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Physiology and Biochemistry

Comparative Characterization of Two Luteoviruses: Beet Western Yellows Virus and Barley Yellow Dwarf Virus. Adrianna D. Hewings, Department of Plant Pathology, University of Illinois, 1102 South Goodwin, Urbana 61801, The first author is presently Research Plant Pathologist, USDA-ARS Foreign Disease-Weed Science Research Unit, Fort Detrick, Bldg. 1301, Frederick, MD 21701; Cleora J. D'Arcy, Department of Plant Pathology, University of Illinois, 1102 South Goodwin, Urbana 61801. Phytopathology 76:1270-1274. Accepted for publication 12 June 1986. 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, 1986. DOI: 10.1094/Phyto-76-1270.

A legume isolate of beet western yellows virus (BWYV-CA) and a vector nonspecific isolate of barley yellow dwarf virus (BYDV-PAV-IL) were characterized. An associated top component (BWYV-CA-TC) was isolated with BWYV-CA. BWYV-CA-TC had a maximum absorbance at 275 nm, an s_20.w of 62 S, buoyant densities of 1.31 g/ml in CsCl and 1.28 g/ml in Cs₂SO₄. No nucleic acid was detected in BWYV-CA-TC and the particles were not infectious. BWYV-CA had a maximum absorbance at 259 nm, an s_20.w of 114S, and buoyant densities of 1.42 g/ml in CsCl and 1.36 g/ml in Cs₂SO₄. BYDV-PAV-IL had a maximum absorbance at 258 nm, an s_20.w of 106 S, and buoyant densities of 1.41 g/ml in CsCl and 1.35 g/ml in Cs₂SO₄. The relative molecular masses (M_r) of the major proteins of BWYV-CA-TC, BWYV-CA, and BYDV-PAV-IL were 24,000, 24,000, and 22,500, respectively. The M_r of the undenatured RNA species of BWYV-CA was 1.90 x 10⁶ and of BYDV-PAV-IL was 1.85 x 10⁶. In negatively stained preparations of purified particles from sucrose density gradients, particle diameters of BWYV-CA-TC, BWYV-CA, and BYDV-PAV-IL were 23 ± 2, 25 ± 1, and 25 ± 1 nm, respectively.