Genetic safeguard against mycotoxin cyclopiazonic acid production in Aspergillus oryzae
Naoki Kato1, Masafumi Tokuoka, Yasutomo Shinohara
1Chemical Biology Department, Advanced Science Institute, RIKEN, Wako, Saitama, Japan.
Abstract:
Aspergillus oryzae is a fungus widely used in traditional Japanese fermentation industries. Its inability to produce mycotoxins, due to mutation or transcriptional repression of the genes responsible for their biosynthesis, is consistent with the hypothesis that A. oryzae is a domesticated species derived from A. flavus, a wild species that is a well-known producer of aflatoxin. In contrast, the cyclopiazonic acid (CPA) biosynthetic gene (cpa) cluster in A. oryzae contains genes that have been lost in A. flavus. Through targeted gene inactivation, isolation of the corresponding metabolite, and evaluation of biological activity of the metabolite, we demonstrated that an A. oryzae-specific gene-cpaH-mediates the conversion of CPA into the less toxic 2-oxocyclopiazonic acid, a new analogue of CPA. The detoxifying properties of cpaH, which have been lost in the A. flavus pathway, reflect the relationship of the two species.
Related Concept Videos
Fungal Phylum Ascomycota
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Gene Regulation During Sporulation
Microbes in the Production of Fermented Foods
Fungal Group Zygomycota
Gene Regulation in Microbial Communities: Quorum Sensing

