Differentiation of aflatoxin-producing and non-producing strains of Aspergillus flavus group.

AIMS: Three conventional methods and a multiplex PCR procedure with a set of four primers (Quadruplex-PCR) were used to differentiate between aflatoxin-producing and non-producing strains of the Aspergillus flavus group. METHODS AND
RESULTS: By combining sets of primers for aflR, nor-1, ver-1 and omt-A genes of the aflatoxin biosynthetic pathway, Quadruplex-PCR showed that aflatoxinogenic strains gave a quadruplet pattern, indicating the presence of all the genes involved in the aflatoxin biosynthetic pathway which encode for functional products. Non-aflatoxinogenic strains gave varying results with one, two, three or four banding patterns. A banding pattern in three non-aflatoxinogenic strains resulted in non-differentiation between these and aflatoxinogenic strains. CONCLUSION AND SIGNIFICANCE AND IMPACT OF THE STUDY: Because conventional methods are time-consuming, further studies are needed to develop a rapid and objective technique that permits complete differentiation between aflatoxin-producing and non-producing strains of the A. flavus group.