From Georgia and Canada with FTIR: metabolomic of vine and wine related strains

Abstract

Concern is recently growing among wine producers about the importance of introducing high quality wines to the market that exhibit geographical characteristics and complexity (Harvey et al., 2014). Terroir has been defined as the concept that links the sensory features of wine to the environmental conditions of vineyards. Moreover, these elements may condition what has been defined as the microbial biogeography of grapes (Bokulich et al., 2014), as unique microbial strains have been associated with specific geographical locations (Tofalo et al., 2013). Thus, the description of this microbial diversity can be the first step of the selection of a consortium of native yeast microbiota emulating spontaneous fermentation that could be used for the production of wines with a characteristic footprint. In this framework, we investigated the biodiversity of Canadian and Georgian spontaneous vines, maple trees and wineries to investigate the relationship between the ecological characteristics and the metabolomic profile of this indigenous microbiota. These two different regions of isolation represents two different oenological environments, with recent and almost naive (Canada) and ancient (Georgia) oenological history that influenced significantly the related microbial diversity. In this work, we analyzed 207 yeasts strains. One hundred forty four were isolated from different Canadian sites while sixty three from Georgian cellars. All strains were characterized with molecular analysis using ITS and LSU D1/D2 regions for the taxonomic assignment. FTIR (Fourier Transform Infrared Spectroscopy) fingerprint was employed to elucidate if any significant variation exists between strains of different origin and if it is possible to correlate their metabolic profile with the ecological traits. Result showed that the substrate of isolation, and therefore the type of selection, is particularly important in triggering the evolution of the metabolomic characters, as identified by FTIR metabolomic fingerprint