sRNAs Regulate Biofilm Formation via Quorum Sensing and Chemotaxis systems in <em>Listeria monocytogenes</em>

<em>Listeria monocytogenes </em>(<em>L. monocytogenes</em>) is a highly concerning food-borne pathogen, and its biofilm formation has a significant impact on food safety. Small RNAs (sRNAs) play a crucial role in the biofilm formation of <em>L. monocytogenes</em>. We identified three sRNAs potentially associated with biofilm formation: ssrS, sRNA003, and sRNA006. Notably, sRNA003 and sRNA006 were newly discovered. This study explored the effects of three sRNAs on biofilm formation in <em>L. monocytogenes</em> and their regulatory mechanisms. Deletion of these sRNAs resulted in a 40% reduction in biofilm formation, affecting all stages of the biofilm-forming process. Real-time quantitative PCR (RT-qPCR) results showed significant differences in the transcription levels of key genes in the quorum sensing and chemotaxis systems at various growth phases compared to the wild-type. These sRNAs alter gene expression by affecting promoter activity and bind to the 5' untranslated region (UTR) of key genes in quorum sensing and chemotaxis systems, thus influencing mRNA stability and regulating biofilm formation at the post-transcriptional level. Additionally, we predicted and validated the binding sites between these sRNAs and their target mRNAs. This study elucidated the pathways through which sRNAs regulate biofilm formation in <em>L. monocytogenes</em> at the post-transcriptional level. These findings highlight the potential of sRNAs as targets for novel antibacterial strategies, contributing to the control of <em>L. monocytogenes</em> and the reduction of biofilm-related issues in the food industry.