Profiles of mycotoxin production by Fusarium graminearum lineage 7 isolates

ALVAREZ, CL; AZCARATE MP, CABRAL D, KOLENDER A Y FERNÁNDEZ PINTO V.

Rosario, Santa Fe, Argentina

Conferencia; Conferencia Latinoamericana IIC (International Conference on Cereals and Cereal Products Quality and Safety); 2007

International Association for Cereal Science and Technology

Fusarium Head Blight is an important disease affecting the production of wheat worldwide causing economic losses due to reduction in seed quality and mycotoxin contamination. The objective of this report was to determine the profiles of mycotoxin production of a population of Fusarium graminearum lineage 7. 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 and cultivated at 25°C for 15 days and at 10°C for 10 days. The extraction of Deoxynivalenol (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 packet with charcoal: alumina: celite (0.7:0.5:0.3). Toxins were detected and quantified by gas chromatography with 63Ni electro capture detection (Shimadzu Model GC17, RX-5MS, capillary column: 25mxO, 2mm id). The derivatization was carried out with heptafluorbutyric anhydride (Crocteau 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 (OUT) 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 ug/g, respectively). Group 2 produced has 140 isolates (85.4%). Within this group 94% of the isolates produced DON (average 68.5 ug/g), 90 % produced 15 AcDON (average 3.6 ug/g), 77.86% produced 3 AcDON (average 8.38ug/g) and 27.14% produced NIV (average 1.05 ug/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 ug/g, respectively in group 3 and 16.54 and 0.52 ug/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. 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.