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soil as a possible source for the severe fruit rot of guava (psidium guajava l.) due to phytophthora nicotianae var. parasitica (dastur) wat. at kurukshetra (india).severe fruit rot of guava due to phytophthora nicotianae var. parasitica (syn. p. parasitica dastur sensu stricto) was observed during the months of july and august in 1976 at kurukshetra (india). the pathogen was successfully isolated from the soil below the infected fruit trees using ripe guava fruits as baits as well as by using a selective medium at regular intervals for a period of one year. presence of the pathogen in the soil below the guava trees and its isolation from the soil for a per ...1978754575
a comparative study of the morphology and viability of hyphae of penicillium expansum and phytophthora nicotianae during freezing and thawing.the changes in morphology of penicillium expansum link and phytophthora nicotianae van breda de haan during freezing and thawing in a growth medium with and without the cryoprotective additive glycerol were examined with a light microscope fitted with a temperature-controlled stage. viability of 0.5-1.0 mm diameter colonies of both fungi was determined after equivalent rates of cooling to -196 degrees c in the presence or absence of glycerol. in p. expansum shrinkage occurred in all hyphae at ra ...19863794645
effect of antibiotics on certain cell wall degrading enzymes of rhizopus nodosus and phytophthora nicotianae. 19836629841
[effect of metalaxyl on the synthesis of rna, dna and protein in phytophthora nicotianae].metalaxyl is used to control diseases caused by fungi of the order of the perenosporales. we investigated the action of this fungicid eon nucleic acid and protein synthesis in liquid cultures of phytophthora nicotianae. the uptake of 32p, 3h-uridine, 3h-thymidine and 14c-leucine as precursors of nuclei acid and protein synthesis by the mycelium was not inhibited by metalaxyl. rna synthesis as indicated by 3h-uridine incorporation was strongly inhibited (about 80%) by 0.5 micrograms/ml of metalax ...19846741170
induction of defence responses in cultured tobacco cells by elicitors from phytophthora nicotianae.black shank disease of tobacco, nicotianae tabacum, caused by phytophthora nicotianae, is one of the most destructive of soil borne diseases. the present investigation was initiated to study the relative importance of various inducible mechanisms operative in this plant: pathogen interaction. tobacco cells in culture were treated with heat-released soluble cell-wall elicitors from mycelial walls of the pathogen. the timing and intensity of the induced defence responses of the cells with regard t ...19968920638
elicitin 172 from an isolate of phytophthora nicotianae pathogenic to tomato.elicitin 172, an acid protein with elicitor activity, has been isolated in true form from culture filtrates of phytophthora nicotianae, the causal agent of crown and root rot of tomato (lycopersicon esculentum). the m(r) (10,349 +/- 1) of the purified protein, determined by es-ms, is identical to that calculated for parasiticein using the mean isotopic composition and assuming the occurrence of three disulfide bridges. the primary structure of elicitin 172, determined using also maldi-ms experim ...199910192962
early responses in methyl jasmonate-preconditioned cells toward pathogen-derived elicitors.early, signal transduction-related responses in cultured tobacco cells due to methyl jasmonate (meja), a cell-wall-derived elicitor from phytophthora nicotianae and chitosan, were investigated. meja was an effective inducer of lipid peroxidation and lipoxygenase (lox) activity with maximum levels reached within 2 h and 4-8 h, respectively. chitosan and the elicitor induced a transient increase (1-4 h) in lipid peroxidation. conditioning with meja, followed by secondary elicitation, led to a sign ...200010775507
hydrogen peroxide yields during the incompatible interaction of tobacco suspension cells inoculated with phytophthora nicotianae.rates of h(2)o(2) production by tobacco suspension cells inoculated with zoospores from compatible or incompatible races of the pathogen phytophthora nicotianae were followed by direct measurement of oxygen evolution from culture supernatants following catalase addition. rates of ho(2)(*)/o(2)(-) production were compared by following the formation of the formazan of sodium, 3'-[1-[phenylamino-carbonyl]-3,4-tetrazolium]-bis(4-methoxy-6-nitro) benzene-sulfonic acid hydrate. in the incompatible int ...200011027737
nuclear changes in pathogen-infected tomato roots.we have investigated nuclear changes induced in tomato (lycopersicon esculentum) plant roots by two different pathogens, a phytoplasma of the stolbur group and the soil-borne fungus phytophthora nicotianae var. parasitica, using light and electron microscopy as well as flow cytometry. our results show that both pathogens strongly influenced nuclear structure, causing pyknosis and chromatolysis, and induced variations in proportion of nuclear populations with different dna content, increasing the ...200111411861
the role of proline in osmoregulation in phytophthora nicotianae.a cdna encoding delta(1)-pyrroline-5-carboxylate reductase (p5cr), the enzyme that catalyzes the final step in proline biosynthesis in plants and bacteria, has been cloned from the oomycete plant pathogen phytophthora nicotianae. genomic dna blots indicated that p. nicotianae and p. cinnamomi each contain a single p5cr gene, whereas p. infestans contains one or two genes. complementation of a strain of escherichia coli defective in the p5cr protein by the p. nicotianae p5cr cdna confirmed that t ...200211929217
[allelopathic potential of volatile oil from mikania micrantha].mikania micrantha, an exotic plant species, is an important weed in south china. the volatile oil of the weed species had significant biological activities on plants and their pathogens, particularly pyricularia grisea. the results showed that the seeding growth of 6 plant species decreased obviously when exposed to increasing concentration (200, 400, 800, 1600 mg.l-1) of the volatile oil. the fresh weight of all test plants decreased, and the emergence of all test plants delayed for 1-2 days un ...200212557680
single-strand-conformation polymorphism of ribosomal dna for rapid species differentiation in genus phytophthora.single-strand-conformation polymorphism (sscp) of ribosomal dna of 29 species (282 isolates) of phytophthora was characterized in this study. phytophthora boehmeriae, phytophthora botryosa, phytophthora cactorum, phytophthora cambivora, phytophthora capsici, phytophthora cinnamomi, phytophthora colocasiae, phytophthora fragariae, phytophthora heveae, phytophthora hibernalis, phytophthora ilicis, phytophthora infestans, phytophthora katsurae, phytophthora lateralis, phytophthora meadii, phytophth ...200312892637
[chemical composition of volatile oil from chromolaena odorata and its effect on plant, fungi and insect growth].the volatile oil from c. odorata had a significant effect on the growth of plants, fungi and insects. the result showed that the seedling growth of five test plants was obviously inhibited, in the order of ryegrass > chinese cabbage > radish > snap been > rice. the inhibitory effect of the oil at its middle concentration (800 mg.l-1) for pyricularia grisea was the strongest, the next was to phytophthora nicotianae, and the weakest was to fusarium axysporum. the inhibitory percentage was 61.40%, ...200312924132
genes expressed in zoospores of phytophthora nicotianae.the genus phytophthora includes many highly destructive plant pathogens. in many phytophthora species, pathogen dispersal and initiation of plant infection are achieved by motile, biflagellate zoospores that are chemotactically attracted to suitable infection sites. in order to study gene expression in zoospores, we have constructed a cdna library using mrna from zoospores of phytophthora nicotianae. the library was arrayed and screened using probes derived from mycelium or zoospore mrna. more t ...200414652735
construction of a bacterial artificial chromosome library, determination of genome size, and characterization of an hsp70 gene family in phytophthora nicotianae.the oomycete plant pathogen phytophthora nicotianae causes diseases on a wide range of plant species. to facilitate isolation and functional characterization of pathogenicity genes, we have constructed a large-insert bacterial artificial chromosome (bac) library using nuclear dna from p. nicotianae h1111. the library contains 10,752 clones with an average insert size of 90 kb and is free of mitochondrial dna. the quality of the library was verified by hybridization with 37 genes, all of which re ...200414761797
overexpression of a pepper basic pathogenesis-related protein 1 gene in tobacco plants enhances resistance to heavy metal and pathogen stresses.a pepper gene, cabpr1, which encodes basic pathogenesis-related protein 1, has been reported to be strongly induced after ethephon treatment, wounding, and tobacco mosaic virus infection. the potential role of cabpr1 in tolerance of biotic or abiotic stresses was examined in transgenic nicotiana tabacum cv. xanthi plants. overexpression of cabpr1 in tobacco plants enhanced tolerance not only to heavy metal stresses, but also to the oomycete pathogen phytophthora nicotianae, and the bacterial pat ...200515719238
characterisation of manganese superoxide dismutase from phytophthora nicotianae.three polypeptides with manganese superoxide dismutase (mnsod) activity were found in mycelium, zoospores and germinated cysts of phytophthora nicotianae. their relative molecular weights in non-denaturing gels were approximately 34.5, 36 and 50 kda. no evidence for the presence of either iron or copper/zinc sods was detected at any of the developmental stages examined. the level of activity of the mnsod polypeptides was similar in mycelia and spores. degenerate pcr was used to amplify partial g ...200516279411
a synopsis of the occurrence and pathogenicity of phytophthora species in mainland china.to date, 26 species of phytophthora have been reported in mainland china but only 23 are accepted as good taxa. phytophthora nicotianae (p. parasitica) is the single most important species causing over 40 different plant diseases; p. boehmeriae is widespread attacking gossypium, boehmeria, citrus, broussonetia papyrifera and pterocarya stenoptera; p. "fragariae var. oryzo-bladis" is unique to mainland china causing blight of oryza sativa seedlings; p. megasperma sensu lato has been isolated from ...199716283113
zoospore encystment and pathogenicity of phytophthora and pythium species on plant roots.seven plant species (lucerne, maize, oat, sugarbeet, sorghum, tomato, wheat) and 12 pythium and phytophthora species were used in a comparative study designed to investigate the effects of plant and oomycete inter-specific variation on zoospore encystment density and pathogenicity. zoospores showed differential encystment behaviour and they encysted more on dicotyledonous than on monocotyledonous plants. pythium aphanidermatum, p. deliense, and phytophthora nicotianae were the most aggressive sp ...200616338584
induction of plant defense enzymes and phenolics by treatment with plant growth-promoting rhizobacteria serratia marcescens nbri1213.in greenhouse experiments, plant growth-promoting rhizobacteria (pgpr) serratia marcescens nbri1213 was evaluated for plant growth promotion and biologic control of foot and root rot of betelvine caused by phytophthora nicotianae. bacterization of betelvine (piper betle l.) cuttings with s. marcescens nbri1213 induced phenylalanine ammonia-lyase, peroxidase, and polyphenoloxidase activities in leaf and root. qualitative and quantitative estimation of phenolic compounds was done through high-perf ...200616586018
biosynthesis and secretion of cryptogein, a protein elicitor secreted by phytophthora cryptogea.the phytopathogenic fungi phytophthora subspecies elicit hypersensitive-like necroses on their nonhost tobacco (nicotiana tabacum), with the exception of the tobacco pathogen phytophthora nicotianae. in culture, these fungi-except p. nicotianae-secrete proteins, called elicitins, that cause these remote leaf necroses and are responsible for the incompatible reaction. these proteins protect tobacco against invasion by the agent of the tobacco black shank, p. nicotianae, which is unable to produce ...199216668767
gastrodia anti-fungal protein from the orchid gastrodia elata confers disease resistance to root pathogens in transgenic tobacco.diseases of agricultural crops are caused by pathogens from several higher-order phylogenetic lineages including fungi, straminipila, eubacteria, and metazoa. these pathogens are commonly managed with pesticides due to the lack of broad-spectrum host resistance. gastrodia anti-fungal protein (gafp; gastrodianin) may provide a level of broad-spectrum resistance due to its documented anti-fungal activity in vitro and structural similarity to insecticidal lectins. we transformed tobacco (nicotiana ...200616858580
a simple in-vitro 'wet-plate' method for mass production of phytophthora nicotianae zoospores and factors influencing zoospore production.a simple in-vitro 'wet-plate' method for mass-producing phytophthora nicotianae zoospores at > or =1.0 x 10(6) zoospores/ml is described. temperature critically affected zoospore production; 22 degrees c was optimum, while 36 degrees c was completely inhibitory. zoospores being the most important propagule of p. nicotianae, temperature of recycled irrigation water may be manipulated to reduce diseases in irrigated nursery crops.200717683817
characterization of a heat-stable protein with antimicrobial activity from arabidopsis thaliana.a heat-stable protein with antimicrobial activity was isolated from arabidopsis thaliana plants by buffer-soluble extraction and two chromatographic procedures. the results of maldi-tof analysis revealed that the isolated protein shares high sequence identity with aspen sp1. to determine the exact antimicrobial properties of this protein, a cdna encoding the protein was isolated from an a. thaliana leaf cdna library and named aths1. aths1 mrna was induced by exposure to external stresses, such a ...200717720140
study of rhizosphere and phyllosphere bacterial community and resistance to bacterial canker in genetically engineered phytochrome a cherry plants.the cherry rootstock 'colt' line was transformed with a phytochrome a rice gene with the aim of altering light perception. three transgenic events were chosen because of a modified developmental behavior. when red enriched light was supplied horizontally to stems, the pd3 transgenic line showed an increased rate of phytomer formation associated to a superior rate of plant growth compared to wild type (wt). under the same light conditions, the po1 and pa lines were less altered in morphology and ...200818439710
regulation of catalase activity and gene expression during phytophthora nicotianae development and infection of tobacco.plant defence against pathogen attack typically incorporates an oxidative burst involving elevated levels of reactive oxygen species such as hydrogen peroxide. in the present study, we have used an in-gel assay to monitor the activity of the hydrogen peroxide scavenging enzyme, catalase, during asexual development of phytophthora nicotianae and during infection of host tobacco plants. in vitro, catalase activity is highest in sporulating hyphae; in planta, catalase activity increases dramaticall ...200818705863
a species-specific polymerase chain reaction assay for rapid detection of phytophthora nicotianae in irrigation water.abstract phytophthora nicotianae is a common and destructive pathogen of numerous ornamental, agronomic, and horticultural crops such as tobacco, tomato, and citrus. we have developed a species-specific polymerase chain reaction (pcr) assay for rapid and accurate detection of this pathogen in irrigation water, a primary source of inoculum and an efficient means of propagule dissemination. this pcr assay consists of a pair of species-specific primers (pn), customization of a commercial soil dna e ...200318943163
protection of citrus rootstocks against phytophthora spp. with a hypovirulent isolate of phytophthora nicotianae.abstract phytophthora root rot of citrus in florida is caused by phytophthora nicotianae and p. palmivora. a naturally occurring isolate of p. nicotianae (pn117) was characterized as hypovirulent on citrus roots. pn117 infected and colonized fibrous roots, but caused significantly less disease than the virulent isolates p. nicotianae pn198 and p. palmivora pp99. coincident inoculation of rootstock seedlings of cleopatra mandarin (citrus reticulata) or swingle citrumelo (c. paradisi x poncirus tr ...200718943635
thermal inactivation of phytophthora nicotianae.abstract phytophthora nicotianae was added to pasteurized soil at the rate of 500 laboratory-produced chlamydospores per gram of soil and exposed to temperatures ranging from 35 to 53 degrees c for 20 days. the time required to reduce soil populations to residual levels (0.2 propagule per gram of soil or less) decreased with increasing temperatures. addition of cabbage residue to the soil reduced the time required to inactivate chlamydospores. temperature regimes were established to simulate dai ...200018944471
molecular characterization of natural hybrids of phytophthora nicotianae and p. cactorum.abstract hybrid isolates of phytophthora nicotianae x p. cactorum from five different hosts (cyclamen, lavandula, lewisia, primula, and spathiphyllum spp.) were identified by their atypical morphology and their well-defined heterozygous isozyme patterns. the hybrid nature of these isolates was tested by restriction fragment length polymorphism analysis of the internal transcribed spacer (its) region of rdna, generating fragments typical for both p. nicotianae and p. cactorum. in hybrid isolates, ...200018944508
histological comparison of fibrous root infection of disease-tolerant and susceptible citrus hosts by phytophthora nicotianae and p. palmivora.abstract phytophthora nicotianae and p. palmivora infect and cause rot of fibrous roots of susceptible and tolerant citrus rootstocks in florida orchards. the infection and colonization by the two phytophthora spp. of a susceptible citrus host, sour orange (citrus aurantium), and a tolerant host, trifoliate orange (poncirus trifoliata), were compared using light and electron microscopy. penetration by both phytophthora spp. occurred within 1 h after inoculation, regardless of the host species. n ...199818944916
eggs of tylenchulus semipenetrans inhibit growth of phytophthora nicotianae and fusarium solani in vitro.in previous greenhouse and laboratory studies, citrus seedlings infested with the citrus nematode tylenchulus semipenetrans and later inoculated with the fungus phylophthora nicotianae grew larger and contained less fungal protein in root tissues than plants infected by only the fungus, demonstrating antagonism of the nematode to the fungus. in this study, we determined whether eggs of the citrus nematode t. semipenetrans and root-knot nematode meloidogyne arenaria affected mycelial growth of p. ...200219265943
infection of citrus roots by tylenchulus semipenetrans reduces root infection by phytophthora nicotianae.bioassays and whole-plant experiments were conducted to investigate the interaction between tylenchulus semipenetrans and phytophthora nicotianae. both organisms are parasites of the citrus fibrous root cortex. nematode-infected and non-infected root segments were excised from naturally infected field roots and placed on water agar in close proximity to agar plugs of p. nicotianae and then transferred to a phytophthora-selective medium. at 10 and 12 days, 50% fewer nematode-infected segments wer ...200219265961
tylenchulus semipenetrans alters the microbial community in the citrus rhizosphere.infection of citrus seedlings by tylenchulus semipenetrans was shown to reduce subsequent infection of roots by phytophthora nicotianae and to increase plant growth compared to plants infected by only the fungus. hypothetical mechanisms by which the nematode suppresses fungal development include nutrient competition, direct antibiosis, or alteration of the microbial community in the rhizosphere to favor microorganisms antagonistic to p. nicotianae. a test of the last hypothesis was conducted via ...200319265991
isolation and activity of xenorhabdus antimicrobial compounds against the plant pathogens erwinia amylovora and phytophthora nicotianae.broad-spectrum antibiotics produced by symbiotic bacteria [entomopathogenic bacterium (epb)] of entomopathogenic nematodes keep monoxenic conditions in insect cadavers in soil. this study evaluated antibiotics produced by epb for their potential to control plant pathogenic bacteria and oomycetes.200919320949
role of the modification in root exudation induced by arbuscular mycorrhizal colonization on the intraradical growth of phytophthora nicotianae in tomato.we studied the role of modification in root exudation induced by colonization with glomus intraradices and glomus mosseae in the growth of phytophthora nicotianae in tomato roots. plants were grown in a compartmentalized plant growth system and were either inoculated with the am fungi or received exudates from mycorrhizal plants, with the corresponding controls. three weeks after planting, the plants were inoculated or not with p. nicotianae growing from an adjacent compartment. at harvest, p. n ...200919488792
nicotiana plumbaginifolia plants silenced for the atp-binding cassette transporter gene nppdr1 show increased susceptibility to a group of fungal and oomycete pathogens.summary the behaviour of nicotiana plumbaginifolia plants silenced for the atp-binding cassette transporter gene nppdr1 was investigated in response to fungal and oomycete infections. the importance of nppdr1 in plant defence was demonstrated for two organs in which nppdr1 is constitutively expressed: the roots and the petal epidermis. the roots of the plantlets of two lines silenced for nppdr1 expression were clearly more sensitive than those of controls to the fungal pathogens botrytis cinerea ...200919694955
zoosporic plant pathogens produce bacterial autoinducer-2 that affects vibrio harveyi quorum sensing.the frequent coisolation of bacteria with phytophthora and pythium species suggests possible interspecies communication. zoospore-free fluids (zff) from bacteria-free and nutrient-depleted zoospore suspensions were examined to investigate the production of autoinducer-2 (ai-2), a bacterial interspecies signal molecule, by zoosporic oomycetes. zff from phytophthora nicotianae, phytophthora sojae, and pythium aphanidermatum triggered luminescence of the vibrio harve7yi ai-2 reporter, indicating th ...201020002192
effects of hydrostatic pressure, agitation and co2 stress on phytophthora nicotianae zoospore survival.phytophthora nicotianae breda de haan is a common pathogen of ornamental plants in recycled irrigation systems. in a previous study, annual vinca (catharanthus roseus don) inoculated with zoospore suspensions using a co(2)-pressurized sprayer had less foliage blight than plants inoculated using a hand sprayer. here, the impact of hydrostatic pressure, agitation and aeration with co(2) on the survival of p. nicotianae zoospores was examined.201020201053
endophytic fungi diversity of aquatic/riparian plants and their antifungal activity in vitro.two hundred and fourteen endophytic fungi were isolated from 500 segments of aquatic/riparian plants ottelia acuminata, myriophyllum verticillatum, equisetum arvense, cardamine multijuga, and impatiens chinensis. they were identified to 31 taxa in which cladosporium, fusarium, and geotrichum were the dominant genera. among all isolates, 169 (79%) were anamorphic fungi, 1 (0.5%) was an teleomorphic ascomycete and 44 (21%) were sterile mycelia. there were significant differences in the colonizatio ...201020221722
identification of endophytic bacterial strain mgp1 selected from papaya and its biocontrol effects on pathogens infecting harvested papaya fruit.traditional approaches to the control of diseases of papaya fruit rely on the use of synthetic chemicals, which can cause serious human health and environmental problems. endophytes might be used as an alternative to chemicals to effectively control diseases of harvested papaya fruit.201020355035
zoospore density-dependent behaviors of phytophthora nicotianae are autoregulated by extracellular products.phytophthora species are destructive fungus-like plant pathogens that use asexual single-celled flagellate zoospores for dispersal and plant infection. many of the zoospore behaviors are density-dependent although the underlying mechanisms are poorly understood. here, we use p. nicotianae as a model and demonstrate autoregulation of some zoospore behaviors using signal molecules that zoospores release into the environment. specifically, zoospore aggregation, plant targeting, and infection requir ...201020528180
rapid metabolic profiling of nicotiana tabacum defence responses against phytophthora nicotianae using direct infrared laser desorption ionization mass spectrometry and principal component analysis.abstract:201020534155
gene expression in germinated cysts of phytophthora nicotianae.summary the life cycle of phytophthora species contains several distinct asexual developmental stages that are important for plant infection and disease development. these include vegetative growth of filamentous hyphae, production of multinucleate sporangia, motile, uninucleate zoospores and germinated cysts, the stage at which plant colonization is initiated. to understand mechanisms regulating molecular and cellular processes in germinated cysts, differential hybridization analysis of a cdna ...200420565599
[antagonistic mechanisms of trichoderma spp. against phytophthora nicotianae].antagonistic mechanisms of trichoderma viride m3, tv04-2, and t. harzianum thb, were studied against phytophthora nicotianae, the pathogen of stem blight disease on schizonepeta tenuifolia by dual-culture, hydrolase activity, volatile and nonvolatile substances. results indicated that competitive, mycoparasitism and antagonism were the antagonistic mechanisms of three trichoderma spp. against p. nicotianae. hydrolase activity showed that m3 was the highest for beta-1, 3-glucanases activity while ...201020822004
development of scar markers and pcr assays for single or simultaneous species-specific detection of phytophthora nicotianae and pythium helicoides in ebb-and-flow irrigated kalanchoe.phytophthora nicotianae and pythium helicoides are important water-borne oomycete pathogens of irrigated ornamentals particularly ebb-and-flow irrigated kalanchoe in japan. we developed novel pcr-based sequence characterized amplified region markers and assays for rapid identification and species-specific detection of both pathogens in separate pcr reactions or simultaneously in a duplex pcr.201020826191
efficacy of microorganisms selected from compost to control soil-borne pathogens.suppression of soil-borne plant pathogens with compost has been widely studied. compost has been found to be suppressive against several soil-borne pathogens in various cropping systems. however, an increase of some diseases due to compost usage has also been observed, since compost is a product that varies considerably in chemical, physical and biotic composition, and, consequently, also in ability to suppress soil borne diseases. new opportunities in disease management can be obtained by the s ...201021534476
indicator organisms for assessing sanitization during composting of plant wastes.the potential for using plant pathogens and seeds as indicator organisms for assessing sanitization of plant wastes during composting was tested in bench-scale flask and large-scale systems. plasmodiophora brassicae was unsuitable due to high temperature tolerance in dry to moist composts, and detection of viable inoculum post-composting using bioassay plants not corresponding with that using taqman® pcr, possibly due to preservation of nucleic acids at elevated temperatures. several other plant ...201121546235
relationship between epistasis and aggressiveness in resistance of pepper (capsicum annuum l.) to phytophthora nicotianae.this study evaluated the types of gene action governing the inheritance of resistance to phytophthora nicotianae necrosis in populations derived from two crosses involving two susceptible (beldi and nabeul ii) and one resistant (cm334) cultivars of pepper (capsicum annuum l.). populations, composed of pr, ps, f(1) , f (2) , bc (1) pr, and bc (1) ps generations, were inoculated with six p. nicotianae isolates. generation means analysis indicated that an additive-dominance model was appropriate fo ...201021637483
genetic diversity and phylogeny of antagonistic bacteria against phytophthora nicotianae isolated from tobacco rhizosphere.the genetic diversity of antagonistic bacteria from the tobacco rhizosphere was examined by boxair-pcr, 16s-rflp, 16s rrna sequence homology and phylogenetic analysis methods. these studies revealed that 4.01% of the 6652 tested had some inhibitory activity against phytophthora nicotianae. boxair-pcr analysis revealed 35 distinct amplimers aligning at a 91% similarity level, reflecting a high degree of genotypic diversity among the antagonistic bacteria. a total of 25 16s-rflp patterns were iden ...201121686169
[identification and antagonistic activities of an endophytic bacterium mgp3 isolated from papaya fruit].postharvest decay resulted from anthracnose caused by pathogens colletotrichum gloeosporioides and blight diseases caused by phytophthora nicotianae leads to significant loss of papaya fruits. in order to reduce such loss, we isolated endophytic bacteria that may possess powerful antagonistic activities toward these pathogens for effective biological control of anthracnose and blight diseases.201122126080
identification of a mastigoneme protein from phytophthora nicotianae.tripartite tubular hairs (mastigonemes) on the anterior flagellum of protists in the stramenopile taxon are responsible for reversing the thrust of flagellar beat and for cell motility. immunoprecipitation experiments using antibodies directed towards mastigonemes on the flagella of zoospores ofphytophthora nicotianaehave facilitated the cloning of a gene encoding a mastigoneme shaft protein in this oomycete. expression of the gene, designatedpnmas2, is up-regulated during asexual sporulation, a ...201120663714
tobacco mosaic virus infection results in an increase in recombination frequency and resistance to viral, bacterial, and fungal pathogens in the progeny of infected tobacco plants.our previous experiments showed that infection of tobacco (nicotiana tabacum) plants with tobacco mosaic virus (tmv) leads to an increase in homologous recombination frequency (hrf). the progeny of infected plants also had an increased rate of rearrangements in resistance gene-like loci. here, we report that tobacco plants infected with tmv exhibited an increase in hrf in two consecutive generations. analysis of global genome methylation showed the hypermethylated genome in both generations of p ...201020498336
phytophthora nicotianae transformants lacking dynein light chain 1 produce non-flagellate zoospores.biflagellate zoospores of the highly destructive plant pathogens in the genus phytophthora are responsible for the initiation of infection of host plants. zoospore motility is a critical component of the infection process because it allows zoospores to actively target suitable infection sites on potential hosts. flagellar assembly and function in eukaryotes depends on a number of dynein-based molecular motors that facilitate retrograde intraflagellar transport and sliding of adjacent microtubule ...201020451645
leaf carbohydrate metabolism during defense: intracellular sucrose-cleaving enzymes do not compensate repression of cell wall invertase.the significance of cell wall invertase (cwinv) for plant defense was investigated by comparing wild type (wt) tobacco nicotiana tabacum l. samsun nn (snn) with plants with rna interference-mediated repression of cwinv (snn::cwinv) during the interaction with the oomycetic phytopathogen phytophthora nicotianae. we have previously shown that the transgenic plants developed normally under standard growth conditions, but exhibited weaker defense reactions in infected source leaves and were less tol ...200819704530
molecular comparison of natural hybrids of phytophthora nicotianae and p. cactorum infecting loquat trees in peru and taiwan.natural phytophthora hybrids (p. nicotianae x p. cactorum) infecting loquat in peru and taiwan were characterized with aflp (amplified fragment length polymorphism) markers, the internal transcribed spacer (its) region and the phenol acid carboxylase gene (pheca) and inheritance of the mitochondrial cytochrome oxidase i gene (coxi). aflp profiles of two taiwanese isolates recovered in 1995 were polymorphic in approximately 50% of the fragments whereas five peruvian isolates, recovered 2002-2003 ...200919623929
isoenzyme replacement of glucose-6-phosphate dehydrogenase in the cytosol improves stress tolerance in plants.in source leaves of resistant tobacco, oxidative burst and subsequent formation of hypersensitive lesions after infection with phytophthora nicotianae was prevented by inhibition of glucose-6-phosphate dehydrogenase (g6pdh) or nadph oxidases. this observation indicated that plant defense could benefit from improved nadph availability due to increased g6pdh activity in the cytosol. a plastidic isoform of the g6pdh-encoding gene, g6pd, displaying high nadph tolerance was engineered for cytosolic e ...200919416911
overexpression of lipid transfer protein (ltp) genes enhances resistance to plant pathogens and ltp functions in long-distance systemic signaling in tobacco.the lipid signal is essential for the activation of plant defense responses, but downstream components of the signaling pathway are still poorly defined. to investigate the biological functions of pepper lipid transfer protein (ltp), we carried out virus-induced gene silencing (vigs) in pepper, constitutive expression of caltps and grafting experiments in the tobacco plant. suppression of endogenous caltpi and caltpii by vigs, respectively, resulted in enhanced susceptibility to xanthomonas camp ...200919089429
natural hybrids of phytophthora nicotianae and phytophthora cactorum demonstrated by isozyme analysis and random amplified polymorphic dna.abstract three similar isolates of phytophthora (phytophthora sp-h) were obtained from diseased spathiphyllum and primula plants. cultural characteristics did not fit any known description of phytophthora species. the phytophthora sp-h isolates are papillate, are homothallic, possess 80 to 86% amphigynous antheridia, and have a maximum temperature for growth of 36.5 degrees c. isozyme analysis of the phytophthora sp-h isolates revealed a three-banded pattern with malic enzyme and a three-banded ...199818944870
rna interference-mediated repression of cell wall invertase impairs defense in source leaves of tobacco.the significance of cell wall invertase (cwinv) for plant defense was investigated by comparing wild-type tobacco (nicotiana tabacum) samsun nn (snn) with plants with rna interference (rnai)-mediated repression of cwinv (snncwinv). in source leaves of snncwinv, the activity of cwinv was repressed by about 90%. sucrose export and apoplastic carbohydrate levels were significantly reduced, while photosynthesis and dark respiration exhibited little or no change. activities of sucrose synthase and ph ...200818502974
detection of phld gene in some fluorescent pseudomonads isolated from iran and its relative with antifungal activities.fluorescent pseudomonads that produce antibiotic 2,4-diacetylphloroglocinol (2,4-dapg) are important group of pgrp that inhibit a broad spectrum of plant pathogenic fungi. studying on genetic diversity of 2,4-diacetylphloroglucinol-producing fluorescent pseudomonads has been shown with special importance. the first step to investigate the genetic diversity of these bacteria is detecting of the genes required for the biosynthesis of this antibiotic. the objectives of the current study were detect ...200718396832
cloning and characterization of a balsam pear class i chitinase gene (mcchit1) and its ectopic expression enhances fungal resistance in transgenic plants.a balsam pear (momordica charantia l.) chitinase (mcchit1) was purified and sequenced at the n-terminal. the genomic and cdna coding sequences of mcchit1 were cloned by rapid amplification of 3' cdna ends (3'-race) and the y-shaped adaptor dependent extension (yade) method. sequence analysis showed that the mcchit1 protein is a class i chitinase containing a chitin-binding domain and a catalytic domain, but no c-terminal extension. northern blot indicated that the mcchit1 transcription is wound- ...200717485855
rhizosphere pseudomonas sp. strains reduce occurrence of pre- and post-emergence damping-off in chile and tomato in central himalayan region.based on in vitro screening for pgp and anti-mycelial activity against three zoosporic pathogenic oomycetes, pythium aphanidermatum 123, p. aphanidermatum 4746, and phytophthora nicotianae 4747, seven bacterial isolates were selected for field trials on tomato and chile to test for plant growth promotion under natural and artificial disease-infested field sites in both winter and wet seasons. the effectiveness of isolates in the field trials correlated with the in vitro antagonism screening data ...200717160408
phytophthora nicotianae pnpma1 encodes an atypical plasma membrane h+ -atpase that is functional in yeast and developmentally regulated.pnpma1, a gene encoding a putative p-type plasma membrane h(+)-atpase, has been isolated by differential screening of a phytophthora nicotianae germinated cyst cdna library. pnpma1 is differentially expressed during pathogen asexual development with a more than 10-fold increase in expression in germinated cysts, the stage at which plant infection is initiated, compared to vegetative or sporulating hyphae or motile zoospores. pnpma1 proteins are encoded by two closely linked genes that have no in ...200616730200
examination of some morphologically unusual cultures of phytophthora species using a mitochondrial dna miniprep technique and a standardised sporangium caducity assessment.using the mitochondrial dna miniprep technique, the identity of sixteen morphologically unusual cultures allocated to phytophthora nicotianae, phytophthora mexicana or phytophthora porri was determined by comparison with a library of mtdna band patterns obtained from reference cultures. seven cultures were identified as phytophthora nicotianae (including those assigned to phytophthora mexicana and phytophthora porri), six as strains of phytophthora palmivora with small, ovoid, weakly caducous sp ...199716284813
differences in cell death induction by phytophthora elicitins are determined by signal components downstream of map kinase kinase in different species of nicotiana and cultivars of brassica rapa and raphanus sativus.elicitins are small, secreted proteins produced by species of the plant-pathogenic oomycete phytophthora. they induce hypersensitive cell death in most nicotiana species and in some cultivars of brassica rapa and raphanus sativus. in this study, two true-breeding fast cycling b. rapa lines were established that showed severe necrosis (line 7-r) or no visible response (line 18-nr) after treatment with elicitin. unexpectedly, microscopic examination revealed localized cell death in line 18-nr plan ...200515980203
production of monoclonal antibodies against peripheral-vesicle proteins in zoospores of phytophthora nicotianae.a coimmunisation protocol using microsomal fractions from phytophthora nicotianae cells has enhanced the production of monoclonal antibodies directed towards proteins produced during asexual sporulation. over 40% of the antibodies targeted three categories of zoospore peripheral vesicles. five antibodies label the contents of dorsal vesicles, with three of these reacting with two p. nicotianae polypeptides with a relative molecular mass of approximately 100 kda. two antibodies label the contents ...200415221517
functional characterisation of the 1-18 fragment of esculentin-1b, an antimicrobial peptide from rana esculenta.esculentin-1 is a 46-amino acid residue peptide isolated from skin secretions of rana esculenta, displaying the most potent antimicrobial activity among the bioactive molecules found in the secretion, with negligible effects on eukaryotic cell membranes. from skin secretions, the 19-46 fragment of esculentin-1, devoid of antibacterial activity, was also isolated. we studied in detail the activity of the n-terminal fragment (1-18) of esculentin-1 using a synthetic amidated analogue. the results s ...200315019209
genetic characterization of phytophthora nicotianae by the analysis of polymorphic regions of the mitochondrial dna.a new method based on the analysis of mitochondrial intergenic regions characterized by intraspecific variation in dna sequences was developed and applied to the study of the plant pathogen phytophthora nicotianae. two regions flanked by genes trny and rns and trnw and cox2 were identified by comparing the whole mitochondrial genomes of phytophthora infestans, phytophthora ramorum, and phytophthora sojae and amplified using primers designed from the flanking conserved genes. these regions were s ...201121530925
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