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

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.

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

International Journal of Molecular Sciences ◽

10.3390/ijms22115932 ◽

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.

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

Journal of Bacteriology ◽

10.1128/jb.00143-10 ◽

2010 ◽

Vol 192 (13) ◽

pp. 3484-3490 ◽

Cited By ~ 23

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.

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

Microbiology ◽

10.1099/mic.0.074484-0 ◽

2014 ◽

Vol 160 (4) ◽

pp. 766-777 ◽

Cited By ~ 7

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.

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Effect offurmutation on acid-tolerance response and in vivo virulence of avian septicemicEscherichia coli

Canadian Journal of Microbiology ◽

10.1139/w02-042 ◽

2002 ◽

Vol 48 (5) ◽

pp. 458-462 ◽

Cited By ~ 10

Author(s):

Chengru Zhu ◽

Musangu Ngeleka ◽

Andrew A Potter ◽

Brenda J Allan

Keyword(s):

Parent Strain ◽

Acid Tolerance ◽

Wild Type ◽

Acid Tolerance Response ◽

E Coli ◽

Regulator Protein ◽

In The Wild ◽

Tolerance Response ◽

Wild Type Parent

The Fur (ferric uptake regulator) protein is a master regulator of iron metabolism in gram-negative bacteria. In the present study, the effect of a partial deletion of the fur gene on the acid-tolerance response and in vivo virulence of avian Escherichia coli was examined. The fur mutant was unable to trigger the acid-tolerance response as observed in the wild-type parent strain. However, the mutant was as virulent as the wild-type parent strain when tested in 1-day-old chickens by subcutaneous inoculation. These data indicate that the fur gene is involved in the acid-tolerance response but not involved in the virulence of E. coli, as detected by the ability to cause septicemia in our experimental infection.Key words: E. coli, fur, acid-tolerance response.

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Kemampuan Bakteri Endofit Akar dan Ubi Kentang untuk Menekan Penyakit Busuk Lunak (Erwinia carotovora pv. carotovora) pada Ubi

Agrikultura ◽

10.24198/agrikultura.v27i3.10880 ◽

2016 ◽

Vol 27 (3) ◽

Author(s):

Noor Istifadah ◽

Muhamad Salman Umar ◽

Sudarjat Sudarjat ◽

Luciana Djaya

Keyword(s):

Biological Control ◽

Potato Tuber ◽

Endophytic Bacteria ◽

Erwinia Carotovora ◽

Soft Rot ◽

Soft Rot Disease ◽

Post Harvest ◽

Rot Disease

ABSTRACTThe abilities of endophytic bacteria from potato roots and tubers to suppress soft rot disease (Erwinia carotovora pv. carotovora) in potato tuberSoft rot disease caused by Erwinia carotovora pv. carotovora is one of limiting factors in cultivation and post harvest of potato. The eco-friendly control measure that can be developed for controlling the diseases is biological control. Microbes that are potential as biological control agents include endophytic bacteria. This paper discussed the results of study examining the potential of endophytic bacteria isolated from roots and tubers of potato to inhibit the growth of E. carotovora pv. carotovora in vitro and suppress soft rot disease in potato tuber. The results showed that among 24 isolates examined, four isolates of endophytic bacteria (one isolate from potato tuber and three isolates from potato roots) inhibited the growth of E. carotovora pv. carotovora in vitro with inhibition zone 3.5-6.8 mm. In the in vivo test, the isolates inhibited the soft rot disease in potato tuber by 71.5-86.4%. The isolate that tended to show relatively better inhibition in vitro and in vivo was isolate from potato tuber which is CK U3 (Lysinibacillus sp.)Keywords: Biological control, Endophytic bacteria, Post-harvest, Potato, Soft rot diseaseABSTRAKPenyakit busuk lunak yang disebabkan bakteri Erwinia carotovora pv. carotovora, merupakan salah satu kendala dalam budidaya dan pascapanen kentang. Cara pengendalian ramah lingkungan yang dapat dikembangkan untuk menekan penyakit tersebut adalah pengendalian biologi. Kelompok mikroba yang berpotensi sebagi agens pengendali biologi adalah bakteri endofit. Artikel ini mendiskusikan potensi isolat bakteri endofit yang berasal dari ubi dan akar kentang untuk menghambat pertumbuhan bakteri E. carotovora pv. carotovora secara in vitro dan menekan perkembangan penyakit busuk lunak pada ubi kentang. Hasil percobaan menunjukkan bahwa diantara 24 isolat bakteri yang diuji, terdapat empat isolat bakteri endofit (satu isolat dari ubi kentang dan tiga isolat dari akar kentang) yang dapat menghambat pertumbuhan bakteri E. carotovora pv. carotovora secara in vitro dengan zona penghambatan sebesar 3,5-6,8 mm. Pada pengujian secara in vivo, isolat-isolat tersebut dapat menekan perkembangan penyakit busuk lunak pada ubi kentang sebesar 71,5-86,4%. Isolat yang cenderung menunjukkan penghambatan relatif lebih baik secara in vitro dan in vivo adalah isolat bakteri endofit asal ubi kentang yaitu isolat CK U3 (Lysinibacillus sp.).Kata Kunci: Pengendalian biologi, Bakteri endofit, Pascapanen, Kentang, Penyakit busuk basah

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

Microorganisms ◽

10.3390/microorganisms8050697 ◽

2020 ◽

Vol 8 (5) ◽

pp. 697 ◽

Cited By ~ 1

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.

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

Biomolecules ◽

10.3390/biom9120863 ◽

2019 ◽

Vol 9 (12) ◽

pp. 863 ◽

Cited By ~ 7

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.

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

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d201037 ◽

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.

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Impact of Pre- and Post–Harvest Applications of Natural Antimicrobial Products on Apple and Pear Soft Rot Disease

International Journal of Phytopathology ◽

10.33687/phytopath.004.03.1329 ◽

2016 ◽

Vol 4 (3) ◽

pp. 105-119

Author(s):

Abdelradi T. Bakeer ◽

Khaled Elbanna ◽

Sameh A. Elnaggar

Keyword(s):

Antibacterial Activity ◽

Plant Extracts ◽

Antimicrobial Agents ◽

Soft Rot ◽

Natural Antimicrobial ◽

Soft Rot Disease ◽

Post Harvest ◽

Rot Disease ◽

Bacillus Strains

Three natural antibacterial compounds including bacteriocin like substance (BLS) produced from lactic acid bacteria (LAB), ethanolic extract of propolis (EEP), and nine plant extracts were evaluated against soft rot Bacillus strains. Testing in vivo these compounds were evaluated to control pear and apple soft rot disease. Among eight BLS tested, BLS of LAB2, LAB105 and LAB 107 exhibited the highest antibacterial activity as indicated by the formation of clear inhibition zone. Propolis extracts exhibited significant antibacterial activity against all tested soft rot Bacillus strains and it was noticed that the antibacterial activity was concentration dependent. Among nine plant extracts tested, extracts of Eucalyptus globulus and Psidium guajava exhibited the highest antibacterial activity. All tested antibacterial products significantly decreased apple and pear soft rot severity caused by Bacillus altitudinis compared to untreated control. The highest reduction percentage of soft rot severity was recorded for EEP followed by BLS from LAB and plant extracts tested, respectively. Combined pre-and post-harvest treatments of apple and pear with antimicrobial compounds proved to be more effective in reducing the soft rot severity and improved the physical and chemical properties of fruits during storage in both years of the study. The natural antimicrobial agents used in this study were promising compounds, since it seems to be more safe, economical and great potential for extending the shelf life and improve the quality of fruits. Therefore, the application of these compounds in the control of apple and pear soft rot could be advantageous for consumers, producers, and the environment.

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Genome-wide identification of genes important for growth of Dickeya dadantii and D. dianthicola in potato (Solanum tuberosum) tubers

10.1101/2021.09.16.460530 ◽

2021 ◽

Author(s):

Tyler C. Helmann ◽

Melanie J. Filiatrault ◽

Paul V. Stodghill

Keyword(s):

Solanum Tuberosum ◽

Bacterial Growth ◽

Soft Rot ◽

Competitive Growth ◽

In Planta ◽

Bacterial Strains ◽

Dickeya Dadantii ◽

Genome Wide

AbstractDickeya species are causal agents of soft rot diseases in many economically important crops, including soft rot disease of potato (Solanum tuberosum). Using random barcode transposon-site sequencing (RB-TnSeq), we generated genome-wide mutant fitness profiles of Dickeya dadantii 3937, Dickeya dianthicola ME23, and Dickeya dianthicola 67-19 isolates collected after passage through several in vitro and in vivo conditions. Tubers from the potato cultivars “Atlantic”, “Dark Red Norland”, and “Upstate Abundance” provided highly similar conditions for bacterial growth. Using the homolog detection software PyParanoid, we matched fitness values for orthologous genes in the three bacterial strains. Direct comparison of fitness among the strains highlighted shared and variable traits important for growth. Bacterial growth in minimal medium required many metabolic traits that were also essential for competitive growth in planta, such as amino acid, carbohydrate, and nucleotide biosynthesis. Growth in tubers specifically required the pectin degradation gene kduD. Disruption in three putative DNA-binding proteins had strain-specific effects on competitive fitness in tubers. Though the Soft Rot Pectobacteriaceae can cause disease with little host specificity, it remains to be seen the extent to which strain-level variation impacts virulence.

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