Mycophagous soil amoeba: Interactions with three plant pathogenic fungi

An amoeba of the order Leptomyxida was isolated from wheat take-all decline soil and was found to attack and lyse hyphae and spores of Gaeumannomyces graminis var. tritici and Phytophthora cinnamomi. The amoeba enveloped portions of hyphae of both fungi and penetrated the cell walls by means of fine holes. One-week old chlamydospores and hyphal swellings of P. cinnamomi were also attacked in this way, protoplast lysis being completed within 1 h. Hyphal fragments which could be ingested by the amoeba were lysed leaving amorphous cell debris. Three-week old chlamydospores of P. cinnamomi were enclosed within large food vacuoles and completely digested in about 20 h. Pigmented conidia of Cochliobolus sativus were transported across the substratum for up to several hours but were not perforated or lysed.