DNA Homologies between Rhizobium fredii, Rhizobia That Nodulate Galega sp., and Other Rhizobium and Bradyrhizobium Species

Wedlock, D. Neil; Jarvis, B. D. W.

doi:10.1099/00207713-36-4-550

Cited by 28 publications

(14 citation statements)

References 28 publications

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“…Thus, on the basis of its phenotypic characters, the broad-host-range strain NGR 234 was closely related to the fast-growing soybean microsymbiont R. fredii USDA 191 (cluster 3), consistent with the results obtained by others from a comparison of 16s rRNA sequences (7). The other R. fiedii strain, which originates from India, was grouped with the R. meliloti strains (cluster 5), and this is also in agreement with the published phylogenetic data for these two species (7,30,35). Strains of R. loti showed a close phenotypic relatedness to strains of R. huakuii (cluster 6, excepting strain CCBAU 2604), which also in accordance with results obtained previously by using 16s rRNA sequence comparisons (20,31).…”

Section: Discussionsupporting

confidence: 80%

Numerical Taxonomy of Rhizobium Strains from Legumes of the Temperate Zone

Novikova¹,

Павлова²,

Vorobjev³

et al. 1994

International Journal of Systematic Bacteriology

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Phenotypic properties (growth characteristics, utilization of carbon and nitrogen sources, and intrinsic antibiotic resistance) of 53 Rhizobium strains isolated from root nodules of the temperate-zone legumes Astragalus spp. (29 strains), Oxytropis campanuhta (7 strains), Hedysarum alpinum (7 strains), Ononis awensis (3 strains), Glycyrrhiza spp. (4 strains), and Coronilh varia (3 strains) were compared with those of other Rhizobium, Bradyrhizobium, and Agrobacterium strains. The final matrix, containing 83 strains and 56 nonsymbiotic features, was used for computer cluster analysis. The dendrogram showed that the new strains of temperate-zone rhizobia formed a cluster separate from both Rhizobium and Bradyrhizobium spp. Two large groups of temperate-zone rhizobia were revealed. Group 1 included rhizobial strains originating from different geographical regions with a temperate climate, while group 2 included strains from the same geographical origin, South Siberia. The 'strains of recognized Rhizobium species were clustered, in general, with each other as expected from phylogenetic relatedness.Root nodule bacteria of the genera Rhizobium and Bradyrhizobium are a common microflora of temperate soils. These bacteria may interact with the roots of leguminous plants, inducing the formation of nodules in which the fixation of atmospheric nitrogen occurs. These bacteria are commonly used in agriculture for improvement of plant growth. The specificity of the interaction between rhizobia and legumes depends on many factors coded for by the host cultivar and bacterial genomes;. The main properties of a bacterial isolate can be described by its taxonomical position in relation to other strains. There are several Rhizobium species recognized at this time (10, 1.3, 24), and knowledge of rhizobial evolution and phylogeny obtained in recent studies allows the proposal of new rhizobial taxa (3,16,25). However, the current systematic description of the genus Rhizobium does not include many of the root nodule isolates from legumes of tropical (22, 37), arctic (21), and temperate (5, 12, 17) regions.The host plant specificities and phage sensitivities of Rhizobium strains from temperate-zone legume root nodules formed on Astragalus, Hedysamm, Glycywhiza, and Ononis plants were recently described (17). It was shown that these strains constitute a cross-inoculation group related to Rhizobium loti. The aim of the present work was to determine the cultural properties of these strains and to compare these properties with those of other Rhizobium species. MATERIALS AND METHODSBacterial strains. Bacterial strains used in this work are listed in Table 1. Bacteria were maintained on yeast extractmannitol (YEM) (29) agar slants at 4°C.Growth characteristics. The time necessary for full colony development on YEM agar (estimated here as a colony diameter of 2 mm) was determined. Bacterial growth on meat-peptone agar and reactions with litmus milk were determined as described earlier (11). The ability of strains to grow in the presence of 0,1...

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Section: Discussionsupporting

confidence: 80%

Numerical Taxonomy of Rhizobium Strains from Legumes of the Temperate Zone

Novikova¹,

Павлова²,

Vorobjev³

et al. 1994

International Journal of Systematic Bacteriology

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“…More recently, the relationships between R. fredii and the recognized species of Rhizobium and Brudyrhizobium were investigated by using DNA-DNA hybridization, legume nodulation tests, and phage typing (23). The results provided evidence that the R. fredii strains form a distinct DNA homology group which can be divided into subgroups.…”

Section: Discussionmentioning

confidence: 92%

“…Based on the results of cross-inoculation, phage-typing, and DNA-DNA hybridization experiments, it was concluded that R . fredii is taxonomically distinct from other known species in the genera Rhizobium and Bradyrhizobium (23). In addition, according to DNA homology data (23) and serological relatedness data (3,12), strains USDA 194, USDA 201, and USDA 257 were distinguished from other strains of fast-growing soybean rhizobia.…”

Section: Discussionmentioning

confidence: 99%

Numerical Taxonomic Study of Fast-Growing Soybean Rhizobia and a Proposal that Rhizobium fredii Be Assigned to Sinorhizobium gen. nov.

Chen

Yan

1988

International Journal of Systematic Bacteriology

306

181

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A total of 33 strains of fast-growing soybean rhizobia isolated from soil and soybean nodules collected in China and 25 strains belonging to the genera Rhizobium, Bradyrhizobium, and Agrobacteriurn were compared by numerical taxonomic techniques, using 240 different characters, Our results indicated that all of the strains of fast-growing soybean rhizobia which we examined are closely related (guanine-plus-cytosine content, 59.9 to 63.8 mol%) and are separated from Rhizobium and Bradyrhizobium at the generic level. Based on numerical taxonomy, deoxyribonucleic acid (DNA) base ratio determinations, DNA-DNA hybridization data, serological analysis data, the composition of extracellular gum, bacteriophage typing data, and soluble protein patterns, we propose that the fast-growing soybean rhizobia represent members of a new genus rather than a species of Rhizobium (Rhizobium fredii); we propose Sinorhizobium gen. nov. as an appropriate generic name. (4). Rhizobium includes three species, Rhizobium meliloti,Rhizobium loti, and Rhizobium leguminosarum. Bradyrhizobium has only one species, Bradyrhizobium japonicum, and includes strains that are capable of nodulating lupines, soybeans, and certain other legumes (4).Recently, a new group of fast-growing soybean rhizobia was identified from soil and soybean nodules collected in the People's Republic of China by Chinese and American scientists (6, 25). The taxonomic status of these bacteria was uncertain, but they may represent a transitional group falling between the genera Rhizobium and Bradyrhizobium (4).Scholla and Elkan (13) proposed a new species name for this group, Rhizobium fredii, based mainly on deoxyribonucleic acid (DNA) hybridization comparisons of five strains of these bacteria with representatives of the genera Rhizobium and Brudyrhizobium and on a review of some of the characteristics of 11 strains of fast-growing soybean rhizobia.To extend the current information on the fast-growing soybean bacteria, we performed a numerical taxonomic study of a large number of strains. We propose that they be assembled in a new genus that includes two species. MATERIALS AND METHODSOrganisms. A total of 58 strains were used in this study (Table 1); 33 strains were fast-growing soybean rhizobia isolated from soil and soybean nodules collected in the People's Republic of China, and the other 25 strains were representatives of Rhizobium, ~r u d y r~i z o~i u m , and Agrobacterium.Features. Each of the 58 strains was characterized by determining 240 different coding features. The following features were considered: (i) utilization as sole carbon sources (0.1%) of cellobiose, D-mannose, salicin, ammonium tartrate, casein hydrolysate, fructose, sodium acetate, sorbose, riffinose, D-melezitose monohydrate, hexose 6-phos- (iv) tolerance to dyes (0.1%, wt/vol), such as sudan 1, erythrosin A, picrocarmine, safranine T, orcein, rosanilin, brilliant cresyl blue, gentian violet, bromthymol blue, bromophenol blue, methyl red, bromocresol purple, neutral red, auramine O.B.S, light gree...

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“…Features that distinguish goat's rue rhizobial strains from other bacteria within the genus Rhizobium are DNA homology (13,28), rRNA-DNA homology (8), bacteriophage typing (11,13), lipopolysaccharide and protein patterns (18), and metabolic properties (14). For example, the mean relative DNA homology between 10 strains nodulating Galega sp.…”

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confidence: 99%

Restriction fragment length polymorphism analysis of Rhizobium galegae strains

Kaijalainen

Lindström

1989

J Bacteriol

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Total DNA of various Rhizobium galegae strains representing different geographical origins, and taxonomic divergence was digested with three restriction enzymes separately, Southern blotted, and hybridized with six heterologous probes. The sequence divergences for different pairwise comparisons were calculated from proportions of conserved hybridizing fragments. The unweighted pair group method was used to group the strains. The symbiotic common nod and niJHDK probes used were highly conserved and grouped the strains according to the host plant, Galega orientalis or G. officinalis. The grouping derived from combined data of the constitutive hemA, gInA, ntrC, and recA probes was similar to that obtained in total DNA-DNA hybridization experiments. The constitutive probes grouped the strains in a different order than did the symbiotic probes, a result that may reflect interstrain transfer of symbiotic sequences in the course of evolution.Fast-growing rhizobia nodulating the legume species Galega officinalis and G. orientalis (goat's rue) have recently received attention because of the potential agronomic importance of their host plants as perennial nitrogen-fixing forage crops for temperate regions (10,12,15,27). Features that distinguish goat's rue rhizobial strains from other bacteria within the genus Rhizobium are DNA homology (13, 28), rRNA-DNA homology (8), bacteriophage typing (11, 13), lipopolysaccharide and protein patterns (18), and metabolic properties (14). For example, the mean relative DNA homology between 10 strains nodulating Galega sp. with reference DNA from strain HAMBI (The Culture Collection at the Department of Microbiology, University of Helsinki) 540, which forms effective (nitrogen-fixing) nodules on G. orientalis, was 77 ± 9%, compared with 19 ± 16% homology between HAMBI 540 and other rhizobia and bradyrhizobia (13). The Galega rhizobia are also very host specific, nodulating only their own host plants. Similarly, rhizobia from other species do not normally infect the Galega plants (13,16). The Galega rhizobia infect their host plants through the root hairs and form nodules with an apical meristem. Strains isolated from G. orientalis form effective nodules on that plant but ineffective nodules on G. officinalis and vice versa (13,17). It has recently been suggested that the Galega rhizobia form their own species, Rhizobium galegae (10).In this work, we studied the genetic relatedness between R. galegae strains representing different geographic origins and taxonomic divergence observed in earlier studies. Four strains of G. orientalis and seven strains of G. officinalis were included. Total DNA isolated from the strains was digested with restriction enzymes and hybridized separately to sequences carrying common nod genes of Rhizobium meliloti, nifHDK, hemA, and recA genes of R. meliloti, and glnA and ntrC genes of Azorhizobium caulinodans. Restriction fragment length polymorphism of fragments hybridizing with the DNAs was used to calculate the sequence divergences between the strains; on th...

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DNA Homologies between Rhizobium fredii, Rhizobia That Nodulate Galega sp., and Other Rhizobium and Bradyrhizobium Species

Cited by 28 publications

References 28 publications

Numerical Taxonomy of Rhizobium Strains from Legumes of the Temperate Zone

Numerical Taxonomy of Rhizobium Strains from Legumes of the Temperate Zone

Numerical Taxonomic Study of Fast-Growing Soybean Rhizobia and a Proposal that Rhizobium fredii Be Assigned to Sinorhizobium gen. nov.

Restriction fragment length polymorphism analysis of Rhizobium galegae strains

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