Potato virus X (PVX) is a plant pathogenic virus of 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 ...
'' and 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 ...
''.
PVX is found mainly in
potato
The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae.
Wild potato species can be found from the southern Unit ...
es and is only transmitted mechanically. There are no insect or fungal vectors for this virus. This virus causes mild or no symptoms in most potato varieties, but when
Potato virus Y
Potato virus Y (PVY) is a plant pathogenic virus of the family ''Potyviridae'', and one of the most important plant viruses affecting potato production.
PVY infection of potato plants results in a variety of symptoms depending on the viral stra ...
is present, synergy between these two viruses causes severe symptoms in potatoes. The virion has helical symmetry and a deeply grooved, highly hydrated surface and is made of a single-stranded positive-sense RNA genome of approximately 6.4 kb. This is wrapped in approximately 1300 units of a single coat protein (CP) type, with 8.9 CP units per helix turn. The genome is capped at the 5′-end and poly-adenylated at the 3′-terminus. It contains five open reading frames (ORFs) encoding five proteins: the RNA-dependent RNA Polymerase (RdRP), the movement proteins encoded by three overlapping ORFs that form the Triple Gene Block module (TGBp1, TGBp2, and TGBp3), and the CP (coat protein).
Virus indexing and limited generation production of potato, which starts from disease-free tissue culture plantlets, has nearly eliminated this virus from many countries' potato supply.
Hosts
''
Solanum tuberosum
The potato is a starch#Food, starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial plant, perennial in the nightshade family Solanaceae.
Wild potato species can be fo ...
'', ''
Lycopersicon esculentum
The tomato is the edible berry of the plant ''Solanum lycopersicum'', commonly known as the tomato plant. The species originated in western South America, Mexico, and Central America. The Mexican Nahuatl word gave rise to the Spanish word , ...
'' and ''
Nicotiana tabacum
''Nicotiana tabacum'', or cultivated tobacco, is an annually grown herbaceous plant of the ''Nicotiana'' genus. The plant is tropical in origin, is commonly grown throughout the world, and is often found in cultivation. It grows to heights bet ...
''.
Use in research
Chapman et al. 1992 introduced the use of
transgenic
A transgene is a gene that has been transferred naturally, or by any of a number of genetic engineering techniques, from one organism to another. The introduction of a transgene, in a process known as transgenesis, has the potential to change the ...
PVX as a
plant transformation vector
Plant transformation vectors are plasmids that have been specifically designed to facilitate the generation of transgenic plants. The most commonly used plant transformation vectors are termed binary vectors because of their ability to replicat ...
.
It has since been used by Kumagai et al. 1995 in the discovery of what is now known as
virus-induced gene silencing
RNA interference (RNAi) is a biological process in which RNA molecules are involved in sequence-specific suppression of gene expression by double-stranded RNA, through translational or transcriptional repression. Historically, RNAi was known by o ...
, by Thomas et al. 2001 to improve Kumagai's process, by De Kock et al. 2004 to investigate ''
Nicotiana
''Nicotiana'' () is a genus of herbaceous plants and shrubs in the Family (biology), family Solanaceae, that is Native plant, indigenous to the Americas, Australia, Southwestern Africa and the South Pacific. Various ''Nicotiana'' species, common ...
''s
Cf proteins and
Cf genes and their production of
host resistance responsive to pathogen
extracellular protein 2 (ECP2) (and by others to investigate various other
hostpathogen interactions in ''S. tuberosum'', ''L. esculentum'' and ''N. tabacum'')
and by Tameling et al. 2007 to investigate plant
nucleotide binding leucine-rich repeats (NB-LRRs).
See also
*
Viral diseases of potato
Viral diseases of potato are a group of diseases caused by different types of viruses that affect potato crops worldwide and, although they do not affect human or animal health since they are viruses that only infect vegetables, they are a source o ...
References
External links
ICTVdB—The Universal Virus Database: Potato virus X—The Two-Faced Potato Virus X: From Plant Pathogen to Smart Nanoparticle
Potexviruses
Viral plant pathogens and diseases
{{Virus-plant-disease-stub