Transcriptomic and Proteomic Analysis of Oenococcus oeni Adaptation to Wine Stress Conditions

Abstract

Oenococcus oeni, the main lactic acid bacteria responsible for malolactic fermentation in wine, has to adapt to stressful conditions, such as low pH and high ethanol content. In this study, the changes in the transcriptome and the proteome of O. oeni PSU-1 during the adaptation period before MLF start have been studied. DNA microarrays were used for the transcriptomic analysis and two complementary proteomic techniques, 2-D DIGE and iTRAQ labeling were used to analyze the proteomic response. One of the most influenced functions in PSU-1 due to inoculation into wine-like medium (WLM) was translation, showing the over-expression of certain ribosomal genes and the corresponding proteins. Amino acid metabolism and transport was also altered and several peptidases were up regulated both at gene and protein level. Certain proteins involved in glutamine and glutamate metabolism showed an increased abundance revealing the key role of nitrogen uptake under stressful conditions. A strong transcriptional inhibition of carbohydrate metabolism related genes was observed. On the other hand, the transcriptional up-regulation of malate transport and citrate consumption was indicative of the use of L-malate and citrate associated to stress response and as an alternative energy source to sugar metabolism. Regarding the stress mechanisms, our results support the relevance of the thioredoxin and glutathione systems in the adaptation of O. oeni to wine related stress. Genes and proteins related to cell wall showed also significant changes indicating the relevance of the cell envelop as protective barrier to environmental stress. The differences found between transcriptomic and proteomic data suggested the relevance of post-transcriptional mechanisms and the complexity of the stress response in O. oeni adaptation. Further research should deepen into the metabolisms mostly altered due to wine conditions to elucidate the role of each mechanism in the O. oeni ability to develop MLF.

Organic Acid Metabolism and the Impact of Fermentation Practices on Wine Acidity: A Review

“…Efforts have been made in recent years to investigate gene expression profiles during vinification. The detailed analysis of subsets of genes, transcriptional regulation and gene expression profiles in yeast under winemaking conditions has been the focus of several studies (Puig & Perez, 2000;Rossignol et al, 2006;Rossouw et al, 2008;Margalef-Català et al, 2016).…”

Ethanol stress in Oenococcus oeni : transcriptional response and complex physiological mechanisms

“…; Margalef‐Català et al . ), thus allowing ATP synthesis and the deacidification of intracellular and extracellular media. Thanks to the genome sequence of O. oeni PSU‐1 it has been possible to investigate the genes involved in this pathway and their level of transcription under different growth conditions (Augagneur et al .…”

Transcriptomic Analysis of Oenococcus oeni SD-2a Response to Acid Shock by RNA-Seq

“…and metabolic pathways (amino acid transport and metabolism, malate, and citrate metabolism, etc.) (Margalef-Català et al, 2016 ). Nevertheless, there are still some disadvantages of these techniques, for example, non-specific cross-hybridization usually cause a high background level which limits the detection range, the transcripts can be detected only with high copy number, and the total coverage of the transcripts are almost unknown (Liu et al, 2015 ).…”

“…Several works were done on stress mechanisms in O.oeni in wine-like medium /wine /microvinification etc. (Olguin et al, 2015 ; Margalef-Català et al, 2016 ). The originality, in this case, is the use of RNA-seq to investigate low pH response in O.oeni .…”

“…The transcriptome of O. oeni has been studied and quantified via traditional approaches, like hybridization, fingerprinting, and tilling microarrays (Marques et al, 2012 ; Olguin et al, 2015 ; Margalef-Català et al, 2016 ). According to the transcriptomics and proteome results, the mechanism of stress response in O. oeni is believed very complicated, which involves series of proteins (GroEL, GroES, etc.…”