Mycotoxigenic Potential of Ten Fusarium species Grown on Sorghum and in vitro

Abstract

The objective of this study was to determine the mycotoxigenic potential of 12 Fusarium isolates (10 species), including six isolates (4 species) from sorghum. The species were: F. thapsinum, F. semitectum, F. proliferatum and F. chlamydosporum isolated from molded sorghum seed; F. poae, F. graminearum and F. sporotrichioides from barley seed with Fusarium head blight; F. acuminatum from wheat seed; F. verticillioides from infected corn seed; and F. nygamai isolated from soil. Fumonisin and zearalenone concentrations were measured following incubation on autoclaved sorghum seed for 21 days at 25°C, while fusaric acid was measured in mycelia harvested from Czapek Dox broth cultures. F. thapsinum (SC8 and CS121) and F. semitectum (SC7) produced fusaric acid only (4.59-64.13 mg g-1). F. graminearum (KB172) and F. semitectum (CS152) produced zearalenone only (73.4 and 799.3 μg g-1, respectively). F. proliferatum (CS183), F. verticillioides (TX02) and F. nygamai produced both fumonisin (1.92-6.05 μg g-1) and fusaric acid (39.4-234.17 mg g-1). F. poae (KB652), F. acuminatum (Ark), F. chlamydosporum (CS102) and F. sporotrichioides (KB662) did not produce any of these three mycotoxins. Five of the six Fusarium isolates (three species) isolated from sorghum had mycotoxigenic potential. Fusarium spp. naturally occurring on sorghum in the field have the potential to contribute to mycotoxin contamination, either singly or in combination