| is1327, a new insertion-like element in the pathogenicity-associated plasmid of erwinia herbicola pv. gypsophilae. | the pathogenicity-associated plasmid (ppath) of erwinia herbicola pv. gypsophilae was previously shown to be exclusively present in pathogenic strains and to contain a gene cluster encoding phytohormone biosynthesis. sequence analysis of the dna region located downstream from the cytokinin biosynthetic gene (etz) revealed homology to insertion sequences (is) of the is6 family. southern blot analysis performed on plasmid dna of e. herbicola pv. gypsophilae revealed the presence of six copies of t ... | 1996 | 8820751 |
| molecular characterization of global regulatory rna species that control pathogenicity factors in erwinia amylovora and erwinia herbicola pv. gypsophilae. | rsmb(ecc) specifies a nontranslatable rna regulator that controls exoprotein production and pathogenicity in soft rot-causing erwinia carotovora subsp. carotovora. this effect of rsmb(ecc) rna is mediated mostly by neutralizing the function of rsma(ecc), an rna-binding protein of e. carotovora subsp. carotovora, which acts as a global negative regulator. to determine the occurrence of functional homologs of rsmb(ecc) in non-soft-rot-causing erwinia species, we cloned the rsmb genes of e. amylovo ... | 2001 | 11222584 |
| a host-specific virulence protein of erwinia herbicola pv. gypsophilae is translocated into human epithelial cells by the type iii secretion system of enteropathogenic escherichia coli. | summary hsvg is a virulence factor that determines the host specificity of erwinia herbicola pathovars gypsophilae and betae on gypsophila. we used the calmodulin adenylate cyclase reporter (cyaa) to demonstrate that hsvg is secreted and translocated into hela cells by the type iii secretion system (ttss) of the enteropathogenic escherichia coli (epec). a fusion of hsvg-cyaa containing 271 amino acids of the n-terminus of hsvg were introduced into a wild-type epec, espb mutant deficient in trans ... | 2002 | 20569314 |
| regulatory interactions between quorum-sensing, auxin, cytokinin, and the hrp regulon in relation to gall formation and epiphytic fitness of pantoea agglomerans pv. gypsophilae. | gall formation by pantoea agglomerans pv. gypsophilae is controlled by hrp/hrc genes, phytohormones, and the quorum-sensing (qs) regulatory system. the interactions between these three components were investigated. disruption of the qs genes pagi and pagr and deletion of both substantially reduced the transcription levels of the hrp regulatory genes hrpxy, hrps, and hrpl, as determined by quantitative reverse-transcriptase polymerase chain reaction. expression of hrpl in planta was inhibited by ... | 2009 | 19522567 |
| quorum-sensing system affects gall development incited by pantoea agglomerans pv. gypsophilae. | the quorum-sensing (qs) regulatory system of the gall-forming pantoea agglomerans pv. gypsophilae was identified. mass spectral analysis, together with signal-specific biosensors, demonstrated that p. agglomerans pv. gypsophilae produced n-butanoyl-l-homoserine lactone (c4-hsl) as a major and n-hexanoyl-l-homoserine lactone (c6-hsl) as a minor qs signal. homologs of luxi and luxr regulatory genes, pagi and pagr, were characterized in strain p. agglomerans pv. gypsophilae pag824-1 and shown to be ... | 2008 | 18616406 |
| the type iii effectors hsvg and hsvb of gall-forming pantoea agglomerans determine host specificity and function as transcriptional activators. | pantoea agglomerans pv. gypsophilae (pag) elicits galls on gypsophila and a hypersensitive response on beet, whereas p. agglomerans pv. betae (pab) induces galls on both beet and gypsophila. the pathogenicity of both pathovars is dependent on the presence of a plasmid harbouring type iii secretion system (ttss) components and effectors. the hsvg ttss effectors of pag (hsvg-pag) and pab (hsvg-pab) determine the host specificity of both pathovars on gypsophila. here we describe a novel hsvg homolo ... | 2006 | 16879413 |
| comparative anatomy of gall development on gypsophila paniculata induced by bacteria with different mechanisms of pathogenicity. | galls induced on gypsophila paniculata by pantoea agglomerans pv. gypsophilae (pag) and agrobacterium tumefaciens (at), bacteria with different mechanisms of pathogenicity, were compared morphologically and anatomically. the pathogenicity of pag is dependent on the presence of an indigenous plasmid that harbors hrp gene cluster, genes encoding hop virulence proteins and biosynthetic genes for auxin (iaa) and cytokinins (cks), whereas that of at involves host transformation. the pag-induced gall ... | 2006 | 16477460 |
| analysis of promoters recognized by hrpl, an alternative sigma-factor protein from pantoea agglomerans pv. gypsophilae. | hrpl, an alternative sigma factor, activates the transcription of the hrp regulon by its binding to a common "hrp box" promoter. based on computational techniques, the hrp box previously was defined as a consensus bipartite cis element, 5'-ggaacc-n(15-16)-ccacnna-3'. the present report combines a quantitative in vivo assay for measuring hrp promoter activity with site-specific mutagenesis to analyze the effect of consensus and nonconsensus nucleotides on promoter activity. the analysis was carri ... | 2005 | 16042009 |
| the regulatory cascade that activates the hrp regulon in erwinia herbicola pv. gypsophilae. | the pathogenicity of erwinia herbicola pv. gypsophilae (ehg) is dependent on a plasmid (ppath(ehg)) that harbors the hrp gene cluster and additional virulence genes. the hrp regulatory cascade of ehg comprises an hrpxy operon encoding a two-component system; hrps encoding a transcriptional factor of the ntrc family and hrpl encoding an alternative sigma factor. results obtained suggest the following signal transduction model for activating the hrp regulon: phosphorylated hrpy activates hrps, hrp ... | 2003 | 12650456 |
| the presence of diverse is elements and an avrpphd homologue that acts as a virulence factor on the pathogenicity plasmid of erwinia herbicola pv. gypsophilae. | the pathogenicity of erwinia herbicola pv. gypsophilae (ehg) and erwinia herbicola pv. betae (ehb) is dependent on a native plasmid (ppath(ehg) or ppath(ehb)) that harbors the hrp gene cluster, genes encoding type iii effectors, phytohormones, biosynthetic genes, and several copies of is1327. sequence analysis of the hrp-flanking region in ppath(ehg) (cosmid pla150) revealed a cluster of four additional is elements designated as isehel, isehe2, isehe3, and isehe4. two copies of another is elemen ... | 2002 | 12118887 |
| the operon for cytokinin biosynthesis of erwinia herbicola pv. gypsophilae contains two promoters and is plant induced. | the operon for cytokinin biosynthesis in the gall-forming bacterium erwinia herbicola pv. gypsophilae (ehg) has been previously shown to reside on an indigenous plasmid (ppath(ehg)) that is mandatory for pathogenicity. this operon consists of two genes: the first open reading frame (pre-etz) is of unknown function, whereas the second one (etz) encodes for isopentenyl transferase. northern hybridization performed with the wild-type strain ehg824-1 grown in luria-bertani broth demonstrated two tra ... | 2001 | 11822839 |
| effects of the two-component system comprising gaca and gacs of erwinia carotovora subsp. carotovora on the production of global regulatory rsmb rna, extracellular enzymes, and harpinecc. | posttranscriptional regulation mediated by the regulator of secondary metabolites (rsm) rsma-rsmb pair is the most important factor in the expression of genes for extracellular enzymes and harpinecc in erwinia carotovora subsp. carotovora. rsma is a small rna-binding protein, which acts by lowering the half-life of a mrna species. rsmb specifies an untranslated regulatory rna and neutralizes the rsma effect. it has been speculated that gaca-gacs, members of a two-component system, may affect gen ... | 2001 | 11310739 |
| genetic organization of the hrp gene cluster and dspae/bf operon in erwinia herbicola pv. gypsophilae. | erwinia herbicola pv. gypsophilae induces gall formation in gypsophila that is dependent on the existence of a pathogenicity plasmid (ppathehg). we previously demonstrated the presence of several hrp genes on this plasmid. by employing transposon mutagenesis and sequencing, a functional hrp gene cluster on the ppathehg has now been characterized completely. the hrp genes of e. herbicola pv. gypsophilae are remarkably similar to and colinear with those of erwinia amylovora and pantoea stewartii a ... | 2001 | 11277443 |
| a pathogenicity gene isolated from the ppath plasmid of erwinia herbicola pv. gypsophilae determines host specificity. | the host range of the gall-forming bacterium erwinia herbicola pv. gypsophilae (ehg) is restricted to the gypsophila plant whereas e. herbicola pv. betae (ehb) incites galls on beet as well as gypsophila. the pathogenicity of ehg and ehb was previously shown to be dependent on a plasmid (ppath). transposon mutagenesis was used to generate mutants on the cosmid pla150 of the ppath from ehg824-1. a cluster of nonpathogenic mutations flanked by two is1327 elements was identified on a 3.2-kb ndei dn ... | 1998 | 9675891 |
| differential involvement of indole-3-acetic acid biosynthetic pathways in pathogenicity and epiphytic fitness of erwinia herbicola pv. gypsophilae. | erwinia herbicola pv. gypsophilae (ehg), which induces galls on gypsophila paniculata, harbors two major pathways for indole-3-acetic acid (iaa) synthesis, the indole-3-acetamide (iam) and indole-3-pyruvate (ipya) routes, as well as cytokinin biosynthetic genes. mutants were generated in which the various biosynthetic routes were disrupted separately or jointly in order to assess the contribution of iaa of various origins and cytokinins to pathogenicity and epiphytic fitness. inactivation of the ... | 1998 | 9650296 |
| the presence of hrp genes on the pathogenicity-associated plasmid of the tumorigenic bacterium erwinia herbicola pv. gypsophilae. | the pathogenicity-associated plasmid (ppath) of erwinia herbicola pv. gypsophilae (ehg), which is present only in pathogenic strains, contains a gene cluster encoding indole-3-acetic acid and cytokinin biosynthesis. the transposon-reporter tn3-spice was used to generate nonpathogenic mutants on two overlapping cosmids, pla150 and pla352, of the ppath. a cluster of such mutations, which spanned 16 kb, mapped approximately 15 kb from the gene cluster involved in phytohormone biosynthesis. non-path ... | 1997 | 9204571 |
| the genes involved in cytokinin biosynthesis in erwinia herbicola pv. gypsophilae: characterization and role in gall formation. | a locus conferring cytokinin production was previously isolated from the gall-forming bacterium erwinia herbicola pv. gypsophilae. this locus resided in a cluster with the genes specifying indole-3-acetic acid production on the pathogenicity-associated plasmid ppath (a. lichter, s. manulis, o. sagee, y. gafni, j. gray, r. meilen, r. o. morris, and i. barash, mol. plant microbe interact., 8:114-121, 1995). sequence analysis of this locus indicated the presence of a cytokinin biosynthesis gene (et ... | 1995 | 7635829 |
| The Type III Effector HsvG of the Gall-Forming Pantoea agglomerans Mediates Expression of the Host Gene HSVGT. | The type III effector HsvG of the gall-forming Pantoea agglomerans pv. gypsophilae (Pag) is a DNA-binding protein that is imported to the host nucleus and involved in host specificity. The DNA-binding region of HsvG was delineated to 266 amino acids located within a secondary structure region near the N-terminus of the protein, but did not display any homology to canonical DNA-binding motifs. A binding site selection procedure was used to isolate a target gene of HsvG, named HSVGT, in Gypsophila ... | 2011 | 21995766 |
| characterization of nuclear localization signals in the type iii effectors hsvg and hsvb of the gall-forming bacterium pantoea agglomerans. | hsvg and hsvb, two paralogous type iii effectors of the gall-forming bacteria pantoea agglomerans pv. gypsophilae and p. agglomerans pv. betae, determine host specificity on gypsophila and beet, respectively. they were previously shown to be dna-binding proteins imported into host and non-host nuclei and might act as transcriptional activators. sequence analysis of these effectors did not detect canonical nuclear localization signals (nlss), but two basic amino acid clusters designated putative ... | 2011 | 21372093 |
| pthg from pantoea agglomerans pv. gypsophilae encodes an avirulence effector that determines incompatibility in multiple beet species. | summary pantoea agglomerans pv. gypsophilae (pag) causes root and crown gall disease on gypsophila, whereas p. agglomerans pv. betae (pab) induces the disease on beet as well as gypsophila. both pathovars harbour a pathogenicity plasmid (ppath(pag) or ppath(pab)) that determines disease development. we have previously isolated and partially characterized a pleiotropic gene from the ppath(pag), designated as pthg, that encodes a virulence factor in gypsophila and an elicitor of a hypersensitive-l ... | 2004 | 20565587 |
| molecular diagnostic procedures for production of pathogen-free propagation material. | production of disease-free propagation material is a major means of controlling most bacterial diseases of plants, particularly when neither resistant clones nor effective chemical treatments are available. for this purpose sensitive, specific and rapid detection methods are required. the advent of molecular biology and, in particular, the polymerase chain reaction (pcr) has opened new ways for the characterization and identification of plant pathogens and the development of disease-management s ... | 2002 | 12449531 |
| the dual function in virulence and host range restriction of a gene isolated from the ppath (ehg) plasmid of erwinia herbicola pv. gypsophilae. | the host range of the gall-forming bacterium erwinia herbicola pv. gypsophilae (ehg) is restricted to gypsophila whereas erwinia herbicola pv. betae (ehb) attacks beet as well as gypsophila. both pathovars contain an indigenous plasmid (ppath(ehg or ppath(ehb)) that harbors pathogenicity genes, including the hrp gene cluster. a cosmid library of ehg824-1 plasmid dna was mobilized into ehb4188 and the transconjugants were screened for pathogenicity on beet. one ehb transconjugant harboring the co ... | 2000 | 10830268 |