Quorum sensing signal production and inhibition by coral‐associated vibrios

Abstract

Corals are inhabited by complex communities of microbes that affect their growth and survival. Several studies suggest that coral disease may be attributed to the success of vibrios in out-competing other bacteria in the mucus and tissues of corals. Vibrios utilize a variety of quorum sensing (QS) signal molecules to regulate processes that could be used to colonize corals during adverse environmental conditions. We therefore screened a range of Vibrios isolated from a variety of healthy and diseased corals, for the production of the QS signal molecules, N-acylhomoserine lactones (AHLs) and the AI-2 (autoinducer-2) small furanone signal molecule. All 29 strains examined activated the AI-2 biosensor, but only 17 activated an AHL biosensor. Using reverse phase thin-layer chromatography, we showed that the effect of temperature on AHL production varied considerably among the isolates. For the first time, the QS inhibition by Vibrio harveyi is reported. This only occurred at higher temperatures and does not appear to be due to degradation of AHLs. The large diversity of vibrios and the different effects of temperature on signal production may partly explain the complexity of coral-associated community changes in response to environmental factors.

Microbiome shifts and the inhibition of quorum sensing by Black Band Disease cyanobacteria

“…Vibrios have previously been postulated to have a role in BBD (Barneah et al, 2007;Arotsker et al, 2009), although their contribution to the initiation and progression of the disease has yet to be characterized. Although vibrios were detected at moderately low levels in both healthy coral mucus and in the black band, vibrios are readily cultivable from both sample types and have QS activity through both the AHL-based autoinducer 1 system and the furanosyl borate diester-based autoinducer 2 system (Tait et al, 2010;Alagely et al, 2011a;Golberg et al, 2011Golberg et al, , 2013Zimmer et al, 2014). In addition to AHLs and AI-2, vibrios also produce hydroxyketone CAI-1 signals (Henke and Bassler, 2004;Ng et al, 2011;Wei et al, 2012), and with this study we demonstrate that coral vibrios also produce CAI-1-like activities.…”

Temperature regulation of virulence factors in the pathogen Vibrio coralliilyticus

“…Activation of these pathways result in the transcription of small RNAs, which subsequently degrade the messenger RNA of virulence factors (Ng and Bassler, 2009). Temperature has recently been shown to affect QS mechanisms (Tait et al, 2010). For example, V. mediterranei produces four N-Acyl homoserine lactone at 18 1C compared with only two at 25 1C and 30 1C (Tait et al, 2010), and there is evidence that temperature can affect the level of AHL production positively (Hasegawa et al, 2005;Latour et al, 2007) and negatively (Tait et al, 2010).…”

“…Temperature has recently been shown to affect QS mechanisms (Tait et al, 2010). For example, V. mediterranei produces four N-Acyl homoserine lactone at 18 1C compared with only two at 25 1C and 30 1C (Tait et al, 2010), and there is evidence that temperature can affect the level of AHL production positively (Hasegawa et al, 2005;Latour et al, 2007) and negatively (Tait et al, 2010). The Vc450 genome possesses three (AI-1/LuxMN, AI-2/LuxSPQ and CAI-1/CqsAS) two-component histidine kinase QS pathways ( Figure 5) and three small RNAs (Supplementary Figure 7), characteristic of those identified in the regulation of other Vibrio species QS (Lenz et al, 2004).…”

Exploiting Quorum Sensing To Confuse Bacterial Pathogens

“…Aquatic ecosystems continue to reveal diverse microorganism taxonomies and to yield enormous diversity in secondary metabolite products. Numerous reports are emerging that provide empirical data demonstrating QSI activity from various marine sources that include sponges (290), microalgae (291), bryozoa (292), and alga-and coral-associated bacteria (293,294). Low-micromolar concentrations of phenethylamide compounds from the marine bacterium Halobacillus salinus were found to inhibit V. harveyi luminescence and C. violaceum pigment production without inhibiting growth (295).…”