Mycoparasitic relationships. III. Parasitism of Physalospora obtuse by Calcarisporium parasiticum

Abstract

The host–parasite interaction between Physalospora obtusa and the biotrophic contact mycoparasite Calcarisporium parasiticum was studied by light and electron microscopy. After hyphal contact between the two fungi, a contact cell was delimited by a septum in the germ tube apex of C. parasiticum. Subsequently, a portion of the appressed walls of the host–parasite interface was dissolved, creating a large pore through which cytoplasmic exchange occurred. The results of this study explain, in part, how increased nutrient uptake from the host by the parasite is accomplished and dispells the hypothesis that the contact cell increases the permeability of the host plasmalemma to nutrients and required growth factors.