| Soybean vein necrosis disease (SVND) is widespread in major soybean-producing areas in the U.S. The typical disease symptoms exhibit as vein clearing along the main vein, which turn into chlorosis or necrosis as season progresses. Double-stranded RNA isolation and shot gun cloning of symptomatic tissues revealed the presence of a new tospovirus, provisionally named as Soybean vein necrosis associated virus (SVNaV). The presence of the virus has been confirmed in 12 states: Arkansas, Illinois, Missouri, Kansas, Tennessee, Kentucky, Mississippi, Maryland, Delaware, Virginia and New York. Symptomatic samples collected from eight states (AR, IL, MO, MS, KS, TN, MD and DE), were used to study the population structure of the virus. The study revealed a perfect correlation between SVND and the presence of SVNaV and a relatively homogeneous virus population indicating that the diverse symptoms observed in the field is probably caused by the different host genotypes rather than distinct virus strains. Virus epidemiology is critical for virus control and disease management. In this study, in total of 24 plant species belonging to ten families were tested by mechanical inoculation as potential alternative hosts of SVNaV and seven species belonging to five families can sustain virus replication. In order to efficiently detect SVNaV, detection protocols based on reverse transcription---PCR (RT-PCR) and quantitative RT-PCR (qRT-PCR) was developed and their sensitivity was compared with immunological test that is currently available. |
