An insight into the tomato spotted wilt virus (TSWV), tomato and thrips interaction

The genus Tospovirus is unique within the family Bunyaviridae in that it is made up of viruses that infect plants. Initially documented over 100 years ago, tospoviruses have become increasingly important worldwide since the 1980s due to the spread of the important insect vector Frankliniella occidentalis and the discovery of new viruses. As a result, tospoviruses are now recognized globally as emerging agricultural diseases. Tospoviruses and their vectors, thrips species in the order Thysanoptera, represent a major problem for agricultural and ornamental crops that must be managed to avoid devastating losses. In recent years, the number of recognized species in the genus has increased rapidly, and our knowledge of the molecular interactions of tospoviruses with their host plants and vectors has expanded. In this review, we present an overview of the genus Tospovirus with particular emphasis on new understandings of the molecular plant-virus and vector-virus interactions as well as relationships among genus members. Show more

During the past three decades, the economic impact of tospoviruses has increased, causing high yield losses in a variety of crops and ornamentals. Owing to the difficulty in combating thrips vectors with insecticides, the best way to limit/prevent tospovirus-induced diseases involves a management strategy that includes virus resistance. This review briefly presents current tospovirus taxonomy, diversity, molecular biology, and cytopathology as an introduction to a more extensive description of the two main resistance genes employed against tospoviruses: the Sw5 gene in tomato and the Tsw in pepper. Natural and experimental resistance-breaking (RB) isolates allowed the identification of the viral avirulence protein triggering each of the two resistance gene products; epidemiology of RB isolates is discussed to reinforce the need for allelic variants and the need to search for new/alternative resistance genes. Ongoing efforts for alternative resistance strategies are described not only for Tomato spotted wilt virus (TSWV) in pepper and tomato but also for other vegetable crops heavily impacted by tospoviruses. Show more

The complete nucleotide sequence of the S RNA of tomato spotted wilt virus (TSWV) was determined. The RNA is 2916 nucleotides long and has an ambisense coding strategy. The sequence contains two open reading frames (ORFs), one in the viral sense which encodes a protein with a predicted Mr of 52.4K and one in the viral complementary sense which encodes the viral nucleocapsid protein of Mr 28.8K. Both proteins are expressed by translation of two subgenomic RNA species that possibly terminate at a long stable hairpin structure, located at the intergenic region. The structure of this RNA segment resembles that of the arthropod-borne phleboviruses (family Bunyaviridae). The absence of significant sequence homology between TSWV and bunyaviruses infecting animals suggests that TSWV should be considered as a representative of a new genus within the Bunyaviridae. Show more