Generation of polyclonal antibodies and serological analyses of nucleocapsid protein of Soybean vein necrosis-associated virus: A distinct soybean infecting tospovirus serotype

Soybean vein necrosis-associated virus (SVNaV) is a newly isolated tospovirus from field-grown soybeans in the United States. Polyclonal antibodies generated against the recombinant Escherichia coli-expressed nucleocapsid protein (NP) of the virus, reacted specifically with SVNaV and exhibited low, if any, cross-reactivity with other species within the genus Tospovirus. The serological results are in agreement with low sequence homology of the SVNaV-NP gene when compared with those of other tospovirus species, some of which are capable of infecting soybean naturally. Phylogenetic analysis utilizing NP sequences from several SVNaV isolates collected from different geographical regions and various soybean genotypes over 4 years showed close relationships, but distinct from the representatives of all the established serogroups or distinct serotypes within the genus of Tospovirus. All SVNaV isolates examined reacted strongly with the generated polyclonal antibodies. Collectively, our serological analyses suggest that SVNaV represents a new and distinct soybean-infecting tospovirus serotype. Furthermore, our data demonstrate that antiserum against NP has the potential to serve as a reliable probe for SVNaV detection in field-grown soybeans.