The RNA Chaperone Hfq and Small Non-Coding RNAs Modulate the Biofilm Formation of the Fish Pathogen Yersinia ruckeri .

International journal of molecular sciences [Int J Mol Sci] 2025 May 15; Vol. 26 (10). Date of Electronic Publication: 2025 May 15.

The fish pathogen Yersinia ruckeri forms biofilms on abiotic surfaces, contributing to recurrent infections in aquaculture. Increasing evidence suggests that the RNA chaperone Hfq and small non-coding RNAs (sRNAs) are key regulators of bacterial biofilm formation. However, the regulatory mechanisms mediated by these factors remain largely unexplored in Y. ruckeri . In this study, we investigated the roles of Hfq and the Hfq-dependent sRNAs RprA, ArcZ, and RybB in the biofilm formation of Y. ruckeri . We first characterized the sRNAome of biofilm-forming cells, identifying the conserved RprA, ArcZ, and RybB, among the upregulated sRNAs. We then evaluated motility, biofilm formation, and architecture in strains lacking either hfq (Δ hfq ) or these sRNAs (ΔsRNA). Our results reveal that both Δ hfq and ΔsRNA strains exhibit significant alterations in biofilm and motility phenotypes, including changes in bacterial morphology and extracellular matrix. Furthermore, expression analyses indicate that these sRNAs modulate the transcription of key regulatory factors, flagellar and phosphodiesterase genes, ultimately influencing intracellular cyclic di-GMP levels, a key second messenger in biofilm formation. Together, our findings demonstrate that Hfq and its associated sRNAs play critical regulatory roles in Y. ruckeri biofilm formation by controlling the expression of genes involved in motility, bacterial envelope proteins, and c-di-GMP metabolism.

English

Publisher: MDPI Country of Publication: Switzerland NLM ID: 101092791 Publication Model: Electronic Cited Medium: Internet ISSN: 1422-0067 (Electronic) Linking ISSN: 14220067 NLM ISO Abbreviation: Int J Mol Sci Subsets: MEDLINE

Biofilms*/growth & development , Host Factor 1 Protein*/genetics , Host Factor 1 Protein*/metabolism , Yersinia ruckeri*/genetics , Yersinia ruckeri*/physiology , RNA, Small Untranslated*/genetics , RNA, Small Untranslated*/metabolism, Gene Expression Regulation, Bacterial ; Animals ; Bacterial Proteins/genetics ; Bacterial Proteins/metabolism ; RNA, Bacterial/genetics ; RNA, Bacterial/metabolism ; Molecular Chaperones/genetics ; Molecular Chaperones/metabolism ; Yersinia Infections/microbiology ; Yersinia Infections/veterinary ; Cyclic GMP/analogs & derivatives ; Cyclic GMP/metabolism ; Fishes/microbiology

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