Btn2p is involved in ethanol tolerance and biofilm formation in flor yeast

Abstract

Flor yeasts are a particular kind of Saccharomyces cerevisiae strains involved in Sherry wine biological ageing. During this process, yeasts form a film on the wine surface and use ethanol as a carbon source, producing acetaldehyde as a by-product. Acetaldehyde induces BTN2 transcription in laboratory strains. Btn2p is involved in the control of the subcellular localization of different proteins. The BTN2 gene shows a complex expression pattern in wine yeast, increasing its expression by acetaldehyde, but repressing it by ethanol. A flor yeast strain transcribes more BTN2 than a first fermentation yeast during growth, but less under different stress conditions. BTN2 deletion decreases flor yeast resistance to high ethanol concentrations. Surprisingly, this effect is suppressed by the addition of high amounts of amino acids to the growth medium, indicating that the role of Btn2p protein in amino acid transport is important for ethanol resistance. Btn2p deletion increases the fermentative capacity of flor yeast and its overexpression prevents its growth on nonfermentable carbon sources. BTN2 deletion also affects the biofilm formation ability of flor yeast, and it increases its sliding motility, resulting in increased mat formation. This correlates with an increased transcription of the FLO11 gene, a gene essential for biofilm formation.

Prioritized Expression of BTN2 of Saccharomyces cerevisiae under Pronounced Translation Repression Induced by Severe Ethanol Stress

“…In the present study, we focused on BTN2 whose deficiency induces hypersensitivity to ethanol (Espinazo-Romeu et al, 2008; Yang et al, 2011). BTN2 encodes a v-SNARE binding protein that is involved in intracellular protein trafficking (Kama et al, 2007) and plays a role in protein deposition in the nucleus (Miller et al, 2015).…”

“…BTN2 encodes a v-SNARE binding protein that is involved in intracellular protein trafficking (Kama et al, 2007) and plays a role in protein deposition in the nucleus (Miller et al, 2015). Because Btn2 is important for the correct localization of various proteins, btn2 Δ cells show pleiotropic phenotypes, including decreased resistance to ethanol, acidic pH, hydrostatic pressure, and L -canavanine (Chattopadhyay et al, 2000; Chattopadhyay and Pearce, 2002; Kim et al, 2005; Espinazo-Romeu et al, 2008; Yang et al, 2011). We found that BTN2 mRNA was efficiently translated under severe ethanol stress and that Btn2 protein levels decreased after ethanol elimination.…”

The Microbial Diversity of Sherry Wines

“…Its deletion affects the biofilm formation ability of flor yeasts, and it increases its sliding motility, resulting in increased mat formation. This correlates with an increased transcription of the FLO11 gene, essential for biofilm formation [10]. Similar studies have concentrated on overexpressing genes SOD1, SOD2, and HSP12 in different veil-forming yeast strains showing that the veil formation by these strains took place more rapidly, and the veil was thicker and with higher percentages of viable cells.…”

“…The veil of flor in Sherry wines consists of multicellular aggregates composed, in turn, by yeasts, bacteria, and fungi, with yeasts being the main microorganisms [4,6,[8][9][10][11][12]. Within the different species of yeasts, Saccharomyces cerevisiae is the most popular species found in the different wines elaborated under biological ageing.…”

A Microtiter Plate Assay as a Reliable Method to Assure the Identification and Classification of the Veil-Forming Yeasts during Sherry Wines Ageing

“…Six hundred yeast strains were isolated previously from the veil of flor of "Manzanilla" and "Fino" wines, from the Sanlúcar de Barrameda and Jerez wineries (Cádiz, Spain), respectively [2,17]. After a first screening, using a Mitochondrial DNA restriction analysis and electrophoretic karyotyping by pulsed-field-gel electrophoresis (PFGE) and SSR-Multiplex PCR, eighteen different profiles of Saccharomyces strains were shown and then grouped according to their similarities-eight from "Manzanilla", denoted as MI to MVI, MX and MXVIII, and ten from "Fino", coded as FI to FX, respectively.…”