| Australian grapevine viroid | |
|---|---|
Virus classification  | |
| (unranked): | Viroid |
| Family: | Pospiviroidae |
| Genus: | Hostuviroid |
| Species: | |
| Strain: | Australian grapevine viroid |
The Australian grapevine viroid (abbreviated AGV), binomial name Apscaviroid austravitis [1] , is a type of grapevine viroid. [2]
Viroids are small single-stranded, circular RNAs that are infectious pathogens. Unlike viruses, they have no protein coating. All known viroids are inhabitants of angiosperms, and most cause diseases, whose respective economic importance to humans varies widely. A recent metatranscriptomics study suggests that the host diversity of viroids and other viroid-like elements is broader than previously thought and that it would not be limited to plants, encompassing even the prokaryotes.
Virus classification is the process of naming viruses and placing them into a taxonomic system similar to the classification systems used for cellular organisms.
A satellite is a subviral agent that depends on the coinfection of a host cell with a helper virus for its replication. Satellites can be divided into two major classes: satellite viruses and satellite nucleic acids. Satellite viruses, which are most commonly associated with plants, are also found in mammals, arthropods, and bacteria. They encode structural proteins to enclose their genetic material, which are therefore distinct from the structural proteins of their helper viruses. Satellite nucleic acids, in contrast, do not encode their own structural proteins, but instead are encapsulated by proteins encoded by their helper viruses. The genomes of satellites range upward from 359 nucleotides in length for satellite tobacco ringspot virus RNA (STobRV).
Theodor Otto Diener was a Swiss-American plant pathologist. In 1971, he discovered that the causative agent of the potato spindle tuber disease is not a virus, but a novel agent, which consists solely of a short strand of single-stranded RNA without a protein capsid, eighty times smaller than the smallest viruses. He proposed to name it, and similar agents yet to be discovered, viroids. Viroids displaced viruses as the smallest known infectious agents.
Pospiviroid is a genus of ssRNA viroids that infects plants, most commonly tubers. It belongs to the family Pospiviroidae. The first viroid discovered was a pospiviroid, the PSTVd species.
The Pospiviroidae are a incertae sedis family of ssRNA viroids with 5 genera and 39 species, including the first viroid to be discovered, PSTVd, which is part of genus Pospiviroid. Their secondary structure is key to their biological activity. The classification of this family is based on differences in the conserved central region sequence. Pospiviroidae replication occurs in an asymmetric fashion via host cell RNA polymerase, RNase, and RNA ligase. Its hosts are plants, specifically dicotyledons and some monocotyledons. The severity of the infection can vary from no effect to devastating and widespread damage to a population. This can also depend on the virus-host combination.
AGV, or agv, may refer to:
The International Committee on Taxonomy of Viruses (ICTV) authorizes and organizes the taxonomic classification of and the nomenclature for viruses. The ICTV develops a universal taxonomic scheme for viruses, and thus has the means to appropriately describe, name, and classify every virus taxon. The members of the International Committee on Taxonomy of Viruses are considered expert virologists. The ICTV was formed from and is governed by the Virology Division of the International Union of Microbiological Societies. Detailed work, such as identifying new taxa and delimiting the boundaries of species, genera, families, etc. typically is performed by study groups of experts in the families.
Avocado sunblotch viroid is a disease affecting avocado trees.
Nepovirus is a genus of viruses in the order Picornavirales, in the family Secoviridae, in the subfamily Comovirinae. Plants serve as natural hosts. There are 40 species in this genus. Nepoviruses, unlike the other two genera in the subfamily Comovirinae, are transmitted by nematodes.
Peach latent mosaic viroid is a species of the genus Pelamoviroid, which belongs to the family Avsunviroidae. This family is characterized as having chloroplastic viroids with hammerhead ribozymes. Peach latent mosaic viroid is a 336-351nt circular RNA which has a branched formation. This branched formation is stabilised by a pseudoknot between two kissing loops. Peach latent mosaic viroid was first described in the 1980s in Spain by a group of scientists.
The Avsunviroidae are a family of viroids. There are five species in three genera. They consist of RNA genomes between 246 and 375 nucleotides in length. They are single-stranded covalent circles and have intramolecular base pairing. All members lack a central conserved region.
The hop stunt viroid is a viroid species that infects the common hop plant, citrus plants, grapevines, cucumber, and several Prunus species such as almond, apricot, plum, and peach. It is asymptomatic or latent in most host plants, but in some hosts it can cause stunting and other symptoms. A study of HSVd-infected hops in the USA showed that the severity of yield reduction was highly dependent on the infected hop cultivar.
Hostuviroid is a genus of ssRNA viroids that includes Hop stunt viroid, a species of viroids that infects many different types of plants, including the common hop plant. It belongs to the family Pospiviroidae.
Vitivirus is a genus of viruses in the order Tymovirales, in the family Betaflexiviridae. Plants serve as natural hosts. There are 15 species in this genus.
Grapevine yellow speckle viroid 1 is a type of viroid that infects grapevine.
Apscaviroid is a genus of ssRNA viroids that belongs to the family Pospiviroidae.
Grapevine yellow speckle viroid can refer to two different species of viroid, both in the genus Apscaviroid:
In virology, realm is the highest taxonomic rank established for viruses by the International Committee on Taxonomy of Viruses (ICTV), which oversees virus taxonomy. Six virus realms are recognized and united by specific highly conserved traits:
Ribozyviria is a realm of satellite nucleic acids — infectious agents that resemble viruses, but cannot replicate without a helper virus. Established in ICTV TaxoProp 2020.012D, the realm is named after the presence of genomic and antigenomic ribozymes of the Deltavirus type. The agents in Ribozyviria are satellite nucleic acids, which are distinct from satellite viruses in that they do not encode all of their own structural proteins but require proteins from their helper viruses in order to assemble. Additional common features include a rod-like structure, an RNA-binding "delta antigen" encoded in the genome, and animal hosts. Furthermore, the size range of the genomes of these viruses is between around 1547–1735nt, they encode a hammerhead ribozyme or a hepatitis delta virus ribozyme, and their coding capacity only involves one conserved protein. Most lineages of this realm are poorly understood, the notable exception being the genus Deltavirus, comprising the causal agents of hepatitis D in humans.
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