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Molecular Plant Pathology

Identification of dsRNAs Associated with Soybean Dwarf Virus-Infected Soybean. O. P. Smith, Research plant pathologists, USDA-ARS, Foreign Disease-Weed Science Research, Fort Detrick, Bldg. 1301, Frederick, MD 21702; P. L. Hunst(2), A. D. Hewings(3), A. L. Stone(4), S. A. Tolin(5), and V. D. Damsteegt(6). (2)(5)Research associate and professor, Dept. of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute & State University, Blacksburg 24061. (2)Present address: Endotech, Inc., 1497 Drew Ave., Davis, CA 95616; (3)(6)Research plant pathologists, USDA-ARS, Foreign Disease-Weed Science Research, Fort Detrick, Bldg. 1301, Frederick, MD 21702, (3)Present address: USDA-ARS, Crop Protection Research, N-519 Turner Hall, University of Illinois, 1102 South Goodwin Avenue, Urbana 61801; (4)Biological laboratory technician, USDA-ARS, Foreign Disease-Weed Science Research, Fort Detrick, Bldg. 1301, Frederick, MD 21702. Phytopathology 81:131-134. Accepted for publication 17 July 1990. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1991. DOI: 10.1094/Phyto-81-131.

Double-stranded (ds) RNA was isolated from leaves of soybean cultivar Wayne infected with the dwarfing (D) or yellowing (Y) strain of soybean dwarf virus (SDV). Each strain produced two virus-specific dsRNAs. SDV-D dsRNAs were estimated to have molecular weights of 3.4 and 1.9 × 10⁶ Da. The corresponding SDV-Y species were larger, having estimated molecular weights of 3.6 and 2.2 × 10⁶ Da. Northern blot hybridization analyses showed the strains are related and that the two dsRNAs correspond to viral genomic-length and 3’ subgenomic-length species. The detection of SDV dsRNA by polyacrylamide gel electrophoresis (dsRNA profiles) was improved by combining S₁ nuclease with DNase in a one-step treatment of nucleic acids isolated by CF-11 column chromatography to remove contaminating single-stranded RNA. The size-specificity of SDV-D and SDV-Y dsRNAs was shown to be a useful phenotypic marker for in vitro strain differentiation.