Strain of Rhizobium lupini determines natural abundance of 15N in root nodules of Lupinus spp

Bergersen, F. J.; Turner, G. L.; Amarger, Noëlle; Mariotti, Françoise; Mariotti, André

doi:10.1016/0038-0717(86)90109-4

Cited by 40 publications

(12 citation statements)

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“…against ^''N ( Table 1). Several authors have demonstrated that the fractionation during Nj-fixation is influenced by the bacterial strain (Steele et aL, 1983;Bergersen et aL, 1986;Ledgard, 1989), snd Ledgard (1989) provided evidence that nutrient supply and soil moisture also influence the fractionation factor. According to data assembled by Peoples et al (1989) from studies of 12 genotypes of nodulated legumes grown on media free of combined N, shoots were only slightly depleted m ^'N (-0 65±O-2^i«, P > 0-01), w^hereas whole plants were not depleted at all ( -0-07 + 0-12°^).…”

Section: Specific Processes {A) N Mineralizationmentioning

confidence: 99%

Tansley Review No. 95¹⁵N natural abundance in soil‐plant systems

1997

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summary Equilibrium and kinetic isotope fractionations during incomplete reactions result in minute differences in the ratio between the two stable X isotopes, 15N and 14N, in various N pools. In ecosystems such variations (usually expressed in per mil [δ15N] deviations from the standard atmospheric N2) depend on isotopic signatures of inputs and outputs, the input‐output balance, N transformations and their specific isotope effects, and compartmentation of N within the system. Products along a sequence of reactions, e.g. the N mineralization‐N uptake pathway, should, if fractionation factors were equal for the different reactions, become progressively depleted. However, fractionation factors van. For example, because nitrification discriminates against 15N in the substrate more than does N mineralization, NH4+can become isotopically heavier than the organic N from which it is derived. Levels of isotopic enrichment depend dynamically on the stoichiometry of reactions, as well as on specific abiotic and biotic conditions. Thus, the δ15N of a specific N pool is not a constant, and 15N of a N compound added to the system is not a conservative, unchanging tracer. This fact, together with analytical problems of measuring 15N in small and dynamic pools of N in the soil‐plant system, and the complexity of the X cycle itself (for instance the abundance of reversible reactions), limit the possibilities of making inferences based on observations of 15N abundance in one or a few pools of N in a system. Nevertheless, measurements of δ15N might offer the advantage of giving insights into the N cycle without disturbing the system by adding 15N tracer. Such attempts require, however, that the complex factors affecting 15N in plants be taken into account, viz. (i) the source(s) of N (soil, precipitation, NOX, NH3, N2‐fixation), (ii) the depth(s) in soil from which N is taken up, (iii) the form(s) of soil‐N used (organic N, NH4+, NO3−), (iv) influences of mycorrhizal symbioses and fractionations during and after N uptake by plants, and (v) interactions between these factors and plant phenology. Because of this complexity, data on δ15N can only be used alone when certain requirements are met, e.g. when a clearly discrete N source in terms of amount and isotopic signature is studied. For example, it is recommended that N in non‐N2‐fixing species should differ more than 5% from N derived by N2‐fixation, and that several non‐N2‐fixing references are used, when data on δ15N are used to estimate Na‐fixation in poorly described ecosystems. As well as giving information on N source effects, δ15N can give insights into N cycle rates. For example, high levels of N deposition onto previously N‐limited systems leads to increased nitrification, which produces 15N‐enriched NH4 and N‐depleted NO3. As many forest plants prefer NH4−they become enriched in 15N in such circumstances. This change in plant 15N will subsequently also occur in the soil surface horizon after litter‐fall, and might be a useful indicator of N saturation, especially since ...

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Section: Specific Processes {A) N Mineralizationmentioning

confidence: 99%

Tansley Review No. 95¹⁵N natural abundance in soil‐plant systems

1997

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“…Furthermore transporters (leghaemoglobins) for O 2 are present, and facilitated transport across the peribacteroid membrane is likely for O 2 (Strodtman & Emerich, ), yet there has been no suggestion of any facilitated N 2 transport within nodules. Against these encouragements, a model of nodule function suggested no N 2 limitation to nitrogenase in legume nodules (Bergersen, ), although an earlier paper by the same author (Bergersen et al ., ) showed no N isotope fractionation. Further work is undoubtedly required to reconcile the observations indicating no isotope fractionation and models of nodule function.…”

Section: δ15n (‰) Of Pot Cultured Whole Legume Plants Totally Dependementioning

confidence: 99%

Isotope discrimination provides new insight into biological nitrogen fixation

Unkovich

2013

New Phytologist

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“…Coronilla varia Phylogenetic analysis of nodC and nifH genes Bergersen et al (1986) * The 16S rDNA types were characterized by RFLP analysis of PCR-amplified 16S rRNA genes as previously reported . † The biovars indicated within quotation marks were identified in this study on the basis of the analysis of the Sym genes.…”

Section: Msdj 2184mentioning

confidence: 99%

Classification of rhizobia based on nodC and nifH gene analysis reveals a close phylogenetic relationship among Phaseolus vulgaris symbionts The GenBank accession numbers for the sequences reported in this paper are AF217261 through AF217272 for nodC and AF218126, AF275670 and AF275671 for nifH.

et al. 2001

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The nodC and nifH genes were characterized in a collection of 83 rhizobial strains which represented 23 recognized species distributed in the genera Rhizobium, Sinorhizobium, Mesorhizobium and Bradyrhizobium, as well as unclassified rhizobia from various host legumes. Conserved primers were designed from available nucleotide sequences and were able to amplify nodC and nifH fragments of about 930 bp and 780 bp, respectively, from most of the strains investigated. RFLP analysis of the PCR products resulted in a classification of these rhizobia which was in general well-correlated with their known host range and independent of their taxonomic status. The nodC and nifH fragments were sequenced for representative strains belonging to different genera and species, most of which originated from Phaseolus vulgaris nodules. Phylogenetic trees were constructed and revealed close relationships among symbiotic genes of the Phaseolus symbionts, irrespective of their 16S-rDNA-based classification. The nodC and nifH phylogenies were generally similar, but cases of incongruence were detected, suggesting that genetic rearrangements have occurred in the course of evolution. The results support the view that lateral genetic transfer across rhizobial species and, in some instances, across Rhizobium and Sinorhizobium genera plays a role in diversification and in structuring the natural populations of rhizobia.

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Strain of Rhizobium lupini determines natural abundance of 15N in root nodules of Lupinus spp

Cited by 40 publications

References 5 publications

Tansley Review No. 95¹⁵N natural abundance in soil‐plant systems

Tansley Review No. 95¹⁵N natural abundance in soil‐plant systems

Isotope discrimination provides new insight into biological nitrogen fixation

Classification of rhizobia based on nodC and nifH gene analysis reveals a close phylogenetic relationship among Phaseolus vulgaris symbionts The GenBank accession numbers for the sequences reported in this paper are AF217261 through AF217272 for nodC and AF218126, AF275670 and AF275671 for nifH.

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Strain of Rhizobium lupini determines natural abundance of 15N in root nodules of Lupinus spp

Cited by 40 publications

References 5 publications

Tansley Review No. 9515N natural abundance in soil‐plant systems

Tansley Review No. 9515N natural abundance in soil‐plant systems

Isotope discrimination provides new insight into biological nitrogen fixation

Classification of rhizobia based on nodC and nifH gene analysis reveals a close phylogenetic relationship among Phaseolus vulgaris symbionts The GenBank accession numbers for the sequences reported in this paper are AF217261 through AF217272 for nodC and AF218126, AF275670 and AF275671 for nifH.

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Tansley Review No. 95¹⁵N natural abundance in soil‐plant systems

Tansley Review No. 95¹⁵N natural abundance in soil‐plant systems