Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2017
Publication Date: 9/8/2017
Citation: Thekke-Veetil, T., McCoppin, N.K., Domier, L.L. 2017. Strain-specific association of soybean dwarf virus small subgenomic RNA with virus particles. Virus Research. 242:100-105.
Interpretive Summary: Soybean dwarf virus (SbDV) is a soybean-infecting virus that is spread from plant to plant only by the feeding of aphids. The virus is endemic in red clover in North America and transmitted by the recently introduced Asian soybean aphids that now regularly infest soybean fields in the northern half of the United States. While SbDV causes a severe disease of soybean in northern Japan, the virus has not developed into a problem in the United States. However, the periodic epizootics of Asian soybean aphids provide a potential route for infecting large numbers of soybean plants with SbDV within the core soybean producing region of the upper Midwest. To study how SbDV particles, which encase and protect the SbDV RNA chromosome in a protein shell, are assembled and transmitted by aphids, a system was developed to inoculate plants with cloned copies of the genomes of two SbDV isolates. The clones of both SbDV isolates were infectious in multiple plant species and one of the clones spread throughout inoculated tobacco plants, while the other was limited to inoculated leaves. The information presented in this manuscript will be of interest to scientists working to understand virus determinants of systemic virus movement in plants and transmission by aphids.
Technical Abstract: To develop a reverse genetics system for Soybean dwarf virus (SbDV), which is obligately transmitted by aphids, full-length cDNAs of red clover and soybean isolates of SbDV were cloned, and introduced into Nicotiana benthamiana plants by agroinfiltration and agroinjection. Clones of both SbDV isolates replicated, accumulated genomic and subgenomic RNAs, and produced SbDV virions that were detected by sucrose gradient centrifugation. Systemic infections were observed only when the veins, petioles, and stems of N. benthamiana plants were injected with agrobacterium suspensions harboring the clover SbDV clone. The complete genome sequences of both infectious clones were determined and compared.