Influence of Botrytis cinerea infection on Champagne wine proteins (characterized by two-dimensional electrophoresis/immunodetection) and wine foaming properties

Proteins are implicated in the foam stabilization of Champagne wines. They may have a grape, yeast, bacteria or fungal origin. Botrytis cinerea is a widespread fungal pathogen, which is the causal agent for gray mold. The first part of this work showed the deleterious effect of the presence of this fungus on the foaming properties of a champenois base wine. Foamability and foam stability were reduced, respectively, by 47.7% and 33.3% in the botrytized wine, as compared to the healthy wine. In a second part, SDS–PAGE and two-dimensional electrophoresis (2-DE), coupled with immunodetection, were used to study (thoroughly) the protein patterns of both wines. With 2-DE and silver-staining detection, the disappearance of numerous spots, located in an acidic pH range, was observed. Indeed, the number of spots detected was about two times more abundant in the healthy wine than in the botrytized one, suggesting that a proteolysis occurred. On the other hand, the presence of new proteins, likely fungal proteins, proteins secreted by the plant as a response to B. cinerea infection, or even protein fragments resulting from partial proteolysis, was detected in the botrytized wine. All these modifications of the wine protein content were undoubtedly due to the presence of B. cinerea and this might be a reason for the loss of foaming properties of Champagne base wines, though no relationship between these two phenomena can be established from the results obtained.