Selection of Calabrian strains of Saccharomyces sensu stricto for red wines

Phenolic compounds provide important quality attributes to red wines interacting with the organoleptic impact of wines. Yeast mannoproteins can interact with grape phenolic compounds, responsible for colour and antioxidant activity of wines. The aim of this work was to perform oenological characterisation and specific selection of Calabrian strains of Saccharomyces sensu stricto. Among the considered traits, the aptitude of the yeast to preserve grape pigments and colour intensity was included. Among the best six yeast strains – Sc2731, Sc2742, Sc2756, Sc2773, Sc2774, and Sc2823 – strain Sc2742 exhibits the highest Folin–Ciocalteu index and strain Sc2774 the highest colour intensity. These two selected yeasts may be used as starter for the production of red wines in order to preserve grape pigments and colour intensity.

Do Metabolomics and Taxonomic Barcode Markers Tell the Same Story about the Evolution of Saccharomyces sensu stricto Complex in Fermentative Environments?

Yeast taxonomy was introduced based on the idea that physiological properties would help discriminate species, thus assuming a strong link between physiology and taxonomy. However, the instability of physiological characteristics within species configured them as not ideal markers for species delimitation, shading the importance of physiology and paving the way to the DNA-based taxonomy. The hypothesis of reconnecting taxonomy with specific traits from phylogenies has been successfully explored for Bacteria and Archaea, suggesting that a similar route can be traveled for yeasts. In this framework, thirteen single copy loci were used to investigate the predictability of complex Fourier Transform InfaRed spectroscopy (FTIR) and High-performance Liquid Chromatography–Mass Spectrometry (LC-MS) profiles of the four historical species of the Saccharomyces sensu stricto group, both on resting cells and under short-term ethanol stress. Our data show a significant connection between the taxonomy and physiology of these strains. Eight markers out of the thirteen tested displayed high correlation values with LC-MS profiles of cells in resting condition, confirming the low efficacy of FTIR in the identification of strains of closely related species. Conversely, most genetic markers displayed increasing trends of correlation with FTIR profiles as the ethanol concentration increased, according to their role in the cellular response to different type of stress.

Utjecaj različitih fungicidnih pripravaka na rast kvasaca skupine Saccharomyces sensu stricto

Cilj ovog istraživanja bio je utvrditi djelovanje četiri različita fungicidna pripravka na bazi djelatnih tvari mankozeb, kaptan, iprodion i zoksamid na kvasce iz skupine Saccharomyces sensu stricto u laboratorijskim uvjetima. Kvasci iz ove skupine, posebice vrste Saccharomyces cerevisiae i Saccharomyces paradoxus od iznimne su važnosti za proizvodnju vina jer svojim metabolizmom utječu na sam proces fermentacije kao i na stvaranje brojnih spojeva važnih za aromu vina. Filter-disk metodom ispitivan je utjecaj fungicidnih pripravaka koji se primjenjuju za suzbijanje bolesti vinove loze u koncentracijama preporučenima od strane proizvođača kao i u nekim umanjenim i uvećanim koncentracijama. Dokazan je utjecaj pripravaka Cadillac 80WP®, Electis WG® i Stoper® na rast ispitivanih sojeva S. cerevisiae i S. paradoxus dok Kidan® nije imao utjecaj na rast kvasaca ni pri jednoj od ispitivanih koncentracija. Najveći negativan utjecaj imao je Cadillac 80WP® koji je inhibirao rast ispitivanih sojeva čak i pri upola nižim koncentracijama od propisanih. Nije utvrđena razlika u osjetljivosti između vrsta S. cerevisiae i S. paradoxus, dok se istovremeno može zaključiti da su referentni sojevi bili osjetljiviji na Cadillac 80WP®, Electis WG® i Stoper® u usporedbi s autohtonim izolatima.

Whole genome sequencing,de novoassembly and phenotypic profiling for the new budding yeast speciesSaccharomyces jurei

Saccharomyces sensu strictocomplex consist of yeast species, which are not only important in the fermentation industry but are also model systems for genomic and ecological analysis. Here, we present the complete genome assemblies ofSaccharomyces jurei,a newly discoveredSaccharomyces sensu strictospecies from high altitude oaks. Phylogenetic and phenotypic analysis revealed thatS. jureiis a sister-species toS. mikatae,thanS. cerevisiae,andS. paradoxus.The karyotype ofS. jureipresents two reciprocal chromosomal translocations between chromosome VI/VII and I/XIII when compared toS. cerevisiaegenome. Interestingly, while the rearrangement I/XIII is unique toS. jurei,the other is in common withS. mikataestrain IFO1815, suggesting shared evolutionary history of this species after the split betweenS. cerevisiaeandS. mikatae.The number of Ty elements differed in the new species, with a higher number of Ty elements present inS. jureithan inS. cerevisiae.Phenotypically, theS. jureistrain NCYC 3962 has relatively higher fitness than the other strain NCYC 3947Tunder most of the environmental stress conditions tested and showed remarkably increased fitness in higher concentration of acetic acid compared to the othersensu strictospecies. Both strains were found to be better adapted to lower temperatures compared toS. cerevisiae.