Ethanol Inhibits Aflatoxin B Biosynthesis in by Up-Regulating Oxidative Stress-Related Genes.

As the most carcinogenic, toxic, and economically costly mycotoxins, aflatoxin B (AFB) is primarily biosynthesized by and . Aflatoxin biosynthesis is related to oxidative stress and functions as a second line of defense from excessive reactive oxygen species. Here, we find that ethanol can inhibit fungal growth and AFB production by in a dose-dependent manner. Then, the ethanol's molecular mechanism of action on AFB biosynthesis was revealed using a comparative transcriptomic analysis. RNA-Seq data indicated that all the genes except for in the aflatoxin gene cluster were down-regulated by 3.5% ethanol. The drastic repression of aflatoxin structural genes including the complete inhibition of and may be correlated with the down-regulation of the transcription regulator genes and in the cluster. This may be due to the repression of several global regulator genes and the subsequent overexpression of some oxidative stress-related genes. The suppression of several key aflatoxin genes including , , , and may also be associated with the decreased expression of the global regulator gene . In particular, ethanol exposure caused the decreased expression of stress response transcription factor and the overexpression of bZIP transcription factor , CH transcription factors and , together with the enhanced levels of anti-oxidant enzymatic genes including , , , , and Cu, Zn superoxide dismutase gene . Taken together, these RNA-Seq data strongly suggest that ethanol inhibits AFB biosynthesis by via enhancing fungal oxidative stress response. In conclusion, this study served to reveal the anti-aflatoxigenic mechanisms of ethanol in and to provide solid evidence for its use in controlling AFB contamination.