Journal articles on the topic 'Rhizobium'
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1
SHAHRAJABIAN, Mohamad H., Wenli SUN, and Qi CHENG. "The importance of Rhizobium, Agrobacterium, Bradyrhizobium, Herbaspirillum, Sinorhizobium in sustainable agricultural production." Notulae Botanicae Horti Agrobotanici Cluj-Napoca 49, no. 3 (September 10, 2021): 12183. http://dx.doi.org/10.15835/nbha49312183.
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Rhizobia which are soil bacteria capable of symbiosis with legume plants in the root or stem nodules and perform nitrogen fixation. Rhizobial genera include Agrobacterium, Allorhizobium, Aminobacter, Azorhizobium, Bradyrhizobium, Devosia, Mesorhizobium, Methylobacterium, Microvirga, Ochrobacterum, Phyllobacterium, Rhizobium, Shinella and Ensifer (Sinorhizobium). Review of the literature was carried out using the keywords Rhizobium, Agrobacterium, Bradyrhizobium, Herbaspirillum and Sinorhizobium. Rhizobial nodulation symbioses steps are included flavonoid signaling, Nod factor induction, and Nod factor perception, root hair responses, rhizobial infection, cell division and formation of nitrogen-fixing nodule. Rhizobium improves sustainable production by boosting organic nitrogen content.
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Op den Camp, Rik H. M., Elisa Polone, Elena Fedorova, Wim Roelofsen, Andrea Squartini, Huub J. M. Op den Camp, Ton Bisseling, and René Geurts. "Nonlegume Parasponia andersonii Deploys a Broad Rhizobium Host Range Strategy Resulting in Largely Variable Symbiotic Effectiveness." Molecular Plant-Microbe Interactions® 25, no. 7 (July 2012): 954–63. http://dx.doi.org/10.1094/mpmi-11-11-0304.
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The non-legume genus Parasponia has evolved the rhizobium symbiosis independent from legumes and has done so only recently. We aim to study the promiscuity of such newly evolved symbiotic engagement and determine the symbiotic effectiveness of infecting rhizobium species. It was found that Parasponia andersonii can be nodulated by a broad range of rhizobia belonging to four different genera, and therefore, we conclude that this non-legume is highly promiscuous for rhizobial engagement. A possible drawback of this high promiscuity is that low-efficient strains can infect nodules as well. The strains identified displayed a range in nitrogen-fixation effectiveness, including a very inefficient rhizobium species, Rhizobium tropici WUR1. Because this species is able to make effective nodules on two different legume species, it suggests that the ineffectiveness of P. andersonii nodules is the result of the incompatibility between both partners. In P. andersonii nodules, rhizobia of this strain become embedded in a dense matrix but remain vital. This suggests that sanctions or genetic control against underperforming microsymbionts may not be effective in Parasponia spp. Therefore, we argue that the Parasponia-rhizobium symbiosis is a delicate balance between mutual benefits and parasitic colonization.
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NISTE, Monica, Roxana VIDICAN, Ioan ROTAR, and Rodica POP. "The Effect of pH Stress on the Survival of Rhizobium Trifolii and Sinorhizobium Meliloti in Vitro." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 70, no. 2 (November 26, 2013): 449–50. http://dx.doi.org/10.15835/buasvmcn-agr:9811.
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Nitrogen-fixing symbiotic bacteria known as rhizobia can exist in different soils and adapt to different environmental conditions. The aim of this study was to determine the impact of pH on the growth of Rhizobium trifolii and Sinorhizobium meliloti. Rhizobial species were isolated using yeast extract mannitol agar medium) in which the pH values were adjusted to 5.0, 6.0, 8.0 and 9.0 by adding HCl and NaOH. The optimum pH for rhizobia is neutral or slightly alkaline (pH 8) and they are more sensitive to acidity. Sinorhizobium meliloti developed better in an acid medium compared to Rhizobium trifolii.
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Aguilar, O. Mario, María Verónica López, Pablo M. Riccillo, Ramón A. González, Marcela Pagano, Daniel H. Grasso, Alfred Pühler, and Gabriel Favelukes. "Prevalence of the Rhizobium etli-Like Allele in Genes Coding for 16S rRNA among the Indigenous Rhizobial Populations Found Associated with Wild Beans from the Southern Andes in Argentina." Applied and Environmental Microbiology 64, no. 9 (September 1, 1998): 3520–24. http://dx.doi.org/10.1128/aem.64.9.3520-3524.1998.
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ABSTRACT A collection of rhizobial isolates from nodules of wild beans,Phaseolus vulgaris var. aborigineus, found growing in virgin lands in 17 geographically separate sites in northwest Argentina was characterized on the basis of host range, growth, hybridization to a nifH probe, analysis of genes coding for 16S rRNA (16S rDNA), DNA fingerprinting, and plasmid profiles. Nodules in field-collected wild bean plants were largely dominated by rhizobia carrying the 16S rDNA allele of Rhizobium etli. A similar prevalence of the R. etli allele was observed among rhizobia trapped from nearby soil. Intragroup diversity of wild bean isolates with either R. etli-like or Rhizobium leguminosarum bv. phaseoli-like alleles was generally found across northwest Argentina. The predominance of the R. etliallele suggests that in this center of origin of P. vulgaris the coevolution of Rhizobium spp. and primitive beans has resulted in this preferential symbiotic association.
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Mendoza-Suárez, Marcela A., Barney A. Geddes, Carmen Sánchez-Cañizares, Ricardo H. Ramírez-González, Charlotte Kirchhelle, Beatriz Jorrin, and Philip S. Poole. "Optimizing Rhizobium-legume symbioses by simultaneous measurement of rhizobial competitiveness and N2 fixation in nodules." Proceedings of the National Academy of Sciences 117, no. 18 (April 21, 2020): 9822–31. http://dx.doi.org/10.1073/pnas.1921225117.
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Legumes tend to be nodulated by competitive rhizobia that do not maximize nitrogen (N2) fixation, resulting in suboptimal yields. Rhizobial nodulation competitiveness and effectiveness at N2 fixation are independent traits, making their measurement extremely time-consuming with low experimental throughput. To transform the experimental assessment of rhizobial competitiveness and effectiveness, we have used synthetic biology to develop reporter plasmids that allow simultaneous high-throughput measurement of N2 fixation in individual nodules using green fluorescent protein (GFP) and barcode strain identification (Plasmid ID) through next generation sequencing (NGS). In a proof-of-concept experiment using this technology in an agricultural soil, we simultaneously monitored 84 different Rhizobium leguminosarum strains, identifying a supercompetitive and highly effective rhizobial symbiont for peas. We also observed a remarkable frequency of nodule coinfection by rhizobia, with mixed occupancy identified in ∼20% of nodules, containing up to six different strains. Critically, this process can be adapted to multiple Rhizobium-legume symbioses, soil types, and environmental conditions to permit easy identification of optimal rhizobial inoculants for field testing to maximize agricultural yield.
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ZAMAN-ALLAH, M., B. SIFI, B. L'TAIEF, M. H. EL AOUNI, and J. J. DREVON. "RHIZOBIAL INOCULATION AND P FERTILIZATION RESPONSE IN COMMON BEAN (PHASEOLUS VULGARIS) UNDER GLASSHOUSE AND FIELD CONDITIONS." Experimental Agriculture 43, no. 1 (January 2007): 67–77. http://dx.doi.org/10.1017/s0014479706004236.
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Osmotic constraints, nutrient deficiencies, especially phosphorus, and the lack of efficient strains of rhizobia in Mediterranean soils are major factors limiting symbiotic nitrogen fixation and yield in common bean (Phaseolus vulgaris). In order to improve yields, we investigated responses to rhizobial inoculation and P fertilization under glasshouse and field conditions with two bean cultivars, Coco blanc and BAT477. The nodulation test, using a hydroponic system in a glasshouse, revealed strong variability among 22 rhizobium strains of various origins, in their symbiotic efficiency, compared with Rhizobium tropici CIAT899. The introduced strains proved to be more efficient although some local rhizobia revealed high potential efficiencies. Glasshouse trials showed a significant effect of inoculation and P supply on nodulation, N content and shoot dry weight that varied with rhizobial strain. Field trials substantiated the glasshouse observations and emphasized the effects of cultivar-rhizobia interactions on symbiotic parameters and yields. It is concluded that inoculation with suitable rhizobia with supply of additional P is a technology that may improve symbiotic nitrogen fixation and yield in common bean in some soils under a Mediterranean climate.
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Milićević, Milica, Dušica Delić, Nataša Rasulić, Mila Pešić, Merisa Avdović, Olivera Stajković-Srbinović, and Biljana Nikolić. "Production of indolic compounds by rhizobial bacteria." Zemljiste i biljka 72, no. 2 (2023): 48–59. http://dx.doi.org/10.5937/zembilj2302048m.
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Rhizobial bacteria, besides nitrogen fixation in symbiosis with legumes, can colonize the roots of nonlegumes and promote their growth by different mechanisms, independently of N2 fixation. Owing to this, rhizobia are considered a plant growth-promoting rhizobacteria (PGPR). Some of the mechanisms of PGPR activity are phytohormone production. Selection of rhizobia which possess some of PGP traits in vitro is an important step prior to testing their effects on plants in controlled conditions or field. In this work the ability of indole-3-acid (IAA) production, one of the most important phytohormone of the auxin class, was evaluated in different rhizobial strains. The investigated rhizobial strains were isolated from alfalfa (belonged to the genera Ensifer and Rhizobium) and from soybean (Bradyrhizobium and Rhizobium). Strains of all investigated genera produced IAA in the presence of L-tryptophan as precursor, where Ensifer strains produced the highest amount of IAA (more than 200 µg ml-1 ), followed by Rhizobium, while Bradyrhizobium strains produced the least amount of IAA (with some exceptions up to 15 µg ml-1 ). With the increase of L-tryptophan concentration, the amount of IAA produced usually grew. Strains with high IAA production indicate their plant growth promoting potential and represent the candidates for evaluation of their effects in non-legumes in controlled and field conditions.
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Mateos, Pedro F., David L. Baker, Maureen Petersen, Encarna Velázquez, José I. Jiménez-Zurdo, Eustoquio Martínez-Molina, Andrea Squartini, Guy Orgambide, David H. Hubbell, and Frank B. Dazzo. "Erosion of root epidermal cell walls by Rhizobium polysaccharide-degrading enzymes as related to primary host infection in the Rhizobiumlegume symbiosis." Canadian Journal of Microbiology 47, no. 6 (June 1, 2001): 475–87. http://dx.doi.org/10.1139/w01-039.
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A central event of the infection process in the Rhizobiumlegume symbiosis is the modification of the host cell wall barrier to form a portal of entry large enough for bacterial penetration. Transmission electron microscopy (TEM) indicates that rhizobia enter the legume root hair through a completely eroded hole that is slightly larger than the bacterial cell and is presumably created by localized enzymatic hydrolysis of the host cell wall. In this study, we have used microscopy and enzymology to further clarify how rhizobia modify root epidermal cell walls to shed new light on the mechanism of primary host infection in the Rhizobiumlegume symbiosis. Quantitative scanning electron microscopy indicated that the incidence of highly localized, partially eroded pits on legume root epidermal walls that follow the contour of the rhizobial cell was higher in host than in nonhost legume combinations, was inhibited by high nitrate supply, and was not induced by immobilized wild-type chitolipooligosaccharide Nod factors reversibly adsorbed to latex beads. TEM examination of these partially eroded, epidermal pits indicated that the amorphous, noncrystalline portions of the wall were disrupted, whereas the crystalline portions remained ultrastructurally intact. Further studies using phase-contrast and polarized light microscopy indicated that (i) the structural integrity of clover root hair walls is dependent on wall polymers that are valid substrates for cell-bound polysaccharide-degrading enzymes from rhizobia, (ii) the major site where these rhizobial enzymes can completely erode the root hair wall is highly localized at the isotropic, noncrystalline apex of the root hair tip, and (iii) the degradability of clover root hair walls by rhizobial polysaccharide-degrading enzymes is enhanced by modifications induced during growth in the presence of chitolipooligosaccharide Nod factors from wild-type clover rhizobia. The results suggest a complementary role of rhizobial cell-bound glycanases and chitolipooligosaccharides in creating the localized portals of entry for successful primary host infection.Key words: Rhizobium leguminosarum, cellulase, cell wall, chitolipooligosaccharide, clover, root hair.
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Materon, L. A., J. D. H. Keatinge, D. P. Beck, N. Yurtsever, K. Karuc, and S. Altuntas. "The Role of Rhizobial Biodiversity in Legume Crop Productivity in the West Asian Highlands." Experimental Agriculture 31, no. 4 (October 1995): 485–91. http://dx.doi.org/10.1017/s0014479700026466.
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SUMMARYThe native rhizobia capable of symbiosis with annually-sown food and forage legume crops in the Turkish highlands were surveyed and estimates made of the numbers and nitrogen fixing efficiency of native Rhizobium leguminosarum with Turkish cultivars of lentil (Lens culinaris Medik.) and vetch (Vicia sativa L.). Native rhizobia were present in medium to high numbers in most samples but the nitrogen fixation efficiency of at least half of the isolates was poor. Vetch was somewhat less specific in its rhizobial compatibility than lentil, suggesting a potential for artificial inoculation to improve the productivity and sustainability of cropping in both species especially in areas of central and eastern Anatolia where legumes are not traditionally grown.Biodiversidad en el Rhizobium leguminosarum
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Castellano-Hinojosa, Antonio, Christoph Mora, and Sarah L. Strauss. "Native Rhizobia Improve Plant Growth, Fix N2, and Reduce Greenhouse Emissions of Sunnhemp More than Commercial Rhizobia Inoculants in Florida Citrus Orchards." Plants 11, no. 22 (November 8, 2022): 3011. http://dx.doi.org/10.3390/plants11223011.
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Sunnhemp (Crotalaria juncea L.) is an important legume cover crop used in tree cropping systems, where there is increased interest by growers to identify rhizobia to maximize soil nitrogen (N) inputs. We aimed to isolate and identify native rhizobia and compare their capabilities with non-native rhizobia from commercial inoculants to fix atmospheric dinitrogen (N2), produce and reduce nitrous oxide (N2O), and improve plant growth. Phylogenetic analyses of sequences of the 16S rRNA and recA, atpD, and glnII genes showed native rhizobial strains belonged to Rhizobium tropici and the non-native strain to Bradyrhizobium japonicum. Plant nodulation tests, sequencing of nodC and nifH genes, and the acetylene-dependent ethylene production assay confirmed the capacity of all strains to nodulate sunnhemp and fix N2. Inoculation with native rhizobial strains resulted in significant increases in root and shoot weight and total C and N contents in the shoots, and showed greater N2-fixation rates and lower emissions of N2O compared to the non-native rhizobium. Our results suggest that native rhizobia improve plant growth, fix N2, and reduce greenhouse emissions of sunnhemp more than commercial rhizobia inoculants in Florida citrus orchards.
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Kyei-Boahen, S., A. E. Slinkard, and F. L. Walley. "Rhizobial survival and nodulation of chickpea as influenced by fungicide seed treatment." Canadian Journal of Microbiology 47, no. 6 (June 1, 2001): 585–89. http://dx.doi.org/10.1139/w01-038.
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The survival of Rhizobium ciceri on chickpea (Cicer arietinum cv. Myles) seed, treated separately with 1 of 4 commercial fungicides, i.e., Apron®, Arrest 75W®, Crown®, or Captan®, was examined under laboratory conditions using standard serial dilution and plate count techniques. The resulting effects of fungicideRhizobium interactions on nodulation, N2 fixation, and plant growth were assessed in a controlled environment. Fungicide treatment decreased the number of viable rhizobia on the seed. In general, the toxicity of the fungicides in terms of rhizobial viability increased in the following order: Control = Crown < Arrest = Apron < Captan. Although Crown had no effect on rhizobial viability assessed under laboratory conditions, it significantly reduced nodulation, percent N derived from the atmosphere (%Ndfa), and shoot dry matter. Seed treated with Arrest and Captan decreased nodule dry weight and %Ndfa, but only Arrest reduced dry matter yield. Apron had no effect on any of the parameters measured at the early pod-filling stage and was compatible with the chickpea inoculum used in this study.Key words: fungicides, Rhizobium ciceri, inoculation, nodulation, chickpea, Cicer arietinum.
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Velázquez, Encarna, Esperanza Martı́nez-Romero, Dulce Nombre Rodrı́guez-Navarro, Martha E. Trujillo, Antonio Daza, Pedro F. Mateos, Eustoquio Martı́nez-Molina, and Peter van Berkum. "Characterization of Rhizobial Isolates of Phaseolus vulgaris by Staircase Electrophoresis of Low-Molecular-Weight RNA." Applied and Environmental Microbiology 67, no. 2 (February 1, 2001): 1008–10. http://dx.doi.org/10.1128/aem.67.2.1008-1010.2001.
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ABSTRACT Low-molecular-weight (LMW) RNA molecules were analyzed to characterize rhizobial isolates that nodulate the common bean growing in Spain. Since LMW RNA profiles, determined by staircase electrophoresis, varied across the rhizobial species nodulating beans, we demonstrated that bean isolates recovered from Spanish soils presumptively could be characterized as Rhizobium etli,Rhizobium gallicum, Rhizobium giardinii,Rhizobium leguminosarum bv. viciae and bv. trifolii, andSinorhizobium fredii.
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Thiagarajan, T. R., R. N. Ames, and M. H. Ahmad. "Response of cowpea (Vigna unguiculata) to inoculation with co-selected vesicular–arbuscular mycorrhizal fungi and Rhizobium strains in field trials." Canadian Journal of Microbiology 38, no. 6 (June 1, 1992): 573–76. http://dx.doi.org/10.1139/m92-094.
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After initial screening in sterilized and nonsterilized soils, two vesicular–arbuscular mycorrhizal (VAM) fungi (Glomus pallidum Hall and Sclerocystis microcarpa Iqbal & Bushra) and two compatible cowpea rhizobial strains (JRC14 and JRC29) have been co-selected. The response of cowpea (Vigna unguiculata (L.) Walp) to inoculation with co-selected pairs of VAM fungus and Rhizobium strains was field tested in Jamaica at two locations (soil types sandy clay loam and bauxitic silt loam). Dual inoculations of cowpea increased the pod yield, mycorrhizal infection, nodule formation, and shoot P and N content compared with single inoculations of either VAM fungus or Rhizobium. However, JRC14 when paired with G. pallidum or S. microcarpa showed maximum yield increase (45%) in both soil types. Our work suggests that appropriate pairing of VAM fungus – Rhizobium should be used for field inoculation. Key words: cowpea, rhizobia, mycorrhizal fungi.
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Tanim, Md Tauhidul Islam, Md Miraj Kobad Chowdhury, Latiful Bari, Md Mizanur Rahaman, Sabita Rezwana Rahman, and Md Majibur Rahman. "Genetic diversity of Rhizobium spp. isolated from soil samples of Bangladesh." Bangladesh Journal of Microbiology 36, no. 1 (December 8, 2019): 7–10. http://dx.doi.org/10.3329/bjm.v36i1.44261.
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Rhizobia are Gram-negative soil-inhabiting bacteria commonly found in nodules of leguminous plants. These bacteria exclusively fix atmospheric nitrogen into ammonia, which is convertible to urea to serve natural fertilizer to the plants. However, rhizobial microbiota of Bangladesh have been studied poorly. Here, twenty isolates were identified as Rhizobium through observation of cultural characteristics, morphological characteristics and different biochemical tests. Isolates differed from one another in terms of their stress response characteristics like salt-stress tolerance,temperature tolerance, antibiotic susceptibility, and pH. Most of the isolates were resistant to ampicillin and erythromycin and streptomycin; and were sensitive to kanamycin and ciprofloxacin. Isolates were clustered into three genotypic groups according to the banding patterns of Amplified Ribosomal DNA Restriction Analysis (ARDRA). All the strains in ARDRA group 1 were Rhizobium azibense, and the others were Rhizobium bangladeshense and Rhizobium qilianshanense. Future studies would validate their capacity of nitrogen fixation and the scope of improvement of these strains to increase their efficiency of nitrogen fixation.
Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 07-10
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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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Olsen, Perry E., Wendell A. Rice, Lucien M. Bordeleau, A. H. Demidoff, and Mandy M. Collins. "Levels and identities of nonrhizobial microorganisms found in commercial legume inoculant made with nonsterile peat carrier." Canadian Journal of Microbiology 42, no. 1 (January 1, 1996): 72–75. http://dx.doi.org/10.1139/m96-010.
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Sixty samples of commercial North American legume inoculants manufactured for sale in 1994 using nonsterile peat as carrier were tested for Rhizobium (or Bradyrhizobium) content and nonRhizobium biological contaminant load. Products of three major producers of such inoculants for sale in Canada were examined. Viable Rhizobium content varied from 5.6 × 105 to 8.1 × 109 cells/g, while the contaminant load varied from 1.8 × 108 to 5.5 × 1010 cfu/g. Most of the inoculants contained more nonrhizobial organisms than they did rhizobia. Identifications were made of the most numerous nonrhizobial bacteria occurring in 100 samples of inoculants collected in 1993 and 1994. The most commonly identified contaminant was Xanthomonas maltophilia. Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterobacter cloacae were also found at high levels in some products. Contaminant organisms capable of inhibiting rhizobial growth in plate culture were found in the products of all three manufacturers.Key words: Rhizobium, contaminant, inoculant.
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George, M. L. C., J. P. W. Young, and D. Borthakur. "Genetic characterization of Rhizobium sp. strain TAL1145 that nodulates tree legumes." Canadian Journal of Microbiology 40, no. 3 (March 1, 1994): 208–15. http://dx.doi.org/10.1139/m94-034.
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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.
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Chalifour, François-P., and Nicole Benhamou. "Indirect evidence for cellulase production by Rhizobium in pea root nodules during bacteroid differentiation: cytochemical aspects of cellulose breakdown in rhizobial droplets." Canadian Journal of Microbiology 35, no. 9 (September 1, 1989): 821–29. http://dx.doi.org/10.1139/m89-138.
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Cytochemical localization of cellulosic β-(1–4) glucans in pea (Pisum sativum L.) nodules at different stages of infection by an effective isolate of Rhizobium leguminosarum biovar viceae was studied using a gold-complexed exoglucanase. Cellulose subunits were present in great amounts in root cell walls, as shown by intense and regular labeling by gold particles. Labeling was unevenly distributed over the thin walls of emerging infection threads. In more developed infection threads, labeling was more intense and evenly distributed than in emerging threads, although slightly altered, unlabeled wall areas were frequently observed at the growing tips. Droplets containing rhizobia, which originated from infection threads, were surrounded by labeled wall-like material. Rhizobial droplets were either single- or multi-celled, and were sometimes separated by inner, unevenly labeled compartments. The surrounding wall-like material was irregularly labeled, and unlabeled wall areas, neighbouring intensely labeled ones, were observed frequently. There was an absence of labeling ahead of the rhizobia that escaped from the droplets, but degenerating wall-like material was present around the escaping rhizobia, mainly on their sides. At more advanced stages of development, labeling was present only over the outermost wall layers of rhizobial droplets, indicating that inner portions were degraded first. These observations suggest that a hydrolytic enzyme is involved in the sequence of events from infection thread formation through rhizobial release in the host cell cytoplasm, and that the hydrolytic enzyme is of rhizobial origin.Key words: Rhizobium–Pisum symbiosis, root nodules, rhizobial droplets, cellulose, colloidal gold.
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Sofi, Parvaze A., Iram Saba, and Zakir Amin. "Root architecture and rhizobial inoculation in relation to drought stress response in common bean (Phaseolus vulgaris l.)." Journal of Applied and Natural Science 9, no. 1 (March 1, 2017): 502–7. http://dx.doi.org/10.31018/jans.v9i1.1221.
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The present study was aimed at assessing the root traits and rhizobial inoculation in relation to drought in common bean, Phaseolus vulgaris. Drought caused the largest decrease in shoot biomass followed by plant height, while an increase was recorded inroot/shoot ratio. Rhizobial inoculation caused largest increase in shoot biomass followed by root volume and root biomass and smallest increase in rooting depth. WB-216 and WB-185 had better rooting depth in all treatments. However, WB-83 (92.67) had highest rooting depth under irrigated conditions and SR-1 had highest rooting depth under irrigated conditions treated with rhizobium (108.50). Similarly, WB-216 had highest root/shoot ratio under drought (2.693) followed by WB-185 (1.285) while lowest value was recorded for Arka Anoop (0.373). In rhizobium treated drought condition, WB-216 recorded highest root/shoot ratio (5.540) followed by SFB-1 (1.967). Under irrigated conditions (both with and without rhizobium), WB-185 recorded highest root/shoot ratio while lowest was recorded for SR-1 (0.166). The mean squares due to root depth, root biomass and root volume were significant whereas the mean squares due to water and rhizobium were non-significant. Among interactions the genotype x water regime was significant for rooting depth (5 % level), genotype x rhizobia was significant for rooting depth and root volume (1 % level) and the interaction of genotype x water regime x rhizobium was significant for rooting depth, root biomass and root volume (1 % level). The results reinforce the need to further analyse the potential of other soil microbes in common bean rhizosphere in amelioration of the effects of water stress.
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Fritz, V. A., and C. J. Rosen. "Productivity of processing peas as influenced by nitrogen fertilization, Rhizobium inoculation, and fungicide seed treatment." Canadian Journal of Plant Science 71, no. 4 (October 1, 1991): 1271–74. http://dx.doi.org/10.4141/cjps91-177.
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A 3-yr field experiment determined the influence of nitrogen (N) rates (0, 23, 46 and 92 kg ha−1), rhizobial inoculation, and fungicide (captan and thiram) seed treatment on the productivity of processing peas (Pisum sativum L.). In 2 of the 3 yr, N rates up to 46 or 92 kg N ha−1 increased vine fresh weight, decreased nodulation and had no effect on seed yield. Seeds treated with fungicides or inoculated with Rhizobium leguminosarum biovar viceae had no effect on vine fresh weight or seed yield. Nodule dry weight was increased in 2 of 3 yr when seeds were inoculated with Rhizobium. Key words: Pisum sativum, nodulation, rhizobia, fungicides
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Boiardi, J. L., and M. L. Galar. "Nodulation of Phaseolus vulgaris L. as affected by Rhizobium phaseoli growth phase." Canadian Journal of Microbiology 34, no. 1 (January 1, 1988): 63–67. http://dx.doi.org/10.1139/m88-011.
Full textAbstract:
The influence of culture age and of growth rate on the nodulation ability of strain F 45 str. Rhizobium phaseoli was studied. Roots of Phaseolus vulgaris L., grown in pouches, were infected with rhizobial suspensions (about 1 × 105 cells/root) taken from different batch cultures at different growth phases. After 24 h the free bacterial population was inhibited by adding tetracycline to the rooting medium. Nodules were counted 15–20 days after inoculation. More nodulation was obtained with rhizobia from early, mid, or late exponential phase than from lag or stationary phases. Differences in nodulation obtained had no correlation to the root attachment capacity of the cells nor to the rhizobial binding to Phaseolus vulgaris L. seed lectin. Bacterial attachment to bean roots was maximal with stationary phase bacteria, while lectin binding reached its maximal value with early exponential phase rhizobia, being very low with mid exponential phase cells. These results suggested that the difference in nodulation achieved with Rhizobium phaseoli at different growth phases could be caused by a step of the infection process not related to early (1 h) microbial attachment to roots nor to bacterial binding to Phaseolus vulgaris L. lectin.
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Habibi, Safiullah, Michiko Yasuda, Shafiqullah Aryan, Tadashi Yokoyama, Kalimullah Saighani, and Naoko Ohkama-Ohtsu. "Insights into Genetic and Physiological Characteristics of Clover Rhizobia in Afghanistan Soils." Applied Microbiology 4, no. 1 (January 8, 2024): 112–23. http://dx.doi.org/10.3390/applmicrobiol4010008.
Full textAbstract:
Livestock production in Afghanistan highly relies on grazing and clover feed, which is a key component of pastures and forage crops. This study elucidated the genetic diversity of clover-nodulating rhizobia in different ecological regions and their effects on clover growth. A total of 57 rhizobia were isolated and their genetic diversities were studied through 16S rRNA and nifD genes. The isolates were inoculated to clover (Afghan local variety), to investigate the potential of nitrogen fixation and influences of clover growth. The 16S rRNA gene analysis showed two distinct groups of Rhizobium (94.7%) and Ensifer (5.3%) species. The nifD phylogenetic relationship revealed a high similarity to Rhizobium and a novel lineage group close to Rhizobium leguminosarum species. In the plant test, different genotypes significantly (p < 0.01) exhibited an increase in plant biomass production, compared to the un-inoculated plants. Among genotypes, the highest plant biomass was recorded in PC8 (1769.0 mg/plant) and PC9 (1409.2 mg/plant) isolates as compared to un-inoculated plants (144.0 mg/plant). Moreover, these isolates showed maximum nitrogen fixation rates of 8.2 and 6.5 µM/plant, respectively. These isolates were identified as the most promising rhizobial strains for developing biofertilizers in the context of Afghanistan.
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Getachew, Zerihun, and Lejalem Abeble. "Effect of seed treatment using Mancozeb and Ridomil fungicides on Rhizobium strain performance, nodulation and yield of soybean (Glycine max L.)." Journal of Agriculture and Natural Resources 4, no. 2 (January 1, 2021): 86–97. http://dx.doi.org/10.3126/janr.v4i2.33674.
Full textAbstract:
The viability of commercial Rhizobium strains (SB-14 and SB-12) were inoculated and fungicides (Mancozeb and Ridomil) were used as seed dressed on soybean seed to investigate their effect on nodulation, plant growth and seed yield of soybean. Application of Rhizobial inoculants alone gave the highest nodulation and shoot dry weight performance as well as seed yield of soybean on both sites. SB-12 inoculant had significantly shown to be more effective than SB-14 inoculant in increasing nodulation and thus produced higher plant growth and seed yield. Rhizobial survival on the seeds was severely affected by both fungicides, resulting in decreased nodulation, plant growth and seed yield for both inoculants. However, Ridomil fungicide gave the lowest nodulation and seed yield when applied with either SB-12 or SB-14 Rhizobial strains. The strains differed in their sensitivity to Mancozeb fungicide that with strain SB-12 showed a slight effect or no effect on survival of rhizobium, nodulation and yield of soybean. Seed-dressing of mancozeb and ridomil resulted in reduction of seed yield by 882.8 kg ha-1 and 1154.7 kg ha-1, respectively with SB-12 strain. The present results indicate that inoculated Rhizobium inoculants differ in their capacity to develop resistance to the two dressed fungicides. Seed treatment with Mancozeb in combination with SB-12 strain slightly affected the survival of the inoculated strain. Consequently, mancozeb fungicide may be compatable with survival of the inoculated SB-12 Rhizobia. The results also indicate that the suppressive effects of seed-applied fungicides on Rhizobium strains survival and nodulation development depend on specific strain and fungicide. Soybean seeds inoculated with SB-12 may not need management with fungicides or lower concentration of Mancozeb that could be compatible with SB-12 to suppress soil-borne pathogens for both Assosa and Begi sites, western Ethiopia.
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Denton, M. D., D. R. Coventry, W. D. Bellotti, and J. G. Howieson. "Distribution, abundance and symbiotic effectiveness of Rhizobium leguminosarum bv. trifolii from alkaline pasture soils in South Australia." Australian Journal of Experimental Agriculture 40, no. 1 (2000): 25. http://dx.doi.org/10.1071/ea99035.
Full textAbstract:
The current dissatisfaction with low productivity of annual medic (Medicago spp.) pastures has highlighted the need to seek alternative legumes to provide efficient N2 fixation in low rainfall, alkaline soil environments of southern Australia. Clover species adapted to these environments will have limited N2 fixation if effective rhizobia are not present in sufficient quantities. A survey of 61 sites was conducted across South Australia to determine the size, distribution and effectiveness of Rhizobium leguminosarum bv. trifolii (clover rhizobia) populations resident in these low rainfall, alkaline soil environments. Clover rhizobia were detected at 56 of the sites, with a median density of 230–920 rhizobia/g soil. Most rhizobial populations were poor in their capacity to fix nitrogen. Rhizobial populations from fields provided 11–89% and 10–85% of the shoot biomass of commercial reference strains when inoculated onto host legumes T. purpureum (purple clover) and T. resupinatum (persian clover), respectively. Rhizobial population size was correlated negatively to pH and the percentage of CaCO3 in the soil, and was significantly increased in the rhizospheres of naturalised clover, found at 17 sites. Management options for rhizobial populations to improve legume diversity and productivity are discussed in terms of rhizobial population dynamics and likely soil constraints to successful rhizobial colonisation.
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Quides, Kenjiro W., and Hagop S. Atamian. "A microbiome engineering framework to evaluate rhizobial symbionts of legumes." Plant and Soil 463, no. 1-2 (March 4, 2021): 631–42. http://dx.doi.org/10.1007/s11104-021-04892-2.
Full textAbstract:
Abstract Background For well over a century, rhizobia have been recognized as effective biofertilizer options for legume crops. This has led to the widespread use of rhizobial inoculants in agricultural systems, but a recurring issue has emerged: applied rhizobia struggle to provide growth benefits to legume crops. This has largely been attributed to the presence of soil rhizobia and has been termed the ‘rhizobial competition problem.’ Scope Microbiome engineering has emerged as a methodology to circumvent the rhizobial competition problem by creating legume microbiomes that do not require exogenous rhizobia. However, we highlight an alternative implementation of microbiome engineering that focuses on untangling the complexities of the symbiosis that contribute to the rhizobial competition problem. We outline three approaches that use different starting inocula to test hypotheses to overcome the rhizobial competition problem. Conclusions The approaches we suggest are targeted at various stages of the legume-rhizobium symbiosis and will help us uncover underlying molecular mechanisms that contribute to the rhizobial competition problem. We conclude with an integrative perspective of these different approaches and suggest a path forward for future research on legumes and their complex microbiome.
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Chakrabarti, S. K., A. K. Mishra, and P. K. Chakrabartty. "DNA homology studies of rhizobia from Cicer arietinum L." Canadian Journal of Microbiology 32, no. 6 (June 1, 1986): 524–27. http://dx.doi.org/10.1139/m86-096.
Full textAbstract:
The taxonomic status of rhizobia which infect Cicer arietinum is poorly defined. Historically these organisms have been placed under Rhizobium leguminosarum; however, later reports suggested that they be treated as a separate cross-inoculation group. Therefore, DNA homology tests were carried out with various rhizobia. The data indicate that rhizobia from Cicer cannot be placed under any of the recognised species of Rhizobium.
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Slattery, J. F., D. R. Coventry, and W. J. Slattery. "Rhizobial ecology as affected by the soil environment." Australian Journal of Experimental Agriculture 41, no. 3 (2001): 289. http://dx.doi.org/10.1071/ea99159.
Full textAbstract:
In this paper we review the influence of various soil factors on the legume–Rhizobium symbiotic relationship. Abiotic factors such as extremes in soil pH (highly acidic or alkaline soils), salinity, tillage, high soil temperature and chemical residues, all of which can occur in crop and pasture systems in southern Australia, generally reduce populations of Rhizobium in the soil. Naturally occurring Rhizobium populations, although often found in high numbers, are generally poor in their ability to fix nitrogen and can compete strongly with introduced Rhizobium inoculant. The introduction of new legume genera as a continuing and essential part of change in farming systems usually requires the need to identify new and specific inoculant Rhizobium strains not found in the soil, but necessary for optimum nitrogen fixation. It is therefore necessary to characterise the specific requirements or limitations in the soil for establishing Rhizobium populations to ensure optimal nitrogen fixation following inoculation of legumes. The ability of the introduced Rhizobium to form effective nodules is rarely linked to a single soil attribute; therefore the study of rhizobial ecology requires an understanding of many soil and environmental factors. This paper reviews current knowledge of the influence of soil factors on rhizobial survival, the nodulation process, and nitrogen fixation by legumes.
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Chubukova, Olga V., Zilya R. Vershinina, Rustam T. Matnyazov, Andrey K. Baymiev, and Aleksey K. Baymiev. "Creation of an inducible vector system based on the rhizobia nodA gene promoter." Ecological genetics 19, no. 1 (March 15, 2021): 13–21. http://dx.doi.org/10.17816/ecogen48646.
Full textAbstract:
Background: The possibility of changing the properties of rhizobial bacteria by giving them the ability to regulate the expression of additionally introduced genes into them is an urgent task both for fundamental science and for applied agrobiology, since this will make it possible to obtain microsymbionts with desired properties. An expression construct using the rhizobia regulatory system was created in this work. The rhizobia nodD gene encodes a regulatory protein that, in the presence of plant inducers, flavonoids, activates the transcription of nod-genes involved in the early stages of the formation of legume-rhizobium symbiosis.
Materials and methods: A vector construct containing the nodD gene from Rhizobium leguminosarum bv. trifoli under the regulation of its own promoter and the gfp gene under the regulation of the nodA gene promoter from the same rhizobia was obtained. Neorhizobium galegae CIAM 0702 were transformed with the vector construct.
Results: It has been shown that in recombinant strains synthetic flavonoids are capable of inducing expression of gfp gene to varying degrees.
Conclusion: In the future, the results can be used to obtain rhizosphere microorganisms with a controlled synthesis of growth-stimulating and protective substances.
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Lancelle, Susan A., and John G. Torrey. "Early development of Rhizobium-induced root nodules of Parasponia rigida. II. Nodule morphogenesis and symbiotic development." Canadian Journal of Botany 63, no. 1 (January 1, 1985): 25–35. http://dx.doi.org/10.1139/b85-005.
Full textAbstract:
The Rhizobium-induced root nodules of Parasponia rigida (Ulmaceae) outwardly resemble those formed on actinorhizal plants, being coralloid in shape and consisting of multiple, branched lobes. The details of nodule morphogenesis also resemble more closely those which occur in an actinorhizal association than a typical Rhizobium–legume association and include prenodule formation, initiation of modified lateral roots which are termed nodule lobe primordia, and rhizobial colonization of tissues derived from the nodule lobe primordia to form the primary nodule lobes. Mature nodule lobe structure is actinorhizallike. Each lobe has an apical meristem and a central vascular cylinder which is surrounded by an uninfected inner cortex and then a zone of infected tissue. Peripheral to the infected tissue is an uninfected outer cortex. Infection threads and intercellular rhizobia progress continuously toward the apical meristem but do not infect the meristem itself. The establishment of the symbiosis in the host cells involves continuous thread formation after the initial infection until the host cells are nearly filled with rhizobia enclosed in threads. The rhizobia remain in threads throughout the symbiotic relationship and are not released from the threads as occurs in bacteroid formation in legumes.
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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.
Full textAbstract:
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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Lisboa, Bruno Britto, Thomas Müller Schmidt, Arthur Henrique Ely Thomé, Raul Antonio Sperotto, Camila Gazolla Volpiano, Jackson Freitas Brilhante de São Jose, Luciano Kayser Vargas, and Camille Eichelberger Granada. "Indigenous rhizobial strains SEMIA 4108 and SEMIA 4107 for common bean inoculation: A biotechnological tool for cleaner and more sustainable agriculture." Experimental Agriculture 57, no. 1 (February 2021): 57–67. http://dx.doi.org/10.1017/s0014479721000041.
Full textAbstract:
SummaryInoculation of symbiotic N2-fixing rhizobacteria (rhizobia) in legumes is an alternative to reduce synthetic N fertiliser input to crops. Even though common bean benefits from the biological N2 fixation carried out by native rhizobia isolates, the low efficiency of this process highlights the importance of screening new strains for plant inoculation. Two rhizobial strains (SEMIA 4108 and SEMIA 4107) previously showed great potential to improve the growth of common beans under greenhouse conditions. Thus, this study evaluated the growth and grain yield of common bean plants inoculated with those strains in field experiments. The rhizobial identification was performed by 16S rRNA sequencing and the phylogeny showed that SEMIA 4108 and SEMIA 4107 are closely related to Rhizobium phaseoli, within a clade containing other 18 Rhizobium spp. type strains. Common bean plants inoculated with SEMIA 4107 showed similar productivity to N-fertilised (N+) plants in the first experiment (2016/17) and higher productivity in the second experiment (2018/19). The development of inoculated plants was different from that observed for N+. Nonetheless, comparing inoculated treatments with N-fertilised control, no yield or productivity losses at the end of the growing process were detected. Our results showed that inoculation of the rhizobial isolates SEMIA 4108 and SEMIA 4107 improved the growth and grain yield of common bean plants. The observed agronomical performance confirms that both strains were effective and can sustain common bean growth without nitrogen fertilisation under the edaphoclimatic conditions of this study.
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NISTE, Monica, Roxana VIDICAN, Ioan ROTAR, and Rodica POP. "Characterization of the growth of Rhizobium trifolii and Sinorhizobium meliloti in different culture media." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 70, no. 1 (November 21, 2013): 80–86. http://dx.doi.org/10.15835/buasvmcn-agr:9559.
Full textAbstract:
Legumes have the ability to form symbiotic interactions with soil bacteria, called rhizobia. Bacteria of the genus Rhizobium are able to convert atmospheric nitrogen into ammonia when compounds are exchanged between the bacteroid and its plant host. The present study describes the characterization of Rhizobium strains isolated from root nodules of Trifolium pratense and Medicago sativa grown in a greenhouse. The main objective of the experiment was to identify which medium is more suitable for the development of different strains of rhizobia. The Rhizobium strains are rod shaped, Gram negative and mucus producing. The rhizobia were identified and isolated using different media yeast extract mannitol agar (YEMA) containing Congo red, and a medium including boron (B), an essential micronutrient. The Petri plates were incubated at 28ºC and inspected three days after the inoculation. The colony morphology was analysed based on type, appearance, transparency, colour and the effectiveness of boron on Rhizobium growth.
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Crook, Matthew B., Daniel P. Lindsay, Matthew B. Biggs, Joshua S. Bentley, Jared C. Price, Spencer C. Clement, Mark J. Clement, Sharon R. Long, and Joel S. Griffitts. "Rhizobial Plasmids That Cause Impaired Symbiotic Nitrogen Fixation and Enhanced Host Invasion." Molecular Plant-Microbe Interactions® 25, no. 8 (August 2012): 1026–33. http://dx.doi.org/10.1094/mpmi-02-12-0052-r.
Full textAbstract:
The genetic rules that dictate legume-rhizobium compatibility have been investigated for decades, but the causes of incompatibility occurring at late stages of the nodulation process are not well understood. An evaluation of naturally diverse legume (genus Medicago) and rhizobium (genus Sinorhizobium) isolates has revealed numerous instances in which Sinorhizobium strains induce and occupy nodules that are only minimally beneficial to certain Medicago hosts. Using these ineffective strain-host pairs, we identified gain-of-compatibility (GOC) rhizobial variants. We show that GOC variants arise by loss of specific large accessory plasmids, which we call HR plasmids due to their effect on symbiotic host range. Transfer of HR plasmids to a symbiotically effective rhizobium strain can convert it to incompatibility, indicating that HR plasmids can act autonomously in diverse strain backgrounds. We provide evidence that HR plasmids may encode machinery for their horizontal transfer. On hosts in which HR plasmids impair N fixation, the plasmids also enhance competitiveness for nodule occupancy, showing that naturally occurring, transferrable accessory genes can convert beneficial rhizobia to a more exploitative lifestyle. This observation raises important questions about agricultural management, the ecological stability of mutualisms, and the genetic factors that distinguish beneficial symbionts from parasites.
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Ma, Wenbo, Frèdèrique C. Guinel, and Bernard R. Glick. "Rhizobium leguminosarum Biovar viciae 1-Aminocyclopropane-1-Carboxylate Deaminase Promotes Nodulation of Pea Plants." Applied and Environmental Microbiology 69, no. 8 (August 2003): 4396–402. http://dx.doi.org/10.1128/aem.69.8.4396-4402.2003.
Full textAbstract:
ABSTRACT Ethylene inhibits nodulation in various legumes. In order to investigate strategies employed by Rhizobium to regulate nodulation, the 1-aminocyclopropane-1-carboxylate (ACC) deaminase gene was isolated and characterized from one of the ACC deaminase-producing rhizobia, Rhizobium leguminosarum bv. viciae 128C53K. ACC deaminase degrades ACC, the immediate precursor of ethylene in higher plants. Through the action of this enzyme, ACC deaminase-containing bacteria can reduce ethylene biosynthesis in plants. Insertion mutants with mutations in the rhizobial ACC deaminase gene (acdS) and its regulatory gene, a leucine-responsive regulatory protein-like gene (lrpL), were constructed and tested to determine their abilities to nodulate Pisum sativum L. cv. Sparkle (pea). Both mutants, neither of which synthesized ACC deaminase, showed decreased nodulation efficiency compared to that of the parental strain. Our results suggest that ACC deaminase in R. leguminosarum bv. viciae 128C53K enhances the nodulation of P. sativum L. cv. Sparkle, likely by modulating ethylene levels in the plant roots during the early stages of nodule development. ACC deaminase might be the second described strategy utilized by Rhizobium to promote nodulation by adjusting ethylene levels in legumes.
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Ding, Hao, and Michael F. Hynes. "Plasmid transfer systems in the rhizobia." Canadian Journal of Microbiology 55, no. 8 (August 2009): 917–27. http://dx.doi.org/10.1139/w09-056.
Full textAbstract:
Rhizobia are agriculturally important bacteria that can form nitrogen-fixing nodules on the roots of leguminous plants. Agricultural application of rhizobial inoculants can play an important role in increasing leguminous crop yields. In temperate rhizobia, genes involved in nodulation and nitrogen fixation are usually located on one or more large plasmids (pSyms) or on symbiotic islands. In addition, other large plasmids of rhizobia carry genes that are beneficial for survival and competition of rhizobia in the rhizosphere. Conjugative transfer of these large plasmids thus plays an important role in the evolution of rhizobia. Therefore, understanding the mechanism of conjugative transfer of large rhizobial plasmids provides foundations for maintaining, monitoring, and predicting the behaviour of these plasmids during field release events. In this minireview, we summarize two types of known rhizobial conjugative plasmids, including quorum sensing regulated plasmids and RctA-repressed plasmids. We provide evidence for the existence of a third type of conjugative plasmid, including pRleVF39c in Rhizobium leguminosarum bv. viciae strain VF39SM, and we provide a comparison of the different types of conjugation genes found in members of the rhizobia that have had their genomes sequenced so far.
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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.
Full textAbstract:
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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Rahman, M., ME Ali, F. Alam, MB Banu, MI Faruk, and MAH Bhuiyan. "Biocontrol of Foot and Root Rot Disease of Grasspea (Lathyrus sativus) by Dual Inoculation with Rhizobium and Arbuscular Mycorrhiza." Bangladesh Journal of Microbiology 34, no. 2 (January 1, 2019): 109–17. http://dx.doi.org/10.3329/bjm.v34i2.39622.
Full textAbstract:
The present study was carried out to evaluate the effect of indigenous arbuscular mycorrhizal fungi (AMF) and Rhizobium (R) on plant growth and their biocontrol against grasspea foot and root rot disease caused by Sclerotium rolfsii. The bio-control potential of these bio-agents against foot and root rot pathogen was carried out under pot culture condition using AMF alone or in combination with rhizobial inoculum in the nethouse of Soil Science Division, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur during 2014-2015 through 2015-2016. The experiment was designed in RCBD with 8 treatments and 4 replications. Grasspea variety BARI Khesari-1 was used as a test crop. Peat based rhizobial inoculum (BARI RLs-10) was used in this experiment @ 50 g kg-1 seed. The AM fungi used in this experiment were Glomus fusianum, Glomus macrocarpum, Glomus warcuppi, Acaulospora foveata, Acaulospora denticulate, Gigaspora albida, Gigaspora rosea, Glomus spp. etc. Soil based AM inoculum containing about approximate 252 spores and infected root pieces of the host plant was used pot-1. There were eight treatments viz. T1: Arbuscular mycorrhiza (AM), T2: Rhizobium, T3: AM + Rhizobium, T4: Sclerotium rolfsii, T5: Sclerotium rolfsii + AM, T6: Sclerotium rolfsii + Rhizobium, T7: Sclerotium rolfsii + AM + Rhizobium and T8: Control. Dual inoculation (AM + Rhizobium) increased 20-25% germination, 50-100% seed yield and 36-98% stover yield compared to control. Dual inoculation reduced 44-48% foot and root rot disease compared to control. On the contrary, Sclerotium rolfsii + Rhizobium, Sclerotium rolfsii + AM, and Sclerotium rolfsii + AM + Rhizobium reduced 12-17%, 16-20% and 28-31% foot and root rot disease, respectively compared to only Sclerotium rolfsii trearment. Therefore, arbuscular mycorrhizal fungal species and its combination with rhizobial inoculum were significant both in the formation and effectiveness of AM symbiosis and the reduction of foot and root rot incidence in grasspea plants. Use of these bio-control agents could be promoted as an active component of bio-intensive Integrated Disease Management Program (IDMP) under organic mode.
Bangladesh J Microbiol, Volume 34 Number 2 December 2017, pp 109-117
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Sharma, Naveen, Shivesh Sharma, Vivek Kumar, Punam, and Atul. "Species specific Rhizobium - albizia Lebbeck interaction." Indian Journal of Forestry 29, no. 2 (June 1, 2006): 175–79. http://dx.doi.org/10.54207/bsmps1000-2006-f8ehoo.
Full textAbstract:
The Rhizobium strain isolated from A. lebbeck nodules performed significantly as compared to other rhizobial strains isolated from Delbergia sissoo and Acacia catechu. There was increase in growth parameters viz., plant height (41%), collar diameter (12%), nodule formation (200%) and biomass yield (199%), with rhizobial strain (R3) in comparison with control. The maximum IAA, NH3 excretion and nitrogenase activity was noticed in Rhizobium strains isolated from A. lebbeck and D. sissoo and the lowest was recorded in A. catechu isolate.
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Stambulska, Uliana Ya, Maria M. Bayliak, and Volodymyr I. Lushchak. "Chromium(VI) Toxicity in Legume Plants: Modulation Effects of Rhizobial Symbiosis." BioMed Research International 2018 (February 14, 2018): 1–13. http://dx.doi.org/10.1155/2018/8031213.
Full textAbstract:
Most legume species have the ability to establish a symbiotic relationship with soil nitrogen-fixing rhizobacteria that promote plant growth and productivity. There is an increasing evidence of reactive oxygen species (ROS) important role in formation of legume-rhizobium symbiosis and nodule functioning. Environmental pollutants such as chromium compounds can cause damage to rhizobia, legumes, and their symbiosis. In plants, toxic effects of chromium(VI) compounds are associated with the increased production of ROS and oxidative stress development as well as with inhibition of pigment synthesis and modification of virtually all cellular components. These metabolic changes result in inhibition of seed germination and seedling development as well as reduction of plant biomass and crop yield. However, if plants establish symbiosis with rhizobia, heavy metals are accumulated preferentially in nodules decreasing the toxicity of metals to the host plant. This review summarizes data on toxic effects of chromium on legume plants and legume-rhizobium symbiosis. In addition, we discussed the role of oxidative stress in both chromium toxicity and formation of rhizobial symbiosis and use of nodule bacteria for minimizing toxic effects of chromium on plants.
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Zarina, Livija, Ina Alsina, and Aija Vaivode. "EFFECTIVENESS OF RHIZOBIAL STRAINS ON THE FABA BEAN DEVELOPMENT AND YIELD IN SODDY PODZOLIC SOILS." Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 1 (June 15, 2017): 305. http://dx.doi.org/10.17770/etr2017vol1.2556.
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In the frame of EU 7th Research Framework Programme of The European Union project EUROLEGUME (Enhancing of legumes growing in Europe through sustainable cropping for protein supplay for food and feed) two Rhizobium leguminosarium strains alone and in mixture were examinated to evaluate the influence on yield formation of faba bean (Vicia faba L.) ‘Lielplatones’. The field experiment was carried out at the Institute of Agricultural Resources and Economics between 2014 -2016 in the organic cropping system field. The beans seeds were treated with rhizobia fungi by soaking in bacteria suspension for 30 minutes before sowing. A plant high was measured at the beginning of flowering (BBCH 61- 64), at the beginning of forming pods (BBCH 71- 75) and at the beginning of maturity (BBCH 81- 85).
The inoculation of plant seeds promotes a slight increase in the plant length. The highest yield was from seeds inoculated with strain R2. There were no significant differences between tested strains. The results of this investigation indicate that rhizobium inoculation is a recommendable management tool for faba beans generally but effectiveness of rhizobial strains strongly depending climate conditions. Seed treatment with Rhizobium contributed to an increase in the quantity of nitrogen in the soil.
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Hafeez, F. Y., M. E. Safdar, A. U. Chaudhry, and K. A. Malik. "Rhizobial inoculation improves seedling emergence, nutrient uptake and growth of cotton." Australian Journal of Experimental Agriculture 44, no. 6 (2004): 617. http://dx.doi.org/10.1071/ea03074.
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Experiments were conducted to determine the growth promoting activities of various rhizobia in cotton (Gossypium hirsutum L.) under growth room conditions. Seeds of 4 cotton cultivars were inoculated with 4-indole-3-acetic acid producing selected (Brady) rhizobium strains and Azotobacter plant growth promoting rhizobacteria strains, included as a positive control. Growth responses to inoculation exhibited bacterial strain-cotton cultivar specificity and also included increase in rate of seedling emergence by 3–9%. Shoot dry weight, biomass and N uptake were increased by 48, 75 and 57%, respectively, due to inoculation with both the Rhizobium leguminosarum bv. trifolii E11 and Azotobacter sp. S8, whereas, strain E11 also increased root dry weight, root length and area by 248, 332 and 283%, respectively. K+ and Ca2+ uptake was also increased by 2–21% and 9–14%, respectively, due to rhizobial inoculation. The results also showed that (Brady) rhizobium strains promoted cotton growth through efficient nutrient uptake, which was mainly related to increased root growth due to the effect of IAA produced by these strains. However, growth promotion by Azotobacter sp. S8, in addition to 4-indole-3-acetic acid production, might also involve biological N2 fixation by this rhizobacterial strain at some stage during its growth.
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Bernal, G. R., B. Tlusty, C. Estevez de Jensen, P. van Berkum, and P. H. Graham. "Characteristics of rhizobia nodulating beans in the central region of Minnesota." Canadian Journal of Microbiology 50, no. 12 (December 1, 2004): 1023–31. http://dx.doi.org/10.1139/w04-092.
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Until recently, beans (Phaseolus vulgaris L.) grown in Minnesota were rarely inoculated. Because of this, we hypothesized that bean rhizobia collected in Minnesota would either share characteristics identifiable with Rhizobium etli of Mesoamerican or Andean origin, introduced into the region as seed-borne contaminants, or be indigenous rhizobia from prairie species, such as Dalea spp. The latter organisms have been shown to nodulate and fix N2with Phaseolus vulgaris. Rhizobia recovered from the Staples, Verndale, and Park Rapids areas of Minnesota were grouped according to the results of BOXA1R–PCR fingerprint analysis into 5 groups, with only one of these having banding patterns similar to 2 of 4 R. etli reference strains. When representative isolates were subject to fatty acid - methyl ester analysis and 16S rRNA gene sequence analysis, the results obtained differed. 16S rRNA gene sequences of half the organisms tested were most similar to Rhizobium leguminosarum. Rhizobia from Dalea spp., an important legume in the prairie ecosystem, did not play a significant role as the microsymbiont of beans in this area. This appears to be due to the longer time needed for them to initiate infection in Phaseolus vulgaris. Strains of Rhizobium tropici IIB, including UMR1899, proved tolerant to streptomycin and captan, which are commonly applied as seed treatments for beans. Local rhizobia appeared to have very limited tolerance to these compounds.Key words: Rhizobium diversity, Phaseolus vulgaris, seed treatment, taxonomy.
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Hu, Yiao, Yulin Chen, Xu Yang, Lansheng Deng, and Xing Lu. "Enhancing Soybean Yield: The Synergy of Sulfur and Rhizobia Inoculation." Plants 12, no. 22 (November 20, 2023): 3911. http://dx.doi.org/10.3390/plants12223911.
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Sulfur deficiency severely limits soybean growth, inhibiting the rhizobia nitrogenase and soybean protein synthesis. This study assessed the impact of sulfur fertilization and rhizobia inoculation on soybean growth and nitrogen fixation through bacterial culture and hydroponic experiments. We selected three rhizobia strains for bacterial cultures and used six sulfur levels. The test demonstrated severe inhibition of Rhizobium USDA110 growth without sulfur. In hydroponic experiment, we employed five sulfur levels with USDA110 as the inoculum strain. Soybean growth, nitrogen fixation, yield, and root morphology-related parameters, and root nodule growth, were significantly inhibited without sulfur. Following Rhizobium inoculation, low sulfur concentrations (0.15–0.60 mM) stimulated early-stage (V9) root growth and increased shoot nitrogen accumulation, but inhibited root growth at R5 stage. Furthermore, Rhizobium inoculation notably enhanced soybean growth, nitrogen fixation, and yield, especially within the recommended low sulfur concentration range (0.15–0.30 mM). The maximum nodule nitrogenase activity at R5 stage and highest yield was recorded at a 0.3 mM sulfur concentration with Rhizobium inoculation, which was 9.51–1222.07% higher than other treatments. These findings highlight that low sulfur concentration and rhizobia inoculation enhance soybean growth, nitrogen fixation, and yield but reduce soybean root efficacy, increasing reliance on root nodules.
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Tlusty, B., P. van Berkum, and P. H. Graham. "Characteristics of the rhizobia associated with Dalea spp. in the Ordway, Kellogg–Weaver Dunes, and Hayden prairies." Canadian Journal of Microbiology 51, no. 1 (January 1, 2005): 15–23. http://dx.doi.org/10.1139/w04-107.
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Habitat fragmentation affects the biodiversity and function of aboveground organisms in natural ecosystems but has not been studied for effects on belowground species. In this paper, we consider the diversity of the rhizobia associated with the indigenous legume Dalea purpurea in 3 residual prairie areas in Minnesota and Iowa. Using Dalea purpurea as a trap host, 218 rhizobia were recovered from these soils then characterized using BOXA1R PCR. Three major and 13 minor groups were distinguished based on a similarity of greater than 75% in fingerprint patterns. Each major group consisted almost exclusively of rhizobia from a single prairie, with the diversity of Dalea rhizobia recovered from the Hayden Prairie less than that obtained with rhizobia from the other prairies. Based on 16S rRNA gene sequence analysis, isolates from the Hayden, Ordway, and Kellogg–Weaver Dunes prairies were most similar to Rhizobium etli and Rhizobium leguminosarum, Rhizobium gallicum, and Mesorhizobium amorphae and Mesorhizobium huakuii, respectively. This variation in the dominant microsymbiont species across the 3 prairies studied was unexpected but could have been influenced by the limited number of samples that we were allowed to take, by unanticipated cross-nodulation between native legumes, and by variation in the range of legume species present in each residual prairie area. While some of the rhizobia from Dalea nodulated Phaseolus vulgaris, Macroptilium atropurpureum, Leucaena leucocephala, and Onobrychis viciifolia in addition to the Dalea species tested, others nodulated Astragalus canadensis or Amorpha canescens.Key words: Rhizobium, Dalea, prairie, diversity, fragmentation, rep PCR.
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Perrine, Francine M., Joko Prayitno, Jeremy J. Weinman, Frank B. Dazzo, and Barry G. Rolfe. "Rhizobium plasmids are involved in the inhibition or stimulation of rice growth and development." Functional Plant Biology 28, no. 9 (2001): 923. http://dx.doi.org/10.1071/pp01046.
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This paper originates from an address at the 8th International Symposium on Nitrogen Fixation with Non-Legumes, Sydney, NSW, December 2000 We examined growth responses of rice seedlings (Oryza sativaL. cv. Pelde) to specific Rhizobium strains and their mutants, to investigate the molecular basis of colonization and the stimulation or inhibition of rice growth and development by rhizobia. Inoculation experiments with rice seedlings showed that specific Rhizobium isolates of these rice-associated and legume-associated rhizobia could either promote, inhibit, or have no influence on rice plant growth. There are genes on certain plasmids of Rhizobium leguminosarum bv. trifolii and R. leguminosarum bv. viciae that affect the growth and development of rice root morphology. Additionally, we found that bacteria can intimately associate with, and enter into, rice seedling roots by alternative mechanisms to those encoded by the symbiotic (pSym) and the tumour-inducing (Ti) plasmids. Investigations suggest an involvement of the phytohormone auxin, and possibly nitrate, in this complex rice–Rhizobium interaction.
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Rincón-Rosales, Reiner, José M. Villalobos-Escobedo, Marco A. Rogel, Julio Martinez, Ernesto Ormeño-Orrillo, and Esperanza Martínez-Romero. "Rhizobium calliandrae sp. nov., Rhizobium mayense sp. nov. and Rhizobium jaguaris sp. nov., rhizobial species nodulating the medicinal legume Calliandra grandiflora." International Journal of Systematic and Evolutionary Microbiology 63, Pt_9 (September 1, 2013): 3423–29. http://dx.doi.org/10.1099/ijs.0.048249-0.
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Calliandra grandiflora has been used as a medicinal plant for thousands of years in Mexico. Rhizobial strains were obtained from root nodules of C. grandiflora collected from different geographical regions in Chiapas and characterized by BOX-PCR, amplified rDNA restriction analysis (ARDRA) and 16S rRNA gene sequence analysis. Most isolates corresponded to members of the genus Rhizobium and those not related to species with validly published names were further characterized by recA, atpD, rpoB and nifH gene phylogenies, phenotypic and DNA–DNA hybridization analyses. Three novel related species of the genus Rhizobium within the ‘ Rhizobium tropici group’ share the same symbiovar that may be named sv. calliandrae. The names proposed for the three novel species are Rhizobium calliandrae sp. nov. (type strain, CCGE524T = ATCC BAA-2435T = CIP 110456T = LBP2-1T), Rhizobium mayense sp. nov. (type strain, CCGE526T = ATCC BAA-2446T = CIP 110454T = NSJP1-1T) and Rhizobium jaguaris sp. nov. (type strain, CCGE525T = ATCC BAA-2445T = CIP 110453T = SJP1-2T).
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Nguyen, Nguyen Thi Hanh, Vo Thi Minh Thao, Nguyen Minh Khanh, Pham Cam Duyen, Phung Thi Tram, Doan Thi Minh Thu, Le Thi Phuong Thao, et al. "Isolation and characterization of Rhizobium spp. and Bradyrhizobium spp. from legume nodules." HO CHI MINH CITY OPEN UNIVERSITY JOURNAL OF SCIENCE - ENGINEERING AND TECHNOLOGY 12, no. 2 (November 4, 2022): 70–98. http://dx.doi.org/10.46223/hcmcoujs.tech.en.12.2.2116.2022.
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Rhizobia topic has been re-focused in recent years because of new findings on their traits not only as nitrogen-fixing bacteria but also as plant growth-promoting rhizobacteria. When combing rhizobial strains with novel biological carriers (e.g., biochar) for inoculant production, it brings great potential for improving soil health in long-term. Appreciating this trend, this study is designed to isolate and characterize local rhizobial strains from legume fields using the conventional method with some modifications to increase efficiency in rhizobial identification. As a result, 17 rhizobial strains were isolated and classified biochemically that genetic identification outcome confirmed 10 strains belong to 07 different Rhizobium species as R. mayense, R. paknamense, R. pusense, R. miluonense, R. tropici, R. phaseoli, and R. multihospitium while the rest belong to 06 various Bradyrhizobium species as B. elkanii, B. centrosematis, B. guangxiense, B. liaoningense, B. yuanmingense, and B. arachidis. Thermal and saline tolerant tests together with seed germination tests also performed on these rhizobial strains to gain data on their responses to abiotic stresses. By comparing rice and mung bean GI values, we can assess the effectiveness of each rhizobial strains to help seeds at their early germination.
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Andrews, M., D. Jack, D. Dash, and S. Brown. "Which rhizobia nodulate which legumes in New Zealand soils?" Journal of New Zealand Grasslands 77 (January 1, 2015): 281–86. http://dx.doi.org/10.33584/jnzg.2015.77.465.
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Recent work which genotypically characterised rhizobia of native, crop and weed legumes in New Zealand and examined their cross-nodulation ability is reviewed and related to earlier work with focus on New Zealand pasture systems. The New Zealand native legumes were exclusively effectively nodulated by novel strains of Mesorhizobium which did not nodulate crop or weed legumes. Clovers, lucerne, Lotus and grain legumes were effectively nodulated by different genera, species and biovars of rhizobia primarily originating from inoculum. Rhizobial symbionts of white clover have established over wide areas in New Zealand. Weed legumes are effectively nodulated by different genera/ species of rhizobia depending on species. Bradyrhizobia that cross-nodulate lupins, gorse, European broom and tagasaste are widespread in New Zealand. Keywords: Bradyrhizobium, Burkholderia, Ensifer, Mesorhizobium, Rhizobium
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Athar, Mohammad, and Douglas A. Johnson. "The influence of soil water potential on the growth and survival of alfalfa rhizobia in the soil." Acta Societatis Botanicorum Poloniae 66, no. 1 (2014): 55–59. http://dx.doi.org/10.5586/asbp.1997.008.
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Growth and survival of alfalfa rhizobia (<em>Rhizobium meliloti</em> Dang.) from Pakistan and Nepal were studied in vials filled with sterile soil maintained at -0.03, -1.0, and -1.5 MPa. The main effects of water level, rhizobial strains and length of exposure to desiccation and their interactions showed a highly significant (P S 0.001) effect on the number of rhizobia g<sup>-1</sup> of soil. Growth and survival of rhizobia were highest in soil at -0.03 MPa followed by soil at -1.0 and -1.5 MPa. Highest cell counts were observed for strain UL 136 followed by strain UL 222 and the lowest was for strain UL 61. Two rhizobial strains (UL 136 and UL 222) were most tolerant to desiccation and showed highest growth and survival under low water potential. These two strains probably could be used as inoculants for alfalfa production under arid and semiarid environments.
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Rahman, Mominur, Faridul Alam, Md Nazrul Islam, Md Farid Ahammed Anik, and Mohammad Eyakub Ali. "Biocontrol of Foot and Root Rot Disease of Groundnut (Arachis hypogaea) by Dual Inoculation with Rhizobium and Arbuscular Mycorrhiza." American Journal of Agricultural Science, Engineering, and Technology 7, no. 1 (March 12, 2023): 67–76. http://dx.doi.org/10.54536/ajaset.v7i1.1296.
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The present study was carried out to investigate the potential of AM (Arbuscular mycorrhiza) fungi alone and in combination with bioinoculants i.e., Rhizobium to find out the best combination on dry biomass, nodulation, colonization, and yield, along with their biocontrol against groundnut foot and root rot caused by Sclerotium rolfsii. The study was carried out under pot culture conditions in the net house of the Soil Science Division, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur in 2020 and 2021. The experiment was designed in RCBD with eight treatments and four replications. Peat-based rhizobial inoculum (BARI RAh-801) was used @ 1.5 kg ha-1 in this experiment. Soil-based AM inoculum containing approximately 252 spores and infected root pieces of the host plant was used in pot-1. The treatments were Arbuscular mycorrhiza (AM), Rhizobium, AM+Rhizobium, Sclerotium rolfsii, Sclerotium rolfsii+AM, Sclerotium rolfsii+Rhizobium, Sclerotium rolfsii+AM+Rhizobium and Control. Dual inoculation (AM+Rhizobium) significantly increased dry biomass, nodulation, colonization, yield, and yield attributes of groundnut compared to single inoculation or other treatments. The result showed that dual inoculation (AMF+Rhizobium) increased nut yield (59.61% in 2020 and 26.32% in 2021) and stover yield (23.21% in 2020 and 33.74% in 2021) compared to control. On the contrary, Sclerotium rolfsii+AMF+Rhizobium increased nut yield (65.50% in 2020 and 52.94% in 2021) and stover yield (36.45% in 2020 and 99.35% in 2021) compared to only Sclerotium rolfsii treatment. The plant dry biomass, nodulation, colonization, nutrient concentration and uptake were increased by dual inoculation under pathogenic and non-pathogenic conditions leading to an improved yield of groundnut. Therefore, AMF species and its combination with rhizobial inoculum were significant in the formation and effectiveness of AM fungi symbiosis. They also increased yield and reduced the incidence of foot and root rot disease in groundnut plants.