Diversity of quorum sensing autoinducer synthases in the Global Ocean Sampling metagenomic database

Abstract

Quorum sensing (QS) is a cell-to-cell signalling pathway that allows bacteria to synchronize their genetic expression. It is mediated by autoinducers (AI), including (1) acyl-homoserine lactones (AHLs or AI-1), produced by Proteobacteria using AinS, LuxI and HdtS synthase families and (2) furanosyl-diester-borate (FDB or AI-2), produced by a large range of phylogenetically diverse bacteria and synthetized by the LuxS family. Few data have been collected about the presence and importance of QS in marine waters using culture independent methods. In this study, we examined the presence and the diversity of AI-1 and AI-2 synthases in the Global Ocean Sampling (GOS), a large metagenomic database, covering 68 stations across 3 oceans. We built 4 reference protein databases with maximal phylogenetic coverage containing all known AI synthase sequences to retrieve AI synthases sequences from the GOS metagenomes. We retrieved 29 environmental sequences affiliated to LuxI (synthesizing AI-1), 653 related to HdtS (AI-1), 31 related to LuxS (AI-2) and only one for AinS (AI-1). AI synthases sequences were found in the 3 oceans covered by the GOS cruise and spanned a large phylogenetic diversity. These data revealed a large number of new marine AI sequences, suggesting that QS based on AI-1 diffusion is a widespread mechanism in the marine environment.

Microbial Surface Colonization and Biofilm Development in Marine Environments

“…The liberation of dissolved nutrients and organic substrates may benefit surface-associated microorganisms, as well as Trichodesmium bacteria themselves for CO 2 and N 2 fixation, especially in oligotrophic environments. Diverse and novel autoinducer synthase genes have been identified in the Global Ocean Sampling metagenomic database, which covers 68 stations across three oceans (443). Many environmentally important microorganisms, including ammonia-oxidizing, nitrite-oxidizing, anammox, denitrifying, nitrogen-fixing, and sulfur-oxidizing bacteria as well as methanogenic Archaea, employ QS systems (416,435,(444)(445)(446)(447)(448).…”

Marine biofilms: diversity of communities and of chemical cues

“…For example, Cuadrado-Silva et al (2013) isolated several marine strains with QS systems mediated by different acyl homoserine lactones (AHLs, a class of common QS autoinducers): N-butanoyl homoserine lactone, Nhexanoyl homoserine lactone or both from fouled surfaces. Furthermore, a comprehensive study demonstrated the presence of several autoinducer synthases (responsible for the biosynthesis of different QS autoinducers) in three different oceans, encompassing a large phylogenetic diversity and underpinning its global prevalence (Doberva et al, 2015). The production of AHLs has been described in several marine Gram-negative bacteria (Parsek et al, 1999;Daniels et al, 2004), and the widespread occurrence of QS molecules in marine alphaproteobacteria has been shown for both free-living strains and those associated with eukaryotic algae (Wagner-Döbler et al, 2005).…”

“…Among marine bacteria, AI-2 is only known to function as a signal in Vibrio species (Milton, 2006) and AI-2 producing Vibrio species were found to be predominant and have an important role in microbial communities present in coral reefs or sponges (Tait et al, 2010;Zimmer et al, 2014). There are no much data regarding the presence of AI-2 signals in the ocean beyond coral communities, despite the fact that luxS gene sequences seem to be prevalent in the Global Ocean Sampling database (Doberva et al, 2015). Therefore, it is difficult so far to fully determine the importance of AI-2 in QS of marine bacteria and its role in marine biofilm formation.…”

Evaluation of two autoinducer-2 quantification methods for application in marine environments

“…; Doberva et al . ), implying that AI‐2 may be produced by marine micro‐organisms and can play a potential role in microbial‐associated problems (e.g. biofilm formation) prevalent in the seawater application systems.…”