scholarly journals Saccharomyces cerevisiae FLO1Gene Demonstrates Genetic Linkage to Increased Fermentation Rate at Low Temperatures

2017 ◽  
Vol 7 (3) ◽  
pp. 1039-1048 ◽  
Author(s):  
Rebecca C. Deed ◽  
Bruno Fedrizzi ◽  
Richard C. Gardner
2020 ◽  
Author(s):  
Runze Li ◽  
Rebecca C. Deed

Abstract Background In winemaking, it is standard practice to ferment white wines at low temperatures (10–18 ºC). However, low temperatures increase the fermentation duration and risk of problem ferments, which can lead to significant costs. The length of the lag period at fermentation initiation is one parameter that is heavily impacted by low temperatures. Therefore, the identification of Saccharomyces cerevisiae genes with an impact on fermentation kinetics, such as lag time, is of interest for winemaking. Results We selected a set of 28 S. cerevisiae BY4743 single deletants based on a prior list of candidate open reading frames (ORFs) mapped to quantitative trait loci (QTLs) on chromosomes VII and XIII influencing the duration of fermentative lag time by bulk segregant analysis. Five out of 28 BY4743 deletants, Δapt1, Δcgi121, Δclb6, Δrps17a, and Δvma21, differed significantly in their fermentative lag phase duration compared to BY4743 in synthetic grape medium (SGM) at 15 ºC, over 72 h. Fermentation at 12.5 ºC for 528 h, to show a greater resolution of the lag times, identified the inability of BY4743 Δapt1 to initiate fermentation and confirmed the significantly longer lag times of the BY4743 Δcgi121, Δrps17a, and Δvma21 deletants. The three candidate ORFs were deleted in S. cerevisiae RM11-1a and S288C to perform single reciprocal hemizygosity analysis (RHA). RHA hybrids and single deletants of RM11-1a and S288C were fermented at 12.5 ºC in SGM. Lag time measurements confirmed genetic linkage of CGI121 on chromosome XIII, encoding a component of the EKC/KEOPS complex, to fermentative lag phase. Nucleotide sequences of RM11-1a and S288C CGI121 alleles differed by only one synonymous nucleotide suggesting that codon bias or positional effects might be responsible for the impact of this gene on lag phase duration. Conclusion This research demonstrates a new role of CGI121 in fermentative lag time in S. cerevisiae during fermentation and highlights the applicability of QTL analysis for investigating complex phenotypic traits in yeast, such as fermentation kinetics.


Author(s):  
Runze Li ◽  
Rebecca C Deed

Abstract It is standard practice to ferment white wines at low temperatures (10-18 °C). However, low temperatures increase fermentation duration and risk of problem ferments, leading to significant costs. The lag duration at fermentation initiation is heavily impacted by temperature; therefore, identification of Saccharomyces cerevisiae genes influencing fermentation kinetics is of interest for winemaking. We selected 28 S. cerevisiae BY4743 single deletants, from a prior list of open reading frames (ORFs) mapped to quantitative trait loci (QTLs) on chromosomes VII and XIII, influencing the duration of fermentative lag time. Five BY4743 deletants, Δapt1, Δcgi121, Δclb6, Δrps17a, and Δvma21, differed significantly in their fermentative lag duration compared to BY4743 in synthetic grape must (SGM) at 15 °C, over 72 h. Fermentation at 12.5 °C for 528 h confirmed the longer lag times of BY4743 Δcgi121, Δrps17a, and Δvma21. These three candidate ORFs were deleted in S. cerevisiae RM11-1a and S288C to perform single reciprocal hemizygosity analysis (RHA). RHA hybrids and single deletants of RM11-1a and S288C were fermented at 12.5 °C in SGM and lag time measurements confirmed that the S288C allele of CGI121 on chromosome XIII, encoding a component of the EKC/KEOPS complex, increased fermentative lag phase duration. Nucleotide sequences of RM11-1a and S288C CGI121 alleles differed by only one synonymous nucleotide, suggesting that intron splicing, codon bias, or positional effects might be responsible for the impact on lag phase duration. This research demonstrates a new role of CGI121 and highlights the applicability of QTL analysis for investigating complex phenotypic traits in yeast.


2003 ◽  
Vol 69 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Eric Rosenfeld ◽  
Bertrand Beauvoit ◽  
Bruno Blondin ◽  
Jean-Michel Salmon

ABSTRACT The anaerobic growth of the yeast Saccharomyces cerevisiae normally requires the addition of molecular oxygen, which is used to synthesize sterols and unsaturated fatty acids (UFAs). A single oxygen pulse can stimulate enological fermentation, but the biochemical pathways involved in this phenomenon remain to be elucidated. We showed that the addition of oxygen (0.3 to 1.5 mg/g [dry mass] of yeast) to a lipid-depleted medium mainly resulted in the synthesis of the sterols and UFAs required for cell growth. However, the addition of oxygen during the stationary phase in a medium containing excess ergosterol and oleic acid increased the specific fermentation rate, increased cell viability, and shortened the fermentation period. Neither the respiratory chain nor de novo protein synthesis was required for these medium- and long-term effects. As de novo lipid synthesis may be involved in ethanol tolerance, we studied the effect of oxygen addition on sterol and UFA auxotrophs (erg1 and ole1 mutants, respectively). Both mutants exhibited normal anaerobic fermentation kinetics. However, only the ole1 mutant strain responded to the oxygen pulse during the stationary phase, suggesting that de novo sterol synthesis is required for the oxygen-induced increase of the specific fermentation rate. In conclusion, the sterol pathway appears to contribute significantly to the oxygen consumption capacities of cells under anaerobic conditions. Nevertheless, we demonstrated the existence of alternative oxygen consumption pathways that are neither linked to the respiratory chain nor linked to heme, sterol, or UFA synthesis. These pathways dissipate the oxygen added during the stationary phase, without affecting the fermentation kinetics.


Genetics ◽  
1990 ◽  
Vol 124 (3) ◽  
pp. 515-522
Author(s):  
L P Wakem ◽  
F Sherman

Abstract Approximately 290 omnipotent suppressors, which enhance translational misreading, were isolated in strains of the yeast Saccharomyces cerevisiae containing the psi+ extrachromosomal determinant. The suppressors could be assigned to 8 classes by their pattern of suppression of five nutritional markers. The suppressors were further distinguished by differences in growth on paromomycin medium, hypertonic medium, low temperatures (10 degrees), nonfermentable carbon sources, alpha-aminoadipic acid medium, and by their dominance and recessiveness. Genetic analysis of 12 representative suppressors resulted in the assignment of these suppressors to 6 different loci, including the three previously described loci SUP35 (chromosome IV), SUP45 (chromosome II) and SUP46 (chromosome II), as well as three new loci SUP42 (chromosome IV), SUP43 (chromosome XV) and SUP44 (chromosome VII). Suppressors belonging to the same locus had a wide range of different phenotypes. Differences between alleles of the same locus and similarities between alleles of different loci suggest that the omnipotent suppressors encode proteins that effect different functions and that altered forms of each of the proteins can effect the same function.


2018 ◽  
Author(s):  
Daisuke Watanabe ◽  
Takuma Kajihara ◽  
Yukiko Sugimoto ◽  
Kenichi Takagi ◽  
Megumi Mizuno ◽  
...  

ABSTRACTSake yeast strain Kyokai no. 7 (K7) and its Saccharomyces cerevisiae relatives carry a homozygous loss-of-function mutation in the RIM15 gene, which encodes a Greatwall-family protein kinase. Disruption of RIM15 in non-sake yeast strains leads to improved alcoholic fermentation, indicating that the defect in Rim15p is associated with the enhanced fermentation performance of sake yeast cells. In order to understand how Rim15p mediates fermentation control, we here focused on target-of-rapamycin protein kinase complex 1 (TORC1) and protein phosphatase 2A with the B55Δ regulatory subunit (PP2AB55δ), complexes that are known to act upstream and downstream of Rim15p, respectively. Several lines of evidence, including our previous transcriptomic analysis data, suggested enhanced TORC1 signaling in sake yeast cells during sake fermentation. Fermentation tests of the TORC1-related mutants using a laboratory strain revealed that TORC1 signaling positively regulates the initial fermentation rate in a Rim15p-dependent manner. Deletion of the CDC55 gene encoding B55δ abolished the high fermentation performance of Rim15p-deficient laboratory yeast and sake yeast cells, indicating that PP2AB55δ mediates the fermentation control by TORC1 and Rim15p. The TORC1-Greatwall-PP2AB55δ pathway similarly affected the fermentation rate in the fission yeast Schizosaccharomyces pombe, strongly suggested that the evolutionarily conserved pathway governs alcoholic fermentation in yeasts. It is likely that elevated PP2AB55δ activity accounts for the high fermentation performance of sake yeast cells. Heterozygous loss-of-function mutations in CDC55 found in K7-related sake strains may indicate that the Rim15p-deficient phenotypes are disadvantageous to cell survival.IMPORTANCEThe biochemical processes and enzymes responsible for glycolysis and alcoholic fermentation by the yeast S. cerevisiae have long been the subject of scientific research. Nevertheless, the factors determining fermentation performance in vivo are not fully understood. As a result, the industrial breeding of yeast strains has required empirical characterization of fermentation by screening numerous mutants through laborious fermentation tests. To establish a rational and efficient breeding strategy, key regulators of alcoholic fermentation need to be identified. In the present study, we focused on how sake yeast strains of S. cerevisiae have acquired high alcoholic fermentation performance. Our findings provide a rational molecular basis to design yeast strains with optimal fermentation performance for production of alcoholic beverages and bioethanol. In addition, as the evolutionarily conserved TORC1-Greatwall-PP2AB55δ pathway plays a major role in the glycolytic control, our work may contribute to research on carbohydrate metabolism in higher eukaryotes.


2016 ◽  
Vol 51 (2) ◽  
pp. 89-94
Author(s):  
H Ibrahim ◽  
BO Atolaiye ◽  
MO Aremu

The fermentation of tiger nut (Cyperus esculentus var. sativus) using Saccharomyces cereviseae was carried out under varying temperature: 25oC, 30oC, 35oC, 40oC, 45oC and 50oC respectively and pH of 4.0 which changes due to temperature. The fermentation time was 8 hours for all the temperatures. The effect of temperature on the rate of fermentation of juice from tiger nut was determined using the volume of carbon dioxide produced. Fermentation rate was observed to be highest at 40oC while the pH before and after fermentation were 4.10 - 4.29 and 3.60 - 3.67 respectively. The concentrations of ethanol produced were 13.35 g/L, 27.45 g/L, 31.16 g/L, 36.35 g/L, 33.39 g/L and 28.94 g/L at 25 oC, 30oC, 35oC, 40oC, 45oC and 50oC respectively.Bangladesh J. Sci. Ind. Res. 51(2), 89-94, 2016


F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 679 ◽  
Author(s):  
Jordi Tronchoni ◽  
Estéfani García-Ríos ◽  
Jose Manuel Guillamón ◽  
Amparo Querol ◽  
Roberto Pérez-Torrado

Background: Although Saccharomyces cerevisiae is the most frequently isolated species in wine fermentation, and the most studied species, other species and interspecific hybrids have greatly attracted the interest of researchers in this field in the last few years, given their potential to solve new winemaking industry challenges. S. cerevisiae x S. kudriavzevii hybrids exhibit good fermentative capabilities at low temperatures, and produce wines with smaller alcohol quantities and larger glycerol quantities, which can be very useful to solve challenges in the winemaking industry such as the necessity to enhance the aroma profile. Methods: In this study, we performed a transcriptomic study of S. cerevisiae x S. kudriavzevii hybrids in low temperature winemaking conditions. Results: The results revealed that the hybrids have acquired both fermentative abilities and cold adaptation abilities, attributed to S. cerevisiae and S. kudriavzevii parental species, respectively, showcasing their industrially relevant characteristics. For several key genes, we also studied the contribution to gene expression of each of the alleles of S. cerevisiae and S. kudriavzevii in the S. cerevisiae x S. kudriavzevii hybrids. From the results, it is not clear how important the differential expression of the specific parental alleles is to the phenotype of the hybrids. Conclusions: This study shows that the fermentative abilities of S. cerevisiae x S. kudriavzevii hybrids at low temperatures do not seem to result from differential expression of specific parental alleles of the key genes involved in this phentoype.


2012 ◽  
Vol 446 (3) ◽  
pp. 477-488 ◽  
Author(s):  
Isaac Córcoles-Sáez ◽  
Lídia Ballester-Tomas ◽  
Maria A. de la Torre-Ruiz ◽  
Jose A. Prieto ◽  
Francisca Randez-Gil

Unlike other stresses, the physiological significance and molecular mechanisms involved in the yeast cold response are largely unknown. In the present study, we show that the CWI (cell wall integrity) pathway plays an important role in the growth of Saccharomyces cerevisiae at low temperatures. Cells lacking the Wsc1p (wall integrity and stress response component 1) membrane sensor or the MAPKs (mitogen-activated protein kinases) Bck1p (bypass of C kinase 1), Mkk (Mapk kinase) 1p/Mkk2p or Slt2p (suppressor of lyt2) exhibited cold sensitivity. However, there was no evidence of either a cold-provoked perturbation of the cell wall or a differential cold expression program mediated by Slt2p. The results of the present study suggest that Slt2p is activated by different inputs in response to nutrient signals and mediates growth control through TORC1 (target of rapamycin 1 complex)–Sch9p (suppressor of cdc25) and PKA (protein kinase A) at low temperatures. We found that absence of TOR1 (target of rapamycin 1) causes cold sensitivity, whereas a ras2Δ mutant shows increased cold growth. Lack of Sch9p alleviates the phenotype of slt2Δ and bck1Δ mutant cells, as well as attenuation of PKA activity by overexpression of BCY1 (bypass of cyclase mutations 1). Interestingly, swi4Δ mutant cells display cold sensitivity, but the phenotype is neither mediated by the Slt2p-regulated induction of Swi4p (switching deficient 4)-responsive promoters nor influenced by osmotic stabilization. Hence, cold signalling through the CWI pathway has distinct features and might mediate still unknown effectors and targets.


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