Distinction Between Aspergillus oryzae and Aflatoxigenic Aspergillus flavus by Rapid PCR Method Based on the...

Area of Science:

• Microbiology
• Mycology
• Genomics

Background:

• Aspergillus oryzae and Aspergillus flavus are closely related species in the Aspergillus section Flavi, sharing ~99.5% genomic similarity.
• A key difference lies in their ability to produce aflatoxin, a carcinogenic mycotoxin synthesized via the aflatoxin biosynthesis gene cluster (ABGC).
• Variations in ABGC deletions exist among section Flavi species and strains.

Purpose of the Study:

• To conduct an in-depth comparative analysis of the ABGC in section Flavi strains.
• To identify unique ABGC deletion patterns in Aspergillus oryzae.
• To develop a reliable method for differentiating Aspergillus oryzae from Aspergillus flavus.

Main Methods:

• Comparative analysis of the ABGC in 30 section Flavi strains, including nuruk isolates.
• Design of four primer sets targeting specific ABGC deletion patterns.
• Application of primer sets for PCR-based species differentiation and in silico PCR analysis using public genomes.

Main Results:

• Aspergillus oryzae exhibits distinct large-scale or locus-specific deletions in the ABGC compared to other section Flavi species.
• The developed primer sets successfully differentiated Aspergillus oryzae from Aspergillus flavus in nuruk isolates with 92% accuracy.
• In silico analysis confirmed the primer sets' consistent ability to distinguish between the two species.

Conclusions:

• Unique ABGC deletion patterns can reliably differentiate Aspergillus oryzae from Aspergillus flavus.
• The developed primer sets offer a rapid, accurate, and practical method for species identification.
• This method is valuable for applications involving nuruk and other Aspergillus section Flavi isolates.