Identification of Fusarium oxysporum f. sp basilici isolated from soil, basil seed, and plants by RAPD analysis

Fifty-two isolates of Fusarium oxysporum, obtained from infected basil plan ts, seed, flower residues, and soil from different growing areas in Italy a nd Israel, were analyzed by random amplified polymorphic DNA-polymerase cha in reaction (RAPD-PCR), coupled to a DNA extraction protocol from colonies grown on Fusarium-selective medium. In a pathogenicity assay, 35 isolates c aused 32 to 92% disease on seedlings of the highly susceptible basil cultiv ar Fine verde, while 17 isolates were nonpathogenic on basil. Thirty of the F. oxysporum f. sp. basilici isolates obtained from soil or wilted plants gave identical amplification patterns using 31 different random primers. Al l tested primers allowed clear differentiation of F. oxysporum f. sp. basil ici from representatives of other formae speciales and from nonpathogenic s trains of F. oxysporum. RAPD profiles obtained from DNA of isolates extract ed directly from cultures grown on Fusarium selective medium were identical to those obtained from DNA extracted from lyophilized mycelia.