Abstract:Aspergillus oryzae often contains intact biosynthetic gene cluster for producing cyclopiazonic acid (CPA) toxins. As a result, CPAs has been recognized as a potential threat to food safety. Since CPAs may present in different forms of derivatives, we designed a strategy for incorporating exogenous fluorinated precursor into the CPA biosynthesis pathway. The results showed that after 5-F-L-Trp was used as the substrate and a molecular probe, it was accepted as the substrate of the first biosynthetic enzyme CpaS, producing 5-F-cAATrp, the very first biosynthetic intermediate. Meanwhile，5-F-cAATrp seemed an unsuitable substrate for the next catalytic enzyme CpaD, resulting abolishment of downstream tailoring steps and significant accumulation of this compound. The enrichment effect of CPA metabolites by the molecular probe therefore provides a new opportunity for more convenient and specific detection of CPA toxins targeting only one analyte. These findings are of significance for develop new method for detect and control the CPA toxins in Aspergillus-associated food products.
