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An infectious particle, similar to but smaller than a virus, that consists solely of a strand of RNA and is capable of causing disease in plants.


(Biochemistry) any of various infective RNA particles, smaller than a virus and known to cause some plant diseases
[C20: from vir(us) + -oid]


(ˈvaɪ rɔɪd)

an infectious agent of plants similar to a virus but consisting of only a short, single strand of RNA without a protein coat.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.viroid - the smallest of viruses; a plant virus with its RNA arranged in a circular chromosome without a protein coat
plant virus - a plant pathogen that is a virus consisting of a single strand of RNA
References in periodicals archive ?
Thus the archaea and viroid induced Warburg phenotype can contribute to the pathogenesis of schizophrenia, autism and primary seizure disorder.
Grasmick ME and SA Slack Detection of potato spindle tuber viroid in true potato seed by bioassay on Rutgers tomato.
section] 7702(14) (2006) (defining plant pests as "any living stage of any of the following that can directly or indirectly injure, cause damage to, or cause disease in any plant or plant product: (A) A protozoan (B) A nonhuman animal (C) A parasitic plant (D) A bacterium (E) A fungus (F) A virus or viroid (G) An infectious agent or other pathogen (H) Airy article similar to or allied with any of the articles specified in the preceding subparagraphs"); id.
Botanists and agricultural scientists examine virus, viroid, and phytoplasma diseases of both the apple family and the peach family of fruits, because many of the diseases affect both groups.
3-5) There was an increase in free RNA indicating self replicating RNA viroids and free DNA indicating generation of viroid complementary DNA strands by archaeal reverse transcriptase activity.
Among the terms he defines are crop rotation, habitat, low-temperature acclimatisation, quantitative genetics, translocation tester set, and viroid.
The researchers have developed an experimental system to identity specific structural parts of a viroid that are responsible for its multiplication and spread of the disease.
There is also a complex selection of horticultural pests and diseases, including the tobacco or sweet potato whitefly, bemisia tabaci and other glasshouse insects, the pepino mosaic virus - which hits tomatoes - potato spindle tuber viroid and angular leaf spot on strawberries.
A serious viroid disease, cadang cadang, which devastates coconut palms, was found be transmitted between them by bolo knives.
However, despite the impressive studies, Bigornia (1977) was of the opinion that "until in-effectivity of the RNAs is conclusively demonstrated through experimental transmission, the characterization of the ccRNA-1 and ccRNA-2 and their more or less constant association with diseased condition can only be regarded as indirect supporting evidence for the viroid hypothesis of cadang-cadang.
Because researchers are unsure about how to classify them, various names have been ascribed for them, such as slow virus, virino, viroid, virion and prion, or proteinaceous infectious particle.
Another USDA scientist found the first viroid ever identified by scientists when studying potato spindle tuber disease, which is transmitted in tubers and seed.