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ARS Home » Southeast Area » Auburn, Alabama » Aquatic Animal Health Research » Research » Publications at this Location » Publication #410057
Research Project: Integrated Research to Improve Aquatic Animal Health in Warmwater Aquaculture

Location: Aquatic Animal Health Research

Title: The role of quorum sensing response regulator luxr on Flavobacterium covae biofilm formation and virulence in channel catfish (Ictalurus punctatus)

Author
item WHITE, RACHEL - Auburn University
item CHURCHMAN, EMILY - Auburn University
item XU, TINGBI - Auburn University
item Lange, Miles
item LAFRENTZ, STACEY - Auburn University
item Lafrentz, Benjamin
item LILES, MARK - Auburn University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/30/2023
Publication Date: 11/3/2023
Citation: White, R.E., Churchman, E.M., Xu, T., Lange, M.D., Lafrentz, S., Lafrentz, B.R., Liles, M.R. 2023. The role of quorum sensing response regulator luxr on Flavobacterium covae biofilm formation and virulence in channel catfish (Ictalurus punctatus) [ABSTRACT]. Southeastern Branch of the American Society for Microbiology Annual Meeting, Auburn, AL, November 3-5, 2023.

Interpretive Summary:

Technical Abstract: Columnaris disease leads to massive losses in catfish aquaculture due to the bacterial pathogen Flavobacterium covae. It has been speculated that biofilm formation on skin and gill surfaces may contribute to pathogenicity. Previous research has shown that catfish mucus significantly upregulates the quorum sensing response regulator LuxR in F. covae biofilms. Since quorum sensing is known to regulate biofilm production and virulence in other aquatic pathogens, we hypothesized that LuxR has a similar role in F. covae. A luxR deletion mutant ('luxR) was constructed in F. covae C#2 using an allelic exchange method. Microtiter biofilm formation was quantified for the wild-type and 'luxR mutant. A significant increase of biofilm production was observed in the 'luxR mutant compared to the wild-type strain. Interestingly, when supplemented with 10 mM mannose, the wild-type strain exhibited an increase in biofilm formation while the 'luxR mutant remained unaffected. These results suggest a phenotypic difference in biofilm formation due to the luxR deletion. Recently, the 'luxR mutant has been complemented with a plasmid containing the luxR gene and the biofilm experiments will be repeated with the wild-type, 'luxR mutant and complemented 'luxR mutant. Future research includes evaluating the transcriptome of these strains to identify differentially expressed genes and determining the role of LuxR in virulence by in vivo infection of channel catfish. Collectively, these data will yield greater insights into the role of LuxR in F. covae biofilm formation and pathogenesis.