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 quantitative assay and a serial washing procedure. The number of conidia bound per root unit increased with increasing the concentration of the spores in solution until binding reached saturation. The attachment could be described accurately in terms of the Langmuir adsorption isotherm, indicating the existence of a single class of specific, high-affinity adherence sites on the root surface. No differences were detected in the extent of binding of several strains of F. oxysporum differing either in pathogenicity or in host range. Site-specific binding of F. oxysporum conidia may be important in securing the fungal spores at the root surface, after which germination and other processes required for colonization can proceed.