ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Antimicrobials, Resistance and Chemotherapy
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1606567
This article is part of the Research TopicBreaking the Biofilm Barrier: Analysis of Molecular Mechanisms Underlying Biofilm Formation and Identification of Novel Antimicrobial ApproachesView all 7 articles
FliA regulates the antibacterial activity of plantaricin BM-1 against Escherichia coli K-12 through the LuxS/AI-2 quorum-sensing-mediated biofilm formation
Provisionally accepted- 1Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, College of Food Science and Engineering, Beijing University of Agriculture, Beijing, China
- 2Key Laboratory of Dairy Quality Digital Intelligence Monitoring Technology, State Administration for Market Regulation,Inner Mongolia Mengniu Dairy (Group) Co., Ltd., Hohhot, Inner Mongolia Autonomous Region, China
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Plantaricin BM-1 is a class IIa bacteriocin active against Escherichia coli. However, the mode of action of class IIa bacteriocins against gram-negative bacteria remains unclear. In this study, the regulatory role of sigma factor FliA (σ28) in the antibacterial mechanism of plantaricin BM-1 against E. coli K-12 BW25113 is evaluated. The fliA-complemented strain of E. coli JW1907, namely E. coli ReJW1907, was constructed through λ-Red homologous recombination. The effects of plantaricin BM-1 on E. coli growth, cell morphology, and membrane integrity were investigated using growth curves, electron microscopy, and flow cytometry. The biofilm formation ability of E. coli was evaluated using crystal violet staining and confocal laser scanning microscopy. Transcriptomic analysis was performed to screen for differentially expressed genes (DEGs). The inhibition rate (I%) of plantaricin BM-1 (3.75 mg/mL) against E. coli JW1907 (89.22 ± 1.13%) at the 8th h of culture was significantly higher than that of E. coli BW25113 (70.36 ± 6.30%) and ReJW1907 (74.75 ± 4.99%). The biofilm biomass produced by E. coli BW25113 (OD595 nm = 0.343 ± 0.056) was significantly reduced to 0.227 ± 0.04 after fliA deletion, and was recovered to its original level (0.358 ± 0.027) after fliA complement. A total of 205 DEGs were identified between E. coli BW25113 and JW1907. Among these, four DEGs (fliZ, wza, lsrR, and pgaA) were enriched in the biofilm formation pathway. Further analysis revealed eight up-regulated DEGs (lsrKRBDCAFG), which were significantly enriched in the LuxS/AI-2 quorum sensing (QS) system. After the deletion of any gene from lsrKRBDCAFG, the I% of plantaricin BM-1 against E. coli BW25113 (70.77 ± 7.01%) was significantly increased to 80.68–90.06%, with its biofilm production (0.254 ± 0.014) reduced to 0.135–0.188. In conclusion, FliA modulates biofilm formation through the LuxS/AI-2 QS system, thereby regulating the antibacterial activity of plantaricin BM-1. Overall, these findings improve our understanding of the bacteriostatic mechanism of class IIa bacteriocins against gram-negative bacteria.
Keywords: Class IIa bacteriocins, Escherichia coli, FliA, Biofilm formation, Transcriptome
Received: 07 Apr 2025; Accepted: 30 May 2025.
Copyright: © 2025 Wang, Song, Zheng, Cheng, Jin, Xie and Zhang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Yuanhong Xie, Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, College of Food Science and Engineering, Beijing University of Agriculture, Beijing, China
Hongxing Zhang, Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, College of Food Science and Engineering, Beijing University of Agriculture, Beijing, China
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