Ref ID : 7532
M. Pussard, C. Alabouvette, and R. Pons; [Etude Preliminaire d'une Amibe Mycophage Thecamoeba granifera s. sp. minor (Thecamoebidae, Amoebida)]. Protistologica XV(2):139-149, 1979
Reprint
In File
Notes
An amoeba which feeds on the fungus Fusarium oxysporum f. sp. melonis (the muskmelon wilt pathogen) was isolated by a new culture method. This amoeba is closely related to Thecamoeba granifera Greeff but is distinguished by its smaller size, by being exclusively mycophagous and by the formation of cysts. Mitosis is apparently the acentric metamitotic type, since no kinetic centre was observed by light microscopy. The cyst has a smooth thin wall; germination takes place by rupture of the wall. The amoeba is considered as a new sub-species, Thecamoeba granifera Greeff s. sp. minor. The amoeba feeds on the contents of hyphae and conidia of fungi by perforating the wall and absorbing the cytoplasm. Characteristic granules in the cytoplasm of the species consist partly of phagosomes. The amoeba feeds equally well of Fusarium roseum, F. solani and Verticillium dahliae. Feedig trials with Rhizoctonia solani, Macrophomina phaseolina, Phytophthora cactorum, Pythium sp. and Sclerotinia minor were unsuccessful. Although this mycophagous amoeba was present in three soils which studied, the population was always small, i.e. between 10 and 100 individuals per gram of dry soil.