Submitted to: Aflatoxin Elimination Workshop Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: October 28, 2004
Publication Date: N/A
Technical Abstract: The objective of this study was to evaluate the Aspergillus flavus pAF28 DNA probe's ability to produce DNA fingerprints for distinguishing among genotypes of Petromyces alliaceus section Flavi, a fungus considered responsible for the ochratoxin A contamination that is occasionally observed in California fig orchards. Petromyces alliaceus (14 isolates), Petromyces albertensis (1 isolate) and seven species of Aspergillus section Circumdati (14 isolates) were analyzed by DNA fingerprinting using a repetitive sequence DNA probe pAF28 derived from A. flavus. The presence of hybridization bands with the DNA probe and the P. alliaceus or P. albertensis genomic DNA indicates a close relationship between A. flavus and Petromyces alliaceus section Flavi. Twelve distinct DNA fingerprint groups or genotypes were identified among the 15 isolates of Petromyces. Species belonging to Aspergillus section Circumdati hybridized only slightly at the 7.0 kb region with the repetitive DNA probe, unlike the highly polymorphic hybridization patterns obtained from P. alliaceus and A. flavus, suggesting very little homology of the probe to Aspergillus section Circumdati genomic DNA. The pAF28 DNA probe offers a tool for typing and monitoring specific P. alliaceus clonal populations and for estimating the genotypic diversity of P. alliaceus in orchards, vineyards or crop fields.