''Amalgaviridae'' is a family of double-stranded

RNA virus An RNA virus is a virus characterized by a ribonucleic acid (RNA) based genome. The genome can be single-stranded RNA (ssRNA) or double-stranded (Double-stranded RNA, dsRNA). Notable human diseases caused by RNA viruses include influenza, SARS, ...

es. Member viruses infect

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

s and are transmitted vertically via

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s. The name derives from ''amalgam'' (blend, mix) which refers to amalgaviruses possessing characteristics of both partitiviruses and totiviruses. The family contains three genera.

Genome

Amalgavirus genomes are

monopartite Monopartite refers to the class of genome that is presented in the genome of the virus. As opposed to multipartite, viruses composed of monopartite genomes have a single molecule of nucleic acid. Most dsDNA Deoxyribonucleic acid (; DNA) i ...

and about 3.5

kilobase A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

s in length. They have two partially overlapping

open reading frame In molecular biology, reading frames are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible reading frames ...

s which encode the

RNA-dependent RNA polymerase RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the self-replication, replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand Complementarity (molecular biology), compleme ...

(RdRp) and a putative

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 m ...

protein.

Evolution

It has been suggested that amalgaviruses have evolved via recombination between viruses with double-stranded and negative-strand RNA genomes. Phylogenetic analysis indicates that the amalgavirus RdRp forms a sister clade to the corresponding RdRp protein of partitiviruses (''

Partitiviridae ''Partitiviridae'' is a family of double-stranded RNA viruses. Plants, fungi, and protozoa serve as natural hosts. It has been suggested that they can also infect bacteria. The name comes from the Latin ''partitius,'' which means divided, and ...

'') which have segmented (bipartite) dsRNA genomes and infect plants, fungi and protists. By contrast, the putative capsid protein of amalgaviruses is homologous to the nucleocapsid proteins of

negative-strand RNA virus Negative-strand RNA viruses (−ssRNA viruses) are a group of related viruses that have Sense (molecular biology), negative-sense, single-stranded genomes made of ribonucleic acid (RNA). They have genomes that act as complementary strands from w ...

es of the genera ''

Phlebovirus ''Phlebovirus'' is a genus of viruses in the family '' Phenuiviridae'' in the order '' Hareavirales''. The genus contains 67 species. It derives its name from Phlebotominae, the vectors of member species Sandfly fever Naples virus, which is sa ...

'' and ''

Tenuivirus ''Tenuivirus'' is a plant virus genus belonging to ''Phenuiviridae'' family in the order '' Hareavirales''. These plant viruses cause diseases in their host plants. Typical symptoms are chlorotic stripes on the affected leaves. This group of viru ...

''.

Taxonomy

The family contains the following genera: * '' Amalgavirus'' * '' Unirnavirus'' * '' Zybavirus''

References

{{Taxonbar, from=Q18810541 Double-stranded RNA viruses Riboviria Virus families