French Jura flor yeasts: genotype and technological diversity

Abstract

Fifty-four Saccharomyces cerevisiae strains were isolated from Jura "Vin Jaune" velum and characterized by conventional physiological and molecular tests including ITS RFLP and sequence analysis, karyotyping and inter delta typing. ITS RFLP and sequence revealed a specific group of related strains different from the specific profile of Sherry flor yeast caused by a 24 bp deletion in the ITS1 region described by Esteve-Zarzoso et al. (Antonie Van Leeuwenhoek 85:151-158, 2004). Interdelta typing, the most discriminative method, revealed a high diversity of Jura flor yeast strains and gathered strains in clusters unequally shared between the northern and southern part of the Jura vineyard. The assessment of phenotypic diversity among the isolated strains was investigated for three wine metabolites (ethanal, acetic acid, and sotolon) from micro scale velum tests. Except at an early stage of ageing, the production of these metabolites was not correlated to the five genetic groups obtained by interdelta typing, but correlated to the cellar where strains had been isolated. The different strains isolated in a cellar produced mostly one type of velum (thin or thick, grey or white); but thin and grey velums, recognized as responsible for high quality wines, were obtained more frequently for one of the five groups of delta genotypes.

Enological Behaviour of Biofilms Formed by Genetically-Characterized Strains of Sherry Yeast

“…Therefore, the potential association of specific molecular patterns with differences in the performance of the flor yeasts under industrial conditions suggests that molecular methods might be particularly appropriate for identifying and monitoring flor yeast strains with the object of controlling and improving the aging process. This possibility has also been supported by the molecular characterization of different sherry wine aging systems reported by other authors [9,10].…”

FSY1, a horizontally transferred gene in the Saccharomyces cerevisiae EC1118 wine yeast strain, encodes a high-affinity fructose/H+ symporter

“…Most of the new genes acquired by strain EC1118 are present in the Champagne group containing EC1118-related strains, and in a closely related group containing flor yeast (Novo et al, 2009). S. cerevisiae flor yeasts form a film (or velum) on the surface of the wine, and develop an oxidative metabolism in the presence of a high ethanol concentration and low levels of fermentable sugar, essentially fructose (Berlanga et al, 2001;Charpentier et al, 2009). In light of the characteristics of the Fsy1p of strain EC1118, the acquisition of FSY1 by horizontal transfer could confer an advantage either at the end of wine fermentation, when wine yeasts have to ferment this non-preferred sugar in the presence of large amounts of ethanol, or in the oxidative flor conditions.…”

Detection and identification of microorganisms in wine: a review of molecular techniques

“…This is unusual, as this technique typically does not differentiate yeast strains but only species. However, this 24-bp deletion and the resulting banding patterns, after restriction enzyme digests, would only differentiate S. cerevisiae flor strains from non-flor strains [15,32,34]. The results obtained by comparing product length are, however, normally confirmed through comparison of the restriction enzyme banding patterns.…”

“…It has been successfully applied for the identification at the species level to almost all yeasts found in wine, and used in conjunction with other techniques to identify yeasts from various regions around the world, ranging from vineyards in China and Slovenia to Jura fermentations in France [15,58,92]. It has also been used to examine the succession of yeasts during wine fermentations as well as the effects of various winemaking practices, such as cold maceration, have on the yeast population [46].…”

“…For instance, Guillamon et al [44] found the PCR amplification of this region in Metschnikowia pulcherrima generated a 390-bp product while Hanseniaspora uvarum generated a 760-bp product and S. cerevisiae, S. bayanus, and S. pastorianus generated 880-bp fragments. Interestingly, when this technique was applied to 'flor' yeasts in sherry, a 24-bp deletion in the region was found when compared to other S. cerevisiae strains [15,32,34]. This is unusual, as this technique typically does not differentiate yeast strains but only species.…”