Mycotoxin profile of Fusarium langsethiae isolated from wheat in Italy: production of type-A trichothecenes and relevant glucosyl derivatives

Fusarium langsethiae, formally described as a new species over a decade ago, has been identified as the main producer of HT-2 (HT2) and T-2 (T2) toxins in Europe in small cereal grains. Mycotoxin contamination caused by this Fusarium species can represent a food safety hazard that deserves further attention. In the present work, the mycotoxin profile in wheat cultures of F. langsethiae is presented with particular reference to the production of major type-A trichothecenes and their glucosyl derivatives. F. langsethiae isolates, representative of the major Italian wheat cultivation areas, were tested for the production of T2, HT2, diacetoxyscirpenol (DAS) and neosolaniol (NEO), and relevant glucosyl derivatives. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for the identification and chemical characterization of these metabolites. F. langsethiae isolates under investigation resulted to be potent producers of T2, HT2 and NEO. Furthermore, a well-defined set of isolates, all originating from Central Italy, produced also DAS. All isolates were found to be able to produce HT2 glucosyl derivatives, whereas only traces of T2 glucoside were detected in one sample. Furthermore, two mono-glucosyl derivatives of NEO and one mono-glucoside derivative of DAS were identified and characterized. The screening for the presence/absence of glucosylated trichothecenes in analyzed fungal extracts revealed a general co-occurrence of these derivatives with the parent toxin at levels that could be roughly estimated to account up to 37% of the relevant unconjugated toxin. This is the first report of the production of glucosylated trichothecenes by F. langsethiae cultured on small grains.