Статті в журналах: "Leguminosarum"

1

Laguerre, Gisèle, Marc Bardin, and Noëlle Amarger. "Isolation from soil of symbiotic and nonsymbiotic Rhizobium leguminosarum by DNA hybridization." Canadian Journal of Microbiology 39, no. 12 (December 1, 1993): 1142–49. http://dx.doi.org/10.1139/m93-172.

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A procedure based upon DNA hybridization was developed for the specific detection of Rhizobium leguminosarum and its different biovars among bacteria isolated from soil. DNA colony hybridization and restriction fragment length polymorphism analysis with a R. leguminosarum chromosomal probe were found to be species specific for R. leguminosarum and Rhizobium etli. By using R. leguminosarum nod gene probes, biovar specificity was obtained. Of 302 soil isolates screened for their inability to grow on Luria-Bertani agar medium, 13 strains could be assigned to the R. leguminosarum species on the basis of DNA homology to the chromosomal probe and antibiotic resistance tests. Of these strains, three and two were assigned by colony hybridization and subsequent plant host specificity tests, respectively, to R. leguminosarum biovars viciae and trifolii. The eight other R. leguminosarum soil isolates lacked symbiotic information but were able to gain nodulation capacity with the acquisition of a conjugative symbiotic plasmid. They were thus considered as nonsymbiotic R. leguminosarum.Key words: Rhizobium leguminosarum, DNA hybridization, soil, symbiotic genes.

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2

KUCEY, R. M. N. "RESPONSES OF FIELD BEAN (Phaseolus vulgaris L.) TO LEVELS OF Rhizobium leguminosarum bv. phaseoli INOCULATION IN SOILS CONTAINING EFFECTIVE R. leguminosarum bv. phaseoli POPULATIONS." Canadian Journal of Plant Science 69, no. 2 (April 1, 1989): 419–26. http://dx.doi.org/10.4141/cjps89-053.

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Greenhouse studies were conducted to determine the effect of adding Rhizobium leguminosarum bv. phaseoli inocula to field beans (Phaseolus vulgaris L.) growing in soils already containing R. leguminosarum bv. phaseoli. Indigenous R. leguminosarum bv. phaseoli populations in the 12 soils used ranged from 1.1 × 101 to 4 × 105 rhizobia g−1 of soil. Antibiotic-resistant isolates of R. leguminosarum bv. phaseoli strain 3644 were used as inocula and inoculum levels ranged from 104 to 108 bacteria per seed. N-15 isotope dilution methods with barley as a nonfixing control plant were used to determine N2 fixation levels. Bean plants grown in soils containing greater than 8 × 10 R. leguminosarum bv. phaseoli did not show positive responses to added rhizobia, except in one soil where the inoculum formed a significant proportion of nodules on inoculated plants. Plants growing in soils with less than 8 × 103R. leguminosarum bv. phaseoli did show increased levels of plant N accumulation and dry matter production in response to rhizobium addition if the level of soil mineral N was less than 25 μg N g−1 soil. Nodule occupancy by the marked R. leguminosarum bv. phaseoli isolate increased only in soils containing 8 × 103R. leguminosarum bv. phaseoli or less. The resident population of rhizobia in many of the soils was determined to be effective in N2 fixation since the proportion of N derived from N2 fixation did not increase in response to inoculation. Increasing the number of R. leguminosarum bv. phaseoli added per seed from 104 to 108 did not generally increase the effectiveness of the added inocula. Responses of beans to R. leguminosarum bv. phaseoli inoculation can only be expected in soils with low levels of resident R. leguminosarum bv. phaseoli and mineral N.Key words: Field bean, nodule occupancy, N-15 dilution, competition, N2 fixation

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3

Enibukun, Jesupemi Mercy, and Bolatito Esther Boboye. "Molecular characterization and evaluation of crude oil remediation potential of some rhizobia isolated from plant root nodules." Nova Biotechnologica et chimica 19, no. 1 (June 30, 2020): 80–88. http://dx.doi.org/10.36547/nbc.v19i1.580.

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This study aimed to determine the molecular identities and genetic relatedness of rhizobia isolated from pigeon pea and pinto beans, and assess their remediation potential in the presence of 1 %, 3 % and 5 % (w/v) crude oil in minimal medium for 7 days incubation period. Standard microbiological and molecular methods which include amplification and purification of 16S rRNA, agarose gel electrophoresis, and sequencing. Results showed molecular identities of six rhizobia from pigeon peas as Bradyrhizobium diazoefficiens USDA122, Rhizobium leguminosarum WSM2304, Bradyrhizobium japonicum N61, Rhizobium leguminosarum N741, Rhizobium leguminosarum BIHIB1217, and Bradyrhizobium japonicum E109; and three rhizobia obtained from pinto beans were Rhizobium leguminosarum N871, Bradyrhizobium diazoefficiens USDA110 and Bradyrhizobium japonicum SEMIA5079. All tested rhizobia (9) showed petroleum degradation ability, as they all grew in the 1, 3 and 5 % (w/v) crude oil minimal medium under laboratory conditions. B. diazoefficiens USDA122 showed the highest optical density (OD) value of 1.184 ± 0.05 on 7th day at 1 % (w/v) crude oil contamination, while R. leguminosarum N741 has the lowest OD value of 0.372 ± 0.02 at 5 % (w/v) crude oil on 7th day. For all the rhizobia, increase occurred throughout incubation period at 1, 3 and 5 % (w/v) except Rhizobium leguminosarum N741 and R. leguminosarum BIHIB1217. In conclusion, the association of R. leguminosarum BIHIB1217 and R. leguminosarum N871 from pigeon pea and pinto beans respectively, were found most effective in crude oil degradation and thus they are recommended as a promising association for remediation of crude oil spilled soils.

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4

Soberón-Chávez, Gloria, and Rebeca Nájera. "Isolation from soil of Rhizobium leguminosarum lacking symbiotic information." Canadian Journal of Microbiology 35, no. 4 (April 1, 1989): 464–68. http://dx.doi.org/10.1139/m89-071.

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Bacteria resembling Rhizobium leguminosarum, but lacking symbiotic information, were isolated from soil of two different geographical origins. One of these bacteria belongs to a previously described Rhizobium leguminosarum bv. phaseoli somatic serogroup, is fully complemented for nodulation and nitrogen fixation by an R. leguminosarum bv. phaseoli symbiotic plasmid, and is able to compete for bean nodulation with indigenous R. leguminosarum bv. phaseoli strains. This is the first report giving evidence for persistence in soil of Rhizobium lacking symbiotic information.Key words: Rhizobium ecology, symbiotic plasmid, nodulation, plasmid transfer.

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5

Díaz-Mireles, E., M. Wexler, G. Sawers, D. Bellini, J. D. Todd, and A. W. B. Johnston. "The Fur-like protein Mur of Rhizobium leguminosarum is a Mn2+-responsive transcriptional regulator." Microbiology 150, no. 5 (May 1, 2004): 1447–56. http://dx.doi.org/10.1099/mic.0.26961-0.

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In wild-type Rhizobium leguminosarum, the sitABCD operon specifies a Mn2+ transporter whose expression is severely reduced in cells grown in the presence of this metal. Mutations in the R. leguminosarum gene, mur (manganese uptake regulator), whose product resembles the Fur transcriptional regulator, cause high-level expression of sitABCD in the presence of Mn2+. In gel-shift mobility assays, purified R. leguminosarum Mur protein bound to at least two regions near the sitABCD promoter region, although this DNA has no conventional consensus Fur-binding sequences (fur boxes). Thus, in contrast to γ-proteobacteria, where Fur binds Fe2+, the R. leguminosarum Fur homologue, Mur, act as a Mn2-responsive transcriptional regulator.

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6

Shahzad, Farood, Muhammad Kamran Taj, Ferhat Abbas, Muhammad Shafee, Safed Ahmed Essote, Imran Taj, and Abdul Manan Achakzai. "Microbiological studies on Rhizobium leguminosarum isolated from pea (Pisum sativum L.)." Bangladesh Journal of Botany 48, no. 4 (December 31, 2019): 1223–29. http://dx.doi.org/10.3329/bjb.v48i4.49079.

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Rhizobia are the true bacteria that establish symbiotic relationship leading to the development of new root nodules. This study has been designed to evaluate the microbiological aspects of Rhizobium leguminosarum in target area. A total of 1000 (200 from each site) roots were collected from five different agriculture fields (Quetta, Pishin, Killa Abdulla, Kuchlak and Hanna Urak) and screened through different standard microbiological procedures. Results revealed that 665/1000 (66.5%) roots samples were positive for Rhizobium leguminosarum. The highest percentage was from Pishin 180/200 (18%) and Killa Abdullah 160/200 (16%). A remarkable growth of Rhizobium leguminosarum was noted at 28 to 30°C whereas, less growth was recorded at 24, 34 and 42°C. Similarly, Rhizobium leguminosarum showed growth at pH 5 to 10, but superlative pH values for the growth of Rhizobium leguminosarum were from 6 to 8 pH. The PCR reconfirmed 1300 bp band of 16S rRNA gene of Rhizobium leguminosarum. The organism was further applied as biofertilizer and showed promising results in subjected plants. Medicinal plants application showed that Rhizobium leguminosarum was sensitive to different plants. However, the effects of insecticides showed that Cypermethrin exhibited least zone of inhibition 10 and 11 mm, while Chlorpyrifos showed least zone of inhibition 14 and 17 mm by using disc and well method with (1: 16) dilution. These findings ensure the devastation of microbiota in rhizosphere with rational use of these pesticides that may result in adverse effects over crop productions in the region.

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7

Vershinina, Z. R., Lavina, and O. V. Chubukova. "Exopolysaccharides of Rhizobium leguminosarum — an overview." Biomics 12, no. 1 (2020): 27–49. http://dx.doi.org/10.31301/2221-6197.bmcs.2020-3.

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8

Furtak, Karolina, Karolina Gawryjołek, Anna Gałązka, and Jarosław Grządziel. "The Response of Red Clover (Trifolium pratense L.) to Separate and Mixed Inoculations with Rhizobium leguminosarum and Azospirillum brasilense in Presence of Polycyclic Aromatic Hydrocarbons." International Journal of Environmental Research and Public Health 17, no. 16 (August 9, 2020): 5751. http://dx.doi.org/10.3390/ijerph17165751.

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This study aimed to evaluate the impact of co-inoculation Rhizobium sp. and Azospirillum sp. on plant (Trifolium pratense L.) growth in the presence of polycyclic aromatic hydrocarbon (PAH) contamination (anthracene, phenanthrene, and pyrene). Eight strains from the genus Rhizobium leguminosarum bv. trifolii were selected for biotest analysis. Two methods of inoculation were used in the chamber experiment: (1) R. leguminosarum alone and (2) a combined inoculant (R. leguminosarum and Azospirillum brasilense). For comparison, non-contaminated controls were also used. The results demonstrated that co-inoculation of plants with Rhizobium and Azospirillum resulted in more root and shoot biomass than in plants inoculated with R. leguminosarum alone. The results indicated that application of a co-inoculation of bacteria from Rhizobium and Azospirillum species had a positive effect on clover nodulation and growth under the condition of PAH contamination.

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9

He, Ya Hui, Gao Bao Huang, and Li Zhuo Guo. "The Use of ¹⁵N to Measure N2-Fixing Effectiveness of Rhizobium leguminosarum Strains." Advanced Materials Research 287-290 (July 2011): 2023–27. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2023.

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Biomass, N derived from BNF, total N and Ndfa % of different part tissues of pea plants inoculated with various Rhizobium. leguminosarum strains were determined. Particularly identified were whole plant biomass correlated with N derived from BNF. The significant direct correlations between biomass and N derived from BNF indicated that N-fixation efficiency of strains are important factors influencing biomass accumulation of plants, but not the sole factors determine the promoted capacity of strain on plant biomass production. Different strains show various performances on accumulation of biomass in different parts of plant tissue, R. leguminosarum SY12 performed best on promotion of kernel production. In order to obtain aimed strain with particular property such as promotion of kernel production, the15N tracing technique can be used in R. Leguminosarum strains screening of R. Leguminosarum, but the analysis both separate part and whole plant tissue are necessary.

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10

Brozek, Kathryn A., Julie L. Kadrmas, and Christian R. H. Raetz. "Lipopolysaccharide Biosynthesis inRhizobium leguminosarum." Journal of Biological Chemistry 271, no. 50 (December 13, 1996): 32112–18. http://dx.doi.org/10.1074/jbc.271.50.32112.

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11

Walker, Simon A., and J. Allan Downie. "Entry of Rhizobium leguminosarum bv. viciae into Root Hairs Requires Minimal Nod Factor Specificity, but Subsequent Infection Thread Growth Requires nodO or nodE." Molecular Plant-Microbe Interactions® 13, no. 7 (July 2000): 754–62. http://dx.doi.org/10.1094/mpmi.2000.13.7.754.

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Using various mutant strains of Rhizobium leguminosarum bv. viciae, we have investigated the role of nodO in stimulating infection thread development in vetch and pea. Analysis of R. leguminosarum bv. viciae nodE and nodO mutants revealed no significant difference from the wild-type infection phenotype. Conversely, an R. leguminosarum bv. viciae nodE nodO double mutant was severely impaired in its ability to form normal infection threads. This strain displayed a number of novel infection-related events, including intracellular accumulations of bacteria at the base of root hairs, distended and enlarged infection threads, and reversed threads growing up root hairs. Since normal infection was seen in a nodE mutant, nodO must suppress these abnormal infection phenomena. A deletion mutant, retaining only the nodD and nodABCIJ genes, also formed intracellular accumulations at the base of root hairs. Addition of R. leguminosarum bv. viciae nodO could alleviate this phenotype and restore some infection thread formation, although these threads appeared to be abnormal. Exogenous application of R. leguminosarum bv. viciae Nod factors could not alleviate the aberrant infection phenotype. Our results show that the most basic Nod factor structure can allow bacterial entry into the root hair, and that nodO can promote subsequent infection thread development.

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12

Hood, Graham, Ramakrishnan Karunakaran, J. Allan Downie, and Philip Poole. "MgtE From Rhizobium leguminosarum Is a Mg2+ Channel Essential for Growth at Low pH and N2 Fixation on Specific Plants." Molecular Plant-Microbe Interactions® 28, no. 12 (December 2015): 1281–87. http://dx.doi.org/10.1094/mpmi-07-15-0166-r.

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MgtE is predicted to be a Rhizobium leguminosarum channel and is essential for growth when both Mg2+ is limiting and the pH is low. N2 was only fixed at 8% of the rate of wild type when the crop legume Pisum sativum was inoculated with an mgtE mutant of R. leguminosarum and, although bacteroids were present, they were few in number and not fully developed. R. leguminosarum MgtE was also essential for N2 fixation on the native legume Vicia hirsuta but not when in symbiosis with Vicia faba. The importance of MgtE and the relevance of the contrasting phenotypes is discussed.

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13

Wexler, M., J. D. Todd, O. Kolade, D. Bellini, A. M. Hemmings, G. Sawers, and A. W. B. Johnston. "Fur is not the global regulator of iron uptake genes in Rhizobium leguminosarum." Microbiology 149, no. 5 (May 1, 2003): 1357–65. http://dx.doi.org/10.1099/mic.0.26130-0.

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Rhizobium leguminosarum fur mutants were unaffected in Fe-dependent regulation of several operons that specify different Fe uptake systems, yet cloned R. leguminosarum fur partially corrected an Escherichia coli fur mutant and R. leguminosarum Fur protein bound to canonical fur boxes. The lack of a phenotype in fur mutants is not due to functional redundancy with Irr, another member of the Fur superfamily found in the rhizobia, since irr fur double mutants are also unaffected in Fe-responsive regulation of several operons involved in Fe uptake. Neither Irr nor Fur is needed for symbiotic N2 fixation on peas. As in Bradyrhizobium japonicum, irr mutants accumulated protoporphyrin IX. R. leguminosarum irr is not regulated by Fur and its Irr protein lacks the motif needed for haem-dependent post-translational modification that occurs in B. japonicum Irr. The similarities and differences in the Fur superfamily in the rhizobia and other Gram-negative bacteria are discussed.

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14

RENNIE, R. J., and G. A. KEMP. "TEMPERATURE-SENSITIVE NODULATION AND N2 FIXATION OF Rhizobium leguminosarum BIOVAR Phaseoli STRAINS." Canadian Journal of Soil Science 66, no. 2 (May 1, 1986): 217–24. http://dx.doi.org/10.4141/cjss86-024.

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Two strains of Rhizobium leguminosarum biovar phaseoli, both previously Nod+Fix+ and efficient in N2 fixation, now have altered symbiotic properties presumably through spontaneous mutation. Rhizobium leguminosarum biovar phaseoli strain RCR 3605 was Nod−Fix− in a cool growth temperature regime (14–23 °C) and Nod+Fix− in a warm regime (17–23 °C) on seven of nine bean cultivars studied. Rhizobium leguminosarum biovar phaseoli strain CIAT 57 was Nod+Fix− in both temperature regimes. CIAT 57 and RCR 3605 are synonyms for strains derived from the same parent strain but housed in different culture collections. The nodulation deficiency in CIAT 57 is presumably genetically predetermined in the bacterium rather than in the plant because no Nod+Fix+ phenotype was identified on nine bean cultivars tested. A control R. leguminosarum biovar phaseoli strain, RCR 3644, was efficient on all cultivars. In the warm temperature regime, the Nod+Fix− phenotype was observed with strain RCR 3605 only on some cultivars, suggesting that the host plant genome played a role in this ineffective symbiosis. It is likely that deleterious genetic mutations during prolonged storage may be altering the N2-fixing ability of these rhizobial strains and that commercial inoculants must be continually monitored for symbiotic performance of strains with a variety of host plant cultivars. Key words: Field bean, Rhizobium leguminosarum biovar phaseoli, N2 fixation

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15

Rivers, Damien M. R., Derek D. Kim, and Ivan J. Oresnik. "Inability to Catabolize Rhamnose by Sinorhizobium meliloti Rm1021 Affects Competition for Nodule Occupancy." Microorganisms 10, no. 4 (March 29, 2022): 732. http://dx.doi.org/10.3390/microorganisms10040732.

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Rhizobium leguminosarum strains unable to grow on rhamnose as a sole carbon source are less competitive for nodule occupancy. To determine if the ability to use rhamnose as a sole carbon source affects competition for nodule occupancy in Sinorhizobium meliloti, Tn5 mutants unable to use rhamnose as a sole carbon source were isolated. S. meliloti mutations affecting rhamnose utilization were found in two operons syntenous to those of R. leguminosarum. Although the S. meliloti Tn5 mutants were complemented using an R. leguminosarum cosmid that contains the entire wild-type rhamnose catabolic locus, complementation did not occur if the cosmids carried Tn5 insertions within the locus. Through a series of heterologous complementation experiments, enzyme assays, gene fusion, and transport experiments, we show that the S. meliloti regulator, RhaR, is dominant to its R. leguminosarum counterpart. In addition, the data support the hypothesis that the R. leguminosarum kinase is capable of directly phosphorylating rhamnose and rhamnulose, whereas the S. meliloti kinase does not possess rhamnose kinase activity. In nodule competition assays, S. meliloti mutants incapable of rhamnose transport were shown to be less competitive than the wild-type and had a decreased ability to bind plant roots in the presence of rhamnose. The data suggests that rhamnose catabolism is a general determinant in competition for nodule occupancy that spans across rhizobial species.

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16

Janczarek, Monika, and Anna Skorupska. "The Rhizobium leguminosarum bv. trifolii RosR: Transcriptional Regulator Involved in Exopolysaccharide Production." Molecular Plant-Microbe Interactions® 20, no. 7 (July 2007): 867–81. http://dx.doi.org/10.1094/mpmi-20-7-0867.

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The acidic exopolysaccharide is required for the establishment of symbiosis between the nitrogen-fixing bacterium Rhizobium leguminosarum bv. trifolii and clover. Here, we describe RosR protein from R. leguminosarum bv. trifolii 24.2, a homolog of transcriptional regulators belonging to the family of Ros/MucR proteins. R. leguminosarum bv. trifolii RosR possesses a characteristic Cys2His2 type zincfinger motif in its C-terminal domain. Recombinant (His)6RosR binds to an RosR-box sequence located upstream of rosR. Deletion analysis of the rosR upstream region resulted in identification of two -35 to -10 promoter sequences, two conserved inverted palindromic pentamers that resemble the cAMP-CRP binding site of Escherichia coli, inverted repeats identified as a RosR binding site, and other regulatory sequence motifs. When assayed in E. coli, a transcriptional fusion of the cAMP-CRP binding site containing the rosR upstream region and lacZ gene was moderately responsive to glucose. The sensitivity of the rosR promoter to glucose was not observed in E. coli ΔcyaA. A rosR frame-shift mutant of R. leguminosarum bv. trifolii formed dry, wrinkled colonies and induced nodules on clover, but did not fix nitrogen. In the rosR mutant, transcription of pssA-lacZ fusion was decreased, indicating positive regulation of the pssA gene by RosR. Multiple copies of rosR in R. leguminosarum bv. trifolii 24.2 increased exopolysaccharide production.

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17

Kucey, R. M. N., and M. F. Hynes. "Populations of Rhizobium leguminosarum biovars phaseoli and viceae in fields after bean or pea in rotation with nonlegumes." Canadian Journal of Microbiology 35, no. 6 (June 1, 1989): 661–67. http://dx.doi.org/10.1139/m89-107.

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Populations of Rhizobium leguminosarum bv. phaesoli and bv. viceae in southern Alberta soils were measured over a period of 4 years using a most probable number method. Five fields cropped to bean (Phaseolus vulgaris L.), five fields cropped to pea (Pisum sativum L.), and two fields cropped to wheat were used as test sites. Legume crops had received appropriate legume inoculants. Fields were sampled in the fall of the crop year and in the spring of the following 3 years during which fields were cropped to nonlegumes or left fallow. Numbers of R. leguminosarum bv. phaseoli were 100 to 1000 times higher in fields that had been planted to bean than in fields that had been planted to pea or wheat. Fields that had been planted to pea maintained populations of R. leguminosarum bv. viceae 10 to 100 times higher than fields that had been planted to bean or wheat. Wheat fields, which had never had legumes grown in them, contained between 1 and 100 rhizobia per gram of soil of both biovars of R. leguminosarum, indicating that both biovars are native to southern Alberta soils. The numbers of rhizobia did not decrease in proportion to the population of other bacteria in the soil over the duration of the experiment. Plasmid profiles of soil Rhizobium isolates obtained in the last year of the experiment showed that none of the isolates had plasmid profiles similar to those of strains added as inoculants in the 1st year of the experiment. These results show that fields cropped to legumes and receiving rhizobial inoculants in this study maintained high populations of rhizobia for several years after harvest of the legume crop.Key words: Rhizobium leguminosarum bv. phaseoli, Rhizobium leguminosarum bv. viceae, nodule, plasmid profiles, inoculum potential, rhizobium competition.

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18

Mazurier, Sylvie-Isabelle, and Gisele Laguerre. "Unusual localization of nod and nif genes in Rhizobium leguminosarum bv. viciae." Canadian Journal of Microbiology 43, no. 4 (April 1, 1997): 399–402. http://dx.doi.org/10.1139/m97-056.

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Genomic DNA from seven strains of Rhizobium leguminosarum bv. viciae isolated from nodules of field-grown lentils showed homology to nod and nif gene probes, whereas plasmid DNA did not hybridize with these probes. The results suggest that symbiotic genes could be located on the chromosome or perhaps on a very large plasmid that could not be resolved in Eckhardt gels. Each strain contained one plasmid that hybridized with a pSym isolated from a R. leguminosarum strain of the same field population. This finding led us to hypothesize that the nod and nif genes of the seven strains might have originated from a Sym plasmid and have been integrated into another replicon. The ability to nodulate vetch was confirmed for all of the seven strains. Thus, wild strains of R. leguminosarum bv. viciae that nodulate vetch carry nod and nif genes either on the chromosome or on an extrachromosomal replicon of size much larger than the pSyms hitherto described.Key words: Rhizobium leguminosarum, nod genes, nif genes, chromosome, symbiotic plasmid, megaplasmid.

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19

Stambulska, U. Ya, and V. I. Lushchak. "EFFECT OF LOCAL STRAINS OF RHIZOBIUM LEGUMINOSARUM BV. VICIAE ON PEA PLANTS." Agriciltural microbiology 7 (October 23, 2008): 131–37. http://dx.doi.org/10.35868/1997-3004.7.131-137.

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Influence of inoculation with nodule bacteria Rhizobium leguminosarum bv. viciae on the efficiency of legume-rhizobium symbiosis formation as well as chlorophyll content in pea plants was studied. Seed inoculation with bacteria Rhizobium leguminosarum, strains RRL9 and RRL11 resulted in increase of aboveground plant mass and mass of nodules in the comparison with effects of inoculation with other local strains and collection Rhizobium leguminosarum 245a strain. At the initial stages of the pea ontogenesis the concentrations of chlorophyll a in all inoculated plants was more than in control. The local wild strains of pea nodule bacteria were effective in legumerhizobium symbiosis formation under specific climate conditions, which are a natural ecological niche for those bacterial strains.

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20

Yates, R. J., J. G. Howieson, D. Real, W. G. Reeve, A. Vivas-Marfisi, and G. W. O'Hara. "Evidence of selection for effective nodulation in the Trifolium spp. symbiosis with Rhizobium leguminosarum biovar trifolii." Australian Journal of Experimental Agriculture 45, no. 3 (2005): 189. http://dx.doi.org/10.1071/ea03168.

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The pasture-breeding program to improve production in the natural grasslands in Uruguay has acknowledged that indigenous Rhizobium strains are incompatible with introduced Mediterranean clovers. In an attempt to understand and overcome this problem, a cross-row experiment was set up in 1999 in a basaltic, acid soil in Glencoe, Uruguay, to follow the survival and performance of 9 exotic strains of Rhizobium leguminosarum bv. trifolii. This paper reports on the ability of the introduced strains to compete for nodule occupancy of Mediterranean clover hosts and impacts of the introduced strains on the productivity of the indigenous Uruguayan clover Trifolium polymorphum. Strain WSM1325 was a superior inoculant and remained highly persistent and competitive for the effective symbiosis with the Mediterranean hosts, T. purpureum and T. repens, in the Uruguayan environment in the third year of the experiment. The Mediterranean hosts (T. purpureum and T. repens) nodulated with the introduced strains but did not nodulate with any indigenous R. leguminosarum bv. trifolii typed from nodules of T. polymorphum. Conversely, there were no nodules on the Uruguayan host T. polymorphum that contained introduced R. leguminosarum bv. trifolii. These results reveal the establishment of effective symbioses between strains of R. leguminosarum bv. trifolii and clover even though the soil contained ineffective R. leguminosarum bv. trifolii for all hosts. We believe our results are the first reported example of ‘selective’ nodulation for an effective symbiosis in situ with annual and perennial clovers in acid soils.

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21

Sprout, Sharon L., Louise M. Nelson, and James J. Germida. "Influence of metribuzin on the Rhizobium leguminosarum–lentil (Lens culinaris) symbiosis." Canadian Journal of Microbiology 38, no. 4 (April 1, 1992): 343–49. http://dx.doi.org/10.1139/m92-058.

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The effects of the triazine herbicide metribuzin (Sencor) on the lentil (Lens culinaris Medic.) - Rhizobium leguminosarum biovar viciae symbiosis were studied in Leonard jars and growth pouches. Lentils inoculated with Rhizobium leguminosarum strain 128C54 or 128C84, and noninoculated lentils grown in plant nutrient solution supplemented with 5 mM KNO3, had metribuzin applied to the plants at either 8 or 13 days after planting. When sprayed at 8 days, metribuzin had a significant (p ≤ 0.05) negative effect on plant weight, number of nodules, taproot growth, and acetylene reduction activity. Five to 10 days after spraying, the plants began to recover from the inhibitory effects. When spraying was delayed to 13 days after planting, metribuzin had little effect on plant growth. The R. leguminosarum strain used as inoculant affected the degree of inhibition of lentil growth and the rate of plant recovery. Less than 0.2% of foliarly applied metribuzin was translocated to the root. Thus the detrimental effects of metribuzin application to lentils were mainly due to direct effects on the plant, which resulted in indirect effects on nodulation and nitrogen fixation. Key words: Rhizobium leguminosarum, lentil, metribuzin.

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Lodwig, E. M., M. Leonard, S. Marroqui, T. R. Wheeler, K. Findlay, J. A. Downie, and P. S. Poole. "Role of Polyhydroxybutyrate and Glycogen as Carbon Storage Compounds in Pea and Bean Bacteroids." Molecular Plant-Microbe Interactions® 18, no. 1 (January 2005): 67–74. http://dx.doi.org/10.1094/mpmi-18-0067.

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Rhizobium leguminosarum synthesizes polyhydroxybutyrate and glycogen as its main carbon storage compounds. To examine the role of these compounds in bacteroid development and in symbiotic efficiency, single and double mutants of R. leguminosarum bv. viciae were made which lack poly-hydroxybutyrate synthase (phaC), glycogen synthase (glgA), or both. For comparison, a single phaC mutant also was isolated in a bean-nodulating strain of R. leguminosarum bv. phaseoli. In one large glasshouse trial, the growth of pea plants inoculated with the R. leguminosarum bv. viciae phaC mutant were significantly reduced compared with wild-type-inoculated plants. However, in subsequent glasshouse and growth-room studies, the growth of pea plants inoculated with the mutant were similar to wild-type-inoculated plants. Bean plants were unaffected by the loss of polyhydroxybutyrate biosynthesis in bacteroids. Pea plants nodulated by a glycogen synthase mutant, or the glgA/phaC double mutant, grew as well as the wild type in growth-room experiments. Light and electron micrographs revealed that pea nodules infected with the glgA mutant accumulated large amounts of starch in the II/III interzone. This suggests that glycogen may be the dominant carbon storage compound in pea bacteroids. Polyhydroxybutyrate was present in bacteria in the infection thread of pea plants but was broken down during bacteroid formation. In nodules infected with a phaC mutant of R. leguminosarum bv. viciae, there was a drop in the amount of starch in the II/III interzone, where bacteroids form. Therefore, we propose a carbon burst hypothesis for bacteroid formation, where polyhydroxybutyrate accumulated by bacteria is degraded to fuel bacteroid differentiation.

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Brito, Belén, Rosa-Isabel Prieto, Ezequiel Cabrera, Marie-Andrée Mandrand-Berthelot, Juan Imperial, Tomás Ruiz-Argüeso, and José-Manuel Palacios. "Rhizobium leguminosarum hupE Encodes a Nickel Transporter Required for Hydrogenase Activity." Journal of Bacteriology 192, no. 4 (December 18, 2009): 925–35. http://dx.doi.org/10.1128/jb.01045-09.

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ABSTRACT Synthesis of the hydrogen uptake (Hup) system in Rhizobium leguminosarum bv. viciae requires the function of an 18-gene cluster (hupSLCDEFGHIJK-hypABFCDEX). Among them, the hupE gene encodes a protein showing six transmembrane domains for which a potential role as a nickel permease has been proposed. In this paper, we further characterize the nickel transport capacity of HupE and that of the translated product of hupE2, a hydrogenase-unlinked gene identified in the R. leguminosarum genome. HupE2 is a potential membrane protein that shows 48% amino acid sequence identity with HupE. Expression of both genes in the Escherichia coli nikABCDE mutant strain HYD723 restored hydrogenase activity and nickel transport. However, nickel transport assays revealed that HupE and HupE2 displayed different levels of nickel uptake. Site-directed mutagenesis of histidine residues in HupE revealed two motifs (HX5DH and FHGX[AV]HGXE) that are required for HupE functionality. An R. leguminosarum double mutant, SPF22A (hupE hupE2), exhibited reduced levels of hydrogenase activity in free-living cells, and this phenotype was complemented by nickel supplementation. Low levels of symbiotic hydrogenase activity were also observed in SPF22A bacteroid cells from lentil (Lens culinaris L.) root nodules but not in pea (Pisum sativum L.) bacteroids. Moreover, heterologous expression of the R. leguminosarum hup system in bacteroid cells of Rhizobium tropici and Mesorhizobium loti displayed reduced levels of hydrogen uptake in the absence of hupE. These data support the role of R. leguminosarum HupE as a nickel permease required for hydrogen uptake under both free-living and symbiotic conditions.

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McKAY, I. A., A. R. GLENN, and M. J. DILWORTH. "Gluconeogenesis in Rhizobium leguminosarum MNF3841." Microbiology 131, no. 8 (August 1, 1985): 2067–73. http://dx.doi.org/10.1099/00221287-131-8-2067.

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Kadrmas, Julie L., Kathryn A. Brozek, and Christian R. H. Raetz. "Lipopolysaccharide Core Glycosylation inRhizobium leguminosarum." Journal of Biological Chemistry 271, no. 50 (December 13, 1996): 32119–25. http://dx.doi.org/10.1074/jbc.271.50.32119.

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Lugtenberg, B. J. J. "Regulation of nodulation inRhizobium leguminosarum." World Journal of Microbiology & Biotechnology 8, S1 (December 1992): 120–23. http://dx.doi.org/10.1007/bf02421513.

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27

Khakimova, L. R., L. R. Karimova, and Z. R. Vershinina. "Recombinant Rhizobium leguminosarum, resistance to heavy metals." Biomics 12, no. 1 (2020): 50–56. http://dx.doi.org/10.31301/2221-6197.bmcs.2020-4.

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Bardin, Sylvie D., Hung-Chang Huang, Joanna Pinto, Eric J. Amundsen, and R. Scott Erickson. "Biological control of Pythium damping-off of pea and sugar beet by Rhizobium leguminosarum bv. viceae." Canadian Journal of Botany 82, no. 3 (March 1, 2004): 291–96. http://dx.doi.org/10.1139/b04-003.

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Rhizobium leguminosarum Jordan bv. viceae strains from pea and lentil root nodules were tested for control of damping-off of pea (Pisum sativum L., host) and sugar beet (Beta vulgaris L., nonhost) crops caused by Pythium sp. "group G". Of the 18 Rhizobium isolates tested, only strain R5 inhibited mycelial growth of Pythium sp. "group G". None of the strains showed any protease activity. Results of indoor experiments in soil artificially infested with Pythium sp. "group G" showed that 10 strains of R. leguminosarum bv. viceae were effective in increasing sugar beet emergence compared with the untreated control, when bacteria were coated onto seeds. Three of the most promising strains, R12, R20, and R21, were further tested for control of damping-off of field pea and sugar beet in a field naturally infested with Pythium spp. R12 and R20 significantly increased seedling emergence of field pea in the two field tests, compared with the untreated control. The efficacy of strains R12 and R20 was similar to that of Pseudomonas fluorescens Migula 708, a biological control agent of Pythium sp. "group G". Rhizobium leguminosarum bv. viceae strains R12 and R21 were the most effective biological control agents for control of sugar beet damping-off in the field experiments. They were as effective as seed treatment with the fungicide ThiramTM in one field experiment. The present study reveals that some R. leguminosarum bv. viceae strains, in addition to their use as biofertilizer, also have the potential to be used for biological control of Pythium damping-off of field pea and sugar beet.Key words: Rhizobium leguminosarum bv. viceae, Pythium sp. "group G", damping-off, biological control, sugar beet, pea.

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Russo, Daniela M., Alan Williams, Anne Edwards, Diana M. Posadas, Christine Finnie, Marcelo Dankert, J. Allan Downie, and Angeles Zorreguieta. "Proteins Exported via the PrsD-PrsE Type I Secretion System and the Acidic Exopolysaccharide Are Involved in Biofilm Formation by Rhizobium leguminosarum." Journal of Bacteriology 188, no. 12 (June 15, 2006): 4474–86. http://dx.doi.org/10.1128/jb.00246-06.

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ABSTRACT The type I protein secretion system of Rhizobium leguminosarum bv. viciae encoded by the prsD and prsE genes is responsible for secretion of the exopolysaccharide (EPS)-glycanases PlyA and PlyB. The formation of a ring of biofilm on the surface of the glass in shaken cultures by both the prsD and prsE secretion mutants was greatly affected. Confocal laser scanning microscopy analysis of green-fluorescent-protein-labeled bacteria showed that during growth in minimal medium, R. leguminosarum wild type developed microcolonies, which progress to a characteristic three-dimensional biofilm structure. However, the prsD and prsE secretion mutants were able to form only an immature biofilm structure. A mutant disrupted in the EPS-glycanase plyB gene showed altered timing of biofilm formation, and its structure was atypical. A mutation in an essential gene for EPS synthesis (pssA) or deletion of several other pss genes involved in EPS synthesis completely abolished the ability of R. leguminosarum to develop a biofilm. Extracellular complementation studies of mixed bacterial cultures confirmed the role of the EPS and the modulation of the biofilm structure by the PrsD-PrsE secreted proteins. Protein analysis identified several additional proteins secreted by the PrsD-PrsE secretion system, and N-terminal sequencing revealed peptides homologous to the N termini of proteins from the Rap family (Rhizobium adhering proteins), which could have roles in cellular adhesion in R. leguminosarum. We propose a model for R. leguminosarum in which synthesis of the EPS leads the formation of a biofilm and several PrsD-PrsE secreted proteins are involved in different aspects of biofilm maturation, such as modulation of the EPS length or mediating attachment between bacteria.

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Rajasekar, Kuppuraj, Thilagavathy Daniel, and Natchimuthu Karmegam. "Microbial Enrichment of Vermicompost." ISRN Soil Science 2012 (March 8, 2012): 1–13. http://dx.doi.org/10.5402/2012/946079.

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The present study has been conducted to explore the possibility of enrichment of vermicompost with microbial inoculants (i.e., biofertilizer organisms), Azospirillum brasilense and Rhizobium leguminosarum, optimization of inoculum level, and time of inoculation during vermicomposting. The survival rate of each microbial inoculant, total microbial population in vermicompost, and their correlation with the microbial inoculants during the storage period (180 days) were assessed. The change in population of A. brasilense and R. leguminosarum in vermicompost (at 30, 35, and 40 mL/175 g substrates) with reference to storage period showed highly significant negative correlation (). The total microbial population in A. brasilense and R. leguminosarum inoculated vermicompost was high during initial phases of storage and then total microbial population declined towards the end. The inoculum level of A. brasilense and R. leguminosarum at 35 mL per 175 g vermibed substrate is sufficient to maintain viable cells up to 160 days after ther harvesting of vermicompost. The inoculum of these two biofertilizer organisms into vermibed on the 30th day showed increased survival rate and, hence, the optimized inoculation of 35 mL of inoculum per 175 g substrate on the 30th day of vermicomposting is helpful for the maintenance of sufficient viable population for more than five months in the enriched vermicompost.

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Olsthoorn, Maurien M. A., Ellen Stokvis, Johan Haverkamp, Herman P. Spaink, and Jane E. Thomas-Oates. "Growth Temperature Regulation of Host-Specific Modifications of Rhizobial Lipo-Chitin Oligosaccharides: The Function of nodX Is Temperature Regulated." Molecular Plant-Microbe Interactions® 13, no. 8 (August 2000): 808–20. http://dx.doi.org/10.1094/mpmi.2000.13.8.808.

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Lipo-chitin oligosaccharides (LCOs) are usually produced and isolated for structural analysis from bacteria cultured under laboratory rather than field conditions. We have studied the influence of bacterial growth temperature on the LCO structures produced by different Rhizobium leguminosarum strains, using thin-layer chromatographic, high-performance liquid chromatographic, and mass spectrometric analyses. Wild-type R. leguminosarum bv. viciae A1 was shown to produce larger relative amounts of nodX-mediated, acetylated LCOs at 12°C than at 28°C, indicating that the activity of nodX (a gene encoding an LCO O-acetyl transferase) is temperature dependent. Interestingly, symbiotic resistance genes sym1 and sym2 found in primitive pea cultivars are also temperature sensitive, only being active at low temperatures, at which they block nodulation by R. leguminosarum bv. viciae strains lacking nodX. We therefore propose that the gene-for-gene relationship between plant and bacterium has a temperature-sensitive mechanism as an adaptation to environmental conditions. An R. leguminosarum bv. trifolii strain was also shown to produce larger relative amounts of nodX-mediated, acetylated LCOs at 12°C than at 28°C. The major components synthesized by the two strains are produced at both temperatures but in different relative amounts, while some minor components are only produced at one of the two temperatures.

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López-Lara, Isabel M., and Otto Geiger. "The Nodulation Protein NodG Shows the Enzymatic Activity of an 3-Oxoacyl-Acyl Carrier Protein Reductase." Molecular Plant-Microbe Interactions® 14, no. 3 (March 2001): 349–57. http://dx.doi.org/10.1094/mpmi.2001.14.3.349.

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The acyl carrier protein NodF is required for the synthesis of unusual polyunsaturated fatty acids that confer specificity to lipochitin oligosaccharide nodulation (Nod) factors of Rhizobium leguminosarum. In this study, homogeneous NodF protein was used as a ligand to identify proteins of R. leguminosarum that specifically interact with NodF and presumably are involved in the biosynthesis or transfer of the unusual fatty acids. The N-terminal amino acid sequence of a 29-kDa protein that interacts strongly with NodF revealed high similarity to NodG of Rhizobium sp. N33 and to NodG of Sinorhizobium meliloti. We cloned and sequenced the gene coding for the NodG-like protein of R. leguminosarum and found it to be the product of the constitutively expressed gene fabG. FabG is the 3-oxoacyl-acyl carrier protein reductase that catalyzes the first reduction step in each cycle of fatty acid elongation. FabG of R. leguminosarum and NodG of Rhizobium sp. N33 were expressed in Escherichia coli. In both cases, the purified protein showed 3-oxoacyl-acyl carrier protein reductase activity in vitro. Therefore, NodG has the same biochemical function as FabG, and the high degree of similarity at the protein and DNA level suggest that nodG is a duplication of the housekeeping gene fabG.

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Rubio-Sanz, L., R. I. Prieto, J. Imperial, J. M. Palacios, and B. Brito. "Functional and Expression Analysis of the Metal-InducibledmeRFSystem from Rhizobium leguminosarum bv. viciae." Applied and Environmental Microbiology 79, no. 20 (August 9, 2013): 6414–22. http://dx.doi.org/10.1128/aem.01954-13.

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ABSTRACTA gene encoding a homolog to the cation diffusion facilitator protein DmeF fromCupriavidus metalliduranshas been identified in the genome ofRhizobium leguminosarumUPM791. TheR. leguminosarum dmeFgene is located downstream of an open reading frame (designateddmeR) encoding a protein homologous to the nickel- and cobalt-responsive transcriptional regulator RcnR fromEscherichia coli. Analysis of gene expression showed that theR. leguminosarum dmeRFgenes are organized as a transcriptional unit whose expression is strongly induced by nickel and cobalt ions, likely by alleviating the repressor activity of DmeR ondmeRFtranscription. AnR. leguminosarum dmeRFmutant strain displayed increased sensitivity to Co(II) and Ni(II), whereas no alterations of its resistance to Cd(II), Cu(II), or Zn(II) were observed. A decrease of symbiotic performance was observed when pea plants inoculated with anR. leguminosarum dmeRFdeletion mutant strain were grown in the presence of high concentrations of nickel and cobalt. The same mutant induced significantly lower activity levels of NiFe hydrogenase in microaerobic cultures. These results indicate that theR. leguminosarumDmeRF system is a metal-responsive efflux mechanism acting as a key element for metal homeostasis inR. leguminosarumunder free-living and symbiotic conditions. The presence of similardmeRFgene clusters in otherRhizobiaceaesuggests that thedmeRFsystem is a conserved mechanism for metal tolerance in legume endosymbiotic bacteria.

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Saïdi, Sabrine, Martha-Helena Ramírez-Bahena, Nery Santillana, Doris Zúñiga, Estela Álvarez-Martínez, Alvaro Peix, Ridha Mhamdi, and Encarna Velázquez. "Rhizobium laguerreae sp. nov. nodulates Vicia faba on several continents." International Journal of Systematic and Evolutionary Microbiology 64, Pt_1 (January 1, 2014): 242–47. http://dx.doi.org/10.1099/ijs.0.052191-0.

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Several fast-growing strains nodulating Vicia faba in Peru, Spain and Tunisia formed a cluster related to Rhizobium leguminosarum . The 16S rRNA gene sequences were identical to that of R. leguminosarum USDA 2370T, whereas rpoB, recA and atpD gene sequences were phylogenetically distant, with sequence similarities of less than 96 %, 97 % and 94 %, respectively. DNA–DNA hybridization analysis showed a mean relatedness value of 43 % between strain FB206T and R. leguminosarum USDA 2370T. Phenotypic characteristics of the novel strains also differed from those of the closest related species of the genus Rhizobium . Therefore, based on genotypic and phenotypic data obtained in this study, we propose to classify this group of strains nodulating Vicia faba as a novel species of the genus Rhizobium named Rhizobium laguerreae sp. nov. The type strain is FB206T ( = LMG 27434T = CECT 8280T).

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Cubo, Teresa, Francisco Romero, Jose M. Vinardell, and Jose E. Ruiz-Sainz. "Expression of the Rhizobium leguminosarum biovar phaseoli melA Gene in Other Rhizobia Does Not Require the Presence of the nifA Gene." Functional Plant Biology 24, no. 2 (1997): 195. http://dx.doi.org/10.1071/pp96076.

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Many different Rhizobium strains produce melanin (Mel+) when grown on solid media supplemented with L-tyrosine. The composition of the media and the culture conditions are of great importance for pigment production. Previous reports showed that some Rhizobium leguminosarum biovar phaseoli strains that produce the pigment in complete solid media (TY) failed to produce the pigment in minimal media (SY) supplemented with L-tyrosine or in TY liquid media. In this paper we have investigated different R. fredii, R. meliloti, R. etli and R. leguminosarum bv. trifolii and phaseoli strains (all of them Mel+ in solid media) for their ability to produce the pigment in liquid media. All Rhizobium species tested, except Rhizobium etli, were Mel+ in liquid media and in all cases the pigment yielded maximum absorption peaks at 280 and 315 nm. Melanin production by other bacteria (such as Vibrio, Streptomyces or Azospirillum) is enhanced by the presence of amino acids other that tyrosine. In this paper we show that the addition of L-methionine, which is not a precursor of rhizobial melanins, stimulated pigment production by Rhizobium cultures supplemented with L-tyrosine. The role of melanin production by Rhizobium strains is unclear. One hypothesis is that the Rhizobium tyrosinase, a bifunctional copper-containing enzyme that is essential for melanin biosynthesis, could detoxify polyphenolic compounds which might accumulate in senescing nodules. We show here that R. etli and R. fredii bacteroids produced melanin, which supports the idea that bacteroids contain the enzyme tyrosinase. Previous reports showed that, in R. leguminosarum bv. phaseoli strain 8002, the expression of the tyrosinase gene (melA) is dependent on the presence of nifA, a regulatory gene that is located in the symbiotic plasmid. However, transfer of R. leguminosarum bv. phaseoli melA gene to pSym-cured derivatives of R. leguminosarum bv. trifolii and viciae, R. fredii and Rhizobium sp. (Hedysarum) produced Mel+ transconjugants. DNA-hybridisation experiments showed that the pSym-cured strains did not contain any copy of nifA. Therefore, in contrast to the results reported on R. leguminosarum bv. phaseoli strain 8002, the expression of the melA gene in other rhizobia is not nifA-dependent. Key words: Rhizobium, melanin.

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Krugova, O. D., and N. M. Mandrovskaya. "THE NODULATION COMPETITIVENESS OF TN5-MUTANTS RHIZOBIUM LEGUMINOSARUM BV. VICIAE." Agriciltural microbiology 6 (February 20, 2008): 18–28. http://dx.doi.org/10.35868/1997-3004.6.18-28.

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There has been studied the nodulation competitiveness of Tn5 mutants of pea rhizobia which were obtained from Rhizobium leguminosarum bv. viciae 263 б and which had high nitrogen fixing activity and promoted the increase of both nodule number and aboveground biomass in comparison with wild strains. It was shown that the competition ability of M1 and М68 mutants did not differ from the competitive ability of strains 263 б and Rhizobium leguminosarum bv. viciae 245 a of industrial strains.

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García-de los Santos, Alejandro, Alejandro Morales, Laura Baldomá, Scott R. D. Clark, Susana Brom, Christopher K. Yost, Ismael Hernández-Lucas, Juan Aguilar, and Michael F. Hynes. "TheglcBlocus ofRhizobium leguminosarumVF39 encodes an arabinose-inducible malate synthase." Canadian Journal of Microbiology 48, no. 10 (October 1, 2002): 922–32. http://dx.doi.org/10.1139/w02-091.

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In the course of a study conducted to isolate genes upregulated by plant cell wall sugars, we identified an arabinose-inducible locus from a transcriptional fusion library of Rhizobium leguminosarum VF39, carrying random insertions of the lacZ transposon Tn5B22. Sequence analysis of the locus disrupted by the transposon revealed a high similarity to uncharacterized malate synthase G genes from Sinorhizobium meliloti, Agrobacterium tumefaciens, and Mesorhizobium loti. This enzyme catalyzes the condensation of glyoxylate and acetyl-CoA to yield malate and CoA and is thought to be a component of the glyoxylate cycle, which allows microorganisms to grow on two carbon compounds. Enzyme assays showed that a functional malate synthase is encoded in the glcB gene of R. leguminosarum and that its expression is induced by arabinose, glycolate, and glyoxylate. An Escherichia coli aceB glcB mutant, complemented with the R. leguminosarum PCR-amplified gene, recovered malate synthase activity. A very similar genome organization of the loci containing malate synthase and flanking genes was observed in R. leguminosarum, S. meliloti, and A. tumefaciens. Pea plants inoculated with the glcB mutant or the wild-type strain showed no significant differences in nitrogen fixation. This is the first report regarding the characterization of a mutant in one of the glyoxylate cycle enzymes in the rhizobia.Key words: Rhizobium, malate synthase, glyoxylate cycle, arabinose metabolism.

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Knee, Emma M., Fang-Chen Gong, Mensheng Gao, Max Teplitski, Angela R. Jones, Angel Foxworthy, Andrew J. Mort, and Wolfgang D. Bauer. "Root Mucilage from Pea and Its Utilization by Rhizosphere Bacteria as a Sole Carbon Source." Molecular Plant-Microbe Interactions® 14, no. 6 (June 2001): 775–84. http://dx.doi.org/10.1094/mpmi.2001.14.6.775.

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Plant roots secrete a complex polysaccharide mucilage that may provide a significant source of carbon for microbes that colonize the rhizosphere. High molecular weight mucilage was separated by high-pressure liquid chromatography gel filtration from low molecular weight components of pea root exudate. Purified pea root mucilage generally was similar in sugar and glycosidic linkage composition to mucilage from cowpea, wheat, rice, and maize, but appeared to contain an unusually high amount of material that was similar to arabinogalactan protein. Purified pea mucilage was used as the sole carbon source for growth of several pea rhizosphere bacteria, including Rhizobium leguminosarum 8401 and 4292, Burkholderia cepacia AMMD, and Pseudomonas fluorescens PRA25. These species grew on mucilage to cell densities of three- to 25-fold higher than controls with no added carbon source, with cell densities of 1 to 15% of those obtained on an equal weight of glucose. Micromolar concentrations of nod gene-inducing flavonoids specifically stimulated mucilage-dependent growth of R. leguminosarum 8401 to levels almost equaling the glucose controls. R. leguminosarum 8401 was able to hydrolyze p-nitrophenyl glycosides of various sugars and partially utilize a number of purified plant polysaccharides as sole carbon sources, indicating that R. leguminosarum 8401 can make an unexpected variety of carbohydrases, in accordance with its ability to extensively utilize pea root mucilage.

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Trinick, Michael J., Celia Miller, and Paul A. Hadobas. "Formation and structure of root nodules induced on Macroptilium atropurpureum inoculated with various species of Rhizobium." Canadian Journal of Botany 69, no. 7 (July 1, 1991): 1520–32. http://dx.doi.org/10.1139/b91-196.

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Fifteen strains of Rhizobium leguminosarum biovar trifolii formed ineffective nodules and (or) nodule-like structures (rhizobia were re-isolated from both structures) on Macroptilium atropurpureum grown in enclosed glass tubes. Bacteria were observed among the parenchyma cells surrounding the nodule-like structures. One variant of R. leguminosarum biovar trifolii (NGR66/ST) isolated from M. atropurpureum formed nodules on this host that exhibited abnormal intercellular and intracellular infection. The bacteria (NGR66/ST) were contained within threadlike structures, surrounded by matrix material. The identities of the Rhizobium strains were confirmed serologically after reisolation and in sections of nodule tissue using immunogold labelling. Rhizobium leguminosarum biovar phaseoli strain NGR76 isolated from Phaseolus vulgaris formed nodules on M. atropurpureum resembling those formed by effective Bradyrhizobium strains. The association was partially effective in nitrogen fixation, and this was reflected in the nodule structure. The percentage of cells infected was lower than that in fully effective nodules. There was a high frequency of infected cells showing degeneration; these were located throughout the nodule tissue and were often adjacent to healthy infected cells. The rhizobia appeared to infect new nodule cells via infection threads, which were abundant both intercellularly and intracellularly in young, mature, and degenerating host nodule cells. Strains of R. leguminosarum biovar viceae and Rhizobium meliloti were unable to induce nodule-like structures on M. atropurpureum. Key words: Macroptilium, Bradyrhizobium, Rhizobium, microscopy, nodule, structure.

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RENNIE, R. J., R. J. HOWARD, T. A. SWANSON, and G. H. A. FLORES. "THE EFFECT OF SEED-APPLIED PESTICIDES ON GROWTH AND N2 FIXATION IN PEA, LENTIL, AND FABABEAN." Canadian Journal of Plant Science 65, no. 1 (January 1, 1985): 23–28. http://dx.doi.org/10.4141/cjps85-003.

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Conflicting recommendations exist on the effect of seed-applied pesticides on nodulation and N2 fixation by Rhizobium leguminosarum. This paper reports the effects of captan, thiram, metalaxyl, Evershield, DL-PLUS® and B-3 in a 2-yr field experiment on emergence, nodulation, acetylene-reducing activity, and shoot yield of pea (Pisum sativum L.), lentil (Lens culinaris L.), and fababean (Vicia faba L.) inoculated with seed-applied R. leguminosarum multi-strain inoculum. Seedling emergence was not detrimentally affected by pesticide application. While most of the pesticides had either stimulatory or minimally detrimental effects on nodulation and nitrogenase activity, captan reduced both in all three legumes. Captan-containing compounds such as B-3 (33.5% captan) and Evershield (29.5% captan) also reduced nodulation or nitrogenase activity in some of these legumes. DL-PLUS (15% captan) was not harmful, which suggests that compounds containing over 29.5% captan may not be compatible with seed-applied R. leguminosarum. Captan, which was consistently harmful, is considered the best wide-spectrum pesticide for use with these legumes. Thus, it will be necessary to select superior N2-fixing strains of R. leguminosarum that are tolerant of, if not resistant to, recommended rates of captan or to identify alternate pesticides that are more compatible with rhizobia.Key words: Captan, thiram, metalaxyl, Evershield, DL-PLUS, B-3

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41

Gawryjołek, Karolina, Karolina Furtak, Jarosław Grządziel, and Anna Gałązka. "Identification and Characterization of Metabolic Potential of Different Strains from Genus Rhizobium." Proceedings 66, no. 1 (January 8, 2021): 19. http://dx.doi.org/10.3390/proceedings2020066019.

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Bacteria of the Rhizobium genus form a group of microorganisms existing in the environment in two forms: symbiotic, in the root nodules of Fabaceae sp. plants and free-living, and saprophytic in the soil environment. The subject of this study was genetic identification and characterization of metabolic activity of different strains from Rhizobium genus bacteria. The study was conducted on the 16 bacteria strains from the collection of the Department of Agricultural Microbiology, Institute of Soil Science and Plant Cultivation in Puławy, Poland. Based on the sequencing of PCR products, we found that all strains belong to one species—Rhizobium leguminosarum. The study of metabolic activity was performed using the GEN III BIOLOG system method (Biolog Inc., Hayward, CA, USA). Metabolism analysis of all R. leguminosarum strains with the use of GEN III™ plates showed that carbohydrates (CH) were the most intensively utilised group of substrates. Between the Rhizobium leguminosarum strains, there are metabolic differences in terms of the studied features.

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42

Gawryjołek, Karolina, Karolina Furtak, Jarosław Grządziel, and Anna Gałązka. "Identification and Characterization of Metabolic Potential of Different Strains from Genus Rhizobium." Proceedings 66, no. 1 (January 8, 2021): 19. http://dx.doi.org/10.3390/proceedings2020066019.

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Анотація:

Bacteria of the Rhizobium genus form a group of microorganisms existing in the environment in two forms: symbiotic, in the root nodules of Fabaceae sp. plants and free-living, and saprophytic in the soil environment. The subject of this study was genetic identification and characterization of metabolic activity of different strains from Rhizobium genus bacteria. The study was conducted on the 16 bacteria strains from the collection of the Department of Agricultural Microbiology, Institute of Soil Science and Plant Cultivation in Puławy, Poland. Based on the sequencing of PCR products, we found that all strains belong to one species—Rhizobium leguminosarum. The study of metabolic activity was performed using the GEN III BIOLOG system method (Biolog Inc., Hayward, CA, USA). Metabolism analysis of all R. leguminosarum strains with the use of GEN III™ plates showed that carbohydrates (CH) were the most intensively utilised group of substrates. Between the Rhizobium leguminosarum strains, there are metabolic differences in terms of the studied features.

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43

Josic, Dragana, Bogic Milicic, Snezana Mladenovic-Drinic, and Mirjana Jarak. "Genodiversity of dominant Rhizobium leguminosarum bv. Trifolii isolated from 11 types of soil in Serbia." Genetika 40, no. 2 (2008): 179–90. http://dx.doi.org/10.2298/gensr0802179j.

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Rhizobium leguminosarum bv. trifolii is microsymbiont Trifolium pratense and Trifolium repens, which are very important legumes in Serbia. The natural nodulating population of those bacteria was collected and estimated biodiversity distribution by monitoring dominant genotypes of these bacteria. The population of Rhizobium leguminosarum bv. trifolii were collected from 50 marked locations of 11 types of soil in Serbia. 437 natural isolates, rescued from nodules of Trifolium repens or Trifolium pratense, were analyzed by phenotypic approach. We obtained 156 different isolates on the basis of differences in their IAR - intrinsic antibiotic resistance (five antibiotics) and HMT- heavy methal tolerance (five heavy metals). We investigated 56 dominant isolates with more than three differences in IAR-HMT patterns by REP-PCR and RAPD fingerprinting (AP10 and SPH 1 primers). The results showed genodiversity of dominant Rhizobium leguminosarum bv. trifolii field isolates and offered the possibility to assess their changes on marked locations during time and under different environmental conditions and geographical distribution.

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44

Karunakaran, Ramakrishnan, Andreas F. Haag, Alison K. East, Vinoy K. Ramachandran, Jurgen Prell, Euan K. James, Marco Scocchi, Gail P. Ferguson, and Philip S. Poole. "BacA Is Essential for Bacteroid Development in Nodules of Galegoid, but not Phaseoloid, Legumes." Journal of Bacteriology 192, no. 11 (April 2, 2010): 2920–28. http://dx.doi.org/10.1128/jb.00020-10.

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ABSTRACT BacA is an integral membrane protein, the mutation of which leads to increased resistance to the antimicrobial peptides bleomycin and Bac71-35 and a greater sensitivity to SDS and vancomycin in Rhizobium leguminosarum bv. viciae, R. leguminosarum bv. phaseoli, and Rhizobium etli. The growth of Rhizobium strains on dicarboxylates as a sole carbon source was impaired in bacA mutants but was overcome by elevating the calcium level. While bacA mutants elicited indeterminate nodule formation on peas, which belong to the galegoid tribe of legumes, bacteria lysed after release from infection threads and mature bacteroids were not formed. Microarray analysis revealed almost no change in a bacA mutant of R. leguminosarum bv. viciae in free-living culture. In contrast, 45 genes were more-than 3-fold upregulated in a bacA mutant isolated from pea nodules. Almost half of these genes code for cell membrane components, suggesting that BacA is crucial to alterations that occur in the cell envelope during bacteroid development. In stark contrast, bacA mutants of R. leguminosarum bv. phaseoli and R. etli elicited the formation of normal determinate nodules on their bean host, which belongs to the phaseoloid tribe of legumes. Bacteroids from these nodules were indistinguishable from the wild type in morphology and nitrogen fixation. Thus, while bacA mutants of bacteria that infect galegoid or phaseoloid legumes have similar phenotypes in free-living culture, BacA is essential only for bacteroid development in indeterminate galegoid nodules.

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Wilkinson, A., V. Danino, F. Wisniewski-Dyé, J. K. Lithgow, and J. A. Downie. "N-Acyl-Homoserine Lactone Inhibition of Rhizobial Growth Is Mediated by Two Quorum-Sensing Genes That Regulate Plasmid Transfer." Journal of Bacteriology 184, no. 16 (August 15, 2002): 4510–19. http://dx.doi.org/10.1128/jb.184.16.4510-4519.2002.

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ABSTRACT The growth of some strains of Rhizobium leguminosarum bv. viciae is inhibited by N-(3-hydroxy-7-cis tetradecenoyl)-l-homoserine lactone (3OH-C14:1-HSL), which was previously known as the small bacteriocin before its characterization as an N-acyl homoserine lactone (AHL). Tn5-induced mutants of R. leguminosarum bv. viciae resistant to 3OH-C14:1-HSL were isolated, and mutations in two genes were identified. These genes, bisR and triR, which both encode LuxR-type regulators required for plasmid transfer, were found downstream of an operon containing trb genes involved in the transfer of the symbiotic plasmid pRL1JI. The first gene in this operon is traI, which encodes an AHL synthase, and the trbBCDEJKLFGHI genes were found between traI and bisR. Mutations in bisR, triR, traI, or trbL blocked plasmid transfer. Using gene fusions, it was demonstrated that bisR regulates triR in response to the presence of 3OH-C14:1-HSL. In turn, triR is then required for the induction of the traI-trb operon required for plasmid transfer. bisR also represses expression of cinI, which is chromosomally located and determines the level of production of 3OH-C14:1-HSL. The cloned bisR and triR genes conferred 3OH-C14:1-HSL sensitivity to strains of R. leguminosarum bv. viciae normally resistant to this AHL. Furthermore, bisR and triR made Agrobacterium tumefaciens sensitive to R. leguminosarum bv. viciae strains producing 3OH-C14:1-HSL. Analysis of patterns of growth inhibition using mutant strains and synthetic AHLs revealed that maximal growth inhibition required, in addition to 3OH-C14:1-HSL, the presence of other AHLs such as N-octanoyl-l-homoserine lactone and/or N-(3-oxo-octanoyl)-l-homoserine lactone. In an attempt to identify the causes of growth inhibition, a strain of R. leguminosarum bv. viciae carrying cloned bisR and triR was treated with an AHL extract containing 3OH-C14:1-HSL. N-terminal sequencing of induced proteins revealed one with significant similarity to the protein translation factor Ef-Ts.

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46

Young, J. Peter W., Sara Moeskjær, Alexey Afonin, Praveen Rahi, Marta Maluk, Euan K. James, Maria Izabel A. Cavassim, et al. "Defining the Rhizobium leguminosarum Species Complex." Genes 12, no. 1 (January 18, 2021): 111. http://dx.doi.org/10.3390/genes12010111.

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Bacteria currently included in Rhizobium leguminosarum are too diverse to be considered a single species, so we can refer to this as a species complex (the Rlc). We have found 429 publicly available genome sequences that fall within the Rlc and these show that the Rlc is a distinct entity, well separated from other species in the genus. Its sister taxon is R. anhuiense. We constructed a phylogeny based on concatenated sequences of 120 universal (core) genes, and calculated pairwise average nucleotide identity (ANI) between all genomes. From these analyses, we concluded that the Rlc includes 18 distinct genospecies, plus 7 unique strains that are not placed in these genospecies. Each genospecies is separated by a distinct gap in ANI values, usually at approximately 96% ANI, implying that it is a ‘natural’ unit. Five of the genospecies include the type strains of named species: R. laguerreae, R. sophorae, R. ruizarguesonis, “R. indicum” and R. leguminosarum itself. The 16S ribosomal RNA sequence is remarkably diverse within the Rlc, but does not distinguish the genospecies. Partial sequences of housekeeping genes, which have frequently been used to characterize isolate collections, can mostly be assigned unambiguously to a genospecies, but alleles within a genospecies do not always form a clade, so single genes are not a reliable guide to the true phylogeny of the strains. We conclude that access to a large number of genome sequences is a powerful tool for characterizing the diversity of bacteria, and that taxonomic conclusions should be based on all available genome sequences, not just those of type strains.

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47

Poole, Philip, Colm Reid, Alison K. East, David Allaway, Michael Day, and Mary Leonard. "Regulation of themdh-sucCDABoperon inRhizobium leguminosarum." FEMS Microbiology Letters 176, no. 1 (July 1999): 247–55. http://dx.doi.org/10.1111/j.1574-6968.1999.tb13669.x.

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Al-Hamdany, Mouhamed, and Mohamed M. Salih. "Leveillula leguminosarum on alfalfa in Iraq." Transactions of the British Mycological Society 84, no. 2 (March 1985): 338–40. http://dx.doi.org/10.1016/s0007-1536(85)80087-5.

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49

Raaman, N., B. Mahendran, C. Jaganathan, S. Sukumar, and V. Chandrasekaran. "Removal of chromium using Rhizobium leguminosarum." World Journal of Microbiology and Biotechnology 28, no. 2 (August 25, 2011): 627–36. http://dx.doi.org/10.1007/s11274-011-0856-6.

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50

Nečásek, J., M. Němcová, L. Lisá, J. Dusbábková, V. Našinec, and D. Požárková. "Drought tolerance ofRhizobium leguminosarum andR. meliloti." Folia Microbiologica 38, no. 4 (August 1993): 320–24. http://dx.doi.org/10.1007/bf02898601.

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