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Specific objectives are to utilize the basic information on aflatoxin biosynthesis to: <ol> <li>Identify factors in corn and other crops which induce or impede aflatoxin formation or fungal development.
<li>Transfer the genes that encode resistant factors inhibiting toxin synthesis by genetic engineering of commercial corn or cotton varieties.
<li>Determine the molecular basis for the phenomenon of "natural" non-production in A. flavus group and convergent evolution of toxin synthesis in various Aspergilli.
<li>Utilize Aspergillus genomic sequences to develop rapid, highly sensitive PCR based tests to identify mycotoxigenic fungi and their products in contaminated food products.</ol>
<ol> <li>Molecular markers will be identified using rapid assays that would aid in the success of monitoring and enhancing crop resistance to aflatoxin formation, through comparison of biochemical profiles of selected corn varieties which demonstrate significant differential levels of aflatoxin contamination, but reasonably similar levels of fungal growth in kernels inoculated with Aspergillus flavus.
<li>Reporter gene constructs will be utilized to determine environmental and nutritional signals governing extent of aflatoxin production.
<li>The genes for the identified molecular markers will be transformed into corn and cotton, and the anti-aflatoxin effect of these genes will be assessed.
<li>Comparison of DNA sequences from fungi with identified aflatoxin pathway gene homologs will be used to determine why some Aspergilli synthesize toxins and others do not. The stability of atoxigenic characteristics will be determined, and the effects of individual gene disruptions on aflatoxin biosynthesis and biocompetitive ability of the strains will be assessed.
<li>Genomic sequence information (of candidate genes identified by microarrays) will be used to develop sets of gene specific "universal" primers that can be used to identify potential toxigenic fungi by using real-time PCR protocol without culturing the fungi.</ol>