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Indole signalling and (micro)algal auxins decrease the virulence of Vibrio campbellii, a major pathogen of aquatic
Qian Yang1, Gde Sasmita Julyantoro Pande1, Zheng Wang2
1Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Gent, Belgium.
Environmental Microbiology
|March 3, 2017
Summary
Indole, a compound found in aquatic environments, acts as a starvation signal in Vibrio campbellii, reducing its virulence and impacting marine ecosystems. This discovery sheds light on pathogen-host interactions and microbial signaling in marine environments.
Area of Science:
- Marine microbiology
- Bacterial pathogenesis
- Chemical ecology
Background:
- Vibrios of the Harveyi clade are significant marine pathogens impacting both wild and cultured organisms.
- The precise pathogenicity mechanisms of these bacteria remain incompletely understood.
- Indole signaling's role in Vibrio virulence has not been fully elucidated.
Purpose of the Study:
- To investigate the impact of indole signaling on the virulence of Vibrio campbellii.
- To understand how indole affects bacterial processes like motility, biofilm formation, and quorum sensing.
- To explore the potential role of indole as a starvation signal and its interaction with other regulatory pathways.
Main Methods:
- Assessing the effects of elevated indole levels on V. campbellii virulence factors.
- Investigating indole's impact on the quorum sensing system and RpoS.
- Utilizing microarray-based transcriptomics to analyze gene expression changes.
- Examining the effects of algal-derived auxins on V. campbellii.
Main Results:
- Increased indole levels significantly reduced V. campbellii motility, biofilm formation, exopolysaccharide production, and crustacean host virulence.
- Indole inhibited the quorum sensing system and interacted with the stress sigma factor RpoS.
- Indole downregulated genes involved in energy and amino acid metabolism, suggesting it acts as a starvation signal.
- Algal-derived auxins (indole-3-acetic acid and indole-3-acetamide) mimicked indole's effects.
Conclusions:
- Indole acts as a starvation signal in V. campbellii, downregulating virulence and energy-consuming processes.
- Indole signaling influences quorum sensing and stress response pathways in V. campbellii.
- Auxins produced by microalgae can modulate Vibrio virulence, indicating complex ecological interactions with significant implications.
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