Transcriptome analysis of wine hybrids from Saccharomyces sensu stricto using DNA chip technology in enological conditions.

COMBINA M., GONZALEZ S., PANADERO J., BARRIO E., QUEROL A.

Oropesa del Mar, Castellón, España

Simposio; XXIV Internacional Specialized Symposium on Yeast (ISSY 2005).; 2005

Universidad de Valencia

Many genera and species of yeasts are found in the musts, but the genus Saccharomyces, and mainly the species S. cerevisiae, is responsible for alcoholic fermentation. However, other species of the Saccharomyces “sensu stricto” complex like S. bayanus, whose specific ecological niche is wine making at low temperature, or S. paradoxus that has been described as the main yeast in Croatian wines, are also found in fermentation processes. Recently, several novel yeast isolates from wines were analyzed for the structure of their nuclear and mitochondrial genomes, and they have been described as hybrid yeast strains, like S6U. This hybrid yeast has been described as possessing nuclear genomes from both a S. cerevisiae and a S. bayanus-like yeast. Recently we have characterized some yeast strains isolated from wines made in Wädenswil (Switzerland) such as hybrid yeasts between S. cerevisiae and S. kudriavzevii (González et al., submitted). It is important to remark that S. kudriavzevii has never been described in wineries and has only been isolated from natural habitats in Japan. Whether such hybrids originate from events that have taken place in the production environment or in nature is unknown. In the present study analyzed the oenological capability of the two hybrids S6U (S. bayanus x S. cerevisiae) and W27 (S. cerevisiae x S. kudriavzevii) compared with three strains of the species S. bayanus, S. cerevisiae and S. kudriavzevii ) on two grape musts (Macabeo and Tempranillo) in fermentations conducted at four different temperatures (14, 18, 22 and 32ºC) by studying volatile compound production, sugar assimilation and other characteristics influencing the enological properties of wine. Parental yeasts are most adapted and stand out in fermentations under extreme conditions. S. bayanus ferment better at lower temperatures and S. cerevisiae at higher temperatures. However, hybrid yeasts behave particularly well at 14, 18 and 22 ºC. To know why the hybrids are well adapted to these conditions we also analyze the transcriptome using DNA chip technology during the alcoholic fermentations conducted at 18ºC and 32ºC under conditions mimicking and enological environmental.