Rice Dwarf Virus
Classification
Virus, dsRNA viruses, Reoviridae, Phytoreovirus, Rice Dwarf Virus
Species
Rice Dwarf Virus
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NCBI: Taxonomy |
Genus species Phytoreovirus Rice Dwarf Virus
Description and Significance
The Rice Dwarf Virus was the first studied plant viruses. It has since been used as a model teaching tool for understanding plant virus mechanisms. RDV uses an insect vector to infect rice and wheat plants. The virus is an isohedral double shelled virus, ranging from 70-75 nm in diameter. There are three strains of the RDV: O, D84, and S. Strain S is the most virulent and causes the most severe symptoms. Describe the appearance, habitat, etc. of the organism, and why you think it is important. [1,3]
Genome Structure
The Rice Dwarf Virus is a double-stranded linear RNA virus. The dsRNA consists of 12 segments. Each segment ranges from 4.4 kb pairs to 0.83 kb pairs. The total size of the genome is 25.13 kb pairs. The base composition of the genome is 42-48% C-G. Segments S1, S2, S3, S5, S7, and S8 are known to code for functional proteins. These proteins code for RNA Polyemerase, capsid structure, cell absorption, and nucleic acid binding. The genome of the RDV has been sequenced and is often used as a tool to understanding viral plant pathogens.
Cell Structure, Metabolism and Life Cycle
The RDV is an isohedral virus containing 32 capsomeres. The capsomeres are arranged in a conspicuous manner. The virons are isometeric and not enveloped. The virus has an angular profile. The RDV enters the host cell then begins replication and assembly. The viruses then participate in intracellular transport by taking over host mechanisms. Tubulars are created and extended outward to other host cells. This enables the RDV to move intracellularly into un-infected host cells and being replication.
Ecology and Pathogenesis
RDV is found in the rice paddies of China and Japan. The viruses participate in transovarial transmission through leafhopper insects. The insects become infected with the virus and can then eat other plants and infect them or reproduce and pass the virus onto its offspring. An infected rice plant often shows symptoms such as stunted growth, shortened internodes, chlorotic flecks at infection site, and inhibited root growth (only extend horizontally). There are often three steps to the eradication of a disease: prophylaxis, therapy, and immunization. Integrating pest control and management through chemicals has been the most effective.
References
http://pdf.usaid.gov/pdf_docs/pnaaa923.pdf Ling K. "Rice Virus Diseases." International Rice Research Institute. 1972 p. 55-62.
http://www.iita.org/c/document_library/get_file?uuid=91e91c5d-a854-4eba-80ae-c677236a0e9f&groupId=25357 Abo M, Fadhila H. "Epidemiology and Management of Rice Viruses and Virus Diseases."National Cereals Institute. 1991 p. 113-121.
http://pvo.bio-mirror.cn/descr686.htm Brunt A, Crabtree K, Dallwitz M, Gibbs A, Watson L, Zurcher E. "Plant Viruses Online: Descriptions and Lists from the VIDE Database." 1996.
http://jvi.asm.org/content/80/17/8593.full Wei T, Kikuchi A, Moriyasu Y, Suzuki N, Shimizu T, Hagiwara K, Chen H, Takahashi M, Ichiki-Uehara T, Omura T. "The Spread of Rice Dwarf Virus among Cells among its Insect Vector Exploits Virus-Induced Tubular Structures." Journal of Virology. 2006 vol 80.
Author
Page authored by Chelsea A. Wissel, student of Prof. Jay Lennon at IndianaUniversity.
