Nitrogen fixation and hydrogen metabolism by Rhizobium leguminosarum isolates in pea root nodules

1981 ◽  
Vol 27 (10) ◽  
pp. 1028-1034 ◽  
Author(s):  
Louise M. Nelson ◽  
J. J. Child
Keyword(s):  
Relative Efficiency ◽  
Rhizobium Leguminosarum ◽  
High Efficiency ◽  
Root Nodules ◽  
Dry Weight ◽  
Hydrogenase Activity ◽  
Uptake Hydrogenase ◽  
Hydrogen Metabolism ◽  
N Content ◽  
Significant Uptake

A survey of 108 isolates of Rhizobium leguminosarum was conducted to determine the variation in H2 uptake and relative efficiency of N2 fixation in Pisum sativum L. root nodules and the relation of relative efficiency to plant dry weight and N content. Only 14 of the isolates exhibited significant uptake hydrogenase activity and none of these had sufficient hydrogenase activity to recycle all of the H2 produced by nitrogenase. In 74 of the isolates tested relative efficiencies of N2 fixation were less than 0.60.Twenty-nine of the isolates were ineffective, since total plant N at harvest did not differ significantly from uninoculated controls. The remaining 79 effective isolates could be divided into low-and high-efficiency groups. Plants which were inoculated with isolates from the two groups and harvested after 4 weeks did not differ significantly in plant dry weight or N content. Among the isolates with high relative efficiency of N2 fixation, two groups could be recognized: one possessing significant uptake hydrogenase activity, the other lacking hydrogenase activity but in which H2 evolution was low. Although the two groups did not differ with respect to plant dry weight or N content, the identification of this latter group may be of some significance for optimizing the efficiency of N2 fixation.

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 Host-Dependent Expression of Rhizobium leguminosarum bv. viciae Hydrogenase Is Controlled at Transcriptional and Post-Transcriptional Levels in Legume Nodules

2008 ◽  
Vol 21 (5) ◽  
pp. 597-604 ◽  
Author(s):  
Belén Brito ◽  
Annita Toffanin ◽  
Rosa-Isabel Prieto ◽  
Juan Imperial ◽  
Tomás Ruiz-Argüeso ◽  
...  
Keyword(s):  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Gene Promoter ◽  
Hydrogenase Activity ◽  
Transcription Analysis ◽  
Nickel Binding ◽  
Level Of Activity ◽  
Structural Subunit ◽  
Hup Genes ◽  
Related Proteins

The legume host affects the expression of Rhizobium leguminosarum hydrogenase activity in root nodules. High levels of symbiotic hydrogenase activity were detected in R. leguminosarum bacteroids from different hosts, with the exception of lentil (Lens culinaris). Transcription analysis showed that the NifA-regulated R. leguminosarum hydrogenase structural gene promoter (P1) is poorly induced in lentil root nodules. Replacement of the P1 promoter by the FnrN-dependent promoter of the fixN gene restored transcription of hup genes in lentil bacteroids, but not hydrogenase activity. In the PfixN-hupSL strain, additional copies of the hup gene cluster and nickel supplementation to lentil plants increased bacteroid hydrogenase activity. However, the level of activity in lentil still was significantly lower than in pea bacteroids, indicating that an additional factor is impairing hydrogenase expression inside lentil nodules. Immunological analysis revealed that lentil bacteroids contain reduced levels of both hydrogenase structural subunit HupL and nickel-binding protein HypB. Altogether, results indicate that hydrogenase expression is affected by the legume host at the level of both transcription of hydrogenase structural genes and biosynthesis or stability of nickel-related proteins HypB and HupL, and suggest the existence of a plant-dependent mechanism that affects hydrogenase activity during the symbiosis by limiting nickel availability to the bacteroid.

scholarly journals New Rhizobium leguminosarum bv. trifolii isolates: collection, identification and screening of efficiency in symbiosis with clover

2011 ◽  
Vol 52 (No. 3) ◽  
pp. 105-110 ◽  
Author(s):  
T. Šimon
Keyword(s):  
Rhizobium Leguminosarum ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Red Clover ◽  
Dry Weight ◽  
Soil Condition ◽  
Root Volume ◽  
Mean Values ◽  
Root Dry Weight ◽  
Variability Level

Suitable clover stands (field and meadow) were chosen to isolate new R. leguminosarum bv. trifolii strains. Together 49 strains were isolated, labelled and maintained. Ten primers were used for identification and amplification products were detected by agarose electrophoresis. Amplification products of individual primers did not make possible to distinguish all isolates; a combination of at least two primers was necessary. No differences in genetic variability level between field and meadow isolates were found. Hydroponic perlite experiments were used for the screening of rhizobial isolates and the tetraploid red clover variety Amos was used as a host plant. Shoots were weighed and the root volume was determined at the onset of anthesis. Total nitrogenase activity (TNA) of the symbiotic system was measured and the root dry weight was determined. High differences among individual isolates were found in all the characteristics. Statistically significant were differences among individual isolates for TNA, growth characteristics did not differ significantly. Strong positive relationships between fresh forage, dry forage, root volume and root dry weight were determined (r = 0.69–0.98; p > 0.05). Nine isolates were selected as effective, based on the mean values of all isolates screened. Selected isolates achieved the above average values in most measured characteristics. Out of the nine isolates, two were isolated from root nodules of clover cultivated in field stands, seven strains were isolated from clover grown in natural meadows. Additional study of isolates in soil condition will follow.

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.

Oxygen tolerance of uptake hydrogenase in Azospirillum spp.

1986 ◽  
Vol 32 (12) ◽  
pp. 897-900 ◽  
Author(s):  
Changlin Fu ◽  
Roger Knowles
Keyword(s):  
Stationary Phase ◽  
Hydrogenase Activity ◽  
Uptake Hydrogenase ◽  
Azospirillum Lipoferum ◽  
Oxygen Tolerance ◽  
Fold Induction ◽  
Uptake Activity ◽  
Significant Uptake

Uptake hydrogenase in Azospirillum lipoferum and A. amazonense was studied in vivo under N2-fixing and NH4Cl-grown conditions. N2-flxing cultures of both A. lipoferum and A. amazonense showed significant uptake-hydrogenase activities which reached their maximum in late log phase, N2-fixing A. amazonense had 5 times higher H2 uptake activity than N2-fixing A. lipoferum. Uptake-hydrogenase activities of both species were negligible in NH4Cl-grown cells. However, sparging with H2 during growth caused over a 100-fold induction of uptake-hydrogenase activities, and prolonged the activities into stationary phase, suggesting that hydrogenase synthesis requires exogenous H2 as inducer. Oxygen-dependent uptake-hydrogenase activity in A. amazonense was almost unaffected by 20 kPa O2, whereas in A. lipoferum and A. brasilense activities were inhibited by 40 and 100%, respectively, in 20 kPa O2. Air caused a strong repression of hydrogenase synthesis in both species. Nitrogenase was roughly equally O2 sensitive in all three species.

Hydrogen metabolism of Azospirillum brasilense in nitrogen-free medium

1980 ◽  
Vol 26 (9) ◽  
pp. 1126-1131 ◽  
Author(s):  
Y. K. Chan ◽  
L. M. Nelson ◽  
R. Knowles
Keyword(s):  
Gas Phase ◽  
Cyclic Gmp ◽  
Azospirillum Brasilense ◽  
Nitrogenase Activity ◽  
Hydrogenase Activity ◽  
Similar Response ◽  
Uptake Hydrogenase ◽  
Hydrogen Metabolism ◽  
Free Medium ◽  
Batch Cultures

Production of H2 by Azospirillum brasilense under N2-fixing conditions was studied in continuous and batch cultures. Net H2 production was consistently observed only when the gas phase contained CO. Nitrogenase activity (C2H2 reduction) and H2 evolution (in the presence of 5% CO) showed a similar response to O2 and were highest at 0.75% dissolved O2. Uptake hydrogenase activity, ranging from 0.3 to 2.5 μmol H2/mg protein per hour was observed in batch cultures under N2. Such rates were more than sufficient to recycle nitrogenase-produced H2. Tritium-exchange assay showed that H2 uptake was higher under Ar than under N2. Uptake hydrogenase was strongly inhibited by CO and C2H2. Cyclic GMP inhibited both nitrogenase and uptake hydrogenase activities.

scholarly journals Uptake Hydrogenase Activity Determined by Plasmid pRL6JI in Rhizobium leguminosarum Does Not Increase Symbiotic Nitrogen Fixation

1985 ◽  
Vol 50 (4) ◽  
pp. 791-794 ◽  
Author(s):  
Scott D. Cunningham ◽  
Yoram Kapulnik ◽  
Nicholas J. Brewin ◽  
Donald A. Phillips
Keyword(s):  
Nitrogen Fixation ◽  
Rhizobium Leguminosarum ◽  
Symbiotic Nitrogen Fixation ◽  
Hydrogenase Activity ◽  
Uptake Hydrogenase

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.

scholarly journals Uptake hydrogenase activity and ATP formation in Rhizobium leguminosarum bacteroids.

1982 ◽  
Vol 151 (2) ◽  
pp. 989-995 ◽  
Author(s):  
L M Nelson ◽  
S O Salminen
Keyword(s):  
Rhizobium Leguminosarum ◽  
Hydrogenase Activity ◽  
Uptake Hydrogenase ◽  
Atp Formation
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