Characterization of Aspergillus section Flavi associated with stored grains
Increased frequencies of Aspergillus section Flavi 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...
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Veröffentlicht in: | Mycotoxin research 2024-02, Vol.40 (1), p.187-202 |
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Sprache: | eng |
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Zusammenfassung: | Increased frequencies of
Aspergillus
section
Flavi
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 characterize
Aspergillus
species from section
Flavi
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 as
A. aflatoxiformans
(4 isolates),
A. flavus
(18), and
A. 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 gene
aflR
and the structural genes
aflD
and
aflM
. All strains producing aflatoxins were linked to the presence of
aflR1
and/or
aflR2
, except two isolates that exhibited aflatoxins but from which
aflR1
or
aflR2
were not detected, which may be due to one or more missing or unstudied additional genes involved in aflatoxin production.
AflD
and
aflM
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 of
Trichoderma viride
against
A. flavus
(F5) was assessed at 31.3%.
Trichoderma
reduced total aflatoxins in all treated seeds, particularly those subjected to
Trichoderma
formulation. |
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ISSN: | 0178-7888 1867-1632 |
DOI: | 10.1007/s12550-023-00514-1 |