Metabolites will be identified from maize kernels that stimulate aflatoxin biosynthesis. Metabolites from kernel tissues will be tested using a molecular bioassay that measures activation of specific genes governing aflatoxin biosynthesis. Gaining an understanding of plant components that iinfluence aflatoxin synthesis in A. flavus could allow selective altering of levels of these metabolites in maize by classical breeding.
A maize line that is highly susceptible to A. flavus and aflatoxin contamination will be assayed using a GUS (B-glucuronidase) gene assay for components in the germ and endosperm issues that induce aflatoxin. Inducing activities in hydrophobic and hydrophilic fractions of kernel extracts will be purified using thin layer chromatography, HPLC and column chromatography. Aflatoxin biosynthetic gene activation will be monitored in the presence of the purified kernel fractions using an A. flavus strain which has been transformed with an aflatoxin gene promoter - GUS construct that facilitate the measuring of transcription of an aflatoxin pathway gene.