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Molecular Plant Pathology

New Potato Spindle Tuber Viroid and Tomato Leaf Curl Geminivirus Strains from a Wild Solanum sp.. S. A. A. Behjatnia, Department of Crop Protection, Faculty of Agriculture and Natural Resource Sciences, University of Adelaide, S.A. 5064, Australia; I. B. Dry(2), L. R. Krake(3), B. D. Condé(4), M. I. Connelly(5), J. W. Randles(6), and M. A. Rezaian(7). (2)(3)(7)CSIRO, Division of Horticulture, G.P.O. Box 350, Adelaide 5001, Australia; (4)(5)Department of Primary Industry and Fisheries, P.O. Box 79, Berrimah, N.T. 0828, Australia; (6)Department of Crop Protection, Faculty of Agriculture and Natural Resource Sciences, University of Adelaide, S.A. 5064, Australia. Phytopathology 86:880-886. Accepted for publication 23 April 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/Phyto-86-880.

Three distinct viruslike agents were isolated from a wild, symptomless Solanum sp. suspected of being a natural reservoir of tomato leaf curl geminivirus. Two of these contained circular DNA genomes of approximately 2.7 kb and were identified as geminiviruses. Restriction analysis and partial sequencing of viral DNA indicated that the two geminiviruses are related to, but distinct from, the Australian strain of tomato leaf curl virus. These viruses were not mechanically transmissible; however, a mechanically transmissible disease agent was also present, which caused stunting of infected tomato plants followed by shoot elongation and hairlessness. Analysis of nucleic acids from sap-inoculated tomato plants revealed the presence of a circular RNA, which was isolated and shown to be the causal agent of the transmissible disease. The complete nucleotide sequence of this 356-nucleotide RNA revealed that it was a sequence variant of potato spindle tuber viroid.