Submitted to: American Chemical Society Symposium Series
Publication Type: Book / Chapter
Publication Acceptance Date: 8/12/2009
Publication Date: 12/20/2009
Citation: Cleveland, T.E., Bhatnagar, D., Yu, J. 2009. Elimination and control of aflatoxin contamination in agricultural crops through Aspergillus flavus genomics. In: Appell, M., Kendra D.F., Trucksess, M.W., Editors. Mycotoxin Prevention and Control in Agriculture. Washington, DC: American Chemical Society Symposium Series 1031. Chapter 7, pp. 93-106.
Interpretive Summary: Aspergilli are opportunistic fungal pathogens most commonly associated with diseases of crops, human and animal systems. Each Aspergillus species can produce a range of secondary metabolites including aflatoxins associated with fungal growth and development. The mechanisms that regulate production of secondary metabolites are not well understood. Genomics technology is a powerful tool in discovering genes and the mechanisms of genetic regulation in an organism. Genomics in Aspergillus flavus has been used in studying aflatoxin formation mechanisms of genetic regulation. In this chapter the progress and future perspective of genomics for elimination of aflatoxin contamination in agriculture have been reviewed.
Technical Abstract: Aflatoxins are polyketide-derivatives initially synthesized by condensation of carbon units into decaketide norsolorinic acid. Aflatoxins are toxic and the most carcinogenic natural compounds. In order to better understand the molecular mechanisms that control aflatoxin production, identification of genes involved in aflatoxin biosynthesis employing a genomics strategy in Aspergillus flavus was carried out. Sequencing and annotation of A. flavus expressed sequence tags (EST) identified 7,218 unique EST sequences. Genes that are involved in or potentially involved in aflatoxin formation were identified from these ESTs. Gene profiling using microarray has thus far identified hundreds of genes that are highly expressed under aflatoxin-producing conditions. Primary annotation of the A. flavus whole genome sequence data showed that there are over two dozens of unique polyketide synthase genes. Further investigations on the functional involvement of these genes in aflatoxin biosynthesis are underway. The results are expected to provide information for developing novel strategies to control aflatoxin contamination.