Wine yeast phenomics: A standardized fermentation method for assessing quantitative traits of Saccharomyces cerevisiae strains in enological conditions

Abstract

This work describes the set up of a small scale fermentation methodology for measuring quantitative traits of hundreds of samples in an enological context. By using standardized screw cap vessels, the alcoholic fermentation kinetics of Saccharomyces cerevisiae strains were measured by following their weight loss over the time. This dispositive was coupled with robotized enzymatic assays for measuring metabolites of enological interest in natural grape juices. Despite the small volume used, kinetic parameters and fermentation end products measured are similar with those observed in larger scale vats. The vessel used also offers the possibility to assay 32 volatiles compounds using a headspace solid-phase micro-extraction coupled to gas chromatography and mass spectrometry. The vessel shaking applied strongly impacted most of the phenotypes investigated due to oxygen transfer occuring in the first hours of the alcoholic fermentation. The impact of grape must and micro-oxygenation was investigated illustrating some relevant genetic x environmental interactions. By phenotyping a wide panel of commercial wine starters in five grape juices, broad phenotypic correlations between kinetics and metabolic end products were evidentiated. Moreover, a multivariate analysis illustrates that some grape musts are more able than others to discriminate commercial strains since some are less robust to environmental changes.

A study of phenotypic plasticity ofSaccharomyces cerevisiaein natural grape juices shed light on allelic variation under balanced selection

“…Two particular effects were investigated: (i) the phenotypic plasticity of yeast fermenting red or white grape musts (GM) was estimated by comparing M15_Sk (red) vs SB14_Sk (white) conditions, reflecting common types of grape juice fermented around the world. (ii) the phenotypic response to micro-oxygenation (µ-Ox) in accordance with enological practices (Peltier et al 2018) was estimated by comparing M15_Sk (shaken) vs M15 (unshaken). In order to have the broadest landscape of phenotypic plasticity, we performed QTLs mapping in two distinct genetic backgrounds derived from commercial starters widely used in wine industry (SB, GN, M2 and F15).…”

“…Similar results were obtained by calculating the % identity of a subset of 5281 polymorphic SNPs extracted from parental genomes (Sharma, personal communication). The relative phenotypic distance between parental strains was estimated using the phenotypic values of eight fermentation traits measured in five grape musts for 35 strains previously obtained (Peltier et al 2018). In order to represent the genetic diversity of commercial starters, the sampled strains belong to the different branches of the tree.…”

“…Panel C. The distribution of the phenotypic distance computed for 35 strains (31 CWS and the four parental strains). The data used eight traits in five grape musts and were obtained from (Peltier et al 2018). Dashed lines shows the relative distance between parental pairs SB vs GN and M2 vs F15.…”

Natural allelic variations ofSaccharomyces cerevisiaeimpact stuck fermentation due to the combined effect of ethanol and temperature; a QTL-mapping study

“…Glucose and Fructose consumed were estimated by enzymatic assay using the kit n° 10139106035 according to manufacturer protocol (R-Biopharm, Germany) and the RS (Residual Sugars) was computed as the sum of remaining glucose and fructose (expressed in g.L -1 ). The linearity of this method was presented in the Additional file 10 and was recently published [61]. Ethanol (%Vol) was measured by infrared reflectance using an Infra-Analyzer 450 (Technicon, Plaisir, France).…”

A new analytical method to measure S‐methyl‐l‐methionine in grape juice reveals the influence of yeast on dimethyl sulfide production during fermentation

“…Eight milliliter micro-vinifications were performed in 13 mL ventilation-cap polypropylene tubes, with orbital shaking at 100 rpm. 31,32 Tube lids were perforated with a 0.5 mm 2 pinhole to allow for CO 2 release. The musts were inoculated using 1 × 10 6 mL −1 cells from overnight cultures as above and un-inoculated control samples were included to control for DMS formed chemically and independent of yeast.…”