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[the structure of the o-specific polysaccharide from a mutant of nitrogen-fixing rhizobacterium azospirillum brasilense sp245 with an altered plasmid content].the rhizobacteria azospirillum brasilense sp245 produce antigenically different lipopolysaccharides lpsi and lpsii, both containing identical pentasaccharides built from d-rhamnose residues as the repeated chains of o-specific oligosaccharides (ops). in this study, we report the structure of the ops from a. brasilense lpsi(-)lpsii(-)-mutant sp245.5, which spontaneously lost the p85 and p120 plasmids upon the formation of a new 300-mda megaplasmid after the long-term storage of the bacteria in a ...201020531482
gene encoding gamma-carbonic anhydrase is cotranscribed with argc and induced in response to stationary phase and high co2 in azospirillum brasilense sp7.carbonic anhydrase (ca) is a ubiquitous enzyme catalyzing the reversible hydration of co2 to bicarbonate, a reaction underlying diverse biochemical and physiological processes. gamma class carbonic anhydrases (gamma-cas) are widespread in prokaryotes but their physiological roles remain elusive. at present, only gamma-ca of methanosarcina thermophila (cam) has been shown to have ca activity. genome analysis of a rhizobacterium azospirillum brasilense, revealed occurrence of orfs encoding one bet ...201020598158
growth of quailbush in acidic, metalliferous desert mine tailings: effect of azospirillum brasilense sp6 on biomass production and rhizosphere community structure.mine tailing deposits in semiarid and arid environments frequently remain devoid of vegetation due to the toxicity of the substrate and the absence of a diverse soil microbial community capable of supporting seed germination and plant growth. the contribution of the plant growth promoting bacterium (pgpb) azospirillum brasilense sp6 to the growth of quailbush in compost-amended, moderately acidic, high-metal content mine tailings using an irrigation-based reclamation strategy was examined along ...201020632001
capsular polysaccharide of the bacterium azospirillum lipoferum sp59b: structure and antigenic specificity.antigenic differences were revealed between the cell wall outer membrane lipopolysaccharides and the capsular high molecular weight bioglycans for a typical strain of the nitrogen-fixing rhizobacterium azospirillum lipoferum sp59b using antibodies prepared against the homologous lipopolysaccharide and lipopolysaccharide-protein complex. from the capsular lipopolysaccharide-protein and polysaccharide-lipid complexes of a. lipoferum sp59b, polysaccharides were isolated and their structure was for ...201020632940
[localization of denitrification genes in plasmid dna of bacteria azospirillum brasilense].in 85-mda plasmid (p85) of plant-associated bacteria azospirillum brasilense sp245 model strain, the genes encoding copper-containing nitrite reductase (nirk); heterodimeric no-reductase (norcb); norq and nord proteins affecting synthesis and (or) activation of nirk and (or) no-reductase (norqd); catalytic subunit i ofcytochrom c oxidase (cccon); presumable no sensor carrying two hemeerythrine domains (orf181); and an enzyme required for synthesis of presumable no antagonist, homocystein (metc) ...201020795494
the auxin-signaling pathway is required for the lateral root response of arabidopsis to the rhizobacterium phyllobacterium brassicacearum.plant root development is highly responsive both to changes in nitrate availability and beneficial microorganisms in the rhizosphere. we previously showed that phyllobacterium brassicacearum stm196, a plant growth-promoting rhizobacteria strain isolated from rapeseed roots, alleviates the inhibition exerted by high nitrate supply on lateral root growth. since soil-borne bacteria can produce iaa and since this plant hormone may be implicated in the high nitrate-dependent control of lateral root d ...201020844890
isolation of oligotrophic denitrifiers carrying previously uncharacterized functional gene sequences.oligotrophic denitrifying bacteria, including those belonging to the genera herbaspirillum, azospirillum, and bradyrhizobium, were obtained using a single-cell isolation technique. the taxonomic composition of the denitrifier population was similar to those assessed by previous culture-independent studies. the sequencing of nitrite reductase and n(2)o reductase genes of these strains revealed previously unknown links between 16s rrna and the denitrification-functional gene phylogenies. in partic ...201021075882
low endotoxic activity of lipopolysaccharides isolated from bradyrhizobium, mesorhizobium, and azospirillum strains.the endotoxic activities of lipopolysaccharides (lps) isolated from different strains of rhizobia and rhizobacteria (bradyrhizobium, mesorhizobium, and azospirillum) were compared to those of salmonella enterica sv. typhimurium lps. the biological activity of all the examined preparations, measured as limulus lysate gelation, production of tumor necrosis factor (tnf), interleukin-1β (il-1β), and interleukin-6 (il-6), and nitrogen oxide (no) induction in human myelomonocytic cells (line thp-1), w ...201021091983
characterization of cell surface and extracellular matrix remodeling of azospirillum brasilense chemotaxis-like 1 signal transduction pathway mutants by atomic force microscopy.to compete in complex microbial communities, bacteria must sense environmental changes and adjust cellular functions for optimal growth. chemotaxis-like signal transduction pathways are implicated in the regulation of multiple behaviors in response to changes in the environment, including motility patterns, exopolysaccharide production, and cell-to-cell interactions. in azospirillum brasilense, cell surface properties, including exopolysaccharide production, are thought to play a direct role in ...201021105907
dynamics, diversity and function of endophytic siderophore-producing bacteria in rice.siderophore production confers to bacteria competitive advantages to colonize plant tissues and to exclude other microorganisms from the same ecological niche. this work shows that the community of endophytic siderophore-producing bacteria (spb) associated to oryza sativa cultivated in uruguayan soils is dynamic and diverse. these bacteria were present in grains, roots, and leaves, and their density fluctuated between log(10) 3.44 and log(10) 5.52 cfu g(-1) fresh weight (fw) during the plant gro ...201021128071
bacterial communities associated with the lichen symbiosis.lichens are commonly described as a mutualistic symbiosis between fungi and "algae" (chlorophyta or cyanobacteria); however, they also have internal bacterial communities. recent research suggests that lichen-associated microbes are an integral component of lichen thalli and that the classical view of this symbiotic relationship should be expanded to include bacteria. however, we still have a limited understanding of the phylogenetic structure of these communities and their variability across li ...201021169444
genetic and phenotypic diversity of plant growth promoting rhizobacteria isolated from sugarcane plants growing in pakistan.bacteria were isolated from roots of sugarcane varieties grown in the fields of punjab. they were identified by using api20e/ne bacterial identification kits and from sequences of 16s rrna and amplicons of the cpn60 gene. the majority of bacteria were found to belong to the genera of enterobacter, pseudomonas, and klebsiella, but members of genera azospirillum, rhizobium, rahnella, delftia, caulobacter, pannonibacter, xanthomonas, and stenotrophomonas were also found. the community, however, was ...201021193815
systemic induction of monoterpene biosynthesis in origanumxmajoricum by soil bacteria.italian oregano (origanumxmajoricum) was subjected to root system inoculation with three species of plant growth-promoting rhizobacteria (pgprs) (pseudomonas fluorescens, bacillus subtilis, azospirillum brasilense), and essential oil (eo) content and plant growth were measured. composition of monoterpenes, a major eo component, was analyzed qualitative and quantitatively by gas chromatography. total eo yield for plants inoculated with p. fluorescens or a. brasilense was 3.57 and 3.41 microg/mg f ...201020000572
synthesis of a tetrasaccharide related to the o-antigen from azospirillum lipoferum sr65.concise synthesis of a tetrasaccharide repeating unit of the lps isolated from azospirillum lipoferum sr65 has been accomplished through suitable protecting group manipulations and stereoselective glycosylation starting from commercially available l-rhamnose and d-glucose. the target oligosaccharide in the form of its p-methoxyphenyl glycoside is suitable for further glycoconjugate formation via selective cleavage of the omp glycoside. plant growth-promoting bacteria (pgpb) of genus azospirillum ...201020035930
complete genomic structure of the cultivated rice endophyte azospirillum sp. b510.we determined the nucleotide sequence of the entire genome of a diazotrophic endophyte, azospirillum sp. b510. strain b510 is an endophytic bacterium isolated from stems of rice plants (oryza sativa cv. nipponbare). the genome of b510 consisted of a single chromosome (3,311,395 bp) and six plasmids, designated as pab510a (1,455,109 bp), pab510b (723,779 bp), pab510c (681,723 bp), pab510d (628,837 bp), pab510e (537,299 bp), and pab510f (261,596 bp). the chromosome bears 2893 potential protein-enc ...201020047946
azospirillum thiophilum sp. nov., a diazotrophic bacterium isolated from a sulfide spring.a novel nitrogen-fixing strain, designated bv-s(t), was isolated from a sulfur bacterial mat collected from a sulfide spring of the stavropol krai, north caucasus, russia. strain bv-s(t) grew optimally at ph 7.5 and 37°c. according to the results of phylogenetic analysis, strain bv-s(t) belonged to the genus azospirillum within the family rhodospirillaceae of the class alphaproteobacteria. within the genus azospirillum, strain bv-s(t) was most closely related to azospirillum doebereinerae gsf71( ...201020081019
pas domain containing chemoreceptor couples dynamic changes in metabolism with chemotaxis.chemoreceptors provide sensory specificity and sensitivity that enable motile bacteria to seek optimal positions for growth and metabolism in gradients of various physicochemical cues. despite the abundance of chemoreceptors, little is known regarding the sensory specificity and the exact contribution of individual chemoreceptors to the lifestyle of bacteria. azospirillum brasilense are motile bacteria that can fix atmospheric nitrogen under microaerophilic conditions. here, we characterized a c ...201020133866
effects of azospirillum brasilense with genetically modified auxin biosynthesis gene ipdc upon the diversity of the indigenous microbiota of the wheat rhizosphere.the phytostimulatory properties of azospirillum inoculants, which entail production of the phytohormone indole-3-acetic acid (iaa), can be enhanced by genetic means. however, it is not known whether this could affect their interactions with indigenous soil microbes. here, wheat seeds were inoculated with the wild-type strain azospirillum brasilense sp245 or one of three genetically modified (gm) derivatives and grown for one month. the gm derivatives contained a plasmid vector harboring the indo ...201020138146
assessment of scar markers to design real-time pcr primers for rhizosphere quantification of azospirillum brasilense phytostimulatory inoculants of maize.to assess the applicability of sequence characterized amplified region (scar) markers obtained from box, eric and rapd fragments to design primers for real-time pcr quantification of the phytostimulatory maize inoculants azospirillum brasilense uap-154 and cfn-535 in the rhizosphere.201020141548
changes in pelagic bacteria communities due to leaf litter addition.in many limnetic systems, the input of allochthonous organic matter, e.g., leaf litter, is a substantial source of dissolved organic carbon (doc) for pelagic bacteria, especially in fall and winter when autochthonous doc production is low. however, relatively little is known about community changes of pelagic lake bacteria due to leaf litter input which includes both the release of leaf leachates and microorganisms from the leaf litter into the surrounding water. therefore, we have experimentall ...201020198369
[electrooptical properties of the microbial suspensions during a cell's interaction with the antibodies of a different specificity].the electrooptical abilities of the microbial suspensions during a cells interaction with antibodies (abs) of a different specificity have been studied on the example of the azospirillum brasilense sp245 cells and their interaction with the polyclonal monospecific and polyspecific antibodies. measuring of the orientational spectra of the cells has been performed using the elus electrooptical analyzer. a discrete frequency set of an orienting electric field (740, 1000, 1450, 2000, and 2800 khz) w ...201020198920
[effect of lectins from azospirillum brasilense to peroxidase and oxalate oxidase activity regulation in wheat roots].lectins were extracted from the surface of nitrogen-fixing soil bacteria azospirillum brasilense sp7 and from its mutant a. brasilense sp7.2.3 defective in lectin activity. the ability oflectins to stimulate the rapid formation of hydrogen peroxide related to increase of oxalate oxidase and peroxidase activity in the roots of wheat seedlings has been demonstrated. the most rapid induced pathway of hydrogen peroxide formation in the roots of wheat seedlings was the oxalic acid oxidation by oxalat ...201020235434
bacterial community associated with healthy and diseased reef coral mussismilia hispida from eastern brazil.in order to characterize the bacterial community diversity associated to mucus of the coral mussismilia hispida, four 16s rdna libraries were constructed and 400 clones from each library were analyzed from two healthy colonies, one diseased colony and the surrounding water. nine bacterial phyla were identified in healthy m. hispida, with a dominance of proteobacteria, actinobacteria, acidobacteria, lentisphaerae, and nitrospira. the most commonly found species were related to the genera azospiri ...201020352207
[plasmid rearrangements and azospirillum brasilense biofilm formation]. 201020411670
transformation of the water soluble fraction from "alpeorujo" by coriolopsis rigida: the role of laccase in the process and its impact on azospirillum brasiliense survival.the objective of this work was to evaluate the ability of the white rot basidiomycete coriolopsis rigida to detoxify the water soluble fraction from "alpeorujo" (wsfa), a solid by-product produced by the olive oil extraction industry and characterized by a high concentration of phenols which limits its use as fertilizer and/or amendment. c. rigida reduced the phenol content in the liquid media supplemented with wsfa at 10 and 20% (v/v) after 15d of incubation. the analysis of wsfa toxicity after ...201019875147
changes in cucumber hypocotyl cell wall dynamics caused by azospirillum brasilense inoculation.we previously reported that azospirillum brasilense induced a more elastic cell wall and a higher apoplastic water fraction in both wheat coleoptile and flag leaf. these biophysical characteristics could permit increased growth. knowledge of the biochemical effects the bacteria could elicit in plant cell walls and how these responses change plant physiology is still scarce. the objective of this work was to analyze whether a. brasilense sp245 inoculation affected elongation and extensibility of ...201019875302
isolation of functional single cells from environments using a micromanipulator: application to study denitrifying bacteria.we developed a novel method to isolate functionally active single cells from environmental samples and named it the functional single-cell (fsc) isolation method. this method is based on a combination of substrate-responsive direct viable counts, live-cell staining with 5-carboxyfluorescein diacetate acetoxymethyl ester, and micromanipulation followed by cultivation in a medium. to evaluate this method, we applied it to study a denitrifying community in rice paddy soil. similar denitrifier count ...201019936739
applicability of the 16s-23s rdna internal spacer for pcr detection of the phytostimulatory pgpr inoculant azospirillum lipoferum crt1 in field soil.to assess the applicability of the 16s-23s rdna internal spacer regions (isr) as targets for pcr detection of azospirillum ssp. and the phytostimulatory plant growth-promoting rhizobacteria seed inoculant azospirillum lipoferum crt1 in soil.201019583800
[ estimation of azospirillum lectins effect on camp level in plant cell ]. 201021774174
identification and isolation of active n(2)o reducers in rice paddy soil.dissolved n(2)o is occasionally detected in surface and ground water in rice paddy fields, whereas little or no n(2)o is emitted to the atmosphere above these fields. this indicates the occurrence of n(2)o reduction in rice paddy fields; however, identity of the n(2)o reducers is largely unknown. in this study, we employed both culture-dependent and culture-independent approaches to identify n(2)o reducers in rice paddy soil. in a soil microcosm, n(2)o and succinate were added as the electron ac ...201121677691
changes in the bacterial community structure and diversity during bamboo retting.microbial retting is a critical step in obtaining fiber bundles from bamboo culm using indigenous microorganisms. a cultivation-independent technique for monitoring the changes in bacteria community during bamboo retting was applied in this work. this technique involves genetic profiling of pcr-amplified small-subunit rrna and the single-strand conformation polymorphism (sscp) gel analysis of the pcr-amplified 16s rdna fragments. the study revealed that both the structure and the diversity of in ...201121695788
Azospirillum formosense sp. nov., a novel diazotrophic bacterium isolated from agricultural soil.A Gram-negative, spiral or rod-shaped, non-spore-forming diazotrophic bacterium (strain CC-Nfb-7T), was isolated from agricultural soil located in Yunlin County, Taiwan. The 16S rRNA gene sequence analysis of strain CC-Nfb-7T showed highest sequence similarity to Azospirillum brasilense DSM 1690T (97.4%), Azospirillum rugosum DSM 19657T (96.8%), and Azospirillum oryzae JCM 21588T (96.6%) and lower sequence similarity (< 96.5%) to all other Azospirillum species. DNA-DNA hybridizations of strain C ...201121742820
heat stability of proteobacterial pii protein facilitate purification using a single chromatography step.the p(ii) proteins comprise a family of widely distributed signal transduction proteins that integrate the signals of cellular nitrogen, carbon and energy status, and then regulate, by protein-protein interaction, the activity of a variety of target proteins including enzymes, transcriptional regulators and membrane transporters. we have previously shown that the p(ii) proteins from azospirillum brasilense, glnb and glnz, do not alter their migration behavior under native gel electrophoresis fol ...201121963770
effect of genomic rearrangement on heavy metal tolerance in the plant-growth-promoting rhizobacterium azospirillum brasilense sp245.a derivative of azospirillum brasilense sp245, sp245.5, which spontaneously lost 85 and 120 mda replicons upon the formation of a new megaplasmid, has been shown to produce a novel lipopolysaccharide and to lose calcofluor-binding polysaccharides. as compared to sp245, the derivative displays notably increased heavy metal tolerance. the phenotypes of sp245 and sp245.5 are characterized by the following minimal inhibitory concentrations (mics) of heavy metals: 0.5 and 0.9 μmol l(-1) of ag(+), 0.4 ...201122130692
crystal structure of the glnz-drag complex reveals a different form of pii-target interaction.nitrogen metabolism in bacteria and archaea is regulated by a ubiquitous class of proteins belonging to the p(ii)family. p(ii) proteins act as sensors of cellular nitrogen, carbon, and energy levels, and they control the activities of a wide range of target proteins by protein-protein interaction. the sensing mechanism relies on conformational changes induced by the binding of small molecules to p(ii) and also by p(ii) posttranslational modifications. in the diazotrophic bacterium azospirillum b ...201122074780
An improved rapid method for the preparation of d-rhamnose.A method is developed for the preparation of d-rhamnose from an O-polysaccharide (OPS) isolated by mild acid hydrolysis of Azospirillum brasilense SR75 cell mass. After the OPS hydrolysis, d-rhamnose was recovered by gel-permeation chromatography on Toyopearl TSK HW-40 and was crystallized. The sugar activity was demonstrated immunochemically. The advantages of the method are that it expedites and simplifies the extraction of d-rhamnose and increases its yield.201122099380
characterization of nitrogen-fixing bacteria isolated from field-grown barley, oat, and wheat.diazotrophic bacteria were isolated from the rhizosphere of field-grown triticum aestivum, hordeum vulgare, and avena sativa grown in various regions of greece. one isolate, with the highest nitrogen-fixation ability from each of the eleven rhizospheres, was selected for further characterisation. diazotrophic strains were assessed for plant-growth-promoting traits such as indoleacetic acid production and phosphate solubilisation. the phylogenies of 16s rrna gene of the selected isolates were com ...201121887633
Structural peculiarities of the O-specific polysaccharides of Azospirillum bacteria of serogroup III.Lipopolysaccharides and O-specific polysaccharides were isolated from the outer membrane of bacterial cells of three strains belonging to two Azospirillum species, and their structures were established by monosaccharide analysis including determination of the absolute configurations, methylation analysis, and one- and two-dimensional NMR spectroscopy. It was shown that while having the identical composition, the O-polysaccharides have different branched tetrasaccharide repeating units. Two neutr ...201121999541
tools for genetic manipulation of the plant growth-promoting bacterium azospirillum amazonense.abstract: background: azospirillum amazonense has potential to be used as agricultural inoculant since it promotes plant growth without causing pollution, unlike industrial fertilizers. owing to these facts, the study of this species has gained interest. however, a detailed understanding of its genetics and physiology is limited by the absence of appropriate genetic tools for the study of this species. results: conjugation and electrotransformation methods were established utilizing vectors with ...201121575234
the chemotaxis-like che1 pathway has an indirect role in adhesive cell properties of azospirillum brasilense.the azospirillum brasilense chemotaxis-like che1 signal transduction pathway was recently shown to modulate changes in adhesive cell surface properties that, in turn, affect cell-to-cell aggregation and flocculation behaviors rather than flagellar-mediated chemotaxis. attachment to surfaces and root colonization may be functions related to flocculation. here, the conditions under which a. brasilense wild-type sp7 and che1 mutant strains attach to abiotic and biotic surfaces were examined using i ...201122092709
Diversity of 16S rRNA genes from bacteria of sugarcane rhizosphere soil.Sugarcane is an important agricultural product of Brazil, with a total production of more than 500 million tons. Knowledge of the bacterial community associated with agricultural crops and the soil status is a decisive step towards understanding how microorganisms influence crop productivity. However, most studies aim to isolate endophytic or rhizosphere bacteria associated with the plant by culture-dependent approaches. Culture-independent approaches allow a more comprehensive view of entire ba ...201122042267
Alginate beads provide a beneficial physical barrier against native microorganisms in wastewater treated with immobilized bacteria and microalgae.When the freshwater microalga Chlorella sorokiniana and the plant growth-promoting bacterium Azospirillum brasilense were deployed as free suspensions in unsterile, municipal wastewater for tertiary wastewater treatment, their population was significantly lower compared with their populations in sterile wastewater. At the same time, the numbers of natural microfauna and wastewater bacteria increased. Immobilization of C. sorokiniana and A. brasilense in small (2-4 mm in diameter), polymer Ca-alg ...201122038243
elstera litoralis gen. nov., sp. nov. isolated from stone biofilms of lake constance after enrichment with diatom exudates.an alphaproteobacterium, strain dia-1t, was isolated from algae-dominated biofilms on stones from the littoral zone of lake constance, germany. this bacterium was isolated after initial enrichment in spent medium obtained after growth of a diatom culture. numerous sugars and few organic acids and alcohols serve as growth substrate. the bacterium grows slowly, is strictly aerobic but microaerophilic, and does not grow in cultures shaken under air. 16s rrna gene sequence analysis indicated that st ...201121948090
Field monitoring of plant-growth-promoting rhizobacteria by colony immunoblotting.Inoculant plant-growth-promoting bacteria are emerging as an important component of sustainable agriculture. There is a need to develop inexpensive methods for enumerating these organisms after their application in the field, to better understand their survival and impacts on yields. Immunoblotting is one potential method to measure viable cells, but the high cost of the conventionally used nylon membranes makes this method prohibitive. In this study, less expensive alternative materials such as ...201122017658
azospirillum genomes reveal transition of bacteria from aquatic to terrestrial environments.fossil records indicate that life appeared in marine environments ∼3.5 billion years ago (gyr) and transitioned to terrestrial ecosystems nearly 2.5 gyr. sequence analysis suggests that "hydrobacteria" and "terrabacteria" might have diverged as early as 3 gyr. bacteria of the genus azospirillum are associated with roots of terrestrial plants; however, virtually all their close relatives are aquatic. we obtained genome sequences of two azospirillum species and analyzed their gene origins. while m ...201122216014
cyclic gmp controls rhodospirillum centenum cyst development.adenylyl cyclases are widely distributed across all kingdoms whereas guanylyl cyclases are generally thought to be restricted to eukaryotes. here we report that the α-proteobacterium rhodospirillum centenum secretes cgmp when developing cysts and that a guanylyl cyclase deletion strain fails to synthesize cgmp and is defective in cyst formation. the r. centenum cyclase was purified and shown to effectively synthesize cgmp from gtp in vitro, demonstrating that it is a functional guanylyl cyclase. ...201121214648
a cher/cheb fusion protein is involved in cyst cell development and chemotaxis in azospirillum brasilense sp7.we here report the sequence and functional analysis of cstb of azospirillum brasilense sp7. the predicted cstb contains c-terminal two pas domains and n-terminal part which has similarity with cheb-cher fusion protein. cstb mutants had reduced swarming ability compared to that of a. brasilense wild-type strain, implying that cstb was involved in chemotaxis in a. brasilense. a microscopic analysis revealed that cstb mutants developed mature cyst cells more quickly than wild type, indicating that ...201121232929
an extracytoplasmic function sigma factor cotranscribed with its cognate anti-sigma factor confers tolerance to nacl, ethanol and methylene blue in azospirillum brasilense sp7.azospirillum brasilense, a plant-growth-promoting rhizobacterium, is exposed to changes in its abiotic environment, including fluctuations in temperature, salinity, osmolarity, oxygen concentration and nutrient concentration, in the rhizosphere and in the soil. since extra-cytoplasmic function (ecf) sigma factors play an important role in stress adaptation, we analysed the role of ecf sigma factor (also known as rpoe or s(e)) in abiotic stress tolerance in a. brasilense. an in-frame rpoe deletio ...201121233159
azospirillum brasilense siderophores with antifungal activity against colletotrichum acutatum.anthracnose, caused by the fungus colletotrichum acutatum is one of the most important diseases in strawberry crop. due to environmental pollution and resistance produced by chemical fungicides, nowadays biological control is considered a good alternative for crop protection. among biocontrol agents, there are plant growth-promoting bacteria, such as members of the genus azospirillum. in this work, we demonstrate that under iron limiting conditions different strains of a. brasilense produce side ...201121234749
cdna-aflp analysis of differential gene expression related to cell chemotactic and encystment of azospirillum brasilense.our previous study indicated org35 was involved in chemotaxis and interacted with nitrogen fixation transcriptional activator nifa via pas domain. in order to reveal the role of org35 in nitrogen regulation, the downstream target genes of org35 were identified. we here report differentially expressed genes in org35 mutants comparing with wild type sp7 by means of cdna-aflp. four up-regulated transcript-derived fragments (tdfs) homologues of chemotaxis transduction proteins were found, including ...201121242066
the role of the antimicrobial compound 2,4-diacetylphloroglucinol in the impact of biocontrol pseudomonas fluorescens f113 on azospirillum brasilense phytostimulators.pseudomonads producing the antimicrobial metabolite 2,4-diacetylphloroglucinol (phl) can control soil-borne phytopathogens, but their impact on other plant-beneficial bacteria remains poorly documented. here, the effects of synthetic phl and phl(+) pseudomonas fluorescens f113 on azospirillum brasilense phytostimulators were investigated. most a. brasilense strains were moderately sensitive to phl. in vitro, phl induced accumulation of carotenoids and poly-ß-hydroxybutyrate-like granules, cytopl ...201121273247
rapid detection and identification of the free-living nitrogen fixing genus azospirillum by 16s rrna-gene-targeted genus-specific primers.the modern agricultural practice utilizing plant growth promoting rhizobacteria (pgpr) has brought great benefits in the promotion of crop growth. among pgpr, azospirillum is considered as an important genus which is not only closely-associated with plants but also shows potential in the degradation of organic contaminants. however, lack of media for selective isolation or techniques for specific detection or identification limit the exploration of these rhizobacteria. this motivated us to desig ...201121327476
structural and functional peculiarities of the lipopolysaccharide of azospirillum brasilense sr55, isolated from the roots of triticum durum.azospirillum brasilense sr55, isolated from the rhizosphere of triticum durum, was classified as serogroup ii on the basis of serological tests. such serogroup affiliation is uncharacteristic of wheat-associated azospirillum species. the lipid a of a. brasilense sr55 lipopolysaccharide contained 3-hydroxytetradecanoic, 3-hydroxyhexadecanoic, hexadecanoic and octadecenoic fatty acids. the structure of the lipopolysaccharide's o polysaccharide was established, with the branched octasaccharide repe ...201121334868
transcriptome analysis of the rhizosphere bacterium azospirillum brasilense reveals an extensive auxin response.the rhizosphere bacterium azospirillum brasilense produces the auxin indole-3-acetic acid (iaa) through the indole-3-pyruvate pathway. as we previously demonstrated that transcription of the indole-3-pyruvate decarboxylase (ipdc) gene is positively regulated by iaa, produced by a. brasilense itself or added exogenously, we performed a microarray analysis to study the overall effects of iaa on the transcriptome of a. brasilense. the transcriptomes of a. brasilense wild-type and the ipdc knockout ...201121340736
response to saline stress and aquaporin expression in azospirillum-inoculated barley seedlings.the ability of two strains of azospirillum brasilense to mitigate nacl stress in barley plants was evaluated. barley seedlings were inoculated and subjected to 200 mm nacl for 18 days. several days after nacl treatment, a significant decline in biomass as well as in height was observed in uninoculated plants. however, smaller reductions in biomass and height were detected in plants inoculated with strain az39. all the stressed plants showed significantly higher na(+) but lower k(+) contents in t ...201121365472
azospirillum and arbuscular mycorrhizal colonization enhance rice growth and physiological traits under well-watered and drought conditions.the response of rice plants to inoculation with an arbuscular mycorrhizal (am) fungus, azospirillum brasilense, or combination of both microorganisms, was assayed under well-watered or drought stress conditions. water deficit treatment was imposed by reducing the amount of water added, but am plants, with a significantly higher biomass, received the same amount of water as non-am plants, with a poor biomass. thus, the water stress treatment was more severe for am plants than for non-am plants. t ...201121377754
indole-3-acetic acid biosynthesis in the biocontrol strain pseudomonas fluorescens psd and plant growth regulation by hormone overexpression.pseudomonas fluorescens is an important biological component of agricultural soils that bestows a number of direct and indirect beneficial attributes to the plants. we analyzed the biocontrol strain p. fluorescens psd for indole-3-acetic acid (iaa) biosynthesis and studied the effect of its consequent manipulation on its plant-growth-promoting (pgp) potential. while the indole pyruvic acid (ipya) pathway commonly associated with pgp bacteria was lacking, the indole acetamide (iam) pathway genera ...201121397014
improving casuarina growth and symbiosis with frankia under different soil and environmental conditions--review.casuarinas are very important plants for their various uses and survival in adverse sites or harsh environments. as nitrogen fixation, in symbiosis with frankia, is an important factor for the survival of these plants under various conditions, the basis for selecting both effective and tolerant frankia strains and casuarina spp., are provided. enhancement of the symbiotic relationship between frankia and casuarina, by mycorrhizal infection and other biofertilizing microorganisms such as bacillus ...201121448712
characterization of a thiamin diphosphate-dependent phenylpyruvate decarboxylase from saccharomyces cerevisiae.the product of the aro10 gene from saccharomyces cerevisiae was initially identified as a thiamine diphosphate-dependent phenylpyruvate decarboxylase with a broad substrate specificity. it was suggested that the enzyme could be responsible for the catabolism of aromatic and branched-chain amino acids, as well as methionine. in the present study, we report the overexpression of the aro10 gene product in escherichia coli and the first detailed in vitro characterization of this enzyme. the enzyme i ...201121501384
the genetic diversity of culturable nitrogen-fixing bacteria in the rhizosphere of wheat.a total of 17 culturable nitrogen-fixing bacterial strains associated with the roots of wheat growing in different regions of greece were isolated and characterized for plant-growth-promoting traits such as auxin production and phosphate solubilization. the phylogenetic position of the isolates was first assessed by the analysis of the pcr-amplified 16s rrna gene. the comparative sequence analysis and phylogenetic analysis based on 16s rrna gene sequences show that the isolates recovered in this ...201120857096
soil factors exhibit greater influence than bacterial inoculation on alfalfa growth and nitrogen fixation.in order to study effects of soil factors and bacterial inoculation on alfalfa (medicago sativa), plants were inoculated with ensifer meliloti l33 and azospirillum brasilense sp7 in pot experiments using two different soils separately as well as in a mixture. one soil was contaminated with chemical waste products; the other was an arable soil. soil factors, including availability of macro- and micronutrients as well as carbon and nitrogen contents were found to exhibit a much greater influence o ...201121627671
in vitro interaction between the ammonium transport protein amtb and partially uridylylated forms of the p(ii) protein glnz.the ammonium transport family amt/rh comprises ubiquitous integral membrane proteins that facilitate ammonium movement across biological membranes. besides their role in transport, amt proteins also play a role in sensing the levels of ammonium in the environment, a process that depends on complex formation with cytosolic proteins of the p(ii) family. trimeric p(ii) proteins from a variety of organisms undergo a cycle of reversible posttranslational modification according to the prevailing nitro ...201121645649
surface colonization by azospirillum brasilense sm in the indole-3-acetic acid dependent growth improvement of sorghum.the key to improving plant productivity is successful bacterial-plant interaction in the rhizosphere that can be maintained in the environment. the results presented here confirm azospirillum brasilense strain sm as a competent plant growth promoting bacterium over mid- and long-term associations with sorghum. this study establishes that plant growth can be directly correlated with the associated bacterium's indole-3-acetic acid (iaa) production capability as iaa over-expressing variants, smp30 ...201121656820
a rapid and simple pcr method for identifying isolates of the genus azospirillum within populations of rhizosphere bacteria.aims: to develop a rapid and simple genus-specific polymerase chain reaction (pcr) method for detecting and identifying isolates of the genus azospirillum which is well-recognized as plant growth-promoting rhizobacterium. methods and results: nine pairs of pcr primers were designed based on the azospirillum 16s rrna, ipdc, nifa, and nifh genes to assess their genus specificity by testing against 12 azospirillum (from seven species) and 15 non-azospirillum reference strains, as compared with th ...201121790914
genomic insights into the versatility of the plant growth-promoting bacterium azospirillum amazonense.abstract:201121838888
volatile organic compounds from rhizobacteria increase biosynthesis of essential oils and growth parameters in peppermint (mentha piperita).volatile organic compounds (vocs), characterized by low molecular weight and high vapor pressure, are produced by all organisms as part of normal metabolism, and play important roles in communication within and between organisms. we examined the effects of vocs released by three species of plant growth-promoting rhizobacteria (pseudomonas fluorescens, bacillus subtilis, azospirillum brasilense) on growth parameters and composition of essential oils (eo) in the aromatic plant mentha piperita (pep ...201121843946
the pseudomonas secondary metabolite 2,4-diacetylphloroglucinol is a signal inducing rhizoplane expression of azospirillum genes involved in plant-growth promotion.during evolution, plants have become associated with guilds of plant-growth-promoting rhizobacteria (pgpr), which raises the possibility that individual pgpr populations may have developed mechanisms to cointeract with one another on plant roots. we hypothesize that this has resulted in signaling phenomena between different types of pgpr colonizing the same roots. here, the objective was to determine whether the pseudomonas secondary metabolite 2,4-diacetylphloroglucinol (dapg) can act as a sign ...201121043573
Key physiological properties contributing to rhizosphere adaptation and plant growth promotion abilities of Azospirillum brasilense.Azospirillum brasilense is a plant growth promoting rhizobacterium (PGPR) that is being increasingly used in agriculture in a commercial scale. Recent research has elucidated key properties of A. brasilense that contribute to its ability to adapt to the rhizosphere habitat and to promote plant growth. They include synthesis of the auxin indole-3-acetic acid, nitric oxide, carotenoids, and a range of cell surface components as well as the ability to undergo phenotypic variation. Storage and utili ...201222092983
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