ABSENCE OF ASPECIALIZED INTERFACE BETWEEN INTRACELLULAR HYPHAE Of COLLETOTRICHUM LINDEMUTHIANUM AND CELLS OF PHASEOLUS VULGARIS

S ummary The intracellular infection vesicles and primary hyphae of Colletotrichum lindemuthianum (Sacc. & Magn.) Briosi & Cav. invaginate protoplasts of cells of Phaseolus vulgaris L. A matrix composed partly of polysaccharide or glycoconjugates containing vicinal hydroxyl groups separates the fungal wall from the host plasmalemma. Coated vesicles appear to release host material into the matrix by exocytosis. The invaginated region of the host plasmalemma stains normally with phosphotungstic acid, retains adenosine triphosphatase activity and appears normal when freeze‐fractured. This contrasts with the highly modified host plasmalemma surrounding haustoria of many obligately biotrophic fungi. The absence of a specialized host‐parasite interface is discussed in relation to the transient nature of biotrophy in the bean anthracnose disease.