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).
Sequivirus is a genus of viruses in the order Picornavirales, in the family Secoviridae. Plants serve as natural hosts. There are three species in this genus. Diseases associated with this genus include: PYFV: vein-yellowing, yellow flecks and yellow/green mosaic symptoms in parsnip, and ‘yellow net', followed by yellow spots and leaf distortion in celery.
Beta is a genus in the flowering plant family Amaranthaceae. The best known member is the common beet, Beta vulgaris, but several other species are recognised. Almost all have common names containing the word "beet". Wild Beta species can be found throughout the Atlantic coast of Europe, the Mediterranean coastline, the Near East, and parts of Asia including India.
Lettuce mosaic virus (LMV) is a typical potyvirus, which causes one of the major virus diseases of lettuce crops worldwide.
Potyvirus is a genus of positive-strand RNA viruses in the family Potyviridae. Plants serve as natural hosts. The genus is named after member virus potato virus Y. Potyviruses account for about thirty percent of the currently known plant viruses. Like begomoviruses, members of this genus may cause significant losses in agricultural, pastoral, horticultural, and ornamental crops. More than 200 species of aphids spread potyviruses, and most are from the subfamily Aphidinae. The genus contains 190 species.
Closterovirus, also known as beet yellows viral group, is a genus of viruses, in the family Closteroviridae. Plants serve as natural hosts. There are 17 species in this genus. Diseases associated with this genus include: yellowing and necrosis, particularly affecting the phloem. This genus has a probably worldwide distribution and includes among other viral species the Beet yellows virus and Citrus tristeza virus, rather economically important plant diseases. At least some species require vectors such as aphids or mealybugs for their transmission from plant to plant.
Beet curly top virus (BCTV) is a pathogenic plant virus of the family Geminiviridae, containing a single-stranded DNA. The family Geminiviridae consists of nine genera based on their host range, virus genome structure, and type of insect vector. BCTV is a Curtovirus affecting hundreds of plants. The only known vector is the beet leafhopper, which is native to the Western United States.
Beet necrotic yellow vein virus (BNYVV) is a plant virus, transmitted by the plasmodiophorid Polymyxa betae. The BNYVV is a member of the genus Benyvirus and is responsible for rhizomania, a disease of sugar beet that causes proliferation of thin rootlets, and leads to a smaller tap root with reduced sugar content. Infected plants are less able to take up water, and wilting can be observed during the warm period of the year. If the infection spreads to the whole plant, vein yellowing, necrosis and yellow spots appear on the leaves, giving the virus its name.
Beet yellows virus (BYV) is a plant pathogenic virus of the family Closteroviridae. Beet yellows virus is transmitted by multiple species of aphid and causes a yellowing disease in Beta vulgaris and Spinacia oleracea.
Sowthistle yellow vein virus (SYVV) is a plant-pathogenic virus of the family Rhabdoviridae. It infects the sowthistle, Sonchus oleraceous. As of May 2022, the formal species name is Betanucleorhabdovirus venasonchi.
Benyvirus is a genus of viruses, in the family Benyviridae. Plant serve as natural hosts. There are four species in this genus. Diseases associated with this genus include: BNYVV: rhizomania.
Orthotospovirus is a genus of negative-strand RNA viruses, in the family Tospoviridae of the order Bunyavirales, which infects plants. Tospoviruses take their name from the species Tomato spotted wilt orthotospovirus (TSWV) which was discovered in Australia in 1919. TSWV remained the only known member of the family until the early 1990s when genetic characterisation of plant viruses became more common. There are now at least twenty species in the genus with more being discovered on a regular basis. Member viruses infect over eight hundred plant species from 82 different families.
Apium virus Y (ApVY) is a plant pathogenic virus in the genus Potyvirus and the virus family Potyviridae.
Alphasatellites are a single-stranded DNA family of satellite viruses that depend on the presence of another virus to replicate their genomes. As such, they have minimal genomes with very low genomic redundancy. The genome is a single circular single strand DNA molecule. The first alphasatellites were described in 1999 and were associated with cotton leaf curl disease and Ageratum yellow vein disease. As begomoviruses are being characterised at the molecular level an increasing number of alphasatellites are being described.
Beet vascular necrosis and rot is a soft rot disease caused by the bacterium Pectobacterium carotovorum subsp. betavasculorum, which has also been known as Pectobacterium betavasculorum and Erwinia carotovora subsp. betavasculorum. It was classified in the genus Erwinia until genetic evidence suggested that it belongs to its own group; however, the name Erwinia is still in use. As such, the disease is sometimes called Erwinia rot today. It is a very destructive disease that has been reported across the United States as well as in Egypt. Symptoms include wilting and black streaks on the leaves and petioles. It is usually not fatal to the plant, but in severe cases the beets will become hollowed and unmarketable. The bacteria is a generalist species which rots beets and other plants by secreting digestive enzymes that break down the cell wall and parenchyma tissues. The bacteria thrive in warm and wet conditions, but cannot survive long in fallow soil. However, it is able to persist for long periods of time in the rhizosphere of weeds and non-host crops. While it is difficult to eradicate, there are cultural practices that can be used to control the spread of the disease, such as avoiding injury to the plants and reducing or eliminating application of nitrogen fertilizer.
Badnavirus is a genus of viruses, in the family Caulimoviridae order Ortervirales. Plants serve as natural hosts. There are 67 species in this genus. Diseases associated with this genus include: CSSV: leaf chlorosis, root necrosis, red vein banding in young leaves, small mottled pods, and stem/root swelling followed by die-back. Infection decreases yield by 25% within one year, 50% within two years and usually kills trees within 3–4 years.
Cytorhabdovirus is a genus of viruses in the family Rhabdoviridae, order Mononegavirales. Plants serve as natural hosts.
Polerovirus is a genus of viruses, in the family Solemoviridae. Plants serve as natural hosts. There are 26 species in this genus. Diseases associated with this genus include: PLRV causes prominent rolling of the leaves of potato and a stiff upright habit of the plants; necrosis of the phloem and accumulation of carbohydrates in the leaves.
Tymovirus is a genus of viruses in the order Tymovirales, in the family Tymoviridae. Plants serve as natural hosts. There are 28 species in this genus.
