Real time quantitative expression study of a polyketide synthase gene related to ochratoxin a biosynthesis in Aspergillus niger

- There is a correlation between pks gene expression and OTA production in Aspergillus niger.
- The pks gene is up-regulated in medium supporting OTA production.
- A high induction of the pks gene can be determined about 12 h before OTA increasing.

Aspergillus niger is a fungus commonly found in foods and feedstuffs and used for biotechnological purposes. It has been reported that some strains are able to produced OTA, a potentially carcinogenic mycotoxin. The aim of this study is to demonstrate that a pks gene expression appears to correlate with OTA production in A. niger indicating a possible role for the product of this gene in OTA biosynthesis We developed a relative quantification gene expression assay by real time reverse transcriptase PCR to demonstrate that pks gene expression appears to correlate with OTA production in A. niger. The pks gene is up-regulated in medium supporting OTA production and a high induction of the pks gene can be determined already about 12 h before an increase in OTA concentration is detected. This work describes for the first time the correlation between pks gene expression and OTA production in A. niger, and represents an important first step in increasing our understanding of the genetic mechanism of OTA biosynthesis.