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DNA fingerprinting analysis of Petromyces alliaceus (Aspergillus section Flavi)
Cesaria E McAlpin1, Donald T Wicklow
1Mycotoxin Research Unit, USDA, ARS, National Center for Agricultural Utilization Research, Peoria, IL 61604, USA.
Abstract:
The objective of this study was to evaluate the ability of the Aspergillus flavus pAF28 DNA probe to produce DNA fingerprints for distinguishing among genotypes of Petromyces alliaceus (Aspergillus section Flavi), a fungus considered responsible for the ochratoxin A contamination that is occasionally observed in California fig orchards. P. alliaceus (14 isolates), Petromyces albertensis (one 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 with the P. alliaceus or P. albertensis genomic DNA indicates a close relationship between A. flavus and P. alliaceus. Twelve distinct DNA fingerprint groups or genotypes were identified among the 15 isolates of Petromyces. Conspecificity of P. alliaceus and P. albertensis is suggested based on DNA fingerprints. 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 Circum dati 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.
Insights
The Aspergillus flavus pAF28 DNA probe effectively distinguishes Petromyces alliaceus genotypes, crucial for monitoring ochratoxin A contamination in crops. This tool aids in understanding fungal diversity and population dynamics in agricultural settings.
Area of Science:
- Mycology
- Molecular Biology
- Agricultural Science
Background:
- Petromyces alliaceus is linked to ochratoxin A contamination in California fig orchards.
- Accurate identification of fungal genotypes is essential for effective contamination control.
Purpose of the Study:
- To assess the efficacy of the Aspergillus flavus pAF28 DNA probe for genotyping Petromyces alliaceus.
- To differentiate between P. alliaceus genotypes and related fungal species.
Main Methods:
- DNA fingerprinting was performed on 15 P. alliaceus isolates, 1 P. albertensis isolate, and 14 Aspergillus section Circumdati isolates.
- A repetitive sequence DNA probe (pAF28) derived from A. flavus was used for hybridization analysis.
- Hybridization patterns were analyzed to identify distinct genotypes and assess DNA homology.
Main Results:
- Twelve distinct DNA fingerprint groups (genotypes) were identified among the 15 Petromyces isolates.
- A close relationship between A. flavus and P. alliaceus was indicated by hybridization patterns.
- Conspecificity of P. alliaceus and P. albertensis is suggested by similar DNA fingerprints.
- Aspergillus section Circumdati showed minimal hybridization, indicating low DNA homology with the probe.
Conclusions:
- The pAF28 DNA probe is a valuable tool for typing and monitoring specific P. alliaceus populations.
- The probe facilitates the estimation of genotypic diversity of P. alliaceus in agricultural environments.
- This method aids in managing ochratoxin A contamination risks associated with P. alliaceus.
