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

Abstract

The ability of the yeast Saccharomyces cerevisiae to adapt to the changing environment of industrial processes lies in the activation and coordination of many molecular pathways. The most relevant ones are nutrient signaling pathways because they control growth and stress response mechanisms as a result of nutrient availability or scarcity and, therefore, leave an ample margin to improve yeast biotechnological performance. A standardized grape juice fermentation assay allowed the analysis of mutants for different elements of many nutrient signaling pathways under different conditions (low/high nitrogen and different oxygenation levels) to allow genetic-environment interactions to be analyzed. The results indicate that the cAMP-dependent PKA pathway is the most relevant regardless of fermentation conditions, while mutations on TOR pathways display an effect that depends on nitrogen availability. The production of metabolites of interest, such as glycerol, acetic acid and pyruvate, is controlled in a coordinated manner by the contribution of several components of different pathways. Ras GTPase Ras2, a stimulator of cAMP production, is a key factor for achieving fermentation, and is also relevant for sensing nitrogen availability. Increasing cAMP concentrations by deleting an enzyme used for its degradation, phosphodiesterase Pde2, proved a good way to increase fermentation kinetics, and offered keys for biotechnological improvement. Surprisingly glucose repression protein kinase Snf1 and Nitrogen Catabolite Repression transcription factor Gln3 are relevant in fermentation, even in the absence of starvation. Gln3 proved essential for respiration in several genetic backgrounds, and its presence is required to achieve full glucose de-repression. Therefore, most pathways sense different types of nutrients and only their coordinated action can ensure successful wine fermentation.

Simultaneous Ablation of the Catalytic AMPK α-Subunit SNF1 and Mitochondrial Matrix Protease CLPP Results in Pronounced Lifespan Extension

“…A small but significant increase in OCR is observed in 12-day-old Δ PaSnf1 /Δ PaClpP ( Figure 6A ). This moderate impact on OCR seen upon PaSNF1 ablation is in agreement with the observation that yeast SNF1 only becomes activated upon glucose depletion ( Vallejo et al, 2020 ). If this response is also true in P. anserina , ablation of PaSNF1 should not affect OCR at high glucose concentrations.…”

Genetically Modified Yeasts in Wine Biotechnology

“…Vallejo and co-authors [68] described recently that nutrient signaling pathway genetic manipulation can be a good target of yeast performance improvement during winemaking. Using CRISPR-Cas9 system in commercial wine strain EC1118, PDE2 gene encoding for a phosphodiesterase was deleted.…”

Next Generation Winemakers: Genetic Engineering in Saccharomyces cerevisiae for Trendy Challenges

“…In selection experiments in which SGRP-4X population was employed (four strains of yeast lineages—North American, Sake, West African and Wine European—were outcrossed for 12 generations giving rise to the SGRP-4X population, ~10–100 million random segregants) the ECM38 allele from the North American strain was detected as the effector of the best growth rate when nitrogen-limited conditions were used [ 120 ]. The TORC1 pathway has been seen to act as the main mechanism in nitrogen-limiting adaptation (amongst other genetic elements), which situates the genes involved as interesting targets for modifications to this end [ 118 , 121 , 122 , 123 , 124 , 125 ].…”