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Biophysical Differences Among Prunus Necrotic Ringspot Ilarviruses. J. M. Crosslin, Former graduate student, Washington State University, Irrigated Agriculture Research and Extension Center, Prosser 99350; G. I. Mink, plant pathologist, Washington State University, Irrigated Agriculture Research and Extension Center, Prosser 99350. Phytopathology 82:200-206. Accepted for publication 19 September 1991. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/Phyto-82-200.

Intact nucleoproteins of several isolates of Prunus necrotic ringspot virus (PNRSV) from cherry, peach, almond, and hop resolved as three components in rate-zonal sucrose density gradients and as two or three components on electrophoresis in agarose slab gels. Electrophoretic mobilities of the various nucleoprotein components differed among isolates. When electrophoresis was conducted on cellulose acetate sheets, PNRSV nucleoproteins resolved as single bands with marked differences in mobility noted among isolates. These results suggest that net surface charge is primarily responsible for differences in relative mobility among isolates, while differences in size of nucleoprotein components cause the different band patterns seen in agarose gels. Some differences in electrophoretic migration of the three genomic RNAs were noted among isolates under nondenaturing conditions. These differences were less pronounced among isolates than the differences in nucleoprotein migration. Relative molecular weights of coat protein subunits, determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), varied among isolates within a range of about 27–29 kDa but were constant for individual isolates.