Profiling Signal Transduction in Global Marine Biofilms

Ruojun Wang,Wai Chuen Wong,Pei-Yuan Qian,Wei Ding,Weipeng Zhang,Lexin Long,Zhicong Liang

doi:10.3389/fmicb.2021.768926

Abstract

Microbes use signal transduction systems in the processes of swarming motility, antibiotic resistance, virulence, conjugal plasmid transfer, and biofilm formation. However, the signal transduction systems in natural marine biofilms have hardly been profiled. Here we analyzed signal transduction genes in 101 marine biofilm and 91 seawater microbial metagenomes. The abundance of almost all signal transduction-related genes in biofilm microbial communities was significantly higher than that in seawater microbial communities, regardless of substrate types, locations, and durations for biofilm development. In addition, the dominant source microbes of signal transduction genes in marine biofilms were different from those in seawater samples. Co-occurrence network analysis on signal communication between microbes in marine biofilms and seawater microbial communities revealed potential inter-phyla interactions between microorganisms from marine biofilms and seawater. Moreover, phylogenetic tree construction and protein identity comparison displayed that proteins related to signal transductions from Red Sea biofilms were highly similar to those from Red Sea seawater microbial communities, revealing a possible biological basis of interspecies interactions between surface-associated and free-living microbial communities in a local marine environment. Our study revealed the special profile and enrichment of signal transduction systems in marine biofilms and suggested that marine biofilms participate in intercellular interactions of the local ecosystem where they were seeded.

Highlights

Signal transduction is a stimulus-response process wherein signals are identified and converted into gene activation, which typically results in cellular responses (Bourret and Silversmith, 2010; Gotoh et al, 2010)
We investigated the features of signal transduction in marine environment and found substantial differences in both the composition and abundance of signal transduction systems between the marine biofilm and seawater microbial communities
Marine environment is an ideal natural ecosystem to explore the collective features of signal transduction systems in biofilmassociated microbial communities compared with free-living microbes

Summary

Introduction

Signal transduction is a stimulus-response process wherein signals are identified and converted into gene activation, which typically results in cellular responses (Bourret and Silversmith, 2010; Gotoh et al, 2010). Microbes use multiple signal transduction systems to respond to environmental changes and mediate diverse physiological processes and intercellular communication, including antibiotic resistance, virulence, symbiotic bacteria-host interactions, and biofilm assemblage (Bassler and Losick, 2006; Boyer and Wisniewski-Dyé, 2009; Gotoh et al, 2010). A two-component system enhances bacitracin resistance in several Gram-positive bacteria, such as Bacillus subtilis, Staphylococcus aureus, and Enterococcus faecalis (Hiron et al, 2011; Dintner et al, 2014; Gebhard et al, 2014), and N-acyl homoserine lactone (AHLs) transduction systems are first discovered from marine Vibrio fischeri (Milton, 2006) and used as a weapon to Signal Transduction in Marine Biofilms compete for survival or to dominate in a natural niche (Defoirdt et al, 2008). Cyclic di-GMP (c-diGMP) decreases flagella-mediated motility, increases bacteria adherence, and enhances biofilm formation (Jenal and Malone, 2006; Wilksch et al, 2011)

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Results

Conclusion