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Klaus Geider - One of the best experts on this subject based on the ideXlab platform.
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6-thioguanine biosynthesis in Erwinia species
Acta Horticulturae, 2014Co-Authors: Annette Wensing, Klaus Geider, M. Gernold, Susanne Jock, Wilhelm Jelkmann, Alfred Beck, R. JansenAbstract:Erwinia amylovora produces a compound with an absorbance maximum at 340 nm that forms a yellow colored complex with copper. This compound was identified as 6-thioguanine, a guanine analogue that is used in chemotherapy and the treatment of inflammatory bowel disease. Synthesis of 6-thioguanine could be linked to five genes common in Erwinia genomes, but missing in related genera. Expression of Erwinia tasmaniensis genes tgsA-D in Escherichia coli was sufficient for heterologous production of 6-thioguanine. Transfer of the four biosynthetic E. tasmaniensis genes did not enhance resistance of E. coli against 6-thioguanine. Bacterial and synthetic 6-thioguanine have a strong growth inhibitory effect on many bacteria, such as E. coli or a number of Pantoea agglomerans isolates. While this inhibition of competing species might provide an advantage to Erwinia, further biological functions of 6-thioguanine cannot be excluded. A direct link between 6-thioguanine synthesis of E. amylovora and its pathogenicity was not observed, as two 6-thioguanine negative mutants produced as severe symptoms on apple and pear shoots as did producing strains.
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Expression of Lysozymes from Erwinia amylovora Phages and Erwinia Genomes and Inhibition by a Bacterial Protein
Journal of molecular microbiology and biotechnology, 2012Co-Authors: Ina Müller, M. Gernold, Bernd Schneider, Klaus GeiderAbstract:Genes coding for lysozyme-inhibiting proteins (Ivy) were cloned from the chromosomes of the plant pathogens Erwinia amylovora and Erwinia pyrifoliae. The product interfered not only with activity of hen egg white lysozyme, but also with an enzyme from E. amylovora phage ΦEa1h. We have expressed lysozyme genes from the genomes of three Erwinia species in Escherichia coli. The lysozymes expressed from genes of the E. amylovora phages ΦEa104 and ΦEa116, Erwinia chromosomes and Arabidopsis thaliana were not affected by Ivy. The enzyme from bacteriophage ΦEa1h was fused at the N- or C-terminus to other peptides. Compared to the intact lysozyme, a His-tag reduced its lytic activity about 10-fold and larger fusion proteins abolished activity completely. Specific protease cleavage restored lysozyme activity of a GST-fusion. The bacteriophage-encoded lysozymes were more active than the enzymes from bacterial chromosomes. Viral lyz genes were inserted into a broad-host range vector, and transfer to E. amylovora inhibited cell growth. Inserted in the yeast Pichia pastoris, the ΦEa1h-lysozyme was secreted and also inhibited by Ivy. Here we describe expression of unrelated cloned ‘silent’ lyz genes from Erwinia chromosomes and a novel interference of bacterial Ivy proteins with a viral lysozyme.
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Hypersensitive response and acyl-homoserine lactone production of the fire blight antagonists Erwinia tasmaniensis and Erwinia billingiae.
Microbial biotechnology, 2008Co-Authors: Vladimir Jakovljevic, Susanne Jock, Klaus GeiderAbstract:Fire blight caused by the Gram‐negative bacterium Erwinia amylovora can be controlled by antagonistic microorganisms. We characterized epiphytic bacteria isolated from healthy apple and pear trees in Australia, named Erwinia tasmaniensis, and the epiphytic bacterium Erwinia billingiae from England for physiological properties, interaction with plants and interference with growth of E. amylovora. They reduced symptom formation by the fire blight pathogen on immature pears and the colonization of apple flowers. In contrast to E. billingiae, E. tasmaniensis strains induced a hypersensitive response in tobacco leaves and synthesized levan in the presence of sucrose. With consensus primers deduced from lsc as well as hrpL, hrcC and hrcR of the hrp region of E. amylovora and of related bacteria, these genes were successfully amplified from E. tasmaniensis DNA and alignment of the encoded proteins to other Erwinia species supported a role for environmental fitness of the epiphytic bacterium. Unlike E. tasmaniensis, the epiphytic bacterium E. billingiae produced an acyl‐homoserine lactone for bacterial cell‐to‐cell communication. Their competition with the growth of E. amylovora may be involved in controlling fire blight.
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Autoinducer-2 of the fire blight pathogen Erwinia amylovora and other plant-associated bacteria
Fems Microbiology Letters, 2006Co-Authors: Mojtaba Mohammadi, Klaus GeiderAbstract:Autoinducers are important for cellular communication of bacteria. The luxS gene has a central role in the synthesis of autoinducer-2 (AI-2). The gene was identified in a shotgun library of Erwinia amylovora and primers designed for PCR amplification from bacterial DNA. Supernatants of several Erwinia amylovora strains were assayed for AI-2 activity with a Vibrio harveyi mutant and were positive. Many other plant-associated bacteria also showed AI-2 activity such as Erwinia pyrifoliae and Erwinia tasmaniensis. The luxS genes of several bacteria were cloned, sequenced, and complemented Escherichia coli strain DH5α and a Salmonella typhimurium mutant, both defective in luxS, for synthesis of AI-2. Assays to detect AI-2 activity in culture supernatants of several Pseudomonas syringae pathovars failed, which may indicate the absence of AI-2 or synthesis of another type. Several reporter strains did not detect synthesis of an acyl homoserine lactone (AHL, AI-1) by Erwinia amylovora, but confirmed AHL-synthesis for Erwinia carotovora ssp. atroseptica and Pantoea stewartii.
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Molecular comparison of pathogenic bacteria from pear trees in Japan and the fire blight pathogen Erwinia amylovora.
Microbiology (Reading England), 2001Co-Authors: W S Kim, M Hildebrand, S Jock, Klaus GeiderAbstract:Several strains of the genus Erwinia, which were isolated in Japan from pear trees with necrotic symptoms that resembled fire blight, and tentatively identified as Erwinia amylovora, were reinvestigated for their relationship to the fire blight pathogen. These isolates produced ooze on slices of immature pears and were mucoid on MM2Cu agar plates, but did not synthesize levan and did not give the expected PCR signals with several primer pairs specific for Erwinia amylovora. The isolates tested positive with PCR primers designed to detect the novel pear pathogen Erwinia pyrifoliae, which was isolated from Nashi pear trees in South Korea. The nucleotide sequence analysis of a DNA fragment preceding the gene cluster for exopolysaccharide synthesis revealed a closer relationship to Erwinia pyrifoliae than to Erwinia amylovora. Plasmid profiles, protein patterns and genomic DNA analysed by PFGE after XbaI and SpeI digestion were different than Erwinia amylovora. Experiments with strains of Erwinia amylovora isolated from raspberry (Rubus sp.), Erwinia mallotivora and Enterobacter pyrinus also did not reveal a relationship between these bacteria and the Japanese Erwinia strains. The latter are not identical to Erwinia pyrifoliae, but possess many similar features to this pathogen that causes Asian pear blight. It is concluded that pathogenic bacteria isolated in Japan from pear trees with symptoms resembling fire blight are possibly different from Erwinia amylovora.
Ian K. Toth - One of the best experts on this subject based on the ideXlab platform.
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Application of Amplified Fragment Length Polymorphism Fingerprinting for Taxonomy and Identification of the Soft Rot Bacteria Erwinia carotovora and Erwinia chrysanthemi
Applied and environmental microbiology, 2002Co-Authors: Anna O. Avrova, L. J. Hyman, Rachel L. Toth, Ian K. TothAbstract:The soft rot bacteria Erwinia carotovora and Erwinia chrysanthemi are important pathogens of potato and other crops. However, the taxonomy of these pathogens, particularly at subspecies level, is unclear. An investigation using amplified fragment length polymorphism (AFLP) fingerprinting was undertaken to determine the taxonomic relationships within this group based on their genetic relatedness. Following cluster analysis on the similarity matrices derived from the AFLP gels, four clusters (clusters 1 to 4) resulted. Cluster 1 contained Erwinia carotovora subsp. carotovora (subclusters 1a and 1b) and Erwinia carotovora subsp. odorifera (subcluster 1c) strains, while cluster 2 contained Erwinia carotovora subsp. atroseptica (subcluster 2a) and Erwinia carotovora subsp. betavasculorum (subcluster 2b) strains. Clusters 3 and 4 contained Erwinia carotovora subsp. wasabiae and E. chrysanthemi strains, respectively. While E. carotovora subsp. carotovora and E. chrysanthemi showed a high level of molecular diversity (23 to 38% mean similarity), E. carotovora subsp. odorifera, E. carotovora subsp. betavasculorum, E. carotovora subsp. atroseptica, and E. carotovora subsp. wasabiae showed considerably less (56 to 76% mean similarity), which may reflect their limited geographical distributions and/or host ranges. The species- and subspecies-specific banding profiles generated from the AFLPs allowed rapid identification of unknown isolates and the potential for future development of diagnostics. AFLP fingerprinting was also found to be more differentiating than other techniques for typing the soft rot Erwinias and was applicable to all strain types, including different serogroups.
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The isolation of novel Erwinia phages and their use in the study of bacterial phytopathogenicity
1991Co-Authors: Ian K. TothAbstract:A number of bacteriophages were isolated on the "soft rot" phytopathogens Erwinia carotovora subsp. atroseptica SCRI1043 and Erwinia carotovora subsp. carotovora SCRI193. Several of these phages were used to obtain phage resistant mutants of SCRI1043, in order to investigate the role of the bacterial cell surface in virulence. While a number of phenotypic properties relating to pathogenicity and virulence of this strain have already been uncovered, little is known about the role of the cell surface in virulence. It was hoped that the use of phages would allow selection of mutants altered in both cell surface and virulence. Two phage resistant mutants, A5/22 and A5/8, exhibited reduced virulence when inoculated into potato plants, and were investigated further. Both mutants showed pleiotropic phenotypes. As well as reduced virulence and phage resistance, these mutants showed a number of other phenotypic alterations including, a reduction in the production of plant cell wall degrading enzymes, increased sensitivity to surface active agents, alterations in lipopolysaccharide and outer membrane protein profiles and reduced motility. A5/22 also exhibited bacteriostasis in the presence of galactose. Mutant A5/22 was more severely affected in its virulence than A5/8, which reflected in its greater deviation from the wild type phenotype. While no one phenotypic alteration could be directly associated with the reduced virulence of either mutant, a combination of several phenotypes may have been responsible. The phages isolated in this study were the first reported for these strains of Erwinia, and were therefore characterised under a number of criteria. All phages were grouped on the basis of structural morphology, restriction endonuclease digestion and host range. This is the first detailed characterisation of phages for Erwinia carotovora subsp. atroseptica. All isolated phages were tested for generalised transduction, a method of molecular genetic analysis so far unavailable to Erwinia carotovora subsp. atroseptica SCRI1043 and Erwinia carotovora subsp. carotovora SCRI193. Two phages, OKP and OMl, were capable of generalised transduction in SCRI193 and SCRI1043 respectively. Both these phages were characterised and transducing frequencies improved. OMl is the first transducing phage reported for Erwinia carotovora subsp. atroseptica and OKP is only the second for Erwinia carotovora subsp. carotovora. Both phages are now being used extensively in the laboratory.
Louis Gardan - One of the best experts on this subject based on the ideXlab platform.
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Erwinia piriflorinigrans sp. nov., a novel pathogen that causes necrosis of pear blossoms.
International Journal of Systematic and Evolutionary Microbiology, 2010Co-Authors: María M. López, M. Roselló, Pablo Llop, Sergi Ferrer, Richard Christen, Louis GardanAbstract:Eight Erwinia strains isolated from necrotic pear blossoms in Valencia, Spain, were compared to reference strains of Erwinia amylovora and Erwinia pyrifoliae, both pathogenic in pear species, and to other species of Enterobacteriaceae by a polyphasic approach. Phenotypic analyses clustered them into one phenon, different from those of other Erwinia spp. and showed that such isolates constituted a homogeneous phenotypic group. Their rep-PCR profile, the PCR products obtained with different pairs of primers and their plasmid content followed by restriction analysis showed differences when compared to those of Erwinia amylovora and Erwinia pyrifoliae reference strains. Phylogenetic analysis of 16S rRNA gene, gpd and recA sequences showed that they could not be assigned undoubtedly to any single known species, because of the high similarity values. The isolates from necrotic pear blossoms constituted a single DNA hybridization group which was 87 to 100 % related to the strain CFBP 5888T and other Erwinia species were 22.7 to 50 % related to the type strain of the novel pathogen. The G+C content of two strains was 51.1 and 50.5 mol%. On the basis of these and previous results, the isolates from necrotic pear blossoms are proposed as members of a new species for which the name Erwinia piriflorinigrans is suggested. The type strain is strain CFBP 5888T (CECT 7348T).
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The phytopathogenic bacteria Erwinia carotovora infects Drosophila and activates an immune response
Proceedings of the National Academy of Sciences of the United States of America, 2000Co-Authors: Alan Basset, Louis Gardan, Ranjiv S. Khush, Anne Braun, Frédéric Boccard, Jules A. Hoffmann, Bruno LemaitreAbstract:Although Drosophila possesses potent immune responses, little is known about the microbial pathogens that infect Drosophila. We have identified members of the bacterial genus Erwinia that induce the systemic expression of genes encoding antimicrobial peptides in Drosophila larvae after ingestion. These Erwinia strains are phytopathogens and use flies as vectors; our data suggest that these strains have also evolved mechanisms for exploiting their insect vectors as hosts. Erwinia infections induce an antimicrobial response in Drosophila larvae with a preferential expression of antibacterial versus antifungal peptide-encoding genes. Antibacterial peptide gene expression after Erwinia infection is reduced in two Drosophila mutants that have reduced numbers of hemocytes, suggesting that blood cells play a role in regulating Drosophila antimicrobial responses and also illustrating that this Drosophila–Erwinia interaction provides a powerful model for dissecting host–pathogen relationships.
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Erwinia pyrifoliae sp nov a novel pathogen that affects asian pear trees pyrus pyrifolia nakai
International Journal of Systematic and Evolutionary Microbiology, 1999Co-Authors: Wonsik Kim, Louis Gardan, S L Rhim, Klaus GeiderAbstract:A novel pathogen from Asian pears (Pyrus pyrifolia Nakai) was analysed by sequencing the 16S rDNA and the adjacent intergenic region, and the data were compared to related Enterobacteriaceae. The 16S rDNA of the Asian pear pathogen was almost identical with the sequence of Erwinia amylovora, in contrast to the 16S-23S rRNA intergenic transcribed spacer region of both species. A dendrogram was deduced from determined sequences of the spacer regions including those of several related species such as Erwinia amylovora, Enterobacter pyrinus, Pantoea stewartii subsp. stewartii and Escherichia coli. Dendrograms derived from 121 biochemical characteristics including Biotype 100 data placed the Asian pear pathogen close to Erwinia amylovora and more distantly to other members of the species Erwinia and to the species Pantoea and Enterobacter. Another DNA relatedness study was performed by DNA hybridizations and estimation of delta Tm values. The Asian pear strains constituted a tight DNA hybridization group (89-100%) and were barely related to strains of Erwinia amylovora (40-50%) with a delta Tm in the range of 5.2-6.8. The G + C content of DNA from the novel pathogen is 52 mol%. Therefore, it is proposed that strains isolated from Asian pears constitute a new species and the name Erwinia pyrifoliae is suggested; the type strain is strain Ep 16/96T (= CFBP 4172T = DSM 12163T).
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Description of a new disease on Erythrina sp. in Martinique (French West Indies) and preliminary characterization of the causal agent as a novel Erwinia species
Plant Pathology, 1999Co-Authors: Lydie Sutra, Philippe Prior, K. Perlemoine, J.m. Risède, P. Cao-van, Louis GardanAbstract:In spring 1995, symptoms of partial defoliation were observed an Erythrina indica var. fastigiata trees, commonly used as windbreaks in banana plantations in Martinique (French West Indies). Browning of the bark surface was consistently observed at the base of defoliated branches. Bacteria were isolated as nearly pure cultures from typical necrotic lesions an the bark. Results of Gram stain, staining of flagella and biochemical tests indicated that all isolates belonged to the Enterobacteriaceae, and to the genus Erwinia. Numerical analysis of the results of 48 biochemical properties showed that Erwinia isolates from diseased erythrina trees constituted a homogenous phenotypic cluster, and that, although weakly pectolytic, these isolates were closely related to pectolytic Erwinia species: E. carotovora ssp. betavasculorum and ssp. wasabiae, and E, cacticida. However, they could be clearly distinguished by different biochemical characteristics from type strains of known plant pathogenic species of Erwinia, Pantoea and Enterobacter. Under greenhouse conditions, the isolates were pathogenic to Erythrina indica var. fastigiata cuttings, but not to banana and pineapple, which are major crops in Martinique.
J Robert-baudouy - One of the best experts on this subject based on the ideXlab platform.
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Molecular biology of Erwinia: from soft-rot to antileukaemics
Trends in Biotechnology, 1991Co-Authors: J Robert-baudouyAbstract:Abstract Soft-rot Erwinia has served to model the regulatory mechanisms in plant-pathogen interactions, and studies have revealed the extracellular pectinolytic, cellulolytic and proteolytic enzymes to be major virulence factors in Erwinia pathogenesis. Apart from its agricultural significance, Erwinia is of increasing interest as an industrial microbe: the Erwinia secretory apparatus, when cloned in Escherichia coli , enables this organism to secrete heterologous Erwinia pectinases, and molecular studies in Erwinia have facilitated the industrial production of pectin methylesterase (important in fruit-juice processing), vitamin C and the antileukaemic asparaginase.
Anna O. Avrova - One of the best experts on this subject based on the ideXlab platform.
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Application of Amplified Fragment Length Polymorphism Fingerprinting for Taxonomy and Identification of the Soft Rot Bacteria Erwinia carotovora and Erwinia chrysanthemi
Applied and environmental microbiology, 2002Co-Authors: Anna O. Avrova, L. J. Hyman, Rachel L. Toth, Ian K. TothAbstract:The soft rot bacteria Erwinia carotovora and Erwinia chrysanthemi are important pathogens of potato and other crops. However, the taxonomy of these pathogens, particularly at subspecies level, is unclear. An investigation using amplified fragment length polymorphism (AFLP) fingerprinting was undertaken to determine the taxonomic relationships within this group based on their genetic relatedness. Following cluster analysis on the similarity matrices derived from the AFLP gels, four clusters (clusters 1 to 4) resulted. Cluster 1 contained Erwinia carotovora subsp. carotovora (subclusters 1a and 1b) and Erwinia carotovora subsp. odorifera (subcluster 1c) strains, while cluster 2 contained Erwinia carotovora subsp. atroseptica (subcluster 2a) and Erwinia carotovora subsp. betavasculorum (subcluster 2b) strains. Clusters 3 and 4 contained Erwinia carotovora subsp. wasabiae and E. chrysanthemi strains, respectively. While E. carotovora subsp. carotovora and E. chrysanthemi showed a high level of molecular diversity (23 to 38% mean similarity), E. carotovora subsp. odorifera, E. carotovora subsp. betavasculorum, E. carotovora subsp. atroseptica, and E. carotovora subsp. wasabiae showed considerably less (56 to 76% mean similarity), which may reflect their limited geographical distributions and/or host ranges. The species- and subspecies-specific banding profiles generated from the AFLPs allowed rapid identification of unknown isolates and the potential for future development of diagnostics. AFLP fingerprinting was also found to be more differentiating than other techniques for typing the soft rot Erwinias and was applicable to all strain types, including different serogroups.