Project Number: 6435-41420-006-00
Project Type: Appropriated

Start Date: Dec 28, 2010
End Date: Dec 27, 2015

Objective:
1. Use data from genome-wide systematic analysis to determine the molecular and biological changes that occur in A. flavus upon infection of corn and other crops. 2. Identify mechanistic and molecular requirements for transcriptional regulation of aflatoxin biosynthesis and fungal survival to develop targets for intervention. 3. Establish effects of abiotic (environmental, nutritional) factors on fungal development and toxin production by aflatoxin-producing fungi.

Approach:
Aflatoxins (AFs) are polyketide-derived, toxic, and carcinogenic secondary metabolites produced by Aspergillus flavus on corn, peanuts, cottonseed, and tree nuts. While biosynthesis of these toxins has been extensively studied, much less is known about what causes the fungi to produce AFs under certain environmental conditions and only on certain plants. Our goal is to determine the dynamics of interaction among the key nutritionally and environmentally induced transcription factors necessary for production of AF in order to develop novel inhibitors to one or more of these factors to prevent AF formation in crops. We will use gene microarray, yeast two-hybrid, and chromatin immunoprecipitation assays to determine which critical AF transcription-associated proteins are affected by physiological stress, environmental and soil conditions, and interactions of the fungus with plants. Interactions among key known or to be discovered AF biosynthesis regulatory factors, such as LaeA, VeA, AflJ, and AflR, will be examined by these methods. We will examine the effects of known natural (plant-derived, such as volatile aldehydes) inhibitors of AF production on key components of the AF transcription machinery to ultimately design safe, inexpensive chemicals that inhibit proteins unique to fungal secondary metabolite biosynthesis. We expect to identify safe and effective inhibitors for applications on crops intended for consumption by humans or animals.