scholarly journals Independent mechanisms for acquired salt tolerance versus growth resumption induced by mild ethanol pretreatment inSaccharomyces cerevisiae

2018 ◽  
Author(s):  
Elizabeth A. McDaniel ◽  
Tara N. Stuecker ◽  
Manasa Veluvolu ◽  
Audrey P. Gasch ◽  
Jeffrey A. Lewis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Salt Tolerance ◽  
Stress Resistance ◽  
Natural Variation ◽  
Lethal Dose ◽  
Cross Protection ◽  
High Salt ◽  
Ethanol Stress ◽  
Ethanol Pretreatment ◽  
Acquired Stress Resistance

ABSTRACTAll living organisms must recognize and respond to various environmental stresses throughout their lifetime. In natural environments, cells frequently encounter fluctuating concentrations of different stressors that can occur in combination or sequentially. Thus, the ability to anticipate an impending stress is likely ecologically relevant. One possible mechanism for anticipating future stress is acquired stress resistance, where cells pre-exposed to a mild sub-lethal dose of stress gain the ability to survive an otherwise lethal dose of stress. We have been leveraging wild strains ofSaccharomyces cerevisiaeto investigate natural variation in the yeast ethanol stress response and its role in acquired stress resistance. Here, we report that a wild vineyard isolate possesses ethanol-induced cross-protection against severe concentrations of salt. Because this phenotype correlates with ethanol-dependent induction of theENAgenes, which encode sodium efflux pumps already associated with salt resistance, we hypothesized that variation inENAexpression was responsible for differences in acquired salt tolerance across strains. Surprisingly, we found that theENAgenes were completely dispensable for ethanol-induced survival of high salt concentrations in the wild vineyard strain. Instead, theENAgenes were necessary for the ability to resume growth on high concentrations of salt following a mild ethanol pretreatment. Surprisingly, this growth acclimation phenotype was also shared by the lab yeast strain despite lack ofENAinduction under this condition. This study underscores that cross protection can affect both viability and growth through distinct mechanisms, both of which likely confer fitness effects that are ecologically relevant.IMPORTANCEMicrobes in nature frequently experience “boom or bust” cycles of environmental stress. Thus, microbes that can anticipate the onset of stress would have an advantage. One way microbes anticipate future stress is through acquired stress resistance, where cells exposed to a mild dose of one stress gain the ability survive an otherwise lethal dose of a subsequent stress. In the budding yeastSaccharomyces cerevisiae,certain stressors can cross protect against high salt concentrations, though the mechanisms governing this acquisition of higher stress resistance are not well understood. In this study, we took advantage of wild yeast strains to understand the mechanism underlying ethanol-induced cross protection against high salt concentrations. We found that mild ethanol stress allows cells to resume growth on high salt, which involves a novel role for a well-studied salt transporter. Overall, this discovery highlights how leveraging natural variation can provide new insights into well-studied stress defense mechanisms.

scholarly journals Independent Mechanisms for Acquired Salt Tolerance versus Growth Resumption Induced by Mild Ethanol Pretreatment inSaccharomyces cerevisiae

mSphere ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Elizabeth A. McDaniel ◽  
Tara N. Stuecker ◽  
Manasa Veluvolu ◽  
Audrey P. Gasch ◽  
Jeffrey A. Lewis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Resistance ◽  
Natural Variation ◽  
Lethal Dose ◽  
Cross Protection ◽  
High Salt ◽  
Ethanol Stress ◽  
Content Type ◽  
Ethanol Pretreatment ◽  
Acquired Stress Resistance

ABSTRACTAll living organisms must recognize and respond to various environmental stresses throughout their lifetime. In natural environments, cells frequently encounter fluctuating concentrations of different stressors that can occur in combination or sequentially. Thus, the ability to anticipate an impending stress is likely ecologically relevant. One possible mechanism for anticipating future stress is acquired stress resistance, where cells preexposed to a mild sublethal dose of stress gain the ability to survive an otherwise lethal dose of stress. We have been leveraging wild strains ofSaccharomyces cerevisiaeto investigate natural variation in the yeast ethanol stress response and its role in acquired stress resistance. Here, we report that a wild vineyard isolate possesses ethanol-induced cross protection against severe concentrations of salt. Because this phenotype correlates with ethanol-dependent induction of theENAgenes, which encode sodium efflux pumps already associated with salt resistance, we hypothesized that variation inENAexpression was responsible for differences in acquired salt tolerance across strains. Surprisingly, we found that theENAgenes were completely dispensable for ethanol-induced survival of high salt concentrations in the wild vineyard strain. Instead, theENAgenes were necessary for the ability to resume growth on high concentrations of salt following a mild ethanol pretreatment. Surprisingly, this growth acclimation phenotype was also shared by the lab yeast strain despite lack ofENAinduction under this condition. This study underscores that cross protection can affect both viability and growth through distinct mechanisms, both of which likely confer fitness effects that are ecologically relevant.IMPORTANCEMicrobes in nature frequently experience “boom or bust” cycles of environmental stress. Thus, microbes that can anticipate the onset of stress would have an advantage. One way that microbes anticipate future stress is through acquired stress resistance, where cells exposed to a mild dose of one stress gain the ability to survive an otherwise lethal dose of a subsequent stress. In the budding yeastSaccharomyces cerevisiae, certain stressors can cross protect against high salt concentrations, though the mechanisms governing this acquired stress resistance are not well understood. In this study, we took advantage of wild yeast strains to understand the mechanism underlying ethanol-induced cross protection against high salt concentrations. We found that mild ethanol stress allows cells to resume growth on high salt, which involves a novel role for a well-studied salt transporter. Overall, this discovery highlights how leveraging natural variation can provide new insights into well-studied stress defense mechanisms.

scholarly journals Linkage mapping of yeast cross protection connects gene expression variation to a higher-order organismal trait

2017 ◽  
Author(s):  
Tara N. Stuecker ◽  
Amanda N. Scholes ◽  
Jeffrey A. Lewis
Keyword(s):  
Gene Expression ◽  
Natural Variation ◽  
Higher Order ◽  
Cross Protection ◽  
Ethanol Stress ◽  
Gene Expression Variation ◽  
Gene Expression Response ◽  
Expression Variation ◽  
Wild Strains ◽  
Stress Defense

AbstractGene expression variation is extensive in nature, and is hypothesized to play a major role in shaping phenotypic diversity. However, connecting differences in gene expression across individuals to higher-order organismal traits is not trivial. In many cases, gene expression variation may be evolutionarily neutral, and in other cases expression variation may only affect phenotype under specific conditions. To understand connections between gene expression variation and stress defense phenotypes, we have been leveraging extensive natural variation in the gene expression response to acute ethanol in laboratory and wild Saccharomyces cerevisiae strains. Previous work found that the genetic architecture underlying these expression differences included dozens of “hotspot” loci that affected many transcripts in trans. In the present study, we provide new evidence that one of these expression QTL hotspot loci is responsible for natural variation in one particular stress defense phenotype—ethanol-induced cross protection against severe doses of H2O2. The causative polymorphism is in the heme-activated transcription factor Hap1p, which we show directly impacts cross protection, but not the basal H2O2 resistance of unstressed cells. This provides further support that distinct cellular mechanisms underlie basal and acquired stress resistance. We also show that the Hap1p-dependent cross protection relies on novel regulation of cytosolic catalase T (Ctt1p) during ethanol stress in wild strains. Because ethanol accumulation precedes aerobic respiration and accompanying reactive oxygen species formation, wild strains with the ability to anticipate impending oxidative stress would likely be at an advantage. This study highlights how strategically chosen traits that better correlate with gene expression changes can improve our power to identify novel connections between gene expression variation and higher-order organismal phenotypes.

scholarly journals Acquired Resistance to Severe Ethanol Stress on Protein Quality Control in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Masashi Yoshida ◽  
Sae Kato ◽  
Shizu Fukuda ◽  
Shingo Izawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Resistance ◽  
Ethanol Tolerance ◽  
Protein Quality ◽  
Yeast Cells ◽  
Ethanol Stress ◽  
Mild Stress ◽  
Insoluble Protein ◽  
Protein Levels ◽  
Brewing Process

Acute severe ethanol stress (10% v/v) damages proteins and causes the intracellular accumulation of insoluble proteins in Saccharomyces cerevisiae. On the other hand, a pretreatment with mild stress increases tolerance to subsequent severe stress, which is called acquired stress resistance. It currently remains unclear whether the accumulation of insoluble proteins under severe ethanol stress may be mitigated by increasing protein quality control (PQC) activity in cells pretreated with mild stress. In the present study, we examined the induction of resistance to severe ethanol stress in PQC, and confirmed that a pretreatment with 6% (v/v) ethanol or mild thermal stress at 37°C significantly reduced insoluble protein levels and the aggregation of Lsg1, which is prone to denaturation and aggregation by stress, in yeast cells under 10% (v/v) ethanol stress. The induction of this stress resistance required the new synthesis of proteins; the expression of proteins comprising the bi-chaperone system (Hsp104, Ssa3, and Fes1), Sis1, and Hsp42 was up-regulated during the pretreatment and maintained under subsequent severe ethanol stress. Since the pretreated cells of deficient mutants in the bi-chaperone system (fes1Δhsp104Δ and ssa2Δssa3Δssa4Δ) failed to sufficiently reduce insoluble protein levels and Lsg1 aggregation, the enhanced activity of the bi-chaperone system appears to be important for the induction of adequate stress resistance. In contrast, the importance of proteasomes and aggregases (Btn2 and Hsp42) in the induction of stress resistance has not been confirmed. These results provide further insights into the PQC activity of yeast cells under severe ethanol stress, including the brewing process. IMPORTANCE Although the budding yeast S. cerevisiae, which is used in the production of alcoholic beverages and bioethanol, is highly tolerant of ethanol, high concentrations of ethanol are also stressful to the yeast and cause various adverse effects, including protein denaturation. A pretreatment with mild stress improves the ethanol tolerance of yeast cells; however, it currently remains unclear whether it increases PQC activity and reduces the levels of denatured proteins. In the present study, we found that a pre-treatment with mild ethanol up-regulated the expression of proteins involved in PQC and mitigated the accumulation of insoluble proteins, even under severe ethanol stress. These results provide novel insights into ethanol tolerance and the adaptive capacity of yeast. They may also contribute to research on the physiology of yeast cells during the brewing process, in which the concentration of ethanol gradually increases.

scholarly journals Salinity Effects on Gene Expression, Morphological, and Physio-Biochemical Responses of Stevia rebaudiana Bertoni In Vitro

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 820
Author(s):  
Clara Azzam ◽  
Sudad Al-Taweel ◽  
Ranya Abdel-Aziz ◽  
Karim Rabea ◽  
Alaa Abou-Sreea ◽  
...  
Keyword(s):  
Salt Tolerance ◽  
Biochemical Parameters ◽  
Large Scale ◽  
Stevia Rebaudiana ◽  
Multiple Shoots ◽  
High Salt ◽  
Stress Factors ◽  
Stevia Rebaudiana Bertoni ◽  
Nacl Concentration

Stevia rebaudiana Bertoni is a little bush, which is cultivated on a large scale in many countries for medicinal purposes and used as a natural sweetener in food products. The present work aims to conduct a protocol for stevia propagation in vitro to produce and introduce Stevia rebaudiana plants as a new sweetener crop to Egyptian agriculture. To efficiently maximize its propagation, it is important to study the influence of stress factors on the growth and development of Stevia rebaudiana grown in vitro. Two stevia varieties were investigated (Sugar High A3 and Spanti) against salt stress. Leaves were used as the source of explants for callus initiation, regeneration, multiplication and rooting. Some stress-related traits, i.e., photosynthetic pigments, proline contents, and enzyme activity for peroxidase (POD), polyphenol oxidase (PPO), and malate dehydrogenase (MDH) were studied. Murashig and Skoog (MS) medium was supplemented with four NaCl concentrations: 500, 1000, 2000, and 3000 mgL−1, while a salt-free medium was used as the control. The data revealed that salinity negatively affected all studied characters: the number of surviving calli, regeneration%, shoot length, the number of multiple shoots, number of leaf plantlets−1, number of root plantlets−1, and root length. The data also revealed that Sugar High A3 is more tolerant than Spanti. The total chlorophyll content decreased gradually with increasing NaCl concentration. However, the opposite was true for proline content. Isozyme’s fractionation exhibited high levels of variability among the two varieties. Various biochemical parameters associated with salt tolerance were detected in POD. Namely, POD4, POD6, POD 9 at an Rf of 0.34, 0.57, and 0.91 in the Sugar High A3 variety under high salt concentration conditions, as well as POD 10 at an Rf of 0.98 in both varieties under high salt concentrations. In addition, the overexpression of POD 5 and POD 10 at Rf 0.52 and 0.83 was found in both varieties at high NaCl concentrations. Biochemical parameters associated with salt tolerance were detected in PPO (PPO1, PPO2 and PPO4 at an Rf of 0.38, 0.42 and 0.62 in the Sugar High A3 variety under high salt concentrations) and MDH (MDH 3 at an Rf of 0.40 in both varieties at high salt concentrations). Therefore, these could be considered as important biochemical markers associated with salt tolerance and could be applied in stevia breeding programs (marker-assisted selection). This investigation recommends stevia variety Sugar High A3 to be cultivated under salt conditions.

scholarly journals VTC4 Polyphosphate Polymerase Knockout Increases Stress Resistance of Saccharomyces cerevisiae Cells

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 487
Author(s):  
Alexander Tomashevsky ◽  
Ekaterina Kulakovskaya ◽  
Ludmila Trilisenko ◽  
Ivan V. Kulakovskiy ◽  
Tatiana Kulakovskaya ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heavy Metal ◽  
Stress Response ◽  
Stress Resistance ◽  
Alkaline Stress ◽  
Inorganic Polyphosphate ◽  
Divalent Metal Transporter ◽  
Metal Transporter ◽  
Elevated Expression ◽  
Chaperone Complex

Inorganic polyphosphate (polyP) is an important factor of alkaline, heavy metal, and oxidative stress resistance in microbial cells. In yeast, polyP is synthesized by Vtc4, a subunit of the vacuole transporter chaperone complex. Here, we report reduced but reliably detectable amounts of acid-soluble and acid-insoluble polyPs in the Δvtc4 strain of Saccharomyces cerevisiae, reaching 10% and 20% of the respective levels of the wild-type strain. The Δvtc4 strain has decreased resistance to alkaline stress but, unexpectedly, increased resistance to oxidation and heavy metal excess. We suggest that increased resistance is achieved through elevated expression of DDR2, which is implicated in stress response, and reduced expression of PHO84 encoding a phosphate and divalent metal transporter. The decreased Mg2+-dependent phosphate accumulation in Δvtc4 cells is consistent with reduced expression of PHO84. We discuss a possible role that polyP level plays in cellular signaling of stress response mobilization in yeast.

Osmotic Shock Augments Ethanol Stress in Saccharomyces cerevisiae MTCC 2918

2011 ◽  
Vol 64 (2) ◽  
pp. 100-105 ◽  
Author(s):  
Geraldine S. M. John ◽  
Murugesan Gayathiri ◽  
Chellan Rose ◽  
Asit B. Mandal
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Osmotic Shock ◽  
Ethanol Stress

scholarly journals The full-length transcriptome of Spartina alterniflora reveals the complexity of high salt tolerance in monocotyledonous halophyte

2019 ◽  
Author(s):  
Wenbin Ye ◽  
Taotao Wang ◽  
Wei Wei ◽  
Shuaitong Lou ◽  
Faxiu Lan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salt Stress ◽  
Alternative Splicing ◽  
Salt Tolerance ◽  
Protein Kinases ◽  
Spartina Alterniflora ◽  
High Salt ◽  
Full Length ◽  
Salt Tolerant ◽  
High Salt Tolerance

ABSTRACTSpartina alterniflora (Spartina) is the only halophyte in the salt marsh. However, the molecular basis of its high salt tolerance remains elusive. In this study, we used PacBio full-length single molecule long-read sequencing and RNA-seq to elucidate the transcriptome dynamics of high salt tolerance in Spartina by salt-gradient experiments (0, 350, 500 and 800 mM NaCl). We systematically analyzed the gene expression diversity and deciphered possible roles of ion transporters, protein kinases and photosynthesis in salt tolerance. Moreover, the co-expression network analysis revealed several hub genes in salt stress regulatory networks, including protein kinases such as SaOST1, SaCIPK10 and three SaLRRs. Furthermore, high salt stress affected the gene expression of photosynthesis through down-regulation at the transcription level and alternative splicing at the post-transcriptional level. In addition, overexpression of two Spartina salt-tolerant genes SaHSP70-I and SaAF2 in Arabidopsis significantly promoted the salt tolerance of transgenic lines. Finally, we built the SAPacBio website for visualizing the full-length transcriptome sequences, transcription factors, ncRNAs, salt-tolerant genes, and alternative splicing events in Spartina. Overall, this study sheds light on the high salt tolerance mechanisms of monocotyledonous-halophyte and demonstrates the potential of Spartina genes for engineering salt-tolerant plants.

scholarly journals Acute ethanol stress induces sumoylation of conserved chromatin structural proteins in Saccharomyces cerevisiae

2021 ◽  
pp. mbc.E20-11-0715
Author(s):  
Amanda I. Bradley ◽  
Nicole M. Marsh ◽  
Heather R. Borror ◽  
Kaitlyn E. Mostoller ◽  
Amber I. Gama ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Exposure ◽  
S Phase ◽  
Structural Proteins ◽  
Ethanol Stress ◽  
Post Translational Modification ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cycle Arrest ◽  
Chromatin Structural ◽  
Acute Ethanol

Stress is ubiquitous to life and can irreparably damage essential biomolecules and organelles in cells. To survive, organisms must sense and adapt to stressful conditions. One highly conserved adaptive stress response is through the post-translational modification of proteins by the small ubiquitin-like modifier (SUMO). Here, we examine the effects of acute ethanol stress on protein sumoylation in the budding yeast Saccharomyces cerevisiae . We found that cells exhibit a transient sumoylation response after acute exposure to ≤ 7.5% ethanol. By contrast, the sumoylation response becomes chronic at 10% ethanol exposure. Mass spectrometry analyses identified 18 proteins that are sumoylated after acute ethanol exposure, with 15 known to associate with chromatin. Upon further analysis, we found that the chromatin structural proteins Smc5 and Smc6 undergo ethanol-induced sumoylation that depends on the activity of the E3 SUMO ligase Mms21. Using cell-cycle arrest assays, we observed that Smc5 and Smc6 ethanol-induced sumoylation occurs during G1 and G2/M phases but not S phase. Acute ethanol exposure also resulted in the formation of Rad52 foci at levels comparable to Rad52 foci formation after exposure to the DNA alkylating agent methyl methanesulfonate (MMS). MMS exposure is known to induce the intra-S phase DNA damage checkpoint via Rad53 phosphorylation, but ethanol exposure did not induce Rad53 phosphorylation. Ethanol abrogated the effect of MMS on Rad53 phosphorylation when added simultaneously. From these studies, we propose that acute ethanol exposure induces a change in chromatin leading to sumoylation of specific chromatin-structural proteins.

Sign in / Sign up

Export Citation Format

Share Document