Phytoreovirus
Encyclopedia
Phytoreoviruses are non-turreted reoviruses that are major agricultural pathogens, particularly in Asia
. One member of this family, Rice Dwarf Virus
(RDV), has been extensively studied by electron cryomicroscopy and x-ray crystallography
. From these analyses, atomic models of the capsid proteins and a plausible model for capsid assembly have been derived. While the structural protein
s of RDV share no sequence similarity to other proteins, their folds and the overall capsid
structure are similar to those of other Reoviridae
.
Phytoreoviruses are unique among Reoviridae in that there are 12 dsRNA segments in each virus. Like all other Reoviridae, they contain their own RNA-dependent RNA polymerase
, allowing for endogenous synthesis of viral mRNA within the virus. Although less well studied than orthoreovirus
and orbivirus
, considerable structural and biochemical studies have been undertaken to characterize phytoreoviruses, which in general infect plants. There are three recognized phytoreoviruses: wound tumour virus (WTV), rice dwarf virus
(RDV) and rice gall dwarf virus (RGDV). Possible additional family members include tobacco leaf enation virus (TLEF), rice bunchy stunt virus and sweet potato virus (ICTV, VIDE). There are also several RDV isolates, all of which share over 90% sequence identity. Of these phytoreoviruses, RDV has been extensively studied and is the best characterized member. Most of our knowledge about phytoreovirus assembly and structure is based on structural data accumulated in RDV studies.
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. One member of this family, Rice Dwarf Virus
Rice dwarf virus
Rice dwarf virus is a plant pathogenic virus of the family Reoviridae.-External links:**...
(RDV), has been extensively studied by electron cryomicroscopy and x-ray crystallography
X-ray crystallography
X-ray crystallography is a method of determining the arrangement of atoms within a crystal, in which a beam of X-rays strikes a crystal and causes the beam of light to spread into many specific directions. From the angles and intensities of these diffracted beams, a crystallographer can produce a...
. From these analyses, atomic models of the capsid proteins and a plausible model for capsid assembly have been derived. While the structural protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s of RDV share no sequence similarity to other proteins, their folds and the overall capsid
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...
structure are similar to those of other Reoviridae
Reoviridae
Reoviridae is a family of viruses that can affect the gastrointestinal system and respiratory tract. Viruses in the family Reoviridae have genomes consisting of segmented, double-stranded RNA...
.
Phytoreoviruses are unique among Reoviridae in that there are 12 dsRNA segments in each virus. Like all other Reoviridae, they contain their own RNA-dependent 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...
, allowing for endogenous synthesis of viral mRNA within the virus. Although less well studied than orthoreovirus
Orthoreovirus
Orthoreoviruses are members of the Reoviridae virus family. They have double stranded RNA genomes and are therefore group III viruses. These viruses infect vertebrates but no disease symptoms are normally seen. In some cases however, orthoreovirus infection can lead to complications, especially in...
and orbivirus
Orbivirus
The genus Orbivirus is a member of the Reoviridae family. This genus currently contains 22 species and at least 130 different serotypes. Orbiviruses can infect and replicate within a wide range of arthropod and vertebrate hosts...
, considerable structural and biochemical studies have been undertaken to characterize phytoreoviruses, which in general infect plants. There are three recognized phytoreoviruses: wound tumour virus (WTV), rice dwarf virus
Rice dwarf virus
Rice dwarf virus is a plant pathogenic virus of the family Reoviridae.-External links:**...
(RDV) and rice gall dwarf virus (RGDV). Possible additional family members include tobacco leaf enation virus (TLEF), rice bunchy stunt virus and sweet potato virus (ICTV, VIDE). There are also several RDV isolates, all of which share over 90% sequence identity. Of these phytoreoviruses, RDV has been extensively studied and is the best characterized member. Most of our knowledge about phytoreovirus assembly and structure is based on structural data accumulated in RDV studies.
See also
- MicrobiologyMicrobiologyMicrobiology is the study of microorganisms, which are defined as any microscopic organism that comprises either a single cell , cell clusters or no cell at all . This includes eukaryotes, such as fungi and protists, and prokaryotes...
- VirologyVirologyVirology is the study of viruses and virus-like agents: their structure, classification and evolution, their ways to infect and exploit cells for virus reproduction, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy...
- RNA virusRNA virusAn 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...
- List of viruses
- Animal virologyAnimal virologyThe study of animal viruses is important from a veterinary viewpoint and many of these viruses cause diseases that are economically devastating. Many animal viruses are also important from a human medical perspective...