Transcriptomic analysis of bacteriocin synthesis and stress response in Lactobacillus paracasei HD1.7 under acetic acid stress

Abstract

Bacteriocins from lactic acid bacteria are natural preservatives that inhibit foodborne pathogenic microorganisms and have recently attracted much attention. Acetic acid metabolism is part of the core of central metabolism. To elucidate the acetic acid stress response of L. paracasei HD1.7, we performed high-throughput RNA-seq to compare gene expression under different concentrations of acetic acid stress. The results showed that with increasing acetic acid stress, the concentration of bacteriocin was increased, its production rate was accelerated, and the number of differentially expressed genes also increased. The continuously upregulated and downregulated KEGG pathways adjusted to the increase in acetic acid stress. The late-stage regulatory system of bacteriocin synthesis was related to ABC transporters (OppABCDF system). Purine and pyrimidine metabolism may provide ATP for ABC transporters. Acetic acid stress reduced glutamate biosynthesis, but arginine biosynthesis increased to attenuate acid stress. In addition, the KEGG enrichment analysis results of different environmental stresses (acetic acid, HCl, citric acid and ethanol stress) indicated that ABC transporters and fatty acid metabolism were the keys to bacteria adapting to environmental stress. This experiment lays the foundation for further research on bacteriocins.