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Stability of Potato Spindle Tuber Viroid in Freeze-Dried Leaf Powder. R. P. Singh, Research Scientist, Research Station, Research Branch, Agriculture Canada; R. E. Finnie, Technician, Research Station, Research Branch, Agriculture Canada. Phytopathology 67:283-286. Accepted for publication 4 August 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-283.

A severe strain of the potato spindle tuber viroid (PSTV) survived up to 6 years in freeze-dried tomato leaves stored at room temperature. In tests to date the mild strains were infectious up to 3 years in tomato and Scopolia sinensis tissues. There was no apparent loss of infectivity during storage for 6 years. Freshly freeze-dried material had infectivity similar to that of the freeze-dried material stored for 6 years. The nucleic acid was extractable from freeze-dried tissues. Analysis of the low-molecular-weight ribonucleic acid, by gel electrophoresis on 20% gels, yielded a well-separated PSTV band in both freeze-dried and nonfreeze-dried tissues. The use of freeze-dried samples facilitates the handling of large amounts of infected material for purification purposes.