Detection of aflatoxigenic fungi in pistachio nuts by polymerase chain reaction

Abstract

Aflatoxins which are secondary metabolites are low-molecular weight toxins produced by some fungal species such as Aspergillus flavus, Aspergillus nomius and Aspergillus parasiticus. The aflatoxin regulatory gene, aflR, is encoded to generate aflatoxin. To detect aflatoxigenic fungi, DNA was extracted from 22 isolates of A. flavus and A. parasiticus separated from contaminated pistachio nuts to the fungi. Twenty mer forward and reverse gene-specific primers were designed to target aflR gene in the DNA. Positive amplification was achieved only with DNA from aflatoxigenic isolates of A. flavus and A. parasiticus. A 798 bp band was detected in the amplified DNA of each of the isolates indicating that aflatoxin regulatory gene, aflR, was a part of the DNA genome.

Keywords:

• aflatoxin
• Aspergillus flavus
• Aspergillus parasiticus
• pistachio

Acknowledgements

The authors thank the dean of the Research Centre of Kerman Medical University who kindly allowed us to use the laboratory of the research centre.