Isolation and characterisation of transposon-induced mutants of Erwinia carotovora subsp. atroseptica exhibiting reduced virulence

  title={Isolation and characterisation of transposon-induced mutants of Erwinia carotovora subsp. atroseptica exhibiting reduced virulence},
  author={Jay C. D. Hinton and Julie M. Sidebotham and L. J. Hyman and Michel C. M. P{\'e}rombelon and George P. C. Salmond},
  journal={Molecular and General Genetics MGG},
SummaryThe blackleg pathogen Erwinia carotovora subsp. atroseptica (Eca) causes an economically important disease of potatoes. We selected a genetically amenable Eca strain for the genetic analysis of virulence. Tn5 mutagenesis was used to generate nine mutants which exhibited reduced virulence (Rvi-) of strain SCRI1043. Following physiological characterisation, mutants were divided into three classes: (1) auxotrophs; (2) extracellular enzyme mutants; and (3) a growth rate mutant. The isolation… 
Two mobile Pectobacterium atrosepticum prophages modulate virulence.
Deletion of the entire prophages, both separately and in combination, did not affect the growth rate or the secretion of plant cell wall-degrading enzymes, but swimming motility was decreased and the virulence of prophage deletion strains in the potato host was decreased.
Exploitation of a new flagellatropic phage of Erwinia for positive selection of bacterial mutants attenuated in plant virulence: towards phage therapy
Aims:  To isolate and characterize novel bacteriophages for the phytopathogen, Erwinia carotovora ssp. atroseptica (Eca), and to isolate phage‐resistant mutants attenuated in virulence.
Bacterial diseases of potatoes: from classical phytobacteriology to molecular pathogenicity
  • G. Salmond
  • Biology
    Netherlands Journal of Plant Pathology
  • 2005
Advances in the molecular biological analysis of several bacterial pathogens are helping to understand the major aspects of virulence mechanisms, but to date such information is not sufficiently useful to allow us to intervene rationally in these potato diseases, except by the standard practises of good husbandry.
Genome wide identification of genes required for bacterial plant infection by Tn-seq
Tn-seq is used for the first time in a plant pathogenic bacteria to identify genes required for the multiplication of Dickeya dadantii in chicory and it is shown that D.Dadantii flagellin is glycosylated and that this modification confers fitness to the bacteria during plant infection.
Expression of pehA-bla gene fusions in Erwinia carotovora subsp. carotovora and isolation of regulatory mutants affecting polygalacturonase production
The PehR−1 as well as PehA−1 mutants exhibited a reduced virulence phenotype suggesting that polygalacturonase is a virulence factor in Ecc, and two classes of regulatory mutants were obtained by this selection.
Identification of the central quorum sensing regulator of virulence in the enteric phytopathogen, Erwinia carotovora: the VirR repressor
It is demonstrated that the VirR regulatory pathway is present and functional in both blackleg and soft rotting species of Erwinia, and evidence that VirR acts to prevent the production of virulence factors at low cell density is provided.
Identification by Tn‐seq of Dickeya dadantii genes required for survival in chicory plants
This study demonstrated that the biosynthetic pathways of leucine, cysteine and lysine were essential for bacterial survival in the plant and that RsmC and GCPA were important in the regulation of the infection process, as the mutants ∆rsmC and ∆gcpA were hypervirulent.
RelA-Dependent (p)ppGpp Production Controls Exoenzyme Synthesis in Erwinia carotovora subsp. atroseptica
It is concluded that nutrient limitation is a potent environmental cue that triggers (p)ppGpp-dependent exoenzyme production in E. carotovora subsp.
Use of a pooled transposon mutation grid to demonstrate roles in disease development for Erwinia carotovora subsp. atroseptica putative type III secreted effector (DspE/A) and helper (HrpN) proteins.
An arrayed set of Tn5 insertional mutants was constructed and pooled to allow rapid isolation of mutants for any given gene by polymerase chain reaction screening, and this novel approach was used to obtain mutations in two structural genes (hrcC and hrcV) and the effector gene dspE/A, and the helper gene hrpN.
A metabolic regulator modulates virulence and quorum sensing signal production in Pectobacterium atrosepticum.
The metJ mutant strains showed pleiotropic transcriptional impacts affecting approximately a quarter of the genome and genes involved in methionine biosynthesis were most highly upregulated but many virulence-associated transcripts were also upregulated.


Isolation and Characterization of Pectolytic Nonpathogenic Mutants of Erwinia Carotovora Subsp. Carotovora ( Ecc )
Results indicate that several gene products including those which regulate the synthesis and secretion of pectolytic enzymes are involved in pathogenicity of E. carotovora.
Bacteriocin-resistant mutants of Erwinia chrysanthemi: possible involvement of iron acquisition in phytopathogenicity
A series of bacteriocin-resistant mutants of Erwinia chrysanthemi 3937JRH were unable to elicit soft-rot symptoms on saintpaulia plants and did not exhibit altered extracellular pectinolytic or cellulolytic activities.
Cloning of a Gene from Erwinia Amylovora Involved in Induction of Hypersensitivity and Pathogenicity
Most phytopathogenic bacteria that cause necrotic type symptoms, including Erwinia amylovora, induce a hypersensitive reaction (HR) when high bacterial numbers are introduced into nonhost plant
Cloning of the cysB gene of Erwinia carotovora subsp. carotovora, and the identification of its product
SummaryThe suicide vector pJB4JI was used to generate a range of Tn5-induced mutants of Erwinia carotovora subsp. carotovora (Ecc). One mutant, HC500, was a cysteine auxotroph which had a
Use of TnphoA to enrich for extracellular enzyme mutants of Erwinia carotovora subspecies carotovora
The use of TnphoA provides an enrichment for extracellular enzyme mutants over other transposon‐based systems and is a useful model for the study of protein secretion by Gram‐negative bacteria.
Transposon Mutagenesis of Pseudomonas solanacearum: Isolation of Tn5-Induced Avirulent Mutants
Transposon mutagenesis in a tomato isolate of Pseudomonas solanacearum (strain Kourou) is reported, using Tn7 and Tn5 inserted in suicide conjugative plasmids, allowing isolation of auxotrophic mutants with a frequency of 035%.
Characterization and virulence properties of Erwinia chrysanthemi lipopolysaccharide-defective, phi EC2-resistant mutants
Two phi EC2r mutants (RH6053 and RH6065) were most severely affected in their outer membrane integrity and also lost their virulence on saintpaulia plants, although they still possessed normal extracellular levels of pectinolytic and cellulolytic activities.
Transposon mutagenesis of Erwinia using phage λ vectors
The plasmid pHCP2 carries the lamB gene of E. coli and was transferred to 4 strains of Erwinia using transformation or conjugal mobilisation, which resulted in mutant phenotypes that were sensitive to λ infection.
Isolation of Avirulent Mutants of Erwinia stewartii Using Bacteriophage Mu pf7701
Bacteriophage Mu pf7701, a KmR derivative of Mu cts62, was inserted into the conjugative Erwinia stewartii plasmid pDC251, which carries Tn10, and the largest colonies arose from transconjugants in which Mu p f7701 had transposed to the chromosome and the pDC 251 plasmids had been lost.
Identification of a new virulence locus in Agrobacterium tumefaciens that affects polysaccharide composition and plant cell attachment
A new virulence locus in Agrobacterium tumefaciens is identified, and DNA hybridization analysis and genetic complementation experiments indicated that the pscA locus is not encoded by the Ti plasmid and that it is distinct from the previously described chromosomal virulent loci chvA and chvB.