Characterization of Bean Necrotic Mosaic Virus: A Member of a Novel Evolutionary Lineage within the Genus Tospovirus

Abstract

BackgroundTospoviruses (Genus Tospovirus, Family Bunyaviridae) are phytopathogens responsible for significant worldwide crop losses. They have a tripartite negative and ambisense RNA genome segments, termed S (Small), M (Medium) and L (Large) RNA. The vector-transmission is mediated by thrips in a circulative-propagative manner. For new tospovirus species acceptance, several analyses are needed, e.g., the determination of the viral protein sequences for enlightenment of their evolutionary history.Methodology/Principal FindingsBiological (host range and symptomatology), serological, and molecular (S and M RNA sequencing and evolutionary studies) experiments were performed to characterize and differentiate a new tospovirus species, Bean necrotic mosaic virus (BeNMV), which naturally infects common beans in Brazil. Based upon the results, BeNMV can be classified as a novel species and, together with Soybean vein necrosis-associated virus (SVNaV), they represent members of a new evolutionary lineage within the genus Tospovirus.Conclusion/SignificancesTaken together, these evidences suggest that two divergent lineages of tospoviruses are circulating in the American continent and, based on the main clades diversity (American and Eurasian lineages), new tospovirus species related to the BeNMV-SVNaV clade remain to be discovered. This possible greater diversity of tospoviruses may be reflected in a higher number of crops as natural hosts, increasing the economic impact on agriculture. This idea also is supported since BeNMV and SVNaV were discovered naturally infecting atypical hosts (common bean and soybean, respectively), indicating, in this case, a preference for leguminous species. Further studies, for instance a survey focusing on crops, specifically of leguminous plants, may reveal a greater tospovirus diversity not only in the Americas (where both viruses were reported), but throughout the world.

Tospovirus ambisense genomic RNA segments use almost complete repertoire of stable tetraloops in the intergenic region

“…S1) show that all viruses of the Eurasian and the BeNMV/ SVNaV clades (Chen et al, 2013;de Oliveira et al, 2012) can also form an alternative extended rod-like structure competing with branched structures with two or three hairpins. Apparently, both alternatives and/or equilibrium between them are functional because they are stable thermodynamically, with rather close free energy values, and are supported by covariations ( Supplementary Fig.…”

Development of polyclonal antibodies against nucleocapsid protein of watermelon silver mottle virus and their application to diagnostic

“…Based on serological relationship of NPs, current classification of tospoviruses consists of three related serogroups including iris yellow spot virus, tomato spotted wilt virus and watermelon silver mottle virus (WSMoV) and four distinct serotypes including impatiens necrotic spot virus, panut yellow spot virus, peanut chlorotic fan-spot virus, and melon yellow spot virus (Yeh and Chang, 1995;Chu et al, 2001;Lin et al, 2005;Pappu et al, 2009;Chen et al, 2010;Seepiban et al, 2011). In addition, several new tospovirus species, such as alstroemeria necrotic streak virus, tomato necrotic ringspot virus, soybean vein necrosis-associated virus, bean necrotic mosaic virus, and hippeastrum chlorotic ringspot virus (HCRV) have been identified recently (Hassani-Mehraban et al, 2010;Seepiban et al, 2011;Zhou et al, 2011;de Oliveira et al, 2012;Dong et al, 2013).…”

First record of Tomato chlorotic spot virus in the USA

“…The diversity of the genus comprises 11 recognized species with a variable host range and geographic distribution, with an additional 15 proposed species (de Oliveira et al, 2012;Hassani-Mehraban et al, 2010;King et al, 2012). Species classification is based on serology, host range and nucleotide and predicted amino acid sequence of the N protein, which is located on the S RNA segment.…”

“…Species classification is based on serology, host range and nucleotide and predicted amino acid sequence of the N protein, which is located on the S RNA segment. Based in these criteria, tospoviruses have also been differentiated into American and Asiatic clades (de Oliveira et al, 2012;Hassani-Mehraban et al, 2010).…”