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viroid
viroid Any of various small naked single-stranded RNA molecules that infect plant cells and cause disease. Smaller than viruses, viroids are not enclosed in a protein coat of any kind: they generally consist of less than 400 nucleotides and do not contain any genes. The circular RNA strand undergoes extensive base pairing within itself, forming a double-stranded structure that mimics DNA and is apparently replicated by the host cell's enzymes. This behaviour is similar to that of certain introns, prompting the suggestion that viroids are escaped introns. Viroids include many commercially important disease agents, such as coconut cadang-cadang, citrus exocortis, and potato spindle tuber viroid.
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"viroid." A Dictionary of Biology. 2004. Encyclopedia.com. 9 Feb. 2012 <http://www.encyclopedia.com>. "viroid." A Dictionary of Biology. 2004. Encyclopedia.com. (February 9, 2012). http://www.encyclopedia.com/doc/1O6-viroid.html "viroid." A Dictionary of Biology. 2004. Retrieved February 09, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-viroid.html |
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viroid
viroid microscopic infectious agent, much smaller than a virus , that infects higher plants such as potatoes, tomatoes, chrysanthemums, and cucumbers, causing stunted or distorted growth and sometimes death. It can be transmitted by pollen, seed, or farm implements. Viroids are single strands of RNA and lack the protein coat of viruses. They do not code for any specific protein but are able to replicate themselves in the nuclei of infected cells. Some scientists believe viroids are parts of normal RNA that have gone awry. Potato spindle tuber viroid was the first to be identified. |
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"viroid." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 9 Feb. 2012 <http://www.encyclopedia.com>. "viroid." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 9, 2012). http://www.encyclopedia.com/doc/1E1-viroid.html "viroid." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 09, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-viroid.html |
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viroid
viroid A piece of infectious nucleic acid. Viroids appear to resemble viruses in some respects, but consist only of small. closed circles of RNA: there is no capsid. They can cause disease in plants (e.g. potato spindle tuber disease and hop stunt).
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Cite this article
MICHAEL ALLABY. "viroid." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 9 Feb. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "viroid." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (February 9, 2012). http://www.encyclopedia.com/doc/1O7-viroid.html MICHAEL ALLABY. "viroid." A Dictionary of Plant Sciences. 1998. Retrieved February 09, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-viroid.html |
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