Profiles of mycotoxin production by Fusarium graminearum lineage 7 isolates

ALVAREZ, C.L.; AZCARATE, M.P.; CABRAL, D.; KOLENDER, A.A.; FERNÁNDEZ PINTO, V.

Rosario, Argentina

Simposio; 1ª Conferencia Latinoamericana ICC (International Conference on Cereals and Cereal Products Quality and Safety); 2007

ICC, Inta, Secretaría de Agricultura, Ganadería y Pesca y Alimentos y Bolsa de Comercio de Rosario

From 33 wheat samples, 164 F. graminearum lineage 7 were isolated. A piece of agar (diameter of 1 cm) from a seven-day-old SNA culture of each isolate was placed on 25 g of sterilized rice and cultivated at 25 °C for 15 days and at 10°C for 10 days. The extraction of Deoxinivalenol (DON), Nivalenol (NIV), 15 Acetyldeoxynivalenol (15 AcDON) and 3 Acetyldeoxynivalenol (3-AcDON) was carried out with 125 ml of acetonitrile: ethyl acetate: water (50:41:9). The clean-up was performed with a column packed with charcoal: alumina: celite (0.7:0.5:0.3). Trichothecenes were detected and quantified by gas chromatography with 63Ni electron capture detection (Shimadzu Model GC17, RX-5MS capillary column: 25mx0, 2mm id). The derivatization was carried out with heptafluorbutyric anhydride (Croteau et al. 1994). Standarized data were subjected to principal component analysis (PCA) with the PC-ORD (McCune and Mefford, 1997). Isolate was the operational taxonomic unit (OTU) and the variables were the four toxins produced. According to their mycotoxin profile production isolates could be grouped into 4 groups. One was formed by 14 isolates that produced mainly DON and 3 AcDON (average 41.37 and 169.4 μg/g, respectively. Group 2 has 140 isolates (85.4%). Within this group 94 % of the isolates produced DON (average 68.5 μg/g), 90 % produced 15 AcDON (average 3.6 μg/g), 77.86 % produced 3 AcDON (average 8.38 μg/g) and 27,14% produced NIV (average 1.05 μg/g). The Groups 3 and 4, formed by 6 and 5 isolates respectively, produced NIV and DON in higher quantities. In these groups 15-AcDON was produced in higher quantity than 3-AcDON, 37.5 and 7.69 μg/g, respectively in group 3 and 16.54 and 0.52 μg/g, respectively in group 4. Four groups with different mycotoxin production profiles could be defined. Group 2, with the highest number of isolates, where all the toxins were produced at intermediate values. Group 4 has the greatest production of DON and NIV, with 15 AcDON also produced. Group 3 with a similar profile than 4 but with lower DON production. Group 1 that has the highest value of 3 AcDON with lower values of all the other toxins