Metagenomic bacterial diversity and metabolomics profiling of Buttafuoco wine production

Buttafuoco dell’Oltrepo’ Pavese (or Buttafuoco) is an important and renowned red wine, protected by a Denominazione di Origine Controllata (DOC) designation established in 2010, produced in the Northern Italy in the province of Pavia (Italy). The knowledge of factors as the typical microbial terroir and the metabolite composition of the wine is fundamental for producing excellent wines. In this work, two productions of Buttafuoco Storico dell’Oltrep`o Pavese were followed in order to assess the microbial populations through different stages of the wine production chain and the metabolomic composition of the final wines. Microbial terroir was investigated through a metagenomic analysis that revealed a wide microbial consortium which is, for the major taxonomic groups, affected by sampling time over location. Before the metagenomic analysis, being DNA extraction from wine a difficult task, two different approaches were compared for a precise quantification of microbial DNA (bacteria and yeast): digital and real time PCR. Obtained results clearly evidenced that digital PCR being was more sensitive than real time PCR and likely the method of choice for quantifying DNA extracted from processed matrices. Metabolomic profiling, focused on phenolic compounds, was able to clearly distinguish among vineyards and to highlight the presence of discriminating molecules that can be related to the different edaphic conditions.