Role of mould occurrence in aflatoxin build-up and variability of Aspergillus flavus isolates from maize grains across India
2017
The present study was conducted to study the role of mould/fungal occurrence on aflatoxin build-up in maize grains and correlation between toxigenic and genetic variability present among isolates of Aspergillus flavus obtained from maize grain samples. Eighty-six maize samples were collected from farmer's fields from various locations among the four maize growing agro-ecological zones of India. Among the microflora of maize grains studied, Aspergillus was the most predominant mould identified. Location Karnal (Haryana) was most sensitive to mould infection; 56.2% of samples), exhibited >20 μg/kg aflatoxin B₁ (AFB₁). On the other hand, Begusarai (Bihar) proves to be a less sensitive area for aflatoxin contamination with 90% of samples exhibiting <20 μg/kg AFB₁. Varied isolates of A. flavus from grain samples were established in culture media and studied for toxigenic variability. In vitro high level variability (8,116.61-0.21 μg/kg) for aflatoxin production potential was found among these isolates. Random amplified polymorphic DNA (RAPD) analysis using 35 OPERON random primers was used to study the correlation between toxigenic and genetic variability. The study exhibited partial relationship between RAPD dendrogram and geographic origin of these isolates, while no correlation was found between genetic variability and toxin production ability among A. flavus isolates studied. Also, three atoxigenic isolates of A. flavus were identified, viz. AF-9, AF-36, and AF-39, endemic to India from the Bihar, Haryana, and Delhi regions, respectively. These strains will need further validation.
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