An official website of the United States government.
The proposed research will utilize a yeast model system to understand why A. sojae does not produce aflatoxins. The related cascade of events involved in the regulation of aflatoxin gene expression will also be characterized. It is anticipated that a better understanding of the non-aflatoxigenicity of natural isolates would provide a rational basis for the preharvest control strategy through development of improved biocompetitive strains by deleting crucial aflatoxin biosynthetic genes.
Aflatoxins are toxic and extremely carcinogenic compounds produced by several species in the Aspergillus flavus group. Aflatoxin contamination of agricultural commodities not only is a health hazard to consumers, but also causes huge economic losses to U.S. farmers. The long-term goal of this research is to understand how aflatoxin biosynthesis is regulated. This could allow genetically defined aflatoxin non-producing biocompetitive strains to be designed, which will out compete toxigenic aspergilli in the field. An approach to elucidate the regulation of aflatoxin biosynthesis is to study a fungus that is closely related to A. flavus and A. parasiticus, but does not produce aflatoxins, such as Aspergillus sojae. This fungus is generally regarded as safe and has been used by the food industry for decades. The proposed research will utilize a yeast model system to understand why A. sojae does not produce aflatoxins. The related cascade of events involved in the regulation of aflatoxin gene expression will also be characterized. It is anticipated that a better understanding of the non-aflatoxigenicity of natural isolates would provide a rational basis for the preharvest control strategy through development of improved biocompetitive strains by deleting crucial aflatoxin biosynthetic genes. It would also remove any doubts about the safety of using A. sojae in food fermentation.