Genomic analysis of aflatoxin biosynthesis
2003 年 2003 巻 Suppl3 号 p. 89-97
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2003 年 2003 巻 Suppl3 号 p. 89-97
Aflatoxins are toxic and carcinogenic secondary metabolites produced only by a few species of Aspergillus. Growth of these fungi on a number of plant host species can result in aflatoxin contamination and an unmarketable product. No plant genotype with adequate resistance to aflatoxin contamination is commercially available. The application of genomic sciences to better understand the factors that regulate aflatoxin biosynthesis and describe the interaction of A. flavus with its hosts holds promise for identifying new target sites for control of aflatoxin contamination. Gene expression analysis, along with gene disruption and protein-protein interaction studies, is being used in our laboratory to identify new regulatory circuits in aflatoxin biosynthesis. A targeted DNA microarray composed of 753 elements is being used to identify genes expressed during aflatoxin biosynthesis under a number of physiological conditions. A comparison of conducive and non-conducive conditions for aflatoxin production based on nitrogen source, time, and genetic regulation in A. f lavus has identified several genes differentially expressed during aflatoxin biosynthesis. Many of the differently expressed genes have no known function. Two genes are currently being examined for a role in aflatoxin biosynthesis, an alkyl hydroperoxide reductase (afahpl) and a 14-3-3 gene homolog (mafl). Disruption of (mafl) resulted in loss of aflatoxin production. Yeast two-hybrid analysis identified several genes (including some members of our EST library) that potentially interact with mafl. The function of these genes in aflatoxin biosynthesis is being evaluated.
