Derivatives of Rhizobium meliloti strains carrying a plasmid of Rhizobium leguminosarum specifying hydrogen uptake and pea-specific symbiotic functions

1985 ◽  
Vol 140 (4) ◽  
pp. 352-357 ◽  
Author(s):  
R. M. Behki ◽  
G. Selvaraj ◽  
V. N. Iyer
Keyword(s):  
Rhizobium Leguminosarum ◽  
Rhizobium Meliloti ◽  
Hydrogen Uptake ◽  
Derivatives Of

Slow rehydration improves the recovery of dried bacterial populations

1992 ◽  
Vol 38 (6) ◽  
pp. 520-525 ◽  
Author(s):  
J. W. Kosanke ◽  
R. M. Osburn ◽  
G. I. Shuppe ◽  
R. S. Smith
Keyword(s):  
Relative Humidity ◽  
Rhizobium Leguminosarum ◽  
Moisture Absorption ◽  
Rhizobium Meliloti ◽  
Bacterial Populations ◽  
Bulk Powder ◽  
Alfalfa Seed ◽  
Powder Samples ◽  
Cellular Stresses ◽  
Rhizobium Leguminosarum Biovar Trifolii

Slow rehydration of bacteria from dried inoculant formulations provided higher viable counts than did rapid rehydration. Estimates were higher when clay and peat powder formulations of Rhizobium meliloti, Rhizobium leguminosarum biovar trifolii, and Pseudomonas putida, with water activities between 0.280 and 0.650, were slowly rehydrated to water activities of approximately 0.992 before continuing the dilution plating sequence. Rhizobium meliloti populations averaged 6.8 × 108 cfu/g and 1328 cfu/alfalfa seed greater when slowly rehydrated from bulk powder and preinoculated seeds, respectively. Bulk powder samples were slowly rehydrated to 0.992 water activity by the gradual addition of diluent, followed by a 10-min period for moisture equilibration. Preinoculated seed samples were placed in an environmental chamber at 24 °C with relative humidity greater than 80% for 1 h to allow moisture absorption. "Upshock," osmotic cellular stresses that occur during rehydration, was reduced when dried microbial formulations were slowly rehydrated and equilibrated before becoming fully hydrated in the dilution plating sequence. These procedures may also be applicable when estimating total viable bacterial populations from dried soil or other dry formulations. Key words: rehydration procedure, microbial rehydration, desiccation, Rhizobium, Pseudomonas.

Genetic characterization of Rhizobium sp. strain TAL1145 that nodulates tree legumes

1994 ◽  
Vol 40 (3) ◽  
pp. 208-215 ◽  
Author(s):  
M. L. C. George ◽  
J. P. W. Young ◽  
D. Borthakur
Keyword(s):  
Rhizobium Leguminosarum ◽  
Genetic Characterization ◽  
Rhizobium Meliloti ◽  
Wild Type ◽  
Tree Legumes ◽  
Wide Range ◽  
The Common ◽  
Rrna Sequences ◽  
Rhizobium Sp

Rhizobium sp. strain TALI 145 nodulates Leucaena ieucocephaia and Phaseolus vulgaris, in addition to a wide range of tropical tree legumes. Six overlapping clones that complemented nodulation defects in leucaena and bean rhizobia were isolated and a 40-kb map of the symbiosis region was constructed. The common nod and nifA genes were situated approximately 17 kb apart, with the nodlJ genes in between. These clones enabled a derivative of TAL1145 carrying a partially deleted pSym to form ineffective nodules on both leucaena and bean, and a similar derivative of Rhizobium etli TAL182 to form ineffective nodules on bean. When two representative clones, pUHR9 and pUHR114, were each transferred to wild-type rhizobial strains, they allowed ineffective nodulation by Rhizobium meliloti on both leucaena and bean and by Rhizobium leguminosarum bv. viciae on bean. Transconjugants of R. leguminosarum bv. trifolii formed effective nodules on leucaena and ineffective nodules on bean. Tn5 mutagenesis of the symbiosis region resulted in a variety of nodulation and fixation phenotypes on leucaena and bean. On the basis of 16S rRNA sequences, TAL1145 was found to be distinct from both R. tropici and NGR234, the two groups of leucaena symbionts that were previously described.Key words: Rhizobium, Leucaena leucocephala, nodulation, nitrogen fixation.

scholarly journals Genetic organization of the hydrogen uptake (hup) cluster from Rhizobium leguminosarum.

1990 ◽  
Vol 172 (3) ◽  
pp. 1647-1655 ◽  
Author(s):  
A Leyva ◽  
J M Palacios ◽  
J Murillo ◽  
T Ruiz-Argüeso
Keyword(s):  
Rhizobium Leguminosarum ◽  
Hydrogen Uptake ◽  
Genetic Organization

Phylogenetic grouping and identification of Rhizobium isolates on the basis of random amplified polymorphic DNA profiles

1993 ◽  
Vol 39 (7) ◽  
pp. 665-673 ◽  
Author(s):  
John J. Dooley ◽  
Stephen P. Harrison ◽  
Lance R. Mytton ◽  
Malcolm Dye ◽  
Ann Cresswell ◽  
...  
Keyword(s):  
Rhizobium Leguminosarum ◽  
Rhizobium Meliloti ◽  
Random Amplified Polymorphic Dna ◽  
Dna Amplification ◽  
Distinct Group ◽  
Principal Coordinate Analysis ◽  
The Other ◽  
Phylogenetic Grouping ◽  
Dna Profiles ◽  
Selection Of

Through the use of a single, random 15mer as a primer, between 1 and 12 DNA amplification products were obtained per strain from a selection of 84 Rhizobium and Bradyrhizobium isolates. A principal-coordinate analysis was used to analyse the resulting amplified DNA profiles and it was possible to assign isolates to specific groupings. Within the species Rhizobium leguminosarum, the biovar phaseoli formed a distinct group from the other biovars of the species, viciae and trifolii, which grouped together. Isolates of Rhizobium meliloti and Bradyrhizobium species formed their own clear, specific groups. Although it was possible to identify individual isolates on the basis of differences in their amplified DNA profiles, there was evidence that some amplified segments were conserved among individuals at the biovar and species levels.Key words: Rhizobium, DNA amplification, random primers.

Mutation to auxotrophy and prototrophy as related to symbiotic effectiveness in Rhizobium leguminosarum and R. trifolii

1969 ◽  
Vol 15 (6) ◽  
pp. 611-622 ◽  
Author(s):  
E. A. Schwinghamer
Keyword(s):  
Rhizobium Leguminosarum ◽  
Auxotrophic Mutant ◽  
Metabolic Inhibitors ◽  
Nutritional Requirement ◽  
Metabolic Defects ◽  
Resistant Mutants ◽  
The Relationship ◽  
Derivatives Of ◽  
Very High

Auxotrophs were isolated from four effective strains of Rhizobium leguminosarum and R. trifolii for a study of the relationship between metabolic defects and loss of ability for symbiosis. Most auxotrophs were isolated indirectly by prior isolation of mutants for resistance to metabolic inhibitors, especially D-alanine and D-histidine. The likelihood of some nutritional requirement was greatly increased among such resistant mutants, and was very high for derivatives of the R. trifolii strains. The complexity of growth factor requirement varied greatly between auxotrophs, and few had simple requirements. The most common requirement was for vitamins, notably thiamine. Partial or full restoration of effectiveness in symbiosis often accompanied reversion to prototrophy in some ineffective auxotrophs. The frequency of some degree of restoration among prototrophs varied from 0% to 100%, depending on the auxotrophic mutant involved. In one ineffective auxotroph of R. trifolii strain T1 the level of reversion (partial to complete) in vitro varied considerably and generally paralleled the degree of restoration of effectiveness. Biochemical deficiency appeared to be meaningfully related to impaired symbiosis in some auxotrophs but the relationship was probably incidental in most others. These auxotroph–prototroph studies are considered from the standpoint of relationship to several areas of research on Rhizobium.

scholarly journals Cloning, Sequencing, and Characterization of thecgmB Gene of Sinorhizobium meliloti Involved in Cyclic β-Glucan Biosynthesis

1999 ◽  
Vol 181 (15) ◽  
pp. 4576-4583 ◽  
Author(s):  
Ping Wang ◽  
Cheryl Ingram-Smith ◽  
Jill A. Hadley ◽  
Karen J. Miller
Keyword(s):  
Sinorhizobium Meliloti ◽  
Rhizobium Leguminosarum ◽  
Genomic Library ◽  
Rhizobium Meliloti ◽  
Functional Expression ◽  
Open Reading Frames ◽  
Inverse Pcr ◽  
Insertion Mutant ◽  
Overlapping Open Reading Frames ◽  
Reading Frames

ABSTRACT Periplasmic cyclic β-glucans of Rhizobium species provide important functions during plant infection and hypo-osmotic adaptation. In Sinorhizobium meliloti (also known asRhizobium meliloti), these molecules are highly modified with phosphoglycerol and succinyl substituents. We have previously identified an S. meliloti Tn5 insertion mutant, S9, which is specifically impaired in its ability to transfer phosphoglycerol substituents to the cyclic β-glucan backbone (M. W. Breedveld, J. A. Hadley, and K. J. Miller, J. Bacteriol. 177:6346–6351, 1995). In the present study, we have cloned, sequenced, and characterized this mutation at the molecular level. By using the Tn5 flanking sequences (amplified by inverse PCR) as a probe, an S. meliloti genomic library was screened, and two overlapping cosmid clones which functionally complement S9 were isolated. A 3.1-kb HindIII-EcoRI fragment found in both cosmids was shown to fully complement mutant S9. Furthermore, when a plasmid containing this 3.1-kb fragment was used to transformRhizobium leguminosarum bv. trifolii TA-1JH, a strain which normally synthesizes only neutral cyclic β-glucans, anionic glucans containing phosphoglycerol substituents were produced, consistent with the functional expression of an S. meliloti phosphoglycerol transferase gene. Sequence analysis revealed the presence of two major, overlapping open reading frames within the 3.1-kb fragment. Primer extension analysis revealed that one of these open reading frames, ORF1, was transcribed and its transcription was osmotically regulated. This novel locus of S. meliloti is designated thecgm (cyclic glucan modification) locus, and the product encoded by ORF1 is referred to as CgmB.

PCR as an ecological tool to determine the establishment and persistence of Rhizobium strains introduced into the field as seed inoculant Diane

1998 ◽  
Vol 49 (6) ◽  
pp. 923 ◽  
Author(s):  
M. Hebb ◽  
Alan E. Richardson ◽  
R. Reid ◽  
John Brockwell
Keyword(s):  
Rhizobium Leguminosarum ◽  
Field Experiments ◽  
Rhizobium Meliloti ◽  
Pcr Amplification ◽  
Field Trials ◽  
Rhizobium Strains ◽  
Inoculant Strain ◽  
Pcr Method ◽  
Polymerase Chain ◽  
Field Plots

Appraisal of the establishment and persistence of inoculant strains, and the diversity of the rhizobial populations in 2 field experiments, required the precise characterisation of isolates from individual nodules. The polymerase chain reaction (PCR) method of generating randomly amplified polymorphic DNA (RAPD) from simple bacterial cell lysates was applied to nodule isolates obtained from field plots of clover (Trifolium spp.) and medic (Medicago spp.) plants inoculated with Rhizobium leguminosarum bv. Trifolium and Rhizobium meliloti. Comparison of the PCR method with gel immune diffusion serology was applied to selected nodule isolates obtained from the clover trial. Agreement between the methods was high (97·6%). Further characterisation of nodule isolates from the 2 field trials proceeded using PCR amplification profiles only, which allowed a large number of isolates to be quickly and precisely identified. Mean recovery of inoculant strains in the first season of the clover trial was 76·5% across 10 hosts, and 45·3% in the second season sampling. Recovery of inoculant strains in the medic trial was assessed only during the second season of growth, which recorded a mean recovery of 53% across 8 hosts. In addition to providing a rapid and reliable means of identifying inoculant strains of R. leguminosarum bv. Trifolium and R. meliloti directly in association with a range of different host plants, the PCR approach also allowed inoculant strain types to be readily identified when recovered as isolates from plots in which they had not been introduced. Analysis of the non-inoculant strains by PCR also indicated that the naturalised populations of rhizobia at both sites were highly diverse.

Typing of Rhizobium by phages

1970 ◽  
Vol 16 (10) ◽  
pp. 1003-1009 ◽  
Author(s):  
Ryszard Staniewski
Keyword(s):  
Rhizobium Leguminosarum ◽  
Rhizobium Meliloti ◽  
Rhizobium Trifolii ◽  
Rhizobium Phaseoli ◽  
Group Iii ◽  
Phage Types ◽  
Group I ◽  
Rhizobium Lupini ◽  
Distinguished Group ◽  
Established Group

Two hundred and thirty strains of Rhizobium trifolii, Rhizobium leguminosarum for pea, vetch, horse bean, and Lathyrus spp., Rhizobium phaseoli and Rhizobium meliloti were subjected to phage typing. On the basis of their sensitivity to phages these strains were divided into three groups: I, II, and III.In group I, consisting of R. trifolii, R. leguminosarum for pea, vetch, and horse bean, and R. phaseoli, 18 phage types were established. Group II included some strains of R. trifolii and R. leguminosarum for pea and vetch. Among them three phage types were distinguished. Group III included R. meliloti strains and one strain of Rhizobium lupini for lupine. In that group 10 phage types were found.

scholarly journals Plasmid-Encoded Catabolic Genes in Rhizobium leguminosarum bv. trifolii: Evidence for a Plant-Inducible Rhamnose Locus Involved in Competition for Nodulation

1998 ◽  
Vol 11 (12) ◽  
pp. 1175-1185 ◽  
Author(s):  
Ivan J. Oresnik ◽  
Laurie A. Pacarynuk ◽  
Shelley A. P. O'Brien ◽  
Christopher K. Yost ◽  
Michael F. Hynes
Keyword(s):  
Rhizobium Leguminosarum ◽  
Wild Type Strain ◽  
Genomic Library ◽  
Carbon Sources ◽  
Gene Replacement ◽  
Catabolic Genes ◽  
Nodulation Competitiveness ◽  
Clover Root ◽  
Derivatives Of ◽  
Isogenic Strains

Cosmids carrying genes involved in utilization of rhamnose, sorbitol, and adonitol were isolated from a genomic library of Rhizobium leguminosarum by complementation of plasmid-cured derivatives of strain Rlt100 that were unable to grow on these carbon sources. Transposon mutagenesis was used to identify regions of each cosmid necessary for catabolism of the respective carbon source; partial DNA sequencing, as well as analysis of gene fusions created with transposon Tn5-B20, helped to determine the orientation and possible function of genes required for growth on the three substrates. Representative Tn5 insertions in the cosmids were recombined into the wild-type strain Rlt100 by gene replacement to generate isogenic strains unable to use either rhamnose, sorbitol, or adonitol. These strains were tested for their nodulation competitiveness compared with Rlt100 in co-inoculation experiments on clover plants. While sorbitol and adonitol catabolic mutants were unaltered in their competitive behavior, the nodulation competitiveness of three different rhamnose utilization mutants was significantly impaired. This result, coupled with the fact that the rhamnose catabolic genes were inducible by clover root extracts, suggests an important role for rhamnose catabolism in the early stages of the interaction of R. leguminosarum with clover plants. Hybridization studies with probes derived from the rhamnose, sorbitol, and adonitol catabolic loci demonstrated that these genes are plasmid encoded in virtually all R. leguminosarum strains, including representatives from all three biovars from a variety of different geographic locations.

An Fnr-like protein encoded in Rhizobium leguminosarum biovar viciae shows structural and functional homology to Rhizobium meliloti FixK

1990 ◽  
Vol 223 (1) ◽  
pp. 138-147 ◽  
Author(s):  
Sergio Colonna-Romano ◽  
Walter Arnold ◽  
Andreas Schlüter ◽  
Pierre Boistard ◽  
Alfred Pühler ◽  
...  
Keyword(s):  
Rhizobium Leguminosarum ◽  
Rhizobium Meliloti ◽  
Functional Homology
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