Œnococcus oeni is a wine-associated lactic acid bacterium performs the malolactic fermentation, which improves the taste and aromatic complexity of many wine. Although, wine exhibits harsh and challenging conditions (low pH, low temperature, nutrient-poor and presence of ethanol), O. oeni possesses a remarkable adaptability to those physiochemical conditions.
Mechanisms for responding to environmental changes are universally present in living beings and are essential for coping with the stress and for adapting to the new conditions. O. oeni tolerance to low pH and ethanol make its an interesting bacteria model for investigating stress response mechanism in lactic acid bacteria. However, lack of appropriate techniques to manipulate O. oeni genome has long delay molecular study of this fastidious bacterium. To get around the lack of genetic tool for gene replacement, we focused our work on gene inactivation by using antisense RNA approach to modulate gene expression. With the goal to understanding the function of O. oeni hsp genes in vivo, we produce antisense RNA targeting genes encoding: a small Hsp (hsp18)1, the master regulator of stress response (ctsR)2 and two caseinolytic protease L members of the HSP100 chaperone family (clpL1, clpL2). Thereby, we highlighted that in vivo inhibition of the expression of some of these genes strongly affects the survival of O. oeni in stress conditions.
This study presents an elegant approach providing access to an in vivo study of gene function in O. oeni.
1. Darsonval, M., Msadek, T., Alexandre, H. & Grandvalet, C. The Antisense RNA Approach: a New Application for In Vivo Investigation of the Stress Response of Oenococcus oeni, a Wine-Associated Lactic Acid Bacterium. Appl. Environ. Microbiol. 82, 18–26 (2016).
2. Darsonval, M., Julliat, F., Msadek, T., Alexandre, H. & Grandvalet, C. CtsR, the Master Regulator of Stress-Response in Oenococcus oeni, Is a Heat Sensor Interacting With ClpL1. Front Microbiol 9, (2018).
Authors: Cosette Grandvalet, Frédérique Julliat, Maud Darsonval, Tarek Msadek, Hervé Alexandre
UMR A 02.102 Procédés Alimentaires et Microbiologiques, AgroSup Dijon – Université de Bourgogne Franche-Comté, Dijon, FRANCE.
Unité de Biologie des Bactéries Pathogènes àGram Positif, Institut Pasteur, Paris, FRANCE.
CNRS ERL 6002, Paris, FRANCE.
Keywords: Oenococcus oeni, lactic acid bacteria, antisense RNA , stress response