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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food and Feed Safety Research » Research » Research Project #430859

Research Project: Genetic and Environmental Factors Controlling Aflatoxin Biosynthesis

Location: Food and Feed Safety Research

Project Number: 6054-41420-008-00-D
Project Type: In-House Appropriated

Start Date: Jun 14, 2016
End Date: Jun 13, 2021

Objective:
Objective 1. Identify key genes, using transcriptome analysis of Aspergillus flavus and Aspergillus flavus-crop interaction that are involved in fungal growth, morphogenesis, toxin production and virulence which can be used as targets for intervention strategies. Objective 2. Identify metabolites produced by predicted secondary metabolic gene clusters in Aspergillus flavus, characterize the molecular regulation of their biosynthesis, and determine if they contribute to the fungus’ ability to survive, colonizes host crops and produce aflatoxin. Objective 3. Examine the role of climatic and environmental pressures on the growth, virulence, toxigenic potential, geographical distribution and aflatoxin production by Aspergillus flavus.

Approach:
Aflatoxin contamination in crops such as corn, cottonseed, peanut, and tree nuts caused by Aspergillus (A.) flavus is a worldwide food safety problem. Aflatoxins are potent carcinogens and cause enormous economic losses from the destruction of contaminated crops. While biosynthesis of these toxins has been extensively studied, much remains to be determined regarding regulatory factors, their interactions and gene networks that respond to environmental cues governing fungal development and aflatoxin production. Using an –omics approach (transcriptomics, interactomics, proteomics, metabolomics), fungal genes/proteins will be identified and functionally characterized that are critical for successful host plant colonization and aflatoxin production during interaction of A. flavus with the plant. Interactions of regulatory proteins involved in fungal growth and toxin production, such as AflR and other velvet (VeA)-dependent proteins with global regulators, will be examined to elucidate novel mechanisms governing aflatoxin production and fungal morphogenesis. We will also identify and characterize the biological roles of other secondary metabolites produced by A. flavus, their impact on aflatoxin production and food safety in general. Further, we will better define the molecular mechanisms affected by physiological stress (i.e. changing environmental conditions) to the fungus and plant. We expect to utilize the fundamental knowledge gained from the proposed studies for development of targeted strategies (biological control or host-resistance) to significantly reduce pre-harvest aflatoxin contamination of crops intended for consumption by humans or animals.