ABSTRACT: In a previous study, we identified extensive natural variation in the response to acute ethanol treatment in three yeast strains: a lab strain derived from the commonly used S288c (DBY8268), vineyard isolate M22, and oak soil strain YPS163. Many expression differences persisted across several modules of co-regulated genes, implicating trans-acting systemic differences in ethanol sensing and/or response. To understand the genetic basis for these expression differences, we performed eQTL mapping analysis of the response to acute ethanol stress in ~100 F2 strains from two crosses: DBY8268x M22 and DBY8268 x YPS163.
Project description:In a previous study, we identified extensive natural variation in the response to acute ethanol treatment in three yeast strains: a lab strain derived from the commonly used S288c (DBY8268), vineyard isolate M22, and oak soil strain YPS163. Many expression differences persisted across several modules of co-regulated genes, implicating trans-acting systemic differences in ethanol sensing and/or response. To understand the genetic basis for these expression differences, we performed eQTL mapping analysis of the response to acute ethanol stress in ~100 F2 strains from two crosses: DBY8268x M22 and DBY8268 x YPS163. We measured the gene expression response to acute ethanol stress (5% for 30 min) in 6 replicates for the parental strains, and in biological duplicate for the eQTL mapping population. Dye swaps were performed in the replicates to control for dye-specific effects.
Project description:An S288c-derived lab strain of Saccharomyces cerevisiae has lower ethanol resistance than either the vineyard strain M22 or the oak strain YPS163. We performed a 60 minute time-course experiment in the presence of 5% ethanol and compared the transcriptional response to ethanol between strains. We additionally analyzed the time-point of maximal response (30 min.) in wild type cells, YPS163 msn2D, and YPS163 hap1D cells.
Project description:An S288c-derived lab strain of Saccharomyces cerevisiae has lower ethanol resistance than either the vineyard strain M22 or the oak strain YPS163. We performed a 60 minute time-course experiment in the presence of 5% ethanol and compared the transcriptional response to ethanol between strains. We additionally analyzed the time-point of maximal response (30 min.) in wild type cells, YPS163 msn2D, and YPS163 hap1D cells. The genomic expression response to 5% ethanol stress was measured in 3 different strain backgrounds, and 2 different mutant backgrounds. Basal gene expression was also compared in two non-lab strains to the S288c reference. A single replicate was performed for the time-course experiment. All of the single time-point experiments were performed using biological triplicates.
Project description:The Crabtree effect, in which fermentative metabolism is preferred at the expense of respiration, is a hallmark of budding yeast’s glucose response and a model for the Warburg effect in human tumors. While the glucose-responsive transcriptional repressors Mig1p and Mig2p play well-characterized roles in the Crabtree effect, little function for the related Mig3p transcription factor has been uncovered despite numerous investigations of laboratory yeast strains. Here we studied a wild isolate of Saccharomyces cerevisiae to uncover a critical role for Mig3p that has been lost in S288c-derived laboratory strains. We found that Mig3p affects the expression of hundreds of glucose-responsive genes in the oak strain YPS163, both during growth under standard conditions and upon ethanol treatment. Our results suggest that Mig3p may act as a multifunctional activator/repressor that plays separate roles under standard versus stress conditions, but this function has been largely lost in the lab strains. Population analysis suggests that the lab strain, and several wild strains, harbor mutations that diminish Mig3p function. Thus, by expanding our attention to multiple genetic backgrounds, we have uncovered an important missing link in a key metabolic response.
Project description:The Crabtree effect, in which fermentative metabolism is preferred at the expense of respiration, is a hallmark of budding yeast’s glucose response and a model for the Warburg effect in human tumors. While the glucose-responsive transcriptional repressors Mig1p and Mig2p play well-characterized roles in the Crabtree effect, little function for the related Mig3p transcription factor has been uncovered despite numerous investigations of laboratory yeast strains. Here we studied a wild isolate of Saccharomyces cerevisiae to uncover a critical role for Mig3p that has been lost in S288c-derived laboratory strains. We found that Mig3p affects the expression of hundreds of glucose-responsive genes in the oak strain YPS163, both during growth under standard conditions and upon ethanol treatment. Our results suggest that Mig3p may act as a multifunctional activator/repressor that plays separate roles under standard versus stress conditions, but this function has been largely lost in the lab strains. Population analysis suggests that the lab strain, and several wild strains, harbor mutations that diminish Mig3p function. Thus, by expanding our attention to multiple genetic backgrounds, we have uncovered an important missing link in a key metabolic response. We performed a series of microarray experiments comparing the gene expression response of unstressed or EtOH stressed wild-type or mig3∆ strains in either the BY4741 or YPS163 background (biological triplicates). We also compared gene expression for in reciprocal hemizygous strains (YPS163/BY4741mig3∆ and YPS163mig3∆/BY4742; biological duplicates). Lastly, we measured the gene expression of BY4741 over-expressing BY_MIG3 via galactose induction (biological triplicates).
Project description:Here we report the massively parallel cDNA sequencing (RNA-seq) analysis performed using high throughput sequencing of four vineyard yeast strains collected from the vineyards of the “Prosecco di Conegliano-Valdobbiadene” (P283 and P301 strains) and Piave AO (Appellation of origin) (R008 and R103 strains) regions in North East of Italy. Results were compared with RNA-seq performed on a commercial yeast strain (EC1118) and a laboratory strain (S288c). Yeast cells were collected at two different steps of the fermentation curve: at the beginning of the process, when the CO2 produced by the cells was 6 g/l (middle exponential growth phase), and in the middle of fermentation, at 45 g/l (early stationary phase). Three biological replicates of the fermentations were performed for each strain and samples for RNA-seq were gathered at the beginning of the process. The aim of this experiment was the comparison of the transcriptomes of the six yeast strains to identify the genes characterizing wild type yeast isolates, "commercial" and laboratory strains.
Project description:The environmental stresses and inhibitors encounted by Saccharomyces cerevisiae strains are main limiting factors in bioethanol fermentation. Investigation of the molecular mechanisms underlying the stresses-related phenotypes diversities within and between S. cerevisiae populations could guide the construction of yeast strains with improved stresses tolerance and fermentation performances. Here, we explored the genetic characteristics of the bioethanol S. cerevisiae strains, and elucidated the genetic variations correlated with its advantaged traits (higher ethanol yield under sever conditions and better tolerance to multiple stresses compared to an S288c derived laboratory strain BYZ1). Firstly, pulse-field gel electrophoresis combined with array-comparative genomic hybridization was used to compare the genome structure of industrial strains and the laboratory strain BYZ1.
Project description:Distilled spirits production using S. cerevisiae requires understanding the mechanisms of yeast cell response to the alcohol stress. Reportedly, specific mutations in genes of the ubiquitin-proteasome system, e.g. RPN4, may result in strains exhibiting either hyper-resistance or increased sensitivity to different alcohols. In this work, we studied Rpn4-dependent response of different yeast strains to short-term ethanol exposure. Three S. cerevisiae strains were used: wild-type (WT), mutant strain with RPN4 gene deletion (rpn4-delta), and mutant strain with decreased proteasome activity due to PRE1 deregulation (YPL). The resistance tests demonstrated an increased sensitivity of mutant strains to ethanol compared with WT. Comparative proteomics analysis revealed significant differences in molecular responses to ethanol between different strains. GO analysis of proteins upregulated in WT showed enrichments represented by oxidative and heat responses, protein folding/unfolding and protein degradation. Enrichment of at least one of these responses was not observed in mutant strains. At the same time, trehalose synthesis and accumulation of stress granules were enhanced in the mutant strains. We suggest that these pathways could partially compensate for the failure of ubiquitin-proteasome system to cope with the ethanol stress. Also, we suggest impaired compensatory activation of autophagic degradation system in rpn4-delta strain and propose that Rpn4 can be a regulator for autophagy upon ethanol stress. These findings can be a basis for creating genetically modified yeast strains resistant to high levels of alcohol, being further used for fermentation in ethanol production.
Project description:Gene expression variation was measured in 17 non-laboratory strains compared to the sequenced S288c lab strain Keywords: Gene expression comparisons in different yeast strains