Disentangling the genetic bases of Saccharomyces cerevisiae nitrogen consumption and adaptation to low nitrogen environments in wine fermentation

Abstract

The budding yeast Saccharomyces cerevisiae has been considered for more than 20 years as a premier model organism for biological sciences, also being the main microorganism used in wide industrial applications, like alcoholic fermentation in the winemaking process. Grape juice is a challenging environment for S. cerevisiae, with nitrogen deficiencies impairing fermentation rate and yeast biomass production, causing stuck or sluggish fermentations, thus generating sizeable economic losses for wine industry. In the present review, we summarize some recent efforts in the search of causative genes that account for yeast adaptation to low nitrogen environments, specially focused in wine fermentation conditions. We start presenting a brief perspective of yeast nitrogen utilization under wine fermentative conditions, highlighting yeast preference for some nitrogen sources above others. Then, we give an outlook of S. cerevisiae genetic diversity studies, paying special attention to efforts in genome sequencing for population structure determination and presenting QTL mapping as a powerful tool for phenotype-genotype correlations. Finally, we do a recapitulation of S. cerevisiae natural diversity related to low nitrogen adaptation, specially showing how different studies have left in evidence the central role of the TORC1 signalling pathway in nitrogen utilization and positioned wild S. cerevisiae strains as a reservoir of beneficial alleles with potential industrial applications (e.g. improvement of industrial yeasts for wine production). More studies focused in disentangling the genetic bases of S. cerevisiae adaptation in wine fermentation will be key to determine the domestication effects over low nitrogen adaptation, as well as to definitely proof that wild S. cerevisiae strains have potential genetic determinants for better adaptation to low nitrogen conditions.

Differential Gene Expression and Allele Frequency Changes Favour Adaptation of a Heterogeneous Yeast Population to Nitrogen-Limited Fermentations

“…However, due to its role in oxidative stress and xenobiotic detoxification (Ubiyvovk et al, 2006), this adaptation to nitrogen limitation may be consequence of the stress response mechanisms in the NA strain. Nonetheless, and regardless of the specific molecular mechanisms involved, altogether our results reinforce the idea that alleles coming from a nondomesticated strain (NA) may favour adaptation to low-nitrogen conditions, in this case of a heterogeneous yeast population, as we discussed recently (Kessi-Perez et al, 2020). However, more experimental evidence is necessary to confirm if NA strain is actually adapted to nitrogen limitations and if wild alleles may favour adaptation to nitrogen-limited fermentations.…”

Role of Saccharomyces cerevisiae Nutrient Signaling Pathways During Winemaking: A Phenomics Approach

“…First, wine yeasts are mostly prototrophic and differ from the standard laboratory strains carrying various auxotrophic mutations used as selection markers. Second, some degree of genetic variation in nutrient signaling pathways, such as TORC1, has been found in natural isolates of S. cerevisiae (Kessi-Perez et al, 2019, 2020. Although they constitute a homogenous group, commercial wine starters show wide genetic variability, as reflected by their different sensitivity to inhibitors of nutrient signaling pathways (Vallejo et al, submitted).…”

Nitrogen Sources Added to Must: Effect on the Fermentations and on the Tempranillo Red Wine Quality

“…But that level is dependent on sugar concentration and winemaking practice [1]. Nevertheless, it strongly depends on the genetic bases of yeast species and clones developing during the fermentation process [6][7][8][9]. In this way, some strains consumed nitrogen much more quickly than others [10] so that the selection of yeasts with low nitrogen requirement is a current need in winemaking to avoid stuck fermentations caused by low nitrogen content in grape musts [11].…”