Transcriptome analysis of acetic-acid-treated yeast cells identifies a large set of genes whose overexpression or deletion enhances acetic acid tolerance

2015 ◽  
Vol 99 (15) ◽  
pp. 6391-6403 ◽  
Author(s):  
Yeji Lee ◽  
Olviyani Nasution ◽  
Eunyong Choi ◽  
In-Geol Choi ◽  
Wankee Kim ◽  
...  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yanfei Cheng ◽  
Hui Zhu ◽  
Zhengda Du ◽  
Xuena Guo ◽  
Chenyao Zhou ◽  
...  

Abstract Background Saccharomyces cerevisiae is well-known as an ideal model system for basic research and important industrial microorganism for biotechnological applications. Acetic acid is an important growth inhibitor that has deleterious effects on both the growth and fermentation performance of yeast cells. Comprehensive understanding of the mechanisms underlying S. cerevisiae adaptive response to acetic acid is always a focus and indispensable for development of robust industrial strains. eIF5A is a specific translation factor that is especially required for the formation of peptide bond between certain residues including proline regarded as poor substrates for slow peptide bond formation. Decrease of eIF5A activity resulted in temperature-sensitive phenotype of yeast, while up-regulation of eIF5A protected transgenic Arabidopsis against high temperature, oxidative or osmotic stress. However, the exact roles and functional mechanisms of eIF5A in stress response are as yet largely unknown. Results In this research, we compared cell growth between the eIF5A overexpressing and the control S. cerevisiae strains under various stressed conditions. Improvement of acetic acid tolerance by enhanced eIF5A activity was observed all in spot assay, growth profiles and survival assay. eIF5A prompts the synthesis of Ume6p, a pleiotropic transcriptional factor containing polyproline motifs, mainly in a translational related way. As a consequence, BEM4, BUD21 and IME4, the direct targets of Ume6p, were up-regulated in eIF5A overexpressing strain, especially under acetic acid stress. Overexpression of UME6 results in similar profiles of cell growth and target genes transcription to eIF5A overexpression, confirming the role of Ume6p and its association between eIF5A and acetic acid tolerance. Conclusion Translation factor eIF5A protects yeast cells against acetic acid challenge by the eIF5A-Ume6p-Bud21p/Ime4p/Bem4p axles, which provides new insights into the molecular mechanisms underlying the adaptive response and tolerance to acetic acid in S. cerevisiae and novel targets for construction of robust industrial strains.


2016 ◽  
Vol 473 (23) ◽  
pp. 4311-4325 ◽  
Author(s):  
Joana F. Guerreiro ◽  
Alexander Muir ◽  
Subramaniam Ramachandran ◽  
Jeremy Thorner ◽  
Isabel Sá-Correia

Acetic acid-induced inhibition of yeast growth and metabolism limits the productivity of industrial fermentation processes, especially when lignocellulosic hydrolysates are used as feedstock in industrial biotechnology. Tolerance to acetic acid of food spoilage yeasts is also a problem in the preservation of acidic foods and beverages. Thus understanding the molecular mechanisms underlying adaptation and tolerance to acetic acid stress is increasingly important in industrial biotechnology and the food industry. Prior genetic screens for Saccharomyces cerevisiae mutants with increased sensitivity to acetic acid identified loss-of-function mutations in the YPK1 gene, which encodes a protein kinase activated by the target of rapamycin (TOR) complex 2 (TORC2). We show in the present study by several independent criteria that TORC2–Ypk1 signaling is stimulated in response to acetic acid stress. Moreover, we demonstrate that TORC2-mediated Ypk1 phosphorylation and activation is necessary for acetic acid tolerance, and occurs independently of Hrk1, a protein kinase previously implicated in the cellular response to acetic acid. In addition, we show that TORC2–Ypk1-mediated activation of l-serine:palmitoyl-CoA acyltransferase, the enzyme complex that catalyzes the first committed step of sphingolipid biosynthesis, is required for acetic acid tolerance. Furthermore, analysis of the sphingolipid pathway using inhibitors and mutants indicates that it is production of certain complex sphingolipids that contributes to conferring acetic acid tolerance. Consistent with that conclusion, promoting sphingolipid synthesis by adding exogenous long-chain base precursor phytosphingosine to the growth medium enhanced acetic acid tolerance. Thus appropriate modulation of the TORC2–Ypk1–sphingolipid axis in industrial yeast strains may have utility in improving fermentations of acetic acid-containing feedstocks.


2016 ◽  
Vol 82 (15) ◽  
pp. 4673-4681 ◽  
Author(s):  
Claudia Capusoni ◽  
Stefania Arioli ◽  
Paolo Zambelli ◽  
M. Moktaduzzaman ◽  
Diego Mora ◽  
...  

ABSTRACTThe yeastDekkera bruxellensis, associated with wine and beer production, has recently received attention, because its high ethanol and acid tolerance enables it to compete withSaccharomyces cerevisiaein distilleries that produce fuel ethanol. We investigated how different cultivation conditions affect the acetic acid tolerance ofD. bruxellensis. We analyzed the ability of two strains (CBS 98 and CBS 4482) exhibiting different degrees of tolerance to grow in the presence of acetic acid under aerobic and oxygen-limited conditions. We found that the concomitant presence of acetic acid and oxygen had a negative effect onD. bruxellensisgrowth. In contrast, incubation under oxygen-limited conditions resulted in reproducible growth kinetics that exhibited a shorter adaptive phase and higher growth rates than those with cultivation under aerobic conditions. This positive effect was more pronounced in CBS 98, the more-sensitive strain. Cultivation of CBS 98 cells under oxygen-limited conditions improved their ability to restore their intracellular pH upon acetic acid exposure and to reduce the oxidative damage to intracellular macromolecules caused by the presence of acetic acid. This study reveals an important role of oxidative stress in acetic acid tolerance inD. bruxellensis, indicating that reduced oxygen availability can protect against the damage caused by the presence of acetic acid. This aspect is important for optimizing industrial processes performed in the presence of acetic acid.IMPORTANCEThis study reveals an important role of oxidative stress in acetic acid tolerance inD. bruxellensis, indicating that reduced oxygen availability can have a protective role against the damage caused by the presence of acetic acid. This aspect is important for the optimization of industrial processes performed in the presence of acetic acid.


2016 ◽  
Vol 9 (1) ◽  
Author(s):  
Daniel González-Ramos ◽  
Arthur R. Gorter de Vries ◽  
Sietske S. Grijseels ◽  
Margo C. van Berkum ◽  
Steve Swinnen ◽  
...  

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