Unraveling the degradation mechanism of multiple pyrethroid insecticides by Pseudomonas aeruginosa and its environmental bioremediation potential.

Extensive use of pyrethroid insecticides poses significant risks to both ecological ecosystems and human beings. Herein, Pseudomonas aeruginosa PAO1 exhibited exceptional degradation capabilities towards a range of pyrethroid family insecticides including etofenprox, bifenthrin, tetramethrin, D-cypermethrin, allethrin, and permethrin, with a degradation efficiency reaching over 84 % within 36 h (50 mg·L). Strain PAO1 demonstrated effective soil bioremediation by removing etofenprox across different concentrations (25-100 mg·kg), with a degradation efficiency over 77 % within 15 days.

Diversity and Pathogenic Mechanisms.

The genus comprises numerous pathogenic species that cause diseases in various crops, vegetables, and ornamental plants across the globe. The pathogens have become very widespread in recent years, and numerous newly identified -associated plant diseases have been reported, which poses an immense threat to agricultural production and is a serious concern internationally. Evidence is accumulating that a diversity of hosts, environmental habitats, and climates seems to shape the abundance of species in nature and the differentiation of pathogenic mechanisms.

Protocol for examining the T3SS-mediated cytotoxicity of Pseudomonas aeruginosa using the A549 cell line.

Pseudomonas aeruginosa utilizes a type III secretion system (T3SS) to directly inject effector proteins into host cells, leading to severe acute infections. Here, we present a protocol for detecting the T3SS-mediated cytotoxicity of P. aeruginosa using the A549 cell line.

Regulation of Burkholderia cenocepacia virulence by the fatty acyl-CoA ligase DsfR as a response regulator of quorum sensing signal.

Quorum sensing (QS) is a cell-to-cell communication mechanism mediated by small diffusible signaling molecules. Previous studies showed that RpfR controls Burkholderia cenocepacia virulence as a cis-2-dodecenoic acid (BDSF) QS signal receptor. Here, we report that the fatty acyl-CoA ligase DsfR (BCAM2136), which efficiently catalyzes in vitro synthesis of lauryl-CoA and oleoyl-CoA from lauric acid and oleic acid, respectively, acts as a global transcriptional regulator to control B.

Pathogenic and Comparative Genomic Analysis of Isolated from .

is crucial in protecting coastal regions of China against typhoon attacks but has faced a substantial challenge due to wilt disease caused by pathogens of the species complex (RSSC). Although the initial outbreak of wilt in the 1970s was effectively controlled by disease-resistant varieties, the disease has recently re-emerged in coastal regions of Guangdong. In this study, we report the isolation, characterization, and comparative genomic analysis of 11 RSSC strains from diseased at various locations along the coast of Guangdong.

Suppression of type III secretion system by a novel calcium-responsive signaling pathway.

Expression of the type III secretion system (T3SS) in is exquisitely controlled by diverse environmental or host-related signals such as calcium (Ca), however, the signal transduction pathways remain largely elusive. In this study, we reported that FleR, the response regulator of the two-component system FleS/FleR, inhibits T3SS gene expression and virulence of uncoupled from its cognate histidine kinase FleS. Interestingly, FleR was found to repress T3SS gene expression under Ca-rich conditions independently of its DNA-binding domain.

FlgI Is a Sec-Dependent Effector of Liberibacter asiaticus That Can Be Blocked by Small Molecules Identified Using a Yeast Screen.

Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide. The phloem-restricted bacterium Liberibacter asiaticus (CLas) is considered to be the main pathogen responsible for HLB. There is currently no effective practical strategy for the control of HLB.

Regulation of the physiology and virulence of Ralstonia solanacearum by the second messenger 2',3'-cyclic guanosine monophosphate.

Previous studies have demonstrated that bis-(3',5')-cyclic diguanosine monophosphate (bis-3',5'-c-di-GMP) is a ubiquitous second messenger employed by bacteria. Here, we report that 2',3'-cyclic guanosine monophosphate (2',3'-cGMP) controls the important biological functions, quorum sensing (QS) signaling systems and virulence in Ralstonia solanacearum through the transcriptional regulator RSp0980. This signal specifically binds to RSp0980 with high affinity and thus abolishes the interaction between RSp0980 and the promoters of target genes.

Polyamine signaling communications play a key role in regulating the pathogenicity of .

is a newly identified plant bacterial pathogen with a wide host range. A clear understanding of the cell-to-cell communication systems that modulate the bacterial virulence is of key importance for elucidating its pathogenic mechanisms and for disease control. In this study, we present evidence that putrescine molecules from the pathogen and host plants play an essential role in regulating the bacterial virulence.

Pseudomonas chlororaphis L5 and Enterobacter asburiae L95 biocontrol Dickeya soft rot diseases by quenching virulence factor modulating quorum sensing signal.

Virulence factor modulating (VFM) is a quorum sensing (QS) signal shared by and specific to Dickeya bacteria, regulating the production of plant cell wall degrading enzymes (PCWDEs) and virulence of Dickeya. High polarity and trace of VFM signal increase the difficulty of signal separation and structure identification, and thus limit the development of quorum quenching strategy to biocontrol bacterial soft rot diseases caused by Dickeya. In order to high-throughput screen VFM quenching bacteria, a vfmE-gfp biosensor VR2 (VFM Reporter) sensitive to VFM signal was first constructed.

Characterization of the Arn lipopolysaccharide modification system essential for zeamine resistance unveils its new roles in Dickeya oryzae physiology and virulence.

The zeamines produced by Dickeya oryzae are potent polyamine antibiotics and phytotoxins that are essential for bacterial virulence. We recently showed that the RND efflux pump DesABC in D. oryzae confers partial resistance to zeamines.

The Isolate QL-9a Quenches the Quorum Sensing Signal and Suppresses Plant Soft Rot Disease.

Quorum sensing (QS) is a communication mechanism used among microorganisms that regulate the population density and behavior by sensing the concentration of signaling molecules. Quorum quenching (QQ), a novel, eco-friendly, and efficient method for disease control, interferes with QS by disturbing the production and enzymatic degradation of signaling molecules, blocking communication among microorganisms, and thus has deep potential for use in plant disease control. can cause bacterial soft rot, resulting in yield reduction in a variety of crops worldwide, and can be mediated and regulated by the -acyl homoserine lactones (AHLs), which are typical signaling molecules.

A type I-F CRISPRi system unveils the novel role of CzcR in modulating multidrug resistance of .

has abundant signaling systems that exquisitely control its antibiotic resistance in response to different environmental cues. Understanding the regulation of antibiotic resistance will provide important implications for precise antimicrobial interventions. However, efficient genetic tools for functional gene characterizations are sometimes not available, particularly, in clinically isolated strains.

sp. nov. and biocontrol bacterial wilt by quenching 3-hydroxypalmitic acid methyl ester.

Bacterial wilt caused by ranks the second top important bacterial plant disease worldwide. It is also the most important bacterial disease threatening the healthy development of protection forest. 3-hydroxypalmitic acid methyl ester (3-OH PAME) functions as an important quorum sensing (QS) signal regulating the expression of virulence genes in , and has been regarded as an ideal target for disease prevention and control.

Mechanisms of Virulence Reprogramming in Bacterial Pathogens.

Bacteria are single-celled organisms that carry a comparatively small set of genetic information, typically consisting of a few thousand genes that can be selectively activated or repressed in an energy-efficient manner and transcribed to encode various biological functions in accordance with environmental changes. Research over the last few decades has uncovered various ingenious molecular mechanisms that allow bacterial pathogens to sense and respond to different environmental cues or signals to activate or suppress the expression of specific genes in order to suppress host defenses and establish infections. In the setting of infection, pathogenic bacteria have evolved various intelligent mechanisms to reprogram their virulence to adapt to environmental changes and maintain a dominant advantage over host and microbial competitors in new niches.

Gram-negative bacteria resist antimicrobial agents by a DzrR-mediated envelope stress response.

Background: Envelope stress responses (ESRs) are critical for adaptive resistance of Gram-negative bacteria to envelope-targeting antimicrobial agents. However, ESRs are poorly defined in a large number of well-known plant and human pathogens. Dickeya oryzae can withstand a high level of self-produced envelope-targeting antimicrobial agents zeamines through a zeamine-stimulated RND efflux pump DesABC.

Cell division factor ZapE regulates biofilm formation by impacting the quorum sensing system.

is one of the leading nosocomial pathogens that causes both severe acute and chronic infections. The strong capacity of to form biofilms can dramatically increase its antibiotic resistance and lead to treatment failure. The biofilm resident bacterial cells display distinct gene expression profiles and phenotypes compared to their free-living counterparts.

Innovative microbial disease biocontrol strategies mediated by quorum quenching and their multifaceted applications: A review.

With the increasing resistance exhibited by undesirable bacteria to traditional antibiotics, the need to discover alternative (or, at least, supplementary) treatments to combat chemically resistant bacteria is becoming urgent. Quorum sensing (QS) refers to a novel bacterial communication system for monitoring cell density and regulation of a network of gene expression that is mediated by a group of signaling molecules called autoinducers (AIs). QS-regulated multicellular behaviors include biofilm formation, horizontal gene transfer, and antibiotic synthesis, which are demonstrating increasing pathogenicity to plants and aquacultural animals as well as contamination of wastewater treatment devices.

Insights into the molecular basis of c-di-GMP signalling in .

The opportunistic human pathogen can cause severe infections in immunocompromized people or cystic fibrosis (CF) patients. Because of its remarkable ability to invade the host and withstand the bacteriocidal effect of most conventional antibiotics, the infection caused by has become a major concern for human health. The switch from acute to chronic infection is governed by the second messenger bis-(3'-5')-cyclic dimeric guanosine mono-phosphate (c-di-GMP) in , and c-di-GMP is now recognized to regulate many important biological processes in pathogenesis.

RdmA Is a Key Regulator in Autoinduction of DSF Quorum Quenching in Pseudomonas nitroreducens HS-18.

Diffusible signal factor (DSF) represents a family of widely conserved quorum-sensing (QS) signals which regulate virulence factor production and pathogenicity in numerous Gram-negative bacterial pathogens. We recently reported the identification of a highly potent DSF-quenching bacterial isolate, Pseudomonas nitroreducens HS-18, which contains an operon with four DSF-inducible genes, , or , that are responsible for degradation of DSF signals. However, the regulatory mechanisms that govern the response to DSF induction have not yet been characterized.

A novel bacterial strain sp. F25 capable of degrading diffusible signal factor signal shows strong biocontrol potential.

Vast quantities of synthetic pesticides have been widely applied in various fields to kill plant pathogens, resulting in increased pathogen resistance and decreased effectiveness of such chemicals. In addition, the increased presence of pesticide residues affects living organisms and the environment largely on a global scale. To mitigate the impact of crop diseases more sustainably on plant health and productivity, there is a need for more safe and more eco-friendly strategies as compared to chemical prevention.

tRNA modification enzyme MiaB connects environmental cues to activation of Pseudomonas aeruginosa type III secretion system.

Pseudomonas aeruginosa, a major inhabitant of numerous environmental reservoirs, is a momentous opportunistic human pathogen associated with severe infections even death in the patients suffering from immune deficiencies or metabolic diseases. Type III secretion system (T3SS) employed by P. aeruginosa to inject effector proteins into host cells is one of the pivotal virulence factors pertaining to acute infections caused by this pathogen.

CzcR Is Essential for Swimming Motility in Pseudomonas aeruginosa during Zinc Stress.

Two-component system (TCS) plays a vital role in modulating target gene expression in response to the changing environments. Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen that can survive under diverse stress conditions. The great adaptability of P.

Two-component system ArcBA modulates cell motility and biofilm formation in .

Phytopathogen is a causal agent of rice foot rot disease and the pathogen has an array of virulence factors, such as phytotoxin zeamines, plant cell wall degrading enzymes, cell motility, and biofilms, collectively contributing to the bacterial pathogenesis. In this study, through deletion analysis of predicted regulatory genes in EC1, we identified a two-component system associated with the regulation of bacterial virulence. The two-component system contains a histidine kinase ArcB and a response regulator ArcA, and deletion of their coding genes resulted in changed phenotypes in cell motility, biofilm formation, and bacterial virulence.

The virulence factor regulator and quorum sensing regulate the type I-F CRISPR-Cas mediated horizontal gene transfer in .

is capable of thriving in diverse environments due to its network of regulatory components for effective response to stress factors. The survival of the bacteria is also dependent on the ability to discriminate between the acquisition of beneficial and non-beneficial genetic materials horizontal gene transfer (HGT). Thus, bacteria have evolved the CRISPR-Cas adaptive immune system for defense against the deleterious effect of phage infection and HGT.