Flexiviridae
Encyclopedia
The Flexiviridae were a new family of virus
es in the 2004 classification of viruses, but have since the 2009 classification been split into the three new families Alphaflexiviridae
, Betaflexiviridae
and Gammaflexiviridae
. These have in turn been subsumed under the new order
Tymovirales
along with the old family Tymoviridae
by the International Committee on Taxonomy of Viruses
based on molecular phylogenetic systematic analyses
of proteins (RNA polymerase
and viral coat
). The viruses are positive-sense ssRNA viruses
, placing them in Group IV of the Baltimore classification
. These viruses are filamentous and named for being highly flexible.
Members of these families are readily transmitted mechanically and have other vectors of transmission. Species tend to be confined to a single host plant, many species preferring woody
hosts, but a diversity of angiosperm hosts are known to the Flexiviridae. Viral aggregates are known to form in the cytoplasm
of plant cell
s.
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es in the 2004 classification of viruses, but have since the 2009 classification been split into the three new families Alphaflexiviridae
Alphaflexiviridae
Alphaflexiviridae are single-stranded positive sense RNA plant viruses, belonging to the order Tymovirales and thus to group IV of the Baltimore classification of viruses.The Alphaflexiviridae family include the following genera:...
, Betaflexiviridae
Betaflexiviridae
Betaflexiviridae are single-stranded positive sense RNA plant viruses, belonging to the order Tymovirales and thus to group IV of the Baltimore classification of viruses.-Taxonomy:The Betaflexiviridae family include the following genera:...
and Gammaflexiviridae
Gammaflexiviridae
Gammaflexiviridae are single-stranded positive sense RNA plant viruses, belonging to the order Tymovirales and thus to group IV of the Baltimore classification of viruses.The Gammaflexiviridae family include the following genera:...
. These have in turn been subsumed under the new order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Tymovirales
Tymovirales
The Tymovirales are a newly established order of viruses in the 2009 classification with four genera.This group consists of viruses which have sense single stranded RNA genomes without DNA intermediates.-External links:*ICTV Virus Taxonomy 2009...
along with the old family Tymoviridae
Tymoviridae
Tymoviridae are monopartite single-stranded positive sense RNA plant viruses, belonging to group IV of the Baltimore classification of viruses...
by the International Committee on Taxonomy of Viruses
International Committee on Taxonomy of Viruses
The International Committee on Taxonomy of Viruses is a committee which authorizes and organizes the taxonomic classification of viruses. They have developed a universal taxonomic scheme for viruses and aim to describe all the viruses of living organisms. Members of the committee are considered to...
based on molecular phylogenetic systematic analyses
Molecular phylogeny
Molecular phylogenetics is the analysis of hereditary molecular differences, mainly in DNA sequences, to gain information on an organism's evolutionary relationships. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree...
of proteins (RNA polymerase
RNA polymerase
RNA polymerase is an enzyme that produces RNA. In cells, RNAP is needed for constructing RNA chains from DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses...
and viral coat
Capsid
A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...
). The viruses are positive-sense ssRNA viruses
RNA virus
An RNA virus is a virus that has RNA as its genetic material. This nucleic acid is usually single-stranded RNA but may be double-stranded RNA...
, placing them in Group IV of the Baltimore classification
Baltimore classification
The Baltimore classification, developed by David Baltimore, is a virus classification system that groups viruses into families, depending on their type of genome and their method of replication....
. These viruses are filamentous and named for being highly flexible.
Members of these families are readily transmitted mechanically and have other vectors of transmission. Species tend to be confined to a single host plant, many species preferring woody
Woody plant
A woody plant is a plant that uses wood as its structural tissue. These are typically perennial plants whose stems and larger roots are reinforced with wood produced adjacent to the vascular tissues. The main stem, larger branches, and roots of these plants are usually covered by a layer of...
hosts, but a diversity of angiosperm hosts are known to the Flexiviridae. Viral aggregates are known to form in the cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...
of plant cell
Plant cell
Plant cells are eukaryotic cells that differ in several key respects from the cells of other eukaryotic organisms. Their distinctive features include:...
s.