Aflatoxin B1 induces chromosomal aberrations and 5S rDNA alterations in durum wheat

Aflatoxin B1 is a secondary metabolite of some fungi that causes very serious diseases in plants, animals and humans. Both cytological studies and molecular techniques revealed that AFB1 at tested concentrations of 5, 10, 15, 20 and 25 μg/ml exhibits genotoxic effect in wheat plants. Several types of chromosomal aberrations have been detected during meiosis; these aberrations include chromosome stickiness, outside bivalents, bridges, laggards, unequal division and micronuclei. The percentage of total abnormalities increased gradually with the increase of toxin concentration but declined again at the highest concentrations. The highest value (2.9%) of abnormalities, detected during meiosis, was in plants treated with 15 μg/ml AFB1 even so, this value decreased to 1.7% in plants treated with the highest concentration (25 μg/ml) of AFB1. The 5S primer generated amplified DNA fragments of 100, 400, 500, 800 and 900 bp in control plants. However, some of these fragments were missing or faint in a number of AFB1-treated plants. Such considerable alterations in DNA profiles of 5S primed amplicons might indicate the generation of various alterations in the inherent property of the 5S rRNA gene sequence.