DNA Fingerprinting Analysis of Vegetative Compatibility Groups in Aspergillus flavus from a Peanut Field in Georgia

The ability of species-specific DNA probe pAF28 to correctly match 75 strains of Aspergillus flavus isolated from a peanut field in Georgia with 1 of 44 distinct vegetative compatibility groupings (VCGs) was assessed. Multiple strains belonging to the same VCG typically produced identical DNA fingerprints, with the exception of VCG 17 and VCG 24, which contained strains that showed 83 and 87% similarity, respectively. A. flavus isolates sharing more than 80% of the fragments are recognized as belonging to the same DNA fingerprint group. Each VCG represented by a single isolate produced unique DNA fingerprints. The results provide further evidence that the pAF28 probe is able to distinguish A. flavus VCGs based on DNA fingerprints and can be used to predict the approximate number of VCGs in a sample population. The DNA probe also hybridized strongly and displayed multiple and distinct bands with other species in Aspergillus section Flavi: A. bombycis, A. caelatus, A. nomius, A. pseudotamarii, and A. tamarii. Although individual strains representing Aspergillus spp. in section Flavi produced DNA fingerprints with multiple bands, the banding patterns could not be used to classify these strains according to species.