Complementing DIGE proteomics and DNA subarray analyses to shed light on Oenococcus oeni adaptation to ethanol in wine-simulated conditions.
Direct addition of Oenococcus oeni starters into wine can cause viability problems. In the present study, the influence of ethanol in wine-simulated conditions on O. oeni has been evaluated by complementing microarray techniques and DIGE proteomics. Two different ethanol concentrations were studied. In 12% ethanol, pyrimidine anabolism was stimulated, but in 8% ethanol some energy-consuming biosynthetic pathways were limited. The most significant result was the stress response induced by alcohol that concerned both the cell-envelope and specific stress proteins. Interestingly, 8% and 12% ethanol triggered different stress responses: in mild ethanol stress (8%), chaperones with prevalent refolding activity (like HSP20) were over-expressed, whereas at higher alcohol concentration (12%), together with HSP20 and the refolding DNAJ/K, also chaperones having proteolytic activity (like ClpP) were induced. Furthermore the stress response repressor HrcA was downregulated only at 12% ethanol, suggesting that it controls stress pathways, which are different from those active at 8% alcohol. This result confirms that the HrcA system is operative in O. oeni where the CtrS system is prevalent.


CONCLUSIONS
The use of malolactic starter cultures has become widespread to control the MLF process and to prevent off-flavors. There is significant interest in understanding the molecular mechanisms that O. oeni uses to adapt to harsh wine conditions. The overall results highlight that the alcohol-induced stress response involves not only biosynthesis of stress proteins but also envelope-linked mechanisms. From a practical point of view this research underlines the importance of starters acclimation to induce responses that would allow better adaptation to the wine. As a consequence, a well adapted starter can complete malolactic fermentation and improve the final wine quality.
Consiglio per la ricerca e la sperimentazione in agricoltura, Centro di ricerca per l'enologia, Via P. Micca 35, 14100 Asti, Italy; Università di Torino, Department of Agricultural, Forest and Food Sciences, Largo Paolo Braccini 2, Grugliasco, 10095 Torino, Italy; Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kgs. Lyngby, Denmark.
Antonella
A
Costantini
Università di Torino, Department of Agricultural, Forest and Food Sciences, Largo Paolo Braccini 2, Grugliasco, 10095 Torino, Italy.
Kalliopi
K
Rantsiou
Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kgs. Lyngby, Denmark.
Avishek
A
Majumder
Consiglio per la ricerca e la sperimentazione in agricoltura, Centro di ricerca per l'enologia, Via P. Micca 35, 14100 Asti, Italy.
Susanne
S
Jacobsen
Università di Torino, Department of Life Sciences and Systems Biology, Via Accademia Albertina 13, 10123 Torino, Italy.
Enrica
E
Pessione
Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kgs. Lyngby, Denmark.
Birte
B
Svensson
Consiglio per la ricerca e la sperimentazione in agricoltura, Centro di ricerca per l'enologia, Via P. Micca 35, 14100 Asti, Italy.
Emilia
E
Garcia-Moruno
Università di Torino, Department of Agricultural, Forest and Food Sciences, Largo Paolo Braccini 2, Grugliasco, 10095 Torino, Italy. Electronic address: lucasimone.cocolin@unito.it.
Luca
L
Cocolin
D002462:Cell Membrane / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D058645:Denaturing Gradient Gel Electrophoresis; D000431:Ethanol / Q000737:chemistry*; D005285:Fermentation; D050886:HSP20 Heat-Shock Proteins / Q000378:metabolism; D008293:Malates / Q000378:metabolism; D013058:Mass Spectrometry; D018832:Molecular Chaperones / Q000378:metabolism; D056585:Oenococcus / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D040081:Protein Array Analysis; D011489:Protein Denaturation; D017510:Protein Folding; D059748:Proteolysis; D020543:Proteome; D040901:Proteomics / Q000379:methods*; D059467:Transcriptome; D014920:Wine
D050886:HSP20 Heat-Shock Proteins; D008293:Malates; D018832:Molecular Chaperones; D020543:Proteome; D000431:Ethanol
Cell envelope; Chaperones; EPS; Energy metabolism; O. oeni; Stress response