Aflatoxin Reduction—A Molecular Strategy

Abstract

Aflatoxins are toxic, carcinogenic compounds produced by the fungi Aspergillus flavus and Aspergillus parasiticus during infection of corn, cotton and peanut. Several novel approaches are being developed using new methods in biotechnology to eliminate preharvest aflatoxin contamination of food and feed. A. flavus strains that produce little or no aflatoxins were discovered that greatly reduced aflatoxin contamination when co-inoculated with aflatoxigenic strains into cotton bolls. These non-toxigenic strains are being tested as potential biocontrol agents. Efforts are underway to clone aflatoxin pathway genes to be used as molecular tools in the production of stable aflatoxin non-producers by genetic engineering for future use in biocontrol applications. Volatile compounds released from plants during pest attack and other plant-derived compounds that inhibit aflatoxin production have been identified. These compounds are being tested for their potential to enhance host plant resistance by inhibition of fungal growth/aflatoxin production. A combined approach utilizing both host defense augmentation and biological control may be necessary to complement existing conventional methods in the eventual total elimination of aflatoxin from the food and feed supply.