Transcriptomic Analysis of Staphylococcus aureus Under the Stress Condition Caused by Litsea cubeba L. Essential Oil via RNA Sequencing.

Litsea cubebaL. essential oil (LCEO) is a natural essential oil with considerable antimicrobial activity, and it can gradually replace some chemical additives in the food industry. However, the genetic evidences of stress response of bacteria under sub-lethal treatment with LCEO is limited. To this end, transcriptomic analysis ofStaphylococcus aureus29213 under a low concentration of LCEO was performed. Bacterial RNA samples were extracted from 1/4 MIC (0.07 mu L/mL) of LCEO-treated and non-treatedS. aureus29213. The transcriptional results were obtained by RNA sequencing (RNA-Seq). After treated with LCEO ofS. aureus29213, 300, and 242 genes were significantly up and down-regulated. Up-regulated genes were mainly related to cell membrane (wall) stress stimulon including genes related to two-component regulatory system (VraS), histidine metabolism (hisABCDetc.) and L-lysine biosynthesis (thrA, lysC, asdetc.). Significant differences were also founded between LCEO-treated and non-treated groups in peptidoglycan biosynthesis related pathways. Down-regulated genes were related to nitrogen metabolism (NarGHIJetc.), carotenoid biosynthesis (all) and pyruvate metabolism (phdA, pflB, pdhCetc.) ofS. aureus29213 in an LCEO-existing environment compared to the control. At the same time, we confirmed that LCEO can significantly affect the staphyloxanthin level ofS. aureus29213 for the first time, which is closely related to the redox state ofS. aureus29213. These evidences expanded the knowledge of stress response ofS. aureus29213 strain under sub-lethal concentration of LCEO.