Tomato spotted wilt virus—positive steps towards negative success

Abstract

Taxonomy: Tomato spotted wilt virus (TSWV) is the type member of the plant-infecting Tospovirus genus in the family Bunyaviridae, a large group of predominantly vertebrate- and insect-infecting RNA viruses. Physical properties: Virions are 80-120-nm pleomorphic particles with surface projections composed of two viral glycoproteins, G1 and G2 (Fig. 1). Virion composition is 5% nucleic acid, 70% protein, 5% carbohydrate and 20% lipid. The genome consists of three negative or ambisense ssRNAs designated S (2.9 kb), M (4.8 kb) and L (8.9 kb), with partially complementary terminal sequences that allow the RNA to adopt a pseudocircular or panhandle conformation. Each genomic RNA is encapsidated by multiple copies of the viral nucleocapsid (N) protein to form ribonucleoprotein structures also known as nucleocapsids. The nucleocapsids are enclosed in a host-derived membrane bilayer along with an estimated 10-20 copies of the L protein, the putative RNA-dependent RNA polymerase. Hosts: Over 800 plant species, both dicots and monocots, in more than 80 plant families are susceptible to TSWV (Goldbach and Peters, 1994). The Solanaceae and Compositae families contain the largest numbers of susceptible plant species (Prins and Kormelink, 1998). TSWV also replicates in its insect vector, thrips (Thysanoptera: Thripidae) (Ullman et al., 1993; Wijkamp et al., 1993). Useful web site: http://www4.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/11050003.htm.

Phylogenetic analysis of Tomato spotted wilt virus (TSWV) NSs protein demonstrates the isolated emergence of resistance-breaking strains in pepper

“…M RNA encodes the precursor of two glycoproteins (Gn and Gc) that incorporate in the outer envelope/membrane of host-origin and a non-structural protein NSm playing role in the virus movement. From the S RNA, two proteins are translated: the nucleocapsid (N) and a nonstructural protein (NSs) [14]. According to de Ronde et al [15], NSs is the suppressor protein of the host plant gene silencing mechanism and it is responsible for breakdown of the plant's resistance (avirulence factor, avr).…”

Evolutionary analysis of tomato Sw-5 resistance-breaking isolates of Tomato spotted wilt virus

“…Phylogenetic analysis revealed that substitution C118Y has occurred independently three times in the studied isolates by convergent evolution, whereas the substitution T120N was a unique event. Analysis of rates of non-synonymous and synonymous changes at individual codons showed that substitution C118Y was positively selected.Tomato spotted wilt virus (TSWV) is one of the most economically important plant viruses and causes damage in many agronomic crops worldwide (Adkins, 2000). TSWV is the type member of the genus Tospovirus, which contains the only plant-infecting members of the family Bunyaviridae.…”

“…Tomato spotted wilt virus (TSWV) is one of the most economically important plant viruses and causes damage in many agronomic crops worldwide (Adkins, 2000). TSWV is the type member of the genus Tospovirus, which contains the only plant-infecting members of the family Bunyaviridae.…”

Expression, purification, crystallization and preliminary X-ray crystallographic study of the nucleocapsid protein ofTomato spotted wilt virus

“…The S RNA segment encodes the nucleocapsid (N) and NSs proteins, the M RNA segment encodes glycoproteins (Gn and Gc) and NSm proteins, and the L RNA segment encodes the RNA-dependent RNA polymerase (RdRp) (Adkins, 2000). The numerous N proteins encapsidate viral genome RNAs and, in association with a few RdRps, constitute vRNP (viral ribonucleoprotein) complexes (Uhrig et al, 1999;Richmond et al, 1998).…”