scholarly journals The roles of histidine kinases in sensing host plant and cell–cell communication signal in a phytopathogenic bacterium

2019 ◽  
Vol 374 (1767) ◽  
pp. 20180311 ◽  
Author(s):  
Fang-Fang Wang ◽  
Wei Qian
Keyword(s):  
Xanthomonas Campestris ◽  
Cell Communication ◽  
Research Progress ◽  
Bacterial Cells ◽  
Histidine Kinases ◽  
Phytopathogenic Bacterium ◽  
Bacterial Diseases ◽  
Signal Perception ◽  
Communication Signal ◽  
Diffusible Signal Factor

It has long been known that phytopathogenic bacteria react to plant-specific stimuli or environmental factors. However, how bacterial cells sense these environmental cues remains incompletely studied. Recently, three kinds of histidine kinases (HKs) were identified as receptors to perceive plant-associated or quorum-sensing signals. Among these kinases, HK VgrS detects iron depletion by binding to ferric iron via an ExxE motif, RpfC binds diffusible signal factor (DSF) by its N-terminal peptide and activates its autokinase activity through relaxation of autoinhibition, and PcrK specifically senses plant hormone–cytokinin and elicits bacterial responses to oxidative stress. These HKs are critical sensors that regulate the virulence of a Gram-negative bacterium, Xanthomonas campestris pv. campestris . Research progress on the signal perception of phytopathogenic bacterial HKs suggests that inter-kingdom signalling between host plants and pathogens controls pathogenesis and can be used as a potential molecular target to protect plants from bacterial diseases. This article is part of the theme issue ‘Biotic signalling sheds light on smart pest management’.

The cis -2-dodecenoic acid (BDSF) quorum sensing system in Burkholderia cenocepacia

2022 ◽  
Author(s):  
Mingfang Wang ◽  
Xia Li ◽  
Shihao Song ◽  
Chaoyu Cui ◽  
Lian-Hui Zhang ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Bacterial Infections ◽  
Xanthomonas Campestris ◽  
Cell Communication ◽  
Burkholderia Cenocepacia ◽  
Bacterial Cells ◽  
Communication Signals ◽  
Signal Perception ◽  
Sensing System ◽  
Diffusible Signal Factor

It has been demonstrated that quorum sensing (QS) is widely employed by bacterial cells to coordinately regulate various group behaviors. Diffusible signal factor (DSF)-type signals have emerged as a growing family of conserved cell-cell communication signals. In addition to the DSF signal initially identified in Xanthomonas campestris pv. campestris, B urkholderia d iffusible s ignal f actor (BDSF, cis -2-dodecenoic acid) has been recognized as a conserved DSF-type signal with specific characteristics in both signal perception and transduction from DSF signals. Here, we review the history and current progress of the research of this type of signal, especially focusing on its biosynthesis, signaling pathways, and biological functions. We also discuss and explore the huge potential of targeting this kind of QS system as a new therapeutic strategy to control bacterial infections and diseases.

scholarly journals Identification of FadT as a Novel Quorum Quenching Enzyme for the Degradation of Diffusible Signal Factor in Cupriavidus pinatubonensis Strain HN-2

2021 ◽  
Vol 22 (18) ◽  
pp. 9862
Author(s):  
Xudan Xu ◽  
Tian Ye ◽  
Wenping Zhang ◽  
Tian Zhou ◽  
Xiaofan Zhou ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Xanthomonas Campestris ◽  
Cell Communication ◽  
Maximal Activity ◽  
Quorum Quenching ◽  
Site Directed Mutagenesis ◽  
Diffusible Signal Factor ◽  
High Enzymatic Activity ◽  
Xanthomonas Campestris Pv Campestris ◽  
Potential Use

Quorum sensing (QS) is a microbial cell–cell communication mechanism and plays an important role in bacterial infections. QS-mediated bacterial infections can be blocked through quorum quenching (QQ), which hampers signal accumulation, recognition, and communication. The pathogenicity of numerous bacteria, including Xanthomonas campestris pv. campestris (Xcc), is regulated by diffusible signal factor (DSF), a well-known fatty acid signaling molecule of QS. Cupriavidus pinatubonensis HN-2 could substantially attenuate the infection of XCC through QQ by degrading DSF. The QQ mechanism in strain HN-2, on the other hand, is yet to be known. To understand the molecular mechanism of QQ in strain HN-2, we used whole-genome sequencing and comparative genomics studies. We discovered that the fadT gene encodes acyl-CoA dehydrogenase as a novel QQ enzyme. The results of site-directed mutagenesis demonstrated the requirement of fadT gene for DSF degradation in strain HN-2. Purified FadT exhibited high enzymatic activity and outstanding stability over a broad pH and temperature range with maximal activity at pH 7.0 and 35 °C. No cofactors were required for FadT enzyme activity. The enzyme showed a strong ability to degrade DSF. Furthermore, the expression of fadT in Xcc results in a significant reduction in the pathogenicity in host plants, such as Chinese cabbage, radish, and pakchoi. Taken together, our results identified a novel DSF-degrading enzyme, FadT, in C. pinatubonensis HN-2, which suggests its potential use in the biological control of DSF-mediated pathogens.

scholarly journals Structural and Functional Characterization of Diffusible Signal Factor Family Quorum-Sensing Signals Produced by Members of the Burkholderia cepacia Complex

2010 ◽  
Vol 76 (14) ◽  
pp. 4675-4683 ◽  
Author(s):  
Yinyue Deng ◽  
Ji'en Wu ◽  
Leo Eberl ◽  
Lian-Hui Zhang
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Cepacia ◽  
High Performance ◽  
Xanthomonas Campestris ◽  
Functional Characterization ◽  
Cell Communication ◽  
Burkholderia Cenocepacia ◽  
Burkholderia Cepacia Complex ◽  
Communication Signals ◽  
Diffusible Signal Factor

ABSTRACT Previous work has shown that Burkholderia cenocepacia produces the diffusible signal factor (DSF) family signal cis-2-dodecenoic acid (C12:Δ2, also known as BDSF), which is involved in the regulation of virulence. In this study, we determined whether C12:Δ2 production is conserved in other members of the Burkholderia cepacia complex (Bcc) by using a combination of high-performance liquid chromatography, mass spectrometry, and bioassays. Our results show that five Bcc species are capable of producing C12:Δ2 as a sole DSF family signal, while four species produce not only C12:Δ2 but also a new DSF family signal, which was identified as cis,cis-11-methyldodeca-2,5-dienoic acid (11-Me-C12:Δ2,5). In addition, we demonstrate that the quorum-sensing signal cis-11-methyl-2-dodecenoic acid (11-Me-C12:Δ2), which was originally identified in Xanthomonas campestris supernatants, is produced by Burkholderia multivorans. It is shown that, similar to 11-Me-C12:Δ2 and C12:Δ2, the newly identified molecule 11-Me-C12:Δ2,5 is a potent signal in the regulation of biofilm formation, the production of virulence factors, and the morphological transition of Candida albicans. These data provide evidence that DSF family molecules are highly conserved bacterial cell-cell communication signals that play key roles in the ecology of the organisms that produce them.

scholarly journals The Host Plant Metabolite Glucose Is the Precursor of Diffusible Signal Factor (DSF) Family Signals in Xanthomonas campestris

2015 ◽  
Vol 81 (8) ◽  
pp. 2861-2868 ◽  
Author(s):  
Yinyue Deng ◽  
Xiaoling Liu ◽  
Ji'en Wu ◽  
Jasmine Lee ◽  
Shaohua Chen ◽  
...  
Keyword(s):  
Host Plant ◽  
Virulence Factor ◽  
Xanthomonas Campestris ◽  
Ethanol Extract ◽  
Burkholderia Cenocepacia ◽  
Content Type ◽  
Communication Signal ◽  
Factor Production ◽  
Diffusible Signal Factor ◽  
Virulence Factor Production

ABSTRACTPlant pathogenXanthomonas campestrispv. campestris producescis-11-methyl-2-dodecenoic acid (diffusible signal factor [DSF]) as a cell-cell communication signal to regulate biofilm dispersal and virulence factor production. Previous studies have demonstrated that DSF biosynthesis is dependent on the presence of RpfF, an enoyl-coenzyme A (CoA) hydratase, but the DSF synthetic mechanism and the influence of the host plant on DSF biosynthesis are still not clear. We show here that exogenous addition of host plant juice or ethanol extract to the growth medium ofX. campestrispv. campestris could significantly boost DSF family signal production. It was subsequently revealed thatX. campestrispv. campestris produces not only DSF but also BDSF (cis-2-dodecenoic acid) and another novel DSF family signal, which was designated DSF-II. BDSF was originally identified inBurkholderia cenocepaciato be involved in regulation of motility, biofilm formation, and virulence inB. cenocepacia. Functional analysis suggested that DSF-II plays a role equal to that of DSF in regulation of biofilm dispersion and virulence factor production inX. campestrispv. campestris. Furthermore, chromatographic separation led to identification of glucose as a specific molecule stimulating DSF family signal biosynthesis inX. campestrispv. campestris.13C-labeling experiments demonstrated that glucose acts as a substrate to provide a carbon element for DSF biosynthesis. The results of this study indicate thatX. campestrispv. campestris could utilize a common metabolite of the host plant to enhance DSF family signal synthesis and therefore promote virulence.

scholarly journals Xanthomonas campestris Promotes Diffusible Signal Factor Biosynthesis and Pathogenicity by Utilizing Glucose and Sucrose from Host Plants

2019 ◽  
Vol 32 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Chunyan Zhang ◽  
Mingfa Lv ◽  
Wenfang Yin ◽  
Tingyan Dong ◽  
Changqing Chang ◽  
...  
Keyword(s):  
Host Plant ◽  
Xanthomonas Campestris ◽  
Infection Process ◽  
Plant Metabolites ◽  
Multiple Strategies ◽  
Exogenous Addition ◽  
Diffusible Signal Factor ◽  
Signal Production ◽  
Induced Changes ◽  
Encoding Genes

The plant pathogen Xanthomonas campestris pv. campestris produces diffusible signal factor (DSF) quorum sensing (QS) signals to regulate its biological functions and virulence. Our previous study showed that X. campestris pv. campestris utilizes host plant metabolites to enhance the biosynthesis of DSF family signals. However, it is unclear how X. campestris pv. campestris benefits from the metabolic products of the host plant. In this study, we observed that the host plant metabolites not only boosted the production of the DSF family signals but also modulated the expression levels of DSF-regulated genes in X. campestris pv. campestris. Infection with X. campestris pv. campestris induced changes in the expression of many sugar transporter genes in Arabidopsis thaliana. Exogenous addition of sucrose or glucose, which are the major products of photosynthesis in plants, enhanced DSF signal production and X. campestris pv. campestris pathogenicity in the Arabidopsis model. In addition, several sucrose hydrolase–encoding genes in X. campestris pv. campestris and sucrose invertase–encoding genes in the host plant were notably upregulated during the infection process. These enzymes hydrolyzed sucrose to glucose and fructose, and in trans expression of one of these enzymes, CINV1 of A. thaliana or XC_0805 of X. campestris pv. campestris, enhanced DSF signal biosynthesis in X. campestris pv. campestris in the presence of sucrose. Taken together, our findings demonstrate that X. campestris pv. campestris applies multiple strategies to utilize host plant sugars to enhance QS and pathogenicity.

scholarly journals The Phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) Is a Pathogen of the Pea Aphid

2006 ◽  
Vol 72 (3) ◽  
pp. 1956-1965 ◽  
Author(s):  
Anne-Marie Grenier ◽  
Gabrielle Duport ◽  
Sylvie Pagès ◽  
Guy Condemine ◽  
Yvan Rahbé
Keyword(s):  
Acyrthosiphon Pisum ◽  
Ecological Impact ◽  
Sitophilus Oryzae ◽  
Pea Aphid ◽  
Erwinia Chrysanthemi ◽  
Future Research ◽  
Close Relative ◽  
Bacterial Cells ◽  
Dickeya Dadantii ◽  
Phytopathogenic Bacterium

ABSTRACT Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research.

scholarly journals Emerging Role of Exosomes in Tuberculosis: From Immunity Regulations to Vaccine and Immunotherapy

2021 ◽  
Vol 12 ◽  
Author(s):  
Yin-Fu Sun ◽  
Jiang Pi ◽  
Jun-Fa Xu
Keyword(s):  
Immune Responses ◽  
Delivery System ◽  
Immune Modulation ◽  
Immune Cell ◽  
Critical Role ◽  
Cell Communication ◽  
Immune Defense ◽  
Research Progress ◽  
Recent Research Progress

Exosomes are cell-derived nanovesicles carrying protein, lipid, and nucleic acid for secreting cells, and act as significant signal transport vectors for cell-cell communication and immune modulation. Immune-cell-derived exosomes have been found to contain molecules involved in immunological pathways, such as MHCII, cytokines, and pathogenic antigens. Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), remains one of the most fatal infectious diseases. The pathogen for tuberculosis escapes the immune defense and continues to replicate despite rigorous and complicate host cell mechanisms. The infected-cell-derived exosomes under this circumstance are found to trigger different immune responses, such as inflammation, antigen presentation, and activate subsequent pathways, highlighting the critical role of exosomes in anti-MTB immune response. Additionally, as a novel kind of delivery system, exosomes show potential in developing new vaccination and treatment of tuberculosis. We here summarize recent research progress regarding exosomes in the immune environment during MTB infection, and further discuss the potential of exosomes as delivery system for novel anti-MTB vaccines and therapies.

scholarly journals A Technique for Precise Inoculation of the Internal Phyllosphere of Cotton with Xanthomonas campestris pv. malvacearum

2003 ◽  
Vol 93 (10) ◽  
pp. 1204-1208 ◽  
Author(s):  
N. Kangatharalingam ◽  
Margaret L. Pierce ◽  
Margaret Essenberg
Keyword(s):  
Xanthomonas Campestris ◽  
Bacterial Population ◽  
Guard Cells ◽  
Distilled Water ◽  
Circular Area ◽  
Phytopathogenic Bacterium ◽  
Spongy Mesophyll ◽  
Adaxial Surface ◽  
Custom Made ◽  
Palisade Cells

A technique was developed to inoculate uniformly and gently the internal phyllosphere from the upper surface of cotton leaves with the phytopathogenic bacterium Xanthomonas campestris pv. malvacearum. The inoculum consisted of 2 to 3 × 107 CFU/ml in CaCO3-saturated sterile distilled water containing 0.02%, vol/vol, of the wetting agent Silwet L-77. A custom-made inoculation apparatus was employed to immerse a circular area of the adaxial surface of a leaf in inoculum for 90 s. This resulted in uniform, passive entry of bacteria into the substomatal chambers, producing an endophytic bacterial population of 2 × 104 CFU/cm2. Microscopic signs of infection were visible 48 to 72 h after inoculation. In susceptible leaves, uniformly distributed water-soaked spots were observed 7 to 8 days after inoculation. When the technique was used on resistant leaves, the autofluorescence that is characteristic of hypersensitively necrotic cells developed in the guard cells and palisade cells lining substomatal chambers, but not in the underlying spongy mesophyll.

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