ADHESION OF FUSARIUM-OXYSPORUM CONIDIA TO TOMATO ROOTS

The occurence of a binding process between Fusarium oxysporum conidia and the surface of tomato roots was demonstrated in vitro by using a q uantitative assay and a serial washing procedure. The number of conidi a bound per root unit increased with increasing the concentration of t he spores in solution until binding reached saturation. The attachment could be described accurately in terms of the Langmuir adsorption iso therm, indicating the existence of a single class of specific, high-af finity adherence sites on the root: surface. No differences were detec ted in the extent of binding of several strains of F. oxysporum differ ing either in pathogenicity or in host range. Site-specific binding of F. oxysporum conidia may be important in securing the fungal spores a t the root surface, after which germination and other processes requir ed for colonization can proceed.