic potyvirus

Soybean mosaic potyvirus

Statice Y potyvirus

Sugarcane mosaic potyvirus

Sweet potato feathery mottle potyvirus

Sweet potato G potyvirus

Swordbean distortion mosaic potyvirus

Sunflower chlorotic mottle virus

Tamarillo mosaic potyvirus

Telfairia mosaic potyvirus

Tobacco etch potyvirus

Tobacco vein-banding mosaic potyvirus

Tobacco vein mottling potyvirus

Tobacco wilt potyvirus

Tomato Peru potyvirus

Tradescantia-Zebrina potyvirus

Triteleia mosaic virus

Tropaeolum 1 potyvirus

Tropaeolum 2 potyvirus

Tuberose potyvirus

Tulip band-breaking potyvirus

Tobacco vein banding mosaic virus

Tulip breaking potyvirus

Tulip chlorotic blotch potyvirus

Turnip mosaic potyvirus

Tradescantia mosaic virus
Tradescantia mosaic virus
Tradescantia mosaic virus is a plant pathogenic virus in the genus Potyvirus and the virus family Potyviridae. Like other members of the Potyvirus genus, TZV is a monopartite strand of positive-sense, single-stranded RNA surrounded by a capsid made for a single viral encoded protein. The virus...



Ullucus mosaic potyvirus

Vallota mosaic potyvirus

Vanilla mosaic potyvirus

Vanilla necrosis potyvirus

Voandzeia distortion mosaic potyvirus

Watermelon mosaic 1 potyvirus

Watermelon mosaic 2 potyvirus

Wild potato mosaic potyvirus

Wisteria vein mosaic potyvirus

Yam mosaic potyvirus

Zucchini yellow fleck potyvirus

Zucchini yellow mosaic potyvirus

Possible additional viruses

A number of viruses that have not been fully characterised may also belong in this genus:

Asystasia gangetica mottle potyvirus

Celery latent potyvirus

Datura mosaic potyvirus

Endive necrotic mosaic potyvirus

Kalanchoe mosaic potyvirus

Konjak mosaic potyvirus

Nasturtium mosaic potyvirus

Patchouli mottle potyvirus

Shallot yellow stripe potyvirus

Sweet potato vein mosaic potyvirus

Welsh onion yellow stripe potyvirus

Geographical spread

Agriculture was introduced into Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

in the 18th century. This introduction also included plant pathogens. Thirty eight potyvirus species have been isolated in Australia. Eighteen potyviruses have been found only in Australia and are presumed to be endemic there. The remaining twenty appear to have been introduced with agriculture.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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