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POSTERS: Pathogen detection, quantification and diagnosis

PCR assay for rapidly differentiating aflatoxin-producing taxa in Aspergillus section Flavi
Lourena Arone - University of Arizona. Marc Orbach- University of Arizona, Kenneth Callicott- USDA ARS

Humans and animals are exposed to a?atoxins, toxic, carcinogenic fungal metabolites, through consumption of contaminated food and feed. The most important species associated with aflatoxin contaminated crops are members of Aspergilllus section Flavi. Most aflatoxin producers within section Flavi display similar aflatoxin profiles and morphological characteristics resulting in frequent misidentification. DNA based identification of taxa has improved our understanding of the cryptic diversity within Aspergillus section Flavi, but this can require several PCR amplifications, a sequencing facility, and expertise for data analysis. To develop a rapid, accurate and inexpensive assay for identifying aflatoxin producing taxa within Aspergillus section Flavi, primers were designed using ITS, nitrate reductase, ?-tubulin, calmodulin, aflatoxin transcription factor (aflR), and cytochrome P450 monooxygenase (cypA) genes. A multiplex PCR assay was performed on 45 isolates. The PCR assay was capable of differentiating aflatoxin producing species with similar morphology and aflatoxin profiles. The ?-tubulin, nitrate reductase and calmodulin genes were suitable for differentiating among Aspergillus clades while the aflR and cypA genes were suitable for differentiating within the A. flavus clade.