| [relations between the fungi gaeumannomyces graminis and phialophora radicicola when growing together outside the host (author's transl)]. | in laboratory model experiments, numerous hyphal adhesions were found to take place between a severe wheat pathogen, g. graminis var. tritici, and a weak wheat pathogen, p. radicicola var, radicicola, and therefore the linear growth of the both fungi is inhibited. when both fungi occur concurrently side by side on celophane, the hyphae of one fungus do not occupy the place colonized before by the other fungus, due to mutual contact. it can be presumed that also direct interaction between hyphae ... | 1979 | 543347 |
| microorganisms in the rhizosphere of wheat colonized by the fungus gaeumannomyces graminis var. tritici. | the population of microorganisms in wheat rhizosphere changed in the presence of the fungus gaeumannomyces graminis var. tritici causing the take-all of wheat. in the majority of cases when the soil was artificially contaminated by the fungus, both the number of bacteria in the rhizosphere and the bacteria/fungi ratio temporarily increased. at the beginning bacteria growing in the presence of nh4+ predominated, later bacteria utilizing organic n-substances prevailed. pseudomonas fluorescens and ... | 1979 | 112016 |
| rhizosphere microflora and colonization of wheat roots by gaeumannomyces graminis var. tritici after foliar application of urea and benomyl. | the effect of foliar application of 2% urea and 0.6% benomyl on changes in colonization of the rhizosphere by microorganisms and of roots by the fungus gaeumannomyces graminis (sacc.) arx et olivier var. tritici walker was followed in vegetation glass-house experiments. treatment with a urea solution resulted in increased counts of bacteria (82%), pseudomonas fluorescens (46%), agrobacterium sp. (31%) and antagonistic bacteria with respect to the used fungus isolate and in a decreased occurrence ... | 1980 | 6777280 |
| contribution of phenazine antibiotic biosynthesis to the ecological competence of fluorescent pseudomonads in soil habitats. | phenazine antibiotics produced by pseudomonas fluorescens 2-79 and pseudomonas aureofaciens 30-84, previously shown to be the principal factors enabling these bacteria to suppress take-all of wheat caused by gaeumannomyces graminis var. tritici, also contribute to the ecological competence of these strains in soil and in the rhizosphere of wheat. strains 2-79 and 30-84, their tn5 mutants defective in phenazine production (phz-), or the mutant strains genetically restored for phenazine production ... | 1992 | 1514808 |
| cloning and heterologous expression of the phenazine biosynthetic locus from pseudomonas aureofaciens 30-84. | pseudomonas aureofaciens strain 30-84 suppresses take-all disease of wheat caused by gaeumannomyces graminis var. tritici. three antibiotics, phenazine-1-carboxylic acid, 2-hydroxyphenazine-1-carboxylic acid, and 2-hydroxyphenazine, were responsible for disease suppression. tn5-induced mutants deficient in production of one or more of the antibiotics (phz-) were significantly less suppressive than the parental strain. cosmids plsp259 and plsp282 from a genomic library of strain 30-84 restored ph ... | 1992 | 1325219 |
| a volatile factor inducing transmissible lysis in gaeumannomyces graminis (sacc.) arx and olivier var. tritici walker. | filtered water extract of gabalong soil with a recent history of take-all in wheat caused lytic plaques to form in agar cultures of a virulent strain of gaeumannomyces graminis var. tritici. the plaques resembled those produced by bdellovibrio on plate seeded with bacteria. however, there was no evidence of the presence of bacteria, viruses, or mycoplasmas. the lytic factor was transmissible in culture filtrates to fresh subcultures of the fungus. exposure of young healthy colonies to sublethal ... | 1975 | 1116042 |
| serotype variability in virus-like particles from gaeumannomyces graminis. | | 1978 | 664213 |
| effect of bacterial polysaccharides on the growth of gaeumannomyces graminis var. tritici and wheat roots. | agrobacterium sp. and related species which in the soil and in the rhizosphere of wheat accompany the fungus gaemannomyces graminis var. tritici and cause take-all of the wheat roots produced polysaccharides in pure cultures (glucans, mannoglucans and galactomannoglucans). these polysaccharides were utilized better by the mycelium of g. graminis than glucose and polysaccharides of plant origin that occurred on the surface of wheat roots (the so-called mucigel). at lower concentrations these bact ... | 1979 | 468081 |
| antifungal metabolites from trichoderma harzianum. | a detailed examination of the metabolites produced in liquid cultures by a strain of trichoderma harzianum, isolated from wheat roots, has resulted in the identification of a further five metabolites. two of these, cyclonerodiol [5] and the octaketide keto diol 6, have previously been isolated from a strain of trichoderma koningii. the structures of the three new octaketide-derived compounds 7, 8, and 10 have been deduced from spectroscopic and chemical studies. all newly isolated compounds show ... | 1993 | 8277317 |
| [in vitro control of sclerotinia sclerotiorum and gaeumannomyces graminis by bacteria of the fluorescent pseudomonas group]. | thirty six fluorescent pseudomonas isolates were obtained from the rhizosphere of sunflower plants. by antibiosis tests, the six more efficient strains in sclerotinia sclerotiorum growth inhibition, were selected. simultaneously, twenty three fluorescent pseudomonas isolates were recuperated from the rhizosphere of wheat plants and the five most efficient strains in growth inhibition of the fungi gaeumannomyces graminis were selected. the strains selected from the rhizosphere of sunflower plants ... | 1993 | 8234734 |
| bw a4c and other hydroxamic acids are potent inhibitors of linoleic acid 8r-dioxygenase of the fungus gaeumannomyces graminis. | linoleic acid is converted to 8r-hydroperoxylinoleic acid by the soluble 8r-dioxygenase of the fungus gaeumannomyces graminis. effects of different lipoxygenase inhibitors on the 8r-dioxygenase were evaluated. three hydroxamic acid derivatives were investigated. bw a4c (n-(3-phenoxycinnamyl)acetohydroxamic acid) was the most potent with an ic50 of 0.2 microm, followed by zileuton (3-10 microm) and linoleate-hydroxamic acid (0.02 mm). two other lipoxygenase inhibitors, nordihydroguaiaretic acid a ... | 1994 | 8206115 |
| an "instant gene bank" method for heterologous gene cloning: complementation of two aspergillus nidulans mutants with gaeumannomyces graminis dna. | we present a novel technique for gene cloning by complementation of mutations in aspergillus nidulans with dna from a heterologous organism, gaeumannomyces graminis. this technique bypasses the time-consuming and difficult construction of gene libraries, making it both rapid and simple. the method relies on recombination between a fungal replicating vector phelp1 and linear g. graminis genomic dna during co-transformation. we were able to complement two out of seven a. nidulans mutants tested an ... | 1994 | 8121400 |
| sequential oxygenation of linoleic acid in the fungus gaeumannomyces graminis: stereochemistry of dioxygenase and hydroperoxide isomerase reactions. | linoleic acid is sequentially oxygenated to (7s,8s)-dihydroxylinoleic acid by dioxygenase and hydroperoxide isomerase activities present in the fungus gaeumannomyces graminis (brodowsky, i. d., hamberg, m., and oliw, e. h., j. biol. chem. 267, 14738-14745 (1992)). linoleic acids stereospecifically deuterated at c-7 and c-8 were prepared by biological desaturation of the corresponding stearates and used to determine the stereochemistry of the hydrogen abstractions occurring in the dioxygenase- an ... | 1994 | 8117115 |
| linoleic acid 8r-dioxygenase and hydroperoxide isomerase of the fungus gaeumannomyces graminis. mechanism of catalysis and inhibition. | | 1994 | 7825856 |
| in vitro and in vivo antagonism of pathogenic turfgrass fungi by streptomyces hygroscopicus strains yced9 and wye53. | disease prevention is a current practice used to minimize fungal diseases of turfgrasses in lawns and golf greens. prevention is accomplished through fungicide applications, and by periodic thatch removal. during the development of a microbial biodethatch product utilizing the lignocellulose-degrading streptomyces hygroscopicus strains yced9 and wye53, we demonstrated using in vitro plate antagonism bioassays that both strains are antagonists of various turfgrass fungal pathogens. these activiti ... | 1999 | 10455494 |
| host range of a plant pathogenic fungus determined by a saponin detoxifying enzyme. | antifungal saponins occur in many plant species and may provide a preformed chemical barrier to attack by phytopathogenic fungi. some fungal pathogens can enzymatically detoxify host plant saponins, which suggests that saponin detoxification may determine the host range of these fungi. a gene encoding a saponin detoxifying enzyme was cloned from the cereal-infecting fungus gaeumannomyces graminis. fungal mutants generated by targeted gene disruption were no longer able to infect the saponin-cont ... | 1995 | 7824933 |
| studies on linoleic acid 8r-dioxygenase and hydroperoxide isomerase of the fungus gaeumannomyces graminis. | linoleic acid is sequentially converted to 7s,8s-dihydroxy-9z,12z-octadecadienoic acid by the 8r-dioxygenase and hydroperoxide isomerase of the fungus gaeumannomyces graminis, which is a common pathogen of wheat. the objective of this study was to separate and characterize the two enzyme activities. the isomerase activity was found mainly in the microsomal fraction of the mycelia and the 8r-dioxygenase in the cytosol. the 8r-dioxygenase could be partially purified by ammonium sulfate precipitati ... | 1995 | 7760687 |
| liquid-culture ph, temperature, and carbon (not nitrogen) source regulate phenazine productivity of the take-all biocontrol agent pseudomonas fluorescens 2-79. | strain 2-79 is a biocontrol agent against take-all, an important disease of wheat caused by gaeumannomyces graminis var. tritici. in the rhizosphere, it produces the antibiotic phenazine 1-carboxylic acid (pca) as the primary means of disease suppression. one barrier to commercial use of phenazine-producing pseudomonads, like strain 2-79, is the lack of liquid-culture technology for mass production. for instance, there is little published research concerning the impact of liquid-culture secondar ... | 1995 | 7576546 |
| comparison of fungi within the gaeumannomyces-phialophora complex by analysis of ribosomal dna sequences. | four ascomycete species of the genus gaeumannomyces infect roots of monocotyledons. gaeumannomyces graminis contains four varieties, var. tritici, var. avenae, var. graminis, and var. maydis. g. graminis varieties tritici, avenae, and graminis have phialophora-like anamorphs and, together with the other gaeumannomyces and phialophora species found on cereal roots, constitute the gaeumannomyces-phialophora complex. relatedness of a number of gaeumannomyces and phialophora isolates was assessed by ... | 1995 | 7574606 |
| purification and characterization of linoleate 8-dioxygenase from the fungus gaeumannomyces graminis as a novel hemoprotein. | the fungus gaeumannomyces graminis, which causes the major root disease of wheat known as "take-all," can metabolize linoleic acid to (8r)-hydroperoxylinoleic acid. the enzyme linoleate 8-dioxygenase abstracts hydrogen and introduces molecular oxygen in an antarafacial way at c-8. we have now purified the enzyme 1000-fold to a specific activity of 1.8 micronol/min/mg of protein. acetone powder of mycelia of g. graminis was subjected to extraction and ammonium sulfate precipitation with solubiliz ... | 1996 | 8662736 |
| sequence complexities of the nuclear and mitochondrial genomes of the take-all fungus, gaeumannomyces graminis var. tritici. | the nuclear (n) and mitochondrial (mt) genomes of the take-all fungus, gaeumannomyces graminis var. tritici, were examined by reassociation kinetics with escherichia coli dna as internal standard. only one kinetic component was detected in each dna, with second-order rate constants of 0.022 m-1 s-1 for ndna and 10.9 m-1 s-1 for mtdna, corresponding to sequence complexities of 29 x 10(6) base pairs and 60 x 10(3) base pairs respectively. | 1983 | 6663284 |
| characterization of an antibiotic produced by a strain of pseudomonas fluorescens inhibitory to gaeumannomyces graminis var. tritici and pythium spp. | the production, isolation, and characterization of an antibiotic substance from cultures of pseudomonas fluorescens 2-79 (nrrl b-15132) is described. p. fluorescens 2-79 originally was isolated from the roots of wheat and is suppressive to the wheat root disease take-all caused by gaeumannomyces graminis var. tritici. the antibiotic was isolated from potato glucose broth cultures of strain 2-79 by solvent extraction. it was purified by silica gel column chromatography and was a greenish yellow, ... | 1986 | 3087284 |
| role of a phenazine antibiotic from pseudomonas fluorescens in biological control of gaeumannomyces graminis var. tritici. | pseudomonas fluorescens 2-79 (nrrl b-15132) and its rifampin-resistant derivative 2-79rn10 are suppressive to take-all, a major root disease of wheat caused by gaeumannomyces graminis var. tritici. strain 2-79 produces the antibiotic phenazine-1-carboxylate, which is active in vitro against g. graminis var. tritici and other fungal root pathogens. mutants defective in phenazine synthesis (phz-) were generated by tn5 insertion and then compared with the parental strain to determine the importance ... | 1988 | 2841289 |
| antimicrobial activities of ferulago essential oils. | essential oils from ferulago asparagifolia boiss., f. galbanifera (miller) w. koch, f. humilis boiss. (endemic), f. trachycarpa boiss. growing in turkey were evaluated against 15 microorganisms for their antifungal and antibacterial activity using an agar tube dilution and microdilution broth susceptibility assay, respectively. the essential oil compositions were investigated by gc/ms. inhibitory effects against escherichia coli, enterobacter aerogenes, candida albicans, gaeumannomyces graminis ... | 2000 | 11204191 |
| definition of tissue-specific and general requirements for plant infection in a phytopathogenic fungus. | although plant diseases are usually characterized by the part of the plant that is affected (e.g., leaf spots, root rots, wilts), surprisingly little is known about the factors that condition the ability of pathogens to colonize different plant tissues. here we demonstrate that the leaf blast pathogen magnaporthe grisea also can infect plant roots, and we exploit this finding to distinguish tissue-specific and general requirements for plant infection. tests of a m. grisea mutant collection ident ... | 2001 | 11277427 |
| relative importance of fluorescent siderophores and other factors in biological control of gaeumannomyces graminis var. tritici by pseudomonas fluorescens 2-79 and m4-80r. | pseudomonas fluorescens 2-79 suppresses take-all, a major root disease of wheat caused by gaeumannomyces graminis var. tritici. the bacteria produce an antibiotic, phenazine-1-carboxylic acid (pca), and a fluorescent pyoverdin siderophore. previous studies have established that pca has an important role in the biological control of take-all but that antibiotic production does not account fully for the suppressiveness of the strain. to define the role of the pyoverdin siderophore more precisely, ... | 1991 | 1838240 |
| genetic analysis of the antifungal activity of a soilborne pseudomonas aureofaciens strain. | pseudomonas aureofaciens q2-87 produces the antibiotic 2,4-diacetophloroglucinol (phl), which inhibits gaeumannomyces graminis var. tritici and other fungi in vitro. strain q2-87 also provides biological control of take-all, a root disease of wheat caused by this fungus. to assess the role of phl in the antifungal activity of strain q2-87, a genetic analysis of antibiotic production was conducted. two mutants of q2-87 with altered antifungal activity were isolated by site-directed mutagenesis wi ... | 1991 | 1660695 |
| a linoleic acid (8r)-dioxygenase and hydroperoxide isomerase of the fungus gaeumannomyces graminis. biosynthesis of (8r)-hydroxylinoleic acid and (7s,8s)-dihydroxylinoleic acid from (8r)-hydroperoxylinoleic acid. | the fungus gaeumannomyces graminis metabolized linoleic acid extensively to (8r)-hydroperoxylinoleic acid, (8r)-hydroxylinoleic acid, and threo-(7s,8s)-dihydroxylinoleic acid. when g. graminis was incubated with linoleic acid under an atmosphere of oxygen-18, the isotope was incorporated into (8r)-hydroxylinoleic acid and 7,8-dihydroxylinoleic acid. the two hydroxyls of the latter contained either two oxygen-18 or two oxygen-16 atoms, whereas a molecular species that contained both oxygen isotop ... | 1992 | 1634517 |
| metabolism of 18:2(n - 6), 18:3(n - 3), 20:4(n - 6) and 20:5(n - 3) by the fungus gaeumannomyces graminis: identification of metabolites formed by 8-hydroxylation and by w2 and w3 oxygenation. | the present study was aimed at developing a cell-free preparation of gaeumannomyces graminis to biosynthesize w2-hydroxy, w3-hydroxy and related metabolites of essential fatty acids. 14c-labelled linoleic acid (18:2(n - 6)), linolenic acid (18:3(n - 3)), arachidonic acid (20:4(n - 6)) and eicosapentaenoic acid (20:5(n - 3)) were incubated with the cytosolic and microsomal fractions and nadph. significant metabolism was only found in the cytosol. the main products were purified by high-performanc ... | 1992 | 1543726 |
| cloning, characterization, and transcription of three laccase genes from gaeumannomyces graminis var. tritici, the take-all fungus. | gaeumannomyces graminis var. tritici, a filamentous ascomycete, is an important root pathogen of cereals that causes take-all disease and results in severe crop losses worldwide. previously we identified a polyphenol oxidase (laccase) secreted by the fungus when induced with copper. here we report cloning and partial characterization of three laccase genes (lac1, lac2, and lac3) from g. graminis var. tritici. predicted polypeptides encoded by these genes had 38 to 42% amino acid sequence identit ... | 2002 | 11872481 |
| stereochemical aspects of fatty acid oxidation: hydroperoxide isomerases. | lipoxygenases catalyze dioxygenation of polyunsaturated fatty acids to produce fatty-acid hydroperoxides. the reaction involves initial stereospecific abstraction of a hydrogen atom from a bis-allylic methylene group followed by antarafacial attack by dioxygen at one of the terminal carbon atoms of the pentadienyl radical. 8(r)-dioxygenase, recently discovered in the fungus gaeumannomyces graminis, catalyzes formation of 8-hydroperoxy derivatives of linoleic and oleic acids by abstracting one hy ... | 1996 | 8901175 |
| a gene that encodes a product with similarity to dioxygenases is highly expressed in teliospores of ustilago maydis. | the phytopathogenic basidiomycete ustilago maydis produces sexual teliospores only after infection of its host plant, maize. to investigate the process of spore formation, we have isolated ssp1, a protein that is abundantly expressed in mature teliospores. the corresponding gene, ssp1, is expressed at low levels in haploid sporidia; however, transcriptional levels are drastically induced in mature teliospores. transcriptional regulation of ssp1 involves positive and negative promoter elements, a ... | 2002 | 12207223 |
| biosynthesis of 8r-hydroperoxylinoleic acid by the fungus laetisaria arvalis. | 8-hydroxylinoleic acid is known to be a fungicidal metabolite formed by the fungus laetisaria arvalis (bowers, w.s. et al. (1986) science 232, 105-106). in the present report, the mechanism of formation of 8-hydroxylinoleic acid was investigated. l. arvalis metabolized [14c]linoleic acid to 8-hydroperoxylinoleic acid and 8-hydroxylinoleic acid as major metabolites. the identification is based on the reduction of the hydroperoxide to an alcohol with stannous chloride and gas chromatography-mass s ... | 1993 | 8504144 |
| detoxification of benzoxazolinone allelochemicals from wheat by gaeumannomyces graminis var. tritici, g. graminis var. graminis, g. graminis var. avenae, and fusarium culmorum. | the ability of phytopathogenic fungi to overcome the chemical defense barriers of their host plants is of great importance for fungal pathogenicity. we studied the role of cyclic hydroxamic acids and their related benzoxazolinones in plant interactions with pathogenic fungi. we identified species-dependent differences in the abilities of gaeumannomyces graminis var. tritici, gaeumannomyces graminis var. graminis, gaeumannomyces graminis var. avenae, and fusarium culmorum to detoxify these allelo ... | 1998 | 9647804 |
| a protein radical and ferryl intermediates are generated by linoleate diol synthase, a ferric hemeprotein with dioxygenase and hydroperoxide isomerase activities. | linoleate diol synthase (lds) was isolated as a hemeprotein from the fungus gaeumannomyces graminis. lds converts linoleate sequentially to 8r-hydroperoxylinoleate (8-hpode) through an 8-dioxygenase by insertion of molecular oxygen and to 7s,8s-dihydroxylinoleate through a hydroperoxide isomerase by intramolecular oxygen transfer. light absorption and epr spectra of lds indicated that the heme iron was ferric and mainly high spin. oxygen consumption during catalysis started after a short time la ... | 1998 | 9694817 |
| linoleate diol synthase of the rice blast fungus magnaporthe grisea. | mycelia of two strains of magnaporthe grisea, guy 11 and th3, were incubated with linoleic acid, and the metabolites were isolated and identified by gc-ms and lc-ms. the two main metabolites were identified as 8-hydroxylinoleic and 7,8-dihydroxylinoleic acids, and the former was further oxidized by n-2 and by n-3 hydroxylation to 8,16- and 8,17-dihydroxylinoleic acids. lipoxygenase metabolites of linoleic acid could not be detected. the sequence of the genome of m. grisea has been released from ... | 2003 | 14870931 |
| an attempt to protect winter wheat against gaeumannomyces graminis var. tritici by the use of rhizobacteria pseudomonas fluorescens and bacillus mycoides. | pseudomonas fluorescens strains iii107 and ii21 and bacillus mycoides strains jc192 and k184, stimulating growth of winter wheat, were chosen for the studies. the bacterial strains inhibited on agar nutrient medium the growth of gaeumannomyces graminis var. tritici (ggt)--the pathogenic fungus causing take-all on wheat. both strains of pseudomonads synthesized relatively high amounts of fe3+ chelators. the strains of bacilli were characterized by the very fast spreading on agar media. furthermor ... | 2004 | 15478355 |
| melanin synthesis is associated with changes in hyphopodial turgor, permeability, and wall rigidity in gaeumannomyces graminis var. graminis. | mycelia of gaeumannomyces graminis var. graminis form large cells called hyphopodia with deeply lobed, melanized walls. like appressoria produced by other pathogens, hyphopodia develop on hydrophobic surfaces, but it is not clear that hyphopodia function as platforms for host penetration. in appressoria, melanin synthesis is linked to the generation of enormous turgor pressures that provide the necessary force for plant penetration. in the present study, hyphopodial turgor was measured in a wild ... | 1998 | 9742204 |
| analysis of novel hydroperoxides and other metabolites of oleic, linoleic, and linolenic acids by liquid chromatography-mass spectrometry with ion trap msn. | linoleate is oxygenated by manganese-lipoxygenase (mn-lo) to 11s-hydroperoxylinoleic acid and 13r-hydroperoxyoctadeca-9z,11e-dienoic acid, whereas linoleate diol synthase (lds) converts linoleate sequentially to 8r-hydroperoxylinoleate, through an 8-dioxygenase by insertion of molecular oxygen, and to 7s,8s-dihydroxylinoleate, through a hydroperoxide isomerase by intramolecular oxygen transfer. we have used liquid chromatography-mass spectrometry (lc-ms) with an ion trap mass spectrometer to stu ... | 1998 | 9778131 |
| purification and characterization of a secreted laccase of gaeumannomyces graminis var. tritici. | we purified a secreted fungal laccase from filtrates of gaeumannomyces graminis var. tritici cultures induced with copper and xylidine. the active protein had an apparent molecular mass of 190 kda and yielded subunits with molecular masses of 60 kda when denatured and deglycosylated. this laccase had a pi of 5.6 and an optimal ph of 4.5 with 2,6-dimethoxyphenol as its substrate. like other, previously purified laccases, this one contained several copper atoms in each subunit, as determined by in ... | 1999 | 10388705 |
| cloning of linoleate diol synthase reveals homology with prostaglandin h synthases. | linoleate diol synthase is a homotetrameric ferric hemeprotein, which catalyzes dioxygenation of linoleic acid to (8r)-hydroperoxylinoleate and isomerization of the hydroperoxide to (7s,8s)-dihydroxylinoleate. ferryl intermediates and a tyrosyl radical are formed in the reaction. linoleate diol synthase was digested with endoproteinase lys-c, and internal peptides were sequenced. the sequence information was used for reverse transcription-polymerase chain reaction analysis, and a cdna probe was ... | 1999 | 10497176 |
| catalytic properties of linoleate diol synthase of the fungus gaeumannomyces graminis: a comparison with pgh synthases. | | 1999 | 10667399 |
| the biosynthesis of oxylipins of linoleic and arachidonic acids by the sewage fungus leptomitus lacteus, including the identification of 8r-hydroxy-9z,12z-octadecadienoic acid. | when the sewage fungus leptomitus lacteus was grown in liquid culture aerobically and then transferred to medium containing long-chain fatty acids, it produced a number of oxygenated fatty acids. from linoleic acid (18:2n-6), the major metabolite produced was r-8-hydroxy-9z,12z-octadecadienoic acid (8r-hode), with additional quantities of 8,11-di-hode, 11,16-di-hode, and 11,17-di-hode. other fatty acid derivatives identified included 7-hode, 10-hode, and 13-hydroxy-octadecamonoenoic acid. arachi ... | 2000 | 10695920 |
| a group i intron in the nuclear small subunit ribosomal dna of gaeumannomyces graminis. | the length of the small subunit ribosomal dna (ssu rdna) differs among isolates of species and varieties of gaeumannomyces. the sequence of the 3' region of the ssu rdna revealed 340-, 365-, and 520-bp insertions for g. graminis varieties avenae, tritici, and graminis, respectively. the intron sequences from varities tritici and avenae were similar, except there was an insert of 23 nucleotides at base 328 from the 5' end of the g. g. var. tritici intron. the g. g. var. graminis intron sequences ... | 2000 | 10706657 |
| genetic diversity and biological control activity of novel species of closely related pseudomonads isolated from wheat field soils in south australia. | rhizobacteria closely related to two recently described species of pseudomonads, pseudomonas brassicacearum and pseudomonas thivervalensis, were isolated from two geographically distinct wheat field soils in south australia. isolation was undertaken by either selective plating or immunotrapping utilizing a polyclonal antibody raised against p. brassicacearum. a subset of 42 isolates were characterized by amplified 16s ribosomal dna restriction analysis (ardra), biolog analysis, and gas chromatog ... | 2000 | 10742249 |
| kinetics of manganese lipoxygenase with a catalytic mononuclear redox center. | manganese lipoxygenase was isolated from the take-all fungus, gaeumannomyces graminis, and the oxygenation mechanism was investigated. a kinetic isotope effect, k(h)/k(d) = 21-24, was observed with [u-(2)h]linoleic acid as a substrate. the relative biosynthesis of (11s)-hydroperoxylinoleate (11s-hpode) and (13r)-hydroperoxylinoleate (13r-hpode) was ph-dependent and changed by [u-(2)h]linoleic acid. stopped-flow kinetic traces of linoleic and alpha-linolenic acids indicated catalytic lag times of ... | 2000 | 10751400 |
| terpenoids and flavonoids from artemisia species. | a phytochemical reinvestigation of the aerial parts of artemisia sieversiana gave a new guaianolide and two known flavones (chrysosplenetin and 5-hydroxy-3',4',6,7-tetramethoxyflavone). antifungal fractions derived from the chloroform extract of a. annua afforded two cadinane derivatives (arteannuin b and artemisinin), oleanolic acid, beta-sitosterol, stigmasterol, and the four flavones artemetin, bonanzin, eupalitin and chrysosplenetin. their structures were elucidated by spectral methods. all ... | 2000 | 10865468 |
| stagonospora avenae secretes multiple enzymes that hydrolyze oat leaf saponins. | the phytopathogenic fungus stagonospora avenae is able to infect oat leaves despite the presence of avenacoside saponins in the leaf tissue. in response to pathogen attack, avenacosides are converted into 26-desglucoavenacosides (26-dgas), which possess antifungal activity. these molecules are comprised of a steroidal backbone linked to a branched sugar chain consisting of one alpha-l-rhamnose and two (avenacoside a) or three (avenacoside b) beta-d-glucose residues. isolates of the fungus that a ... | 2000 | 11043466 |
| effects of targeted replacement of the tomatinase gene on the interaction of septoria lycopersici with tomato plants. | many plants produce constitutive antifungal molecules belonging to the saponin family of secondary metabolites, which have been implicated in plant defense. successful pathogens of these plants must presumably have some means of combating the chemical defenses of their hosts. in the oat root pathogen gaeumannomyces graminis, the saponin-detoxifying enzyme avenacinase has been shown to be essential for pathogenicity. a number of other phytopathogenic fungi also produce saponin-degrading enzymes, ... | 2000 | 11106022 |
| antifungal activity of artemisia annua endophyte cultures against phytopathogenic fungi. | artemisia annua, well recognized for its production of antimalarial drug artemisinin, is seldom attacked by any of phytopathogenic fungi, which could be partially associated with the presence of endophytes. present investigation is aiming at disclosing whether the endophytes inside a. annua produce antifungal substances. a total of 39 endophytes were isolated and fermented, and the ferment broth was evaluated in vitro for the antifungal activity against crop-threatening fungi gaeumannomyces gram ... | 2001 | 11434973 |
| changes in populations of rhizosphere bacteria associated with take-all disease of wheat. | take-all, caused by gaeumannomyces graminis var. tritici, is one of the most important fungal diseases of wheat worldwide. knowing that microbe-based suppression of the disease occurs in monoculture wheat fields following severe outbreaks of take-all, we analyzed the changes in rhizosphere bacterial communities following infection by the take-all pathogen. several bacterial populations were more abundant on diseased plants than on healthy plants, as indicated by higher counts on a pseudomonas-se ... | 2001 | 11571137 |
| control of microorganisms in the rhizosphere of wheat by inoculation of seeds with pseudomonas putida and by foliar application of urea. | after inoculation of wheat seeds with various bacterial strains germination of plants was usually inhibited at first but growth was stimulated later. after inoculation with pseudomonas putida k 11 producing physiologically active compounds the total number of bacteria increased together with the bacteria: fungi ratio in the rhizosphere. these characteristic were further increased after foliar application of urea due to increased root exudation. dry mass of upper wheat parts was about 14--80% hig ... | 1981 | 7203287 |
| molecular mechanisms of defense by rhizobacteria against root disease. | genetic resistance in plants to root diseases is rare, and agriculture depends instead on practices such as crop rotation and soil fumigation to control these diseases. "induced suppression" is a natural phenomenon whereby a soil due to microbiological changes converts from conducive to suppressive to a soilborne pathogen during prolonged monoculture of the susceptible host. our studies have focused on the wheat root disease "take-all," caused by the fungus gaeumannomyces graminis var. tritici, ... | 1995 | 11607544 |
| the dark side of the mycelium: melanins of phytopathogenic fungi. | melanins are darkly pigmented polymers that protect organisms against environmental stress. even when not directly involved in pathogenesis, fungal melanin is likely required by melanizing phytopathogens for survival in the environment. however, some phytopathogenic fungi that produce melanized appressoria for host invasion require appressorial melanogenesis for pathogenicity. much less is known about the role melanins play in pathogenesis during infection by other phytopathogens that do not rel ... | 1999 | 11701831 |
| cloning of the manganese lipoxygenase gene reveals homology with the lipoxygenase gene family. | manganese lipoxygenase was isolated to homogeneity from the take-all fungus, gaeumannomyces graminis. the c-terminal amino acids and several internal peptides were sequenced, and the information was used to obtain a cdna probe by rt/pcr. screening of a genomic library of g. graminis yielded a full-length clone of the mn-lipoxygenase gene. cdna analysis showed that the gene spanned 2.6 kb and contained one intron (133 bp). northern blot analyses indicated two transcripts (2.7 and 3.1 kb). the ded ... | 2002 | 12047377 |
| fungal pathogens of oat roots and tomato leaves employ closely related enzymes to detoxify different host plant saponins. | antifungal saponins are produced by many plants and have been implicated as preformed determinants of resistance to fungal attack. the importance of saponin detoxification in fungal pathogenesis has recently been demonstrated for the fungus gaeumannomyces graminis var. avenae, which produces the enzyme avenacinase. avenacinase detoxifies the triterpenoid oat root saponin avenacin a-1, and is essential for pathogenicity of g. graminis var.avenae to oats. here we demonstrate an unexpected relatedn ... | 1995 | 8664505 |
| antimicrobial activity of extracts of chemical races of the lichen pseudevernia furfuracea and their physodic acid, chloroatranorin, atranorin, and olivetoric acid constituents. | the antimicrobial activity and the mic values of the ethanol, chloroform, diethyl ether, and acetone extracts of the chemical races of pseudevernia furfuracea (var. furfuracea and var. ceratea) and their physodic acid, chloroatranorin, atranorin, and olivetoric acid constituents have been investigated against some microorganisms. nearly all extracts of both chemical races showed antimicrobial activity against aeromonas hydrophila, bacillus cereus, bacillus subtilis, listeria monocytogenes, prote ... | 2006 | 16989308 |
| origin and inheritance of group i introns in 26s rrna genes of gaeumannomyces graminis. | studies of the distribution of the three group i introns (intron a, intron t, and intron at) in the 26s rdna of gaeumannomyces graminis had suggested that they were transferred to a common ancestor of g. graminis var. avenae and var. tritici after it had branched off from var. graminis. intron at and intron a exhibited vertical inheritance and coevolved in concert with their hosts. intron loss could occur after its acquisition. loss of any one of the three introns could occur in var. tritici whe ... | 1997 | 9169556 |
| n-acyl-homoserine lactone-mediated regulation of phenazine gene expression by pseudomonas aureofaciens 30-84 in the wheat rhizosphere. | pseudomonas aureofaciens 30-84 is a soilborne bacterium that colonizes the wheat rhizosphere. this strain produces three phenazine antibiotics which suppress take-all disease of wheat by inhibition of the causative agent gaeumannomyces graminis var. tritici. phenazines also enhance survival of 30-84 within the wheat rhizosphere in competition with other organisms. expression of the phenazine biosynthetic operon is controlled by the phzr/phzi n-acyl-homoserine lactone (ahl) response system (l. s. ... | 1997 | 9401023 |
| characterization of a split respiratory pathway in the wheat "take-all" fungus, gaeumannomyces graminis var. tritici. | this article describes the first detailed analysis of mitochondrial electron transfer and oxidative phosphorylation in the pathogenic filamentous fungus, gaeumannomyces graminis var. tritici. while oxygen consumption was cyanide insensitive, inhibition occurred following treatment with complex iii inhibitors and the alternative oxidase inhibitor, salicylhydroxamic acid (sham). similarly, maintenance of a deltapsi across the mitochondrial inner membrane was unaffected by cyanide but sensitive to ... | 1998 | 9556599 |
| identification and manipulation of soil properties to improve the biological control performance of phenazine-producing pseudomonas fluorescens. | pseudomonas fluorescens 2-79rn(10) protects wheat against take-all disease caused by gaeumannomyces graminis var. tritici; however, the level of protection in the field varies from site to site. identification of soil factors that exert the greatest influence on disease suppression is essential to improving biocontrol. in order to assess the relative importance of 28 soil properties on take-all suppression, seeds were treated with strain 2-79rn(10) (which produces phenazine-1-carboxylate [pca(+) ... | 2003 | 12788734 |
| changes in population structure of the soilborne fungus gaeumannomyces graminis var. tritici during continuous wheat cropping. | a method was developed to assess the genetic structure of gaeumannomyces graminis var. tritici (ggt) populations and test the hypothesis of an association between disease level in the field with changes in pathogen populations. a long-term wheat monoculture experiment, established since 1994, generated different take-all epidemics with varying the number of wheat crop successions in the 1999-2000 cropping season. genetic polymorphism in ggt populations was investigated over natural, local epidem ... | 2004 | 15479250 |
| effect of mixed and single crops on disease suppressiveness of soils. | abstract the effect of mixed cropping on disease suppressiveness of soils was tested for two cropping systems, brussels sprouts-barley and triticale-white clover. disease suppressiveness of field soils was evaluated in bioassays for the soilborne pathogens rhizoctonia solani, fusarium oxysporum f. sp. lini, and gaeumannomyces graminis var. tritici. for both cropping systems, mixed cropping did not enhance disease suppressiveness of the soils. in some cases, soil cropped to barley alone was signi ... | 2005 | 18943364 |
| apoplastic extracts from a transgenic wheat line exhibiting lesion-mimic phenotype have multiple pathogenesis-related proteins that are antifungal. | a transgenic wheat line constitutively expressing genes encoding a class iv acidic chitinase and an acidic beta-1,3-glucanase, showed significant delay in spread of fusarium head blight (scab) disease under greenhouse conditions. in an earlier work, we observed a lesion-mimic phenotype in this transgenic line when homozygous for transgene loci. apoplastic fluid (af) extracted from the lesion-mimic plants had pathogenesis-related (pr) proteins belonging to families of beta-1,3-glucanases, chitina ... | 2004 | 15597736 |
| expression of manganese lipoxygenase in pichia pastoris and site-directed mutagenesis of putative metal ligands. | manganese lipoxygenase is secreted by the fungus gaeumannomyces graminis. we expressed the enzyme in pichia pastoris, which secreted approximately 30 mg mn-lipoxygenase/l culture medium in fermentor. the recombinant lipoxygenase was n- and o-glycosylated (80-100 kda), contained approximately 1 mol mn/mol protein, and had similar kinetic properties (k(m) approximately 7.1 microm alpha-linolenic acid and v(max) 18 nmol/min/microg) as the native mn-lipoxygenase. mn-lipoxygenase could be quantitativ ... | 2005 | 15629124 |
| [cloning and functional characterization of the gacs gene of the biocontrol strain pseudomonas fluorescens 2p24]. | pseudomonas fluorescens 2p24, a biocontrol agent for soil-borne diseases has been isolated from the wheat take-all decline soil, and was characterized with efficient production of antifungal compounds. in this study, the gacs gene was cloned by pcr from the p. fluorescens 2p24 genomic library. nucleotide sequencing indicated that the gacs gene contains 2754 bp, and is predicted to encode a peptide of 917 amino acids with molecular mass of 101 kd. the deduced amino acid sequence shares 91% identi ... | 2005 | 15989228 |
| isolation and characterization of linear dna elements from the mitochondria of gaeumannomyces graminis. | different gaeumannomyces graminis strains of diverse geographic origin contain one or two small dnas ranging in size from 7.2 to 10 kilobases. these dnas exhibit different degrees of homology with each other. we have characterized these low-molecular-weight dnas from one strain, ha-01. these small dnas, e1 and e2, are mitochondrial in origin and were isolated as linear molecules which exhibited an intrinsic difference in density from the high-molecular-weight dna. | 1986 | 16347184 |
| dna probe for identification of the take-all fungus, gaeumannomyces graminis. | a 4.3-kilobase mitochondrial dna fragment was cloned from gaeumannomyces graminis var. tritici, the causative agent of take-all disease of wheat. although this dna fragment hybridized with all three varieties of g. graminis, it showed little homology with dna from other fungi and thus should be useful for identification of gaeumannomyces sp. recovered from infected plants. | 1989 | 16347842 |
| production of the antibiotic phenazine-1-carboxylic acid by fluorescent pseudomonas species in the rhizosphere of wheat. | pseudomonas fluorescens 2-79 and p. aureofaciens 30-84 produce the antibiotic phenazine-1-carboxylic acid and suppress take-all, an important root disease of wheat caused by gaeumannomyces graminis var. tritici. to determine whether the antibiotic is produced in situ, wheat seeds were treated with strain 2-79 or 30-84 or with phenazine-nonproducing mutants or were left untreated and then were sown in natural or steamed soil in the field or growth chamber. the antibiotic was isolated only from ro ... | 1990 | 16348176 |
| use of polymerase chain reaction to detect the take-all fungus, gaeumannomyces graminis, in infected wheat plants. | gaeumannomyces graminis, the causative agent of take-all disease of wheat, barley, and oats, was detected in infected wheat seedlings by using the polymerase chain reaction to amplify gaeumannomyces-specific dna fragments. nested primers and two rounds of amplification were used to amplify two fragments, approximately 287 and 188 bp in size, from g. graminis-infected wheat seedlings. the use of nested primers greatly decreased the number of nonspecific amplification products. polymerase chain re ... | 1991 | 16348420 |
| influence of crop management on take-all development and disease cycles on winter wheat. | abstract wheat was assessed at four crop growth stages for take-all (gaeumannomyces graminis var. tritici) in a series of field trials that studied the effects of five wheat management practices: sowing date, plant density, nitrogen fertilizer dose and form, and removal/burial of cereal straw. an equation expressing disease level as a function of degree days was fitted to the observed disease levels. this equation was based on take-all epidemiology and depended on two parameters reflecting the i ... | 1997 | 18945150 |
| effects of fungal root pathogens on the population dynamics of biocontrol strains of fluorescent pseudomonads in the wheat rhizosphere. | the influences of gaeumannomyces graminis var. tritici (which causes take-all of wheat), rhizoctonia solani ag-8 (which causes rhizoctonia root rot of wheat), pythium irregulare, p. aristosporum, and p. ultimum var. sporangiiferum (which cause pythium root rot of wheat) on the population dynamics of pseudomonas fluorescens 2-79 and q72a-80 (bicontrol strains active against take-all and pythium root rot of wheat, respectively) in the wheat rhizosphere were examined. root infection by either g. gr ... | 1991 | 16348532 |
| gluconic acid: an antifungal agent produced by pseudomonas species in biological control of take-all. | pseudomonas strain an5 (ps. str. an5), a non-fluorescent australian bacterial isolate, is an effective biological control (biocontrol) agent of the take-all disease of wheat caused by the fungus gaeumannomyces graminis var. tritici (ggt). ps. str. an5 controls ggt by producing an antifungal compound which was purified by thin layer and column chromatography, and identified by nmr and mass spectroscopic analysis to be d-gluconic acid. commercially bought pure gluconic acid strongly inhibited ggt. ... | 2006 | 16445952 |
| survival, growth and pathogenicity of gaeumannomyces graminis var. graminis with different methods of long-term storage. | the fungal plant pathogen gaeumannomyces graminis var. graminis was preserved with 12 different storage methods. five strains, each with unique morphological and pathological characteristics, were used for comparison of the methods. the storage treatments included potato-dextrose agar slants, with or without mineral oil, stored at either 4 c, 28 c or ambient temperature; colonized agar plugs placed in glycerol solution at either -75 c or -20 c; colonized agar plugs placed in sterile deionized wa ... | 2005 | 16457359 |
| effects of some benzoxazinoids on in vitro growth of cephalosporium gramineum and other fungi pathogenic to cereals and on cephalosporium stripe of winter wheat. | the benzoxazolinones benzoxazolin-2(3h)-one (boa) and 6-methoxybenzoxazolin-2(3h)-one (mboa) and selected degradation products of these compounds were examined for their in vitro antifungal activity against cephalosporium gramineum, gaeumannomyces graminis var. graminis, and fusarium culmorum. boa was also applied to the soil-incorporated inoculum of c. gramineum to test its capability of reducing cephalosporium stripe disease in winter wheat. mboa reduced the mycelial growth of g. graminis var. ... | 2006 | 16478214 |
| the role of dsba in colonization of the wheat rhizosphere by pseudomonas fluorescens q8r1-96. | certain well-conserved genes in fluorescent pseudomonas spp. are involved in pathogenic interactions between the bacteria and evolutionarily diverse hosts including plants, insects and vertebrate animals. one such gene, dsba, encodes a periplasmic disulfide-bond-forming enzyme implicated in the biogenesis of exported proteins and cell surface structures. this study focused on the role of dsba in pseudomonas fluorescens q8r1-96, a biological control strain that produces the antibiotic 2,4-diacety ... | 2006 | 16514165 |
| melanin production by a filamentous soil fungus in response to copper and localization of copper sulfide by sulfide-silver staining. | gaeumannomyces graminis var. graminis, a filamentous soil ascomycete, exhibited enhanced cell wall melanin accumulation when exposed to as little as 0.01 mm cuso(inf4) in minimal broth culture. because its synthesis was inhibited by tricyclazole, the melanin produced in response to copper was dihydroxynaphthalene melanin. an additional hyphal cell wall layer was visualized by electron microscopy when hyphae were grown in the presence of copper and fixed by cryotechniques. this electron-dense lay ... | 1995 | 16535031 |
| variation in sensitivity of gaeumannomyces graminis to antibiotics produced by fluorescent pseudomonas spp. and effect on biological control of take-all of wheat. | isolates of gaeumannomyces graminis var. tritici, the causal agent of take-all of wheat, varied in sensitivity in vitro to the antibiotics phenazine-1-carboxylic acid (pca) and 2,4-diacetylphloroglucinol (phl) produced by fluorescent pseudomonas spp. shown previously to have potential for biological control of this pathogen. none of the four isolates of g. graminis var. avenae examined were sensitive to either of the antibiotics in vitro at the concentrations tested. the single isolate of g. gra ... | 1995 | 16535070 |
| [endophytic bacteria isolated from wheat and their antifungal activities to soil-borne disease pathogens]. | in this paper, endophytic bacteria (eb) were isolated from the roots, stems, leaves and immature seeds of wheat at its different growth stages. the eb populations in fresh wheat tissues reached 5.0 x 10(5) cfu x g(-1) on average, with a significant difference among different tissues, growth stages and fields. the eb count was 7.8 x 10(5) in wheat roots, 4.8 x 10(5) in stems, 3.2 x 10(5) in leaves, and 2.8 x 10(5) cfu x g(-1) in immature seeds, and was estimated as 3.1 x 10(5), 5.7 x 10(5) and 7. ... | 2006 | 16836103 |
| major secondary metabolites produced by two commercial trichoderma strains active against different phytopathogens. | trichoderma harzianum strains t22 and t39 are two micro-organisms used as active agents in a variety of commercial biopesticides and biofertilizers and widely applied amongst field and greenhouse crops. the production, isolation, biological and chemical characterization of the main secondary metabolites produced by these strains are investigated. | 2006 | 16869896 |
| role of ptsp, orft, and sss recombinase genes in root colonization by pseudomonas fluorescens q8r1-96. | pseudomonas fluorescens q8r1-96 produces 2,4-diacetylphloroglucinol (2,4-dapg), a polyketide antibiotic that suppresses a wide variety of soilborne fungal pathogens, including gaeumannomyces graminis var. tritici, which causes take-all disease of wheat. strain q8r1-96 is representative of the d-genotype of 2,4-dapg producers, which are exceptional because of their ability to aggressively colonize and maintain large populations on the roots of host plants, including wheat, pea, and sugar beet. in ... | 2006 | 16936061 |
| role of 2,4-diacetylphloroglucinol-producing fluorescent pseudomonas spp. in the defense of plant roots. | plants have evolved strategies of stimulating and supporting specific groups of antagonistic microorganisms in the rhizosphere as a defense against diseases caused by soilborne plant pathogens owing to a lack of genetic resistance to some of the most common and widespread soilborne pathogens. some of the best examples of natural microbial defense of plant roots occur in disease suppressive soils. soil suppressiveness against many different diseases has been described. take-all is an important ro ... | 2007 | 17058178 |
| mechanisms of natural soil suppressiveness to soilborne diseases. | suppressive soils are characterized by a very low level of disease development even though a virulent pathogen and susceptible host are present. biotic and abiotic elements of the soil environment contribute to suppressiveness, however most defined systems have identified biological elements as primary factors in disease suppression. many soils possess similarities with regard to microorganisms involved in disease suppression, while other attributes are unique to specific pathogen-suppressive so ... | 2002 | 12448751 |
| linear relationship between gaeumannomyces graminis var. tritici (ggt) genotypic frequencies and disease severity on wheat roots in the field. | in order to investigate potential links existing between gaeumannomyces graminis var. tritici (ggt) population structure and disease development during polyetic take-all epidemics in sequences of ggt host cereals, seven epidemics in fields with different cropping histories were monitored during the seasons 2001/2002 (two fields), 2002/2003 (two fields) and 2003/2004 (three fields). take-all incidence and severity were measured at stem elongation and ggt populations were characterized. the 73 iso ... | 2007 | 17222147 |
| [the production of phenazine antibiotics by the pseudomonas aureofaciens strain with plasmid-controlled resistance to cobalt and nickel]. | plasmid pbs501 responsible for the resistance of the wild-type pseudomonas sp. bs501 (pbs501) to cobalt and nickel ions was conjugatively transferred to the rhizosphere pseudomonas aureofaciens strain bs1393, which is able to synthesize phenazine antibiotics and to suppress a wide range of phytopathogenic microorganisms. the transconjugant p. aureofaciens bs1393 (pbs501) turned out to be resistant to cobalt and nickel with an mic of 8 mm. when grown in a synthetic medium with 0.25 mm cobalt, the ... | 2002 | 12526199 |
| colonization of barley roots by endophytic fungi and their reduction of take-all caused by gaeumannomyces graminis var. tritici. | fungal root endophytes obtained from natural vegetation were tested for antifungal activity in dual culture tests against the root pathogen gaeumannomyces graminis var. tritici. fifteen isolates, including acremonium blochii, acremonium furcatum, aspergillus fumigatus, cylindrocarpon sp., cylindrocarpon destructans, dactylaria sp., fusarium equiseti, phoma herbarum, phoma leveillei, and a sterile mycelium, selected based on the dual culture test, were inoculated on barley roots in growth tubes u ... | 2008 | 18772922 |
| evidence of a multicopper oxidase in mn oxidation by gaeumannomyces graminis var. tritici. | abstract manganese (mn) oxidation by the plant-pathogenic fungus gaeumannomyces graminis var. tritici has been correlated with virulence in take-all disease. the mechanism of mn oxidation has not, however, been investigated adequately. research on bacteria and other fungi indicates that mn oxidation is most often the result of the activity of multicopper oxidases. to determine if g. graminis var. tritici oxidizes mn by similar means, the mn oxidizing factor (mof) produced by g. graminis var. tri ... | 2006 | 18943915 |
| genetic diversity of phld from 2,4-diacetylphloroglucinol-producing fluorescent pseudomonas spp. | abstract fluorescent pseudomonas spp. that produce 2,4-diacetylphloroglucinol (2,4-dapg) have biocontrol activity against damping-off, root rot, and wilt diseases caused by soilborne fungal pathogens, and play a key role in the natural suppression of gaeumannomyces graminis var. tritici, known as take-all decline. diversity within phld, an essential gene in the biosynthesis of 2,4-dapg, was studied by restriction fragment length polymorphism (rflp) analysis of 123 2,4-dapg-producing isolates fro ... | 2001 | 18944276 |
| an epidemiological analysis of the role of disease-induced root growth in the differential response of two cultivars of winter wheat to infection by gaeumannomyces graminis var. tritici. | abstract epidemiological modeling combined with parameter estimation of experimental data was used to examine differences in the contribution of disease-induced root production to the spread of take-all on plants of two representative yet contrasting cultivars of winter wheat, ghengis and savannah. a mechanistic model, including terms for primary infection, secondary infection, inoculum decay, and intrinsic and disease-induced root growth, was fitted to data describing changes in the numbers of ... | 2006 | 18944311 |
| modeling of take-all epidemics to evaluate the efficacy of a new seed-treatment fungicide on wheat. | abstract take-all, caused by gaeumannomyces graminis var. tritici, is a damaging disease of wheat that remains difficult to control. the efficacy of an experimental fungicide, applied as a seed treatment, was evaluated in five naturally infested field experiments conducted during three cropping seasons. plants were sampled and assessed for take-all incidence and severity at different growth stages. nonlinear models expressing disease variables as a function of degree-days were fitted to the obse ... | 1999 | 18944741 |
| dynamics of primary and secondary infection in take-all epidemics. | abstract using a combination of experimentation and mathematical modeling, the effects of initial (particulate) inoculum density on the dynamics of disease resulting from primary and secondary infection of wheat by the take-all fungus, gaeumannomyces graminis var. tritici, were tested. a relatively high inoculum density generated a disease progress curve that rose monotonically toward an asymptote. reducing the initial inoculum density resulted in a curve that initially was monotonic, rising to ... | 1999 | 18944808 |
| bacillus sp. l324-92 for biological control of three root diseases of wheat grown with reduced tillage. | abstract strain l324-92 is a novel bacillus sp. with biological activity against three root diseases of wheat, namely take-all caused by gaeumannomyces graminis var. tritici, rhizoctonia root rot caused by rhizoctonia solani ag8, and pythium root rot caused mainly by pythium irregulare and p. ultimum, that exhibits broad-spectrum inhibitory activity and grows at temperatures from 4 to 40 degrees c. these three root diseases are major yieldlimiting factors for wheat in the u.s. inland pacific nor ... | 1997 | 18945111 |
| population dynamics of bacillus sp. l324-92r(12) and pseudomonas fluorescens 2-79rn(10) in the rhizosphere of wheat. | abstract bacillus sp. l324-92 is suppressive to three root diseases of wheat, namely take-all caused by gaeumannomyces graminis var. tritici, rhizoctonia root rot caused by rhizoctonia solani ag8, and pythium root rot caused by several pythium species. populations of strain l324-92r(12), a rifampicin-resistant mutant of l324-92 applied as a seed treatment, were monitored in the rhizosphere and spermosphere of wheat and compared with populations of pseudomonas fluorescens 2-79rn(10), a known, rhi ... | 1997 | 18945112 |
| production and characterization of a monoclonal antibody raised against surface antigens from mycelium of gaeumannomyces graminis var. tritici: evidence for an extracellular polyphenol oxidase. | abstract a murine monoclonal antibody (mab) of immunoglobulin class m (igm) was raised against surface antigens from gaeumannomyces graminis var. tritici and, by enzyme-linked immunosorbent assay, recognized isolates of g. graminis var. tritici, g. graminis var. avenae and g. graminis var. graminis. characterization of the antigen by heat and protease treatments showed that the epitope recognized by the mab was a protein. antigen production was detected only in live mycelia. immunofluorescence s ... | 1997 | 18945163 |
| Enhancing plant disease suppression by Burkholderia vietnamiensis through chromosomal integration of Bacillus subtilis chitinase gene chi113. | Burkholderia vietnamiensis P418 is a plant growth-promoting rhizobacteria. A chitinase gene from Bacillus subtilis was cloned and stably integrated into the chromosome of using the transposon delivery vector, pUTkm1. Chitinase activity was detected in recombinant P418-37 but not in wild type P418. Recombinant P418-37 retained the in vitro growth rate, N(2)-fixation and phosphate and potassium-solubilizing characteristics of the wild type. P418-37 significantly (P < 0.05) inc ... | 2011 | 21972146 |
| effect of mycorrhizal fungi on some defense enzymes against gaeumannomyces gaminis in wheat. | at this research, the effect of mycorrhizal fungi (glomus etunicatum) on pero xidase (pox) and phenylalanine ammonia lyase (pal) activities and isozymatic pattern against gaeumannomyces graminis were studied in wheat plants. seeds were planted in inoculated soils in 4 treatment groups including control (c), mycorrhiza (m), pathogen (p) and pathogen- mycorrhiza (pm). plants were harvested 17 days after inoculation. pox activities in pm group were significantly greater than control group. signific ... | 2007 | 19070167 |
| influence of glyphosate, crop volunteer and root pathogens on glyphosate-resistant wheat under controlled environmental conditions. | the herbicide glyphosate has a synergistic effect on root disease because of increased susceptibility from reduced plant defenses resulting from the blockage of the shikimic acid pathway. could glyphosate-resistant (gr) wheat cultivars and glyphosate application in-crop increase the risk of damage from soil-borne pathogens? growth chamber experiments were conducted with two gr wheat lines and their corresponding glyphosate-sensitive (gs) parents and four pathogens (rhizoctonia solani kühn r. ory ... | 2009 | 19115241 |
| the plant pathogenic fungus gaeumannomyces graminis var. tritici improves bacterial growth and triggers early gene regulations in the biocontrol strain pseudomonas fluorescens pf29arp. | in soil, some antagonistic rhizobacteria contribute to reduce root diseases caused by phytopathogenic fungi. direct modes of action of these bacteria have been largely explored; however, commensal interaction also takes place between these microorganisms and little is known about the influence of filamentous fungi on bacteria. an in vitro confrontation bioassay between the pathogenic fungus gaeumannomyces graminis var. tritici (ggt) and the biocontrol bacterial strain pseudomonas fluorescens pf2 ... | 2009 | 19121038 |
| feeding of the nematode acrobeloides nanus on bacteria. | information on the effect of bacteria-feeding nematodes on bacterial populations in the soil is sparse. we have isolated, cultured, and microscopically examined bacteria and nematodes coexisting within an agricultural soil and have studied their feeding relationship. the bacterium pseudomonas corrugata isolate 2140r is a biocontrol agent against the pathogenic fungus gaeumannomyces graminis var. tritici. the nematode acrobeloides nanus is a cosmopolitan, bacteria-feeding organism widespread in a ... | 1993 | 19279801 |
| influence of some environmental factors on populations of pratylenchus minyus in wheat. | the distribution and density of pratylenchus minyus and possible relationships of several environmental components, including ammonium nitrate, were investigated in a wheat field in south australia. seasonal variation as measured every 2-4 weeks was eliminated from the observations by periodic regression. correlation and regression analyses were then used to investigate the association of host plant, rainfall, temperature, and the fungus gaeumannomyces graminis with p. minyus. other than seasona ... | 1976 | 19308238 |