pathogenic virus
A viral disease (or viral infection) occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles (virions) attach to and enter susceptible cells.
Structural Characteristics
Basic structural characteristics, ...
es in the order ''
Tymovirales
''Tymovirales'' is an order of viruses with five families. The group consists of viruses which have positive-sense, single-stranded RNA genomes. Their genetic material is protected by a special coat protein.
Description
Tymoviruses are mainly ...
'', in the family ''
Alphaflexiviridae
''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 sy ...
''. 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'').
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:
* Subgenus: '' Mandarivirus''
** ''
Citrus yellow mottle-associated virus
''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native to ...
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** ''
Citrus yellow vein clearing virus
''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native ...
Babaco mosaic virus
The babaco (''Vasconcellea'' × ''heilbornii''; syn. ''Carica pentagona''), is a hybrid cultivar in the genus '' Vasconcellea'' from Ecuador. It is a hybrid between '' Vasconcellea cundinamarcensis'' (syn. ''Carica pubescens'', "mountain papaya ...
Cactus virus X
Cactus virus X (CVX) is a plant pathogenic virus of the family ''Alphaflexiviridae
''Alphaflexiviridae'' is a family of viruses in the order ''Tymovirales
''Tymovirales'' is an order of viruses with five families. The group consists of virus ...
''
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Cassava Colombian symptomless virus
''Manihot esculenta'', commonly called cassava (), manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America. Although a perennial plant, cassava is extensively cultivated a ...
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Cassava common mosaic virus
Cassava common mosaic virus (CsCMV) is a plant pathogenic virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to micr ...
Cnidium virus X
''Cnidium'' is a genus of flowering plants in the family Apiaceae, native to Eurasia and North America.
Species
, Plants of the World Online
Plants of the World Online (POWO) is an online database published by the Royal Botanic Gardens, Kew. ...
Euonymus yellow vein virus
''Euonymus'' is a genus of flowering plants in the staff vine family, Celastraceae. Common names vary widely among different species and between different English-speaking countries, but include spindle (or spindle tree), burning-bush, straw ...
Lagenaria mild mosaic virus
''Lagenaria'' is a genus of gourd-bearing vines in the squash family (Cucurbitaceae). ''Lagenaria'' contains six species, all of which are indigenous to tropical Africa.Lettuce virus X''
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Lily virus X
Lily virus X (LVX) is a pathogenic ssRNA(+) plant virus of the family ''Alphaflexiviridae'' and the order ''Tymovirales''.
Description
LVX is described in the 4th report of the International Committee on Taxonomy of Viruses, ICTV (1982). It is ...
''
*''
Malva mosaic virus
''Malva mosaic virus'' is a plant pathogenic virus of the family '' Alphaflexiviridae''. It was discovered in 2008 and infects the common mallow (''Malva neglecta''). Its genome is about 6,800 nucleotides in length and it contains five major open ...
Papaya mosaic virus
''Papaya mosaic virus'' (PapMV) is a plant pathogenic virus in the genus ''Potexvirus'' and the family ''Alphaflexiviridae''. PapMV is a filamentous, flexuous rod, 530 nm in length.
The virus is a monopartite strand of positive-sense, sing ...
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Pepino mosaic virus
''Solanum muricatum'' is a species of evergreen shrub native to South America and grown for its sweet edible fruit.
It is known as ''pepino dulce'' ("sweet cucumber" in English, in order to differentiate it from cucumber which is also called " ...
Potato virus X
Potato virus X (PVX) is a plant pathogenic virus of the family ''Alphaflexiviridae'' and the order ''Tymovirales''.
PVX is found mainly in potatoes and is only transmitted mechanically. There are no insect or fungal vectors for this virus. This v ...
Senna mosaic virus
Senna may refer to:
Individuals
* Ayrton Senna (1960–1994), Brazilian F1 driver and triple World Champion
* Bruno Senna (born 1983), F1 driver and nephew of Ayrton Senna
* Danzy Senna (born 1970), novelist
* Lorraine Senna, American film and ...
Tamus red mosaic virus
''Dioscorea'' is a genus of over 600 species of flowering plants in the family Dioscoreaceae, native throughout the tropical and warm temperate regions of the world. The vast majority of the species are tropical, with only a few species extendin ...
''
*''
Tulip virus X
Tulips (''Tulipa'') are a genus of spring-blooming perennial herbaceous bulbiferous geophytes (having bulbs as storage organs). The flowers are usually large, showy and brightly coloured, generally red, pink, yellow, or white (usually in warm ...
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Turtle grass virus X
Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...
Yam virus X
Yam or YAM may refer to:
Plants and foods
*Yam (vegetable), common name for members of ''Dioscorea''
* Taro, known in Malaysia and Singapore as yam
*Sweet potato, specifically its orange-fleshed cultivars, often referred to as yams in North Ameri ...
virion
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's ...
length may vary considerably (between 470-1000 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.
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
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to ...
, three proteins - the triple gene block (TGB) 1, 2 and 3 - and the coat protein.
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.
In addition to its RNA polymerase activity, the viral RNA polymerase (molecular weight ~150 kilo
Dalton
Dalton may refer to:
Science
* Dalton (crater), a lunar crater
* Dalton (program), chemistry software
* Dalton (unit) (Da), the atomic mass unit
* John Dalton, chemist, physicist and meteorologist
Entertainment
* Dalton (Buffyverse), minor cha ...
s) also has
methyltransferase
Methyltransferases are a large group of enzymes that all methylate their substrates but can be split into several subclasses based on their structural features. The most common class of methyltransferases is class I, all of which contain a Ross ...
and
RNA helicase
Helicases are a class of enzymes thought to be vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separati ...
activities.
The TGB proteins are conserved among the Allexivirus,
Carlavirus
''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 w ...
, 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 endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough 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.
Hosts
Known hosts are various
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...