Aflatoxins are secondary metabolites produced mainly by the molds Aspergillus flavus and A. parasiticus. Because these compounds are toxic and extremely carcinogenic to animals, they pose a serious risk to human health. The aflatoxin biosynthetic pathway and its genetic regulation have been studied for decades, revealing a well organized aflatoxin pathway gene cluster consisting of 25 genes within a 70 kb DNA region. In order to better understand the molecular mechanisms that control or regulate aflatoxin production, identification of genes (gene profiling) using A. flavus expressed sequence tags (ESTs) and microarrays is currently being performed. Sequencing and annotation of A. flavus ESTs from a normalized A. flavus cDNA library identified 7,218 unique EST sequences. Genes that are putatively involved in aflatoxin biosynthesis, regulation and signal transduction, fungal virulence or pathogenicity, stress response or antioxidation, and fungal development were identified from these ESTs. Gene profiling using microarrays has thus far identified hundreds of genes that are highly expressed under aflatoxin-producing conditions. Further investigations on the functions of these genes are underway. This research is expected to provide information for developing new strategies for control of aflatoxin contamination of agricultural commodities.
Full conference title:
23rd Fungal Genetics Conference
- Fungal Genetics Conference 23rd (2002)