NATURAL COMPOUNDS FROM TRAMETES VERSICOLOR INHIBIT GROWTH AND MYCOTOXIN BIOSYNTESIS IN DIFFERENT FUNGI

The contamination of food commodities by mycotoxins, health hazardous and carcinogenic secondary metabolites produced by different fungi, has to be closely controlled to safeguard human and animal health. The strategies applied to achieve this aim often induce environmental pollution and are toxic to the end users. Trametes versicolor is a basidiomycete known for its therapeutic effects, mainly based on the production of several glycoproteins and exoglucans displaying anti-tumoral action and anti-oxidative effects. In the culture filtrate of this fungus two different components were identified, one polysaccharidic and one proteic. The exo-polysaccharidic component was analysed by chromatographic separation techniques (Sephacryl S-300) and 1H-NMR analysis showing the presence of highly complexed glucans (alpha- and beta-), with a MW of ~20 kDa. It can be hypothesised that these fungal polysaccharides can act as non-self signals able to modulate secondary metabolism in mycotoxigenic fungi. The proteic component has a clear antimicrobial effect which slows or completely blocks conidia germination at highconcentrations (2% w/v). Proteome maps of extracellular proteins of T. versicolor grown in two conditions, supporting or not the production of bioactive proteins, were analyzed by 2D gel electrophoresis identifying spots with qualitatively and quantitatively differences between the two growth conditions and subsequently characterised by MALDI-TOF. These results might be promising in view of the application of a more environmentally friendly strategy aimed at achieving an improved control of the different toxins which are often present in foods and feeds.