Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/2007
Publication Date: 12/30/2007
Citation: Thekkeveetil, T., Hobbs, H.A., Wang, Y., Kridelbaugh, D., Donnelly, J., Hartman, G.L., Domier, L.L. 2007. First report of Soybean dwarf virus in soybean in Northern Illinois. Plant Disease. 91(12):1686. Interpretive Summary: Soybean dwarf virus (SbDV) causes widespread economic losses on soybean in Japan. Even though SbDV is common in clovers growing next to soybean fields in the US, SbDV rarely infects soybean plants in the US. The inability of the SbDV to move from clovers to soybeans has been attributed to the absence of aphid vectors that colonize soybeans and have the ability to transmit the virus. In 2000, the Asian soybean aphid, which colonizes soybean plants and transmits SbDV was discovered in North America for the first time. In 2006, soybean fields and sentinel plots for Asian soybean rust were surveyed for SbDV. SbDV was detected in both soybean production fields and sentinel plots at an incidence of about 0.3%. The viruses detected in Illinois were closely related to SbDVs from Japan that cause severe dwarfing of soybean plants. The importance of the Asian soybean aphid in the epidemiology of SbDV remains to be determined. The information in this paper should be useful to other scientists who are studying the epidemiology and distribution of SbDV.
Technical Abstract: Soybean dwarf virus (SbDV) is transmitted persistently by colonizing aphids and causes significant yield losses in soybean in Japan. In the United States, SbDV is endemic in red and white clover, but has been detected in soybean only in Virginia and Wisconsin. During August 2006, two surveys for virus diseases in soybean were conducted in Illinois. In the first, 30 soybean leaf samples were collected without regard for symptoms from each of 10 fields in each of five northern Illinois counties. In the second survey, 20 soybean leaf samples were collected from each of 30 soybean rust sentinel plots spread throughout Illinois. Total RNA was extracted from pools of 90-100 plants and analyzed by quantitative real-time reverse transcriptase polymerase chain reaction. From the first survey, pools from three counties were positive for SbDV. Analysis of individual leaf samples from positive pools showed that one sample in each county was positive for SbDV, which indicated that about 0.3% of sampled plants were infected with SbDV. In the second survey, SbDV was detected in one sentinel plot. Sequence analysis of the combined coat protein and read through domain encoding regions of Illinois SbDV isolates showed that their predicted amino acid sequences were greater than 95% identical to a Japanese dwarfing isolate of SbDV. This is the first report of infection of soybean plants in Illinois with SbDV.