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Cytology and Histology

Antiserum to the Fungus Phialophora mutabilis and Its Use in Enzyme-Linked Immunosorbent Assays for Detection of Soft Rot in Preservative-Treated and Untreated Wood. G. Daniel, Department of Forest Products, Swedish University of Agricultural Sciences, Box 7008, S-750 07 Uppsala, Sweden; T. Nilsson, Department of Forest Products, Swedish University of Agricultural Sciences, Box 7008, S-750 07 Uppsala, Sweden. Phytopathology 81:1319-1325. Accepted for publication 28 September 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/Phyto-81-1319.

Polyclonal antiserum was raised against mycelial extracts from the wood-degrading soft rot fungus Phialophora mutabilis. In enzyme-linked immunosorbent assays (ELISA), the antiserum reacted strongly with its homologous antigen and cross-reacted strongly to moderately with six other soft rot Phialophora species. With the exception of Ceratocystis albida, the serum reacted weakly or not at all with 11 other mold, blue stain, and rot fungi occurring frequently in or on wood. The antiserum also cross-reacted strongly with antigens in extracellular filtrates from P. mutabilis cultures that contained about 40 ng/ml of protein. Ultra-structural and immunocytochemical studies on wood degraded by P. mutabilis showed specific localization of the antibody on the fungal cell wall and certain intracellular structures. Extracellular labeling within soft rot cavities and sites of erosion decay of wood also were noted. The antiserum was assessed by ELISA for detecting the presence of the fungus and soft rot in untreated and preservative-treated wood blocks of pine and birch degraded for periods of 1–12 mo. P. mutabilis was detected in samples from all wood blocks degraded to low or high weight loss. Highest ELISA readings were recorded for wood blocks with highest substrate losses and vice versa.