Forest Oak Woodlands and Fruit Tree Soils Are Reservoirs of Wine-Related Yeast Species

Abstract

A large-scale sampling plan was performed over four years in three different vineyards to evaluate the occurrence of wine-related yeast species in the soils underneath both vines and forest oak and fruit trees close to the vineyards. Ascomycetous fermentative yeasts were present in 27% of 320 soil samples throughout the sampling years, with incidences that could not be related to sampling season. The greatest percentages of occurrence were found in soils under fig (76%), apple (73%), and oak (41 to 55%) trees. Soils were less contaminated under vines (6%), while these yeasts were not recovered from soil underneath chestnut trees. Other soils showed intermediate percentages of occurrence. A total of 139 fermentative ascomycetes were identified from 25 species. Ninety-six isolates came from 21 different non-Saccharomyces species and 43 isolates from four Saccharomyces species. Soils underneath fruit trees had 11 different species. The most common isolates belonged to Lachancea thermotolerans and Torulaspora delbrueckii, while Sacharomyces paradoxus predominated in the soil underneath oak trees. Saccharomyces cerevisiae was found at low frequency (7% of total isolates) during all sampling years under fruit trees, but it was not recovered from vineyard or oak tree soils. The wine spoilage species Zygosaccharomyces bailii was recovered in only one sample of vineyard soil. For a given soil system, the species recovered varied strongly over the years, suggesting the existence of complex yeast communities. In particular, soils in the vicinity of vineyards were natural reservoirs for yeast species of enological interest.

Wine Microbial Consortium: Seasonal Sources and Vectors Linking Vineyard and Winery Environments

“…This is in accordance with the observations of Barata et al [36], who also isolated H. uvarum and P. guilliermondii from damaged grapes. Chandra et al [37] also detected P.…”

“…From an ecological perspective, the likely difference in available carbon sources explains this rupture between vineyard and winery environments. Certainly, Chandra et al [37] demonstrated the higher incidence of WMC saprophytic yeast species in soils under fruit trees or oak forests probably benefiting from the sugar released by decaying fruits or foliage. Accordingly, in vineyard soils, where grapes are not left to decay, WMC yeasts were very rare [35,37], explaining their weak incidence when metagenomic techniques are used [53] and rotten grapes are not sampled [49].…”

“…Certainly, Chandra et al [37] demonstrated the higher incidence of WMC saprophytic yeast species in soils under fruit trees or oak forests probably benefiting from the sugar released by decaying fruits or foliage. Accordingly, in vineyard soils, where grapes are not left to decay, WMC yeasts were very rare [35,37], explaining their weak incidence when metagenomic techniques are used [53] and rotten grapes are not sampled [49]. On the contrary, the absence of S. cerevisiae in vine bark was not in accordance with other reports [35,[54][55][56].…”

The Rise of Wine among Ancient Civilizations across the Mediterranean Basin

“…The predominant fermenting species is Saccharomyces cerevisiae, which is very rare in natural habitats. Albeit in low numbers and frequency of occurrence, its reservoirs are mainly soils under fruit trees and oaklands, thriving on sap fluxes and benefiting from decaying fruits and foliage and oak bark [29,30]. Rotten grape berries in the wild develop a succession of saprophytic aerobic microorganisms (yeasts, molds and acetic bacteria) that soon deplete carbon sources with little ethanol yield and produce objectionable metabolites such as acetic acid [31].…”

The functional microbiome of grapevine throughout plant evolutionary history and lifetime

“…The cropping system as a whole, however, has a substantial influence on the diversity and composition of leaf microbiome, with significant differences found between organic and conventional farming (Barroso-Bergadà et al, 2021;Castañeda et al, 2018;Kernaghan et al, 2017;Miura et al, 2019). Finally, several studies investigated whether forest patches or orchards adjacent to grapevine plots structure the grapevine leaf microbiome, with varying results (Castañeda et al, 2018;Castañeda and Barbosa, 2017;Chandra et al, 2020;Fort et al, 2016;Miura et al, 2019).…”