Abstract :
[en] Molds are an integral part of our daily lives, and their presence is not always benign. While some molds offer benefits, others produce harmful secondary metabolites called mycotoxins. Approximately 25% of global food supplies are contaminated with these substances, posing a significant threat to human health and contributing to a substantial number of deaths (direct or indirect). The danger lies not only in their high toxicity, even at low concentrations, but also in their remarkable ability to withstand heat during conventional food processing methods. Therefore, they are subject to strict governmental monitoring, control, and regulation.
In addition to mycotoxins, molds produce volatile organic compounds (VOCs), which are essential in intra- and inter-species communication. These VOCs can also serve as biomarkers for identifying the genus, species, and growth stage of the mold. The inherent link between VOCs and fungal metabolism supports the use of these VOCs as a tool for detecting molds and mycotoxin production. Additionally, the study of VOCs helps to identify specific VOCs that have potential as biocontrol molecules.
This thesis has made a significant contribution to the understanding of VOC’s profiles emitted by the two harmful fungal pathogen species Aspergillus flavus and Fusarium verticillioides, known for their respective production of aflatoxins and fumonisins. In addition to an in-depth study of VOCs and mycotoxins during individual inoculation of these fungi, their co-inoculation under different interaction conditions (contact and non-contact) was investigated. Thus, epizonaren and 4-epi-α-arocadiene were associated with contamination by A. flavus and F. verticillioides, respectively. Additionally, the emission of germacrene D during aflatoxin production and α-cedrene during fumonisin production was reported. On the other hand, ethyl 3-methylbutanaote has been recognized for its antifumonisin property. Its mode of action was studied at the level of gene expression following two applications of this ester in the fungal environment. Two opposite reactions were observed depending on the application, while its efficacy as an antifumonisin compound was confirmed.
