Abstract
Industrial wine yeasts owe their adaptability in constantly changing environments to a long evolutionary history that combines naturally occurring evolutionary events with human-enforced domestication. Among the many stressors associated with winemaking processes that have potentially detrimental impacts on yeast viability, growth, and fermentation performance are hyperosmolarity, high glucose concentrations at the beginning of fermentation, followed by the depletion of nutrients at the end of this process. Therefore, in this study, we subjected three widely used industrial wine yeasts to adaptive laboratory evolution under potassium chloride (KCl)-induced osmotic stress. At the end of the evolutionary experiment, we evaluated the tolerance to high osmotic stress of the evolved strains. All of the analyzed strains improved their fitness under high osmotic stress without worsening their economic characteristics, such as growth rate and viability. The evolved derivatives of two strains also gained the ability to accumulate glycogen, a readily mobilized storage form of glucose conferring enhanced viability and vitality of cells during prolonged nutrient deprivation. Moreover, laboratory-scale fermentation in grape juice showed that some of the KCl-evolved strains significantly enhanced glycerol synthesis and production of resveratrol-enriched wines, which in turn greatly improved the wine sensory profile. Altogether, these findings showed that long-term adaptations to osmotic stress can be an attractive approach to develop industrial yeasts.
Highlights
An evolutionary history of Saccharomyces wine yeasts includes spontaneous and naturally occurring events, such as heterozygosity, nucleotide and structural variations, introgressions, horizontal gene transfers, and hybridization, as well as human-enforced domestication effects [1,2,3,4]
We screened and characterized 17 industrial wine yeast strains for their response to generational and ethanol-mediated changes [24,25], and we chose three of them for this study
Array-CGH profiles of strains 1 and 2 revealed that the most significant diversity in the gene copy number was observed within sub-telomeric regions in almost all chromosomes investigated; there was a generation-mediated gain of genes responsible for telomere maintenance (YRF1 genes) and copper and cadmium detoxification (CUP1 genes) [24]
Summary
An evolutionary history of Saccharomyces wine yeasts includes spontaneous and naturally occurring events, such as heterozygosity, nucleotide and structural variations, introgressions, horizontal gene transfers, and hybridization, as well as human-enforced domestication effects [1,2,3,4] This 7000-year-long history of tight interrelationships between yeast, humans, and human-related environments has resulted in the occurrence of genetic variants within some Saccharomyces cerevisiae lineages that are unique to several subpopulations (i.e., Japanese sake strains). As aforementioned, yeasts have been employed for wine production for thousands of years; they have evolved adaptive functions that enable them to fit in a fluctuating wine fermentation environment [1,2,3,8] Such adaptations can be conferred by nucleotide changes, including base insertions, deletions, or substitutions, and/or by structural genome rearrangements on a large scale, such as chromosome duplications and translocations. These modifications can result in small-scale alterations in gene expression, protein structures, and protein interactions, or large-scale changes in genomic contexts or copy number variations [1,2,3,4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
