An Aspergillus population (67 strains), isolated from maize in 2003, during the first outbreak of aflatoxin
contamination documented in Northern Italy, was characterised according to gene sequencing data. All strains
were identified as A. flavus by sequencing of \u3b2-tubulin and calmodulin gene fragments. Furthermore, the strains
were analysed for the presence of seven aflatoxin biosynthesis genes in relation to their capability to produce aflatoxin
B1, targeting the regulatory genes aflR and aflS, and the structural genes aflD, aflM, aflO, aflP, and aflQ. The
strains were placed into four groups based on their patterns of amplification products: group I (40 strains) characterised
by presence of all seven amplicons; groups II (two strains) and III (nine strains), showing four (AflM, aflP,
aflO, and aflQ) and three (aflO, aflP, aflQ) amplicons, respectively; and group IV (16 strains) characterised by total
absence of PCR products. Only group I contained strains able to produce aflatoxin B1 (37 out of 40), whereas the
strains belonging to the other groups and lacking three, four or all seven PCR products were non-producers. The
results obtained in this study pointed out that A. flavus was the only species responsible for aflatoxin contamination
in Northern Italy in 2003, and that the aflatoxin gene cluster variability existing in populations can be useful
for understanding the toxicological risk as well as the selection of biocontrol agents