Occurrence of Fusarium langsethiae on oat kernels in Italy

Fusarium langsethiae Torp & Niremberg, a recently described fungus, is a high-level producer of T-2 and HT-2 toxins. These trichotecenes are related to alimentary toxic aleukia in humans and haematotoxicity and immunotoxicity in animals. F. langsethiae has been reported in oats, wheat and barley in Central and Northern Europe, but it is more problematic in the former crop rather than the latter two. Little is known about the occurrence of this fungus in Italy, where the demand for oat products is rising. During a 4-year survey, 50 organic seed samples were tested for the presence of F. langsethiae. Four hundred seeds per sample were surface sterilized and then placed in 90 mm Petri dishes containing potato dextrose agar (PDA) and incubated 7 days at 21°C. All Fusarium strains were single-spore purified and characterized at species level on the basis of their morphological features on Spezieller Nährstoffarmer Agar (SNA) plates. Morphological identification was confirmed by translation elongation factor 1-α (TEF) gene sequencing. The most represented Fusarium species was F. poae (Peck) Wollenw. F. langsethiae was recovered from thirteen samples and was usually associated with low levels of infected seeds. Interestingly the main agents of Fusarium Head Blight (FHB), F. graminearum and F. culmorum, were almost absent. In order to detect the presence of T-2 and HT-2 toxins on samples, oat seeds were grinded to a fine powder in a blender. After extraction of the toxins from 10 g of the grounded samples with 70% methanol, the extracts were analysed by Rapid One Step Assay (ROSA) T2-HT2 Quantitative Test (Charm Sciences, Inc., USA). Seed samples resulted to be contaminated by T-2 and HT-2 toxins, but it was impossible to find a statistical correlation between F. langsethiae occurrence, infection levels and toxin contamination.