Molecular identification and characterization of moulds isolated from mouldy cheeses

Mouldy cheese is one of our traditional cheeses. These cheeses are produced by spontenous growth of moulds or intentional added to the cheese. Naturally occurring moulds grow on the surface and inside of the cheese during ripening. Thus, it is important that genotypic identification and characterization of mould species due to their special flavors, smells and tastes. In this study, it is aimed to identify the moulds isolated from traditional mouldy cheeses with morphological and molecular methods, to specify Penicillium roqueforti strains, to determine the probable mycotoxin (roquefortine C and mycophenolic acid) genes and related mycotoxin production potential of selected strains. Moulds isolated from 17 mouldy cheeses including Konya Kuflu Tulum, Divle-Obruk Kuflu Tulum, Erzurum Kuflu Civil and moulds previously isolated from various cheeses (Konya Kuflu, Divle-Obruk, Cecil from Kars region, Tomas from Elazıg-Bingol region, Surk from Hatay region and Tulum from Mediterranean region), total 140 isolates, were purified. Morphological (colony morphologies and microscopic) features of the isolates were investigated. The isolates with different colony morphologies were identified genotypically (28S D1 / D2 ve ITS1-5.8S-ITS2 domains). Mould diversity was composed of 6 different species (Penicillium spp.), containing P. roqueforti, P. commune, P. crustosum, P. spinulosum, P. corylophilum and P. chrysogenum. 28S (LSU) ve 5.8S (ITS) regions were compared by forming two phylogenetic trees. P.roqueforti/ P.paneum/ Penicillium sp. were not able to be distinguished by sequencing LSU region. Although ITS region would not separate P.roqueforti/ P.carneum/ P.psychrosexualis species, it is thought that ITS identification is more efficient than LSU for mould identification. In all of the 21 isolates as P. roqueforti according to ITS region were determined roqA/rds and mpaC genes responsible for production of roquefortine C and mycophenolic acid. As for the LC-MS/ Q-TOF analysis of 3 of the 4 selected strains of P. roqueforti, it was found that roquefortine C produced, but mycophenolic acid was not determined in any extracts of them. In the extract of 1Y5D-coded isolate, both mycotoxins were not detected. Keywords: Mouldy cheese, mold diversity, P.roqueforti, roquefortine C, mycophenolic acid