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Borowicz M, Krzyżanowska DM, Narajczyk M, Sobolewska M, Rajewska M, Czaplewska P, Węgrzyn K, Czajkowski R. Soft rot pathogen Dickeya dadantii 3937 produces tailocins resembling the tails of Peduovirus P2. Front Microbiol 2023; 14:1307349. [PMID: 38098664 PMCID: PMC10719855 DOI: 10.3389/fmicb.2023.1307349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/14/2023] [Indexed: 12/17/2023] Open
Abstract
Tailocins are nanomolecular machines with bactericidal activity. They are produced by bacteria to contribute to fitness in mixed communities, and hence, they play a critical role in their ecology in a variety of habitats. Here, we characterized the new tailocin produced by Dickeya dadantii strain 3937, a well-characterized member of plant pathogenic Soft Rot Pectobacteriaceae (SRP). Tailocins induced in D. dadantii were ca. 166 nm long tubes surrounded by contractive sheaths with baseplates having tail fibers at one end. A 22-kb genomic cluster involved in their synthesis and having high homology to the cluster coding for the tail of the Peduovirus P2 was identified. The D. dadantii tailocins, termed dickeyocins P2D1 (phage P2-like dickeyocin 1), were resistant to inactivation by pH (3.5-12), temperature (4-50°C), and elevated osmolarity (NaCl concentration: 0.01-1 M). P2D1 could kill a variety of different Dickeya spp. but not any strain of Pectobacterium spp. tested and were not toxic to Caenorhabditis elegans.
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Affiliation(s)
- Marcin Borowicz
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology of UG and MUG, University of Gdańsk, Gdańsk, Poland
| | - Dorota M. Krzyżanowska
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology of UG and MUG, University of Gdańsk, Gdańsk, Poland
| | - Magdalena Narajczyk
- Bioimaging Laboratory, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Marta Sobolewska
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology of UG and MUG, University of Gdańsk, Gdańsk, Poland
| | - Magdalena Rajewska
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology of UG and MUG, University of Gdańsk, Gdańsk, Poland
| | - Paulina Czaplewska
- Laboratory of Mass Spectrometry-Core Facility Laboratories, Intercollegiate Faculty of Biotechnology of UG and MUG, University of Gdańsk, Gdańsk, Poland
| | - Katarzyna Węgrzyn
- Laboratory of Molecular Biology, Intercollegiate Faculty of Biotechnology of UG and MUG, University of Gdańsk, Gdańsk, Poland
| | - Robert Czajkowski
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology of UG and MUG, University of Gdańsk, Gdańsk, Poland
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Hu A, Hu M, Chen S, Xue Y, Tan X, Zhou J. Five Plant Natural Products Are Potential Type III Secretion System Inhibitors to Effectively Control Soft-Rot Disease Caused by Dickeya. Front Microbiol 2022; 13:839025. [PMID: 35273588 PMCID: PMC8901885 DOI: 10.3389/fmicb.2022.839025] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 02/01/2022] [Indexed: 11/23/2022] Open
Abstract
Dickeya zeae, a plant soft-rot pathogen, possesses a type III secretion system (T3SS) as one of the major virulence factors, infecting a wide variety of monocotyledonous and dicotyledonous plants and causing serious losses to the production of economic crops. In order to alleviate the problem of pesticide resistance during bacterial disease treatment, compounds targeting at T3SS have been screened using a hrpA-gfp bioreporter. After screening by Multifunctional Microplate Reader and determining by flow cytometer, five compounds including salicylic acid (SA), p-hydroxybenzoic acid (PHBA), cinnamyl alcohol (CA), p-coumaric acid (PCA), and hydrocinnamic acid (HA) significantly inhibiting hrpA promoter activity without affecting bacterial growth have been screened out. All the five compounds reduced hypersensitive response (HR) on non-host tobacco leaves and downregulated the expression of T3SS, especially the master regulator encoding gene hrpL. Inhibition efficacy of the five compounds against soft rot were also evaluated and results confirmed that the above compounds significantly lessened the soft-rot symptoms caused by Dickeya dadantii 3937 on potato, Dickeya fangzhongdai CL3 on taro, Dickeya oryzae EC1 on rice, and D. zeae MS2 on banana seedlings. Findings in this study provide potential biocontrol agents for prevention of soft-rot disease caused by Dickeya spp.
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Affiliation(s)
| | | | | | | | | | - Jianuan Zhou
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, China
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Separation and quantification of 2-keto-3-deoxy-gluconate (KDG) a major metabolite in pectin and alginate degradation pathways. Anal Biochem 2020; 619:114061. [PMID: 33285123 DOI: 10.1016/j.ab.2020.114061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/27/2020] [Accepted: 11/29/2020] [Indexed: 11/21/2022]
Abstract
A rapid and sensitive High Performance Liquid Chromatography (HPLC) method with photometric and fluorescence detection is developed for routine analysis of 2-Keto-3-deoxy-gluconate (KDG), a catabolite product of pectin and alginate. These polysaccharides are primary-based compounds for biofuel production and for generation of high-value-added products. HPLC is performed, after derivatization of the 2-oxo-acid groups of the metabolite with o-phenylenediamine (oPD), using a linear gradient of trifluoroacetic acid and acetonitrile. Quantification is accomplished with an internal standard method. The gradient is optimized to distinguish KDG from its close structural analogues such as 5-keto-4-deoxyuronate (DKI) and 2,5-diketo-3-deoxygluconate (DKII). The proposed method is simple, highly sensitive and accurate for time course analysis of pectin or alginate degradation.
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Lv M, Hu M, Li P, Jiang Z, Zhang LH, Zhou J. A two-component regulatory system VfmIH modulates multiple virulence traits in Dickeya zeae. Mol Microbiol 2019; 111:1493-1509. [PMID: 30825339 DOI: 10.1111/mmi.14233] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2019] [Indexed: 12/27/2022]
Abstract
Bacterial pathogen Dickeya zeae strain EC1 produces antibiotics-like phytotoxins called zeamines, which are major virulence determinants encoded by the zms gene cluster. In this study, we identified a zeamine-deficient mutant with a Tn5 insertion in a gene designated as vfmI encoding a two-component system (TCS) sensor histidine kinase (HK), which is accompanied by vfmH encoding a response regulator (RR) at the same genetic locus. Domain analysis shows this TCS is analogous to the VfmIH of D. dadantii, with typical characteristics of sensor HK and RR, respectively, and sharing the same operon. Deletion of either vfmI or vfmH resulted in decreased production of zeamines and cell wall degrading enzymes (CWDEs), and alleviated virulence on rice seeds and potato tubers. In D. dadantii 3937, VfmH was shown to bind to the promoters of vfmA and vfmE, while in D. zeae EC1, VfmH could bind to the promoters of vfmA, vfmE and vfmF. RNA-seq analysis of strain EC1 and its vfmH mutant also showed that the TCS positively regulated a range of virulence genes, including zms, T1SS, T2SS, T3SS, T6SS, flagellar and CWDE genes.
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Affiliation(s)
- Mingfa Lv
- Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Ming Hu
- Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Peng Li
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, 571158, China
| | - Zide Jiang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Lian-Hui Zhang
- Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Jianuan Zhou
- Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
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Sepulchre JA, Reverchon S, Gouzé JL, Nasser W. Modeling the bioconversion of polysaccharides in a continuous reactor: A case study of the production of oligogalacturonates by Dickeya dadantii. J Biol Chem 2018; 294:1753-1762. [PMID: 30510137 DOI: 10.1074/jbc.ra118.004615] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 11/30/2018] [Indexed: 11/06/2022] Open
Abstract
In the quest for a sustainable economy of the Earth's resources and for renewable sources of energy, a promising avenue is to exploit the vast quantity of polysaccharide molecules contained in green wastes. To that end, the decomposition of pectin appears to be an interesting target because this polymeric carbohydrate is abundant in many fruit pulps and soft vegetables. To quantitatively study this degradation process, here we designed a bioreactor that is continuously fed with de-esterified pectin (PGA). Thanks to the pectate lyases produced by bacteria cultivated in the vessel, the PGA is depolymerized into oligogalacturonates (UGA), which are continuously extracted from the tank. A mathematical model of our system predicted that the conversion efficiency of PGA into UGA increases in a range of coefficients of dilution until reaching an upper limit where the fraction of UGA that is extracted from the bioreactor is maximized. Results from experiments with a continuous reactor hosting a strain of the plant pathogenic bacterium Dickeya dadantii and in which the dilution coefficients were varied quantitatively validated the predictions of our model. A further theoretical analysis of the system enabled an a priori comparison of the efficiency of eight other pectate lyase-producing microorganisms with that of D. dadantii Our findings suggest that D. dadantii is the most efficient microorganism and therefore the best candidate for a practical implementation of our scheme for the bioproduction of UGA from PGA.
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Affiliation(s)
| | - Sylvie Reverchon
- Université Lyon, Université Claude Bernard Lyon 1, INSA-Lyon, CNRS, UMR5240, Microbiologie, Adaptation, Pathogénie, 10 Rue Raphaël Dubois, F-69622 Villeurbanne, France
| | - Jean-Luc Gouzé
- Université Côte d'Azur, Inria, INRA, CNRS, Sorbonne Université, Biocore team, F-06560 Sophia Antipolis, France
| | - William Nasser
- Université Lyon, Université Claude Bernard Lyon 1, INSA-Lyon, CNRS, UMR5240, Microbiologie, Adaptation, Pathogénie, 10 Rue Raphaël Dubois, F-69622 Villeurbanne, France
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Ossowska K, Czerwicka M, Sledz W, Zoledowska S, Motyka A, Golanowska M, Condemine G, Lojkowska E, Kaczyński Z. The uniform structure of O-polysaccharides isolated from Dickeya solani strains of different origin. Carbohydr Res 2017; 445:40-43. [PMID: 28395253 DOI: 10.1016/j.carres.2017.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/31/2017] [Accepted: 04/01/2017] [Indexed: 10/19/2022]
Abstract
O-polysaccharides were isolated from lipopolysaccharides obtained from four different strains of plant pathogenic bacteria belonging to the species Dickeya solani: two of them were isolated in Poland (IFB0099 and IFB0158), the third in Germany (IFB0223) and the last one, D. solani Type Strain IPO2222, originated from the Netherlands. In addition, the O-polysaccharide of a closely related species D. dadantii strain 3937 was isolated. The purified polysaccharides of the five strains were analyzed using NMR spectroscopy and chemical methods. Sugar and methylation analyses, including absolute configuration assignment, together with NMR data revealed that all O-polysaccharides tested are homopolymers of 6-deoxy-d-altrose (d-6dAlt) the following structure: →2)-β-d-6dAltp-(1→.
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Affiliation(s)
- Karolina Ossowska
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland
| | - Małgorzata Czerwicka
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland
| | - Wojciech Sledz
- Department of Biotechnology, Faculty of Biotechnology University of Gdansk, Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | - Sabina Zoledowska
- Department of Biotechnology, Faculty of Biotechnology University of Gdansk, Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | - Agata Motyka
- Department of Biotechnology, Faculty of Biotechnology University of Gdansk, Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | - Małgorzata Golanowska
- Department of Biotechnology, Faculty of Biotechnology University of Gdansk, Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | - Guy Condemine
- Univ Lyon, Université Lyon 1, INSA de Lyon, CNRS UMR5240 Microbiologie Adaptation et Pathogénie, F-69622, Villeurbanne, France
| | - Ewa Lojkowska
- Department of Biotechnology, Faculty of Biotechnology University of Gdansk, Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | - Zbigniew Kaczyński
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland.
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Potrykus M, Golanowska M, Sledz W, Zoledowska S, Motyka A, Kolodziejska A, Butrymowicz J, Lojkowska E. Biodiversity of Dickeya spp. Isolated from Potato Plants and Water Sources in Temperate Climate. PLANT DISEASE 2016; 100:408-417. [PMID: 30694126 DOI: 10.1094/pdis-04-15-0439-re] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bacteria from the genera Dickeya (formerly Erwinia chrysanthemi) and Pectobacterium (formerly E. carotovora) are the agents of blackleg and soft rot on many important crops. In 2005, Dickeya solani was isolated for the first time in Poland from a symptomatic potato plant. To establish the presence and diversity of Dickeya spp. in Poland, we surveyed potato fields and water sources, including surface waters near potato fields and water from potato-processing facilities and sewage plants. Only D. dianthicola and D. solani were isolated from symptomatic potato, and only D. zeae and D. chrysanthemi were isolated from water sources. The Dickeya spp. isolated from potato formed a relatively homogenous group, while those from water sources were more diverse. To our knowledge, this is the first comprehensive characterization of Dickeya spp. isolated during several years from regions with a temperate climate in Central Europe.
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Affiliation(s)
- Marta Potrykus
- Laboratory of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | - Malgorzata Golanowska
- Laboratory of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | - Wojciech Sledz
- Laboratory of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | - Sabina Zoledowska
- Laboratory of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | - Agata Motyka
- Laboratory of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | - Anna Kolodziejska
- The Central Laboratory of the State Plant Health and Seed Inspection Service, Zwirki i Wigury 73 87-100 Torun, Poland
| | - Janina Butrymowicz
- The Central Laboratory of the State Plant Health and Seed Inspection Service, Zwirki i Wigury 73 87-100 Torun, Poland
| | - Ewa Lojkowska
- Laboratory of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk
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Potrykus M, Golanowska M, Hugouvieux-Cotte-Pattat N, Lojkowska E. Regulators Involved in Dickeya solani Virulence, Genetic Conservation and Functional Variability. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 2015:57-68. [PMID: 27839073 DOI: 10.1094/mpmi-99-99-0003-r.testissue] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Bacteria from the genus Dickeya (formerly Erwinia chrysanthemi) are plant pathogens causing severe diseases in many economically important crops. A majority of the strains responsible for potato disease in Europe belong to a newly identified Dickeya solani species. Although some ecological and epidemiological studies have been carried out, little is known about the regulation of D. solani virulence. The characterization of four D. solani strains indicates significant differences in their virulence on potato although they are genetically similar based on genomic fingerprinting profiles. A phenotypic examination included an analysis of virulence on potato, growth rate in culture, motility, Fe3+ chelation, and pectate lyase, cellulase, protease, biosurfactant and blue pigment production. Mutants of four D. solani strains were constructed by inactivating the genes coding either for one of the main negative regulators of D. dadantii virulence (kdgR, pecS and pecT) or for the synthesis and perception of signaling molecules (expI and expR). Analysis of these mutants indicated that PecS, PecT and KdgR play a similar role in both species, repressing to different degrees the synthesis of virulence factors. The thermoregulator PecT seems to be a major regulator of D. solani virulence. This work also reveals the role of quorum sensing mediated by ExpI and ExpR in D. solani virulence on potato.
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Affiliation(s)
- Marta Potrykus
- 1 Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | - Małgorzata Golanowska
- 1 Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | | | - Ewa Lojkowska
- 1 Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
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Potrykus M, Golanowska M, Hugouvieux-Cotte-Pattat N, Lojkowska E. Regulators Involved in Dickeya solani Virulence, Genetic Conservation and Functional Variability. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 2015:5-16. [PMID: 27839070 DOI: 10.1094/mpmi-99-99-0004-le.testissue] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Bacteria from the genus Dickeya (formerly Erwinia chrysanthemi) are plant pathogens causing severe diseases in many economically important crops. A majority of the strains responsible for potato disease in Europe belong to a newly identified Dickeya solani species. Although some ecological and epidemiological studies have been carried out, little is known about the regulation of D. solani virulence. The characterization of four D. solani strains indicates significant differences in their virulence on potato although they are genetically similar based on genomic fingerprinting profiles. A phenotypic examination included an analysis of virulence on potato, growth rate in culture, motility, Fe3+ chelation, and pectate lyase, cellulase, protease, biosurfactant and blue pigment production. Mutants of four D. solani strains were constructed by inactivating the genes coding either for one of the main negative regulators of D. dadantii virulence (kdgR, pecS and pecT) or for the synthesis and perception of signaling molecules (expI and expR). Analysis of these mutants indicated that PecS, PecT and KdgR play a similar role in both species, repressing to different degrees the synthesis of virulence factors. The thermoregulator PecT seems to be a major regulator of D. solani virulence. This work also reveals the role of quorum sensing mediated by ExpI and ExpR in D. solani virulence on potato.
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Affiliation(s)
- Marta Potrykus
- 1 Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | - Małgorzata Golanowska
- 1 Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | | | - Ewa Lojkowska
- 1 Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
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Potrykus M, Golanowska M, Hugouvieux-Cotte-Pattat N, Lojkowska E. Regulators involved in Dickeya solani virulence, genetic conservation, and functional variability. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:700-11. [PMID: 24625032 DOI: 10.1094/mpmi-09-13-0270-r] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Bacteria from the genus Dickeya (formerly Erwinia chrysanthemi) are plant pathogens causing severe diseases in many economically important crops. A majority of the strains responsible for potato disease in Europe belong to a newly identified Dickeya solani species. Although some ecological and epidemiological studies have been carried out, little is known about the regulation of D. solani virulence. The characterization of four D. solani strains indicates significant differences in their virulence on potato, although they are genetically similar based on genomic fingerprinting profiles. A phenotypic examination included an analysis of virulence on potato; growth rate in culture; motility; Fe3+ chelation; and pectate lyase, cellulase, protease, biosurfactant, and blue pigment production. Mutants of four D. solani strains were constructed by inactivating the genes coding either for one of the main negative regulators of D. dadantii virulence (kdgR, pecS, and pecT) or for the synthesis and perception of signaling molecules (expI and expR). Analysis of these mutants indicated that PecS, PecT, and KdgR play a similar role in both species, repressing, to different degrees, the synthesis of virulence factors. The thermoregulator PecT seems to be a major regulator of D. solani virulence. This work also reveals the role of quorum sensing mediated by ExpI and ExpR in D. solani virulence on potato.
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Conventional and real-time PCRs for detection of Erwinia piriflorinigrans allow its distinction from the fire blight pathogen, Erwinia amylovora. Appl Environ Microbiol 2014; 80:2390-8. [PMID: 24509928 DOI: 10.1128/aem.03626-13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Erwinia piriflorinigrans is a new pathogenic species of the bacterial genus Erwinia that has been described recently in Spain. Accurate detection and identification of E. piriflorinigrans are challenging because its symptoms on pear blossoms are similar to those caused by Erwinia amylovora, the causal agent of fire blight. Moreover, these two species share phenotypic and molecular characteristics. Two specific and sensitive conventional and real-time PCR protocols were developed to identify and detect E. piriflorinigrans and to differentiate it from E. amylovora and other species of this genus. These protocols were based on sequences from plasmid pEPIR37, which is present in all strains of E. piriflorinigrans analyzed. After the stability of the plasmid was demonstrated, the specificities of the protocols were confirmed by the amplification of all E. piriflorinigrans strains tested, whereas 304 closely related pathogenic and nonpathogenic Erwinia strains and microbiota from pear trees were not amplified. In sensitivity assays, 10(3) cells/ml extract were detected in spiked plant material by conventional or real-time PCR, and 10(2) cells/ml were detected in DNA extracted from spiked plant material by real-time PCR. The protocols developed here succeeded in detecting E. piriflorinigrans in 102 out of 564 symptomatic and asymptomatic naturally infected pear samples (flowers, cortex stem tissue, leaves, shoots, and fruitlets), in necrotic Pyracantha sp. blossoms, and in necrotic pear and apple tissues infected with both E. amylovora and E. piriflorinigrans. Therefore, these new tools can be used in epidemiological studies that will enhance our understanding of the life cycle of E. piriflorinigrans in different hosts and plant tissues and its interaction with E. amylovora.
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Crépin A, Barbey C, Beury-Cirou A, Hélias V, Taupin L, Reverchon S, Nasser W, Faure D, Dufour A, Orange N, Feuilloley M, Heurlier K, Burini JF, Latour X. Quorum sensing signaling molecules produced by reference and emerging soft-rot bacteria (Dickeya and Pectobacterium spp.). PLoS One 2012; 7:e35176. [PMID: 22539957 PMCID: PMC3335102 DOI: 10.1371/journal.pone.0035176] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 03/09/2012] [Indexed: 12/30/2022] Open
Abstract
Background Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates. Methodology/Principal Findings Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase. Conclusions/Significance Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also differences in the mechanisms of communication via the diffusible molecules. Our results designate autoinducer-1 lactones as the main targets for a global biocontrol of soft-rot bacteria communications, including those of emerging isolates.
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Affiliation(s)
- Alexandre Crépin
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) - Normandie Université - Université de Rouen EA 4312 - IUT Evreux, Evreux, France
- SIPRE Comité Nord Station de Recherche et de Création Variétale, Bretteville du Grand Caux, France
| | - Corinne Barbey
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) - Normandie Université - Université de Rouen EA 4312 - IUT Evreux, Evreux, France
| | - Amélie Beury-Cirou
- SIPRE Comité Nord Station de Recherche et de Création Variétale, Bretteville du Grand Caux, France
- Institut des Sciences du Végétal (ISV) UPR 2355 - CNRS, Gif-sur-Yvette, France
| | - Valérie Hélias
- Fédération Nationale des Producteurs de Plants de Pomme de Terre (FN3PT), Paris, France
- Institut de Génétique Environnement et Protection des Plantes (IGEPP) UMR 1349 - INRA, Rennes, France
| | - Laure Taupin
- Laboratoire de Biotechnologie et Chimie Marines (LBCM) - Université de Bretagne-Sud EA 3884, Lorient, France
| | - Sylvie Reverchon
- Microbiologie Adaptation et Pathogénie (MAP) UMR 5240 - Université Claude Bernard Lyon 1-INSA-CNRS-Bayer CropScience, Villeurbanne, France
| | - William Nasser
- Microbiologie Adaptation et Pathogénie (MAP) UMR 5240 - Université Claude Bernard Lyon 1-INSA-CNRS-Bayer CropScience, Villeurbanne, France
| | - Denis Faure
- Institut des Sciences du Végétal (ISV) UPR 2355 - CNRS, Gif-sur-Yvette, France
| | - Alain Dufour
- Laboratoire de Biotechnologie et Chimie Marines (LBCM) - Université de Bretagne-Sud EA 3884, Lorient, France
| | - Nicole Orange
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) - Normandie Université - Université de Rouen EA 4312 - IUT Evreux, Evreux, France
| | - Marc Feuilloley
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) - Normandie Université - Université de Rouen EA 4312 - IUT Evreux, Evreux, France
| | - Karin Heurlier
- Department of Food Sciences, University of Nottingham, Sutton Bonington, United Kingdom
| | - Jean-François Burini
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) - Normandie Université - Université de Rouen EA 4312 - IUT Evreux, Evreux, France
| | - Xavier Latour
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) - Normandie Université - Université de Rouen EA 4312 - IUT Evreux, Evreux, France
- * E-mail:
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Crépin A, Beury-Cirou A, Barbey C, Farmer C, Hélias V, Burini JF, Faure D, Latour X. N-acyl homoserine lactones in diverse Pectobacterium and Dickeya plant pathogens: diversity, abundance, and involvement in virulence. SENSORS 2012; 12:3484-97. [PMID: 22737020 PMCID: PMC3376598 DOI: 10.3390/s120303484] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 03/02/2012] [Accepted: 03/06/2012] [Indexed: 11/16/2022]
Abstract
Soft-rot bacteria Pectobacterium and Dickeya use N-acyl homoserine lactones (NAHSLs) as diffusible signals for coordinating quorum sensing communication. The production of NAHSLs was investigated in a set of reference strains and recently-collected isolates, which belong to six species and share the ability to infect the potato host plant. All the pathogens produced different NAHSLs, among which the 3-oxo-hexanoyl- and the 3-oxo-octanoyl-l-homoserine lactones represent at least 90% of total produced NAHSL-amounts. The level of NAHSLs varied from 0.6 to 2 pg/cfu. The involvement of NAHSLs in tuber maceration was investigated by electroporating a quorum quenching vector in each of the bacterial pathogen strains. All the NAHSL-lactonase expressing strains produced a lower amount of NAHSLs as compared to those harboring the empty vector. Moreover, all except Dickeya dadantii 3937 induced a lower level of symptoms in potato tuber assay. Noticeably, aggressiveness appeared to be independent of both nature and amount of produced signals. This work highlights that quorum sensing similarly contributed to virulence in most of the tested Pectobacterium and Dickeya, even the strains had been isolated recently or during the past decades. Thus, these key regulatory-molecules appear as credible targets for developing anti-virulence strategies against these plant pathogens.
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Affiliation(s)
- Alexandre Crépin
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen EA 4312, IUT Evreux, 55 rue Saint-Germain, Evreux F-27000, France; E-Mails: (A.C.); (C.B.); (C.F.); (J.-F.B.)
- SIPRE—Comité Nord, Station de recherche et de création variétale, Bretteville du Grand Caux F-76110, France; E-Mail:
| | - Amélie Beury-Cirou
- SIPRE—Comité Nord, Station de recherche et de création variétale, Bretteville du Grand Caux F-76110, France; E-Mail:
- Institut des Sciences du Végétal, CNRS UPR2355, Avenue de la Terrasse, Gif-sur-Yvette 91198, France; E-Mail:
| | - Corinne Barbey
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen EA 4312, IUT Evreux, 55 rue Saint-Germain, Evreux F-27000, France; E-Mails: (A.C.); (C.B.); (C.F.); (J.-F.B.)
| | - Christine Farmer
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen EA 4312, IUT Evreux, 55 rue Saint-Germain, Evreux F-27000, France; E-Mails: (A.C.); (C.B.); (C.F.); (J.-F.B.)
| | - Valérie Hélias
- FN3PT, Fédération Nationale des Producteurs de Plants de Pomme de Terre, 43-45 rue de Naples, Paris F-75008, France; E-Mail:
- INRA, UMR 1349 IGEPP, Le Rheu Cedex F-35653, France
| | - Jean-François Burini
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen EA 4312, IUT Evreux, 55 rue Saint-Germain, Evreux F-27000, France; E-Mails: (A.C.); (C.B.); (C.F.); (J.-F.B.)
| | - Denis Faure
- Institut des Sciences du Végétal, CNRS UPR2355, Avenue de la Terrasse, Gif-sur-Yvette 91198, France; E-Mail:
| | - Xavier Latour
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen EA 4312, IUT Evreux, 55 rue Saint-Germain, Evreux F-27000, France; E-Mails: (A.C.); (C.B.); (C.F.); (J.-F.B.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +33-2-3229-1549; Fax: +33-2-3229-1550
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Abderrahmani A, Tapi A, Nateche F, Chollet M, Leclère V, Wathelet B, Hacene H, Jacques P. Bioinformatics and molecular approaches to detect NRPS genes involved in the biosynthesis of kurstakin from Bacillus thuringiensis. Appl Microbiol Biotechnol 2011; 92:571-81. [PMID: 21751008 DOI: 10.1007/s00253-011-3453-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 06/17/2011] [Accepted: 06/19/2011] [Indexed: 11/28/2022]
Abstract
Degenerated primers designed for the detection by polymerase chain reaction of nonribosomal peptide synthetases (NRPS) genes involved in the biosynthesis of lipopeptides were used on genomic DNA from a new isolate of Bacillus thuringiensis CIP 110220. Primers dedicated to surfactin and bacillomycin detection amplified sequences corresponding respectively to the surfactin synthetase operon and to a gene belonging to a new NRPS operon identified in the genome of B. thuringiensis serovar pondicheriensis BSCG 4BA1. A bioinformatics analysis of this operon led to the prediction of an NRPS constituted of seven modules beginning with a condensation starter domain and which could be involved in the biosynthesis of a heptalipopeptide similar to kurstakin. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS) performed on whole cells of B. thuringiensis CIP 110220 confirmed the production of kurstakin by this strain. The kurstakin operon was thus used to design a new set of degenerated primers specifically to detect kurstakin genes. These primers were used to screen kurstakin producers in a collection of nine B. thuringiensis strains isolated from different areas in Algeria and two from the Pasteur Institute collection. For eight among the 11 tested strains, the amplified fragment matched with an operon similar to the kurstakin operon and found in the newly sequenced genome of Bacillus cereus or B. thuringiensis serovar pulsiensis, kurstaki, and thuringiensis. Kurstakin production was detected by MALDI-ToF-MS on whole cells for six strains. This production was compared with the spreading of the strains and their antimicrobial activity. Only the spreading can be correlated with the kurstakin production.
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Affiliation(s)
- Ahmed Abderrahmani
- Laboratoire des Procédés Biologiques, Génie Enzymatique et Microbien, ProBioGEM, UPRES-EA 1026, Polytech'Lille/IUT A, Université Lille Nord de France-Sciences et Technologies, USTL, Avenue Paul Langevin, 59655, Villeneuve d'Ascq Cedex, France
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15
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Kepseu WD, Sepulchre JA, Reverchon S, Nasser W. Toward a quantitative modeling of the synthesis of the pectate lyases, essential virulence factors in Dickeya dadantii. J Biol Chem 2010; 285:28565-76. [PMID: 20581112 PMCID: PMC2937882 DOI: 10.1074/jbc.m110.114710] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 06/16/2010] [Indexed: 12/20/2022] Open
Abstract
A dynamic mathematical model has been developed and validated to describe the synthesis of pectate lyases (Pels), the major virulence factors in Dickeya dadantii. This work focuses on the simultaneous modeling of the metabolic degradation of pectin by Pel enzymes and the genetic regulation of pel genes by 2-keto-3-deoxygluconate (KDG), a catabolite product of pectin that inactivates KdgR, one of the main repressors of pel genes. This modeling scheme takes into account the fact that the system is composed of two time-varying compartments: the extracellular medium, where Pel enzymes cleave pectin into oligomers, and the bacterial cytoplasm where, after internalization, oligomers are converted to KDG. Using the quasi-stationary state approximations, the model consists of some nonlinear differential equations for which most of the parameters could be estimated from the literature or from independent experiments. The few remaining unknown parameters were obtained by fitting the model equations against a set of Pel activity data. Model predictions were verified by measuring the time courses of bacterial growth, Pel production, pel mRNA accumulation, and pectin consumption under various growth conditions. This work reveals that pectin is almost totally consumed before the burst of Pel production. This paradoxical behavior can be interpreted as an evolutionary strategy to control the diffusion process so that as soon as a small amount of pectin is detected by the bacteria in its surroundings, it anticipates more pectin to come. The model also predicts the possibility of bistable steady states in the presence of constant pectin compounds.
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Affiliation(s)
- Wilfred D. Kepseu
- From the Institut Non Linéaire de Nice, University of Nice–Sophia Antipolis, CNRS Unité Mixte de Recherche 6618, 1361 route des Lucioles, 06560 Valbonne, France and
| | - Jacques-Alexandre Sepulchre
- From the Institut Non Linéaire de Nice, University of Nice–Sophia Antipolis, CNRS Unité Mixte de Recherche 6618, 1361 route des Lucioles, 06560 Valbonne, France and
| | - Sylvie Reverchon
- Microbiologie, Adaptation et Pathogénie, Unité Mixte de Recherche 5240 CNRS-Université Claude Bernard Lyon 1–Institut National des Sciences Appliquées–BayerCorpScience, University of Lyon 1, 10 rue Raphael Dubois, 69622 Villeurbanne Cedex, France
| | - William Nasser
- Microbiologie, Adaptation et Pathogénie, Unité Mixte de Recherche 5240 CNRS-Université Claude Bernard Lyon 1–Institut National des Sciences Appliquées–BayerCorpScience, University of Lyon 1, 10 rue Raphael Dubois, 69622 Villeurbanne Cedex, France
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Chatterjee AK, Thurn KK, Feese DA. Tn5-Induced Mutations in the Enterobacterial Phytopathogen Erwinia chrysanthemi. Appl Environ Microbiol 2010; 45:644-50. [PMID: 16346212 PMCID: PMC242338 DOI: 10.1128/aem.45.2.644-650.1983] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli (2492/pJB4JI) matings with Erwinia chrysanthemi produced kanamycin resistant (Km) transconjugants, a majority of which were gentamicin sensitive (Gm). A small proportion (about 0.8%) of the Km Gm clones were either auxotrophic or failed to catabolize galacturonate (Gtu). The R plasmid (pJB4JI) DNA was detected in the parent E. coli strain and in a Km Gm transconjugant, but not in Km GmE. chrysanthemi strains carrying Tn5-induced mutations. In Hfr crosses, Km (Tn5) was found linked with most mutations. A majority (>95%) of prototrophic recombinants were Km, except for Leu and Arg recombinants which were 30 to 50% Km. Spontaneous revertants were obtained for all markers except car, gtu, lys, thr, and trp. Prototrophic revertants, with the exception of Met, Leu, or His clones, were Km. We conclude from both genetic and physical data that Tn5 transposed from pJB4JI into different sites on the chromosome of E. chrysanthemi.
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Affiliation(s)
- A K Chatterjee
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506
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Rodríguez-Sanz M, Antúnez-Lamas M, Rojas C, López-Solanilla E, Palacios JM, Rodríguez-Palenzuela P, Rey L. The Tat pathway of plant pathogen Dickeya dadantii 3937 contributes to virulence and fitness. FEMS Microbiol Lett 2010; 302:151-8. [PMID: 19929966 DOI: 10.1111/j.1574-6968.2009.01844.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Protein secretion plays a very important role in the virulence of the bacterium Dickeya dadantii, the causative agent of soft rot disease, in a wide range of plant species. We studied the contribution of the twin-arginine translocation (Tat) protein system to the adaptation of D. dadantii 3937 to different growth conditions and to the interaction with the plant host. First, a list of 44 putative Tat substrates was obtained using bioinformatic programs taking advantage of the availability of the complete sequence of this bacterium. Second, a tatC mutant strain was constructed and analysed. The mutant displayed a pleiotropic phenotype, showing limited growth in an iron-depleted medium, higher sensitivity to copper, reduced motility on soft agar plates and attenuated virulence in witloof chicory leaves. Our results indicate the Tat system as an important determinant of the virulence and fitness of D. dadantii 3937. Potential Tat substrates related to the tatC mutant phenotype are discussed.
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Affiliation(s)
- Manuel Rodríguez-Sanz
- Departamento de Biotecnología, E.T.S.I. Agrónomos, Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
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18
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Ryan MP, Pembroke JT, Adley CC. Novel Tn4371-ICE like element in Ralstonia pickettii and genome mining for comparative elements. BMC Microbiol 2009; 9:242. [PMID: 19941653 PMCID: PMC2789088 DOI: 10.1186/1471-2180-9-242] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 11/26/2009] [Indexed: 11/22/2022] Open
Abstract
Background Integrative Conjugative Elements (ICEs) are important factors in the plasticity of microbial genomes. An element related to the ICE Tn4371 was discovered during a bioinformatic search of the Ralstonia pickettii 12J genome. This element was analysed and further searches carried out for additional elements. A PCR method was designed to detect and characterise new elements of this type based on this scaffold and a culture collection of fifty-eight Ralstonia pickettii and Ralstonia insidiosa strains were analysed for the presence of the element. Results Comparative sequence analysis of bacterial genomes has revealed the presence of a number of uncharacterised Tn4371-like ICEs in the genomes of several β and γ- Proteobacteria. These elements vary in size, GC content, putative function and have a mosaic-like structure of plasmid- and phage-like sequences which is typical of Tn4371-like ICEs. These elements were found after a through search of the GenBank database. The elements, which are found in Ralstonia, Delftia, Acidovorax, Bordetella, Comamonas, Acidovorax, Congregibacter, Shewanella, Pseudomonas Stenotrophomonas, Thioalkalivibrio sp. HL-EbGR7, Polaromonas, Burkholderia and Diaphorobacter sp. share a common scaffold. A PCR method was designed (based on the Tn4371- like element detected in the Ralstonia pickettii 12J genome) to detect and characterise new elements of this type. Conclusion All elements found in this study possess a common scaffold of core genes but contain different accessory genes. A new uniform nomenclature is suggested for ICEs of the Tn4371 family. Two novel Tn4371-like ICE were discovered and characterised, using the novel PCR method described in two different isolates of Ralstonia pickettii from laboratory purified water.
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Affiliation(s)
- Michael P Ryan
- Microbiology Laboratory, Department of Chemical and Environmental Sciences, University of Limerick, Limerick, Ireland.
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phiEC2, a new generalized transducing phage of Erwinia chrysanthemi. Virology 2008; 137:102-12. [PMID: 18639822 DOI: 10.1016/0042-6822(84)90013-8] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/1984] [Accepted: 05/15/1984] [Indexed: 11/22/2022]
Abstract
A collection of Erwinia strains (chrysanthemi and carotovora) was screened for temperate phages. One of them, phiEC2, turned out to be a generalized transducing phage. The structure of its DNA was found to be 62 kb long, terminally redundant, and circularly permuted. The transducing properties of the phage are also briefly described.
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Lautier T, Nasser W. The DNA nucleoid-associated protein Fis co-ordinates the expression of the main virulence genes in the phytopathogenic bacterium Erwinia chrysanthemi. Mol Microbiol 2007; 66:1474-90. [PMID: 18028311 DOI: 10.1111/j.1365-2958.2007.06012.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Erwinia chrysanthemi strain 3937 is a necrotrophic bacterial plant pathogen. Pectinolytic enzymes and, in particular, pectate lyases (Pels) play a key role in soft rot symptoms but the efficient colonization of plants by E. chrysanthemi requires additional factors. These factors include the harpin HrpN, the cellulase Cel5, proteases (Prts), flagellar proteins and the Sap system, involved in the detoxification of plant antimicrobial peptides. HrpN and flagellum are mostly involved in the early steps of infection whereas the degradative enzymes (Pels, Cel5, Prts) are mainly required in the advanced stages. Production of these virulence factors is tightly regulated by environmental conditions. This report shows that the nucleoid-associated protein Fis plays a pivotal role in the expression of the main virulence genes. Its production is regulated in a growth phase-dependent manner and is under negative autoregulation. An E. chrysanthemi fis mutant displays a reduced motility and expression of hrpN, prtC and the sap operon. In contrast, the expression of the cel5 gene is increased in this mutant. Furthermore, the induction of the Pel activity is delayed and increased during the stationary growth phase in the fis mutant. Most of these controls occur through a direct effect because purified Fis binds to the promoter regions of fis, hrpN, sapA, cel5 and fliC. Moreover, potassium permanganate footprinting and in vitro transcription assays have revealed that Fis prevents transcription initiation at the fis promoter and also transcript elongation from the cel5 promoter. Finally, the fis mutant has a decreased virulence. These results suggest a co-ordinated regulation by Fis of virulence factors involved in certain key steps of infection, early (asymptomatic) and advanced (symptomatic) phases.
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Affiliation(s)
- Thomas Lautier
- Université de Lyon, F-69003, France; Université Lyon 1, F-69622, France; INSA-Lyon, Villeurbanne, F-69621, France; CNRS, UMR 5240, Unité Microbiologie Adaptation et Pathogénie, F-69622, France
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Venkatesh B, Babujee L, Liu H, Hedley P, Fujikawa T, Birch P, Toth I, Tsuyumu S. The Erwinia chrysanthemi 3937 PhoQ sensor kinase regulates several virulence determinants. J Bacteriol 2006; 188:3088-98. [PMID: 16585768 PMCID: PMC1447017 DOI: 10.1128/jb.188.8.3088-3098.2006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The PhoPQ two-component system regulates virulence factors in Erwinia chrysanthemi, a pectinolytic enterobacterium that causes soft rot in several plant species. We characterized the effect of a mutation in phoQ, the gene encoding the sensor kinase PhoQ of the PhoPQ two-component regulatory system, on the global transcriptional profile of E. chrysanthemi using cDNA microarrays and further confirmed our results by quantitative reverse transcription-PCR analysis. Our results indicate that a mutation in phoQ affects transcription of at least 40 genes, even in the absence of inducing conditions. Enhanced expression of several genes involved in iron metabolism was observed in the mutant, including that of the acs operon that is involved in achromobactin biosynthesis and transport. This siderophore is required for full virulence of E. chrysanthemi, and its expression is governed by the global repressor protein Fur. Changes in gene expression were also observed for membrane transporters, stress-related genes, toxins, and transcriptional regulators. Our results indicate that the PhoPQ system governs the expression of several additional virulence factors and may also be involved in interactions with other regulatory systems.
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Affiliation(s)
- Balakrishnan Venkatesh
- Laboratory of Plant Pathology, Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-Ku, Shizuoka 422-8529, Japan
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Nasser W, Reverchon S, Vedel R, Boccara M. PecS and PecT coregulate the synthesis of HrpN and pectate lyases, two virulence determinants in Erwinia chrysanthemi 3937. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:1205-14. [PMID: 16353555 DOI: 10.1094/mpmi-18-1205] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Erwinia chrysanthemi strain 3937 is a necrotrophic bacterial plant pathogen. Pectinolytic enzymes and, in particular, pectate lyases play a key role in soft rot symptoms; however, the efficient colonization of plants by E. chrysanthemi requires additional factors. These factors include HrpN (harpin), a heat-stable, glycine-rich hydrophilic protein, which is secreted by the type III secretion system. We investigated the expression of hrpN in E. chrysanthemi 3937 in various environmental conditions and different regulatory backgrounds. Using lacZ fusions, hrpN expression was markedly influenced by the carbon source, osmolarity, growth phase, and growth substrate. hrpN was repressed when pectinolysis started and negatively regulated by the repressors of pectate lyase synthesis, PecS and PecT. Primer extension data and in vitro DNA-protein interaction experiments support a model whereby PecS represses hrpN expression by binding to the hrpN regulatory region and inhibiting transcript elongation. The results suggest coordinated regulation of HrpN and pectate lyases by PecS and PecT. A putative model of the synthesis of these two virulence factors in E. chrysanthemi during pathogenesis is presented.
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Affiliation(s)
- William Nasser
- Unité de Microbiologie et Génétique UMR CNRS-INSA-UCBL 5122 Domaine Scientifique de la Doua, Université Claude Bernard Lyon I Bâtiment A Lwoff, Villeurbanne, France.
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Llama-Palacios A, López-Solanilla E, Rodríguez-Palenzuela P. Role of the PhoP-PhoQ system in the virulence of Erwinia chrysanthemi strain 3937: involvement in sensitivity to plant antimicrobial peptides, survival at acid Hh, and regulation of pectolytic enzymes. J Bacteriol 2005; 187:2157-62. [PMID: 15743964 PMCID: PMC1064042 DOI: 10.1128/jb.187.6.2157-2162.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Accepted: 12/10/2004] [Indexed: 11/20/2022] Open
Abstract
Erwinia chrysanthemi is a phytopathogenic bacterium that causes soft-rot diseases in a broad number of crops. The PhoP-PhoQ system is a key factor in pathogenicity of several bacteria and is involved in the bacterial resistance to different factors, including acid stress. Since E. chrysanthemi is confronted by acid pH during pathogenesis, we have studied the role of this system in the virulence of this bacterium. In this work, we have isolated and characterized the phoP and phoQ mutants of E. chrysanthemi strain 3937. It was found that: (i) they were not altered in their growth at acid pH; (ii) the phoQ mutant showed diminished ability to survive at acid pH; (iii) susceptibility to the antimicrobial peptide thionin was increased; (iv) the virulence of the phoQ mutant was diminished at low and high magnesium concentrations, whereas the virulence of the phoP was diminished only at low magnesium concentrations; (v) in planta Pel activity of both mutant strains was drastically reduced; and (vi) both mutants lagged behind the wild type in their capacity to change the apoplastic pH. These results suggest that the PhoP-PhoQ system plays a role in the virulence of this bacterium in plant tissues, although it does not contribute to bacterial growth at acid pH.
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Gloux K, Touze T, Pagot Y, Jouan B, Blanco C. Mutations of ousA alter the virulence of Erwinia chrysanthemi. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:150-157. [PMID: 15720084 DOI: 10.1094/mpmi-18-0150] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A negative correlation was observed between the aggressiveness of several Erwinia chrysanthemi strains on potato tuber and their osmotic tolerance. The disruption of the ousA gene encoding the major osmoprotectant uptake system highly enhanced bacterial virulence on potato tubers. The ousA disruption also increased the maceration efficiency on potato tubers under anaerobic conditions. In the absence of oxygen, pectate lyase (Pel) production was significantly higher in the tissue macerated with the ousA- strain than with the wild type. Oxygen content is significantly different between infected and healthy tissues; therefore, ousA may be a contributory factor in the infection progression within the host. In minimal medium, ousA disruption enhanced Pel production and pelE expression only under micro-aerobiosis conditions. The effect on Pel was reversed by reintroduction of the ousA gene. The osmoprotectectants glycine betaine, proline betaine, and pipecolic acid are known to be taken up via OusA and to have an inhibitory effect on Pel production. However, their effects on Pel activity were not (glycine betaine) or only weakly (proline and pipecolic acid) affected by ousA disruption. Furthermore, no correlation was observed between their effects on Pel activities and their osmoprotection efficacies. The results demonstrate a relationship between E. chrysanthemi pathogenicity factors and the activity of ousA under low oxygen status. The evidence indicates that ousA and osmoprotectant effects on Pel are not linked to osmoregulation and that complex regulations exist between Pel production, ousA, and osmoprotection via compounds liberated during the plant infection.
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Affiliation(s)
- Karine Gloux
- INRA, Unité Mixte de Recherche des Organismes et des Populations appliquée à la Protection des Plantes, Domaine de la motte, 35653 Le Rheu Cedex, France.
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Delmas S, Matic I. Cellular response to horizontally transferred DNA in Escherichia coli is tuned by DNA repair systems. DNA Repair (Amst) 2005; 4:221-9. [PMID: 15590330 DOI: 10.1016/j.dnarep.2004.09.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2004] [Indexed: 10/26/2022]
Abstract
We studied how DNA divergence between recombining DNAs and the mismatch repair system modulate the SOS response in Escherichia coli. The observed positive log-linear correlation between SOS induction and DNA divergence, and the negative correlation between SOS induction and frequency of recombination, suggest that the level of SOS induction precisely reflects the difficulty of RecA protein to initiate a productive strand exchange process. Our results suggest that the mismatch repair system could contribute to this SOS induction more by affecting the RecA-catalyzed homology search than by acting on mismatched recombination intermediates. The propensity of the recombination machinery to promote recombination between the blocks of sequences with the highest identity results in the increasing ratios of merodiploids (partial diploids) over genuine recombinants (homologous replacements) with increasing DNA divergence. We discuss the role of molecular mechanisms involved in the control of the recombination between diverged DNA sequences in the maintenance of genomic stability and genome evolution.
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Affiliation(s)
- Stéphane Delmas
- INSERM U571, Faculté de Médecine Necker-Enfants Malades Université Paris V, 156 rue Vaugirard, 75730 Paris Cedex 15, France
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Goude R, Renaud S, Bonnassie S, Bernard T, Blanco C. Glutamine, glutamate, and alpha-glucosylglycerate are the major osmotic solutes accumulated by Erwinia chrysanthemi strain 3937. Appl Environ Microbiol 2004; 70:6535-41. [PMID: 15528516 PMCID: PMC525223 DOI: 10.1128/aem.70.11.6535-6541.2004] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2004] [Accepted: 07/02/2004] [Indexed: 11/20/2022] Open
Abstract
Erwinia chrysanthemi is a phytopathogenic soil enterobacterium closely related to Escherichia coli. Both species respond to hyperosmotic pressure and to external added osmoprotectants in a similar way. Unexpectedly, the pools of endogenous osmolytes show different compositions. Instead of the commonly accumulated glutamate and trehalose, E. chrysanthemi strain 3937 promotes the accumulation of glutamine and alpha-glucosylglycerate, which is a new osmolyte for enterobacteria, together with glutamine. The amounts of the three osmolytes increased with medium osmolarity and were reduced when betaine was provided in the growth medium. Both glutamine and glutamate showed a high rate of turnover, whereas glucosylglycerate stayed stable. In addition, the balance between the osmolytes depended on the osmolality of the medium. Glucosylglycerate and glutamate were the major intracellular compounds in low salt concentrations, whereas glutamine predominated at higher concentrations. Interestingly, the ammonium content of the medium also influenced the pool of osmolytes. During bacterial growth with 1 mM ammonium in stressing conditions, more glucosylglycerate accumulated by far than the other organic solutes. Glucosylglycerate synthesis has been described in some halophilic archaea and bacteria but not as a dominant osmolyte, and its role as an osmolyte in Erwinia chrysanthemi 3937 shows that nonhalophilic bacteria can also use ionic osmolytes.
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Affiliation(s)
- Renan Goude
- Osmorégulation chez les Bactéries, CNRS UMR 6026, Campus de Beaulieu, Université de Rennes I, Rennes, France
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Matsumoto H, Jitareerat P, Baba Y, Tsuyumu S. Comparative study of regulatory mechanisms for pectinase production by Erwinia carotovora subsp. carotovora and Erwinia chrysanthemi. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2003; 16:226-237. [PMID: 12650454 DOI: 10.1094/mpmi.2003.16.3.226] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The production of pectinase, the major virulence determinant of soft-rot Erwinia species, is controlled by many regulatory factors. We focused on the major regulatory proteins, KdgR, CRP, Pir, and PecS, characterized mainly in E. chrysanthemi, and tested for their presence and function in the control of pectate lyase (Pel) and polygalacturonase (Peh) production in E. carotovora subsp. carotovora. Homologues of kdgR and crp but not of pir and pecS were detected by Southern blot analyses in E. carotovora subsp. carotovora. In fact, KdgR and CRP homologues of E. carotovora subsp. carotovora had high amino acid identities to those of E. chrysanthemi, including a complete match of the hypothetical helix-turn-helix DNA-binding motif. However, in Western blot analyses using anti-Pir (E. chrysanthemi) antibodies, a cross-reacting protein was present in both Erwinia species, although Pel production in E. carotovora subsp. carotovora was not further stimulated by adding plant extract into the medium containing PGA (polygalacturonic acid) in which hyperinduction by Pir has been reported in E. chrysanthemi EC16. When plasmids that contained each of these regulatory genes from E. chrysanthemi were introduced into E. carotovora subsp. carotovora, Pel production was controlled as predicted from their roles in E. chrysanthemi, except for PecS. PecS exerted a positive control in E. carotovora subsp. carotovora, in contrast to a negative control in E. chrysanthemi. DNA-binding assays demonstrated that KdgR, CRP, Pir, and PecS of E. chrysanthemi and KdgR and CRP homologues of E. carotovora subsp. carotovora could bind to the promoter regions of pel-1, pel-3, and peh of E. carotovora subsp. carotovora. Taken together, KdgR and CRP homologues of E. carotovora subsp. carotovora may regulate Pel and Peh production as in E. chrysanthemi. However, the presence of Pir and PecS homologues in E. carotovora subsp. carotovora was not identified in this study, though these proteins of E. chrysanthemi were functional on the promoter regions of the pectinase genes of E. carotovora subsp. carotovora.
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Affiliation(s)
- Hiroyuki Matsumoto
- United Graduate School of Agricultural Science, Gifu University (Shizuoka University), 836 Ohya, Shizuoka 422-8529, Japan
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Reverchon S, Rouanet C, Expert D, Nasser W. Characterization of indigoidine biosynthetic genes in Erwinia chrysanthemi and role of this blue pigment in pathogenicity. J Bacteriol 2002; 184:654-65. [PMID: 11790734 PMCID: PMC139515 DOI: 10.1128/jb.184.3.654-665.2002] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the plant-pathogenic bacterium Erwinia chrysanthemi production of pectate lyases, the main virulence determinant, is modulated by a complex network involving several regulatory proteins. One of these regulators, PecS, also controls the synthesis of a blue pigment identified as indigoidine. Since production of this pigment is cryptic in the wild-type strain, E. chrysanthemi ind mutants deficient in indigoidine synthesis were isolated by screening a library of Tn5-B21 insertions in a pecS mutant. These ind mutations were localized close to the regulatory pecS-pecM locus, immediately downstream of pecM. Sequence analysis of this DNA region revealed three open reading frames, indA, indB, and indC, involved in indigoidine biosynthesis. No specific function could be assigned to IndA. In contrast, IndB displays similarity to various phosphatases involved in antibiotic synthesis and IndC reveals significant homology with many nonribosomal peptide synthetases (NRPS). The IndC product contains an adenylation domain showing the signature sequence DAWCFGLI for glutamine recognition and an oxidation domain similar to that found in various thiazole-forming NRPS. These data suggest that glutamine is the precursor of indigoidine. We assume that indigoidine results from the condensation of two glutamine molecules that have been previously cyclized by intramolecular amide bond formation and then dehydrogenated. Expression of ind genes is strongly derepressed in the pecS background, indicating that PecS is the main regulator of this secondary metabolite synthesis. DNA band shift assays support a model whereby the PecS protein represses indA and indC expression by binding to indA and indC promoter regions. The regulatory link, via pecS, between indigoidine and virulence factor production led us to explore a potential role of indigoidine in E. chrysanthemi pathogenicity. Mutants impaired in indigoidine production were unable to cause systemic invasion of potted Saintpaulia ionantha. Moreover, indigoidine production conferred an increased resistance to oxidative stress, indicating that indigoidine may protect the bacteria against the reactive oxygen species generated during the plant defense response.
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Affiliation(s)
- Sylvie Reverchon
- Unité de Microbiologie et Génétique CNRS-INSA-UCB UMR 5122, INSA, Bâtiment Louis Pasteur, 11 Avenue Jean Capelle, 69621 Villeurbanne Cedex, France.
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Touzé T, Gouesbet G, Boiangiu C, Jebbar M, Bonnassie S, Blanco C. Glycine betaine loses its osmoprotective activity in a bspA strain of Erwinia chrysanthemi. Mol Microbiol 2001; 42:87-99. [PMID: 11679069 DOI: 10.1046/j.1365-2958.2001.02591.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Erwinia chrysanthemi insertion mutants were isolated that grew poorly specifically in the presence of glycine betaine (GB) or its analogues in high-salt media. Transposon insertions were found to affect the bspA gene, which forms an operon including the psd locus coding for phosphatidylserine decarboxylase. Initial GB uptake is not affected by the bspA mutation. However, in high-salt medium, its initial accumulation is followed by a reduced glucose uptake and a release of GB but not a loss of viability. BspA is homologous to the widespread MscS channel, YggB, but does not seem to constitute a mechanosensitive channel. We suggest that BspA is a protein sensing both intracellular GB and the extracellular salt content of the medium, the hypothesis being built on the observation that BspA is necessary to maintain the GB pool during osmoadaptation in high-salt media containing this osmoprotectant.
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Affiliation(s)
- T Touzé
- Osmorégulation chez les bactéries, CNRS UMR 6026, Université de Rennes I, Campus de Beaulieu, Av. du Général Leclerc, 35042 Rennes, France
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Page F, Altabe S, Hugouvieux-Cotte-Pattat N, Lacroix JM, Robert-Baudouy J, Bohin JP. Osmoregulated periplasmic glucan synthesis is required for Erwinia chrysanthemi pathogenicity. J Bacteriol 2001; 183:3134-41. [PMID: 11325942 PMCID: PMC95214 DOI: 10.1128/jb.183.10.3134-3141.2001] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2000] [Accepted: 03/06/2001] [Indexed: 11/20/2022] Open
Abstract
Erwinia chrysanthemi is a phytopathogenic enterobacterium causing soft rot disease in a wide range of plants. Osmoregulated periplasmic glucans (OPGs) are intrinsic components of the gram-negative bacterial envelope. We cloned the opgGH operon of E. chrysanthemi, encoding proteins involved in the glucose backbone synthesis of OPGs, by complementation of the homologous locus mdoGH of Escherichia coli. OpgG and OpgH show a high level of similarity with MdoG and MdoH, respectively, and mutations in the opgG or opgH gene abolish OPG synthesis. The opg mutants exhibit a pleiotropic phenotype, including overproduction of exopolysaccharides, reduced motility, bile salt hypersensitivity, reduced protease, cellulase, and pectate lyase production, and complete loss of virulence. Coinoculation experiments support the conclusion that OPGs present in the periplasmic space of the bacteria are necessary for growth in the plant host.
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Affiliation(s)
- F Page
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR USTL-CNRS 8576, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq Cedex, France
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Enard C, Expert D. Characterization of a tonB mutation in Erwinia chrysanthemi 3937: TonB(Ech) is a member of the enterobacterial TonB family. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 8):2051-2058. [PMID: 10931909 DOI: 10.1099/00221287-146-8-2051] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The pectinolytic enterobacterium Erwinia chrysanthemi 3937 causes a systemic disease in its natural host, the African violet (Saintpaulia: ionantha). It produces two structurally unrelated siderophores, chrysobactin and achromobactin. Chrysobactin makes a large contribution to invasive growth of the bacterium in its host. Insertion mutants of a chrysobactin-defective strain were constructed and screened on the universal CAS-agar medium used for siderophore detection. A set of mutants affected in the production of achromobactin were identified. This paper describes a mutant affected in the transport of all the ferrisiderophores used by the bacterium as iron sources. Molecular analysis revealed that the insertion mutation disrupts the tonB gene. The predicted Er. chrysanthemi TonB protein has a molecular mass of 27600 Da and shares 20-58% identity with the TonB proteins from 20 other bacterial species. The pathogenicity of the tonB mutant was assessed by inoculation of African violets. The impairment in the spread of symptoms was similar in the tonB mutant to that in chrysobactin-defective mutants. However, the pectinolytic activity, the major pathogenicity determinant in Er. chrysanthemi, appeared to be stimulated twofold in the tonB mutant.
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Affiliation(s)
- Corine Enard
- Laboratoire de Pathologie Végétale, UMR INRA/INA-PG, 16 rue Claude Bernard, 75231 Paris cedex 05, France1
| | - Dominique Expert
- Laboratoire de Pathologie Végétale, UMR INRA/INA-PG, 16 rue Claude Bernard, 75231 Paris cedex 05, France1
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Surgey N, Robert-Baudouy J, Condemine G. The Erwinia chrysanthemi pecT gene regulates pectinase gene expression. J Bacteriol 1996; 178:1593-9. [PMID: 8626286 PMCID: PMC177843 DOI: 10.1128/jb.178.6.1593-1599.1996] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A new type of Erwinia chrysanthemi mutant displaying a derepressed synthesis of pectate lyase was isolated. The gene mutated in these strains, pecT, encodes a 316-amino-acid protein with a size of 34,761 Da that belongs to the LysR family of transcriptional activators and presents 61% identity with the E. coli protein LrhA. PecT represses the expression of pectate lyase genes pelC, pelD, pelE, pelL, and kdgC, activates pelB, and has no effect on the expression of pelA or the pectin methylesterase genes pemA and pemB. PecT activiates its own expression. The mechanism by which PecT regulates pectate lyase synthesis is independent of that of the two characterized regulators of pectate lyase genes, KdgR and PecS. In contrast to most of the members of the LysR family, pecT is not transcribed in a direction opposite that of a gene that it regulates. pecT mutants are mucoid when grown on minimal medium plates and flocculate when grown in liquid minimal medium, unless leucine or alanine is added to the medium. Thus, pecT may regulate other functions in the bacterium.
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Affiliation(s)
- N Surgey
- Laboratoire de Génétique Moléculaire des Microorganismes, Unité Recherche Associée, Villeurbanne, France
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Gouesbet G, Trautwetter A, Bonnassie S, Wu LF, Blanco C. Characterization of the Erwinia chrysanthemi osmoprotectant transporter gene ousA. J Bacteriol 1996; 178:447-55. [PMID: 8550465 PMCID: PMC177677 DOI: 10.1128/jb.178.2.447-455.1996] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Growth of Erwinia chrysanthemi in media of elevated osmolarity can be achieved by the uptake and accumulation of various osmoprotectants. This study deals with the cloning and sequencing of the ousA gene-encoded osmoprotectant uptake system A from E. chrysanthemi 3937. OusA belongs to the superfamily of solute ion cotransporters. This osmotically inducible system allows the uptake of glycine betaine, proline, ectoine, and pipecolic acid and presents strong similarities in nucleotide sequence and protein function with the proline/betaine porter of Escherichia coli encoded by proP. The control of ousA expression is clearly different from that of proP. It is induced by osmotic strength and repressed by osmoprotectants. Its expression in E. coli is controlled by H-NS and is rpoS dependent in the exponential phase but unaffected by the stationary phase.
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Affiliation(s)
- G Gouesbet
- Centre National de la Recherche Scientifique (CNRS) URA 256, Département Membranes et Osmorégulation, Université de Rennes I, France
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van der Wolf JM, van Beckhoven JR, de Vries PM, Raaijmakers JM, Bakker PA, Bertheau Y, van Vuurde JW. Polymerase chain reaction for verification of fluorescent colonies of Erwinia chrysanthemi and Pseudomonas putida WCS358 in immunofluorescence colony staining. THE JOURNAL OF APPLIED BACTERIOLOGY 1995; 79:569-77. [PMID: 8567494 DOI: 10.1111/j.1365-2672.1995.tb03178.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The potential of polymerase chain reaction (PCR) for verifying the identity of colonies stained by the immunofluorescence colony-staining (IFC) procedure was investigated. Using primers directed against conserved sequences of the pectate lyase-genes coding for isozymes PLa, PLd and PLe of Erwinia chrysanthemi, the authors confirmed the identity of 96% of 20 fluorescent target colonies, punched from IFC-stained samples with pure cultures. In pour plates with mixtures of Erw. chrysanthemi and non-target colonies from potato peel extracts, the identity of 90% of 113 target colonies was confirmed. Using primers directed against sequences of the ferric-pseudobactin receptor gene pupA of Pseudomonas putida WCS358, the identity of 96% of 22 target colonies was confirmed in IFC-stained samples with pure cultures. In pour plates with mixtures of Ps. putida WCS358 and non-target bacteria from compost extracts, the identity of 59% of 108 fluorescent colonies was confirmed by PCR. It was shown that components from non-target bacteria lowered the threshold level of PCR for Ps. putida WCS358 100-fold.
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Affiliation(s)
- J M van der Wolf
- DLO Research Institute for Plant Protection (IPO-DLO), Wageningen, The Netherlands
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Moulard M, Condemine G, Nasser W, Robert-Baudouy J. Purification and characterization of the nuclease NucM of Erwinia chrysanthemi. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1262:133-8. [PMID: 7599187 DOI: 10.1016/0167-4781(95)00061-k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The major periplasmic nuclease of Erwinia chrysanthemi strain 3937, NucM, has been purified near to homogeneity by a one step purification procedure, using chromatography on a sulfopropyl column. NucM cleaves randomly single and double-stranded DNA and RNA. It does not need divalent cations for its action, and is more active in low salt buffers. A serine and a histidine residue could be present in the catalytic site. Formation of disulfide bonds is necessary for NucM activity. NucM is probably synthesized as a reduced inactive polypeptide and becomes active in the periplasm once disulfide bonds are formed.
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Affiliation(s)
- M Moulard
- Laboratoire de Génétique Moléculaire des Microorganismes et des Interactions Cellulaires, URA CNRS 1486, Institut National des Sciences Appliquées, Villeurbanne, France
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Lojkowska E, Masclaux C, Boccara M, Robert-Baudouy J, Hugouvieux-Cotte-Pattat N. Characterization of the pelL gene encoding a novel pectate lyase of Erwinia chrysanthemi 3937. Mol Microbiol 1995; 16:1183-95. [PMID: 8577252 DOI: 10.1111/j.1365-2958.1995.tb02341.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pelA, pelB, pelC, pelD and pelE genes. Recently, a new set of pectate lyases was identified in E. chrysanthemi mutants deleted of those pel genes. We cloned the pelL gene, encoding one of these secondary pectate lyases of E. chrysanthemi 3937, from a genomic bank of a strain deleted of the five major pel genes. The nucleotide sequence of the region containing the pelL gene was determined. The pelL reading frame is 1275 bases long, corresponding to a protein of 425 amino acids including a typical amino-terminal signal sequence of 25 amino acids. Comparison of the amino acid sequences of PelL and the exo-pectate lyase PelX of E. chrysanthemi EC16 revealed a low homology, limited to 220 residues of the central part of the proteins. No homology was detected with other bacterial pectinolytic enzymes. Regulation of pelL transcription was analysed using gene fusion. As shown for the other pel genes, the transcription of pelL is dependent on various environmental conditions. It is induced by pectic catabolic products and affected by growth phase, temperature, iron starvation, osmolarity, anaerobiosis, nitrogen starvation and catabolite repression. Regulation of pelL expression appeared to be independent of the KdgR repressor, which controls all the steps of pectin catabolism. In contrast, the pecS gene, which is involved in regulation of the synthesis of the major pectate lyases and of cellulase, also appeared to be involved in pelL expression. The PelL protein is able to macerate plant tissue. This enzyme has a basic isoelectric point, presents an endo-cleaving activity on polygalacturonate or partially methylated pectin, with a basic pH optimum and an absolute requirement for Ca2+. The pelL mutant displayed a reduced virulence on potato tubers and Saintpaulia ionantha plants, demonstrating the important role of this enzyme in soft-rot disease.
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Affiliation(s)
- E Lojkowska
- Department of Biotechnology, University of Gdansk, Poland
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Darrasse A, Priou S, Kotoujansky A, Bertheau Y. PCR and restriction fragment length polymorphism of a pel gene as a tool to identify Erwinia carotovora in relation to potato diseases. Appl Environ Microbiol 1994; 60:1437-43. [PMID: 7912502 PMCID: PMC201500 DOI: 10.1128/aem.60.5.1437-1443.1994] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Using a sequenced pectate lyase-encoding gene (pel gene), we developed a PCR test for Erwinia carotovora. A set of primers allowed the amplification of a 434-bp fragment in E. carotovora strains. Among the 89 E. carotovora strains tested, only the Erwinia carotovora subsp. betavasculorum strains were not detected. A restriction fragment length polymorphism (RFLP) study was undertaken on the amplified fragment with seven endonucleases. The Sau3AI digestion pattern specifically identified the Erwinia carotovora subsp. atroseptica strains, and the whole set of data identified the Erwinia carotovora subsp. wasabiae strains. However, Erwinia carotovora subsp. carotovora and Erwinia carotovora subsp. odorifera could not be separated. Phenetic and phylogenic analyses of RFLP results showed E. carotovora subsp. atroseptica as a homogeneous group while E. carotovora subsp. carotovora and E. carotovora subsp. odorifera strains exhibited a genetic diversity that may result from a nonmonophyletic origin. The use of RFLP on amplified fragments in epidemiology and for diagnosis is discussed.
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Affiliation(s)
- A Darrasse
- Institut National de la Recherche Agronomique INA P-G, Paris, France
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Hugouvieux-Cotte-Pattat N, Nasser W, Robert-Baudouy J. Molecular characterization of the Erwinia chrysanthemi kdgK gene involved in pectin degradation. J Bacteriol 1994; 176:2386-92. [PMID: 8157608 PMCID: PMC205363 DOI: 10.1128/jb.176.8.2386-2392.1994] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The pathways of pectin and galacturonate catabolism in Erwinia chrysanthemi converge to form a common intermediate, 2-keto-3-deoxygluconate (KDG), which is phosphorylated by KDG kinase encoded by the kdgK gene. We cloned the kdgK gene of E. chrysanthemi 3937 by complementing an Escherichia coli kdgK mutation, using an RP4-derivative plasmid. One of the kdgK R-prime plasmids harbored a DNA insert of about 80 kb and carried the uxuA and uxuB genes involved in glucuronate catabolism and the celY gene coding for an E. chrysanthemi cellulase. The kdgK and celY genes were precisely located on this plasmid, and their respective transcriptional directions were determined. The nucleotide sequence of the kdgK region indicated that the kdgK reading frame is 981 bases long, corresponding to a protein of 329 amino acids with a molecular mass of 36,377 Da. Analysis of the deduced primary amino acid sequence showed that this enzyme is a new member of the PfkB family of carbohydrate kinases. Expression of kdgK is controlled by a negative regulatory gene, kdgR, which represses all the steps of pectin degradation. Near the putative promoter of the kdgK gene, we identified a putative KdgR-binding site and demonstrated that the KdgR protein specifically binds in vitro to this DNA region. The KdgR-KDG couple directly mediates the phenomenon of repression or induction. The KDG kinase, by limiting the intracellular inducer concentration, appears to be a key enzyme in induction of the whole catabolic pathway.
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Affiliation(s)
- N Hugouvieux-Cotte-Pattat
- Laboratoire de Généteique Moléculaire des Microorganismes, CNRS URA-1486, INSA de Lyon, Villeurbanne, France
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Reverchon S, Nasser W, Robert-Baudouy J. pecS: a locus controlling pectinase, cellulase and blue pigment production in Erwinia chrysanthemi. Mol Microbiol 1994; 11:1127-39. [PMID: 8022282 DOI: 10.1111/j.1365-2958.1994.tb00389.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Erwinia chrysanthemi mutants (designated as pecS) displaying derepressed pectate lyase and cellulase synthesis were isolated. In addition, the pecS mutation is responsible for production of an extracellular insoluble blue pigment whose synthesis is cryptic in the wild-type 3937 strain. Transduction analysis indicates that the phenotype is due to a single mutation located near the xyl marker on the strain 3937 chromosome. This mutation was complemented by an R-prime plasmid carrying the xyl and argG genes of E. chrysanthemi, suggesting that the pecS product acts in trans to modulate pectinase, cellulase and blue pigment production. Insertion mutagenesis of the cloned region and recombination of the corresponding mutations in the bacterial chromosome by marker exchange revealed the existence of two divergently transcribed genes, pecS and pecM, that are both involved in the pectate lyase and cellulase regulation. The nucleotide sequences of pecS and pecM were determined. The pecS gene encodes a 166 amino acid polypeptide that shows similarity to the MprA regulatory protein of Escherichia coli whereas the pecM gene encodes a 297 amino acid polypeptide that was shown to be an integral membrane protein. The possible functions of the PecS and PecM proteins derived from the mutant phenotype and sequence analysis are discussed in terms of signal transduction and transcription regulation.
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Affiliation(s)
- S Reverchon
- Laboratoire de Génétique Moléculaire des Microorganismes, CNRS-URA 1486, INSA Bâtiment 406, Villeurbanne, France
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Hugouvieux-Cotte-Pattat N, Robert-Baudouy J. Molecular analysis of the Erwinia chrysanthemi region containing the kdgA and zwf genes. Mol Microbiol 1994; 11:67-75. [PMID: 8145647 DOI: 10.1111/j.1365-2958.1994.tb00290.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The pathways of pectin and galacturonate catabolism in Erwinia chrysanthemi converge to form a common intermediate, 2-keto-3-deoxygluconate, which is phosphorylated to form 2-keto-3-deoxy-6-phosphogluconate (KDGP) and then cleaved by the aldolase encoded by the kdgA gene. We cloned the kdgA gene of the E. chrysanthemi strain 3937 by complementing an Escherichia coli kdgA mutation, using an RP4-derivative plasmid. Restriction mapping of the kdgA region and isolation of kdgA-lac fusions allowed the more precise localization of the kdgA gene and determination of its transcriptional direction. The nucleotide sequence of the kdgA region indicated that the kdgA reading frame is 639 bases long, corresponding to a protein of 213 amino acids with a molecular mass of 22,187 Da. Comparison of the deduced primary amino acid sequences of the E. chrysanthemi KDGP-aldolase to the E. coli, Zymomonas mobilis and Pseudomonas putida enzymes showed that they are highly conserved. The E. chrysanthemi kdgA structural gene begins 153 bases downstream of an open reading frame that has a high homology with the zwf E. coli gene encoding glucose-6-phosphate dehydrogenase. The zwf gene is also linked to eda (kdgA) in E. coli and P. putida but genetic organization is different. Regulation of zwf and kdgA expression in E. chrysanthemi was analysed using lacZ fusions. The expression of zwf is independent of the growth rate, but is repressed in the presence of glucose. Induction of kdgA by pectin-degradation products is mediated in vivo by the negative regulatory gene kdgR, which also controls all the steps of pectin degradation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Douillié A, Toussaint A, Faelen M. Identification of the integration host factor genes of Erwinia chrysanthemi 3937. Biochimie 1994; 76:1055-62. [PMID: 7748927 DOI: 10.1016/0300-9084(94)90030-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Two Erwinia chrysanthemi homologues of the himA and himD genes of Escherichia coli which encode the integration host factor (IHF) were cloned, sequenced and compared to their homolog in other enterobacteria (EMBL accession nos X74749 and X74750). Both genes were inactivated by the insertion of an antibiotic resistance cassette, allowing for the isolation of IHF- mutants of E chrysanthemi.
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Affiliation(s)
- A Douillié
- Laboratoire de Génétique, Unité Transposition bactérienne, Université Libre de Bruxelles, Rhode-Saint-Genèse, Belgium
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42
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Darrasse A, Kotoujansky A, Bertheau Y. Isolation by genomic subtraction of DNA probes specific for Erwinia carotovora subsp. atroseptica. Appl Environ Microbiol 1994; 60:298-306. [PMID: 8117082 PMCID: PMC201303 DOI: 10.1128/aem.60.1.298-306.1994] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Erwinia carotovora subsp. atroseptica is a pathogen of potatoes in Europe because of its ability to induce blackleg symptoms early in the growing season. However, E. carotovora subsp. carotovora is not able to produce such severe symptoms under the same conditions. On the basis of the technique described by Straus and Ausubel (Proc. Natl. Acad. Sci. USA 87:1889-1893, 1990), we isolated DNA sequences of E. carotovora subsp. atroseptica 86.20 that were absent from the genomic DNA of E. carotovora subsp. carotovora CH26. Six DNA fragments ranging from ca. 180 to 400 bp were isolated, cloned, and sequenced. Each fragment was further hybridized with 130 microorganisms including 87 E. carotovora strains. One probe was specific for typical E. carotovora subsp. atroseptica strains, two probes hybridized with all E. carotovora subsp. atroseptica strains and with a few E. carotovora subsp. carotovora strains, and two probes recognized only a subset of E. carotovora subsp. atroseptica strains. The last probe was absent from the genomic DNA of E. carotovora subsp. carotovora CH26 but was present in the genomes of many strains, including those of other species and genera. This probe is homologous to the putP gene of Escherichia coli, which encodes a proline carrier. Further use of the probes is discussed.
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Affiliation(s)
- A Darrasse
- Institut National Agronomique Paris-Grignon, Institut National de la Recherche Agronomique, France
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43
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Laurent F, Kotoujansky A, Labesse G, Bertheau Y. Characterization and overexpression of the pem gene encoding pectin methylesterase of Erwinia chrysanthemi strain 3937. Gene X 1993; 131:17-25. [PMID: 8370537 DOI: 10.1016/0378-1119(93)90664-o] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The pem gene encoding the pectin methylesterase (PME) of Erwinia chrysanthemi strain 3937 was subcloned and its nucleotide sequence determined. The gene contains an open reading frame of 1098 bp and codes for a protein of 366 amino acids (aa). The mature 37-kDa form of the protein is 342 aa long and has a calculated isoelectric point of 9.64. A plasmid was constructed to overproduce PME: a DNA fragment carrying pem was amplified by the polymerase chain reaction and cloned downstream from the pL promoter of the lambda phage, in a high-copy-number plasmid. In an Escherichia coli strain transformed with this plasmid, an increase in PME production of more than 60-fold was obtained, compared with the wild-type Er. chrysanthemi strain. PME represents about 5% of the total protein content of the cells. Comparison of this PME sequence with six PMEs from prokaryotic or eukaryotic organisms showed six highly conserved segments whose possible role in enzyme activity are discussed.
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Affiliation(s)
- F Laurent
- INRA, INA-PG, Laboratoire de Pathologie Végétale, Paris, France
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Moulard M, Condemine G, Robert-Baudouy J. Characterization of the nucM gene coding for a nuclease of the phytopathogenic bacteria Erwinia chrysanthemi. Mol Microbiol 1993; 8:685-95. [PMID: 8332061 DOI: 10.1111/j.1365-2958.1993.tb01612.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The gene nucM encoding a nuclease was cloned from a genomic library of Erwinia chrysanthemi. The nucM gene was subcloned, and mutagenized by insertion of a uidA-KanR cartridge. This mutation was introduced by recombination into the Erwinia chrysanthemi chromosome. The nucM mutant lost NucM activity when tested on a DNA plate after 24 hours, but still possessed secondary weak nuclease activity. The nucleotide sequence of nucM was determined. It presents a 798 bp open reading frame, coding for a 266-amino-acid protein, with a predicted molecular mass of 29,910 Da. The deduced NucM protein shows 59% sequence identity with the DNase I precursor from Vibrio cholerae. It contains a typical leader sequence. Experiments of cell fractionation showed that NucM is periplasmic in E. chrysanthemi. The transcription start has been determined by S1 mapping. The -10 and -35 regions do not show homology with consensus sequence of the promoters recognized by sigma 70. In fact, the promoter seems to be dependent on the sigma 70, but the first transcription nucleotide is unusually far from the -10 region. nucM seems to be expressed constitutively.
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Affiliation(s)
- M Moulard
- Laboratoire de Génétique Moléculaire des Microorganismes, URA-CNRS 1486, Villeurbanne, France
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45
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Hugouvieux-Cotte-Pattat N, Dominguez H, Robert-Baudouy J. Environmental conditions affect transcription of the pectinase genes of Erwinia chrysanthemi 3937. J Bacteriol 1992; 174:7807-18. [PMID: 1447147 PMCID: PMC207497 DOI: 10.1128/jb.174.23.7807-7818.1992] [Citation(s) in RCA: 120] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
To depolymerize plant pectin, the phytopathogenic enterobacterium Erwinia chrysanthemi produces a series of enzymes which include a pectin-methyl-esterase encoded by the pem gene and five isoenzymes of pectate lyases encoded by the five genes pelA, pelB, pelC, pelD, and pelE. We have constructed transcriptional fusions between the pectinase gene promoters and the uidA gene, encoding beta-glucuronidase, to study the regulation of these E. chrysanthemi pectinase genes individually. The transcription of the pectinase genes is dependent on many environmental conditions. All the fusions were induced by pectic catabolic products and responded, to different degrees, to growth phase, catabolite repression, temperature, and nitrogen starvation. Transcription of pelA, pelD, and pelE was also increased in anaerobic growth conditions. High osmolarity of the culture medium increased expression of pelE but decreased that of pelD; the other pectinase genes were not affected. The level of expression of each gene was different. Transcription of pelA was very low under all growth conditions. The expression of the pelB, pelC, and pem genes was intermediate. The pelE gene had a high basal level of expression. Expression of pelD was generally the most affected by changes in culture conditions and showed a low basal level but very high induced levels. These differences in the expression of the pectinase genes of E. chrysanthemi 3937 presumably reflect their role during infection of plants, because the degradation of pectic polymers of the plant cell walls is the main determinant of tissue maceration caused by soft rot erwiniae.
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Affiliation(s)
- N Hugouvieux-Cotte-Pattat
- Laboratoire de Génétique Moléculaire des Microorganismes, URA-CNRS, Institut National des Sciences Appliquées batiment 406, Villeurbanne, France
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Hugouvieux-Cotte-Pattat N, Robert-Baudouy J. Analysis of the regulation of the pelBC genes in Erwinia chrysanthemi 3937. Mol Microbiol 1992; 6:2363-76. [PMID: 1406275 DOI: 10.1111/j.1365-2958.1992.tb01411.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Erwinia chrysanthemi secretes five major isoenzymes of pectate lyases encoded by the pelABCDE genes. The nucleotide sequence of the region surrounding the pelB gene of E. chrysanthemi 3937 was determined, including the regulatory regions involved in pelB and pelC expression. Analysis of the transcripts showed that transcription of pelB or pelC gave, in both cases, only one transcript. The transcription initiation sites of both pelB and pelC were precisely determined as well as the position of the transcription termination of pelB. The pelB and pelC promoters are very similar, showing a good homology with the -35 consensus region but low homology with the -10 consensus. In both cases a KdgR-box overlaps the -35 region. The pelC gene may have two KdgR operators. Moreover, the pelB and pelC genes are preceded by other sequences presenting the typical symmetry of operator sites that could be involved in more specific regulations. Comparison of E. chyrsanthemi pel regulatory regions revealed three classes of homology: pelA, pelB-pelC and pelD-pelE. The sole regulatory sequence conserved among the three classes corresponds to the KdgR-binding site. Moreover, all the pel regulatory regions are AT-rich in contrast to the coding regions which are GC-rich. Gel retardation experiments with fragments overlapping the pelB or pelC regulatory regions demonstrated that the KdgR protein specifically binds to these regions. Other proteins probably also interact with these DNA fragments. Transcription of pelB terminates in a region corresponding to a GC-rich inverted repeat followed by a run of T residues, typical of rho-independent transcription termination sites. Moreover, preliminary results imply that a region adjacent to pelC provoke, directly or indirectly, the repression of pelB and pelC expression.
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Affiliation(s)
- N Hugouvieux-Cotte-Pattat
- Laboratoire de Génétique Moléculaire des Microorganismes, CNRS, INSA, Bâtiment 406, Villeurbanne, France
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Expert D, Sauvage C, Neilands JB. Negative transcriptional control of iron transport in Erwinia chrysanthemi involves an iron-responsive two-factor system. Mol Microbiol 1992; 6:2009-17. [PMID: 1508046 DOI: 10.1111/j.1365-2958.1992.tb01373.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Systemic virulence of the phytopathogen Erwinia chrysanthemi 3937 requires a functional iron assimilation system which, in this enterobacterium, is mediated by the siderophore chrysobactin and the outer membrane transport protein Fct. We investigated the regulation of this system by iron. No direct similarity with the Escherichia coli fur gene was found. Insertional mutagenesis allowed isolation of a regulatory mutant which expressed chrysobactin and two other high-affinity iron transport systems previously characterized in strain 3937, regardless of the iron level. RNA/DNA hybridization analysis established that regulation of chrysobactin by iron occurs at the transcriptional level. From a wild-type gene library, a recombinant cosmid able to restore normal regulation in the mutant strain was isolated. By generating a series of subclones and mini-Mulac insertions, we identified a regulatory locus (cbr) extending beyond c. 2.5kb which encodes two polypeptides, CbrA and CbrB, with molecular weights of 34,000 and 55,000 respectively. Functional analysis of the locus suggests that the cognate genes cbrA and cbrB are clustered within an operon. Their expression was studied through chromosomal lac gene fusions, in the presence of plasmid-borne wild-type constructions, under high- and low-iron conditions. In summary, the data show that in the presence of iron, cbr negatively regulates the chrysobactin biosynthetic and transport genes, while under conditions of depletion, cbr is subject to negative autogeneous regulation.
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Affiliation(s)
- D Expert
- Laboratoire de Pathologie Végétale, Institut National de la Recherche Agronomique, Paris, France
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48
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Nasser W, Reverchon S, Robert-Baudouy J. Purification and functional characterization of the KdgR protein, a major repressor of pectinolysis genes of Erwinia chrysanthemi. Mol Microbiol 1992; 6:257-65. [PMID: 1545709 DOI: 10.1111/j.1365-2958.1992.tb02007.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The phytopathogenicity of the enterobacterium Erwinia chrysanthemi chiefly results from its capacity to degrade pectin, which is the major component of plant cell walls. This degradation requires the product of 12 genes which constitute independent transcriptional units. All these genes, including kdgT which encodes the 2-keto-3-deoxygluconate (KDG) transport system, are negatively regulated by the KdgR protein. The E. chrysanthemi kdgR gene was cloned into an expression vector and overexpressed in Escherichia coli. KdgR was then purified to homogeneity by two chromatographic steps as a dimer of approximately 62 kDa. Using gel retardation assays, we demonstrated that this purified repressor binds to the 25bp oligonucleotide (AAAAAAGAAACATTGTTTCATTTGT) present in the kdgT regulatory region. Dimethyl sulphate interference experiments revealed that the repressor interacts with four guanine bases and 10 adenine bases in the two strands of this KdgR box. KDG, an actual inducer of pectinolysis, releases the repressor from the operator complexes, whereas galacturonate, which is the precursor of the actual inducer, does not. These results suggest the existence of a specific interaction between KDG and KdgR protein. This study opens discussion on the relative affinity of the KdgR protein for the different operators of pectinolysis genes which are interpreted in terms of differential regulation.
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Affiliation(s)
- W Nasser
- Laboratoire de Génétique Moléculaire des Microorganismes, Institut National des Sciences Apliquées, Villeurbanne, France
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49
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Franza T, Expert D. The virulence-associated chrysobactin iron uptake system of Erwinia chrysanthemi 3937 involves an operon encoding transport and biosynthetic functions. J Bacteriol 1991; 173:6874-81. [PMID: 1657869 PMCID: PMC209040 DOI: 10.1128/jb.173.21.6874-6881.1991] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The iron assimilation system of Erwinia chrysanthemi 3937 is mediated by the catechol-type siderophore chrysobactin and the outer membrane transport protein Fct. We generated a variety of subclones in high- and low-copy-number vectors from a wild-type recombinant cosmid shown previously to carry the gene cluster fct-cbsA, cbsB, cbsC, cbsE encoding chrysobactin transport and biosynthetic functions, respectively. We studied their expression in Escherichia coli enterobactin-deficient entA, entB, entC, and entE mutants. This provided evidence that the fct and cbs genes are regrouped within a single genetic unit of ca. 8 kb in the following order: fct, cbsC, cbsE, cbsB, and cbsA. The gene boundaries were determined, and the various recombinant plasmids were expressed in Escherichia coli minicells: CbsA and CbsC enzymatic activities were clearly identified as polypeptides with apparent molecular masses of 32,000 and 38,000, respectively.
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Affiliation(s)
- T Franza
- Laboratoire de Pathologie Végétale, Institut National de la Recherche Agronomique, Paris, France
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50
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Reverchon S, Nasser W, Robert-Baudouy J. Characterization of kdgR, a gene of Erwinia chrysanthemi that regulates pectin degradation. Mol Microbiol 1991; 5:2203-16. [PMID: 1840643 DOI: 10.1111/j.1365-2958.1991.tb02150.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Erwinia chrysanthemi is a phytopathogenic enterobacterium able to degrade the pectic fraction of plant cell walls. The kdgR negative regulatory gene controls all the genes involved in pectin catabolism, including the pel genes encoding pectate lyases. The E. chrysanthemi kdgR regulatory gene was subcloned in Escherichia coli where it was shown to be functional, since it repressed the expression of a pelE::uidA fusion. The nucleotide sequence of kdgR contained an open reading frame of 918bp preceded by classical transcriptional initiation signals. KdgR shows similarity to two other regulatory proteins, namely GylR, encoding an activator protein of the glycerol operon in Streptomyces coelicolor, and IclR, encoding a repressor of the acetate operon in Salmonella typhimurium and in Escherichia coli. Previously, comparison of regulatory regions of several genes controlled by kdgR revealed the existence of a conserved region which was proposed as a KdgR-binding site. The 25 bp oligonucleotide AAAAAAGAAACATTGTTTCATTTGT corresponding to this consensus was substituted to the lac operator, at the beginning of transcription of the lacZ gene. This construct functioned as an operator for binding of the KdgR protein in vivo.
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Affiliation(s)
- S Reverchon
- Laboratoire de Génétique Moléculaire des Microorganismes, Institut National des Sciences Appliquées, Villeurbanne, France
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