Survival of inoculated Saccharomyces cerevisiae strain on wine grapes during two vintages

Aims: To investigate the influence of a specific ecological niche, the wine grape, on the survival and development of Saccharomyces cerevisiae. Methods and Results: A strain with a rare phenotype was sprayed onto the grape surfaces and monitored through two vintages using a specific indicative medium and analysing the internal transcribed spacer regions in the 5.8S rDNA. During the ripening process, there was a progressive colonization of the surface of the undamaged and damaged grapes by epiphytic yeasts, up to the time of harvest. The damaged wine grapes showed a much greater epiphytic yeast population. However, the inoculated S. cerevisiae strain showed a scarce persistence on both undamaged and damaged wine grapes, and the damaged grapes did not appear to improve the grape surface colonization of this strain. Conclusions: Results indicated that wine grape is not a favourable ecological niche for the development and colonization of S. cerevisiae species. Significance and Impact of Study: Results of this work are further evidence that S. cerevisiae is not specifically associated with natural environments such as damaged and undamaged wine grapes.