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studies on the sporulation of phytophthora parasitica dastur var. piperina dast. responsible for leaf and foot-rot of pan, piper betle. l. 196113716994
sterol induction of reproduction and stimulation of growth of pythium and phytophthora.sterols of fungal, plant, and animal origin induced sexual reproduction in pythium periplocum and phytophthora megasperma var. sojae and the formation of large zoosporangia in phytophthora parasitica var. nicotianae. some sterols, especially cholesterol, stimulated growth.196414137942
ultrastructural changes during zoospore formation in phytophthora parasitica. 19674168773
serological differentiation of pythium aphanidermatum from phytophthora parasitica var. nicotiane and ph parasitica. 19676030060
cation and sterol effects on growth of phytophthora parasitica var. nicotianae. 19694985015
fine structure of phytophthora parasitica zoospores. 19695772251
sterol or calcium requirement by phytophthora parasitica var. nicotianae for growth on nitrate nitrogen. 19705441001
ultrastructural aspects of encystation and cyst-germination in phytophthora parasitica. 19715565061
efficacy of certain antibiotics against phytophthora parasitica var. piperina causing leaf-rot of pan. 19734786731
production of oospores by phytophthora parasitica in liquid medium. 19744444724
activity of some antibiotics against phytophthora parasitica var. piperina, incitant of foot-rot and leaf-rot of pan. 19751236088
polar lipids of phytophthora parasitica var. nicontianae, in comparison with those of other selected fungi. 1976133289
organic amendments and control of foot rot of piper betle caused by phytophthora parasitica var. piperina.experiments have been performed to control foot rot of piper betle by organic amendments and antagonists in soil. soil amended with corn straw gave best control. corn straw supplemented with nitrogen (nh4no3) gave still better control. the effect of different antagonists growing on corn-straw and til (sesamum indicum) oil cake amendments showed that trichoderma viride gave best control. aspergillus terreus failed to control the disease although it showed great antifungal activity under controlle ...1976952442
lack of kestose (fructosylcucrose) production by race 3 of phytophthora parasitica var. nicotianae differentiates it from races 0 and 1. 1977895761
production of kestoses (fructosylsucroses) by phytophthora parasitica var. nicotianae.the synthesis of kestoses (trisaccharides composed of two fructose units and one glucose unit) by races 0 and 1 of phytophthora parasitica var. nicotianae is shown. the trisaccharide is found in culture filtrates of isolates grown in liquid media containing 3% sucrose. the utilization of sucrose and trisaccharide formation by the organisms over a 16-day period is described. the kestoses were identified by chemical and enzymatic analysis, and two of three possible isomers were found.197716345201
an examination of enzyme production of phytophthora spp. on solid and liquid media.solid media were used to determine which extracellular hydrolytic enzymes are produced by phytophthora parasitica; p. parasitica var. nicotianae, races 0, 1, and 3; and several other phytophthora spp. most isolates produced rnase, dnase, phosphatase, lipase, and cellulase uniformly. all race 3 isolates of p. parasitica var. nicotianae exhibited protease activity on a medium containing gelatin, while only 33 and 60% of the race 0 and 1 isolates, respectively, and 14% of the p. parasitica isolates ...1978754880
modification of disease resistance of tobacco callus tissues by cytokinins.the effects of differing cytokinin and auxin concentrations on resistance of tobacco (nicotiana tabacum l.) tissue cultures to race 0 of phytophthora parasitica var. nicotianae were examined. with 1 micromolar kinetin and either 11.5 micromolar indoleacetic acid or 1 micromolar 2,4-dichlorophen-oxyacetic acid, tissues from resistant cultivars exhibited a "hypersensitive" reaction to zoospores of the fungus and subsequently were colonized only slightly. with susceptible cultivars or with tissues ...197816660551
interaction of a hydroxyproline-rich glycoprotein from tobacco callus with potential pathogens.a hydroxyproline-rich glycoprotein was isolated from tobacco (nicotiana tabacum l.) callus tissue cultures by an acidic-ethanol extraction procedure and purified to about 95% homogeneity by ion exchange chromatography on carboxymethyl cellulose. this glycoprotein agglutinated cells of an avirulent strain (b-1) of the bacterial pathogen pseudomonas solanacearum but not its parental, virulent isolate (k-60). bacterial lipopolysaccharide (from k-60 strain) inhibited this agglutination. the tobacco ...198216662504
[isolation and structural studies of glucans from phytophthora parasitica].several polysaccharides have been isolated from the cell walls of phytophthora parasitica, a phytopathogenic fungus of carnation. the crude polysaccharides were fractionated by successive chromatographies on deae-cellulose, sephadex g-25, concanavalin-a-sepharose and sephadex g-200 columns. the neutral polysaccharides consist of a mixture of beta(1----3, 1----6)-d-glucans whose relative molecular masses varied from 9000 to about 200 000. all these polysaccharides have a main chain of beta(1----3 ...19846745270
an extracellular protein from phytophthora parasitica var nicotianae is associated with stress metabolite accumulation in tobacco callus.the most abundant extracellular protein produced by phytophthora parasitica var nicotianae at early stages of rapid growth in culture has a molecular weight of 46 kilodaltons and has been designated ppn 46e. culture conditions for the production of this protein have been optimized and the protein has been purified by gel filtration and ion-exchange chromatography. ppn 46e is a soluble, acidic protein (pi 4.67). the amino acids asx (aspartic acid or asparagine), alanine, glycine, glx (glutamic ac ...198716665769
induction of sesquiterpene cyclase and suppression of squalene synthetase activities in plant cell cultures treated with fungal elicitor.addition of elicitor, cell wall fragments of the fungus phytophthora parasitica, to tobacco cell suspension cultures (nicotiana tabacum) resulted in the rapid synthesis and secretion of large amounts of antibiotic sesquiterpenoids. pulse-labeling experiments with [(14)c]acetate and [(3)h] mevalonate demonstrated that the induction of sesquiterpenoid biosynthesis, maximal by 6 to 9 hours after elicitor addition to the cell cultures, was paralleled by a rapid and large decline in the incorporation ...198816666457
antitumoral and immunological properties of a beta-1,3/1,6-glucan from phytophthora parasitica. 198817265352
antitumor active beta-d-glucans from phytophthora parasitica. 19883378236
induction of proteinase inhibitors in tobacco cell suspension culture by elicitors of phytophthora parasitica var. nicotianae.an elicitor preparation obtained from phytophthora parasitica var. nicotianae, a pathogen of tobacco, induced an accumulation of proteinase inhibitors and a stimulation of ethylene synthesis in a tobacco (nicotiana tabacum) cell suspension culture. about 30 micrograms per milliliter of elicitor were necessary for maximal induction of proteinase inhibitor accumulation, and the response was detectable after 12 hours of incubation with elicitor. accumulation of proteinase inhibitors required de nov ...198916666852
antimicrobial activity of naphthoquinones from fusaria.twenty-two naphthoquinone compounds isolated or derived synthetically from culture extracts of fusarium solani and f. oxysporum were examined for antimicrobial activity. fifteen exhibited antibiotic activity against staphylococcus aureus, and 12 were active against streptococcus pyogenes, but none were active at the highest rate of 128 micrograms/ml against escherichia coli, klebsiella pneumoniae, salmonella typhi, proteus vulgaris, serratia marcescens, or pseudomonas aeruginosa. of 8 plant path ...19902233983
tandem arrangement of trna(asp)-encoding genes in phytophthora spp.we have cloned a region of repetitive dna from the phytopathogenic fungus, phytophthora parasitica. the cloned region consists of 17 highly homologous units arranged in tandem. the consensus sequence is 562 bp long and carries the information for a trna(asp). all sequence motifs required for efficient rna polymerase iii transcription are present, and the trna derived from the nucleotide sequence is able to form a complete cloverleaf structure with high homology to previously characterized trna(a ...19911864509
the trp1 gene of phytophthora parasitica encoding indole-3-glycerolphosphate synthase-n-(5'-phosphoribosyl)anthranilate isomerase: structure and evolutionary distance from homologous fungal genes.the trp1 gene was isolated from the genome of phytophthora parasitica. it encodes bifunctional enzyme of the tryptophan biosynthetic pathway indole-3-glycerolphosphate synthase-n-(5'-phosphoribosyl)anthranilate isomerase (igps-prai). the gene was localized and sequenced using random in vitro insertions of omega interposon. the domain structure of the protein product was found to be similar to that of enteric bacteria but different from the structure of homologous enzymes in fungi. two introns in ...19911756978
genetic transformation of the plant pathogens phytophthora capsici and phytophthora parasitica.phytophthora capsici and p.parasitica were transformed to hygromycin b resistance using plasmids pcm54 and phl1, which contain the bacterial hygromycin b phosphotransferase gene (hph) fused to promoter elements of the ustilago maydis heat shock hsp70 gene. enzymes driselase and novozyme 234 were used to generate protoplasts which were then transformed following exposure to plasmid dna and polyethylene glycol 6000. transformation frequencies of over 500 transformants per micrograms of dna per 1 x ...19911651483
responses of cultured tobacco cells to cryptogein, a proteinaceous elicitor from phytophthora cryptogea: possible plasmalemma involvement.in culture, the phytopathogenic fungus phytophthora cryptogea secretes a protein which elicits hypersensitive-like necroses and protects tobacco plants against invasion by the pathogen phytophthora parasitica var. nicotianae. this protein, named cryptogein, has been purified and its amino acid sequence determined. in this work, we studied the effect of cryptogein on tobacco cell suspension cultures. cryptogein was lethal at about 0.10 micromolar. when added at sublethal doses, it elicited the pr ...199116668010
genetic code and phylogenetic origin of oomycetous mitochondria.we sequenced the 3'-terminal part of the cox3 gene encoding cytochrome c oxidase subunit 3 from mitochondria of phytophthora parasitica (phylum oomycota, kingdom protoctista). comparison of the sequence with known cox3 genes revealed that ugg is used as a tryptophan codon in contrast to uga in the mitochondrial codes of most organisms other than green plants. a very high at mutation pressure operates on the mitochondrial genome of phytophthora, as revealed by codon usage and by a+t content of no ...19921588598
increased tolerance to two oomycete pathogens in transgenic tobacco expressing pathogenesis-related protein 1a.expression of pathogenesis-related protein 1a (pr-1a), a protein of unknown biochemical function, is induced to high levels in tobacco in response to pathogen infection. the induction of pr-1a expression is tightly correlated with the onset of systemic acquired resistance (sar), a defense response effective against a variety of fungal, viral, and bacterial pathogens. while pr-1a has been postulated to be involved in sar, and is the most highly expressed of the pr proteins, evidence for its role ...19938346252
a gene encoding a host-specific elicitor protein of phytophthora parasitica.extracellular elicitor proteins (elicitins) from phytophthora species induce local and distal defense responses specifically in plants of the solanaceae and cruciferae. based on elicitin amino acid sequences, elicitin-coding sequences from p. parasitica were amplified by the polymerase chain reaction. a genomic clone containing a complete elicitin gene, para1, was isolated and sequenced. elicitin was confirmed to be encoded as a precursor protein containing a 20-amino acid signal peptide that is ...19938274771
two widely accessible media for growth and reproduction of phytophthora and pythium species.tomato agar and soybean agar were found to be comparable to or in some cases better than the popular v8 vegetable juice agar in supporting linear growth of phytophthora cactorum, phytophthora capsici, phytophthora parasitica, pythium aphanidermatum, and pythium splendens; sporangium production of p. capsici, p. palmivora, and pythium splendens; and oospore formation of p. cactorum, p. parasitica, pythium aphanidermatum and pythium splendens. these two media with readily accessible ingredients ca ...199316349002
mutations affecting hyphal colonization and pyoverdine production in pseudomonads antagonistic toward phytophthora parasitica.in previous studies, pseudomonas putida 06909 and pseudomonas fluorescens 09906 suppressed populations of phytophthora parasitica in the citrus rhizosphere, suggesting that these bacteria may be useful in biological control of citrus root rot. in this study we investigated the mechanisms of antagonism between the bacteria and the fungus. both bacteria colonized phytophthora hyphae and inhibited the fungus on agar media. a hyphal column assay was developed to measure the colonization of bacteria ...199416349177
potential role of elicitins in the interaction between phytophthora species and tobacco.the potential role of extracellular elicitor proteins (elicitins) from phytophthora species as avirulence factors in the interaction between phytophthora and tobacco was examined. a survey of 85 phytophthora isolates representing 14 species indicated that production of elicitin is almost ubiquitous except for isolates of phytophthora parasitica from tobacco. the production of elicitins by isolates of p. parasitica correlated without exception with low or no virulence on tobacco. genetic analysis ...199416349258
osmotin overexpression in potato delays development of disease symptoms.transgenic potato and tobacco plants carrying the osmotin gene under the control of the cauliflower mosaic virus 35s promoter constitutively overexpressed osmotin to a level of approximately 2% of total cellular protein. leaves of transgenic potato plants exhibited delayed development of disease symptoms after inoculation with spore suspensions of phytophthora infestans, which is the cause of late blight disease of potato. in contrast, transgenic tobacco plants did not display any change in the ...199411607463
pcr amplification of species-specific dna sequences can distinguish among phytophthora species.we used pcr to differentiate species in the genus phytophthora, which contains a group of devastating plant pathogenic fungi. we focused on phytophthora parasitica, a species that can infect solanaceous plants such as tomato, and on phytophthora citrophthora, which is primarily a citrus pathogen. oligonucleotide primers were derived from sequences of a 1,300-bp p. parasitica-specific dna segment and of an 800-bp p. citrophthora-specific segment. under optimal conditions, the primers developed fo ...19948074533
structural features of fungal beta-d-glucans for the efficient inhibition of the initiation of virus infection on nicotiana tabacum.glucans of fungal origin have been shown to inhibit the early stages of infection of nicotiana by numerous viruses of different taxonomic groups. several glucans were isolated from the cell walls of phytophthora parasitica, phytophthora megasperma f. sp. glycinea (pmg) and fusarium oxysporum, and their antiviral activity compared on tobacco leaves inoculated with tobacco mosaic virus. these polysaccharides consist of a mixture of (1-->3)(1-->6)-beta-d-glucans with m(r) varying from 1.1 x 10(3) t ...19957786491
elicitin produced by an isolate of phytophthora parasitica pathogenic to tobacco.elicitin was prepared from a phytophthora parasitica culture isolated from tobacco in australia. the protein with elicitor activity was purified and sequenced. this protein, which contains 98 amino acid residues, shows full homology with an elicitin produced by a completely unrelated isolate from carnation, indicating conservation of elicitin sequence within a single species.19957766061
new antibiotics phthoxazolins b, c and d produced by streptomyces sp. ko-7888.new antibiotics, phthoxazolins b, c and d were isolated from the fermentation broth of streptomyces sp. ko-7888. they are geometrical isomers of 10-hydroxyphthoxazolin a. they showed selective antifungal activity against phytophthora parasitica in vitro and modest herbicidal activity in a laboratory test, but the potencies were different among isomers.19957649873
characterization of a gene cluster of phytophthora cryptogea which codes for elicitins, proteins inducing a hypersensitive-like response in tobacco.elicitins, proteinaceous elicitors secreted by phytophthora spp., act as inducers of a hypersensitive-like response in tobacco during incompatible interactions. we have isolated and cloned sequences encoding cryptogein and related isoforms from p. cryptogea that belong to the elicitin family. the isolation of a genomic clone led to the characterization of four clustered genes. two of these genes encode distinct elicitins, and two genes would encode, if expressed, a class of highly acidic eliciti ...19958664508
lipoxygenase gene expression in the tobacco-phytophthora parasitica nicotianae interaction.a recently isolated cdna clone of tobacco (nicotiana tabacum l.) lipoxygenase (lox) was used to study lox gene expression in tobacco cell-suspension cultures and intact plants in response to infection with phytophthora parasitica nicotianae (ppn). southern blot analysis of tobacco dna indicated that only a small number of lox genes hybridize to this probe. these genes were not constitutively expressed to a detectable level in control cells and healthy plants. in contrast, a rapid and transient a ...19968938408
physiological and molecular characteristics of elicitin-induced systemic acquired resistance in tobacco.elicitins are low molecular weight proteins secreted by all phytophthora species analyzed so far. application of the purified proteins to tobacco nicotiana tabacum leads to the induction of resistance to subsequent inoculations with the black shank-causing agent, phytophthora parasitica var nicotianae. in this paper, we describe the systemic characteristics of elicitin-induced acquired resistance in tobacco. elicitin application is followed by the rapid translocation of the protein in the plant. ...199612226188
purification, elicitor activity, and cell wall localization of a glycoprotein from phytophthora parasitica var. nicotianae, a fungal pathogen of tobacco.abstract a glycoprotein of 34 kda (gp 34) was solubilized at acidic ph from the mycelium of phytophthora parasitica var. nicotianae and was purified by ion exchange and gel permeation chromatography. whole tobacco plants treated with gp 34 through their roots showed an enhanced lipoxygenase activity as well as hydroxyproline-rich glycoprotein accumulation, indicating that this molecule had elicitor properties. an antiserum raised against the pure glycoprotein allowed localization of gp 34 by imm ...199718945060
calcium interference with zoospore biology and infectivity of phytophthora parasitica in nutrient irrigation solutions.abstract calcium, applied as either cacl2 or ca(no3)2 to water or calcium-free soluble fertilizer solution (peters 20-10-20 peat lite special), affected several important stages of phytophthora parasitica zoospore behavior relevant to infection and disease spread. release of zoospores from sporangia was suppressed by ca(2+) concentrations in the range of 10 to 50 meq. these concentrations also curtailed zoospore motility; 20 meq of ca(2+) in fertilizer solution caused all zoospores to encyst wit ...199718945107
cloning and characterization of a cdna encoding an elicitor of phytophthora parasitica var. nicotianae that shows cellulose-binding and lectin-like activities.phytophthora parasitica var. nicotianae produces a 34-kda glycoprotein elicitor (cbel) that is localized in the cell wall. a cdna encoding the protein moiety of this elicitor was cloned and characterized. the deduced amino acid sequence consisted of two direct repeats of a cysteine-rich domain, joined by a thr/pro-rich region. although having no general homology with published sequences, the positions of the cysteine residues in the two repeats show a conserved pattern, similar to that of the ce ...19979390419
mating-type loci segregate aberrantly in phytophthora infestans but normally in phytophthora parasitica: implications for models of mating-type determination.in the oomycete, phytophthora infestans, mating type is determined by a locus that segregates in a non-mendelian manner consistent with its linkage to a system of balanced lethals. the significance of this unusual phenomenon was addressed by studying the segregation patterns of dna markers linked to mating type in the related species, p. parasitica. this was done using loci identified by either rapd analysis of p. parasitica crosses or by cross-hybridization with rflp markers linked to mating ty ...19979309171
isolation and characterization of inositol sphingophospholipids from phytophthora parasitica dastur.several inositol sphingophospholipids (ispl) were isolated from mycelia of phytophthora parasitica dastur, a phytopathogenic fungus of carnation. the ispl structures were determined by fast atom bombardment. all ispl consisted of ceramides linked to inositol phosphate. we investigated the effect of growth conditions on the ispl produced in four different media that are commonly used for fungal cultures. we showed that p. parasitica dastur synthesized four major classes of compounds with molecula ...19979113622
a peroxidase gene promoter induced by phytopathogens and methyl jasmonate in transgenic plants.the expression of two closely related peroxidase isogenes, shpx6a and shpx6b, of the legume stylosanthes humilis was studied using isogene-specific reverse transcriptase pcr techniques. results indicated that transcripts of both genes were rapidly induced following inoculation with the fungal pathogen colletotrichum gloeosporioides, wounding and treatment with the defense regulator methyl jasmonate (meja). in contrast treatment of leaves of s. humilis with abscisic acid (aba) and salicylic acid ...19979100378
rnase activity prevents the growth of a fungal pathogen in tobacco leaves and increases upon induction of systemic acquired resistance with elicitin.the hypersensitive response and systemic acquired resistance (sar) can be induced in tobacco (nicotiana tabacum l.) plants by cryptogein, an elicitin secreted by phytophthora cryptogea. stem application of cryptogein leads to the establishment of acquired resistance to subsequent leaf infection with phytophthora parasitica var nicotianae, the agent of the tobacco black shank disease. we have studied early events that occur after the infection and show here that a tobacco gene encoding the extrac ...19979414563
the incompatible interaction between phytophthora parasitica var. nicotianae race 0 and tobacco is suppressed in transgenic plants expressing antisense lipoxygenase sequences.nicotiana tabacum 46-8 cultivar displays an incompatible interaction with race 0 of phytophthora parasitica var. nicotianae (ppn), a fungal pathogen of most tobacco cultivars. at the plant level, incompatibility is characterized by the induction of lipoxygenase (lox, ec = 1.13.11.12) activity and localized hypersensitive cell death before defense gene activation. to evaluate the involvement of lox in the onset of plant defense, tobacco 46-8 plants were genetically engineered using full-length or ...19989601005
use of a new tetrazolium-based assay to study the production of superoxide radicals by tobacco cell cultures challenged with avirulent zoospores of phytophthora parasitica var nicotianaethe relationship between the production of reactive oxygen species and the hypersensitive response (hr) of tobacco (nicotiana tabacum l. ) toward an incompatible race of the oomycete phytophthora parasitica var nicotianae has been investigated. a new assay for superoxide radical (o2-) production based on reduction of the tetrazolium dye sodium,3'-(1-[phenylamino-carbonyl]-3, 4-tetrazolium)-bis(4-methoxy-6-nitro) benzene-sulfonic acid hydrate (xtt) has enabled the quantitative estimation of perhy ...19989625702
occurrence of a parasexual cycle following the transfer of isolated nuclei into protoplasts of phytophthora parasitica.nuclei isolated from metalaxyl-resistant (mr) protoplasts of phytophthora parasitica were transferred into chloroneb-resistant (cnr) protoplasts of the same species, with an average successful rate of 1x10(-4), using a selective medium containing both metalaxyl and chloroneb. no colonies appeared when self-fusion products of donor nuclei or recipient protoplasts were exposed to the selective medium. similar results were obtained when the reciprocal nuclear transformation was performed. all the z ...19989724414
transmembrane ca2+ fluxes associated with zoospore encystment and cyst germination by the phytopathogen phytophthora parasiticaphytophthora spp. can infect plants within 30 min of a zoospore arriving at a host surface. the infection sequence from zoospore encystment to cyst germination and host penetration seems to be largely preprogrammed and dependent on calcium signaling. here we present evidence that the encystment process leading to autonomous germination in phytophthora parasitica may be coordinated by sequential net ca2+ fluxes across the cell membrane, which we assessed by fluorimetry of the probe fura-2 in zoos ...19989806806
expression of an anther-specific chalcone synthase-like gene is correlated with uninucleate microspore development in nicotiana sylvestris.two cdna clones, specifically expressed in nicotiana sylvestris anthers during uninucleate microspore development, were isolated using a subtractive hybridization approach. sequence analysis showed that one of them, nschslk, displayed a high level of similarity to several anther-specific chalcone synthase-like (chslk) proteins and an orf from chromosome i of arabidopsis thaliana. a lower, but significant, similarity to chalcone synthases and closely related enzymes (chsre) was also detected. the ...19989869422
structural studies of the extracellular beta-d-glucans from phytophthora parasitica dastur.several extracellular glucans have been isolated from phytophthora parasitica dastur, a phytopathogenic fungus of the carnation. these polysaccharides consist of a mixture of (1-->3)(1-->6)-beta-d-glucans whose molecular masses varied from 1 x 10(4) to 5 x 10(6) da. all of these polysaccharides have a main chain of beta-(1-->3)-linked d-glucose residues substituted with mono-, di- and oligo-saccharidic chains attached through (1-->6) linkages.199810209868
diversity of virulence in phytophthora parasitica on tobacco, as reflected by nuclear rflps.abstract a worldwide collection of p. parasitica isolates was investigated for the ability to infect tobacco and tomato, as related to elicitin production. elicitin was produced by all nontobacco isolates, and nonproducing strains all were isolated from tobacco. in addition, producing strains were isolated from tobacco and coexisted with nonproducing (te ) strains. elicitin production generally was associated with low virulence on tobacco and frequent pathogenicity on tomato, whereas te isolates ...199818944966
oocydin a, a chlorinated macrocyclic lactone with potent anti-oomycete activity from serratia marcescens.a unique chlorinated macrocyclic lactone, termed oocydin a, was isolated from a strain of serratia marcescens growing as an epiphyte on rhyncholacis pedicillata, an aquatic plant native to the carrao river of the venezuelan-guyanan region of south america. the lactone has a molecular mass of 470 da, and contains one atom of chlorine, a carboxyl group and a tetrahydrofuran ring internal to a larger macrocyclic ring. mics of approximately 0.03 microg ml(-1) were noted for oocydin a against such ph ...199910627053
green fluorescent protein (gfp) as gene expression reporter and vital marker for studying development and microbe-plant interaction in the tobacco pathogen phythphthora parasitica var. nicotianae.peg-mediated transformation of protoplasts in the presence of lipofectin was achieved in phytophthora parasitica var. nicotianae, an oomycete pathogen of tobacco. using oomycete promoter and terminator sequences, a plant-adapted green fluorescent protein (gfp) was introduced into the microorganism. the data show for the first time that this eukaryotic gene reporter can be used in an oomycete, both as a quantitative reporter of gene induction and as a vital marker allowing the study of developmen ...199910917747
conversion of compatible plant-pathogen interactions into incompatible interactions by expression of the pseudomonas syringae pv. syringae 61 hrma gene in transgenic tobacco plants.the hrma gene from pseudomonas syringae pv. syringae has previously been shown to confer avirulence on the virulent bacterium p. syringae pv. tabaci in all examined tobacco cultivars. we expressed this gene in tobacco plants under the control of the tobacco delta0. 3 tobrb7 promoter, which is induced upon nematode infection in tobacco roots (opperman et al. 1994, science, 263, 221-223). a basal level of hrma expression in leaves of transgenic plants activated the expression of pathogenesis-relat ...200010929114
phytophthora parasitica elicitor-induced reactions in cells of petroselinum crispum.cultured parsley (petroselinum crispum) cells respond to treatment with elicitors derived from different species of the genus phytophthora with transcript accumulation of defense-associated genes and the production of furanocoumarin phytoalexins. pep-25, an oligopeptide fragment of a phytophthora sojae 42-kda cell wall protein, and a cell wall elicitor preparation derived from phytophthora parasitica (pp-elicitor) stimulate accumulation of the same gene transcripts and formation of the same patt ...200010945338
induction of tci 7, a gene encoding a beta-subunit of proteasome, in tobacco plants treated with elicitins, salicylic acid or hydrogen peroxide.we previously isolated, by differential display and 5' race (rapid amplification of cdna ends), cdnas corresponding to genes activated following cryptogein treatment of tobacco cell suspensions, among them tci 7 (tci for tobacco cryptogein induced), a gene encoding a beta-subunit of proteasome. here, we report that tcl 7 was up-regulated in tobacco plants treated with elicitins (cryptogein and parasiticein) that have been shown to induce a systemic acquired resistance (sar). moreover, subsequent ...200010682830
biochemical modifications and transcriptional alterations attendant to sterol feeding in phytophthora parasitica.phytophthora species are eukaryotic sterol auxotrophs that possess the ability to grow, albeit poorly, in the complete absence of sterols. growth of phytophthora is often improved substantially when an exogenous source of sterol is provided. additionally, sterols may be required for sexual and asexual sporulation in phytophthora. our research has been focused on identifying and characterizing the immediate physiological effects following sterol addition to cultures of p. parasitica. through gas ...200010783000
segregation following interspecific transfer of isolated nuclei between phytophthora parasitica and p. capsici.nuclei isolated from metalaxyl-resistant (mr) protoplasts of phytophthora parasitica were transferred into chloroneb-resistant (cnr) protoplasts of phytophthora capsici and vice versa, with an average success rate of 2.6 x 10(-4) (protoplasts with donor nuclei/regenerated protoplasts), using a selective medium containing only the fungicide tolerated by the nuclear donor. no colonies appeared when self-fusion products of donor nuclei or recipient protoplasts were exposed to the selective medium. ...200010872076
genes expressed in pseudomonas putida during colonization of a plant-pathogenic fungus.in vivo expression technology (ivet) was employed to study colonization of phytophthora parasitica by a biological control bacterium, pseudomonas putida 06909, based on a new selection marker. the pyrb gene, which encodes aspartate transcarbamoylase, an enzyme used for pyrimidine biosynthesis, was cloned from p. putida 06909. a pyrb-disrupted mutant did not grow in pyrimidine-deficient media unless it was complemented with pyrbc' behind an active promoter. thirty clones obtained from p. putida 0 ...200010877766
oligandrin. a proteinaceous molecule produced by the mycoparasite pythium oligandrum induces resistance to phytophthora parasitica infection in tomato plants.a low-molecular weight protein, termed oligandrin, was purified to homogeneity from the culture filtrate of the mycoparasitic fungus pythium oligandrum. when applied to decapitated tomato (lycopersicon esculentum mill. var. prisca) plants, this protein displayed the ability to induce plant defense reactions that contributed to restrict stem cell invasion by the pathogenic fungus phytophthora parasitica. according to its n-terminal sequence, low-molecular weight, acidic isoelectric point, ultravi ...200010982451
cytological effects of cellulases in the parasitism of phytophthora parasitica by pythium oligandrum.the ubiquitous oomycete pythium oligandrum is a potential biocontrol agent for use against a wide range of pathogenic fungi and an inducer of plant disease resistance. the ability of p. oligandrum to compete with root pathogens for saprophytic colonization of substrates may be critical for pathogen increase in soil, but other mechanisms, including antibiosis and enzyme production, also may play a role in the antagonistic process. we used transmission electron microscopy and gold cytochemistry to ...200011010874
a leaf lipoxygenase of potato induced specifically by pathogen infection.lipoxygenase (lox) activity has been identified consistently during pathogen-induced defense responses. here we report the involvement of a specific leaf lox gene of potato (solanum tuberosum), designated potlx-3 (genbank/embl accession no. u60202), in defense responses against pathogens. the sequence of potlx-3 does not match any other lox genes of potato and has the greatest match to a tobacco lox gene that contributes to a resistance mechanism against phytophthora parasitica var nicotianae. p ...200011080289
transplantation and subsequent behavior of mitochondria in cells of phytophthora.mitochondria isolated from streptomycin-resistant (s(r)) protoplasts of phytophthora parasitica were transferred into chloramphenicol-resistant (cpr) protoplasts of p. parasitica or phytophthora capsici with an average successful rate of 1.7 x 10(-4), using a selective medium containing streptomycin. no colonies appeared when self-fusion products of donor mitochondria or recipient protoplasts were exposed to the selective medium. mitochondria isolated from cpr protoplasts of p. capsici were also ...200011109486
expression of the shpx2 peroxidase gene of stylosanthes humilis in transgenic tobacco leads to enhanced resistance to phytophthora parasitica pv. nicotianae and cercospora nicotianae.abstract previous research indicated that the constitutive expression of a pathogen-inducible peroxidase gene (shpx6a) from stylosanthes humilis in transgenic plants resulted in enhanced resistance to fungal pathogens ( kazan, k., goulter, k.c., way, h.m. and manners, j.m. (1998) expression of a pathogenesis-related peroxidase of stylosanthes humilis in transgenic tobacco and canola and its effect on disease development. plant sci. 136, 207-217). we have now investigated another pathogen-inducib ...200020572969
nonphytotoxic aluminum-peat complexes suppress phytophthora parasitica.abstract amendment of peat-based potting media with al(2)(so(4))(3) suppresses damping-off of vinca (catharanthus roseus) caused by phytophthora parasitica. the species of aluminum (al) responsible for disease suppression have not been identified. the objective of this study was to determine the effects of amount and ph of al(2)(so(4))(3) amendment solutions on survival of p. parasitica. in separate experiments, peat was amended with al(2)(so(4))(3) solutions adjusted to ph 4 or 6 at either 0.01 ...200118943446
elicitin genes expressed in vitro by certain tobacco isolates of phytophthora parasitica are down regulated during compatible interactions.phytophthora spp. secrete proteins called elicitins in vitro that can specifically induce hypersensitive response and systemic acquired resistance in tobacco. in phytophthora parasitica, the causal agent of black shank, most isolates virulent on tobacco are unable to produce elicitins in vitro. recently, however, a few elicitin-producing p. parasitica strains virulent on tobacco have been isolated. we investigated the potential diversity of elicitin genes in p. parasitica isolates belonging to d ...200111277430
broad-spectrum antimicrobial activity in vitro of the synthetic peptide d4e1.broad-spectrum antimicrobial activity of a synthetic peptide, d4e1, is documented in this paper. d4e1 inhibited the growth of several fungal phytopathogens belonging to four classes-ascomycetes, basidiomycetes, deuteromycetes, and oomycetes, and two bacterial pathogens, pseudomonas syringae pv. tabaci and xanthomonas campestris pv. malvacearum race 18. the minimum inhibitory concentration (mic) of d4e1 required to completely inhibit the growth of all fungi studied ranged from 4.67 to 25 microm. ...200111409968
hsr203 antisense suppression in tobacco accelerates development of hypersensitive cell death.activation of the tobacco gene hsr203 is rapid, highly localized, specific for incompatible plant-pathogen interactions, and strongly correlated with programmed cell death occurring in response to diverse pathogens. functional characterization of hsr203 gene product has shown that hsr203 is a serine hydrolase that displays esterase activity. we show here that transgenic tobacco plants deficient in hsr203 protein exhibit an accelerated hypersensitive response when inoculated with an avirulent str ...200111489189
creation of hybrid vigor through nuclear transplantation in phytophthora.when isolated nuclei of a diploid oomycete, phytophthora parasitica, were fused with protoplasts of another strain of the same species, the regenerated nuclear hybrids grew faster than the parental isolates. such a phenomenon did not occur in hybrids regenerated from mitochondrion-protoplast or protoplast-protoplast fusion products between these two strains. these results indicate that hybrid vigor is the result of the interaction between two different kinds of nuclei, but not between mitochondr ...200111547886
localized versus systemic effect of arbuscular mycorrhizal fungi on defence responses to phytophthora infection in tomato plants.development of biological control for plant diseases is accepted as a durable and environmentally friendly alternative for agrochemicals. arbuscular mycorrhizal fungi (amf), which form symbiotic associations with root systems of most agricultural, horticultural and hardwood crop species, have been suggested as widespread potential bioprotective agents. in the present study the ability of two amf (glomus mosseae and glomus intraradices) to induce local or systemic resistance to phytophthora paras ...200211847251
altered lignin structure and resistance to pathogens in spi 2-expressing tobacco plants.the physiological role of the norway spruce [ picea abies (l.) karst.] spi 2 gene, encoding a defense-related cationic peroxidase was examined in transgenic tobacco (nicotiana tabacum l.). expression of spi 2, under control of the 35s promoter, in tobacco plants resulted in higher total peroxidase activities. the phenotype of the spi 2-transformed lines was normal. the spi 2-transformed lines displayed lignin levels similar to levels in the control line, but with some alteration in lignin histoc ...200211882939
a tobacco s-like rnase inhibits hyphal elongation of plant pathogens.ribonuclease (rnase) ne gene expression is induced in tobacco leaves in response to phytophthora parasitica. using antibodies directed against rnase ne, we demonstrate that rnase ne is extracellular at the early steps of the interaction, while the fungal tip growth is initiated in the apoplastic compartment. after production in pichia pastoris and biochemical purification, we show that the s-like rnase ne inhibits hyphal growth from p. parasitica zoospores and from fusarium oxysporum conidia in ...200211952127
characterization of a stamen-specific cdna encoding a novel plant defensin in chinese cabbage.we isolated a stamen-specific cdna, bsd1 (brassica stamen specific plant defensin 1) that encodes a novel plant defensin peptide in chinese cabbage (brassica campestris l. ssp. pekinensis). plant defensins are antimicrobial peptides containing eight highly conserved cysteine residues linked by disulfide bridges. in bsd1, the eight cysteine residues and a glutamate residue at position 29 are conserved whereas other amino acid residues of the plant defensins consensus sequence are substituted. bsd ...200212139009
over-expression of a seed specific hevein-like antimicrobial peptide from pharbitis nil enhances resistance to a fungal pathogen in transgenic tobacco plants.two hevein-like peptides from the seed of pharbitis nil, designated pharbitis nil antimicrobial peptide 1 (pn-amp1) and pn-amp2, had been purified previously. both exhibit potent in vitro antifungal activity against a broad spectrum of phytopathogenic fungi. we now report the isolation of two cdna clones, designated pnamp-h1 and pnamp-h2, and the corresponding genomic clones encoding these proteins from mature seeds of p. nil. comparison of the deduced amino acid sequence to that of the mature p ...200212369620
the cbel glycoprotein of phytophthora parasitica var-nicotianae is involved in cell wall deposition and adhesion to cellulosic substrates.the cell wall of the oomycete plant pathogen phytophthora parasitica var. nicotianae contains a protein called cbel that shows cellulose-binding (cb), elicitor (e) of defense in plants and lectin-like (l) activities. the biological role of this molecule in phytophthora was investigated by generating transgenic strains suppressed in cbel expression. phenotypic characterization of these strains showed that they were severely impaired in adhesion to a cellophane membrane, differentiation of lobed s ...200212415001
repetitive applications of the biocontrol agent pseudomonas putida 06909-rif/nal and effects on populations of phytophthora parasitica in citrus orchards.abstract pseudomonas putida 06909-rif/nal was applied repetitively during the irrigation season in two citrus orchards over 3 years. in a mature (50-yearold) commercial citrus orchard covering 2.02 ha, weekly applications of pseudomonas putida 06909-rif/nal with an in-field fermentor resulted in soil populations that fluctuated between 2.83 log cfu + 1 per g of soil and 4.35 log cfu + 1 per g of soil. resulting rhizosphere populations of phytophthora parasitica were significantly reduced in 1999 ...200218942963
cytological characterization of elicitin-induced protection in tobacco plants infected by phytophthora parasitica or phytoplasma.abstract elicitins, small proteins secreted by phytophthora and pythium spp., display the ability to induce plant resistance toward pathogens. ultrastructural investigations of cryptogein-treated tobacco plants evidenced host defense responses such as (i) formation of a calcium pectate gel in intercellular spaces of parenchymas, (ii) impregnation of pectin by phenolic compounds in intercellular spaces of phloem bundles, and (iii) accumulation of phloem proteins (p proteins) in the lumen of leaf ...200318944331
synthesis of beta-d-glucose oligosaccharides from phytophthora parasitica.the glucohexaose, beta-d-glcp-(1-->3)-[beta-d-glcp-(1-->3)-beta-d-glcp-(1-->3)-beta-d-glcp-(1-->6)]-beta-d-glcp-(1-->3)-d-glcp, was synthesized as its allyl glycoside via 3+3 strategy. the trisaccharide donor, 2,3,4,6-tetra-o-benzoyl-beta-d-glucopyranosyl-(1-->3)-2,4,6-tri-o-acetyl-beta-d-glucopyranosyl-(1-->3)-2,4,6-tri-o-acetyl-alpha-d-glucopyranosyl trichloroacetimidate (11), was obtained by 3-selective coupling of isopropyl 4,6-o-benzylidene-1-thio-beta-d-glucopyranoside (2) with 2,3,4,6-tet ...200314572720
coordinated regulation of genes for secretion in tobacco at late developmental stages: association with resistance against oomycetes.besides the systemic acquired resistance (sar) induced in response to microbial stimulation, host plants may also acquire resistance to pathogens in response to endogenous stimuli associated with their own development. in tobacco (nicotiana tabacum), the vegetative-to-flowering transition comes along with a susceptibility-to-resistance transition to the causal agent of black shank disease, the oomycete phytophthora parasitica. this resistance affects infection effectiveness and hyphal expansion ...200414764907
tobacco transgenic for the flax rust resistance gene l expresses allele-specific activation of defense responses.tobacco was transformed with three different alleles (l2, l6, and l10) of the flax rust resistance gene l, a member of the toll interleukin-1 receptor, nucleotide-binding site, leucine-rich repeat (tir-nbs-lrr) class of plant disease resistance genes. l6 transgenics had a stunted phenotype, expressed several defense response genes constitutively, and had increased resistance to the fungus cercospora nicotianae and the oomycete phytophthora parasitica pv. nicotianae. l2 and l10 transgenics, with ...200414964536
modulation of the biological activity of a tobacco ltp1 by lipid complexation.plant lipid transfer proteins (ltps) are small, cysteine-rich proteins secreted into the extracellular space. they belong to the pathogenesis-related proteins (pr-14) family and are believed to be involved in several physiological processes including plant disease resistance, although their precise biological function is still unknown. here, we show that a recombinant tobacco ltp1 is able to load fatty acids and jasmonic acid. this ltp1 binds to specific plasma membrane sites, previously charact ...200415356262
overexpression of the ap2/erebp transcription factor opbp1 enhances disease resistance and salt tolerance in tobacco.osmotin promoter binding protein 1 (opbp1), an ap2/erebp-like transcription factor of tobacco (nicotiana tabacum), was isolated using a yeast one-hybrid system. rna gel blot analysis indicated that expression of the opbp1 gene was induced by elicitor cryptogein, nacl, ethephon, methyl jasmonate, as well as cycloheximide. transient expression analysis using an opbp1-egfp fusion gene in onion epidermal cells revealed that the opbp1 protein was targeted to the nuclear. further, electrophoretic mobi ...200415604704
abiotic and biological suppression of phytophthora parasitica in a horticultural medium containing composted swine waste.abstract horticultural potting media have been amended with compost to enhance biological suppression and with al(2)(so(4))(3) to enhance abiotic suppression of plant pathogens, but these factors have not been simultaneously incorporated into the same medium. in this study, the efficacy of aluminum (al)-amended potting medium containing 20% composted swine waste (csw) was assessed for control of phytophthora parasitica (syn. p. nicotianae), a soilborne pathogen causing damping-off of many hortic ...200418943912
cloning and analysis of pppg1, an inducible endopolygalacturonase gene from the oomycete plant pathogen phytophthora parasitica.phytophthora parasitica is an oomycete plant pathogen that causes severe disease in a wide variety of crops. here, we report the isolation of a gene, named pppg1, which encodes an extracellular endopolygalacturonase in p. parasitica. both cdna and a genomic clone were isolated and sequenced. the pppg1 gene showed standard characteristics with respect to core promoter and intron sequences of phytophthora. the predicted protein of pppg1 has a calculated molecular mass of 39.7 kda and a pi value of ...200515749053
expression of a tomato sugar transporter is increased in leaves of mycorrhizal or phytophthora parasitica-infected plants.a full-length cdna clone (lest3), encoding a putative tomato sugar transporter, was isolated from mycorrhizal roots by using a pcr-based approach. based on sequence similarity, conserved motifs and predicted membrane topology, lest3 was classified as a putative monosaccharide transporter of the sugar transporter subgroup of the major facilitator superfamily. southern blot analysis showed that lest3 represents a single-copy gene in tomato. to investigate its function, lest3 was expressed in a hex ...200515772814
plant-induced cell death in the oomycete pathogen phytophthora parasitica.the activation of programmed cell death in the host during plant-pathogen interactions is an important component of the plant disease resistance mechanism. in this study we show that activation of programmed cell death in microorganisms also regulates plant-pathogen interactions. we found that a form of vacuolar cell death is induced in the oomycete phytophthora parasitica--the agent that causes black shank disease in nicotiana tabacum--by extracellular stimuli from resistant tobacco. the single ...200516098223
overexpression in transgenic tobacco reveals different roles for the rice homeodomain gene osbihd1 in biotic and abiotic stress responses.the rice osbihd1 gene encodes a transcriptional factor belonging to the homeodomain class. it had previously been shown to be activated by treatment with benzothiadiazole, a chemical inducer of disease resistance, and in an incompatible interaction between rice and the blast fungus. to allow a better understanding of the function of osbihd1 in plant disease resistance response, the osbihd1 gene in tobacco was overexpressed by agrobacterium-mediated leaf disc transformation with a construct conta ...200516105854
evidence for mitochondrial gene control of mating types in phytophthora.when protoplasts carrying metalaxyl-resistant (mr) nuclei from the a1 isolate of phytophthora parasitica were fused with protoplasts carrying chloroneb-resistant (cnr) nuclei from the a2 isolate of the same species, fusion products carrying mr nuclei were either the a2 or a1a2 type, while those carrying cnr nuclei were the a1, a2, or a1a2 type. fusion products carrying mr and cnr nuclei also behaved as the a1, a2, or a1a2 type. the result refutes the hypothesis that mating types in phytophthora ...200516333332
gene identification in the oomycete pathogen phytophthora parasitica during in vitro vegetative growth through expressed sequence tags.phytophthora parasitica is a soilborne oomycete pathogen capable of infecting a wide range of plants, including many solanaceous plants. in a first step towards large-scale gene discovery, we generated expressed sequence tags (ests) from a cdna library constructed using mycelium grown in synthetic medium. a total of 3568 ests were assembled into 2269 contiguous sequences. functional categorization could be performed for 65.45% of ests. a significant portion of the transcripts encodes proteins of ...200515950158
identification of qtls associated with citrus resistance to phytophthora gummosis.citrus gummosis, caused by phytophthora spp., is an important citrus disease in brazil. almost all citrus rootstock varieties are susceptible to it to some degree, whereas resistance is present in poncirus trifoliata, a closely related species. the objective of this study was to detect qtls linked to citrus phytophthora gummosis resistance. eighty individuals of the f1 progeny, obtained by controlled crosses between sunki mandarin citrus sunki (susceptible) and poncirus trifoliata cv. rubidoux ( ...200616424605
selection of internal control genes for real-time quantitative rt-pcr assays in the oomycete plant pathogen phytophthora parasitica.real-time quantitative reverse transcription-pcr (qrt-pcr) has become one of the most commonly used methods for rna quantification in recent years. to obtain reliable results with biological significance, it is important that qrt-pcr data are normalized with a proper internal control. in this study, 18 housekeeping genes were selected and evaluated for their potential as a suitable internal control for study of gene expression in the oomycete plant pathogen phytophthora parasitica. analysis of q ...200616531084
antisense expression of a nbs-lrr sequence in sunflower (helianthus annuus l.) and tobacco (nicotiana tabacum l.): evidence for a dual role in plant development and fungal resistance.a partial sunflower cdna clone, plfor48, segregating with a resistance marker to plasmopara halstedii, the causal agent of downy mildew, has been cloned from the mildew resistant sunflower line, rha 266. plfor48 encodes a putative protein with a nucleotide-binding site and a leucine-rich repeat domain, showing significant homology with previously cloned resistance genes belonging to the tir-nbs-lrr family. southern blot analysis of non-transgenic sunflower suggests that plfor48 is part of a mult ...200616604458
differential sensitivity of phytophthora parasitica var. nicotianae and thielaviopsis basicola to monomeric aluminum species.abstract aluminum (al) is toxic to many plant pathogens, including thielaviopsis basicola and phytophthora parasitica var. nicotianae. because fungi-toxicity of al has been described in soils over a wide ph range, multiple species of al may be responsible for pathogen suppression. the goals of this work were to determine the sensitivity of t. basicola and p. para-sitica var. nicotianae to al over a range of ph values, quantify the toxicity of monomeric al species to production of sporangia of p. ...200618944434
cellulose binding domains of a phytophthora cell wall protein are novel pathogen-associated molecular patterns.the cellulose binding elicitor lectin (cbel) from phytophthora parasitica nicotianae contains two cellulose binding domains (cbds) belonging to the carbohydrate binding module1 family, which is found almost exclusively in fungi. the mechanism by which cbel is perceived by the host plant remains unknown. the role of cbds in eliciting activity was investigated using modified versions of the protein produced in escherichia coli or synthesized in planta through the potato virus x expression system. ...200616766692
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