STUDIES IN HETEROBASIDIOMYCETES .65. DIRECT CYTOPLASM CYTOPLASM CONNECTION - AN UNUSUAL HOST-PARASITE INTERACTION OF THE TREMELLOID MYCOPARASITE TETRAGONIOMYCES-ULIGINOSUS

The cellular interaction of Tetragoniomyces uliginosus and Rhizoctonia sp. was restudied by transmission electron microscopy. During the first stages of interaction a body of medium electron density is visible at the center of the haustorial apex in close association with the plasmalemma. A single micropore is produced between the haustorial filament and the host cell. Cytoplasmic connection via the pore always occurred. The pore membrane is continuous with the plasmalemma of both cells. The protoplasts of both the haustorium and the host cell fuse via the micropore. An electron transparent to dense body occlude the pore. Among basidiomycetes, direct connection between the parasite and host protoplasts represents a hitherto unknown type of parasitic interaction. © 1990 Springer-Verlag.