A Differential Proteomic Approach to Characterize the Cell Wall Adaptive Response to CO2 Overpressure during Sparkling Wine-Making Process.

Juan Antonio Porras-Agüera,Teresa García-Martínez,Juan Moreno,Juan Carlos Mauricio,Jaime Moreno-García

doi:10.3390/microorganisms8081188

Juan Antonio Porras-Agüera, Teresa García-Martínez + Show 3 more

Open Access

https://doi.org/10.3390/microorganisms8081188

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Journal: Microorganisms	Publication Date: Aug 4, 2020
License type: CC BY 4.0

Affiliation: University of Córdoba

Abstract

In this study, a first proteomic approach was carried out to characterize the adaptive response of cell wall-related proteins to endogenous CO2 overpressure, which is typical of second fermentation conditions, in two wine Saccharomyces cerevisiae strains (P29, a conventional second fermentation strain, and G1, a flor yeast strain implicated in sherry wine making). The results showed a high number of cell wall proteins in flor yeast G1 under pressure, highlighting content at the first month of aging. The cell wall proteomic response to pressure in flor yeast G1 was characterized by an increase in both the number and content of cell wall proteins involved in glucan remodeling and mannoproteins. On the other hand, cell wall proteins responsible for glucan assembly, cell adhesion, and lipid metabolism stood out in P29. Over-represented proteins under pressure were involved in cell wall integrity (Ecm33p and Pst1p), protein folding (Ssa1p and Ssa2p), and glucan remodeling (Exg2p and Scw4p). Flocculation-related proteins were not identified under pressure conditions. The use of flor yeasts for sparkling wine elaboration and improvement is proposed. Further research based on the genetic engineering of wine yeast using those genes from protein biomarkers under pressure alongside the second fermentation in bottle is required to achieve improvements.

Highlights

The production of sparkling wines following the traditional method implies a characteristic stage where yeast cells are subjected to a second fermentation in sealed bottle and an aging period in contact with lees
32 proteins located in the yeast cell wall were identified in each condition and sampling time, as well as those proteins related to flocculation (Table S1 (Supplementary Materials))
In terms of content, the difference was 3.6-fold and 4.1-fold under PCT2 and NPCT2, respectively, in flor yeast G1. These results suggest a high requirement of cell wall proteins in flor yeast once second fermentation is over, which is probably for a later biofilm formation once nitrogen and fermentable carbon sources are limited [24,27]

Summary

Introduction

The production of sparkling wines following the traditional method (or Méthode Champenoise) implies a characteristic stage where yeast cells are subjected to a second fermentation in sealed bottle and an aging period in contact with lees. This whole stage is known as setting the foam or second fermentation in bottle, and yeast cells must be able to cope with stress mainly caused by ethanol toxicity (10–12% v/v), low temperature (9–12 ◦C), nutrient starvation, and CO2 overpressure (6–7 bar). Cell wall composition varies in response to environment, and the existence of a cell response illustrates its dynamic nature [10,11]. This response to stress, which is known as the “compensatory mechanism”, has been characterized by an increase in the bulk of cell wall proteins, chitin content increase, glucans synthesis, and cell wall components’ redistribution and remodeling [12,13,14]

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