VIEW ARTICLE

Physiology and Biochemistry

Accumulation of Viroid RNA in Tumor Cells After Double Infection by Agrobacterium tumefaciens and Citrus Exocortis Viroid. J. S. Semancik, Department of Plant Pathology and Cell Interaction Group, University of California, Riverside, CA 92521; L. K. Grill(2), and E. L. Civerolo(3). (2)Department of Plant Pathology and Cell Interaction Group, University of California, Riverside, CA 92521; (3)The Fruit Laboratory, Agricultural Research Service, Beltsville, MD 20705. Phytopathology 68:1288-1292. Accepted for publication 27 March 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1288.

The presence of citrus exocortis viroid (CEV) in tumors induced by A. tumefaciens in CEV-infected tomato has been detected by infectivity of pathogenic RNA and visualization of viroid RNA after polyacrylamide gel electrophoresis. These data correlate directly with the increased level of RNase-resistant ¹²⁵I-CEV following molecular hybridization of nucleic acid preparations from CEV-infected tissue. Primary tumors contained higher levels of the viroid than did apex tissue or fruit. In neoplastic cell cultures CEV can be detected through four subculture passages.