Bio-molecular characterisation of indigenous Oenococcus oeni strains from Negroamaro wine.

The variation in the coding capacity within Oenococcus oeni can have a significant impact on wine quality. The detection of several genes involved in important metabolic pathways (i.e. citrate, sulphur and arginine metabolisms) was performed on 10 indigenous O. oeni strains from Negroamaro wine, a red table wine (Apulia, Italy). These strains were selected from 95 isolates, collected during spontaneous malolactic fermentation, according to the results of an Amplified Fragment Length Polymorphism (AFLP) analysis. A total of 16 genes were screened, most (11) of which had never previously been assayed on O. oeni. All strains possessed 10 genes encoding enzymes such as malolactic enzyme (mleA), esterase (estA), citrate lyase (citD, citE and citF), citrate transporter (maeP), α-acetolactate decarboxylase (alsD), α- acetolactate synthase (alsS), S-adenosylmethionine synthase (metK) and cystathionine β-lyase (metC) and resulted negative in the detection of genes encoding cystathionine γ-lyase (metB), ornithine transcarbamylase (arcB) and carbamate kinase (arcC). The sequence of PCR fragments of 11 genes of a representative strain (ITEM 15929) was compared to those of three reference O. oeni strains. The indigenous strain was phylogenetically more similar to PSU-1 and ATCC BAA1163 than AWRI B429. This study describes new genetic markers useful for detecting the genetic potential of O. oeni strains to contribute to aroma production and for investigating the population structure of the species.