Tobacco mosaic virus (TMV) is a positive-sense single-stranded RNA virus species in the genus Tobamovirus that infects a wide range of plants, especially tobacco and other members of the family Solanaceae. The infection causes characteristic patterns, such as "mosaic"-like mottling and discoloration on the leaves. TMV was the first virus to be discovered. Although it was known from the late 19th century that a non-bacterial infectious disease was damaging tobacco crops, it was not until 1930 that the infectious agent was determined to be a virus. It is the first pathogen identified as a virus. The virus was crystallised by W.M. Stanley.
Bunyavirales is an order of segmented negative-strand RNA viruses with mainly tripartite genomes. Member viruses infect arthropods, plants, protozoans, and vertebrates. It is the only order in the class Ellioviricetes. The name Bunyavirales derives from Bunyamwera, where the original type species Bunyamwera orthobunyavirus was first discovered. Ellioviricetes is named in honor of late virologist Richard M. Elliott for his early work on bunyaviruses.
Plant viruses are viruses that affect plants. Like all other viruses, plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. Plant viruses can be pathogenic to higher plants.
The Semliki Forest virus is an alphavirus found in central, eastern, and southern Africa. It was first isolated from mosquitoes in the Semliki Forest, Uganda by the Uganda Virus Research Institute in 1942 and described by Smithburn and Haddow. It is known to cause disease in animals including humans.
Alphavirus is a genus of RNA viruses, the sole genus in the Togaviridae family. Alphaviruses belong to group IV of the Baltimore classification of viruses, with a positive-sense, single-stranded RNA genome. There are 32 alphaviruses, which infect various vertebrates such as humans, rodents, fish, birds, and larger mammals such as horses, as well as invertebrates. Alphaviruses that could infect both vertebrates and arthropods are referred dual-host alphaviruses, while insect-specific alphaviruses such as Eilat virus and Yada yada virus are restricted to their competent arthropod vector. Transmission between species and individuals occurs mainly via mosquitoes, making the alphaviruses a member of the collection of arboviruses – or arthropod-borne viruses. Alphavirus particles are enveloped, have a 70 nm diameter, tend to be spherical, and have a 40 nm isometric nucleocapsid.
Furovirus is a genus of viruses, in the family Virgaviridae. Graminae, winter wheat, wheat, triticale, oat, sorghum bicolor, and plants serve as natural hosts. There are six species in this genus. Diseases associated with this genus include: (SBWMV): green and yellow mosaic.
A viroplasm, sometimes called "virus factory" or "virus inclusion", is an inclusion body in a cell where viral replication and assembly occurs. They may be thought of as viral factories in the cell. There are many viroplasms in one infected cell, where they appear dense to electron microscopy. Very little is understood about the mechanism of viroplasm formation.
Cowpea chlorotic mottle virus, known by the abbreviation CCMV, is a virus that specifically infects the cowpea plant, or black-eyed pea. The leaves of infected plants develop yellow spots, hence the name "chlorotic". Similar to its "brother" virus, Cowpea mosaic virus (CPMV), CCMV is produced in high yield in plants. In the natural host, viral particles can be produced at 1–2 mg per gram of infected leaf tissue. Belonging to the bromovirus genus, cowpea chlorotic mottle virus (CCMV) is a small spherical plant virus. Other members of this genus include the brome mosaic virus (BMV) and the broad bean mottle virus (BBMV).
Sindbis virus (SINV) is a member of the Togaviridae family, in the Alphavirus genus. The virus was first isolated in 1952 in Cairo, Egypt. The virus is transmitted by mosquitoes. SINV is linked to Pogosta disease (Finland), Ockelbo disease (Sweden) and Karelian fever (Russia). In humans, the symptoms include arthralgia, rash and malaise. Sindbis virus is widely and continuously found in insects and vertebrates in Eurasia, Africa, and Oceania. Clinical infection and disease in humans however has almost only been reported from Northern Europe, where SINV is endemic and where large outbreaks occur intermittently. Cases are occasionally reported in Australia, China, and South Africa.
Alfalfa mosaic virus (AMV), also known as Lucerne mosaic virus or Potato calico virus, is a worldwide distributed phytopathogen that can lead to necrosis and yellow mosaics on a large variety of plant species, including commercially important crops. It is the only Alfamovirus of the family Bromoviridae. In 1931 Weimer J.L. was the first to report AMV in alfalfa. Transmission of the virus occurs mainly by some aphids, by seeds or by pollen to the seed.
Panicum mosaic virus (PMV) is a positive-sense single-stranded RNA viral pathogen that infects plant species in the panicoid tribe of the grass family, Poaceae. The pathogen was first identified in Kansas in 1953 and most commonly causes disease on select cultivars of turf grass, switchgrass, and millet. The disease most commonly associated with the panicum mosaic virus pathogen is St. Augustine Decline Syndrome, which infects species of turf grass and causes chlorotic mottling. In addition to St. Augustine Decline, panicum mosaic virus is responsible for chlorotic streaking and mild green mosaicking in select cultivars of switchgrass and millet.
Potato mop-top virus (PMTV) is a plant pathogenic virus transmitted through the vector Spongospora subterranea that affects potatoes. PMTV belongs to family of Virgaviridae, and the genus Pomovirus. The virus was first identified in 1966 by Calvert and Harrison in Britain, and is now reported in many other potato cultivating regions of the world including U.S.A., Canada, China, Pakistan, Japan, South American countries and many parts of Europe. Many disease management systems have been found to be ineffective against the virus, although a combination of sanitation and vector controls seems to work well.
Wheat streak mosaic virus (WSMV) is a plant pathogenic virus of the family Potyviridae that infects plants in the family Poaceae, especially wheat ; it is globally distributed and vectored by the wheat curl mite, particularly in regions where wheat is widely grown. First described in Nebraska in 1922, stunted growth and the eponymous “streaks” of yellowed, non-uniform discoloration are characteristic of WSMV infection. As it has been known to cause 100% crop mortality, WSMV is a subject of ongoing scientific research.
Soil-borne wheat mosaic virus is a rod-shaped plant pathogen that can cause severe stunting and mosaic in susceptible wheat, barley and rye cultivars. The disease has often been misdiagnosed as a nutritional problem, but this has actually allowed in part for the fortuitous visual selection by breeding programs of resistant genotypes. Soil-borne wheat mosaic virus is part of the genus Furovirus. Members of this genus are characterized by rigid rod-shaped particles and positive sense RNA genomes consisting of two molecules that are packaged into separate particles that code for either replication, mobility, structure or defense against the host. The virus is spread by a fungal-like protist, Polymyxa graminis, whose asexual secondary and sexual primary cycles help the virus spread. The disease produces secondary symptoms from the root cell infection. The disease is a serious contributor to loss in crop yield.
Turnip crinkle virus (TCV) is a plant pathogenic virus of the family Tombusviridae. It was first isolated from turnip.
High plains disease is a viral disease afflicting wheat and maize. It is caused by the negative-sense ssRNA virus High Plains wheat mosaic emaravirus. Symptoms are similar to Wheat streak mosaic virus, with leaf veins showing yellow flecks and streaks, followed by leaf margin purpling in maize. Depending on the timing of infection, stunting and death occur. Plants can be doubly infected with high plains virus and wheat streak mosaic virus.
High Plains wheat mosaic emaravirus (WMoV), or High Plains virus (HPV) or Maize red stripe virus (MRSV/MRStV) is the causative agent of High plains disease of maize and wheat. It is spread by wheat curl mite, Aceria tosichella, which also transmits Wheat streak mosaic virus. The mite's ability to transmit a number of different viruses to cereal crops make it an economically important agricultural pest. In late June 2017 this virus was first detected in Canada, in Alberta. The Alberta samples were 99% similar to those in the USA. As Wheat streak mosaic virus is already present in Alberta, and coinfection with these two causes even more severe damage, this could cause much higher yield losses.
Positive-strand RNA viruses are a group of related viruses that have positive-sense, single-stranded genomes made of ribonucleic acid. The positive-sense genome can act as messenger RNA (mRNA) and can be directly translated into viral proteins by the host cell's ribosomes. Positive-strand RNA viruses encode an RNA-dependent RNA polymerase (RdRp) which is used during replication of the genome to synthesize a negative-sense antigenome that is then used as a template to create a new positive-sense viral genome.
Middelburg virus (MIDV) is an alphavirus of the Old World Group that has likely endemic and zoonotic potential. It is of the viral family Togaviridae. It was isolated from mosquitos in 1957 in South Africa, MDIV antigens have now been found in livestock, horses, and humans.
Rio Negro virus is an alphavirus that was first isolated in Argentina in 1980. The virus was first called Ag80-663 but was renamed to Rio Negro virus in 2005. It is a former member of the Venezuelan equine encephalitis complex (VEEC), which are a group of alphaviruses in the Americas that have the potential to emerge and cause disease. Río Negro virus was recently reclassified as a distinct species. Closely related viruses include Mucambo virus and Everglades virus.
