Characterization of Aspergillus section Flavi associated with stored grains

AbstractIncreased frequencies ofAspergillus sectionFlavi and aflatoxins in cereal grains have been seen in recent years due to changes in climate circumstances, such as high temperatures and drought. To assess the microbiological risks of contamination, it is critical to have a reliable and accurate means of identifying the fungi. The main goal of this study was to characterizeAspergillus species from sectionFlavi obtained from twenty-three samples of barley and maize grains, gathered from different markets in Qena, Egypt, using morphological and molecular techniques. Twenty-three isolates were chosen, one isolate from each sample; they were identified asA. aflatoxiformans (4 isolates),A. flavus (18), andA. parasiticus (1). The existence of four aflatoxin biosynthesis genes was also investigated in relation to the strains ’ ability to produce total aflatoxins and aflatoxin B1, focusing on the regulatory geneaflR and the structural genesaflD andaflM. All strains producing aflatoxins were linked to the presence ofaflR1 and/oraflR2, except two isolates that exhibited aflatoxins but from whichaflR1 oraflR2 were not detected, which may be due to one or more missing or unstudied additional genes involved in aflatoxin production.AflD andaflM genes were amplified by 10 and 9 isolates, respectively. Five samples of barley and maize were contaminated by aflatoxins. Fifteen isolates were positive for producing total aflatoxins in the range of 0.1 –240 ppm. Antagonistic activity ofTr...
Source: Mycotoxin Research - Category: Toxicology Source Type: research