COLONIZATION OF GRAPE BERRIES BY THE GENUS FUSARIUM AND TOXIGENITY OF THE MOST COMMON REPRESENTATIVES

Abstract

The aim of the study was to assess mycotoxin-producing fungi, especially from Fusarium genus, in grapes destined for wine production and to test the ability of selected Fusarium strains to produce mycotoxins as deoxynivalenol (DON), diacetoxyscirpenol (DAS), HT-2 (HT-2) toxin, T-2 (T-2) toxin and zearalenon (ZEA). Totally we processed 24 samples, collected from various Slovak localities in year 2012. The total and endogenous mycobiota was determined by the method of direct placing of grape berries on agar plates. Endogenous mycobiota was estimated after the superficial sterilization. The isolation frequency of the Fusarium genus was 83.3%, in the framework of the non-sterilized and also of sterilized berries. The average relative density was relatively low (2.2% - without sterilization, 2.3% - with sterilization). Totally we identified 11 species of the genus Fusarium. The most important species, on the basis of the isolation frequency and relative density, were F. proliferatum and F. sporotrichioides. Selected isolates of this two species were tested for their toxigenity, by means of thin-layer chromatography. Tests of F. proliferatum confirmed only sporadic production of diacetoxyscirpenol, HT-2 and T-2 toxins. Isolates of F. sporotrichioides have demonstrated high ability to produce diacetoxyscipenol, deoxynivalenol and T-2 toxin (100%), 73% produced HT-2 toxin and 50% synthesized zearalenon.