Fumonisin Production and Bioavailability to Maize Seedlings Grown from Seeds Inoculated with <i>Fusarium verticillioides</i> and Grown in Natural Soils

The fungus <i>Fusarium verticillioides</i> infects maize and produces fumonisins. The purpose of this study was to determine the ability of <i>F. verticillioides</i> to produce fumonisins in synthetic and natural soils and their biological availability to maize roots. Maize seeds were inoculated with a pathogenic strain of <i>F. verticillioides</i> (MRC826) and planted in synthetic and three different natural soils. There were statistically significant reductions in stalk weight and root mass and increased leaf lesions in the MRC826-treated seedlings in all soil types. Fumonisins were detected in all of the soils of seedlings grown from MRC826-inoculated seeds. The fumonisin produced in the soils was biologically available to seedlings as demonstrated by the statistically significant elevation of free sphingoid bases and sphingoid base 1-phosphates in their roots. These results indicate that <i>F. verticillioides</i> produced fumonisins in the autoclaved synthetic and natural soils and that the fumonisin produced is biologically available on the basis of evidence of inhibition of ceramide synthase. Keywords: Fumonisin; <i>Fusarium verticillioides</i>; maize; seedling disease