Isolation and characterization of the citrinin biosynthetic gene cluster from Monascus aurantiacus.

Monascus aurantiacus produces high amounts of citrinin which is a mycotoxin with nephrotoxic activity. Six putative citrinin biosynthesis genes have been discovered in M. purpureus and at least 10 genes are responsible for its biosynthesis. However, the sequence of citrinin pathway gene cluster in M. aurantiacus has not been reported. Here, the putative sequence of citrinin biosynthetic gene cluster was obtained by a PCR-based strategy for screening a genome fosmid library of M. aurantiacus. A sequence of 43 kb revealed 16 ORFs including the six putative biosynthetic genes reported previous. The putative gene cluster consists of a polytekide synthetase encoding one PKS module, an oxidoreductase gene, three dehydrogenase genes, an acyl-coenzyme A synthetase gene, a membrane transport protein gene, a transcriptional activator gene as well as genes encoding proteins of undefined function.