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Disease Detection and Losses

Double-Stranded RNA from Plants Infected with Closteroviruses. J. Allan Dodds, Associate professor, Department of Plant Pathology, University of California, Riverside 92521; Moshe Bar-Joseph, visiting scientist, Department of Plant Pathology, University of California, Riverside 92521. Phytopathology 73:419-423. Accepted for publication 14 September 1982. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-419.

Expected double-stranded RNA replicative forms (RFs) and unexpected smaller dsRNAs were isolated by chromatography on CF-11 cellulose from extracts of plants infected with closteroviruses. Molecular weights of RFs were estimated to be 13.3 × 10⁶ for citrus tristeza virus (CTV) by electron microscopy, 8.4 × 10⁶ for beet yellows virus (BYV) and carnation necrotic fleck virus (CNFV), and 4.6 × 10⁶ for apple chlorotic leafspot virus (ACLSV) by gel electrophoresis. The patterns of dsRNA segments resolved by polyacrylamide gel electrophoresis were distinct for each virus, but were sufficiently similar for BYV, CNFV, and CTV to be diagnostic for closteroviruses. There was little variation in the pattern of dsRNA segments detected in extracts from groups of plants of a single host, from different tissue sources of a single host, from different hosts, and from the first pellet normally discarded from a CTV and BYV purification scheme. A higher yield of dsRNA was recovered from bark or from recently expanded leaves than from other sources. Sufficient amounts of dsRNA were routinely obtained from only 0.2 to 7.0 g of tissue.