Tospovirus
A Viral Biorealm page on the family Tospovirus
Baltimore Classification
Group V (negative sense ssRNA)
Higher order categories
Bunyaviridae
Species
Tomato spotted wilt virus (TSWV); Impatiens necrotic spot virus (INSV); Watermelon silver mottle virus (WSMoV)
Description and Significance
Tospoviruses are enveloped viruses that infect plants. Any extremely wide variety of plants are susceptible to tospoviruses, including tomatoes, watermelon, peanuts, groundnuts, and flowers such as irises, impatiens, lilies, and orchids.
Genome Structure
The tospovirus genome consists of three ssRNA molecules. The molecules are simply known as L (Large), M (Medium), and S (Small). The entire genome codes for six proteins via five different open reading frames (ORFs). The L RNA encodes the virus' RNA-dependent RNA polymerase in its complement. The M RNA encodes two envelope precursor glycoproteins (G1 & G2) and a viral movement protein (NSm). The S RNA encodes the nucleoprotein (N) and a non-structural protein (NSs). The M and S RNAs are special, in that both are ambisense, meaning that one gene is encoded in the negative sense and another gene is encoded in the positive sense (Cortez et.al., 2001). The RNA molecules are capable of forming pseudo-circular panhandle structures, as well as stable hairpins, due to the presence of complementary terminal sequences (Dong et.al., 2008).
Virion Structure of a Tospovirus
The tospovirus virion consists of a quasi-spherical particle 80-120 nm in diameter containing the ssRNA genome. The paritcle is enclosed in an envelope (Cortez et.al., 2001).
Reproductive Cycle of a Tospovirus in a Host Cell
Viral Ecology & Pathology
Tospoviruses are frequently associated with insect vectors, specifically thrips. Thrips acquire the virus as larvae and transmit the virus as adults (Jones, 2005). Upon infection, the virus induces tissue necrosis.
References
Cortez, I., J. Saaijer, K.S. Wongjkaew, A.M. Pereira, R. Goldbach, D. Peters, & R. Kormelink. "Identification and characterization of a novel tospovirus species using a new RT-PCR approach." Archives of Virology 146 (2001): 265-278.
Dong,
Jones, D.R. "Plant viruses transmitted by thrips." European Journal of Plant Pathology 113 (2005): 119-157.
Page authored for BIOL 375 Virology, September 2008
