The vintage effect overcomes the terroir effect: a three year survey on the wine yeast biodiversity in Franciacorta and Oltrepò Pavese, two northern Italian vine-growing areas

Abstract

The vintage effect overcomes the terroir effect: a three year survey on the wine yeast biodiversity in Franciacorta and Oltrepò Pavese, two northern Italian vine-growing areas analyses, the year of isolation (vintage) proved to be a factor that significantly affected the biodiversity of the yeast species, whereas the geographical site (terroir) was not. Seventy-five per cent of S. cerevisiae isolates gathered in a unique cluster at a similarity level of 82 %, while the remaining 25 % were separated into minor groups without any evident relationship between d-PCR profile and territory, year or source of isolation. However, in six cases a similar strain appeared at the harvesting time both in Franciacorta and Oltrepò Pavese areas, whereas surprisingly no strain was reisolated in the same vineyard or cellar for consecutive years. INTRODUCTIONIn winemaking, yeasts are essential for the transformation of grape sugars into ethanol and carbon dioxide through alcoholic fermentation; nonetheless, due to their specific enzymic activities and cell autolysis, they can also generate typical sensorial characteristics in wine, like secondary flavours and smoothness (Romano et al., 2003a). Although selected Saccharomyces strains are usually added by oenologists as starter cultures to control the fermentative process, several micro-organisms enter the must from the vineyard environment, winery facilities and cellar equipment, and these can affect the quality of the end product. Nowadays, for a certain style of wines, the use of the 'so called' autochthonous yeasts is considered essential in providing for the valorization and preservation of the environmental microbial biodiversity (Pretorius, 2000). In 3These authors contributed equally to this paper.Abbreviations: ADY, active dry yeast; CE, capillary electrophoresis; ITS, internal transcribed spacer; LSD, least significant difference; PCA, principal component analysis; UPGMA, unweighted pair group method with arithmetic means.

Cellar-Associated Saccharomyces cerevisiae Population Structure Revealed High-Level Diversity and Perennial Persistence at Sauternes Wine Estates

“…Previous consecutive-year follow-up studies reported contrasting results concerning the possible establishment of strains as resident at a given winery (8,14). The comparison by AMOVA of samples obtained from wine estate C over a long period revealed that the variation between the most distant years (1993 and 2014) provided more differences than a comparison of different samples from the same year or from successive years (1992 and 1993 or 2013 and 2014).…”

“…A highly discriminating method based on 15 microsatellite markers specific to S. cerevisiae was used for molecular typing at the strain level. In comparison to previous studies based on other methods, such as PFGE, mtDNA RFLP, and inter-delta analysis (6,8,48), this S. cerevisiae ecological study used deep sampling and relied on the robustness of the microsatellite marker method (36,(49)(50)(51), performed with 15 loci as microsatellite markers and providing more sensitivity than previous studies. Multilocus microsatellite analysis allowed us to evaluate the genetic diversity of our population.…”

“…The presence of specific fermentative profiles with perennial persistence over successive years in a given wineproducing area has been highlighted by different authors (13). However, a recent study challenged the view of a stable population in a wine environment over time, showing that no S. cerevisiae strain was isolated in the same vineyard or cellar during three consecutive years (8). Until now, very few studies have reported long-term observations of the changes in the S. cerevisiae population over time (14).…”

“…In the last 20 years, many studies have described the genetic diversity of S. cerevisiae isolates from different grape varieties. Molecular methods, such as pulsed-field gel electrophoresis (PFGE) (6), mitochondrial DNA (mtDNA) restriction fragment length polymorphism (RFLP) analysis (7), inter-delta analysis (8), and microsatellite analysis (9), were used to describe the genetic diversity of vineyard-associated S. cerevisiae. Numerous factors, such as climate conditions, geographical locations of the vineyards, fungicide management, grape varieties, and winemaking practices, impact the natural yeast population's diversity (10).…”

Fitness of Selected Indigenous Saccharomyces cerevisiae Strains for White Piceno DOC Wines Production

“…This distribution is conditioned by several factors such as cultivar, vintage and climate and could be influenced by agricultural practices [15,23,24]. In addition, preliminary evidence on the association of wine microbiome and phenotype at regional level suggests a microbial contribution to regional characteristic defined as "terroir" [25,26].…”