scholarly journals Effect of Increases in Oxygen Concentration during the Argon-Induced Decline in Nitrogenase Activity in Root Nodules of Soybean

1991 ◽  
Vol 96 (2) ◽  
pp. 376-381 ◽  
Author(s):  
Bryan J. King ◽  
David B. Layzell
Keyword(s):  
Oxygen Concentration ◽  
Nitrogenase Activity ◽  
Root Nodules

scholarly journals Paraburkholderia phymatum Homocitrate Synthase NifV Plays a Key Role for Nitrogenase Activity during Symbiosis with Papilionoids and in Free-Living Growth Conditions

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 952
Author(s):  
Paula Bellés-Sancho ◽  
Martina Lardi ◽  
Yilei Liu ◽  
Sebastian Hug ◽  
Marta Adriana Pinto-Carbó ◽  
...  
Keyword(s):  
Nitrogenase Activity ◽  
Root Nodules ◽  
Growth Conditions ◽  
Lysine Biosynthesis ◽  
Metabolome Analysis ◽  
Plant Host ◽  
Free Living ◽  
Bacterial Enzyme ◽  
Homocitrate Synthase ◽  
Iron Molybdenum Cofactor

Homocitrate is an essential component of the iron-molybdenum cofactor of nitrogenase, the bacterial enzyme that catalyzes the reduction of dinitrogen (N2) to ammonia. In nitrogen-fixing and nodulating alpha-rhizobia, homocitrate is usually provided to bacteroids in root nodules by their plant host. In contrast, non-nodulating free-living diazotrophs encode the homocitrate synthase (NifV) and reduce N2 in nitrogen-limiting free-living conditions. Paraburkholderia phymatum STM815 is a beta-rhizobial strain, which can enter symbiosis with a broad range of legumes, including papilionoids and mimosoids. In contrast to most alpha-rhizobia, which lack nifV, P. phymatum harbors a copy of nifV on its symbiotic plasmid. We show here that P. phymatum nifV is essential for nitrogenase activity both in root nodules of papilionoid plants and in free-living growth conditions. Notably, nifV was dispensable in nodules of Mimosa pudica despite the fact that the gene was highly expressed during symbiosis with all tested papilionoid and mimosoid plants. A metabolome analysis of papilionoid and mimosoid root nodules infected with the P. phymatum wild-type strain revealed that among the approximately 400 measured metabolites, homocitrate and other metabolites involved in lysine biosynthesis and degradation have accumulated in all plant nodules compared to uninfected roots, suggesting an important role of these metabolites during symbiosis.

scholarly journals Diffusion Limitation of Oxygen Uptake and Nitrogenase Activity in the Root Nodules of Parasponia rigida Merr. and Perry

1982 ◽  
Vol 69 (3) ◽  
pp. 728-733 ◽  
Author(s):  
John D. Tjepkema ◽  
Robert J. Cartica
Keyword(s):  
Oxygen Uptake ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Diffusion Limitation

Carbon Costs of Nitrogenase Activity in Legume Root Nodules determined using Acetylene and Oxygen

1983 ◽  
Vol 34 (8) ◽  
pp. 951-963 ◽  
Author(s):  
J. F. WITTY ◽  
F. R. MINCHIN ◽  
J. E. SHEEHY
Keyword(s):  
Nitrogenase Activity ◽  
Root Nodules ◽  
Carbon Costs

Seasonal pattern of energy use, respiration, and nitrogenase activity in root nodules of Myrica gale

1983 ◽  
Vol 61 (11) ◽  
pp. 2937-2942 ◽  
Author(s):  
Christa R. Schwintzer ◽  
John D. Tjepkema
Keyword(s):  
Energy Cost ◽  
Energy Use ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Seasonal Pattern ◽  
Uptake Ratio ◽  
Experimental Conditions ◽  
Myrica Gale ◽  
Net Production ◽  
N Requirement

Annual CO2 evolution, H2 evolution, and C2H2 reduction were measured in root nodules from a vigorous Myrica gale stand in a Massachusetts peatland at 3-week intervals in 1980. Nodule activity was approximately the same under the experimental conditions (excised nodules reducing C2H2) as in nature (attached nodules reducing N2) and the CO2 evolution to O2 uptake ratio averaged 1.07. Nitrogenase activity was first detectable in late May, reached its maximum [Formula: see text] in mid-July, and disappeared in late October. The seasonal pattern of CO2 evolution was similar except that it continued at low rates when nitrogenase activity was absent. Hydrogen evolution was barely detectable. The energy cost of nitrogen fixation, expressed as the molar CO2:C2H4 ratio, was relatively low [Formula: see text] throughout the period of substantial nitrogenase activity and had a mean annual value of 4.9. Annual N2 fixation was estimated to be 2.8 g N m−2year−1, contributing about 33% of the annual N requirement measured in 1979. Annual C use by nodules was about 21.0 g C m−2 year−1. If this C were available for additional net production, it would increase it by about 5.5%.

scholarly journals Oxygen concentration, nitrogenase activity and heterocyst frequency in the leaf cavities ofAzolla filiculoidesLam

1989 ◽  
Vol 59 (3) ◽  
pp. 283-287 ◽  
Author(s):  
M. Grilli Caiola ◽  
A. Canini ◽  
D. Moscone
Keyword(s):  
Oxygen Concentration ◽  
Nitrogenase Activity ◽  
Heterocyst Frequency

Characterization of an ineffective actinorhizal microsymbiont, Frankia sp. EuI1 (Actinomycetales)

1980 ◽  
Vol 26 (9) ◽  
pp. 1072-1089 ◽  
Author(s):  
Dwight Baker ◽  
William Newcomb ◽  
John G. Torrey
Keyword(s):  
Host Range ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Host Cells ◽  
Vesicle Formation ◽  
Nitrogen Fixing ◽  
Elaeagnus Umbellata

The actinomycete, Frankia sp. EuI1, isolated from root nodules of Elaeagnus umbellata is an infective endophyte but which lacks the ability to form an effective nitrogen-fixing symbiosis with its host. This ineffective organism can be distinguished easily from other frankiae, in vitro, on the basis of size, morphology, and the elaboration of a diffusible pigment. Cross-inoculation studies indicated that the host range of this symbiont is narrow and probably restricted to the Elaeagnaceae. In all cases of nodulation the symbiosis never developed nitrogenase activity and the microsymbiont never produced endophytic vesicles within the infected host cells. Sporangia were produced in vivo and in vitro so the morphogenetic block is apparently restricted to vesicle formation.

scholarly journals Effects of Carbohydrate on the Internal Oxygen Concentration, Oxygen Uptake, and Nitrogenase Activity in Detached Pea Nodules

1989 ◽  
Vol 91 (2) ◽  
pp. 603-609 ◽  
Author(s):  
Jonathan D. Monroe ◽  
Thomas A. LaRue
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Nitrogenase Activity

Relationship between Activities of Enzymes for the Removal of O2·- and H2O2 and Nitrogenase in Root Nodules of Phaseolus vulgaris L.

1995 ◽  
Vol 50 (7-8) ◽  
pp. 543-551
Author(s):  
Bernhard Epping ◽  
Alexander P. Hansen ◽  
Peter Martin
Keyword(s):  
Superoxide Dismutase ◽  
Phaseolus Vulgaris ◽  
Ascorbate Peroxidase ◽  
Peroxidase Activity ◽  
Rhizobium Leguminosarum ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Hypersensitive Reaction ◽  
Guaiacol Peroxidase ◽  
Bacterial Strains

Abstract Nodules of Rhizobium leguminosarum bv. phaseoli in symbiosis with Phaseolus vulgaris were compared with regard to their nitrogenase activity and activities of enzymes involved in the removal of O2·- and H2O2 as well as total ascorbate content. Activities of catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11), and total ascorbate content were consist­ently higher in nodules inhabited by bacterial strains with higher nitrogenase activity. Values for superoxide dismutase (EC 1.15.11), and guaiacol peroxidase activity did not differ for the bacterial strains compared. On the other hand, when different plant cultivars were inoculated with the same bacterial strain, high nitrogenase activity did not correlate with a higher activ­ity of the oxygen scavenging enzyms or a higher content of total ascorbate. In this case, values for guaiacol peroxidase activity were greatly enhanced in nodules with lower nitrogen­ ase activity. This may be part of a hypersensitive reaction of the plant cultivar against the bacterial symbiotic partner. Inhibition of catalase activity in the nodules by addition of triazole to the nutrient solution did not alter nitrogenase activity within the first nine hours after addition. It can be concluded that the activity of catalase, ascorbate peroxidase, and superoxide dismutase is not generally coupled to nitrogenase activity in root nodules of P. vulgaris.

scholarly journals Factors Influencing Nitrogenase Activity (Acetylene Reduction) by Root Nodules of Groundnut, Arachis hypogaea L.

1983 ◽  
Vol 10 (1) ◽  
pp. 26-29 ◽  
Author(s):  
P. T. C. Nambiar ◽  
P. J. Dart
Keyword(s):  
Soil Moisture ◽  
Environmental Factors ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Activity Period ◽  
Diurnal Fluctuation ◽  
Factors Influencing ◽  
Arachis Hypogaea L ◽  
Reduction Assay

Abstract Acetylene reduction assay, used to measure nitrogenase activity of legume root nodules, is influenced by environmental factors, which limit its application. The effects of some of the environmental factors on acetylene reduction by groundnut root nodules are described. The activity was nonlinear during the first hour of incubation. Assay temperature above 25 C decreased the activity. Washing the nodulated roots prior to the assay also decreased the activity. The activity was influenced by light intensity, soil moisture, and moisture content in the incubation bottle. Diurnal fluctuation with one maximum and one minimum activity period during a 24 hour cycle was observed. Nitrogenase activity was higher during the postrainy season compared to that of the rainy season. A virginia cultivar Kadiri-71 had higher nitrogenase activity than a dwarf valencia cultivar, MH 2.

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