Identification of LuxR Family Regulators That Integrate Into Quorum Sensing Circuit in Vibrio parahaemolyticus

Abstract

Vibrio parahaemolyticus is one of the most important food-borne pathogens that cause economic and public health problems worldwide. Quorum sensing (QS) is a way for the cell-cell communication between bacteria that controls a wide spectrum of processes and phenotypic behaviors. In this study, we performed a systematic research of LuxR family regulators in V. parahaemolyticus and found that they influence the bacterial growth and biofilm formation. We then established a QS reporter plasmid based on bioluminescence luxCDABE operon of Vibrio harveyi and demonstrated that several LuxR family regulators integrated into QS circuit in V. parahaemolyticus. Thereinto, a novel LuxR family regulator, named RobA, was identified as a global regulator by RNA-sequencing analyses, which affected the transcription of 515 genes in V. parahaemolyticus. Subsequent studies confirmed that RobA regulated the expression of the exopolysaccharides (EPS) synthesis cluster and thus controlled the biofilm formation. In addition, bioluminescence reporter assays showed that RobA plays a key role in the QS circuit by regulating the expression of opaR, aphA, cpsQ-mfpABC, cpsS, and scrO. We further demonstrated that the regulation of RobA to EPS and MfpABC depended on OpaR and CpsQ, which combined the QS signal with bis-(3′-5′)-cyclic dimeric GMP to construct a complex regulatory network of biofilm formation. Our data provided new insights into the bacterial QS mechanisms and biofilm formation in V. parahaemolyticus.

Molecular Mechanisms and Applications of N-Acyl Homoserine Lactone-Mediated Quorum Sensing in Bacteria

“…In the V. fisheri QS system, autoinducers (AIs) and two essential proteins (LuxR and LuxI) regulate bioluminescence signal production. The LuxI enzyme produces the QS signal molecule (the N-3-oxo-hexanoyl-homoserine lactone), and LuxR is a transcription regulator that binds to the AHL signal and regulates bioluminescence via the luxCDABEG operon [ 9 ]. Following the discovery of the AHL-QS system, researchers discovered that AHL-QS is prevalent in a wide range of Proteobacteria and influences vital characteristics such as motility [ 10 ], pigment production [ 11 ], and biofilm formation [ 12 ].…”

The Antimicrobial Effect of Melissa officinalis L. Essential Oil on Vibrio parahaemolyticus: Insights Based on the Cell Membrane and External Structure

“…V. parahaemolyticus is recognized as a new species because of vibriosis related to the consumption of contaminated raw or undercooked seafood ( Ashrafudoulla et al, 2021 ). Sepsis has also been reported when wounds were exposed to the pathogen ( Zhong et al, 2021 ).…”

Quorum sensing signal synthases enhance Vibrio parahaemolyticus swarming motility

“…To determine the functions of these three QS sensor‐autoinducer pairs of V. parahaemolyticus , we first constructed deletion mutants in each of the genes and transformed a reporter plasmid containing the bioluminescence luxCDABE operon cloned from V. harveyi (Zhong et al, 2021) into all these mutants. By testing light production of the bioluminescence reporter in these mutants, we found that the mutants of Δ opaR and Δ cqsA vp /Δ luxM vp /Δ luxS vp (hereafter referred to as Δ3AI) could not produce light (Figure 2b), which indicated that the luxCDABE operon from the reporter plasmid could only be activated by OpaR in the presence of the signals synthesized by CqsA vp , LuxM vp , and LuxS vp .…”