Relationships between C6−C12 Alkanal and Alkenal Volatile Contents and Resistance of Maize Genotypes to Aspergillus flavus and Aflatoxin Production

An association was found between C6−C12 alkanal and alkenal volatile contents in several maize genotypes and aflatoxin contamination. Volatiles generated from untreated, ground, field resistant (R) maize kernels contained in an inverted lid of a Petri dish affected growth and aflatoxin production by Aspergillus flavus when spores were inoculated on potato dextrose agar in a closed, sealed Petri dish assay. Volatiles from the ground maize genotypes were purged onto Tenax columns and analyzed by GC/MS; C6−C12 aldehydes were more prominent in the GC/MS total ion chromatograms of the R genotypes. Maize genotypes that exhibited a greater inhibition of aflatoxin production in the inverted lid assay also exhibited a larger concentration of linoleic acid in their fatty acid profiles. These results suggest the correlation of decay products of polyunsaturated fatty acids and plant disease resistance and indicate that the lipoxygenase pathway may contribute to this resistance. Keywords: Lipoxygenase products; volatiles; aldehydes; antifungal; aflatoxin