Molecular study of Geotrichum strains isolated from Armada cheese

Abstract

The aim of this work was the genetic characterization at the strain level of 39 presumed Geotrichum candidum isolates isolated throughout the artisanal manufacturing and ripening of Armada cheese and tentatively identified at genus and/or species level by phenotypic characteristics. The molecular identification of the strains included among others the amplification and sequencing of the D1/D2 domains of the 26S rRNA gene. A restriction fragment length polymorphism (RFLP) analysis with the ITS1-5.8S-ITS2 PCR amplicons and a randomly amplified polymorphic DNA (RAPD) analysis with five different primers were carried out. The bands pattern profile obtained through RFLP by enzymatic restriction with HinfI was the same for all the strains studied, which confirmed the classification of the strains at species level. A RAPD-PCR analysis with three different primers was applied to assess the intraspecific diversity, in this way 16 band profiles were obtained for the 39 strains studied by the combined use of primers Ari1 and Omt1. This study contributes to know the occurrence and genotypic biodiversity of G. candidum in Armada cheese.

Keywords: Genetic diversity; Geotrichum candidum; Goats' cheese; Molecular identification; RAPD-PCR; RFLP-PCR.