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Advisor(s)
Abstract(s)
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
Description
Keywords
fruit tree non-Saccharomyces species oak tree Saccharomyces cerevisiae vineyard soil yeast reservoirs
Pedagogical Context
Citation
Am. J. Enol. Vitic. 71:3 (2020), p. 191-197