Transcriptome analysis of Micrococcus luteus in response to treatment with protocatechuic acid

Aim To reveal the antibacterial mechanism of protocatechuic acid (PCA) against Micrococcus luteus. Methods and Results M. luteus was exposed to PCA, and the antibacterial mechanism was revealed by measuring membrane potential, intracellular ATP and pH levels and transcriptome analysis. PCA induced the membrane potential depolarization of M. luteus, significantly decreased the intracellular ATP and pH levels of M. luteus and disrupted the integrity of the M. luteus cell membrane. Transcriptome analysis showed that PCA induced 782 differentially expressed genes (DEGs) of M. luteus. GO enrichment analysis revealed that the majority of DEGs are involved in pathways of metabolic process, cellular process, biological regulation and transport activity. In addition, PCA inhibited the growth of M. luteus in skimmed milk and extended the shelf life of skimmed milk. Conclusion PCA had good bactericidal activity against M. luteus through the mechanism of cell membrane disruption and metabolic process disorder. Significance and Impact of the Study PCA inhibits the growth of M. luteus in skimmed milk, suggesting that PCA is promising to be used as a novel preservative in food storage.