Genetic background of ochratoxin A production inPenicillium.

A part of the gene cluster responsible for the production of ochratoxin A inP. nordicum has been characterised recently. The analysed DNA region contains three putative genes: an alcaline proteinase (aspPN), a non-ribosomal peptide synthetase (npsPN) and an polyketide synthase (otapksPN). The last two genes are putative genes of the ochratoxin A biosynthetic pathway. Interestingly theotapksPN gene is present in this form only inP. nordicum but not inP. verrucosum indicating genetic differences between both ochratoxin A producingPenicillium species. The genes in ochratoxin A producingAspergillus species seems to be completely different. It has been demonstrated that thenpsPN gene is actively transcribed inP. nordicum under ochratoxin A producing conditions, indicating that this gene is involved in ochratoxin A biosynthesis.