ARS | Publication request: Profiling of Genes Involved in Aflatoxin Production in Aspergillus Flavus by Expressed Sequence Tags and Microarray

Submitted to: Society Of Industrial Microbiology Annual Meeting
Publication Acceptance Date: May 30, 2004
Publication Date: August 1, 2004
Citation: Yu, J., Kim, H., Wilkinson, J.R., Nierman, W.C., Bhatnagar, D., Cleveland, T.E. 2004. Profiling Of Genes Involved In Aflatoxin Production In Aspergillus Flavus By Expressed Sequence Tags And Microarray [abstract]. Society Of Industrial Microbiology Annual Meeting, July 25-29, 2004, Anaheim, California.

Technical Abstract: Aflatoxins are extremely toxic and carcinogenic compounds produced primarily by the fungi Aspergillus flavus and A. parasiticus. Molecular studies on the genetics of aflatoxin biosynthesis established a well organized aflatoxin pathway gene cluster consisting of 25 genes within 70 kb DNA region. Many nutritional and environmental factors are found to affect aflatoxin formation. In order to better understand the molecular mechanism and regulation of aflatoxin biosynthesis and to discover the signal transduction pathway(s) in turning on aflatoxin production, gene profiling through A. flavus expressed sequence tag (EST) and microarray technologies has been carried out. A total of 7,218 unique EST sequences have been identified from a normalized A. flavus NRRL 3357 cDNA library. Microarray containing over 5,000 unique A. flavus gene amplicons has been constructed. Gene profiling under aflatoxin supportive and non-supportive medium conditions and non-aflatoxin-producing mutant strains have been performed. Comparisons and annotation results showed that hundreds of genes were found to be expressed or up-regulated under aflatoxin-producing conditions. Further investigations on their functions are underway by gene knockout experiments. Those genes that initiate aflatoxin formation could be targeted for silencing by genetic engineering of antifungal crops for eliminating aflatoxin contamination of food and feed.