| utilization of a thermosensitive episome bearing transposon tn10 to isolate hfr donor strains of erwinia carotovora subsp. chrysanthemi. | a thermosensitive episome bearing the transposon tn10, f(ts)::tn10 lac+, has been successfully transferred from escherichia coli to several wild strains of the enterobacteria erwinia carotovora subsp. chrysanthemi, which are pathogenic on saintpaulia ionantha. in one of these strains, all of the characters controlled by this episome (lac+, tetr, tra+) were expressed, and its replication was stopped at 40 degrees c and above. at 30 degrees c, the episome was easily transferred between strains der ... | 1982 | 6277860 |
| interaction between aspergilli and streptomycetes in the soil of potted indoor plants: a preliminary report (contribution to the epidemiology of human aspergillosis). | the soil of potted ornamental plants as a reservoir for aspergillus species pathogenic for man is of epidemiological and ecological interest. isolation of a. niger as the sole hyphomycete from the soil of potted african violets (saintpaulia ionantha, gesneriaceae), prompted us to look for a. inger on the surface of the roots of this plant. small pieces of the roots were inoculated in the nutrient-free agar-gel with and without antibiotics. on the antibiotic-free gel, a dense growth of streptomyc ... | 1980 | 6769046 |
| role of endoglucanases in erwinia chrysanthemi 3937 virulence on saintpaulia ionantha. | the role of endoglucanases (endoglucanases z and y) in erwinia chrysanthemi pathogenicity on saintpaulia ionantha was assessed by mutagenizing cloned cel genes (celz and cely) and recombining them with the chromosomal alleles. strains with an omega interposon in celz, a deletion in cely, or a double cel mutant were as virulent as the wild-type strain. however, in the strain with a deletion in cely, a delay in the appearance of symptoms was observed, and then maceration progressed as in plants in ... | 1994 | 8113196 |
| characterization of the pell gene encoding a novel pectate lyase of erwinia chrysanthemi 3937. | 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 f ... | 1995 | 8577252 |
| pectate lyase peli of erwinia chrysanthemi 3937 belongs to a new family. | erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pel4, pelb, pelc, peld, and pele genes and a set of secondary pectate lyases, two of which, pell and pelz, have been already identified. we cloned the peli gene, encoding a ninth pectate lyase of e. chrysanthemi 3937. the peli reading frame is 1,035 bases long, corresponding to a protein of 344 amino acids including a typical amino-terminal signal sequence of 19 amino acids. the purified mature peli protein ... | 1997 | 9393696 |
| the pect repressor coregulates synthesis of exopolysaccharides and virulence factors in erwinia chrysanthemi. | erwinia chrysanthemi 3937 synthesizes an exopolysaccharide (eps) composed of rhamnose, galactose, and galacturonic acid. fourteen transcriptional fusions in genes required for eps synthesis, named eps, were obtained by tn5-b21 mutagenesis. eleven of them are clustered on the chromosome and are repressed by pect, a regulator of pectate lyase synthesis. in addition, expression of these fusions is repressed by the catabolite regulatory protein, crp, and induced in low osmolarity medium. the three o ... | 1999 | 9885192 |
| the minimal gene set member msra, encoding peptide methionine sulfoxide reductase, is a virulence determinant of the plant pathogen erwinia chrysanthemi. | peptide methionine sulfoxide reductase (msra), which repairs oxidized proteins, is present in most living organisms, and the cognate structural gene belongs to the so-called minimum gene set [mushegian, a. r. & koonin, e. v., (1996) proc. natl. acad. sci. usa 93, 10268-10273]. in this work, we report that msra is required for full virulence of the plant pathogen erwinia chrysanthemi. the following differences were observed between the wild-type and a msra- mutant: (i) the msra- mutant was more s ... | 1999 | 9927663 |
| characterization of the exopolygalacturonate lyase pelx of erwinia chrysanthemi 3937. | erwinia chrysanthemi 3937 secretes several pectinolytic enzymes, among which eight isoenzymes of pectate lyases with an endo-cleaving mode (pela, pelb, pelc, peld, pele, peli, pell, and pelz) have been identified. two exo-cleaving enzymes, the exopolygalacturonate lyase, pelx, and an exo-poly-alpha-d-galacturonosidase, pehx, have been previously identified in other e. chrysanthemi strains. using a genomic bank of a 3937 mutant with the major pel genes deleted, we cloned a pectinase gene identifi ... | 1999 | 10049400 |
| characterization of a tonb mutation in erwinia chrysanthemi 3937: tonb(ech) is a member of the enterobacterial tonb family. | 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 ... | 2000 | 10931909 |
| soxr-dependent response to oxidative stress and virulence of erwinia chrysanthemi: the key role of sufc, an orphan abc atpase. | erwinia chrysanthemi causes soft-rot disease in a great variety of plants. in addition to the depolymerizing activity of plant cell wall-degrading enzymes, iron acquisition and resistance to oxidative stress contribute greatly to the virulence of this pathogen. here, we studied the pin10 locus originally thought to encode new virulence factors. the sequence analysis revealed six open reading frames that were homologous to the escherichia coli sufa, sufb, sufc, sufd, sufs and sufe genes. sequence ... | 2001 | 11251816 |
| characterization of indigoidine biosynthetic genes in erwinia chrysanthemi and role of this blue pigment in pathogenicity. | 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 mutan ... | 2002 | 11790734 |
| iron deficiency induced by chrysobactin in saintpaulia leaves inoculated with erwinia chrysanthemi. | in this communication, we examine the fate of iron during soft rot pathogenesis caused by erwinia chrysanthemi on its host, saintpaulia ionantha. the spread of soft rot caused by this enterobacterium was previously shown to depend on a functional genetic locus encoding a high-affinity iron assimilation system involving the catechol-type siderophore chrysobactin. leaf intercellular fluid from healthy plants was analyzed with regard to the iron content and its availability for bacterial growth. it ... | 1993 | 12231882 |
| flavohaemoglobin hmpx from erwinia chrysanthemi confers nitrosative stress tolerance and affects the plant hypersensitive reaction by intercepting nitric oxide produced by the host. | host cells respond to infection by generating nitric oxide (no) as a cytotoxic weapon to facilitate killing of invading microbes. bacterial flavohaemoglobins are well-known scavengers of no and play a crucial role in protecting animal pathogens from nitrosative stress during infection. erwinia chrysanthemi, which causes macerating diseases in a wide variety of plants, possesses a flavohaemoglobin (hmpx) whose function in plant pathogens has remained unclear. here we show that hmpx consumes no an ... | 2005 | 15998309 |
| global effect of indole-3-acetic acid biosynthesis on multiple virulence factors of erwinia chrysanthemi 3937. | production of the plant hormone indole-3-acetic acid (iaa) is widespread among plant-associated microorganisms. the non-gall-forming phytopathogen erwinia chrysanthemi 3937 (strain ech3937) possesses iaam (asap16562) and iaah (asap16563) gene homologues. in this work, the null knockout iaam mutant strain ech138 was constructed. the iaa production by ech138 was reduced in m9 minimal medium supplemented with l-tryptophan. compared with wild-type ech3937, ech138 exhibited reduced ability to produce ... | 2007 | 17189441 |
| characterization of the erwinia chrysanthemi gan locus, involved in galactan catabolism. | beta-1,4-galactan is a major component of the ramified regions of pectin. analysis of the genome of the plant pathogenic bacteria erwinia chrysanthemi revealed the presence of a cluster of eight genes encoding proteins potentially involved in galactan utilization. the predicted transport system would comprise a specific porin ganl and an abc transporter made of four proteins, ganfgk(2). degradation of galactans would be catalyzed by the periplasmic 1,4-beta-endogalactanase gana, which released o ... | 2007 | 17644603 |
| dynamic regulation of gaca in type iii secretion, pectinase gene expression, pellicle formation, and pathogenicity of dickeya dadantii (erwinia chrysanthemi 3937). | dickeya dadantii (erwinia chrysanthemi 3937) secretes exoenzymes, including pectin-degrading enzymes, leading to the loss of structural integrity of plant cell walls. a type iii secretion system (t3ss) is essential for full virulence of this bacterium within plant hosts. the gacs/gaca two-component signal transduction system participates in important biological roles in several gram-negative bacteria. in this study, a gaca deletion mutant (ech137) of d. dadantii was constructed to investigate th ... | 2008 | 18052890 |
| soft rot erwiniae: from genes to genomes. | summary the soft rot erwiniae, erwinia carotovora ssp. atroseptica (eca), e. carotovora ssp. carotovora (ecc) and e. chrysanthemi (ech) are major bacterial pathogens of potato and other crops world-wide. we currently understand much about how these bacteria attack plants and protect themselves against plant defences. however, the processes underlying the establishment of infection, differences in host range and their ability to survive when not causing disease, largely remain a mystery. this rev ... | 2003 | 20569359 |
| fusarium foetens, a new species pathogenic to begonia elatior hybrids (begonia x hiemalis) and the sister taxon of the fusarium oxysporum species complex. | a new disease recently was discovered in begonia elatior hybrid (begonia × hiemalis) nurseries in the netherlands. diseased plants showed a combination of basal rot, vein yellowing and wilting and the base of collapsing plants was covered by unusually large masses of fusarium macroconidia. a species of fusarium was isolated consistently from the discolored veins of leaves and stems. it differed morphologically from f. begoniae, a known agent of begonia flower, leaf and stem blight. the fusarium ... | 2004 | 21148861 |
| fluorescent analysis for bioindication of ozone on unicellular models. | unicellular model plant systems (vegetative microspores of horsetail equisetum arvense and pollen of six plant species corylus avellana, dolichothele albescens populus balsamifera, salix caprea, saintpaulia ionantha, tulipa hybridum, on which autofluorescence and fluorescence after histochemical treatment studied, have been represented as bioindicators of ozone. it has found that low doses of ozone 0.005 or 0.008 μl/l did not affect or stimulate the autofluorescence of the samples with the abili ... | 2015 | 25779939 |
| allergic sensitization to ornamental plants in patients with allergic rhinitis and asthma. | ornamental plants (ops) can lead to immediate-type sensitization and even asthma and rhinitis symptoms in some cases. this study aimed to evaluate sensitization to ops in patients with asthma and/or allergic rhinitis and to determine the factors affecting the rate of sensitization to ops. a total of 150 patients with asthma and/or allergic rhinitis and 20 healthy controls were enrolled in the study. demographics and disease characteristics were recorded. skin-prick tests were performed with a st ... | 2016 | 24717779 |
| relative sensitivity of greenhouse pot plants to long-term exposures of no- and no2-containing air. | thirty-five cultivars of pot plants of 20 families were exposed for 50-64 days in a greenhouse facility to either 1 microl litre(-1) no with 0.5 microl litre(-1) no2, or 1 microl litre(-1) no2 with 0.1 microl litre(-1) no for 15 h each day, with air which was free from these gases as the reference. a sensitivity ranking of the pot plants was compiled, with the highest priority on visible injuries, followed by growth reductions, primarily as a response to the no-dominated exposures, simulating th ... | 1994 | 15091658 |
| cold-induced sudden reversible lowering of in vivo chlorophyll fluorescence after saturating light pulses : a sensitive marker for chilling susceptibility. | in chilling-sensitive plants (glycine max, saintpaulia ionantha, saccharum officinarum) a sudden reversible drop in chlorophyll fluorescence occurs during photosynthetic induction immediately following saturating light pulses at low temperatures in the range 4 to 8 degrees c. a comparison of two soybean cultivars of different chilling sensitivities revealed that this phenomenon, termed lowwave, indicates specific thresholds of low temperature stress. its occurrence under controlled chilling can ... | 1989 | 16666615 |