scholarly journals Inactivation of pecS restores the virulence of mutants devoid of osmoregulated periplasmic glucans in the phytopathogenic bacterium Dickeya dadantii

Microbiology ◽  
2014 ◽  
Vol 160 (4) ◽  
pp. 766-777 ◽  
Author(s):  
Sébastien Bontemps-Gallo ◽  
Edwige Madec ◽  
Jean-Marie Lacroix
Keyword(s):  
Plant Cell Wall ◽  
Transcriptional Regulator ◽  
Soft Rot ◽  
Cellular Functions ◽  
Cell Wall Degrading Enzymes ◽  
Dickeya Dadantii ◽  
Phytopathogenic Bacterium ◽  
Wide Range ◽  
Severe Reduction ◽  
Rot Disease

Dickeya dadantii is a phytopathogenic enterobacterium that causes soft rot disease in a wide range of plant species. Maceration, an apparent symptom of the disease, is the result of the synthesis and secretion of a set of plant cell wall-degrading enzymes (PCWDEs), but many additional factors are required for full virulence. Among these, osmoregulated periplasmic glucans (OPGs) and the PecS transcriptional regulator are essential virulence factors. Several cellular functions are controlled by both OPGs and PecS. Strains devoid of OPGs display a pleiotropic phenotype including total loss of virulence, loss of motility and severe reduction in the synthesis of PCWDEs. PecS is one of the major regulators of virulence in D. dadantii, acting mainly as a repressor of various cellular functions including virulence, motility and synthesis of PCWDEs. The present study shows that inactivation of the pecS gene restored virulence in a D. dadantii strain devoid of OPGs, indicating that PecS cannot be de-repressed in strains devoid of OPGs.

scholarly journals A secreted metal-binding protein protects necrotrophic phytopathogens from reactive oxygen species

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Lulu Liu ◽  
Virginie Gueguen-Chaignon ◽  
Isabelle R Gonçalves ◽  
Christine Rascle ◽  
Martine Rigault ◽  
...  
Keyword(s):  
Metal Binding ◽  
Plant Cell Wall ◽  
Metal Accumulation ◽  
Cell Wall Degrading Enzymes ◽  
Dickeya Dadantii ◽  
Phytopathogenic Bacterium ◽  
Gram Positive Bacteria ◽  
Plant Infection ◽  
Ros Formation ◽  
Iron Binding Proteins

Abstract Few secreted proteins involved in plant infection common to necrotrophic bacteria, fungi and oomycetes have been identified except for plant cell wall-degrading enzymes. Here we study a family of iron-binding proteins that is present in Gram-negative and Gram-positive bacteria, fungi, oomycetes and some animals. Homolog proteins in the phytopathogenic bacterium Dickeya dadantii (IbpS) and the fungal necrotroph Botrytis cinerea (BcIbp) are involved in plant infection. IbpS is secreted, can bind iron and copper, and protects the bacteria against H2O2-induced death. Its 1.7 Å crystal structure reveals a classical Venus Fly trap fold that forms dimers in solution and in the crystal. We propose that secreted Ibp proteins binds exogenous metals and thus limit intracellular metal accumulation and ROS formation in the microorganisms.

scholarly journals Increased phosphorylation of the RcsB regulator of the RcsCDB phosphorelay in strains of Dickeya dadantii devoid of osmoregulated periplasmic glucans revealed by Phos-tag gel analysis

Microbiology ◽  
2014 ◽  
Vol 160 (12) ◽  
pp. 2763-2770 ◽  
Author(s):  
Edwige Madec ◽  
Sébastien Bontemps-Gallo ◽  
Jean-Marie Lacroix
Keyword(s):  
Direct Analysis ◽  
Soft Rot ◽  
Dickeya Dadantii ◽  
Constitutive Activation ◽  
Pleiotropic Phenotype ◽  
Regulator Protein ◽  
Wide Range ◽  
In The Wild ◽  
Rot Disease

Osmoregulated periplasmic glucans (OPGs) are general constituents of many proteobacteria. OPGs are important factors required for full virulence in many pathogens including Dickeya dadantii. D. dadantii causes the soft-rot disease in a wide range of plant species. The pleiotropic phenotype of opg-negative strains includes total loss of virulence and motility, and is linked to the constitutive activation of the RcsCDB phosphorelay, deduced from expression analysis of genes of the RcsCDB regulon. The constitutive activation of the RcsCDB phosphorelay in an opg-negative strain was demonstrated by direct analysis of the phosphorylation level of the RcsB regulator protein in vivo by using a Phos-tag retardation gel approach, and was correlated with the phenotype and the expression of motility genes. Data revealed a low level of RcsB phosphorylated form in the wild-type strain and a slight increase of phosphorylation in opgG mutant strains sufficient to induce the pleiotropic phenotype observed.

scholarly journals Identification of Three Type II Toxin-Antitoxin Systems in Model Bacterial Plant Pathogen Dickeya dadantii 3937

2021 ◽  
Vol 22 (11) ◽  
pp. 5932
Author(s):  
Lidia Boss ◽  
Marcin Górniak ◽  
Alicja Lewańczyk ◽  
Joanna Morcinek-Orłowska ◽  
Sylwia Barańska ◽  
...  
Keyword(s):  
Soft Rot ◽  
Type Ii ◽  
Experimental Proof ◽  
Dickeya Dadantii ◽  
Genetic Elements ◽  
Bacterial Cell Death ◽  
Wide Range ◽  
Rot Disease

Type II toxin-antitoxin (TA) systems are genetic elements usually encoding two proteins: a stable toxin and an antitoxin, which binds the toxin and neutralizes its toxic effect. The disturbance in the intracellular toxin and antitoxin ratio typically leads to inhibition of bacterial growth or bacterial cell death. Despite the fact that TA modules are widespread in bacteria and archaea, the biological role of these systems is ambiguous. Nevertheless, a number of studies suggests that the TA modules are engaged in such important processes as biofilm formation, stress response or virulence and maintenance of mobile genetic elements. The Dickeya dadantii 3937 strain serves as a model for pathogens causing the soft-rot disease in a wide range of angiosperm plants. Until now, several chromosome-encoded type II TA systems were identified in silico in the genome of this economically important bacterium, however so far only one of them was experimentally validated. In this study, we investigated three putative type II TA systems in D. dadantii 3937: ccdAB2Dda, phd-docDda and dhiTA, which represents a novel toxin/antitoxin superfamily. We provide an experimental proof for their functionality in vivo both in D. dadantii and Escherichia coli. Finally, we examined the prevalence of those systems across the Pectobacteriaceae family by a phylogenetic analysis.

scholarly journals The Virulence of a Dickeya dadantii 3937 Mutant Devoid of Osmoregulated Periplasmic Glucans Is Restored by Inactivation of the RcsCD-RcsB Phosphorelay

2010 ◽  
Vol 192 (13) ◽  
pp. 3484-3490 ◽  
Author(s):  
Franck Bouchart ◽  
Gilles Boussemart ◽  
Anne-France Prouvost ◽  
Virginie Cogez ◽  
Edwige Madec ◽  
...  
Keyword(s):  
Plant Species ◽  
Soft Rot ◽  
Dickeya Dadantii ◽  
Soft Rot Disease ◽  
Low Level ◽  
Pleiotropic Phenotype ◽  
Wide Range ◽  
Induced Mutagenesis ◽  
Rot Disease ◽  
High Level

ABSTRACT Dickeya dadantii is a pectinolytic phytopathogen enterobacterium that causes soft rot disease on a wide range of plant species. The virulence of D. dadantii involves several factors, including the osmoregulated periplasmic glucans (OPGs) that are general constituents of the envelope of proteobacteria. In addition to the loss of virulence, opg-negative mutants display a pleiotropic phenotype, including decreased motility and increased exopolysaccharide synthesis. A nitrosoguanidine-induced mutagenesis was performed on the opgG strain, and restoration of motility was used as a screen. The phenotype of the opg mutant echoes that of the Rcs system: high level activation of the RcsCD-RcsB phosphorelay is needed to activate exopolysaccharide synthesis and to repress motility, while low level activation is required for virulence in enterobacteria. Here, we show that mutations in the RcsCDB phosphorelay system restored virulence and motility in a D. dadantii opg-negative strain, indicating a relationship between the Rcs phosphorelay and OPGs.

scholarly journals Tricarboxylic Acid (TCA) Cycle Enzymes and Intermediates Modulate Intracellular Cyclic di-GMP Levels and the Production of Plant Cell Wall–Degrading Enzymes in Soft Rot Pathogen Dickeya dadantii

2020 ◽  
Vol 33 (2) ◽  
pp. 296-307 ◽  
Author(s):  
Xiaochen Yuan ◽  
Quan Zeng ◽  
Jingsheng Xu ◽  
Geoffrey B. Severin ◽  
Xiang Zhou ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Tca Cycle ◽  
Soft Rot ◽  
Tricarboxylic Acid ◽  
Dickeya Dadantii ◽  
Tca Cycle Enzymes ◽  
Wide Range ◽  
Transposon Mutants

Dickeya dadantii is a plant-pathogenic bacterium that causes soft-rot in a wide range of plants. Although we have previously demonstrated that cyclic bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP), a bacterial secondary messenger, plays a central role in virulence regulation in D. dadantii, the upstream signals that modulate c-di-GMP remain enigmatic. Using a genome-wide transposon mutagenesis approach of a Δhfq mutant strain that has high c-di-GMP and reduced motility, we uncovered transposon mutants that recovered the c-di-GMP-mediated repression on swimming motility. A number of these mutants harbored transposon insertions in genes encoding tricarboxylic acid (TCA) cycle enzymes. Two of these TCA transposon mutants were studied further by generating chromosomal deletions of the fumA gene (encoding fumarase) and the sdhCDAB operon (encoding succinate dehydrogenase). Disruption of the TCA cycle in these deletion mutants resulted in reduced intracellular c-di-GMP and enhanced production of pectate lyases (Pels), a major plant cell wall–degrading enzyme (PCWDE) known to be transcriptionally repressed by c-di-GMP. Consistent with this result, addition of TCA cycle intermediates such as citrate also resulted in increased c-di-GMP levels and decreased production of Pels. Additionally, we found that a diguanylate cyclase GcpA was solely responsible for the observed citrate-mediated modulation of c-di-GMP. Finally, we demonstrated that addition of citrate induced not only an overproduction of GcpA protein but also a concomitant repression of the c-di-GMP-degrading phosphodiesterase EGcpB which, together, resulted in an increase in the intracellular concentration of c-di-GMP. In summary, our report demonstrates that bacterial respiration and respiration metabolites serve as signals for the regulation of c-di-GMP signaling.

scholarly journals The Ribosomal Protein RplY Is Required for Pectobacterium carotovorum Virulence and Is Induced by Zantedeschia elliotiana Extract

2017 ◽  
Vol 107 (11) ◽  
pp. 1322-1330 ◽  
Author(s):  
Huan Jiang ◽  
Mengyi Jiang ◽  
Liuke Yang ◽  
Peiyan Yao ◽  
Lin Ma ◽  
...  
Keyword(s):  
Plant Extract ◽  
Plant Cell Wall ◽  
Insertion Site ◽  
Bacterial Pathogen ◽  
Soft Rot ◽  
Kanamycin Resistance ◽  
Pectobacterium Carotovorum ◽  
Promoter Trap ◽  
Carotovorum Subsp ◽  
Rot Disease

Pectobacterium carotovorum subsp. carotovorum strain PccS1, a bacterial pathogen causing soft rot disease of Zantedeschia elliotiana (colored calla), was investigated for virulence genes induced by the host plant. Using a promoter-trap transposon (mariner), we obtained 500 transposon mutants showing kanamycin resistance dependent on extract of Z. elliotiana. One of these mutants, PM86, exhibited attenuated virulence on both Z. elliotiana and Brassica rapa subsp. pekinensis. The growth of PM86 was also reduced in minimal medium (MM), and the reduction was restored by adding plant extract to the MM. The gene containing the insertion site was identified as rplY. The deletion mutant ΔrplY, exhibited reduced virulence, motility and plant cell wall-degrading enzyme production but not biofilm formation. Analysis of gene expression and reporter fusions revealed that the rplY gene in PccS1 is up-regulated at both the transcriptional and the translational levels in the presence of plant extract. Our results suggest that rplY is induced by Z. elliotiana extract and is crucial for virulence in P. carotovorum subsp. carotovorum.

scholarly journals Screening, Identification and Efficacy Evaluation of Antagonistic Bacteria for Biocontrol of Soft Rot Disease Caused by Dickeya zeae

2020 ◽  
Vol 8 (5) ◽  
pp. 697 ◽  
Author(s):  
Jieling Li ◽  
Ming Hu ◽  
Yang Xue ◽  
Xia Chen ◽  
Guangtao Lu ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Prevention And Control ◽  
Pathogenic Bacteria ◽  
Soft Rot ◽  
Antagonistic Bacteria ◽  
Bacterial Soft Rot ◽  
Soft Rot Disease ◽  
Wide Range ◽  
Rot Disease ◽  
And Control

Dickeya zeae is the causal agent of bacterial soft rot disease, with a wide range of hosts all over the world. At present, chemical agents, especially agricultural antibiotics, are commonly used in the prevention and control of bacterial soft rot, causing the emergence of resistant pathogens and therefore increasing the difficulty of disease prevention and control. This study aims to provide a safer and more effective biocontrol method for soft rot disease caused by D. zeae. The spot-on-lawn assay was used to screen antagonistic bacteria, and three strains including SC3, SC11 and 3-10 revealed strong antagonistic effects and were identified as Pseudomonas fluorescens, P. parafulva and Bacillus velezensis, respectively, using multi-locus sequence analysis (MLSA) based on the sequences of 16S rRNA and other housekeeping genes. In vitro antimicrobial activity showed that two Pseudomonas strains SC3 and SC11 were only antagonistic to some pathogenic bacteria, while strain 3-10 had broad-spectrum antimicrobial activity on both pathogenic bacteria and fungi. Evaluation of control efficacy in greenhouse trials showed that they all restrained the occurrence and development of soft rot disease caused by D. zeae MS2 or EC1. Among them, strain SC3 had the most impressive biocontrol efficacy on alleviating the soft rot symptoms on both monocotyledonous and dicotyledonous hosts, and strain 3-10 additionally reduced the occurrence of banana wilt disease caused by Fusarium oxysporum f. sp. cubensis. This is the first report of P. fluorescens, P. parafulva and B. velezensis as potential bio-reagents on controlling soft rot disease caused by D. zeae.

scholarly journals Lemon-Fruit-Based Green Synthesis of Zinc Oxide Nanoparticles and Titanium Dioxide Nanoparticles against Soft Rot Bacterial Pathogen Dickeya dadantii

Biomolecules ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 863 ◽  
Author(s):  
Afsana Hossain ◽  
Yasmine Abdallah ◽  
Md. Arshad Ali ◽  
Md. Mahidul Islam Masum ◽  
Bin Li ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Zinc Oxide Nanoparticles ◽  
Titanium Dioxide Nanoparticles ◽  
Soft Rot ◽  
Antibacterial Activities ◽  
Oxide Nanoparticles ◽  
Fruit Extract ◽  
Dickeya Dadantii ◽  
Lemon Fruit ◽  
Rot Disease

Edible plant fruits are safe raw materials free of toxicants and rich in biomolecules for reducing metal ions and stabilizing nanoparticles. Zinc oxide nanoparticles (ZnONPs) and titanium dioxide nanoparticles (TiO2NPs) are the most produced consumer nanomaterials and have known antibacterial activities but have rarely been used against phytopathogenic bacteria. Here, we synthesized ZnONPs and TiO2NPs simply by mixing ZnO or TiO2 solution with a lemon fruit extract at room temperature and showed their antibacterial activities against Dickeya dadantii, which causes sweet potato stem and root rot disease occurring in major sweet potato planting areas in China. Ultraviolet–visible spectrometry and energy dispersive spectroscopy determined their physiochemical characteristics. Transmission electron microscopy, scanning electron microscopy, and X-ray diffraction spectroscopy revealed the nanoscale size and polymorphic crystalline structures of the ZnONPs and TiO2NPs. Fourier-transform infrared spectroscopy revealed their surface stabilization groups from the lemon fruit extract. In contrast to ZnO and TiO2, which had no antibacterial activity against D. dadantii, ZnONPs and TiO2NPs showed inhibitions on D. dadantii growth, swimming motility, biofilm formation, and maceration of sweet potato tuber slices. ZnONPs and TiO2NPs showed similar extents of antibacterial activities, which increased with the increase of nanoparticle concentrations, and inhibited about 60% of D. dadantii activities at the concentration of 50 µg∙mL−1. The green synthetic ZnONPs and TiO2NPs can be used to control the sweet potato soft rot disease by control of pathogen contamination of seed tubers.

scholarly journals A novel subspecies-specific primer targeting the gyrase B gene for the detection of Pectobacterium carotovorum subsp. brasiliense

2019 ◽  
Vol 20 (10) ◽  
Author(s):  
Tri Joko ◽  
ALAN SOFFAN ◽  
MUHAMMAD SAIFUR ROHMAN
Keyword(s):  
Sequence Data ◽  
Soft Rot ◽  
Pectobacterium Carotovorum ◽  
Specific Primer ◽  
Base Pairs ◽  
Detection And Identification ◽  
Wide Range ◽  
Carotovorum Subsp ◽  
Rot Disease ◽  
The Tropics

Abstract. Joko T, Soffan A, Muhammad Saifur Rohman MS. 2019. A novel subspecies-specific primer targeting the gyrase B gene for the detection of Pectobacterium carotovorum subsp. brasiliense. Biodiversitas 20: 3042-3048. Pectobacterium carotovorum subsp. brasiliense is one of the major causative bacterial pathogens of the soft rot disease in various crops. It has a high virulence and a wide range of hosts in the tropics and the subtropics. Most often, conventional methods are not able to accurately distinguish P. carotovorum subsp. brasiliense from other subspecies. Thus, this study aimed to design a specific gyrase B gene (gyrB) -based primers for the detection and identification of soft rot pathogen. The specific primers design was based on the alignment using gyrB gene sequence data from P. carotovorum subsp. brasiliense and other data from the GenBank. The primers comprised of F-gyr-Pcb (5’-CAC AGG CAC CGC TGG CTG TT-3’) and R-gyr-Pcb (5’-CGT CGT TCC ACT GCA ATG CCA-3’) with an amplicon of 336 base pairs. The specificity of the primers pair was verified both in silico and in polymerase chain reaction (PCR) assays, where the primers could only detect P. carotovorum subsp. brasiliense. Primers’ sensitivity was determined by qualitative PCR with a detection limit of less than 0.5 ng/µL of genomic DNA. Hence, the proposed detection tool can be beneficial to advance further studies on the ecology and epidemiology of soft rot diseases.

scholarly journals Deciphering the Components That Coordinately Regulate Virulence Factors of the Soft Rot Pathogen Dickeya dadantii

2014 ◽  
Vol 27 (10) ◽  
pp. 1119-1131 ◽  
Author(s):  
Xiaogang Wu ◽  
Quan Zeng ◽  
Benjamin J. Koestler ◽  
Christopher M. Waters ◽  
George W. Sundin ◽  
...  
Keyword(s):  
Cell Sorting ◽  
Type Iii Secretion ◽  
Plant Cell Wall ◽  
Pectate Lyase ◽  
Soft Rot ◽  
Defense Responses ◽  
Transcriptional Level ◽  
Dickeya Dadantii ◽  
Periplasmic Glucan ◽  
Insertion Mutations

The bacterial soft rot pathogen Dickeya dadantii utilizes the type III secretion system (T3SS) to suppress host defense responses, and secretes pectate lyase (Pel) to disintegrate the plant cell wall. A transposon mutagenesis fluorescence-activated cell sorting screen was used to identify mutants with altered promoter activities of the T3SS pilus gene hrpA. Several insertion mutations, resulting in changes in hrpA expression, were mapped to a new locus, opgGH, which encodes the gene cluster responsible for osmoregulated periplasmic glucan (OPG) synthesis proteins. Our data showed that OPG was involved in T3SS and Pel regulation by altering the expression of the regulatory small RNA RsmB. Through genome searching, the mechanism of two novel regulatory components, the RcsCD-RcsB phosphorelay and CsrD on OPG and the rsmB gene, was further investigated. The Rcs phosphorelay and OPG inversely regulated rsmB at transcriptional and post-transcriptional levels, respectively. CsrD exhibited dual functionality in T3SS and Pel regulation by manipulating levels of RsmB RNA and cyclic diguanylate monophosphate (c-di-GMP). CsrD positively regulated the promoter activity of the rsmB gene but negatively controlled RsmB RNA at the post-transcriptional level via OpgGH. In addition, CsrD contains both GGDEF and EAL domains but acted as a c-di-GMP phosphodiesterase. When the expression of the csrD gene was induced, CsrD regulated T3SS expression and Pel production through controlling intracellular c-di-GMP levels.

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