Biosintesi e controllo delle micotossine negli alimenti

Mycotoxins are harmful secondary metabolites produced by several widespread environment-contaminating fungi mainly belonging to Fusarium, Aspergillus and Penicillium genera. These compounds can be mutagenic, teratogenic and carcinogenic for animals and humans. In our diet we experience a quite harmful daily consumption of mycotoxin-contaminated foods. But why fungi do produce toxins? And how are their biosynthesis regulated? Some mycotoxins have a clear-cut role in the assessment of pathogenesis, i.e. fumonisins and some trichothecene, in the competition with other organisms, i.e. patulin vs bacteria. In other cases, such as aflatoxins, more than one role can be hypothesised. Several are the inputs able to modulate mycotoxin synthesis. Here we have focused our attention on those whose regulatory mechanisms have been assessed. In particular, some of these pathways seem to have a common factor which is represented by the control exerted by the reactive oxygen species. In fact, when a fungus receives an external stimulus reacts by activating, through a quite well-defined signal cascade, an evident switch in its lifestyle. This profound change also lead to the activation of global gene regulators and, in particular, of transcription factors able to enhance the mycotoxin gene cluster expression. The control exerted by oxidative stress onto the mycotoxin synthesis has lead to use antioxidants of different origin for blocking the synthesis of these harmful compounds both in the field and in the storage. Recently, many natural-based antioxidant or biocontrol-related strategies have been assessed as environment-friendly approaches for controlling the production of many mycotoxins in feed and foodstuffs.