Stress tolerance and transcriptomic response analysis of Yersinia enterocolitica adapted to Origanum vulgare L. essential oil

Abstract

The adaptability of foodborne pathogens to sublethal concentrations of antimicrobials including essential oils poses a great threat to food safety. The aim of this study was to evaluate the effect of pre-exposure of Origanum vulgare L. essential oil (OVEO) on the tolerance of Yersinia enterocolitica and explore its adaptive response mechanism by the RNA-Seq. Our data showed that the OVEO induced the direct-tolerance to OVEO and the cross-tolerance to NaCl, KCl and ROEO. In total, 300 DEGs after sublethal OVEO adaption were identified, including 145 upregulated and 155 downregulated. Firstly, OVEO stress could cause proton motive force (PMF) dissipation, Y. enterocolitica activated the phage shock protein response (3.3–3.7 log2(FC)) and reduced unnecessary energy consumption such as mobility, flagellum formation and quorum sensing to maintain the PMF balance and ensure the normal physiological function. Secondly, genes associated with synthesis and transport of glycerol-3-phosphate were upregulated 1.7–2.2 log2(FC) to repair the structure and function of cell membrane under OVEO stress. Besides, PstSCAB transporter of phosphotransferase system were activated to ensure the energy supply and cell constituents synthesis under OVEO stress. Finally, Y. enterocolitica prevented the cell from oxidization damage by increasing the expression of glutathione peroxidase and amino acid synthesis-associated genes (2.0–3.9 log2(FC)).