Abstract: In this study, changes in proteome and histone-like acetylation levels of Lactobacillus plantarum p-8 induced by linoleic acid (LA) were explored to investigate the mechanism of conjugated linoleic acid (CLA) production. The results showed that the optimal concentration of LA for inducing CLA production was 1 mg/mL. Proteomic analysis revealed that at this concentration, key protein factors for fatty acid synthesis such as enoyl acyl carrier protein (ACP) reductase and acyl carrier proteins were down-regulated, fatty acid synthesis was down-regulated, and acetyltransferase was up-regulated. Western blot showed that the increase in the content of acetyl-CoA upon NaAc addition resulted in elevated histone-like protein acetylation levels. The addition of LA and NaAc increased the mRNA expression of CLA-related enzymes, transcription factors (TF) and sigma factors, as determined by real-time polymerase chain reaction (real-time PCR), and increased the transformation rate of CLA. Correlation analysis yielded a significant positive correlation between the transcriptional levels of acetyl-CoA and linoleic acid hydratase (CLA-hy) and the transformation rate of CLA, revealing that the up-regulation of acetyl-CoA and acetyltransferase contents led to enhanced histone-like acetylation and consequent up-regulation of CLA synthesis. These results provide a basis for molecular modification and scientific regulation of lactic acid bacteria to improve CLA conversion.

Key words: linoleic acid; conjugated linoleic acid; Lactobacillus plantarum p-8; proteome; histone-like protein acetylation