Reclassification of the Penicillium roqueforti group into three species on the basis of molecular genetic and biochemical profiles

Abstract

Penicillium roqueforti is currently divided into two varieties, one used for cheese starter cultures, P. roqueforti var. roqueforti, and one ubiquitous patulin-producing variety, P. roqueforti var. carneum. The ribosomal regions comprising the 5.85 gene and the internal transcribed spacers, ITS I and ITS II, have been analysed from 10 isolates belonging to each variety. The 10 P. roqueforti var. carneum isolates were separated into two groups of five on the basis of 12 base-pair differences in the ITS regions. One of the groups of P. roqueforti var. carneum, in the following designated P. carneum, differed from P. roqueforti var. roqueforti, here designated P. roqueforti, in just two positions, while the other group, here called P. paneum, differed from P. roqueforti in 12 positions. Random Amplified Polymorphic DNA (RAPD) analysis substantiated these findings, and a comparison of secondary metabolites produced by the three groups showed that the P. roqueforti isolates all produce Penicillium Roqueforti (PR) toxin, marcfortines and fumigaclavine A, while the P. carneum isolates produce patulin, penitrem A and mycophenolic acid, as well as unidentified metabolites. P. paneum produces secondary metabolites in five chromophore families including the known mycotoxins patulin and botryodiploidin. On the basis of these findings it is proposed that P. roqueforti is reclassified into three species named P. roqueforti, P. carneum and P. paneum.