characteristics of rhizobium tianshanense sp. nov., a moderately and slowly growing root nodule bacterium isolated from an arid saline environment in xinjiang, people's republic of china.we performed a numerical analysis of 148 phenotypic characteristics of 20 strains of root nodule bacteria isolated from an arid saline desert soil in the xinjiang region of northwestern people's republic of china and compared these organisms with 28 rhizobium and bradyrhizobium strains obtained from different regions of the people's republic of china and from other countries, including nine type strains of different species. all of the strains examined clustered into two groups at a similarity l ...19957857795
phylogenetic and genetic relationships of mesorhizobium tianshanense and related rhizobia.the genetic and phylogenetic relationships for strains of mesorhizobium tianshanense and its relatives were compared by an analysis of the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) of whole-cell proteins, dna-dna hybridization, and full 16s rrna gene sequencing. the strains of m. tianshanense formed a cluster which was distinct from those of other rhizobium species in the clustering analysis of sds-page. dna-dna relatedness between a-1bs (type strain of m. t ...19979226921
analysis of cellular fatty acids and phenotypic relationships of agrobacterium, bradyrhizobium, mesorhizobium, rhizobium and sinorhizobium species using the sherlock microbial identification system.previous studies have demonstrated that cellular fatty acid analysis is a useful tool for identifying unknown strains of rhizobia and establishing taxonomic relationships between the species. in this study, the fatty acid profiles of over 600 strains belonging to the genera agrobacterium, bradyrhizobium, mesorhizobium, rhizobium and sinorhizobium were evaluated using the gaschromatography-based sherlock microbial identification system (mis). data collected with the mis showed that the three phyl ...200010758890
occurrence and taxonomic significance of oxo-fatty acids in lipopolysaccharides from members of mesorhizobium.lipopolysaccharides (lpss) isolated from seven strains of mesorhizobium were studied for the presence of fatty acids with particular attention for 27-oxooctacosanoic acid and 4-oxo fatty acids. the lpss from all analysed strains contained various amounts of 27-oxo-28:0 and all of them, with the exception of mesorhizobium tianshanense, contained also 4-oxo fatty acids (4-oxo-20:0, 4-oxo-i-21:0, 4-oxo-22:0). the group of amide-linked fatty acids consisted of a wide range of 3-hydroxylated and 4-ox ...200010930069
mesorhizobium septentrionale sp. nov. and mesorhizobium temperatum sp. nov., isolated from astragalus adsurgens growing in the northern regions of china.ninety-five rhizobial strains isolated from astragalus adsurgens growing in the northern regions of china were classified into three main groups, candidate species i, ii and iii, based on a polyphasic approach. comparative analysis of full-length 16s rrna gene sequences of representative strains showed that candidate species i and ii were mesorhizobium, while candidate species iii, which consisted of non-nodulating strains, was closely related to agrobacterium tumefaciens. the phylogenetic relat ...200415545425
a luxr/luxi-type quorum-sensing system in a plant bacterium, mesorhizobium tianshanense, controls symbiotic nodulation.the ability of rhizobia to symbiotically fix nitrogen from the atmosphere when forming nodules on their plant hosts requires various signal transduction pathways. luxr-luxi-type quorum-sensing systems have been shown to be one of the players in a number of rhizobium species. in this study, we found that mesorhizobium tianshanense, a moderate-growth rhizobium that forms nodules on a number of licorice plants, produces multiple n-acyl homoserine lactone (ahl)-like molecules. a simple screen for ah ...200616484206
strains of mesorhizobium amorphae and mesorhizobium tianshanense, carrying symbiotic genes of common chickpea endosymbiotic species, constitute a novel biovar (ciceri) capable of nodulating cicer identify several strains of mesorhizobium amorphae and mesorhizobium tianshanense nodulating cicer arietinum in spain and portugal, and to study the symbiotic genes carried by these strains.200717397480
different mesorhizobium species sharing the same symbiotic genes nodulate the shrub legume anagyris latifolia.the isolation and characterization of six rhizobial strains isolated from anagyris latifolia, a shrub legume endemic to the canary islands, is reported in this study. the isolates were characterized by 16s-ardra, and sequencing of the ribosomal 16srrna gene, the 16s-23srdna intergenic spacer region, and the housekeeping gene for glutamine synthetase ii (glnii). the phylogenies based on the three types of sequences matched, showing that the isolates belonged to three distinct lineages within the ...200717720348
exopolysaccharide biosynthesis is important for mesorhizobium tianshanense: plant host interaction.mesorhizobium tianshanense is a nitrogen-fixing bacterium that can establish symbiotic associations with glycyrrhiza uralensis in the form of root nodules. nodule formation in rhizobia often requires various secreted carbohydrates. to investigate exopolysaccharide (eps) production and function in m. tianshanense, we performed a genome-wide screen using transposon mutagenesis to identify genes involved in eps production. we identified seven mutants that produced significantly lower amounts of eps ...200818188540
different mesorhizobium species associated with caragana carry similar symbiotic genes and have common host ranges.fourteen strains representing 11 caragana-nodulating mesorhizobium genomic species were identified as representing mesorhizobium amorphae, mesorhizobium huakuii, mesorhizobium septentrionale and groups related to mesorhizobium plurifarium, mesorhizobium temperatum, mesorhizobium tianshanense and mesorhizobium mediterraneum by sequencing of the 16s rrna gene, 16s-23s internal transcribed spacer, partial housekeeping reca gene, and previously performed sodium dodecyl sulfate polyacrylamide gel ele ...200818422620
the luxr family quorum-sensing activator mrtr requires its cognate autoinducer for dimerization and activation but not for protein folding.mrtr, a luxr homolog in mesorhizobium tianshanense, is important for symbiosis. we found that mrtr requires its cognate n-acylhomoserine lactone for forming dimers, binding to a single dna site and activating the downstream promoter. however, mrtr is able to fold independently of its ligand.200918978063
mesorhizobium gobiense sp. nov. and mesorhizobium tarimense sp. nov., isolated from wild legumes growing in desert soils of xinjiang, china.twenty-four mesorhizobium strains were isolated from desert soils in the xinjiang region of china and were characterized by a polyphasic approach. these strains grouped into three clusters in igs-rflp, sds-page analysis of whole-cell proteins and box-pcr analysis, corresponding to genomic species v, vi and vii as found in a previous study. the results were supported by sequencing analyses of rrs, igs, atpd and reca genes. genospecies vii was most related to mesorhizobium septentrionale, while ge ...200818984702
mesorhizobium caraganae sp. nov., a novel rhizobial species nodulated with caragana spp. in china.five rhizobial strains representing the largest group in the genus mesorhizobium associated with caragana spp. in china were characterized taxonomically. phylogenetic analysis based on 16s rrna gene sequences indicated that these microsymbionts belonged to the genus mesorhizobium, with mesorhizobium tianshanense usda 3592(t), mesorhizobium temperatum sdw018(t) and mesorhizobium mediterraneum upm-ca36(t) as the closest neighbours (>/=99.5 % 16s rrna gene sequence similarity). genotypic fingerprin ...200818984708
genetic diversity and host range of rhizobia nodulating lotus tenuis in typical soils of the salado river basin (argentina).a total of 103 root nodule isolates were used to estimate the diversity of bacteria nodulating lotus tenuis in typical soils of the salado river basin. a high level of genetic diversity was revealed by repetitive extragenic palindromic pcr, and 77 isolates with unique genomic fingerprints were further differentiated into two clusters, clusters a and b, after 16s rrna restriction fragment length polymorphism analysis. cluster a strains appeared to be related to the genus mesorhizobium, whereas cl ...200919074602
complex quorum-sensing regulatory systems regulate bacterial growth and symbiotic nodulation in mesorhizobium tianshanense.luxr/luxi-type quorum-sensing systems have been shown to be important for symbiotic interactions between a number of rhizobium species and host legumes. in this study, we found that different isolates of mesorhizobium tianshanense, a moderately-growing rhizobium that forms nodules on a number of types of licorice plants, produces several different n-acyl homoserine lactone-like molecules. in m. tianshanense ccbau060a, we performed a genetic screen and identified a network of regulatory component ...200919115053
mesorhizobium metallidurans sp. nov., a metal-resistant symbiont of anthyllis vulneraria growing on metallicolous soil in languedoc, france.a polyphasic taxonomic approach was used to characterize 31 rhizobial isolates obtained from anthyllis vulneraria, a metallicolous legume species, growing close to a zinc mine in the south of france (saint laurent le minier). comparative analysis of nearly full-length 16s rrna gene sequences showed that these gram-negative bacteria belonged to the genus mesorhizobium and that they were related most closely to mesorhizobium tianshanense ors 2640(t). the phylogenetic relationships of these isolate ...200919329619
host legume-exuded antimetabolites optimize the symbiotic rhizosphere.rhizobia form symbiotic nodules on host legumes and fix nitrogen for their hosts in exchange for nutrients. in order to establish this mutually beneficial relationship, rhizobia must compete with other soil bacteria in the host legume rhizosphere to colonize plant roots efficiently. a promoter-trap transposon screen in mesorhizobium tianshanense, a rhizobium that forms nodules on licorice (glycyrrhiza uralensis) plants revealed that the expression of msia, which encodes a putative exporter prote ...200919602148
identification of the quorum-sensing target dna sequence and n-acyl homoserine lactone responsiveness of the brucella abortus virb promoter.vjbr is a luxr-type quorum-sensing (qs) regulator that plays an essential role in the virulence of the intracellular facultative pathogen brucella, the causative agent of brucellosis. it was previously described that vjbr regulates a diverse group of genes, including the virb operon. the latter codes for a type iv secretion system (t4ss) that is central for the pathogenesis of brucella. although the regulatory role of vjbr on the virb promoter (p(virb)) was extensively studied by different group ...201020400542
characterization of strains unlike mesorhizobium loti that nodulate lotus spp. in saline soils of granada, spain.lotus species are forage legumes with potential as pastures in low-fertility and environmentally constrained soils, owing to their high persistence and yield under those conditions. the aim of this work was the characterization of phenetic and genetic diversity of salt-tolerant bacteria able to establish efficient symbiosis with lotus spp. a total of 180 isolates able to nodulate lotus corniculatus and lotus tenuis from two locations in granada, spain, were characterized. molecular identificatio ...201020435777
nodule morphology, symbiotic specificity and association with unusual rhizobia are distinguishing features of the genus listia within the southern african crotalarioid clade lotononis s.l.the legume clade lotononis sensu lato (s.l.; tribe crotalarieae) comprises three genera: listia, leobordea and lotononis sensu stricto (s.s.). listia species are symbiotically specific and form lupinoid nodules with rhizobial species of methylobacterium and microvirga. this work investigated whether these symbiotic traits were confined to listia by determining the ability of rhizobial strains isolated from species of lotononis s.l. to nodulate listia, leobordea and lotononis s.s. hosts and by ex ...201323712451
evolution and taxonomy of native mesorhizobia nodulating medicinal glycyrrhiza species in china.previously, 159 bacterial strains were isolated from the root nodules of wild perennial glycyrrhiza legume species grown on 40 sites in central and north-western china, in which 57 strains were classified as "true symbionts" belonging to the genus mesorhizobium based on amplified fragment length polymorphism (aflp) genomic fingerprinting and partial sequences of the 16s rrna gene [20]. in the present work, the phylogeny of glycyrrhiza nodulating mesorhizobia was further examined by multilocus se ...201627105685
genetic diversity and distribution of rhizobia associated with the medicinal legumes astragalus spp. and hedysarum polybotrys in agricultural soils.with the increasing cultivation of medicinal legumes in agricultural fields, the rhizobia associated with these plants are facing new stresses, mainly from fertilization and irrigation. in this study, investigations on the nodulation of three cultivated medicinal legumes, astragalus mongholicus, astragalus membranaceus and hedysarum polybotrys were performed. bacterial isolates from root nodules of these legumes were subjected to genetic diversity and multilocus sequence analyses. in addition, t ...201626915496
function of msir on canavanine-mediated repression in mesorhizobium tianshanense.mesorhizobium tianshanense employs msia as canavanine exporter, which is upregulated by msir, to successfully form a symbiosis with the legume glycyrrhiza uralensis. in this research, through gel-shift and bacterial two-hybrid examination, msir was found to spontaneously form dimers and bind to msia promoter without additional canavanine. six truncated forms of msir were constructed, and the conserved helix-turn-helix (hth), substrate-binding, and surface-loop domains were found essential for ms ...201525854984
flagellar-dependent motility in mesorhizobium tianshanense is involved in the early stage of plant host interaction: study of an flge mutant.bacterial motility is most likely a critical factor for rhizobium to chemotactically colonize on the root surface prior to infecting leguminous plant hosts. several studies of the rhizobium flagellar filament have been reported, but little is known about the rhizobium flagellum hook. to investigate the roles of the hook protein in flagellum synthesis in mesorhizobium tianshanense, the hook protein-encoding gene flge of m. tianshanense was amplified by pcr and sequenced. comparison of the deduced ...201525287045
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