AFLATOXIN CONTROL THROUGH TARGETING MECHANISMS GOVERNING AFLATOXIN BIOSYNTHESIS IN CORN AND COTTONSEED
Location: Food and Feed Safety Research
Title: Mycotoxin production and prevention of aflatoxin contamination in food and feed
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: February 1, 2007
Publication Date: April 1, 2008
Citation: Yu, J., Payne, G.A., Campbell, B.C., Guo, B., Cleveland, T.E., Robens, J.F., Keller, N.P., Bennett, J.W., Nierman, W.C. 2008. Mycotoxin production and prevention of aflatoxin contamination in food and feed. In: Osmani, S. and Goldman, G. (eds). The Aspergilli: Genomics, Medical Aspects, Biotechnology, and Research Methods, CRC Press, Boca Raton, FL. pp.457-472.
Aflatoxins are the most prominent group of mycotoxins. They are known to be the most toxic and potent carcinogens naturally produced. They are mainly produced by the ascomycetous fungi Aspergillus flavus and A. parasiticus. Over 40 years of research and investigation has generated a wealth of publications on fungal biology, toxicology and toxin biosynthesis. This review focuses on the most pertinent aspects of aflatoxin biosynthesis, and prevention of aflatoxin contamination of food commodities are discussed. Over the past decade, significant progress has been made in deciphering the aflatoxin biosynthetic pathway. All 29 genes of the aflatoxin biosynthetic pathway gene cluster have been cloned. Characterization of these genes, their encoded enzymes, as well as the regulation of gene expression, has been reported. Sterigmatocystin (ST) or dihydrosterigmatocystin (DHST), the penultimate precursor of aflatoxins, is produced by several species, including Aspergillus versicolor and Aspergillus nidulans. ST and DHST are toxic and carcinogenic. They share strikingly similar common biochemical pathways, homologous genes and regulatory mechanisms, to aflatoxin synthesis in A. flavus. The ST biosynthetic pathway and genes are discussed as well.