| ultrastructural study of galacturonic acid distribution in some pathogenic fungi using gold-complexed aplysia depilans gonad lectin. | aplysia gonad lectin, isolated from the mollusc aplysia depilans, was successfully conjugated to colloidal gold and used for ultrastructural detection of galacturonic acids in some pathogenic fungi. these sugar residues were found to occur in the fibrillar sheath surrounding hyphal cells of ascocalyx abietina and in intravacuolar dense inclusions of this fungus spores. in hyphae and spores of ophiostoma ulmi, galacturonic acids were detected mainly in the outermost wall layers. in contrast, thes ... | 1989 | 2659155 |
| physiological and biochemical characterization of trichoderma harzianum, a biological control agent against soilborne fungal plant pathogens. | monoconidial cultures of 15 isolates of trichoderma harzianum were characterized on the basis of 82 morphological, physiological, and biochemical features and 99 isoenzyme bands from seven enzyme systems. the results were subjected to numerical analysis which revealed four distinct groups. representative sequences of the internal transcribed spacer 1 (its 1)-its 2 region in the ribosomal dna gene cluster were compared between groups confirming this distribution. the utility of the groupings gene ... | 1997 | 9251205 |
| the effect of different pectic growth substrates on beta-glucosidase in fusarium oxysporum f. sp. radicis lycopersici: partial purification and characterization. | fusarium oxysporum f. sp. radicis lycopersici produces beta-glucosidase activities when it grows on pectin and glucose. the pectins were better substrates than glucose. in the medium containing galacturonic acid or sucrose the activity was present in low levels and at the end of autolysis. a beta-glucosidase from the pectin medium was purified by ion exchange chromatography followed by gel filtration. the enzyme was a unique band of protein in sds-page and isoelectric focussing. it had a molecul ... | 1997 | 9258944 |
| control of polygalacturonase synthesis in fusarium oxysporum f.sp. radicis lycopersici. | genetic control of polygalacturonase (pg) activity from fusarium oxysporum f.sp. radicis lycopersici was analyzed on pectin and glucose cultures. one exopolygalacturonase from f. oxysporum f.sp. radicis lycopersici was strongly induced, in stationary culture, when the fungus was grown on apple pectin, while on glucose no extracellular pg activity could be detected. although sds-page detected the presence of a putative pg band (66 kda) in both conditions, specific antibodies obtained against the ... | 1997 | 9436311 |
| the course of pectin degradation by polygalacturonases from fusarium oxysporum f. sp. radicis lycopersici. | the production of polygalacturonases from fusarium oxysporum f. sp. radicis lycopersici (forl) occurred sequentially, and endo- and exo-polygalacturonases (pg) predominated at different times during growth. at first forl produced a pg which did not release monomers from pectins and was unable to hydrolyse dimers and trimers. later a complex was produced in which exo-pg seemed to be the predominant activity; the monomer was released rapidly and this activity was able to degrade dimers and trimers ... | 1997 | 9467919 |
| benzothiadiazole-mediated induced resistance to fusarium oxysporum f. sp. radicis-lycopersici in tomato | benzo-(1,2,3)-thiadiazole-7-carbothioic acid s-methyl ester (bth), a synthetic chemical, was applied as a foliar spray to tomato (lycopersicon esculentum) plants and evaluated for its potential to confer increased resistance against the soil-borne pathogen fusarium oxysporum f. sp. radicis-lycopersici (forl). in nontreated tomato plants all root tissues were massively colonized by forl hyphae. pathogen ingress toward the vascular stele was accompanied by severe host cell alterations, including c ... | 1998 | 9847094 |
| the sss colonization gene of the tomato-fusarium oxysporum f. sp. radicis-lycopersici biocontrol strain pseudomonas fluorescens wcs365 can improve root colonization of other wild-type pseudomonas spp.bacteria. | we show that the disease tomato foot and root rot caused by the pathogenic fungus fusarium oxysporum f. sp. radicis-lycopersici can be controlled by inoculation of seeds with cells of the efficient root colonizer pseudomonas fluorescens wcs365, indicating that strain wcs365 is a biocontrol strain. the mechanism for disease suppression most likely is induced systemic resistance. p. fluorescens strain wcs365 and p. chlororaphis strain pcl1391, which acts through the production of the antibiotic ph ... | 2000 | 11059484 |
| introduction of the phzh gene of pseudomonas chlororaphis pcl1391 extends the range of biocontrol ability of phenazine-1-carboxylic acid-producing pseudomonas spp. strains. | pseudomonas chlororaphis pcl1391 controls tomato foot and root rot caused by fusarium oxysporum f. sp. radicis-lycopersici. its biocontrol activity is mediated by the production of phenazine-1-carboxamide (pcn). in contrast, the take-all biocontrol strains p. fluorescens 2-79 and p. aureofaciens 30-84, which produce phenazine-1-carboxylic acid (pca), do not control this disease. to determine the role of the amide group in biocontrol, the pcn biosynthetic genes of strain pcl1391 were identified a ... | 2001 | 11497461 |
| phenazine-1-carboxamide production in the biocontrol strain pseudomonas chlororaphis pcl1391 is regulated by multiple factors secreted into the growth medium. | pseudomonas chlororaphis pcl1391 controls tomato foot and root rot caused by fusarium oxysporum f. sp. radicis-lycopersici. the production of phenazine-1-carboxamide (pcn) is crucial for this biocontrol activity. in vitro production of pcn is observed only at high-population densities, suggesting that production is under the regulation of quorum sensing. the main autoinducer molecule produced by pcl1391 was identified structurally as n-hexanoyl-l-homoserine lactone (c6-hsl). the two other autoin ... | 2001 | 11497469 |
| novel aspects of tomato root colonization and infection by fusarium oxysporum f. sp. radicis-lycopersici revealed by confocal laser scanning microscopic analysis using the green fluorescent protein as a marker. | the fungus fusarium oxysporum f. sp. radicis-lycopersici is the causal agent of tomato foot and root rot disease. the green fluorescent protein (gfp) was used to mark this fungus in order to visualize and analyze the colonization and infection processes in vivo. transformation of f oxysporum f. sp. radicis-lycopersici was very efficient and gfp expression was stable for at least nine subcultures. microscopic analysis of the transformants revealed homogeneity of the fluorescent signal, which was ... | 2002 | 11878320 |
| characterization and in vitro expression patterns of an exopolygalacturonase encoding gene from fusarium oxysporum f.sp. radicis lycopersici. | in this work, we report the isolation, characterization and expression pattern in in vitro cultures of an exopg encoding gene (pgx2), a novel exopg encoding gene of fusarium oxysporum f.sp. radicis lycopersici, responsible for foot crown and root rot disease in tomato plants. the gene was compared with other fungal polygalacturonases (pgs) previously reported. | 2003 | 12694451 |
| phylogeny of hcn synthase-encoding hcnbc genes in biocontrol fluorescent pseudomonads and its relationship with host plant species and hcn synthesis ability. | hydrogen cyanide (hcn) is a broad-spectrum antimicrobial compound involved in biological control of root diseases by many plant-associated fluorescent pseudomonads. the hcn synthase is encoded by three biosynthetic genes (hcna, hcnb, and hcnc), but little is known about the diversity of these genes in fluorescent pseudomonas spp. and in other bacteria. here, the partial hcnbc sequence was determined for a worldwide collection of biocontrol fluorescent pseudomonas spp. phylogenies based on hcnbc ... | 2003 | 12795378 |
| gacs sensor domains pertinent to the regulation of exoproduct formation and to the biocontrol potential of pseudomonas fluorescens cha0. | in the root-colonizing biocontrol strain cha0 of pseudomonas fluorescens, cell density-dependent synthesis of extracellular, plant-beneficial secondary metabolites and enzymes is positively regulated by the gacs/gaca two-component system. mutational analysis of the gacs sensor kinase using improved single-copy vectors showed that inactivation of each of the three conserved phosphate acceptor sites caused an exoproduct null phenotype (gacs-), whereas deletion of the periplasmic loop domain had no ... | 2003 | 12848429 |
| interactions in the tomato rhizosphere of two pseudomonas biocontrol strains with the phytopathogenic fungus fusarium oxysporum f. sp. radicis-lycopersici. | the fungus fusarium oxysporum f. sp. radicis-lycopersici causes foot and root rot of tomato plants, which can be controlled by the bacteria pseudomonas fluorescens wcs365 and p. chlororaphis pcl1391. induced systemic resistance is thought to be involved in biocontrol by p. fluorescens wcs365. the antifungal metabolite phenazine-1-carboxamide (pcn), as well as efficient root colonization, are essential in the mechanism of biocontrol by p. chlororaphis pcl1391. to understand the effects of bacteri ... | 2003 | 14601666 |
| potential role of pathogen signaling in multitrophic plant-microbe interactions involved in disease protection. | multitrophic interactions mediate the ability of fungal pathogens to cause plant disease and the ability of bacterial antagonists to suppress disease. antibiotic production by antagonists, which contributes to disease suppression, is known to be modulated by abiotic and host plant environmental conditions. here, we demonstrate that a pathogen metabolite functions as a negative signal for bacterial antibiotic biosynthesis, which can determine the relative importance of biological control mechanis ... | 2004 | 15006813 |
| high-nitrogen compost as a medium for organic container-grown crops. | compost was tested as a medium for organic container-grown crops. nitrogen (n) loss during composting of separated cow manure (scm) was minimized using high c/n (wheat straw, ws; grape marc, gm) or a slightly acidic (orange peels, op) additives. n conservation values in the resultant composts were 82%, 95% and 98% for gm-scm, op-scm and ws-scm, respectively. physical characteristics of the composts were compatible with use as growing media. the nutritional contribution of the composts was assess ... | 2005 | 15491822 |
| disease suppression on greenhouse tomatoes using plant waste compost. | this study investigated the disease suppression abilities of a compost amendment that was added to the conventional growing medium, yellow cedar sawdust, used in most british columbia vegetable greenhouses. the compost amendment was produced in a controlled, in-vessel process primarily from greenhouse crop waste materials. the pathogen and cultivar under study were fusarium oxysporum f. sp. radicis-lycopersici (forl) on dombito (forl-susceptible) beefsteak greenhouse tomatoes. significant reduct ... | 2005 | 15913017 |
| visualization of interactions between a pathogenic and a beneficial fusarium strain during biocontrol of tomato foot and root rot. | the soilborne fungus fusarium oxysporum f. sp. radicis-lycopersici causes tomato foot and root rot (tfrr), which can be controlled by the addition of the nonpathogenic fungus f. oxysporum fo47 to the soil. to improve our understanding of the interactions between the two fusarium strains on tomato roots during biocontrol, the fungi were labeled using different autofluorescent proteins as markers and subsequently visualized using confocal laser scanning microscopy. the results were as follows. i) ... | 2005 | 16042017 |
| enrichment for enhanced competitive plant root tip colonizers selects for a new class of biocontrol bacteria. | our group studies tomato foot and root rot, a plant disease caused by the fungus forl (fusarium oxysporum f.sp. radicis-lycopersici ). several bacteria have been described to be able to control the disease, using different mechanisms. here we describe a method that enables us to select, after application of a crude rhizobacterial mixture on a sterile seedling, those strains that reach the root tip faster than our best tomato root colonizer tested so far, the pseudomonas fluorescens biocontrol st ... | 2005 | 16232295 |
| regulatory roles of psra and rpos in phenazine-1-carboxamide synthesis by pseudomonas chlororaphis pcl1391. | production of the secondary metabolite phenazine-1-carboxamide (pcn) by pseudomonas chlororaphis pcl1391 is crucial for biocontrol activity against the phytopathogen fusarium oxysporum f. sp. radicis lycopersici on tomato. regulation of pcn production involves the two-component signalling system gacs/gaca, the quorum-sensing system phzi/phzr and the regulator psra. this paper reports that a functional rpos is required for optimal pcn and n-hexanoyl-l-homoserine lactone (c(6)-hsl) production. con ... | 2006 | 16385114 |
| effect of compost on rhizosphere microflora of the tomato and on the incidence of plant growth-promoting rhizobacteria. | four commercial composts were added to soil to study their effect on plant growth, total rhizosphere microflora, and incidence of plant growth-promoting rhizobacteria (pgpr) in the rhizosphere of tomato plants. three of the compost treatments significantly improved plant growth, while one compost treatment significantly depressed it. compost amendments caused only small variations in the total numbers of bacteria, actinomycetes, and fungi in the rhizosphere of tomato plants. a total of 709 bacte ... | 1995 | 16534902 |
| subcellular localization of chitinase and of its potential substrate in tomato root tissues infected by fusarium oxysporum f. sp. radicis-lycopersici. | antiserum raised against a tomato (lycopersicon esculentum mill.) chitinase (molecular mass of 26 kilodaltons) was used as a probe to study the subcellular localization of this enzyme in tomato root tissues infected with fusarium oxysporum f. sp. radicis-lycopersici. a time-course experiment revealed that chitinase accumulated earlier in the incompatible interaction than in the compatible one. however, in both systems, chitinase deposition was largely correlated with pathogen distribution. the e ... | 1990 | 16667378 |
| implication of pectic components in cell surface interactions between tomato root cells and fusarium oxysporum f. sp. radicis-lycopersici: a cytochemical study by means of a lectin with polygalacturonic acid-binding specificity. | aplysia gonad lectin, a polygalacturonic acid-binding lectin isolated from the sea mollusc aplysia depilans, was complexed to colloidal gold and used for localizing polygalacturonic-acid-containing molecules in tomato root tissues infected with fusarium oxysporum f. sp. radicis-lycopersici (forl). colonization of host tissues by forl was associated with striking wall modifications including disruption and even loss of middle lamellae. according to the labeling pattern observed in host wall areas ... | 1990 | 16667417 |
| effects of the tomato pathogen fusarium oxysporum f. sp. radicis-lycopersici and of the biocontrol bacterium pseudomonas fluorescens wcs365 on the composition of organic acids and sugars in tomato root exudate. | the effects of the pathogenic fungus fusarium oxysporum f. sp. radicis-lycopersici and of the bacterial biocontrol strain pseudomonas fluorescens wcs365, and of both microbes, on the amounts and composition of root exudate components of tomato plants grown in a gnotobiotic stonewool substrate system were studied. conditions were selected under which introduction of f. oxysporum f. sp. radicis-lycopersici caused severe foot and root rot, whereas inoculation of the seed with p. fluorescens wcs365 ... | 2006 | 17022176 |
| selection of bacteria able to control fusarium oxysporum f. sp. radicis-lycopersici in stonewool substrate. | tomato foot and root rot (tfrr), caused by fusariumoxysporum f. sp. radicis-lycopersici (forl), is an economically important disease of tomato. the aim of this study was to develop an efficient protocol for the isolation of bacteria, which controls tfrr based on selection of enhanced competitive root-colonizing bacteria from total rhizosphere soil samples. | 2007 | 17241352 |
| collimonas fungivorans, an unpredicted in vitro but efficient in vivo biocontrol agent for the suppression of tomato foot and root rot. | although bacteria from the genus collimonas have demonstrated in vitro antifungal activity against many different fungi, they appeared inactive against the plant-pathogenic fungus fusarium oxysporum f.sp. radicis-lycopersici (forl), the causal agent of tomato foot and root rot (tfrr). visualization studies using fluorescently labelled organisms showed that bacterial cells attached extensively to the fungal hyphae under nutrient-poor conditions but not in glucose-rich armstrong medium. collimonas ... | 2007 | 17504497 |
| effect of chitosan on hyphal growth and spore germination of plant pathogenic and biocontrol fungi. | to investigate the toxic effect of chitosan on important root pathogenic and biocontrol fungi (nematophagous, entomopathogenic and mycoparasitic). | 2008 | 17927761 |
| isolation and characterization of antagonistic bacillus subtilis strains from the avocado rhizoplane displaying biocontrol activity. | this study was undertaken to isolate bacillus subtilis strains with biological activity against soil-borne phytopathogenic fungi from the avocado rhizoplane. | 2007 | 17953605 |
| role of ethylene in the protection of tomato plants against soil-borne fungal pathogens conferred by an endophytic fusarium solani strain. | an endophytic fungal isolate (fs-k), identified as a fusarium solani strain, was obtained from root tissues of tomato plants grown on a compost which suppressed soil and foliar pathogens. strain fs-k was able to colonize root tissues and subsequently protect plants against the root pathogen fusarium oxysporum f.sp. radicis-lycopersici (forl), and elicit induced systemic resistance against the tomato foliar pathogen septoria lycopersici. interestingly, attenuated expression of certain pathogenesi ... | 2007 | 18048373 |
| cytological aspects of compost-mediated induced resistance against fusarium crown and root rot in tomato. | abstract the potential of a pulp and paper mill residues compost for the control of crown and root rot of greenhouse-grown tomato caused by fusarium oxysporum f. sp. radicis-lycopersici was ultrastructurally investigated. peat moss amended with compost substantially reduced disease-associated symptoms. addition of pythium oligandrum to either peat moss alone or peat moss amended with compost resulted in a considerable reduction in disease incidence compared with controls grown in peat moss alone ... | 2002 | 18942956 |
| disease development following infection of tomato and basil foliage by airborne conidia of the soilborne pathogens fusarium oxysporum f. sp. radicis-lycopersici and f. oxysporum f. sp. basilici. | abstract fusarium oxysporum f. sp. radicis-lycopersici, the causal agent of fusarium crown and root rot of tomato, and f. oxysporum f. sp. basilici, the causal agent of fusarium wilt in basil, are soilborne pathogens capable of producing conspicuous masses of macroconidia along the stem. the role of the airborne propagules in the epidemics of the disease in tomato plants was studied. in the field, airborne propagules of f. oxysporum f. sp. radicis-lycopersici were trapped with a selective medium ... | 2000 | 18943372 |
| controlled laboratory system to study soil solarization and organic amendment effects on plant pathogens. | abstract a controlled laboratory system for simulating soil solarization, with and without organic amendment, was developed and validated using physical, chemical, and biological parameters. the system consists of soil containers that are exposed to controlled and constant aeration, and to temperature fluctuations that resemble those occurring during solarization at various depths. this system enables a separate analysis of volatiles and other components. we recorded a sharp decrease in oxygen c ... | 2007 | 18943518 |
| development of crown and root rot disease of tomato under irrigation with saline water. | abstract we studied the effect of water salinity on the incidence and severity of crown and root rot disease of tomato, as well as on the pathogen and on the plant's response to the pathogen. irrigation with saline water significantly increased disease severity in tomato transplants inoculated with fusarium oxysporum f. sp. radicis-lycopersici, and mineral fertilization further increased it. in one field experiment, disease incidence in plots irrigated with saline water (electrical conductivity ... | 2005 | 18943555 |
| modeling the survival of two soilborne pathogens under dry structural solarization. | abstract structural (space) solarization of a closed, empty greenhouse for sanitation involves dry heating to 60 degrees c and higher and low relative humidity (rh), under a fluctuating temperature and rh regime. survival of inocula of fusarium oxysporum f. sp. radicis-lycopersici and sclerotium rolfsii during structural solarization was studied for 4 years (total of 12 experiments) in an attempt to develop a dynamic model for expressing the thermal inactivation of the pathogens. after 20 days o ... | 2003 | 18944324 |
| population genetic analysis corroborates dispersal of fusarium oxysporum f. sp. radicis-lycopersici from florida to europe. | abstract fusarium oxysporum isolates from tomato plants displaying crown and root rot symptoms were collected in central and southern florida and analyzed using vegetative compatibility grouping (vcg) and nuclear restriction fragment length polymorphism (rflp) data. vcg 0094 of f. oxysporum f. sp. radicis-lycopersici, previously known only from northwestern europe, was predominant among 387 isolates assessed. in addition, two newly described vcgs (0098 and 0099) were detected at low frequencies. ... | 1999 | 18944673 |
| spatial distribution and temporal development of fusarium crown and root rot of tomato and pathogen dissemination in field soil. | abstract the spatial distribution and temporal development of tomato crown and root rot, caused by fusarium oxysporum f. sp. radicis-lycopersici, were studied in naturally infested fields in 1996 and 1997. disease progression fit a logistic model better than a monomolecular one. geostatistical analyses and semivariogram calculations revealed that the disease spreads from infected plants to a distance of 1.1 to 4.4 m during the growing season. by using a chlorate-resistant nitrate nonutilizing (n ... | 1999 | 18944713 |
| ultrastructural and cytochemical aspects of the interaction between the mycoparasite pythium oligandrum and soilborne plant pathogens. | abstract the interaction between the oomycete pythium oligandrum and various soilborne oomycete and fungal plant pathogens (p. ultimum, p. aphanidermatum, fusarium oxysporum f. sp. radicis-lycopersici, verticillium albo-atrum, rhizoctonia solani, and phytophthora megasperma) was studied by light and electron microscopy in order to assess the relative contribution of mycoparasitism and antibiosis in the antagonistic process. scanning electron microscope investigations of the interaction regions s ... | 1999 | 18944723 |
| zinc improves biocontrol of fusarium crown and root rot of tomato by pseudomonas fluorescens and represses the production of pathogen metabolites inhibitory to bacterial antibiotic biosynthesis. | abstract crown and root rot of tomato caused by fusarium oxysporum f. sp. radicis-lycopersici is an increasing problem in europe, israel, japan, and north america. the biocontrol agent pseudomonas fluorescens strain cha0 provides only moderate control of this disease. a one-time amendment of zinc edta at 33 mug of zn(2+)/ml to hydroponic nutrient solution in soilless rockwool culture did not reduce disease when used alone, but did reduce disease by 25% in the presence of cha0. in in vitro studie ... | 1997 | 18945026 |
| treatment with the mycoparasite pythium oligandrum triggers induction of defense-related reactions in tomato roots when challenged with fusarium oxysporum f. sp. radicis-lycopersici. | abstract the influence exerted by the mycoparasite pythium oligandrum in triggering plant defense reactions was investigated using an experimental system in which tomato plants were infected with the crown and root rot pathogen fusarium oxysporum f. sp. radicis-lycopersici. to assess the antagonistic potential of p. oligandrum against f. oxysporum f. sp. radicis-lycopersici, the interaction between the two fungi was studied by scanning and transmission electron microscopy (sem and tem, respectiv ... | 1997 | 18945162 |
| 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 ... | 2010 | 21534476 |
| pseudomonas fluorescens f113 mutant with enhanced competitive colonization ability and improved biocontrol activity against fungal root pathogens. | motility is one of the most important traits for efficient rhizosphere colonization by pseudomonas fluorescens f113rif (f113). in this bacterium, motility is a polygenic trait that is repressed by at least three independent pathways, including the gac posttranscriptional system, the wsp chemotaxis-like pathway, and the sadb pathway. here we show that the kinb gene, which encodes a signal transduction protein that together with algb has been implicated in alginate production, participates in swim ... | 2011 | 21685161 |
| structural characterization of the o-chain polysaccharide from an environmentally beneficial bacterium pseudomonas chlororaphis subsp. aureofaciens strain m71. | pseudomonas chlororaphis subsp. aureofaciens strain m71 was isolated from the root of a tomato plant and it was able to control in vivo fusarium oxysporum f. sp. radicis-lycopersici responsible for the tomato crown and root rot. recently, strain m71 was evaluated even for its efficacy in controlling seiridium cardinale, the causal agent of bark canker of common cypress (cupressus sempervirens l.). strain m71 ability to persist on the tomato rhizosphere and on the aerial part of cypress plants co ... | 2011 | 22036123 |
| evaluation of plant-growth-promoting rhizobacteria, acibenzolar-s-methyl and hymexazol for integrated control of fusarium crown and root rot on tomato. | plant growth-promoting rhizobacteria (pgpr) can be potential agents for biological control of plant pathogens, while their combined use with conventional pesticides may increase their efficacy and broaden the disease control spectrum. the effect of four different bacillus sp. pgpr strains (b. subtilis gb03 and fzb24, b. amyloliquefaciens in937a and b. pumilus se34) applied individually and in mixtures, as well as in combined use with acibezolar-s-methyl (asm) and hymexazol, on plant growth promo ... | 2011 | 22307860 |
| the pseudomonas chlororaphis pcl1391 sigma regulator psra represses the production of the antifungal metabolite phenazine-1-carboxamide. | the rhizobacterium pseudomonas chlororaphis pcl1391 produces the antifungal metabolite phenazine-1-carboxamide (pcn), which is a crucial trait in its competition with the phytopathogenic fungus fusarium oxysporum f. sp. radicis-lycopersici in the rhizosphere. the expression of the pcn biosynthetic gene cluster in pcl1391 is population density-dependent and is regulated by the quorum-sensing genes phzi and phzr via synthesis of the autoinducer n-hexanoyl-l-homoserine lactone (c6-hsl). here, we de ... | 2005 | 15782638 |
| role of chemotaxis toward fusaric acid in colonization of hyphae of fusarium oxysporum f. sp. radicis-lycopersici by pseudomonas fluorescens wcs365. | pseudomonas fluorescens wcs365 is an excellent competitive colonizer of tomato root tips after bacterization of seed or seedlings. the strain controls tomato foot and root rot (tfrr) caused by the phytopathogenic fungus fusarium oxysporum f. sp. radicis-lycopersici. under biocontrol conditions, fungal hyphae were shown to be colonized by wcs365 bacteria. because chemotaxis is required for root colonization by wcs365 cells, we studied whether chemotaxis also is required for hyphae colonization. t ... | 2004 | 15553244 |
| chitinase-gold complex used to localize chitin ultrastructurally in tomato root cells infected by fusarium oxysporum f. sp. radicis-lycopersici, compared with a chitin specific gold-conjugated lectin. | a cytochemical technique for the ultrastructural localization of chitin in tomato root cells infected by fusarium oxysporum f. sp. radicis-lycopersici is reported. chitinase was complexed to colloidal gold and thin sections were incubated with the enzyme-gold complex. this technique yielded a more uniform distribution of gold particles over the fungus wall, compared to that obtained with the lectin-gold technique. both techniques revealed no labelling of the fungus cytoplasm, except for organell ... | 1985 | 2411684 |