Proteome analysis of virulent Aeromonas hydrophila reveals the upregulation of iron acquisition systems in the presence of a xenosiderophore

Authors: Lange, Miles; Abernathy, Jason; Shoemaker, Craig; Zhang, Dunhua; KIRBY, AUGUSTUS - Auburn University; PEATMAN, ERIC - Auburn University; Beck, Benjamin

Submitted to: FEMS Microbiology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2020
Publication Date: 10/12/2020
Citation: Lange, M.D., Abernathy, J.W., Shoemaker, C.A., Zhang, D., Kirby, A., Peatman, E., Beck, B.H. 2020. Proteome analysis of virulent Aeromonas hydrophila reveals the upregulation of iron acquisition systems in the presence of a xenosiderophore. FEMS Microbiology Letters. 367(20):1-8. https://doi.org/10.1093/femsle/fnaa169.
DOI: https://doi.org/10.1093/femsle/fnaa169

Interpretive Summary: The Gram-negative bacterium, Aeromonas hydrophila, has been responsible for extensive losses in the catfish industry for over a decade. Due to its significance and impact on the aquaculture industry continuing efforts to better understand the basic mechanisms that contribute to virulent A. hydrophila (vAh) outbreaks are urgently needed. Recent challenge models demonstrated that vAh cultured in the presence of the iron chelating agent deferoxamine mesylate (DFO), were more virulent to channel catfish (Ictalurus punctatus). Upregulated proteins identified among the TSB+DFO treatment were enriched for gene ontology groups including iron ion transport, siderophore transport and siderophore uptake transport, all iron acquisition pathways. Protein-protein interactions were also evaluated among the differentially expressed proteins and predicted that many of the upregulated iron acquisition proteins likely form functional physiological networks. The current study reveals potential mechanisms which could potentially be used to design new therapies including vaccines.

Technical Abstract: The Gram-negative bacterium, Aeromonas hydrophila, has been responsible for extensive losses in the catfish industry for over a decade. Due to this impact, there are ongoing efforts to understand the basic mechanisms that contribute to virulent A. hydrophila (vAh) outbreaks. Recent challenge models demonstrated that vAh cultured in the presence of the iron chelating agent deferoxamine mesylate (DFO) were more virulent to channel catfish (Ictalurus punctatus). Interestingly, differential gene expression of select iron acquisition genes was unremarkable between DFO and non-DFO cultures, posing the question: why the increased virulence? The current work sought to evaluate growth characteristics and protein expression of vAh after the addition of DFO. A comparative proteome analysis revealed differentially expressed proteins among tryptic soy broth (TSB) and TSB+DFO treatments. Upregulated proteins identified among the TSB+DFO treatment were enriched for gene ontology groups including iron ion transport, siderophore transport and siderophore uptake transport, all iron acquisition pathways. Protein-protein interactions were also evaluated among the differentially expressed proteins and predicted that many of the upregulated iron acquisition proteins likely form functional physiological networks. The proteome analysis of the vAh reveals valuable information about the basic biological processes likely leading to increased virulence during iron restriction in this organism.