Canadian Forest Service Publications
Detection of double-stranded RNA and virus-like particles in Chondrostereum purpureum and their effects on virulence (Abstract) 1996. Shamoun, S.F.; Valverde, R.A.; Ramsfield, T.D. Page 100 (Vol. 18) in Canadian Journal of Plant Pathology, Proceedings: The Canadian Phytopathological Society, Annual Meeting. June 25-28, 1995, Toronto, Ontario. Canadian Phytopathological Society, Ottawa.
Issued by: Pacific Forestry Centre
Catalog ID: 4604
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Chondrostereum purpureum is a wound pathogen of hardwood trees and is also under evaluation as a mycoherbicide for unwanted brush species in Canadian conifer plantations and utility rights-of-way. Twenty isolates of C. purpureum collected from different host plants across Canada were examined for the presence of double-stranded RNA (dsRNA) elements and virus-like particles (VLPs). Using agarose gel electrophoresis and scanning electron microscopy, dsRNA and VLPs were found in only one isolate (PFC 2064). Two dsRNA fragments with 1600 and 1800 base pairs were detected on 1% agarose gel, while isometric VLPs of 30 nm in diameter were observed. Curing or eliminating dsRNA elements from isolate PFC 2064 was achieved by protoplast isolation and regeneration. Protoplast suspensions were prepared by digesting mycelial mats with lysing enzymes, and the protoplasts were regenerated in a regeneration medium osmotically stabilized with 0.6 M sucrose. When representative dsRNA-containing parent isolate (PFC 2064), two non-cured protoplast regenerated progeny isolates, and 13 dsRNA-free (cured) protoplast regenerated progeny isolates were inoculated into golden delicious apple and dormant black cottonwood cuttings, lesions produced by dsRNA-free progeny were not significantly larger than those produced by the dsRNA-containing isolates. Ongoing research is focused on screening large populations of Canadian and foreign isolates of C. purpureum to determine the prevalence of dsRNA and to elucidate their biological significance with respect to virulence and other characteristics.