An RNA virus is a virus that has RNA as its genetic material. This nucleic acid is usually single-stranded RNA (ssRNA) but may be double-stranded RNA (dsRNA). Notable human diseases caused by RNA viruses include the common cold, influenza, SARS, MERS, COVID-19, Dengue Virus, hepatitis C, hepatitis E, West Nile fever, Ebola virus disease, rabies, polio, mumps, and measles.
Virusoids are circular single-stranded RNA(s) dependent on viruses for replication and encapsidation. The genome of virusoids consist of several hundred (200–400) nucleotides and does not code for any proteins.
Flavivirus is a genus of positive-strand RNA viruses in the family Flaviviridae. The genus includes the West Nile virus, dengue virus, tick-borne encephalitis virus, yellow fever virus, Zika virus and several other viruses which may cause encephalitis, as well as insect-specific flaviviruses (ISFs) such as cell fusing agent virus (CFAV), Palm Creek virus (PCV), and Parramatta River virus (PaRV). While dual-host flaviviruses can infect vertebrates as well as arthropods, insect-specific flaviviruses are restricted to their competent arthropods.
Rubella virus (RuV) is the pathogenic agent of the disease rubella, and is the main cause of congenital rubella syndrome when infection occurs during the first weeks of pregnancy.
Nodaviridae is a family of nonenveloped positive-strand RNA viruses. Vertebrates and invertebrates serve as natural hosts. Diseases associated with this family include: viral encephalopathy and retinopathy in fish.There are nine species in the family divided among two genera.
The Pospiviroidae are a family of viroids, including the first viroid to be discovered, PSTVd. Their secondary structure is key to their biological activity. The classification of this family is based on differences in the conserved central region sequence. The genome consists of an LH terminal domain, a pathogenic domain, conserved central region, variable domain, and an RH terminal domain. Pospiviroidae replication occurs in an asymmetric fashion via host cell RNA polymerase, RNase, and RNA ligase.
Potyvirus is a genus of viruses in the family Potyviridae. Plants serve as natural hosts. There are currently 183 species in this genus including the type species Potato virus Y. The genus is named after the type virus. Potyviruses account for ~30% 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.
Begomovirus is a genus of viruses, in the family Geminiviridae. They are plant viruses that as a group have a very wide host range, infecting dicotyledonous plants. Worldwide they are responsible for a considerable amount of economic damage to many important crops such as tomatoes, beans, squash, cassava and cotton. There are currently 424 species in this genus including the type species Bean golden yellow mosaic virus.
Closterovirus, also known as beet yellows viral group, is a genus of viruses, in the family Closteroviridae. Plants serve as natural hosts. There are currently 16 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.
Crinivirus, formerly the lettuce infectious yellows virus group, is a genus of viruses, in the family Closteroviridae. They are linear, single-stranded positive sense RNA viruses. There are currently 14 species in this genus including the type species Lettuce infectious yellows virus. Diseases associated with this genus include: yellowing and necrosis, particularly affecting the phloem.
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 Bromoviridae family. 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.
Strawberry crinkle cytorhabdovirus, commonly called Strawberry crinkle virus (SCV), is a negative sense single stranded RNA virus that threatens strawberry production worldwide. This virus reduces plant rigidity, runner production, fruit size, and production, while causing distortion and crinkling of the leaves. This virus was first described in 1932 in Oregon and California with commercial strawberry varieties, and later became an issue around the world, including North America, South America, Europe, South Africa, New Zealand, Australia, and Japan. Of the family Rhabdoviridae, it is a large family of viruses that affects plants, vertebrates, and invertebrates. Specifically, this virus is transmitted through two aphid vectors that feed on strawberry plants of genus Fragaria, Chaetosiphon fragaefolii and C. jacobi. When SCV is combined with other aphid-transmitted strawberry viruses, such as mottle, mild yellow-edge, vein banding, or pallidosis, the damage becomes even more deleterious. Economically, Fragaria ananassa are those being affected by SCV.
Carlavirus, formerly known as the "Carnation latent virus group", is a genus of viruses in the order Tymovirales, in the family Betaflexiviridae. Plants serve as natural hosts. There are currently 53 species in this genus including the type species Carnation latent virus. Diseases associated with this genus include: mosaic and ringspot symptoms.
Secoviridae is a family of viruses in the order Picornavirales. Plants serve as natural hosts. There are currently 86 species in this family, divided among 8 genera or not assigned to a genus. The family was created in 2009 with the grouping of families Sequiviridae, now dissolved, and Comoviridae, now subfamily Comovirinae, along with the then unassigned genera Cheravirus, Sadwavirus, and Torradovirus.
Alphasatellites are single stranded satellite DNA that are dependent on a virus for transmission. 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.
Ipomovirus is a genus of viruses, in the family Potyviridae. There are currently seven species in this genus including the type species Sweet potato mild mottle virus. They infect plants and are transmitted by whiteflies. The name of the genus is derived from Ipomoea - the generic name of sweet potato.
Badnavirus is a genus of viruses, in the family Caulimoviridae order Ortervirales. Plants serve as natural hosts. There are currently 59 species in this genus including the type species Commelina yellow mottle virus. 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.
Polerovirus is a genus of viruses, in the family Luteoviridae. Plants serve as natural hosts. There are currently 26 species in this genus including the type species Potato leafroll virus. 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 currently 28 species in this genus including the type species Turnip yellow mosaic virus.
The Blueberry mosaic associated ophiovirus (B1MaV) is a plant virus which infects blueberry plants, causing a discoloration of the leaves of the plants in a mosaic-like pattern. The disease is found in blueberry plants in many regions of North America, as well as South America, Europe, New Zealand, and South Africa. Within these regions the virus is most often found in high blueberry-yielding areas, but can be spread to other locations. Blueberry mosaic associatedophiovirus is one of seven species in the genus Ophiovirus. It is a member of the Aspiviridae family, in the Serpentovirales order, and in the Milnevircetes class. The Ophioviridae viruses are characterized by a flexible and elongated nucleocapsid that is composed mostly of filamentous structures and is helically symmetrical. It also has a non-enveloped protein capsid that is capable of coiling around itself allowing for a super-coiled structure and the helical symmetry. The virus has the potential to be symptomatic or asymptomatic within plants causing the display of symptoms in only a few plants, but the ability to transmit the virus unknowingly in many plants. B1MaV often remains asymptomatic for long periods of time after initial infection allowing for blind transmission.
