''Iflaviridae'' is a family of positive sense RNA viruses

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pa ...

-infecting

virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsk ...

es. Some of the insects commonly infected by iflaviruses include

aphid Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...

leafhopper A leafhopper is the common name for any species from the family Cicadellidae. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and ...

flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced m ...

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamil ...

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of ...

silkworm The domestic silk moth (''Bombyx mori''), is an insect from the moth family Bombycidae. It is the closest relative of '' Bombyx mandarina'', the wild silk moth. The silkworm is the larva or caterpillar of a silk moth. It is an economically ...

s and

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder ...

s. The name "Ifla" is derived from the name "Infectious flacherie virus", a member species. There is one genus (''Iflavirus'') and 16 species in this family.

Structure

Members of this family are insect-infecting viruses that consist of positive single-strand RNA genomes translated into a single polyprotein of ~3000 amino acids long. It encodes

helicase Helicases are a class of enzymes thought to be vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separatin ...

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ...

and

RNA-dependent RNA polymerase RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to ...

enzymes and four structural proteins (VP1–4). The

non-enveloped A viral envelope is the outermost layer of many types of viruses. It protects the genetic material in their life cycle when traveling between host cells. Not all viruses have envelopes. Numerous human pathogenic viruses in circulation are encas ...

capsid A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or ma ...

has an icosahedral T=pseudo3 symmetry and is around 30 nm in diameter. VP1, VP2 and VP3 form the outer portion, with VP4 located internally. Genomes are linear and non-segmented, around 8.8-9.7kb in length.

Life cycle

Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment to host receptors, which mediates endocytosis. Replication follows the positive stranded RNA virus replication model. Positive stranded RNA virus transcription is the method of transcription. Translation takes place by ribosomal skipping. Insects serve as the natural host.

Pathogenicity

Several viruses in this family are economically important because they are highly pathogenic to their honeybee and silkworm hosts, while others (including ''Dinocampus coccinellae paralysis virus'', ''Nasonia vitripennis virus'' and ''Venturia canescens picorna-like virus'') appear to cause little or no symptoms.

Taxonomy

The family ''Iflaviridae'' contains one genus, ''Iflavirus'', with the following 16 species: *''

Acheta domesticus iflavirus ''Acheta'' is a genus of crickets. It most notably contains the house cricket (''Acheta domesticus''). According to Direction 46 issued by the ICZN in 1956, this generic name is masculine in gender. Species *'' Acheta angustiusculus'' *'' Acheta ...

'' *''

Antheraea pernyi iflavirus ''Antheraea'' is a moth genus belonging to the family Saturniidae. The genus was erected by Jacob Hübner in 1819. Several species of this genus have caterpillars which produce wild silk of commercial importance. Commonly called "tussar silk", t ...

'' *''

Brevicoryne brassicae virus ''Brevicoryne'' is a genus of aphid insect that contains many species which are agricultural pests. Hosts This genus parasitizes a wide range of hosts, with many members of the Brassicaceae (broccoli, cabbage, kale, etc.) included. Adults Adu ...

'' *''

Deformed wing virus ''Deformed wing virus'' (DWV) is an RNA virus, one of 22 known viruses affecting honey bees. While most commonly infecting the honey bee, ''Apis mellifera'', it has also been documented in other bee species, like '' Bombus terrestris'', thus, i ...

'' *''

Dinocampus coccinellae paralysis virus ''Dinocampus coccinellae paralysis virus'' (DcPV) is a single-stranded, positive-sense RNA virus of insects, in the picorna-like virus family ''Iflaviridae'', which was first characterised in 2015. It asymptomatically infects the parasitic brac ...

'' *''

Ectropis obliqua virus ''Ectropis'' is a genus in the geometer moth family (Geometridae). They are mostly paleotropical, but also plentiful in Australia and extend into Asia. Only one species – or cryptic species complex – (the engrailed/small engrailed ...

'' *''

Infectious flacherie virus An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable d ...

'' *'' Lygus lineolaris virus 1'' *''

Lymantria dispar iflavirus 1 ''Lymantria'' is a genus of tussock moths in the family Erebidae. They are widely distributed throughout Europe, Japan, India, Sri Lanka, Myanmar, Java, and Celebes. The genus was erected by Jacob Hübner in 1819. Description In the male, the p ...

'' *''

Nilaparvata lugens honeydew virus 1 ''Nilaparvata''Distant WL (1906) ''The fauna of British India, including Ceylon and Burma.'' 3: 503 pp. 47 is a genus of planthoppers in the subfamily Delphacinae and tribe Delphacini Leach, 1815. Species are widely distributed in the Americas, ...

'' *''

Perina nuda virus ''Perina'' is a genus of tussock moths in the family Erebidae The Erebidae are a family of moths in the superfamily Noctuoidea. The family is among the largest families of moths by species count and contains a wide variety of well-known mac ...

'' *''

Sacbrood virus Sacbrood virus or SBV disease is an infectious disease caused by the ''Morator aetatulas'' virus that affects honey bee larvae. When sick, the colony declines gradually with few or no replacement workers, costing 20-80% of honey production. Rea ...

'' *''

Slow bee paralysis virus Slow bee paralysis virus (SBPV) is a virus discovered in England in 1974 that infects honeybees (''Apis mellifera''), bumblebees (''Bombis spp.)'', and silkworms (''Bombyx mori)'' through ''Varroa destructor'' mite infestations. The virus causes ...

'' *''

Spodoptera exigua iflavirus 1 ''Spodoptera'' is a genus of moths of the family Noctuidae erected by Achille Guenée in 1852. Many are known as pest insects. The larvae are sometimes called armyworms. The roughly thirty species are distributed across six continents. Descrip ...

'' *'' Spodoptera exigua iflavirus 2'' *''

Varroa destructor virus-1 ''Varroa'' is a genus of parasitic mesostigmatan mites associated with honey bees, placed in its own family, Varroidae. The genus was named for Marcus Terentius Varro, a Roman scholar and beekeeper. The condition of a honeybee colony being infe ...

References

External links

ICTV Online (10th) Report; Iflaviridae

ICTV Online (10th) Report; Iflaviridae, alternative link

{{Taxonbar, from=Q5991208 Picornavirales Virus families