Bacteriocin-induced mechanism of Wickerhamomyces anomalus Y-5 co-cultured with Lactiplantibacillus paraplantarum RX-8 by transcriptomic and proteomic analysis

Bacteriocin is a broad-spectrum antimicrobial active metabolite with a high potential for application in the food field. The previous studies found that co-culture of Wickerhamomyces anomalus Y-5 and Lactiplantibacillus paraplantarum RX-8 could increase the production of plantaricin RX-8. In order to investigate the induced mechanism of W. anomalus Y-5 in co-culture, this study explored the effects of induction components and contact mode on plantaricin RX-8; followed by transcriptomic and proteomic analyses of W. anomalus Y-5 in mono and co-culture systems, and screened differential metabolites by targeted metabolomic; finally, the potential inducing substances were subjected to validation experiments. The results indicated that the induced effect may not require direct cell contact, rather secretions constant stimulation. In co-culture system, W. anomalus Y-5 reduced nitrogen uptake, which allowed the release of the active Tap42 protein into the cytoplasm to stimulate the expression of retrograde genes, maintained biosynthesis of glutamic acid and glutamine. In addition, W. anomalus Y-5 was subjected to acid and osmotic stress, which resulted in activation of cAMP synthesis, inhibition of Ras protein activity, and up-regulation of Hxk2 expression. Further, we found that glutamine, inosine, guanosine, adenine, uracil, fumaric acid and pyruvic acid were the key substances that induced the production of plantaricin RX-8, and the optimal addition time was 8 h. In conclusion, these findings provided new perspectives on the identification of inducing substances and the analysis of production pathways in the efficient synthesis of bacteriocin induced by fungi, and lay the foundation for the industrial production of bacteriocin.