Characterization of hup-specific DNA in Rhizobium leguminosarum strains of different origin

Nelson, L

doi:10.1016/0378-1097(85)90364-7

Cited by 8 publications

(10 citation statements)

References 9 publications

(12 reference statements)

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“…However, some of the gene products (e.g., HypB protein) involved with hydrogenase in the symbiotic bacteria have been well characterized compared with the other systems, and some hydrogenase-related genes have been found thus far only in B. japonicum (e.g., hupNOP operon). hup DNA resides on the large plasmid known as pSym in both R. leguminosarum strains from which hup genes have been isolated, (Leyva et al, 1987a;Nelson et al, 1985), and for at least one common bean rhizobium (Navarro et al, 1993). The B. japonicum hup genes presumably reside on the chromosome because Hup+ B. japonicum strains lack detectable plasmids (Cantrell et al, 1982).…”

Section: A Hydrogenase Genes In Symbiotic Bacteriamentioning

confidence: 98%

Toward More Productive, Efficient, and Competitive Nitrogen-Fixing Symbiotic Bacteria

Maier

Triplett

1996

Critical Reviews in Plant Sciences

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The prospects of developing strains of legume nodule bacteria that provide higher productivity of leguminous plants are described. The generic, biochemical, physiological, regulatory, and economic constraints that govern the ability of private and public efforts to construct better inoculants for legume nodulation are discussed. Success in constructing better inoculants requires a two-pronged approach. First, strains need to be improved in order to compete successfully with indigenous strains for root nodulation of legumes. Several loci have been identified to date that affect competitiveness for strain nodule occupancy. Usually mutations in these loci affect the ability of a strain to form nodules rapidly and efficiently. Other loci, such as those that confer antibiotic production, can be added to strains to enhance nodulation competitiveness when co-inoculated with antibiotic-sensitive strains. Second, the inoculum strains must be improved with respect to symbiotic nitrogen fixation. Efforts to enhance the symbiotic productivity of legume nodule bacteria either by mutation or genetic engineering are also described. The best characterized example of these is the hydrogenase system. Due to nitrogenase-dependent catalysis of proton reduction, diazotrophs evolve large amounts of H,. An approach to maximize the efficiency of symbiotic N, fixation, and therefore of legume productivity, is to construct strains of Rhizobium with the ability to oxidize this otherwise wasted H,. The electrons produced by H, oxidation are funneled through energy-conserving electron transport chains. Our knowledge of the genetics and biochemistry of H, oxidation in Bradyrhizobium japonicum and Rhizobium leguminosarum has developed rapidly in recent years. At least 20 genes are needed for these bacteria to manufacture and efficiently express a nickel-containing H,-uptake hydrogenase. These genes include those encoding regulatory elements, posttranslational processing enzymes, nickel-sensing and nickel-metabolism proteins, and electron transport components for integrating the electrons from H, oxidation into the respiratory chain. Some of the components for oxidizing H, in the symbiotic N, fixing bacteria are distinct from the analogous components in (nonsymbiotic) H, oxidizing bacteria.

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Section: A Hydrogenase Genes In Symbiotic Bacteriamentioning

confidence: 98%

Toward More Productive, Efficient, and Competitive Nitrogen-Fixing Symbiotic Bacteria

Maier

Triplett

1996

Critical Reviews in Plant Sciences

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“…We expected that hup DNA sequences were conserved within endosymbiotic bacteria, since hup DNA from B. japonicum has been shown to be homologous to hup DNA from R. leguminosarum (18,22) and Azotobacter chroococcum (28 …”

Section: Conservation Of Presumptive Hup Sequencesmentioning

confidence: 99%

“…The recycling of H2 by these Hup+ strains is claimed to increase N2 fixation and crop productivity in soybeans (9,10 Genes involved in the H2 uptake process (hup genes) were first cloned and isolated in B. japonicum strain 122DES (6). The existence of homology between hup specific DNA from R. japonicum 122DES and DNA from Hup+ strains of R. leguminosarum biovar viceae has been demonstrated (18,22) and used to isolate hup genes from this rhizobial species (17 (2-5 cm). Ethylene (C2H4) and H2 were quantified by gas chromatography using flame ionization and thermal conductivity detectors, respectively, with columns and conditions previously described (19).…”

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confidence: 99%

Occurrence of H₂-Uptake Hydrogenases in Bradyrhizobium sp. (Lupinus) and Their Expression in Nodules of Lupinus spp. and Ornithopus compressus

Murillo¹,

Villa²,

Chamber³

et al. 1989

Plant Physiol.

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Fifty-four strains of Bradyrhizobium sp. (Lupinus) from worldwide collections were screened by a colony hybridization method for the presence of DNA sequences homologous to the structural genes of the Bradyrhizobium japonicum hydrogenase. Twelve strains exhibited strong colony hybridization signals, and subsequent Southem blot hybridization experiments showed that they fell into two different groups on the basis of the pattem of EcoRI fragments containing the homology to the hup probe. All strains in the first group (UPM860, UPM861, and 750) expressed uptake hydrogenase activity in symbiosis with Lupinus albus, Lupinus angustifoiius, Lupinus luteus, and Ornithopus compressus, but both the rate of H2 uptake by bacteroids and the relative efficiency of N2 fixation (RE = 1 -[H2 evolved in air/acetylene reduced)) by nodules were markedly affected by the legume host. L. angustifolius was the less permissive host for hydrogenase expression in symbiosis with the three strains (average RE = 0.76), and 0. compressus was the more permissive (average RE = 1.0). None of the strains in the second group expressed hydrogenase activity in lupine nodules, and only one exhibited low H2-uptake activity in symbiosis with 0. compressus. The inability of these putative Hup+ strains to induce hydrogenase activity in lupine nodules is discussed on the basis of the legume host effect. Among the 42 strains showing no homology to the B. japonicum hup-specific probe in the colony hybridization assay, 10 were examined in symbiosis with L. angustffolius. The Lupines are nodulated by slow-growing rhizobia that also infect Ornithopus sp. These rhizobia have been included in the genus Bradyrhizobium and designated as Bradyrhizobium sp. (Lupinus) (14). To extend the cultivation of lupines to new areas, there is a need for inoculation of seeds with appropriate rhizobial strains (1, 24). The possession of H2 uptake hydrogenase has been considered as a desirable characteristic of rhizobial strains to be used as legume inoculants. This assessment is based mainly on experiments with strains of Bradyrhizobium japonicum containing H2 uptake hydrogenase (Hup+ strains), which recycle the H2 generated by nitrogenase as an obligate by-product of the N2 fixation process. The recycling of H2 by these Hup+ strains is claimed to increase N2 fixation and crop productivity in soybeans (9,10

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“…Although these results certainly do not suggest that Hup activity in all types of rhizobia would be increased in the presence of NaCl, the strains selected for these tests represent a diverse sample from R. leguminosarum. Nelson et al (20), for example, used hup-specific DNA hybridization probes from various sources to demonstrate different hybridization characteristics in strains 128C 13, 128C30, 128C53, and 175R1. The Hup system in R. meliloti strain B300 is determined by the same plasmid, pRL6JI, present in R. leguminosarum 128C53, 3855, and 518 (8,15), but the genetic background of R. meliloti is quite different from the R. leguminosarum strains.…”

Section: Discussionmentioning

confidence: 99%

Sodium Stimulation of Uptake Hydrogenase Activity In Symbiotic Rhizobium

Kapulnik¹,

Phillips²

1986

Plant Physiol.

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Initial observations showed a 100% increase in Hruptake (Hup) activity of Rhizobium legumixosarum strain 3855 in pea root nodules (Pisum sativum L. cv Alaska) on plants growing in a baked clay substrate relative to those growing in vermiculite, and an investigation of nutrient factors responsible for the phenomenon was initiated. Signifiantly greater Hup activity was first measured in the clay-rown plants 24 days after germination, and higher activity was maintained relative to the vermiculite treatment until experiments were terminated at day 32. The increase in Hup activity was associated with a decrease in H2 evolution for plants with comparable rates of acetylene reduction. Analyses of the cLay showed that it contained more Na (29 versus 9 milligrams per kilogram) and less K' (6 versus 74 milligrams per kilogram) than the vermiculite. Analyses of plants, however, showed a lare increase in Na' concentration of clay-grown plants with a much smaller reduction in K concentration. In tests with the same organisms in a hydroponic system with controlled pH, 40 millimolar NaCI increased Hup activity more than 100% over plants grown in solutions lacking NaCI. Plants with increased Hup activity, however, did not have greater net carbon or total nitrogen assimilation. KCI treatments from 5 to 80 millimolar produced slight increased in Hup activity at 10 millimolar KC] and tests with other salts in the hydroponic system indicated that only Na strongly promoted Hup activity. Treating vermiculite with 50 millimolar NaCI increased Na concentration in pea plant tissue and greatly promoted Hup activity of root nodules in a manner analogous to the original observation with the clay rooting medium. A wider generality of the phenomenon was suggested by demonstrating that exogenous Na increased Hup activity of other R. kguminosarum strains and promoted Hup activity of R. meliloti strain B300 in alfalfa (Medicago sativa L.).The nitrogenase enzyme complex of procaryotes catalyzes a concurrent reduction of N2 and protons to produce NH3 and H2.Even under 5 M,4Pa of N2, the system continues to allocate at

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Characterization of hup-specific DNA in Rhizobium leguminosarum strains of different origin

Abstract: 17 Strains of Rhizobium leguminosarum which strains of diverse origin, including those which differ physiologically. This paper reports on the localization of hup-specific DNA in these physiologically-characterized strains of R. legurninosarum

Cited by 8 publications

References 9 publications

Toward More Productive, Efficient, and Competitive Nitrogen-Fixing Symbiotic Bacteria

Toward More Productive, Efficient, and Competitive Nitrogen-Fixing Symbiotic Bacteria

Occurrence of H₂-Uptake Hydrogenases in Bradyrhizobium sp. (Lupinus) and Their Expression in Nodules of Lupinus spp. and Ornithopus compressus

Sodium Stimulation of Uptake Hydrogenase Activity In Symbiotic Rhizobium

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Characterization of hup-specific DNA in Rhizobium leguminosarum strains of different origin

Abstract: 17 Strains of Rhizobium leguminosarum which strains of diverse origin, including those which differ physiologically. This paper reports on the localization of hup-specific DNA in these physiologically-characterized strains of R. legurninosarum

Cited by 8 publications

References 9 publications

Toward More Productive, Efficient, and Competitive Nitrogen-Fixing Symbiotic Bacteria

Toward More Productive, Efficient, and Competitive Nitrogen-Fixing Symbiotic Bacteria

Occurrence of H2-Uptake Hydrogenases in Bradyrhizobium sp. (Lupinus) and Their Expression in Nodules of Lupinus spp. and Ornithopus compressus

Sodium Stimulation of Uptake Hydrogenase Activity In Symbiotic Rhizobium

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Occurrence of H₂-Uptake Hydrogenases in Bradyrhizobium sp. (Lupinus) and Their Expression in Nodules of Lupinus spp. and Ornithopus compressus