In vitro and in situ antifungal properties of a Trichoderma asperelloides SKRU-01 against aflatoxigenic aspergillus species

Abstract

This research investigates the potential of using the culture filtrates of Trichoderma asperelloides SKRU-01 as a peanut preservative and/or fungicide against two mycotoxin-producing fungi, Aspergillus flavus and A. parasiticus. The study assessed the effectiveness of culture filtrates SKRU-01 compared to two commercial preservatives and chemical fungicides, both in vitro and in peanuts. In addition, the study investigated the antifungal and antiaflatoxigenic mechanisms of culture filtrates SKRU-01 against mycotoxin-producing strains. The in vitro results demonstrated that culture filtrates SKRU-01 had a significantly stronger inhibitory effect on the growth and spore germination of the two mycotoxin-producing strains compared to sodium benzoate, sodium propionate, and metalaxyl®, but less inhibition than prochloraz®. The study also explored the mode of action of culture filtrates SKRU-01 and found that it impeded the biosynthesis of ergosterol, indicating its antifungal activity was directed towards the plasma membrane as a potential target site. Furthermore, the culture filtrates SKRU-01 inhibited the biosynthesis of methylglyoxal (AFB1 inducer) in a manner that was dependent on the concentration, which represents a novel mechanism of action against aflatoxins. Additionally, the study observed significant impairment of both enzymatic and non-enzymatic antioxidant defense molecules in aflatoxigenic cells, indicating a potential biochemical mechanism of action. The study tested the potential application of the culture filtrates SKRU-01 in eliminating fungal spoilage in peanuts as a model. The results showed that it had a significant effect in preventing both mold density and AFB1 production, compared to commercial preservatives and chemical fungicides. The antiaflatoxigenic property with AFB1 production level was below the public health concern threshold of 20 μg/kg. Overall, the findings suggest that the culture filtrate of T. asperelloides SKRU-01 contained effective biological control agents possessing preservative and fungicidal properties.