Taxonomy

The genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Fijivirus is a member of the 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...

 virus

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...

 family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

. These have double-stranded RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

 genome

Genome

In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

s and are therefore group III viruses. These viruses infect plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s - unusual for reoviruses - and can also replicate in their arthropod

Arthropod

An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...

 intermediate host

Intermediate host

A secondary host or intermediate host is a host that harbors the parasite only for a short transition period, during which some developmental stage is completed. For trypanosomes, the cause of sleeping sickness, humans are the primary host, while the tsetse fly is the secondary host...

s.

Structure

Fijivirus genome composition contains ten linear double-stranded RNA (dsRNA) and is carried within virus particles referred to as virions. The Fijivirus genome is constructed inside the virion and is non-envelope

Envelope

An envelope is a common packaging item, usually made of thin flat material. It is designed to contain a flat object, such as a letter or card....

d. It contains two separate layers of capsids, an inner and an outer layer, which are constructed by proteins that shell the virus.The capsids are of icosahedral symmetry

Icosahedral symmetry

A regular icosahedron has 60 rotational symmetries, and a symmetry order of 120 including transformations that combine a reflection and a rotation...

, and have an obvious round structure, which is on average 65-70nm in diameter.

Replication

Replications of the Fijivirus occurs within 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...

; the virus will diffuse through the cytoplasm of the cell. Transcription

Transcription

Transcription may refer to:*Transcription , a business which converts speech into a written or electronic text document*Transcription , software which helps convert speech into text transcript...

 of the dsRNA genome occurs inside the virion, and this is important so that the dsRNA is not exposed to the cytoplasm. Transcription results in a positive strand that is then used as the template for translation

Translation

Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. Whereas interpreting undoubtedly antedates writing, translation began only after the appearance of written literature; there exist partial translations of the Sumerian Epic of...

. The positive RNAs become enclosed within the virion, and then are transcribed to give RNA molecules. With the newly formed molecule, it then becomes base-paired to produce the dsRNA genomes as described above. Mature virions are released following cell death and the breakdown of the affected hosts plasma membrane

Membrane

-In biology:* Biological membrane* Cell membrane, a biological type of Membrane ** Inner membrane** Outer membrane * The two fetal membranes** amnion** chorion* Basement membrane* Mucous membrane* Serous membrane...

. (Major source for information was retrieved from http://viralzone.expasy.org/all by species/612.html)

Host/Transmission

Host: Plants (Gramineae), and planthopper

Planthopper

A planthopper is any insect in the infraorder Fulgoromorpha within the Hemiptera. The name comes from their remarkable resemblance to leaves and other plants of their environment and from the fact that they often "hop" for quick transportation in a similar way to that of grasshoppers. However,...

s (vectors)

The virus is transmitted by planthoppers, which are insects, or other types of organisms that transmit the pathogen by bacteria, fungus, or virus. The virus will infect the phloem

Phloem

In vascular plants, phloem is the living tissue that carries organic nutrients , in particular, glucose, a sugar, to all parts of the plant where needed. In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Greek word "bark"...

 tissues of their Gramineae hosts. If the presence of a gall

Gall

Galls or cecidia are outgrowths on the surface of lifeforms caused by invasion by other lifeforms, such as parasites or bacterial infection. Plant galls are abnormal outgrowths of plant tissues and can be caused by various parasites, from fungi and bacteria, to insects and mites...

appears, usually located on specific parts of the plant, if can represent the first sign of the virus (Pearson 2004). A gall's replication can occur both in the host and the vector. The plant is unable to recover from the unexpected growth and therefore can become stunted, and can eventually die.

External links

• Viralzone: Fijivirus