Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
Phylogenetic diversity and symbiotic functioning in mungbean (Vigna radiata L. Wilczek) bradyrhizobia from contrast agro-ecological regions of Nepal.Nepal consists wide range of climatic and topographical variations. Here, we explored the phylogeny of native mungbean bradyrhizobia isolated from different agro-ecological regions of Nepal and accessed their nodulation and nitrogen fixation characteristics. Soil samples were collected from three agro-ecological regions with contrasting climate and topography. A local mungbean cultivar, Kalyan, was used as a trap plant. We characterized isolates based on the full nucleotide sequence of the 16S r ...201222178390
Unique structural features and sequence motifs of proline utilization A (PutA).Proline utilization A proteins (PutAs) are bifunctional enzymes that catalyze the oxidation of proline to glutamate using spatially separated proline dehydrogenase and pyrroline-5-carboxylate dehydrogenase active sites. Here we use the crystal structure of the minimalist PutA from Bradyrhizobium japonicum (BjPutA) along with sequence analysis to identify unique structural features of PutAs. This analysis shows that PutAs have secondary structural elements and domains not found in the related mon ...201222201760
Efficient electricity generation from sewage sludge usingbiocathode microbial fuel cell.Microbial fuel cells (MFCs) with abiotic cathodes require expensive catalyst (such as Pt) or catholyte (such as hexacynoferrate) to facilitate oxidation reactions. This study incorporated biocathodes into a three-chamber MFC to yield electricity from sewage sludge at maximum power output of 13.2±1.7W/m(3) during polarization, much higher than those previously reported. After 15d operation, the total chemical oxygen demand (TCOD) removal and coulombic efficiency (CE) of cell reached 40.8±9.0% and ...201222078254
A Role for Bradyrhizobium japonicum ECF16 Sigma Factor EcfS in the Formation of a Functional Symbiosis with Soybean.Alternative sigma (s) factors, proteins that recruit RNA polymerase core enzyme to target promoters, are one mechanism by which bacteria transcriptionally regulate groups of genes in response to environmental stimuli. A class of s(70) proteins, termed extracytoplasmic function (ECF) s factors, are involved in cellular processes such as bacterial stress responses and virulence. Here, we describe an ECF16 s factor, EcfS (Blr4928) from the gram-negative soil bacterium Bradyrhizobium japonicum USDA1 ...201221879796
mercury-resistant rhizobial bacteria isolated from nodules of leguminous plants growing in high hg-contaminated soils.a survey of symbiotic bacteria from legumes grown in high mercury-contaminated soils (almadén, spain) was performed to produce a collection of rhizobia which could be well adapted to the environmental conditions of this region and be used for restoration practices. nineteen hg-tolerant rhizobia were isolated from nodules of 11 legume species (of the genera medicago, trifolium, vicia, lupinus, phaseolus, and retama) and characterized. based on their growth on hg-supplemented media, the isolates w ...201222246528
[genetic diversity and phylogeny of bradyrhizobia associated with desmodium spp].genetic diversity and phylogeny of bradyrhizobial strains associated with desmodium spp. in subtropic and temperate regions of china were analyzed.201122233051
functional characterization of nopt1 and nopt2, two type iii effectors of bradyrhizobium japonicum.nopt1 and nopt2, putative type iii effectors from the plant symbiotic bacterium bradyrhizobium japonicum, are predicted to belong to a family of yopt/avrpphb effectors, which are cysteine proteases. in the present study, we showed that both nopt1 and nopt2 indeed possess cysteine protease activity. when overexpressed in escherichia coli, both nopt1 and nopt2 undergo autoproteolytic processing which is largely abolished in the presence of e-64, a papain family-specific inhibitor. mutations of nop ...201122112296
comparison of the 'ca. liberibacter asiaticus' genome adapted for an intracellular lifestyle with other members of the rhizobiales.an intracellular plant pathogen 'candidatus liberibacter asiaticus,' a member of the rhizobiales, is related to sinorhizobium meliloti, bradyrhizobium japonicum, nitrogen fixing endosymbionts, agrobacterium tumefaciens, a plant pathogen, and bartonella henselae, an intracellular mammalian pathogen. whole chromosome comparisons identified at least 50 clusters of conserved orthologous genes found on the chromosomes of all five metabolically diverse species. the intracellular pathogens 'ca. liberib ...201121876745
genotypic characterization of phage-typed indigenous soybean bradyrhizobia and their host range symbiotic effectiveness.analysis of genetic diversity among indigenous rhizobia and its symbiotic effectiveness with soybean cultivar is important for development of knowledge about rhizobial ecology. in india, little is known about the genetic resources and diversity of rhizobia nodulating soybean. indigenous bradyrhizobia isolated from root nodules of soybean plants, collected from traditional cultivating regions of two states (madhya pradesh and uttar pradesh) of india, were screened for bacteriophage sensitivity to ...201121984348
photosynthetic bradyrhizobium sp. strain ors285 synthesizes 2-o-methylfucosylated lipochitooligosaccharides for nod gene? dependent interaction with aeschynomene plants.bradyrhizobium sp. strain ors285 is a photosynthetic bacterium that forms nitrogen-fixing nodules on the roots and stems of tropical aquatic legumes of the aeschynomene genus. the symbiotic interaction of bradyrhizobium sp. strain ors285 with certain aeschynomene spp. depends on the presence of nodulation (nod) genes whereas the interaction with other species is nod gene independent. to study the nod gene-dependent molecular dialogue between bradyrhizobium sp. strain ors285 and aeschynomene spp. ...201121864045
the nitric oxide response in plant-associated endosymbiotic bacteria.nitric oxide (no) is a gaseous signalling molecule which becomes very toxic due to its ability to react with multiple cellular targets in biological systems. bacterial cells protect against no through the expression of enzymes that detoxify this molecule by oxidizing it to nitrate or reducing it to nitrous oxide or ammonia. these enzymes are haemoglobins, c-type nitric oxide reductase, flavorubredoxins and the cytochrome c respiratory nitrite reductase. expression of the genes encoding these enz ...201122103544
bacterial outer membrane channel for divalent metal ion acquisition.the prevailing model of bacterial membrane function predicts that the outer membrane is permeable to most small solutes because of pores with limited selectivity based primarily on size. here, we identified mnop in the gram-negative bacterium bradyrhizobium japonicum as a gene coregulated with the inner membrane mn(2+) transporter gene mnth. mnop is an outer membrane protein expressed specifically under manganese limitation. mnop acts as a channel to facilitate the tranlocation of mn(2+), but no ...201121880957
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
[phenotypic and genotypic characterization of twelve rhizobial isolates from different regions of venezuela].rhizobial taxonomy and systematics have progressed substantially, nevertheless, few studies have been developed on venezuelan species. this study evaluated the phenotypic and genetic variation between 12 venezuelan indigenous rhizobial isolates and 10 international referential strains, by phenotypical traits and dna molecular markers. in this regard, a pcr-rflp of the 16s rdna gene, the presence of large plasmids, metabolic assays in solid media, salinity resistance, ph and temperature growth co ...201122017109
Biodegradation of melamine and its hydroxy derivatives by a bacterial consortium containing a novel Nocardioides species.Melamine has recently been recognized as a food contaminant with adverse human health effects. Melamine contamination in some crops arises from soil and water pollution from various causes. To remove melamine from the polluted environment, a novel bacterium, Nocardioides sp. strain ATD6, capable of degrading melamine was enriched and isolated from a paddy soil sample. The enrichment culture was performed by the soil-charcoal perfusion method in the presence of triazine-degrading bacteria previou ...201122105542
nitrate-dependent n₂o emission from intact soybean nodules via denitrification by bradyrhizobium japonicum bacteroids.in the presence of nitrate, n₂o emission increased markedly from soybean roots inoculated with nosz mutant of bradyrhizobium japonicum, but not from soybean roots inoculated with a napa nosz double mutant, indicating that b. japonicum bacteroids in soybean nodules are able to convert the exogenously supplied nitrate into n₂o via a denitrification pathway.201122003029
microvirga lupini sp. nov., microvirga lotononidis sp. nov., and microvirga zambiensis sp. nov. are alphaproteobacterial root nodule bacteria that specifically nodulate and fix nitrogen with geographically and taxonomically separate legume hosts.strains of gram-negative, rod-shaped, non-spore-forming bacteria were isolated from nitrogen-fixing nodules of the native legumes listia angolensis (from zambia) and lupinus texensis (from texas, usa). phylogenetic analysis of the 16s rrna gene showed that the novel strains belong to the genus microvirga, with 96.1 % or greater sequence similarity with type strains of this genus. the closest relative of the representative strains lut6t and wsm3557t was m. flocculans tfbt, with 97.6-98.0 % simila ...201122199210
a unique bicyclic monosaccharide from the bradyrhizobium lipopolysaccharide and its role in the molecular interaction with plants.sugar coat: the nitrogen-fixing soil bacterium bradyrhizobium sp. btai1 is coated with a unique lipopolysaccharide that does not induce innate immune responses in its host plant aeschynomene indica or in different plant families. the chemical nature of the monosaccharide forming the polymer is unprecedented in nature, which helps to avoid "harmful" recognition by its symbiotic host.201122058060
long-term field fertilization alters the diversity of autotrophic bacteria based on the ribulose-1,5-biphosphate carboxylase/oxygenase (rubisco) large-subunit genes in paddy soil.carbon dioxide (co(2)) assimilation by autotrophic bacteria is an important process in the soil carbon cycle with major environmental implications. the long-term impact of fertilizer on co(2) assimilation in the bacterial community of paddy soils remains poorly understood. to narrow this knowledge gap, the composition and abundance of co(2)-assimilating bacteria were investigated using terminal restriction fragment length polymorphism and quantitative pcr of the cbbl gene [that encodes ribulose- ...201122159889
Evolutionary instability of symbiotic function in Bradyrhizobium japonicum.Bacterial mutualists are often acquired from the environment by eukaryotic hosts. However, both theory and empirical work suggest that this bacterial lifestyle is evolutionarily unstable. Bacterial evolution outside of the host is predicted to favor traits that promote an independent lifestyle in the environment at a cost to symbiotic function. Consistent with these predictions, environmentally-acquired bacterial mutualists often lose symbiotic function over evolutionary time. Here, we investiga ...201122073160
whole-genome expression profiling of bradyrhizobium japonicum in response to hydrogen peroxide.bradyrhizobium japonicum, a nitrogen-fixing bacterium in soil, establishes a symbiotic relationship with the leguminous soybean plant. despite a mutualistic association between the two partners, the host plant produces an oxidative burst to protect itself from the invasion of rhizobial cells. we investigated the effects of h(2)o(2)-mediated oxidative stress on b. japonicum gene expression in both prolonged exposure (pe) and fulminant shock (fs) conditions. in total, 439 and 650 genes were differ ...201121864047
bradyrhizobium huanghuaihaiense sp. nov., an effective symbiotic bacterium isolated from soybean (glycine max l.) nodules in northern (huang-huai-hai) plain of china.in a survey of biodiversity and biogeography of rhizobia associated with soybean (glycine max l.) in different sites of northern (huang-huai-hai) plain of china, ten strains were defined as a novel genomic species in the genus of bradyrhizobium. they were distinguished from defined species in rflp (restriction fragment length polymorphism) of 16s rrna gene and intergenic spacer (igs) between 16s and 23s rrna genes. in box-pcr, these strains presented two patterns sharing 94% similarities, demons ...201122003042
early signaling in actinorhizal symbioses.nitrogen-fixing root nodulation, confined to four plant orders, encompasses more than 14,000 leguminosae species, and approximately 200 actinorhizal species forming symbioses with rhizobia (rhizobium, bradyrhizobium, etc) and frankia bacterial species, respectively. while several genetic components of the host-symbiont interaction have been identified in legumes, little is known about the genetic bases of actinorhizal symbiosis. however, we recently demonstrated the existence of common symbiotic ...201121847030
characterization of rhizobia from legumes of agronomic interest grown in semi-arid areas of central spain relates genetic differences to soil properties.a study of symbiotic bacteria from traditional agricultural legumes from central spain was performed to create a collection of rhizobia from soils differing in physicochemical, analytical and/or agroecological properties which could be well-adapted to the environmental conditions of this region, and be used for sustainable agricultural practices. thirty-six isolates were obtained from root-nodules of fifteen legume species (including cicer arietinum, lathyrus sativus, lens culinaris, lupinus spp ...201121953333
2,4,5-trichlorophenol degradation using a novel tio2-coated biofilm carrier: roles of adsorption, photocatalysis, and biodegradation.intimate coupling of photocatalysis and biodegradation (icpb) offers potential for degrading biorecalcitrant and toxic organic compounds. this study reports on a novel sponge-type, tio(2)-coated biofilm carrier that showed significant adherence of tio(2) and ability to accumulate biomass in its interior. this carrier was tested for icpb in a continuous-flow photocatalytic circulating-bed biofilm reactor (pcbbr) to mineralize 2,4,5-trichlorophenol (tcp), which is biorecalcitrant. four mechanisms ...201121861477
diversity of bacteria at healthy human conjunctiva.purpose. ocular surface (os) microbiota contributes to infectious and autoimmune diseases of the eye. comprehensive analysis of microbial diversity at the os has been impossible because of the limitations of conventional cultivation techniques. this pilot study aimed to explore true diversity of human os microbiota using dna sequencing-based detection and identification of bacteria. methods. composition of the bacterial community was characterized using deep sequencing of the 16s rrna gene ampli ...201121571682
stereoselectivity and conformational stability of haloalkane dehalogenase dbja from bradyrhizobium japonicum usda110: the effect of ph and temperature.the effect of ph and temperature on structure, stability, activity and enantioselectivity of haloalkane dehalogenase dbja from bradyrhizobium japonicum usda110 was investigated in this study. conformational changes have been assessed by circular dichroism spectroscopy, functional changes by kinetic analysis, while quaternary structure was studied by gel filtration chromatography. our study shows that the dbja enzyme is highly tolerant to ph changes. its secondary and tertiary structure was not a ...201121635695
characterization of the self-cleaving effector protein nope1 of bradyrhizobium japonicum.nope1 is a type iii-secreted protein of the symbiont bradyrhizobium japonicum which is expressed in nodules. in vitro it exhibits self-cleavage in a duplicated domain of unknown function (duf1521), but only in the presence of calcium. here we show that either domain is self-sufficient for cleavage. an exchange of the aspartic acid residue at the cleavage site with asparagine prevented cleavage, however, cleavage was still observed with glutamic acid at the same position, indicating that a negati ...201121642459
characterization of cyclic ╬▓-glucans of bradyrhizobium by maldi-tof mass spectrometry.periplasmic, cyclic ╬▓-glucans isolated from bradyrhizobium elkanii, bradyrhizobium liaoningense, and bradyrhizobium yuanmingense strains have been investigated by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (maldi-tof ms), 1d and 2d nuclear magnetic resonance (nmr), as well as standard chemical methods. these compounds are built of 10-13 d-glucose residues. the main fractions contain molecules assembled of 12 hexose units (m(w)=1945.363da). glucose mono ...201121665197
the iron responsive regulator irr is required for wild-type expression of the gene encoding the heme transporter bhua in brucella abortus 2308.irr and rira, rather than fur, serve as the major iron-responsive regulators in the a-proteobacteria. with only a few exceptions, however, the relative contributions of these transcriptional regulators to the differential expression of specific iron metabolism genes in brucella strains is unclear. the gene encoding the outer membrane heme transporter bhua exhibits maximum expression in brucella abortus 2308 during growth under iron deprived conditions, and mutational studies indicate that this p ...201121804001
taxonomic and functional assignment of cloned sequences from high andean forest soil metagenome.total metagenomic dna was isolated from high andean forest soil and subjected to taxonomical and functional composition analyses by means of clone library generation and sequencing. the obtained yield of 1.7 µg of dna/g of soil was used to construct a metagenomic library of approximately 20,000 clones (in the plasmid p-bluescript ii sk+) with an average insert size of 4 kb, covering 80 mb of the total metagenomic dna. metagenomic sequences near the plasmid cloning site were sequenced and them tr ...201121792685
biodiversity and biogeography of rhizobia associated with soybean plants grown in the north china plain.as the putative center of origin for soybean and the second largest region of soybean production in china, the north china plain covers temperate and subtropical regions with diverse soil characteristics. however, the soybean rhizobia in this plain have not been sufficiently studied. in order to investigate the biodiversity and biogeography of soybean rhizobia in this plain, a total of 309 isolates of symbiotic bacteria from the soybean nodules collected from 16 sampling sites were studied with ...201121784912
involvement of glutathione and enzymatic defense system against cadmium toxicity in bradyrhizobium sp. strains (peanut symbionts).in this study, the effects of cadmium (cd) on cell morphology and antioxidant enzyme activities as well as the distribution of the metal in different cell compartments in bradyrhizobium sp. strains were investigated. these strains were previously classified as sensitive (bradyrhizobium sp. semia 6144) and tolerant (bradyrhizobium sp. nlh25) to cd. transmission electron micrographs showed large electron-translucent inclusions in the sensitive strain and electron-dense bodies in the tolerant strai ...201121766174
sinorhizobium fredii usda257 and s. fredii usda191, cultivar-specific and non-specific symbionts of soybean, produce distinct cell surface appendages.sinorhizobium fredii usda257 and s. fredii usda191 are fast-growing rhizobia that form nitrogen-fixing nodules on soybean roots. in contrast to usda191, usda257 exhibits cultivar specificity and can form nodules only on primitive soybean cultivars. in response to flavonoids released from soybean roots these two rhizobia secrete nodulation outer proteins (nop) to the extracellular milieu through a type iii secretion system. in spite of the fact that nop proteins are known to regulate legume nodul ...201121764962
characterization of bradyrhizobium species isolated from root nodules of cytisus villosus grown in morocco.from a total of 73 bacterial strains isolated from root nodules of cytisus villosus grown in soils of the central-western region of the moroccan rif, 68 strains clustered into 19 repetitive extragenic palindromic (rep)-polymerase chain reaction (pcr) groups. the nearly complete 16s rrna gene sequence from each strain showed they were closely related to members of the genus bradyrhizobium of the alphaproteobacteria, but affiliation at the species level was not clear. sequencing of the housekeepin ...201121757309
bacterial rubisco is required for efficient bradyrhizobium/aeschynomene symbiosis.rhizobia and legume plants establish symbiotic associations resulting in the formation of organs specialized in nitrogen fixation. in such organs, termed nodules, bacteria differentiate into bacteroids which convert atmospheric nitrogen and supply the plant with organic nitrogen. as a counterpart, bacteroids receive carbon substrates from the plant. this rather simple model of metabolite exchange underlies symbiosis but does not describe the complexity of bacteroids' central metabolism. a previo ...201121750740
symbiotic association between soybean plants and bradyrhizobium japonicum develops oxidative stress and heme oxygenase-1 induction at early stages.we have previously demonstrated that the induction of heme oxygenase-1 (ho-1) (ec 1.14.99.3) plays a protective role against oxidative stress in leaves and nodules of soybean plants subjected to cadmium, uv-b radiation, and salt stress. here, we investigated ho-1, localization and their relationship with oxidative stress in different growth stages of soybean plants roots inoculated with bradyrhizobium japonicum (3, 5, 7, 10, and 20 days post-inoculation) and nodules. after 7 days of inoculation, ...201121722412
rhizobial nod factors are required for cortical cell division in the nodule morphogenetic programme of the aeschynomeneae legume arachis.nod factors are among the best-studied molecules implicated in the signal exchange that leads to legume-rhizobia symbiosis. the role of these molecules in symbiosis development has been primarily studied in legumes invaded through infection threads. in these plants, nod factors generate several responses required for nodulation, including the induction of cortical cell division to form the nodule primordium. arachis hypogaea l. (peanut) exhibits a specific mode of rhizobial infection and nodule ...201121815984
the bradyrhizobium japonicum frcb gene encodes a diheme ferric reductase.iron utilization by bacteria in aerobic environments involves uptake as a ferric chelate from the environment, followed by reduction to the ferrous form. ferric iron reduction is poorly understood in most bacterial species. here, we identified bradyrhizobium japonicum frcb (bll3557) as a gene adjacent to, and coregulated with, the pyor gene (blr3555) encoding the outer membrane receptor for transport of a ferric pyoverdine. frcb is a membrane-bound, diheme protein, characteristic of eukaryotic f ...201121705608
a dual-targeted soybean protein is involved in bradyrhizobium japonicum infection of soybean root hair and cortical cells.the symbiotic interaction between legumes and soil bacteria (e.g., soybean [glycine max l.] and bradyrhizobium japonicum]) leads to the development of a new root organ, the nodule, where bacteria differentiate into bacteroids that fix atmospheric nitrogen for assimilation by the plant host. in exchange, the host plant provides a steady carbon supply to the bacteroids. this carbon can be stored within the bacteroids in the form of poly-3-hydroxybutyrate granules. the formation of this symbiosis r ...201121815830
phenotypic and phylogenetic characterization of native peanut bradyrhizobium isolates obtained from c+¦rdoba, argentina.peanut is an economically important legume nodulated by slow-growing bacteria of the genus bradyrhizobium. in this study, a collection of native slow-growing peanut rhizobial isolates from argentina was obtained and characterized. the phenotypical characterization included the determination of the symbiotic properties, whereas the genetic and phylogenetic diversity was assessed through eric-pcr and sequencing of the internal transcribed spacer (its) region, as well as the dnak and noda genes. th ...201121742454
biotechnological conversion of glycerol to 2-amino-1,3-propanediol (serinol) in recombinant escherichia coli.microbial conversion is an important technology for the refinement of renewable resources. here, we describe the biotechnological conversion of glycerol to 2-amino-1,3-propanediol (serinol), a relevant intermediate in several chemical syntheses processes. either the dihydroxyacetone phosphate aminotransferase/dihydrorhizobitoxine synthase (rtxa) of bradyrhizobium elkanii usd94 or only the n-terminal domain (rtxa513) comprising the first reaction, respectively, was expressed in recombinant escher ...201121706173
phylogenetic analysis reveals gene conversions in multigene families of rhizobia.gene families are an important and intrinsic trait of rhizobial species. these gene copies can participate in non-reciprocal recombination events, also called gene conversions. gene conversion has diverse roles, but it is usually implicated in the evolution of multigene families. here, we searched for gene conversions in multigene families of six representative rhizobial genomes. we identified 11 gene families with different numbers of copies, genome location and function in cfn42 and ciat652 st ...201121823087
nodulation of aeschynomene afraspera and a. indica by photosynthetic bradyrhizobium sp. strain ors285: the nod-dependent versus the nod-independent symbiotic interaction.here, we present a comparative analysis of the nodulation processes of aeschynomene afraspera and a. indica that differ in their requirement for nod factors (nf) to initiate symbiosis with photosynthetic bradyrhizobia. the infection process and nodule organogenesis was examined using the green fluorescent protein-labeled bradyrhizobium sp. strain ors285 able to nodulate both species. in a. indica, when the nf-independent strategy is used, bacteria penetrated the root intercellularly between axil ...201121995799
phylogenetic relationship of lotus uliginosus symbionts with bradyrhizobia nodulating genistoid legumes.lotus species are legumes with potential for pastures in soils with low-fertility and environmental constraints. the aim of this work was to characterize bacteria that establish efficient nitrogen-fixing symbiosis with the forage species lotus uliginosus. a total of 39 isolates were obtained from nodules of l. uliginosus naturally growing in two different locations of portugal. molecular identification of the isolates plus the commercial inoculant strain nzp2039 was performed by rep-pcr, 16s rrn ...201122092879
change in land use alters the diversity and composition of bradyrhizobium communities and led to the introduction of rhizobium etli into the tropical rain forest of los tuxtlas (mexico).nitrogen-fixing bacteria of the bradyrhizobium genus are major symbionts of legume plants in american tropical forests, but little is known about the effects of deforestation and change in land use on their diversity and community structure. forest clearing is followed by cropping of bean (phaseolus vulgaris) and maize as intercropped plants in los tuxtlas tropical forest of mexico. the identity of bean-nodulating rhizobia in this area is not known. using promiscuous trap plants, bradyrhizobia w ...201122109095
proteomics reveals differential expression of proteins related to a variety of metabolic pathways by genistein-induced bradyrhizobium japonicum strains.the rhizobia-legume symbiosis requires a coordinated molecular interaction between the symbionts, initiated by seed and root exudation of several compounds, mainly flavonoids, that trigger the expression of nodulation genes in the bacteria. since the role of flavonoids seems to be broader than the induction of nodulation genes, we aimed at characterizing genistein-induced proteins of bradyrhizobium japonicum cpac 15 (=semia 5079), used in commercial soybean inoculants in brazil, and of two genet ...201122119543
Isovaleryl-homoserine lactone, an unusual branched-chain quorum-sensing signal from the soybean symbiont Bradyrhizobium japonicum.Many species of Proteobacteria communicate by using LuxI-LuxR-type quorum-sensing systems that produce and detect acyl-homoserine lactone (acyl-HSL) signals. Most of the known signals are straight-chain fatty acyl-HSLs, and evidence indicates that LuxI homologs prefer fatty acid-acyl carrier protein (ACP) over fatty acyl-CoA as the acyl substrate for signal synthesis. Two related LuxI homologs, RpaI and BtaI from Rhodopseudomonas palustris and photosynthetic stem-nodulating bradyrhizobia, direct ...201121949379
Denitrification in Sinorhizobium meliloti.Denitrification is the complete reduction of nitrate or nitrite to N2, via the intermediates nitric oxide (NO) and nitrous oxide (N2O), and is coupled to energy conservation and growth under O2-limiting conditions. In Bradyrhizobium japonicum, this process occurs through the action of the napEDABC, nirK, norCBQD and nosRZDFYLX gene products. DNA sequences showing homology with nap, nirK, nor and nos genes have been found in the genome of the symbiotic plasmid pSymA of Sinorhizobium meliloti stra ...201122103545
effect of rj-genotype and cultivation temperature on the community structure of soybean-nodulating bradyrhizobia.the nodulation tendency and community structure of indigenous bradyrhizobia on rj-genotype soybean cultivars at cultivation temperatures of 33/28°c, 28/23°c and 23/18°c, 16/8 h (day/night degrees, hours) were investigated using 780 bradyrhizobial dna samples from an andosol with 13 soybean cultivars of four rj-genotypes (non-rj, rj(2)rj(3), rj(4) and rj(2)rj(3)rj(4)). a dendrogram was constructed based on restriction fragment length polymorphism of the polymerase chain reaction products (pcr-rfl ...201122156423
Development and application of a multilocus sequence analysis method for the identification of genotypes within the genus Bradyrhizobium and for establishing nodule occupancy of soybean (Glycine max L. Merr).A Multilocus Sequence Typing (MLST) method based on allelic variation of 7 chromosomal loci was developed for characterizing genotypes within the genus Bradyrhizobium. With the method 29 distinct multilocus genotypes (GTs) were identified among 190 culture collection soybean strains. The occupancy of 347 nodules taken from uninoculated field-grown soybean plants also was determined. The bacteroid genotypes were either the same or were closely related to genotypes identified among strains in th ...201122074348
evolutionary duplication of lipo-oligochitin-like receptor genes in soybean differentiates their function in cell division and cell invasion.gene duplication in evolution has long been viewed as a mechanism for functional divergence. we recently cloned two related lipo-oligo-chitin receptor genes (gmnfr1+¦ and gmnfr1+¦) in glycine max(soybean) that allowed the distinction of two nodulation factor (nf) responses during early legume nodule ontogeny, namely invasion of the root hair and concomitant cortical cell divisions. root-controlled gmnfr1+¦mutants nod49 and rj1 failed to form curled root hairs, infection threads and nodules but d ...201121389773
straight and branched (?-1)-hydroxylated very long chain fatty acids are components of bradyrhizobium lipid a.lipopolysaccharides of seven bradyrhizobium strains and three whole-cell fatty acid preparations from bacteria isolated from nodules of sarothamnus scoparius (common broom) were studied for the presence of very long chain (?-1)-hydroxy fatty acids. several such fatty acids were identified. among them, straight-chain as well as mono- and dimethyl branched acids with chains in the range from 26 to 34 carbon atoms were found. pyrrolidides and 4,4-dimethyloxazoline derivatives were used to determine ...201121409182
endosymbiotic bacteria nodulating a new endemic lupine lupinus mariae-josephi from alkaline soils in eastern spain represent a new lineage within the bradyrhizobium genus.lupinus mariae-josephi is a recently described endemic lupinus species from a small area in eastern spain where it thrives in soils with active lime and high ph. the l. mariae-josephi root symbionts were shown to be very slow-growing bacteria with different phenotypic and symbiotic characteristics from those of bradyrhizobium strains nodulating other lupinus. their phylogenetic status was examined by multilocus sequence analyses of four housekeeping genes (16s rrna, glnii, reca, and atpd) and sh ...201121420266
a study on the prevalence of bacteria that occupy nodules within single peanut plants.in this study, bacteria hosted in root nodules of single plants of legume arachis hypogaea l. (peanut) cv tegua runner growing at field were isolated. the collection of nodule isolates included both fast and slow growing strains. their genetic diversity was assessed in order to identify the more frequently rhizobial strain associated to nodules from single plants. molecular fingerprinting of 213 nodular isolates indicated heterogeneity, absence of a dominant genotype and, therefore, of a unique ...201121442391
origins of aging mass loss in recombinant n-terminus and c-terminus deletion mutants of the heme-pas biosensor domain bjfixlh(140-270).nine recombinant fixl heme domains from bradyrhizobium japonicum previously were shown to exhibit mass instability independent of many environmental factors (j.d. satterlee, c. suquet, a. bidwai, j. erman, l. schwall, r. jimenez, biochemistry 47 (2008) 1540-1553). two of those recombinant proteins were produced in remote laboratories. mass losses begin appearing at completion of isolation and comprise a substantial proportion of samples within 1-3 days of storage and handling. thus, degradation ...201121443850
symbiotic properties and first analyses of the genomic sequence of the fast growing model strain sinorhizobium fredii hh103 nodulating soybean.glycine max (soybean) plants can be nodulated by fast-growing rhizobial strains of the genus sinorhizobium as well as by slow-growing strains clustered in the genus bradyrhizobium. fast-growing rhizobia strains with different soybean cultivar specificities have been isolated from chinese soils and from other geographical regions. most of these strains have been clustered into the species sinorhizobium fredii. the s. fredii strain hh103 was isolated from soils of hubei province, central china and ...201121458507
analysis of the role of the two flagella of bradyrhizobium japonicum in competition for nodulation of soybean.bradyrhizobium japonicum has two types of flagella. one has thin filaments consisting of the 33-kda flagellins flici and flicii (flici-ii) and the other has thick filaments consisting of the 65-kda flagellins flic1, flic2, flic3, and flic4 (flic1-4). to investigate the roles of each flagellum in competition for nodulation, we obtained mutants deleted in flici-ii and/or flic1-4 in the genomic backgrounds of two derivatives from the reference strain usda 110: the streptomycin-resistant derivative ...201121470300
aryl-homoserine lactone quorum sensing in stem-nodulating photosynthetic bradyrhizobia.many proteobacteria possess luxi-luxr-type quorum-sensing systems that produce and detect fatty acyl-homoserine lactone (hsl) signals. the photoheterotroph rhodopseudomonas palustris is unusual in that it produces and detects an aryl-hsl, p-coumaroyl-hsl, and signal production requires an exogenous source of p-coumarate. a photosynthetic stem-nodulating member of the genus bradyrhizobium produces a small molecule signal that elicits an r. palustris quorum-sensing response. here, we show that thi ...201121471459
anaplerotic function of phosphoenolpyruvate carboxylase in bradyrhizobium japonicum usda110.in bacteria, anaplerotic carbon fixation necessary for growth on carbon sources that are metabolized to three-carbon intermediates is provided by the activity of pyruvate carboxylase (pyc) and/or phosphoenolpyruvate carboxylase (ppc). in contrast to other rhizobia, which encode only one of these enzymes in their genomes, bradyrhizobium japonicum usda110 encodes both. streptavidin-hrp western blot analysis of b. japonicum extracts demonstrated the presence of a biotin-containing protein whose mol ...201121479798
heme binding to the second, lower-affinity site of the global iron regulator irr from rhizobium leguminosarum promotes oligomerization.the iron responsive regulator irr is found in a wide range of α-proteobacteria, where it regulates many genes in response to the essential but toxic metal iron. unlike fur, the transcriptional regulator that is used for iron homeostasis by almost all other bacterial lineages, irr does not sense fe(2+) directly, but, rather, interacts with a physiologically important form of iron, namely heme. recent studies of irr from the n(2) -fixing symbiont rhizobium leguminosarum (irr(rl) ) showed that it b ...201121481185
visualization and direct counting of individual denitrifying bacterial cells in soil by nirk-targeted direct in situ pcr.the abundance of denitrifying bacteria in soil has been determined primarily by the conventional most probable number (mpn) method. we have developed a single-cell identification technique that is culture-independent, direct in situ pcr, to enumerate denitrifying bacteria in soils. the specificity of this method was evaluated with six species of denitrifying bacteria using nirk as the target gene; escherichia coli was used as a negative control. almost all (97.3%-100%) of the nirk-type denitrify ...201121487206
phylogeny of bradyrhizobia from chinese cowpea miscellany inferred from 16s rrna, atpd, glnii, and 16s-23s intergenic spacer sequences.the cowpea (vigna unguiculata l.), peanut (arachis hypogaea l.), and mung bean (vigna radiata l.) belong to a group of plants known as the "cowpea miscellany" plants, which are widely cultivated throughout the tropic and subtropical zones of africa and asia. however, the phylogeny of the rhizobial strains that nodulate these plants is poorly understood. previous studies have isolated a diversity of rhizobial strains from cowpea miscellany hosts and have suggested that, phylogenetically, they are ...201121491983
synergistic interactions between glomus mosseae and bradyrhizobium japonicum in enhancing proton release from nodules and hyphae.soybean (glycine max l. merr.) seedlings were inoculated with glomus mosseae (gm) and bradyrhizobium japonicum (bj) together or separately to study the effect of interactions on net h(+) effluxes of nodules or extraradical hyphae by in vivo vibrating electrode techniques. gm promoted three-fold the h(+) effluxes of nodules on mycorrhizal lateral roots and bj increased eight-fold the net h(+) effluxes of hyphae developing in the vicinity of nodules on lateral roots. increments in plant p content ...201121494823
molecular diversity and phylogeny of rhizobia associated with lablab purpureus (linn.) grown in southern china.as an introduced plant, lablab purpureus serves as a vegetable, herbal medicine, forage and green manure in china. in order to investigate the diversity of rhizobia associated with this plant, a total of 49 rhizobial strains isolated from ten provinces of southern china were analyzed in the present study with restriction fragment length polymorphism and/or sequence analyses of housekeeping genes (16s rrna, igs, atpd, glnii and reca) and symbiotic genes (nifh and nodc). the results defined the l. ...201121498018
phylogenetic diversity of indigenous cowpea bradyrhizobia from soils in japan based on sequence analysis of the 16s-23s rrna internal transcribed spacer (its) region.cowpea [vigna unguiculata (l.) walp.] is an important legume crop and yet its rhizobia have not been well characterized in many areas. in the present study, sequence analysis of the bacterial 16s-23s rrna internal transcribed spacer (its) region was performed to characterize genetically 76 indigenous cowpea rhizobia from five different geographic regions (okinawa, miyazaki, kyoto, fukushima and hokkaido) of japan. the sequence analysis clustered all isolates in the genus bradyrhizobium. they wer ...201121498019
molecular and biochemical characterization of the 5-nitroanthranilic acid degradation pathway in bradyrhizobium sp. strain js329.biodegradation pathways of synthetic nitroaromatic compounds and anilines are well documented, but little is known about those of nitroanilines. we previously reported that the initial step in 5-nitroanthranilic acid (5naa) degradation by bradyrhizobium sp. strain js329 is a hydrolytic deamination to form 5-nitrosalicylic acid (5nsa), followed by ring fission catalyzed by 5nsa dioxygenase. the mechanism of release of the nitro group was unknown. in this study, we subcloned, sequenced, and expres ...201121498645
genome-wide transcriptional and physiological responses of bradyrhizobium japonicum to paraquat-mediated oxidative stress.the rhizobial bacterium bradyrhizobium japonicum functions as a nitrogen-fixing symbiont of the soybean plant (glycine max). plants are capable of producing an oxidative burst, a rapid proliferation of reactive oxygen species (ros), as a defense mechanism against pathogenic and symbiotic bacteria. therefore, b. japonicum must be able to resist such a defense mechanism to initiate nodulation. in this study, paraquat, a known superoxide radical-inducing agent, was used to investigate this response ...201121498770
characteristics of bacteroids in indeterminate nodules of the leguminous tree leucaena glauca.rhizobia establish symbiosis with legumes. bacteroids in indeterminate nodules of inverted repeat lacking clade (irlc) legumes undergo terminal differentiation caused by nodule-specific cysteine-rich peptides (ncrs). microscopic observations of bacteroids and the detection of ncrs in indeterminate nodules of the non-irlc legume leucaena glauca were performed. a portion of the bacteroids showed moderate cell elongation, loss of membrane integrity, and multiple nucleoids. the symbiosome contained ...201121502734
bradyrhizobium canariense and bradyrhizobium japonicum are the two dominant rhizobium species in root nodules of lupin and serradella plants growing in europe.forty three bradyrhizobium strains isolated in poland from root nodules of lupin species (lupinus albus, l. angustifolius and l. luteus), and pink serradella (ornithopus sativus) were examined based on phylogenetic analyses of three housekeeping (atpd, glnii and reca) and nodulation (noda) gene sequences. additionally, seven strains originating from root-nodules of yellow serradella (o. compressus) from asinara island (italy) were included in this study. phylogenetic trees revealed that 15 serra ...201121514760
growth temperature and salinity impact fatty acid composition and degree of unsaturation in peanut-nodulating rhizobia.growth and survival of bacteria depend on homeostasis of membrane lipids, and the capacity to adjust lipid composition to adapt to various environmental stresses. membrane fluidity is regulated in part by the ratio of unsaturated to saturated fatty acids present in membrane lipids. here, we studied the effects of high growth temperature and salinity (nacl) stress, separately or in combination, on fatty acids composition and de novo synthesis in two peanut-nodulating bradyrhizobium strains (fast- ...201121523564
genetic diversity of symbiotic bradyrhizobium elkanii populations recovered from inoculated and non-inoculated acacia mangium field trials in brazil.acacia mangium is a legume tree native to australasia. since the eighties, it has been introduced into many tropical countries, especially in a context of industrial plantations. many field trials have been set up to test the effects of controlled inoculation with selected symbiotic bacteria versus natural colonization with indigenous strains. in the introduction areas, a. mangium trees spontaneously nodulate with local and often ineffective bacteria. when inoculated, the persistence of inoculan ...201121531520
perturbation of an arctic soil microbial community by metal nanoparticles.technological advances allowing routine nanoparticle (np) manufacture have enabled their use in electronic equipment, foods, clothing and medical devices. although some nps have antibacterial activity, little is known about their environmental impact and there is no information on the influence of nps on soil in the possibly vulnerable ecosystems of polar regions. the potential toxicity of 0.066% silver, copper or silica nps on a high latitude (>78°n) soil was determined using community level ph ...201121546158
substrate specificity of haloalkane dehalogenases.an enzyme's substrate specificity is one of its most important characteristics. the quantitative comparison of broad-specificity enzymes requires the selection of a homogenous set of substrates for experimental testing, determination of substrate-specificity data and analysis using multivariate statistics. we describe a systematic analysis of the substrate specificities of nine wild-type and four engineered haloalkane dehalogenases. the enzymes were characterized experimentally using a set of 30 ...201121294712
genetic diversity of nodulating and non-nodulating rhizobia associated with wild soybean (glycine soja sieb. & zucc.) in different ecoregions of china.a total of 99 bacterial isolates that originated from root nodules of glycine soja were characterized with restriction analyses of amplified 16s ribosomal dna and 16s-23s rdna intergenic spacers (its), and sequence analyses of 16s rrna, rpob, atpd, reca and nodc genes. when tested for nodulation of g. soja, 72 of the isolates were effective symbionts, and these belonged to five species: bradyrhizobium japonicum, bradyrhizobium elkanii, bradyrhizobium yuanmingense, bradyrhizobium liaoningense and ...201121303397
phairyred: a novel binary vector containing the dsred2 reporter gene for visual selection of transgenic hairy roots.we developed a new plant transformation vector, phairyred, for enabling high throughput, non-destructive selection of agrobacterium rhizogenes-mediated 'hairy-root' transformation. phairyred allows easy in planta visualization of transgenic tissue with minimal disturbance to the plant. the dsred2 reporter gene, encoding a red fluorescent protein, was cloned to yield phairyred (harbouring a multiple cloning site), which was used with the highly efficient k599 a. rhizogenes strain to infect soybea ...201121324970
molecular structure and gene analysis of ce3+ -induced methanol dehydrogenase of bradyrhizobium sp. maff211645.the molecular structure and nucleotide sequence of ce(3+)-induced methanol dehydrogenase (mdh) of bradyrhizobium sp. maff211645 were investigated. the addition of 30 µm ce(3+) to 1/10 nutrient broth containing 0.5% methanol remarkably increased mdh activity. furthermore, la(3+) increased mdh activity, but other heavier rare earth and metal elements did not have the same effect. mdh increased by ce(3+) was purified by sequential column chromatography, and the purified mdh migrated as a single ban ...201121334970
glyceollin, a soybean phytoalexin with medicinal properties.this review covers the biosynthesis of glyceollin and its biological activities including antiproliferative/antitumor action (toward b16 melanoma cells, lncap prostate cancer cells, and bg-1 ovarian cancer cells), anti-estrogenic action (through estrogen receptors a- and ß-), antibacterial action (toward erwinia carotovora, escherichia coli, bradyrhizobium japonicum, sinorhizobium fredii ), antinematode activity, and antifungal activity (toward fusarium solani, phakospora pachyrhizi, diaporthe p ...201121336922
diversity and biogeography of rhizobia isolated from root nodules of glycine max grown in hebei province, china.a total of 215 rhizobial strains were isolated and analyzed with 16s rrna gene, 16s-23s intergenic spacer, housekeeping genes atpd, reca, and glnii, and symbiotic genes nifh and nodc to understand the genetic diversity of soybean rhizobia in hebei province, china. all the strains except one were symbiotic bacteria classified into nine genospecies in the genera of bradyrhizobium and sinorhizobium. surveys on the distribution of these rhizobia in different regions showed that bradyrhizobium japoni ...201121340735
phylogeny of nodulation and nitrogen-fixation genes in bradyrhizobium: supporting evidences for the theory of monophyletic origin and spread and maintenance by both horizontal and vertical transfer.bacteria belonging to the genus bradyrhizobium are capable of establishing symbiotic relationships with a broad range of plants belonging to the three subfamilies of the leguminosae (=fabaceae) family, with the formation of specialized structures on the roots, the nodules, where fixation of atmospheric nitrogen takes place. the symbiosis is under the control of a finely tuned expression of common and host-specific nodulation genes and also of genes related to the assembly and activity of the nit ...201121357454
effect of pesticides on plant growth promoting traits of greengram-symbiont, bradyrhizobium sp. strain mrm6.the aim of this study was to investigate the toxicity of herbicides (metribuzin and glyphosate), insecticides (imidacloprid and thiamethoxam) and fungicides (hexaconazole, metalaxyl and kitazin) at the recommended and the higher dose rates on plant growth promoting activities of bradyrhizobium sp. under in vitro conditions. the bradyrhizobium sp. strain mrm6 was isolated from nodules of greengram plants. pesticide-concentration dependent progressive-decline was observed in plant growth promoting ...201121359648
does a facultative mutualism limit species range expansion?the availability and quality of mutualists beyond a species' range edge may limit range expansion. with the legume chamaecrista fasciculata, we asked to what extent the availability and quality of rhizobia beyond the range edge limits host range expansion. we tested the effect of rhizobia availability on plant growth by transplanting seed from three locations into five sites spanning c. fasciculata's range (interior, at the northern and western range edges, and beyond the range edges), and inocu ...201121380848
expression and functional roles of bradyrhizobium japonicum genes involved in the utilization of inorganic and organic sulfur compounds in free-living and symbiotic conditions.strains of bradyrhizobium spp. form nitrogen-fixing symbioses with many legumes, including soybean. although inorganic sulfur is preferred by bacteria in laboratory conditions, sulfur in agricultural soil is mainly present as sulfonates and sulfur esters. here, we show that bradyrhizobium japonicum and b. elkanii strains were able to utilize sulfate, cysteine, sulfonates, and sulfur-ester compounds as sole sulfur sources for growth. expression and functional analysis revealed that two sets of ge ...201121190435
unusual heme binding in the bacterial iron response regulator protein: spectral characterization of heme binding to the heme regulatory motif.we characterized heme binding in the bacterial iron response regulator (irr) protein, which is a simple heme-regulated protein having a single "heme-regulatory motif", hrm, and plays a key role in the iron homeostasis of a nitrogen-fixing bacterium. the heme titration to wild-type and mutant irr clearly showed that irr has two heme binding sites: one of the heme binding sites is in the hrm, where (29)cys is the axial ligand, and the other one, the secondary heme binding site, is located outside ...201121192735
inoculation- and nitrate-induced cle peptides of soybean control nark-dependent nodule formation.systemic autoregulation of nodulation in legumes involves a root-derived signal (q) that is perceived by a clavata1-like leucine-rich repeat receptor kinase (e.g. gmnark). perception of q triggers the production of a shoot-derived inhibitor that prevents further nodule development. we have identified three candidate cle peptide-encoding genes (gmric1, gmric2, and gmnic1) in soybean (glycine max) that respond to bradyrhizobium japonicum inoculation or nitrate treatment. ectopic overexpression of ...201121198362
bradyrhizobium cytisi sp. nov. isolated from effective nodules of cytisus villosus in morocco.several strains isolated from cytisus villosus nodules have been characterized on the basis of diverse genetic, phenotypic and symbiotic approaches. according to their 16s rrna genes they formed a group closely related to bradyrhizobium canariense bta-1(t) with 99.4% identity. the analysis of three housekeeping genes reca, atpd and glnii, suggested that the c. villosus strains represent a new bradyrhizobium species whose closest relative is also b. canariense bta-1(t) with 94.2, 96.7 and 94.5% i ...201121257682
emerging complexity in the denitrification regulatory network of bradyrhizobium japonicum.bradyrhizobium japonicum is a gram-negative soil bacterium symbiotically associated with soya bean plants, which is also able to denitrify under free-living and symbiotic conditions. in b. japonicum, the napedabc, nirk, norcbqd and nosrzdyflx genes which encode reductases for nitrate, nitrite, nitric oxide and nitrous oxide respectively are required for denitrification. similar to many other denitrifiers, expression of denitrification genes in b. japonicum requires both oxygen limitation and the ...201121265789
genetic characterization of root-nodule bacteria associated with acacia salicina and a. stenophylla (mimosaceae) across south-eastern australia.symbiotic relationships between legumes and nitrogen-fixing soil micro-organisms are of ecological importance in plant communities worldwide. for example, nutrient-poor australian soils are often dominated by shrubby legumes (e.g. species of acacia). however, relatively few studies have quantified patterns of diversity, host-specificity and effectiveness of these ecologically important plant-microbe interactions. in this study, 16s rrna gene sequence and pcr-rflp analyses were used to examine ba ...201120228207
cadmium accumulation and tolerance in bradyrhizobium spp. (peanut microsymbionts).in this study, the effect of cadmium (cd) on cell viability and its accumulation in bradyrhizobium spp. (peanut microsymbionts) as well as the role of glutathione (gsh) in the tolerance to this metal were investigated. a reference strain recommended as peanut inoculant (bradyrhizobium sp. semia6144) grew up to 10 μm cd meanwhile a gsh-deficient mutant strain (bradyrhizobium sp. semia6144-s7z) was unable to grow at this concentration. two native peanut isolates obtained from córdoba soils (bradyr ...201120514484
peroxide stress elicits adaptive changes in bacterial metal ion homeostasis.exposure to hydrogen peroxide (h(2)o(2)) and other reactive oxygen species is a universal feature of life in an aerobic environment. bacteria express enzymes to detoxify h(2)o(2) and to repair the resulting damage, and their synthesis is typically regulated by redox-sensing transcription factors. the best characterized bacterial peroxide-sensors are escherichia coli oxyr and bacillus subtilis perr. analysis of their regulons has revealed that, in addition to inducible detoxification enzymes, ada ...201120977351
improved biohydrogen production with an expression of codon-optimized hemh and lba genes in the chloroplast of chlamydomonas reinhardtii.according to the codon bias in the chloroplast genome of chlamydomonas reinhardtii, the codon-optimized coding regions of both the ferrochelatase gene, hemh, from bradyrhizobium japonicum and the leghemoglobin gene, lba, from glycine max were synthesized de novo and transferred into the chloroplast of c. reinhardtii. the expression level of hemh-lba protein was improved by 6.8 folds in the codon-optimized transgenic alga compared with the non-optimized one under both normal and anaerobic conditi ...201021036035
new evidence for nitrogen fixation within the italian white truffle tuber magnatum.diversity of nitrogen-fixing bacteria and the nitrogen-fixation activity was investigated in tuber magnatum, the most well-known prized species of italian white truffle. degenerate pcr primers were applied to amplify the nitrogenase gene nifh from t. magnatum ascomata at different stages of maturation. putative amino acid sequences revealed mainly the presence of alphaproteobacteria belonging to bradyrhizobium spp. and expression of nifh genes from bradyrhizobia was detected. the nitrogenase act ...201021036337
symbiotic n nutrition, bradyrhizobial biodiversity and photosynthetic functioning of six inoculated promiscuous-nodulating soybean genotypes.six promiscuous soybean genotypes were assessed for their ability to nodulate with indigenous root-nodule bacteria in ghana, with bradyrhizobium japonicum wb74 serving as positive control. although the results revealed free nodulation of all six genotypes in both inoculated and uninoculated plots, there was a marked effect of inoculation on photosynthetic rates and whole-plant c. inoculation also increased stomatal conductance in tgx1485-1d, tgx1448-2e, tgx1740-2f and tgx1445-3e, leading to sign ...201021044808
diagnosis and quantification of glycerol assimilating denitrifying bacteria in an integrated fixed-film activated sludge reactor via 13c dna stable-isotope probing.glycerol, a byproduct of biodiesel and oleo-chemical manufacturing operations, represents an attractive alternate to methanol as a carbon and electron donor for enhanced denitrification. however, unlike methanol, little is known about the diversity and activity of glycerol assimilating bacteria in activated sludge. in this study, the microbial ecology of glycerol assimilating denitrifying bacteria in a sequencing batch integrated fixed film activated sludge (sb-ifas) reactor was investigated usi ...201021053955
whole genome co-expression analysis of soybean cytochrome p450 genes identifies nodulation-specific p450 monooxygenases.cytochrome p450 monooxygenases (p450s) catalyze oxidation of various substrates using oxygen and nad(p)h. plant p450s are involved in the biosynthesis of primary and secondary metabolites performing diverse biological functions. the recent availability of the soybean genome sequence allows us to identify and analyze soybean putative p450s at a genome scale. co-expression analysis using an available soybean microarray and illumina sequencing data provides clues for functional annotation of these ...201021062474
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
glycine max non-nodulation locus rj1: a recombinogenic region encompassing a snp in a lysine motif receptor-like kinase (gmnfr1α).the rj1 mutation of soybean is a simple recessive allele in a single line that arose as a spontaneous mutation in a population; it exhibits non-nodulation with virtually all bradyrhizobium and sinorhizobium strains. here, we described fine genetic and physical mapping of the rj1 locus on soybean chromosome 2. the initial mapping of the rj1 locus using public markers indicated that a343.p2, a sequence-based marker that contains sequence similar to a part of the ljnfr1 gene regulating nodule forma ...201021104396
roles of flavonoids and the transcriptional regulator ttsi in the activation of the type iii secretion system of bradyrhizobium elkanii semia587.bradyrhizobium elkanii semia587 is a symbiotic nitrogen-fixing bacterium of the group commonly called rhizobia, which induce nodule formation in legumes, and is widely used in brazilian commercial inoculants of soybean. in response to flavonoid compounds released by plant roots, besides nod factors, other molecular signals are secreted by rhizobia, such as proteins secreted by type iii secretion systems (t3sss). rhizobial t3sss are activated by the transcription regulator ttsi, which binds to se ...201021109563
bradyrhizobium lablabi sp. nov., isolated from effective nodules of lablab purpureus and arachis hypogaea grown in southern china.five strains isolated from root nodules of lablab purpureus and arachis hypogaea grown in anhui and sichuan provinces of china were classified within the genus bradyrhizobium. these strains had identical 16s rrna nucleotide sequences which shared 99.22% and 99.48% similarities with the most related strains of bradyrhizobium jicamae pac 68(t), bradyrhizobium pachyrhizi pac 48(t) and bradyrhizobium elkanii usda 76(t). polyphasic approaches including 16s rrna gene rflp, igs-rflp, box-pcr, comparati ...201021112989
Refresh
firstprev
12345678910...
nextlast
Displaying items 1 - 100 of 1519