ADHESION TO NEMATODES OF CONIDIA FROM THE NEMATOPHAGOUS FUNGUS DRECHMERIA-CONIOSPORA

Conidia of the endoparasitic nematophagous fungus Drechmeria coniospor a adhere to the sensory organs of many nematode species. In some cases the adhesion phase is followed by penetration of the nematode cuticle and subsequent infection. In a study of eight different nematode spec ies and five strains of the fungus only two species were infected: Pan agrellus redivivus was infected by all strains and Ditylenchus dipsaci was infected by four strains, although the conidia of all fungal stra ins adhered to all of the nematode species tested. Treatment of the ne matode P. redivivus and the conidia of D. coniospora with proteases ga ve a decreased adhesion in contrast to glycosidases, lipases and other enzymes tested. Inhibitory effects on adhesion were obtained after tr eatment of conidia with the carbohydrate N-acetylneuraminic acid and t he amino acids alanine and proline. Hydrophobicity and electrical char ge appear not to be involved in conidial adhesion. A previous hypothes is on the presence of a sialic-acid-specific lectin in this interactio n appears to be incorrect and the present results indicate no involvem ent of carbohydrates in the adhesion process. The results suggest that the adhesion is mediated by protein(s) in the adhesive part of the co nidium binding to protein(s) excreted from the sensory organs of the n ematodes.