Use of Bacterial Quorum-Sensing Components to Regulate Gene Expression in Plants

Bacteria are able to synchronize the population behavior in order to regulate gene expression through a cell-to-cell communication mechanism called quorum sensing. This phenomenon involves the production, detection and the response to extracellular signaling molecules named autoinducers, which directly or indirectly regulate gene expression in a cell density-dependent manner. Quorum sensing may control a wide range of biological processes in bacteria, such as bioluminescence, virulence factor production, biofilm formation and antibiotic resistance. The autoinducers are recognized by specific receptors that can either be membrane-bound histidine kinase receptors, which work by activating cognate cytoplasmic response regulators, or cytoplasmic receptors acting as transcription factors. In this review, we focused on the cytosolic quorum sensing regulators whose three-dimensional structures helped elucidate their mechanisms of action. Structural studies of quorum sensing receptors may enable the rational design of inhibitor molecules. Ultimately, this approach may represent an effective alternative to treat infections where classical antimicrobial therapy fails to overcome the microorganism virulence.

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Implications of Rewiring Bacterial Quorum Sensing

Applied and Environmental Microbiology ◽

10.1128/aem.01688-07 ◽

2007 ◽

Vol 74 (2) ◽

pp. 437-445 ◽

Cited By ~ 50

Author(s):

Eric L. Haseltine ◽

Frances H. Arnold

Keyword(s):

Gene Expression ◽

Quorum Sensing ◽

Network Architecture ◽

Vibrio Fischeri ◽

Cell Communication ◽

Biologically Relevant ◽

Synthetic Gene Circuits ◽

Bacterial Quorum Sensing ◽

Forward Engineering ◽

Bacterial Quorum

ABSTRACT Bacteria employ quorum sensing, a form of cell-cell communication, to sense changes in population density and regulate gene expression accordingly. This work investigated the rewiring of one quorum-sensing module, the lux circuit from the marine bacterium Vibrio fischeri. Steady-state experiments demonstrate that rewiring the network architecture of this module can yield graded, threshold, and bistable gene expression as predicted by a mathematical model. The experiments also show that the native lux operon is most consistent with a threshold, as opposed to a bistable, response. Each of the rewired networks yielded functional population sensors at biologically relevant conditions, suggesting that this operon is particularly robust. These findings (i) permit prediction of the behaviors of quorum-sensing operons in bacterial pathogens and (ii) facilitate forward engineering of synthetic gene circuits.

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The Vitamin Riboflavin and Its Derivative Lumichrome Activate the LasR Bacterial Quorum-Sensing Receptor

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-21-9-1184 ◽

2008 ◽

Vol 21 (9) ◽

pp. 1184-1192 ◽

Cited By ~ 88

Author(s):

Sathish Rajamani ◽

Wolfgang D. Bauer ◽

Jayne B. Robinson ◽

John M. Farrow ◽

Everett C. Pesci ◽

...

Keyword(s):

Gene Expression ◽

Quorum Sensing ◽

Binding Pocket ◽

Homoserine Lactone ◽

Docking Studies ◽

Intercellular Signaling ◽

Signaling Mechanism ◽

Bacterial Quorum Sensing ◽

Bacterial Quorum ◽

Regulated Gene Expression

Many bacteria use quorum sensing (QS) as an intercellular signaling mechanism to regulate gene expression in local populations. Plant and algal hosts, in turn, secrete compounds that mimic bacterial QS signals, allowing these hosts to manipulate QS-regulated gene expression in bacteria. Lumichrome, a derivative of the vitamin riboflavin, was purified and chemically identified from culture filtrates of the alga Chlamydomonas as a QS signal-mimic compound capable of stimulating the Pseudomonas aeruginosa LasR QS receptor. LasR normally recognizes the N-acyl homoserine lactone (AHL) signal, N-3-oxo-dodecanoyl homoserine lactone. Authentic lumichrome and riboflavin stimulated the LasR receptor in bioassays and lumichrome activated LasR in gel shift experiments. Amino acid substitutions in LasR residues required for AHL binding altered responses to both AHLs and lumichrome or riboflavin. These results and docking studies indicate that the AHL binding pocket of LasR recognizes both AHLs and the structurally dissimilar lumichrome or riboflavin. Bacteria, plants, and algae commonly secrete riboflavin or lumichrome, raising the possibility that these compounds could serve as either QS signals or as interkingdom signal mimics capable of manipulating QS in bacteria with a LasR-like receptor.

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The abaI/abaR quorum sensing system effects pathogenicity in Acinetobacter baumannii

10.1101/2021.01.19.427366 ◽

2021 ◽

Author(s):

Xiaoyu Sun ◽

Zhaohui Ni ◽

Jie Tang ◽

Yue Ding ◽

Xinlei Wang ◽

...

Keyword(s):

Quorum Sensing ◽

Acinetobacter Baumannii ◽

Biofilm Formation ◽

Cell Communication ◽

Regulate Gene Expression ◽

Sensing System ◽

Quorum Sensing System ◽

Bacterial Quorum Sensing ◽

Bacterial Quorum

ABSTRACTAcinetobacter baumannii is a Gram-negative pathogen that has emerged as one of the most troublesome pathogens for health care institutions globally. Bacterial quorum sensing (QS) is a process of cell-to-cell communication that relies on the production, secretion and detection of autoinducer (AI) signals to share information about cell density and regulate gene expression accordingly. In this study, we performed a comprehensive set of experiments show that deletion of quorum sensing genes showed differences in growth characteristics, morphology, biofilm formation and virulence, and increased susceptibility to some antimicrobials and exhibited motility defects. RNA-seq analysis indicated that genes involved in various aspects of energy production and conversion, Valine, leucine and isoleucine degradation and lipid transport and metabolism showed different expression.IMPORTANCEPrevious studies on bacterial quorum sensing mainly focused on biofilm formation and motility and antibiotic resistance. In this study, we focused on detecting the role of the abaI/abaR QS system in the virulence of A. baumannii. Our work provides a new insight into abaI/abaR quorum sensing system effects pathogenicity in A. baumannii. We propose that targeting the AHL synthase enzyme abaI could provide an effective strategy for attenuating virulence. On the contrary, interdicting the autoinducer synthase–receptor abaR elicits unpredictable consequences, which may lead to enhanced bacterial virulence.

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The abaI/abaR Quorum Sensing System Effects on Pathogenicity in Acinetobacter baumannii

Frontiers in Microbiology ◽

10.3389/fmicb.2021.679241 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xiaoyu Sun ◽

Zhaohui Ni ◽

Jie Tang ◽

Yue Ding ◽

Xinlei Wang ◽

...

Keyword(s):

Quorum Sensing ◽

Acinetobacter Baumannii ◽

Cell Communication ◽

Homoserine Lactone ◽

Rna Seq ◽

Regulate Gene Expression ◽

Bacterial Pathogenicity ◽

Bacterial Quorum Sensing ◽

Bacterial Quorum ◽

Insight Into

Acinetobacter baumannii is a Gram-negative pathogen that has emerged as one of the most troublesome pathogens for healthcare institutions globally. Bacterial quorum sensing (QS) is a process of cell-to-cell communication that relies on the production, secretion, and detection of autoinducer (AI) signals to share information about cell density and regulate gene expression accordingly. The molecular and genetic bases of A. baumannii virulence remains poorly understood. Therefore, the contribution of the abaI/abaR QS system to growth characteristics, morphology, biofilm formation, resistance, motility, and virulence of A. baumannii was studied in detail. RNA sequencing (RNA-seq) analysis indicated that genes involved in various aspects of energy production and conversion; valine, leucine, and isoleucine degradation; and lipid transport and metabolism are associated with bacterial pathogenicity. Our work provides a new insight into the abaI/abaR QS system effects on pathogenicity in A. baumannii. We propose that targeting the acyl homoserine lactone (AHL) synthase enzyme abaI could provide an effective strategy for attenuating virulence. On the contrary, interdicting the AI synthase receptor abaR elicits unpredictable consequences, which may lead to enhanced bacterial virulence.

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