New genetic markers for detecting potential indigenous Oenococcus oeni strains able to improve the quality and aroma wine.

New genetic markers for detecting potential indigenous O. oeni strains able to improve the quality and aroma wine. Cappello, M.S.1, De Domenico, S.1, Mita, G.1, Logrieco, A. 2, Zapparoli, G.3 Presenting author's e-mail: maristella.cappello@ispa.cnr.it 1Institute of Science of Food Production, CNR, 73100 Lecce, Italy 2Institute of Science of Food Production, CNR, 70126 Bari, Italy 3Department of Biotechnology, University of Verona, 37134 Verona, Italy Oenococcus oeni is the main lactic acid bacterium involved in Malolactic Fermentation since its high adaptation capacity in wine (1). Extensive studies, carried out over the years, furnished a considerable amount of information on the genetic, physiology and metabolism of this bacterium (2-4). The increasing acquisition of data about the secondary metabolic activities exhibited by O. oeni, which impact strongly to sensory properties of wine, stimulated the investigations on variability within indigenous populations isolated from various winemaking environments. Indeed, strains can modified differently the flavour, quality and safety of wine according to their to metabolic diversity and, due to the economic importance of wine, great interest has been addressed to the study of intraspecific heterogeneity of O. oeni (5, 6). In this work, the detection of several genes involved on important metabolic pathways (i.e. citrate, sulphur and arginine metabolism) was performed on 10 indigenous O. oeni strains of Negroamaro wine, a table red wine (Apulia, Italy). These strains were selected from 95 isolates, collected during a spontaneous malolactic fermentation, according to the results of Amplified Fragment Length Polymorphism (AFLP) analysis. It was screened a total of 16 genes, most of them (11) never assayed before 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), ?-acetolactate decarboxylase (alsD), ?-?acetolactatesynthase (alsS), S-adenosylmethionine synthase (metK) and cystathionine ?-lyase (metC) and resulted negative in the detection of genes encoding cystathionine ?-lyase (metB), ornithine transcarbamylase (arcB) and carbamate kinase (arcC) (table 1.). The sequence of PCR fragments of 11 genes of a representative strain (ITEM 15929) were compared to those of three reference O. oeni strain. The indigenous strain phylogenetically resulted more similar to PSU-1 and ATCC BAA1163 than AWRI B429. The present study provides information on population structure of the species and describes new genetic markers useful for detecting the genetic potential of O. oeni strains to contribute to aroma production and to improve the quality of wine. Table 1. Results of PCR detection of different enzyme-encoding genes in a population of 10 O.oeni strains. Target gene Accession number protein activities Size (bp) Oenococcus oenia (10 strains) MleA KF887214Malolactic enzyme 93710 bgl KF887215?-Glucosidase-related glycosidase6207 estA KF887211Predicted esterase33810 citD KF887220Citrate lyase ?-subunit24510 citE KF887223Citrate lyase ?-subunit87010 citF KF887221Citrate lyase ?-subunit74210 maeP KF887212Putative citrate transporter67610 alsD KF887213?-Acetolactate decarboxylase59710 alsS KF887216???Acetolactatesynthase96810 metK KF887218S-adenosylmethionine synthase 21110 metC KF887222Cystathionine ?-lyase37910 metBCystathionine ?-lyase4160 gshR KF887217Glutathione reductase9787 arcA KF887219Arginine deiminase2497 arcBOrnithine transcarbamylase1810 arcCCarbamate kinase3430 a The total number of strains who own the gene. References 1.Marques, A. P., et al. (2011). Genomic diversity of Oenococcus oeni from different winemaking regions of Portugal. International Micr