Diversity of Bacteria with Quorum Sensing and Quenching Activities from Hydrothermal Vents in the Okinawa Trough

Abstract

Quorum sensing (QS) is a chemical communication system by which bacteria coordinate gene expression and social behaviors. Quorum quenching (QQ) refers to processes of inhibiting the QS pathway. Deep-sea hydrothermal vents are extreme marine environments, where abundant and diverse microbial communities live. However, the nature of chemical communication in bacteria inhabiting the hydrothermal vent is poorly understood. In this study, the QS and QQ activities with N-acyl homoserine lactones (AHLs) as the autoinducer were detected in bacteria isolated from hydrothermal vents in the Okinawa Trough. A total of 18 and 108 isolates possessed AHL-producing and AHL-degrading abilities, respectively. Bacteria mainly affiliated with Rhodobacterales, Hyphomicrobiales, Enterobacterales and Sphingomonadales showed QS activities; QQ was mainly associated with Bacillales, Rhodospirillales and Sphingomonadales. The results showed that the bacterial QS and QQ processes are prevalent in hydrothermal environments in the Okinawa Trough. Furthermore, QS significantly affected the activities of extracellular enzymes represented by β-glucosidase, aminopeptidase and phosphatase in the four isolates with higher QS activities. Our results increase the current knowledge of the diversity of QS and QQ bacteria in extreme marine environments and shed light on the interspecific relationships to better investigate their dynamics and ecological roles in biogeochemical cycling.

Unraveling the Diverse Profile of N-Acyl Homoserine Lactone Signals and Their Role in the Regulation of Biofilm Formation in Porphyra haitanensis-Associated Pseudoalteromonas galatheae

“…Additionally, metagenomics studies reported that Vibrionales, Pseudomonadales, or Alteromonadales are the main contributors to AHL production [ 32 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 ]. Furthermore, it has been demonstrated that Gammaproteobacteria AHL pathways regulate various traits that may have significance in biogeochemical processes, including biofilm regulation, production of hydrolytic enzymes, siderophores, and motility [ 48 , 49 ].…”

“…All the isolated bacteria were screened for AHL production using a 96-well microtiter plate assay [ 49 , 50 ] with slight modifications. In brief, the reporter strain A136 was grown overnight at 28 °C at 150 rpm in 5 mL LB broth supplemented with 50 μg/mL spectinomycin and 4.5 μg/mL tetracycline, while the test bacteria were grown in 75 μL LB broth in a 96-well microtiter plate.…”

Eddy-driven diazotroph distribution: horizontal variability prevails over particle sinking speed

“…Although not typically considered a major player in marine ecosystems, Hyphomicrobiales is a metabolically and morphologically heterogeneous group [51]. This group has been documented in studies focused on deep environments, such as hydrothermal vents displaying quorum sensing activities [52], or marine sediments, where it may be involved in organic matter degradation. Genera within Hyphomicrobiales include aerobic chemoheterotrophs and facultatively methylotrophs, whereas some can grow anaerobically by denitri cation or fermentation [53].…”