Production of trichothecenes by isolates of Fusarium poae from Argentinian wheat

AZCARATE, M.P., ALVAREZ, C.L. AND 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 poae is a fungus of increasingly recognized importance. Strains of this species form a major component of the fungal flora of the cereal grains and the fungus is frequently associated with ear blight symptoms on wheat. In addition, F poae strains that are either pathogens or grain contaminants produce various mycotoxins which may pose serious hazards to human and animal health. Fusarium Head Blight (FHB), an important disease affecting wheat production, is mainly associated with these species (Parry et al., 1995): Fusarium avenaceum, F. culmorum, F. graminearum, F. poae and Microdochium nivale. In Argentina, 90 % of the pathogens isolated from blighted heads have been Fusarium graminearum [teleomorph Gibberella zeae (Schwein) Petch] (Galich, 1996). However, there is an increasing prevalence of Fusarium poae when agrometeorological conditions are not favorable to F. graminearum infection (Bottalico, 1998). Seventeen strains of Fusarium poae isolated from Argentinean wheat were screened for the ability to produce T-2 toxin (T-2), diacetoxyscirpenol (DAS) and nivalenol (NIV) on sterilized rice grains cultivated at 25 °C for 15 days and at 10°C for 10 days. The extraction of NIV, T-2 and DAS 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). Toxins 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). Of 17 total isolates, 2 produced DAS, 1 produced T-2 and 10 produced NIV (Table 1). These results suggest that strains of F. poae isolated from Argentinean wheat pose a risk for consumer health to be evaluated, due to their ability to produce mycotoxins. For that reason it is an urgent need of monitoring the incidence of F. poae and their mycotoxins in Argentinean wheat under different agrometeorological conditions.