Interaction between hydrogenase, nitrogenase, and respiratory activities in a Frankia isolate from Alnus rubra

1989 ◽  
Vol 35 (6) ◽  
pp. 636-641 ◽  
Author(s):  
Marcia A. Murry ◽  
Mary F. Lopez
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Root Nodules ◽  
Hydrogenase Activity ◽  
Alnus Rubra ◽  
Uptake Hydrogenase ◽  
Frankia Strain ◽  
Intact Cells

H2 uptake and H2-supported O2 uptake were measured in N2-fixing cultures of Frankia strain ArI3 isolated from root nodules of Alnus rubra. H2 uptake by intact cells was O2 dependent and maximum rates were observed at ambient O2 concentrations. No hydrogenase activity could be detected in [Formula: see text], undifferentiated filaments cultured aerobically indicating that uptake hydrogenase activity was associated with the vesicles, the cellular site of nitrogen fixation in Frankia. Hydrogenase activity was inhibited by acetylene but inhibition could be alleviated by pretreatment with H2. H2 stimulated acetylene reduction at supraoptimal but not suboptimal O2 concentrations. These results suggest that uptake hydrogenase activity in ArI3 may play a role in O2 protection of nitrogenase, especially under conditions of carbon limitation.Key words: Frankia, hydrogenase, nitrogenase, O2 protection.

Pisum sativum cultivar effects on hydrogen metabolism in Rhizobium

1984 ◽  
Vol 62 (8) ◽  
pp. 1682-1686 ◽  
Author(s):  
Eulogio J. Bedmar ◽  
Donald A. Phillips
Keyword(s):  
Pisum Sativum ◽  
Relative Efficiency ◽  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Developmental Differences ◽  
The Other ◽  
Hydrogenase Activity ◽  
Uptake Hydrogenase ◽  
Hydrogen Metabolism ◽  
Pisum Sativum L

Data from 14 Pisum sativum L. cultivars establish that three pea genotypes, which were previously reported to affect net H2 evolution from root nodules in air and uptake hydrogenase activity of Rhizobium leguminosarum 128C53, are not unique. Two pea lines, 'JI1205' and 'Green Arrow,' produced very active uptake hydrogenase activity in strain 128C53, and essentially no H2 was evolved in air from root nodules capable of reducing 20 μmol C2H2 ∙ plan−1 ∙ h−1. Five other cultivars produced significantly lower uptake hydrogenase activities in the same bacterial strain and had much higher rates of net H2 evolution with similar C2H2-reduction capabilities. Parallel experiments with the same cultivars nodulated by R. leguminosarum 300, an organism with no convincing uptake hydrogenase activity in any pea line, showed that 'JI1205' and 'Green Arrow' had a significantly lower relative efficiency (RE) of N2 fixation (1 − (H2 evolved in air/C2H2 reduced)) than the other five cultivars. Developmental differences among the pea lines prevented any conclusion about the advantages or disadvantages of uptake hydrogenase activity for plant growth, but in general, cultivars with high uptake hydrogenase activity and low net H2 evolution grew more slowly than those evolving large amounts of H2.

scholarly journals Introduction of H2-Uptake Hydrogenase Genes Into Rhizobial Strains Improves Symbiotic Nitrogen Fixation in Vicia sativa and Lotus corniculatus Forage Legumes

2021 ◽  
Vol 3 ◽  
Author(s):  
Mariana Sotelo ◽  
Ana Claudia Ureta ◽  
Socorro Muñoz ◽  
Juan Sanjuán ◽  
Jorge Monza ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Rhizobium Leguminosarum ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Lotus Corniculatus ◽  
Vicia Sativa ◽  
Uptake Hydrogenase ◽  
Forage Crops ◽  
Mesorhizobium Loti

Biological nitrogen fixation by the Rhizobium-legume symbiosis allows the conversion of atmospheric nitrogen into ammonia within root nodules mediated by the nitrogenase enzyme. Nitrogenase activity results in the evolution of hydrogen as a result of a side reaction intrinsic to the activity of this enzyme. Some rhizobia, and also other nitrogen fixers, induce a NiFe uptake hydrogenase (Hup) to recycle hydrogen produced by nitrogenase, thus improving the efficiency of the nitrogen fixation process. In this work we report the generation and symbiotic behavior of hydrogenase-positive Rhizobium leguminosarum and Mesorhizobium loti strains effective in vetch (Vicia sativa) and birsfoot trefoil (Lotus corniculatus) forage crops, respectively. The ability of hydrogen recycling was transferred to these strains through the incorporation of hup minitransposon TnHB100, thus leading to full recycling of hydrogen in nodules. Inoculation of Vicia and Lotus plants with these engineered strains led to significant increases in the levels of nitrogen incorporated into the host legumes. The level of improvement of symbiotic performance was dependent on the recipient strain and also on the legume host. These results indicate that hydrogen recycling has the potential to improve symbiotic nitrogen fixation in forage plants.

Nitrogen Fixation by Native Australian Legumes

1981 ◽  
Vol 29 (2) ◽  
pp. 143 ◽  
Author(s):  
AC Lawrie
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Sand Dune ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Sand Dunes ◽  
Late Summer ◽  
Open Forest ◽  
Seasonal And Diurnal Variations ◽  
Major Factors

Nitrogen fixation was studied by the acetylene-reduction technique in root nodules of 10 native Australian legumes in three habitats in Victoria: low open-forest. sandy heathland and coastal sand dunes. Nodular activity reached a maximum in spring (and in autumn in sand-dune species), declined to a minimum in late summer and continued at a low level throughout winter. Mean nitrogenase activity was 1.73 μmol C2H2 reduced g-1 fresh wt nodules h-1, with spring maxima 8-250 times summer minima. It is suggested that variations in rainfall and temperature were the major factors influencing seasonal variations in nodular activity. Estiniates of minimum acetylene reduction per hectare per year were derived from measurements of seasonal and diurnal variations in acetylene reduction and abundance of nodules per hectare, and were used to derive approximate minimum values for nitrogen fixation of 0.004-0.746 kg ha-1 yr-1. The quantities of nitrogen fixed are compared with other reports and the significance of nitrogen fixation by these native legumes is discussed.

An effective strain of Frankia from Casuarina sp.

1983 ◽  
Vol 61 (11) ◽  
pp. 2815-2821 ◽  
Author(s):  
H. G. Diem ◽  
D. Gauthier ◽  
Y. Dommergues
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Pure Culture ◽  
Root Nodules ◽  
Effective Strain ◽  
Root Hairs ◽  
Culture Conditions ◽  
Reduction Technique ◽  
Standard Culture

A strain of Frankia, designated Cj1-82, from root nodules of a hybrid of Casuarina junghuhniana and C. equisetifolia has been isolated in pure culture. When grown under standard culture conditions, Cj1-82 exhibited the following characteristics: cushionlike colonies with short, wide hyphae and, in addition to typical sporangia, intercalary elongated sporangialike structures (SLS) which could be disrupted into sporelike units. No vesicles were found. When inoculated into the rhizosphere of C. equisetifolia, Cj1-82 produced vesicles. Reinfection of seedlings of C. equisetifolia was achieved repeatedly with inocula prepared from a suspension of Cj1-82. Sequences of infection of root hairs were described. Fourteen days after inoculation, nodules were apparent on the roots. Nodules were shown to be effective in nitrogen fixation as assessed by the acetylene-reduction technique.

Acetylene reduction and hydrogen evolution by nitrogenase in a Rhizobium–legume symbiosis

1983 ◽  
Vol 61 (3) ◽  
pp. 780-785 ◽  
Author(s):  
Scott A. Edie
Keyword(s):  
Hydrogen Evolution ◽  
Acetylene Reduction ◽  
Rhizobium Leguminosarum ◽  
High Light ◽  
Hydrogenase Activity ◽  
Uptake Hydrogenase ◽  
Vegetative Phase ◽  
Pisum Sativum L ◽  
Legume Symbiosis ◽  
The Relationship

The relationship between acetylene reduction and hydrogen evolution in air was examined in peas (Pisum sativum L. cv. Alaska) inoculated with Rhizobium leguminosarum strain 3740, which lacked uptake hydrogenase activity (Hup−). In the absence of a system for recycling hydrogen, changes in the relative efficiency of N2 fixation (RE), which is defined as RE = 1 − (hydrogen evolved in air)/(acetylene reduced), presumably reflect an altered capacity of nitrogenase to allocate electrons between protons and N2. The RE of plants grown without combined nitrogen declined during the vegetative phase of growth and increased after flowering. Continuous high light or elevated CO2 conditions in the absence of nitrate maintained throughout ontogeny accentuated decreases in RE. When nitrate was present in the growth medium declines in RE during the vegetative phase were lessened. These results are consistent with the concept that the electron allocation coefficient of nitrogenase varies in the absence of uptake hydrogenase activity.

The role of oxygen diffusion from the shoots and nodule roots in nitrogen fixation by root nodules of Myrica gale

1978 ◽  
Vol 56 (11) ◽  
pp. 1365-1371 ◽  
Author(s):  
John Tjepkema
Keyword(s):  
Nitrogen Fixation ◽  
Oxygen Uptake ◽  
Aqueous Phase ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Myrica Gale ◽  
Before And After ◽  
Whole Plants

Nitrogenase activity (acetylene reduction) and oxygen uptake by root nodules of Myrica gale L. were measured before and after removal of nodule roots. There was no significant effect of nodule root removal when respiration was measured in the gas phase (0.05–0.2 atm pO2 (1 atm = 101.325 kPa)) or acetylene reduction in a stirred aqueous phase at 0.2 atm pO2. However, when acetylene reduction was measured in 0.05 atm pO2 in an unstirred aqueous phase, there was a 66 to 76% reduction in activity. These results indicate that nodule roots are important for oxygen uptake when the nodules are present in an aqueous phase at low pO2, which is probably the normal environmental conditions for many of the nodules. Other measurements showed that diffusion of oxygen from the shoot to the root nodules is not important for nitrogen fixation. These measurements were done on whole plants with the shoots in air (0.20 atm pO2) and the roots in water at the desired pO2 value. With 0.0 atmpO2 in the root environment, the rate of acetylene reduction was only 4% of the rate at 0.2 atmpO2. Thus, only small amounts of oxygen are transported from the shoot to the nodules.

A comparison of carbon source utilization for growth and nitrogenase activity in two Frankia isolates

1986 ◽  
Vol 32 (4) ◽  
pp. 353-358 ◽  
Author(s):  
Mary F. Lopez ◽  
Patricia Young ◽  
John G. Torrey
Keyword(s):  
Nitrogen Fixation ◽  
Carbon Source ◽  
Oxygen Uptake ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Carbon Sources ◽  
Alnus Rubra ◽  
Nitrogen Fixing ◽  
Pure Cultures

The carbon source requirements for the growth and nitrogen fixation of two morphologically distinct Frankia isolates were examined. Isolate ArI3 (from Alnus rubra) grew well on propionate, malate, acetate, and trehalose, and isolate CcI2 (from Casuarina cunninghamiana) grew best on pyruvate, acetate, and propionate. In general, the same carbon sources that supported growth supported both the development of vesicles and nitrogenase activity in long-term induction experiments in both isolates. However, ArI3 cultures induced on proprionate had 7 to 26 times the activity of other carbon sources and ArI3 cultures induced on acetate did not develop any detectable acetylene reduction. In a parallel set of experiments, cultures of both isolates were induced for nitrogenase activity on propionate and the resulting nitrogen fixing cultures were washed free of the organic acid by centrifugation. The washed cultures were incubated in the presence of various carbon sources to determine the ability of a particular substrate to supply energy directly for nitrogen fixation when vesicles and nitrogenase were already present. As was observed in the long-term induction experiments, pyruvate, propionate, and acetate supported the greatest activity in CcI2. Succinate and malate supported the greatest activity in ArI3, and propionate had very little stimulation of acetylene reduction. The reason for the lack of stimulation by propionate for washed cells of ArI3 was unclear but may have been due to toxic concentrations of the organic acid. In an attempt to compare the carbon utilization of ArI3 in pure culture with that in the alder symbiosis, oxygen uptake in the presence of various carbon sources of vesicles clusters isolate from Alnus rubra nodules inoculated with ArI3 was compared with the oxygen uptake of nitrogen-fixing pure cultures of ArI3. The oxygen uptake of the isolated vesicle clusters was stimulated by sucrose, trehalose, and glucose, but not by a variety of organic acids. In comparison, nitrogen-fixing pure cultures of ArI3 readily oxidized sugars and organic acids.

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