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Encyclopedia > Potato spindle tuber viroid
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Potato spindle tuber viroid

Virus classification
(unranked) Subviral agents
(unranked) Viroid
Order: none
Family: Pospiviroidae
Genus: Pospiviroid
Species: PSTVd
Type species
Potato spindle tuber viroid

The Potato spindle tuber viroid (PSTVd) was the first viroid to be identified. PSTVd is a small, circular RNA molecule closely related to the Chrysanthemum stunt viroid. The natural hosts are potatoes (Solanum tuberosum) and tomatoes (Lycopersicon esculentum). All potatoes and tomatoes are susceptible to PSTVd and there is no form of natural resistance. Natural infections have also been seen in avocados and infections in other solanaceous crops have been induced in the laboratory. Image File history File links Wikitext. ... Virus classification involves naming and placing viruses into a taxonomic system. ... Virus classification involves naming and placing viruses into a taxonomic system. ... Families Pospiviroidae Avsunviroidae Viroids are plant pathogens that consist of a short stretch (a few hundred nucleobases) of highly complementary, circular, single-stranded RNA without the protein coat that is typical for viruses. ... Genera Pospiviroid Hostuviroid Cocadviroid Apscaviroid Coleviroid The Pospiviroidae is a family of viroids. ... Species (PSTV) Potato spindle tuber viroid The Pospiviroid is a genus of viroid which most commonly infects tubers. ... A type species fixes the name of a genus (or of a taxon in a rank lower than genus). ... Families Pospiviroidae Avsunviroidae Viroids are plant pathogens that consist of a short stretch (a few hundred nucleobases) of highly complementary, circular, single-stranded RNA without the protein coat that is typical for viruses. ... Binomial name Solanum tuberosum L. The potato (Solanum tuberosum) is a perennial plant of the Solanaceae, or nightshade, family, grown for its starchy tuber. ... For other uses, see Tomato (disambiguation). ...


Different strains of PSTVd exist and symptoms range from mild to severe. Mild strains produce no obvious symptoms. Symptoms in severe strains are dependent on environmental conditions and are most severe in hot conditions. Symptoms may be mild in initial infections but become progressively worse in the following generations. Common symptoms of severe infections include colour changes in the foliage, smaller leaves and spindle like elongation. Sprouting also occurs at a slower rate than in unaffected potatoes. Infected tomatoes are slower to show symptoms which include stunted growth with a ‘bunchy top’ caused by shortened internodes. Leaves become yellow or purple and often become curled and twisted. Necrosis eventually occurs in the veins of the bottom and middle leaves and the top leaves don’t die but are reduced in size. Fruit ripening is also affected leading to hard, small, dark green tomatoes.


Long distance spread of PSTVd usually occurs via infected seeds but transmission via aphids (Myzus persicae) also occurs but only in the presence of PLRV (potato leaf roll virus). Mechanical transmission also occurs once it has been introduced to an area.

Contents

Primary and secondary structure of the PSTVd viroid

The PSTVd viroid has 359 nucleotides.

Primary Structure


 1 CGGAACUAAA CUCGUGGUUC CUGUGGUUCA CACCUGACCU CCUGAGCAGA AAAGAAAAAA 61 GAAGGCGGCU CGGAGGAGCG CUUCAGGGAU CCCCGGGGAA ACCUGGAGCG AACUGGCAAA 121 AAAGGACGGU GGGGAGUGCC CAGCGGCCGA CAGGAGUAAU UCCCGCCGAA ACAGGGUUUU 181 CACCCUUCCU UUCUUCGGGU GUCCUUCCUC GCGCCCGCAG GACCACCCCU CGCCCCCUUU 241 GCGCUGUCGC UUCGGCUACU ACCCGGUGGA AACAACUGAA GCUCCCGAGA ACCGCUUUUU 301 CUCUAUCUUA CUUGCUUCGG GGCGAGGGUG UUUAGCCCUU GGAACCGCAG UUGGUUCCU 
Secondary Structure


Putative secondary structure of the PSTVd viroid
Putative secondary structure of the PSTVd viroid

The nucleotides which are highlighted are found in most other viroids. Download high resolution version (1184x86, 6 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1184x86, 6 KB) Wikipedia does not have an article with this exact name. ...


There are several strain of the PSTVd viroid known. More can be found at [Organism:noexp&cmd=Search&db=nuccore&QueryKey=3 NCDI].


See also

External links

References

  • [1] defra Plant Health

  Results from FactBites:
 
Viroids and Virusoids (1325 words)
Viroids, virusoids and prions are unusual infectious agents characterised by having a very small genome and in the case of prions, possibly no genome at all.
Recent evidence suggests that one pathway is due to viroid RNA activating a plant RNA activated protein kinase, or PKR (analogous to the PKR enzyme activated by viral RNAs in mammalian cells).
In the case of potato spindle tuber viroid, there is a good correlation between a strains pathogenicity and its ability to activate PKR in vitro.
  More results at FactBites »

 
 

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