scholarly journals Effect of carbaryl and 2,4-D to nitrogenase and uptake hydrogenase in agar cultures and root nodules formed by Rhizobium leguminosarum.

1994 ◽  
Vol 40 (6) ◽  
pp. 569-574 ◽  
Author(s):  
DINESH K. MAHESHWARI ◽  
MEENU SARAF
1984 ◽  
Vol 62 (8) ◽  
pp. 1682-1686 ◽  
Author(s):  
Eulogio J. Bedmar ◽  
Donald A. Phillips

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.


2021 ◽  
Vol 3 ◽  
Author(s):  
Mariana Sotelo ◽  
Ana Claudia Ureta ◽  
Socorro Muñoz ◽  
Juan Sanjuán ◽  
Jorge Monza ◽  
...  

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.


1981 ◽  
Vol 27 (10) ◽  
pp. 1028-1034 ◽  
Author(s):  
Louise M. Nelson ◽  
J. J. Child

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.


2019 ◽  
Vol 70 (1) ◽  
pp. 59-67
Author(s):  
Anna Lenart-Boroń ◽  
Tadeusz Zając ◽  
Piotr Mateusz Boroń ◽  
Agnieszka Klimek-Kopyra

SummaryThe bacterial nodulation (nod) genes are essential in the formation process of root nodules. This study was aimed to verify the occurrence of nodule-associated bacteria in two pea varieties (“Tarchalska” and “Klif ”) inoculated withRhizobiuminoculants – Nitragine™ and a noncommercial one produced by the Polish Institute of Soil Science and Plant Cultivation (IUNG). The number of colonies isolated on yeast extract mannitol (YEM) agar from the nodules of “Klif ” inoculated with IUNG inoculants was significantly higher than the number of colonies isolated from other variants. Species identification was based on sequencing of 16S rDNA, which revealed that despite careful sterilization of nodules, sequences of other bacterial species were detected. Among them, one sequence belonged toRhizobium leguminosarum(isolated from IUNG inoculant). To assess the presence of nodulation-capableRhizobium, amplification of thenodCgene was performed, which revealed that of 29 samples, 19 were positive. The remaining isolates, including reference strain and bacteria isolated from Nitragine™, lacked this gene. The results show that pea nodules harbor a very diverse community of bacteria. The lack ofnodCgene in some strains isolated from plants inoculated with Nitragine™ and with IUNG inoculant proves that even ifR. leguminosarumare abundant, they may not be efficient in nodulation.


2017 ◽  
Vol 63 (5) ◽  
pp. 450-463 ◽  
Author(s):  
Zoulikha Bouchiba ◽  
Zineb Faiza Boukhatem ◽  
Zohra Ighilhariz ◽  
Nouria Derkaoui ◽  
Benaissa Kerdouh ◽  
...  

A total of 51 bacterial strains were isolated from root nodules of Scorpiurus muricatus sampled from 6 regions of western Algeria. Strain diversity was assessed by rep-PCR amplification fingerprinting, which grouped the isolates into 28 different clusters. Partial nucleotide sequencing of the 16S rRNA gene and BLAST analysis revealed that root nodules of S. muricatus were colonized by different species close to Rhizobium vignae, Rhizobium radiobacter, Rhizobium leguminosarum, Phyllobacterium ifriqiyense, Phyllobacterium endophyticum, Starkeya sp., and Pseudomonas sp. However, none of these strains was able to form nodules on its host plant; even nodC was present in a single strain (SMT8a). The inoculation test showed a great improvement in the growth of inoculated plants compared with noninoculated control plants. A significant amount of indole acetic acid was produced by some strains, but only 2 strains could solubilize phosphate. In this report we described for the first time the diversity of bacteria isolated from root nodules of S. muricatus growing in different regions in western Algeria and demonstrated their potential use in promoting plant growth.


2018 ◽  
Vol 31 (5) ◽  
pp. 568-575 ◽  
Author(s):  
Marta Robledo ◽  
Esther Menéndez ◽  
Jose Ignacio Jiménez-Zurdo ◽  
Raúl Rivas ◽  
Encarna Velázquez ◽  
...  

The infection of legume plants by rhizobia is tightly regulated to ensure accurate bacterial penetration, infection, and development of functionally efficient nitrogen-fixing root nodules. Rhizobial Nod factors (NF) have key roles in the elicitation of nodulation signaling. Infection of white clover roots also involves the tightly regulated specific breakdown of the noncrystalline apex of cell walls in growing root hairs, which is mediated by Rhizobium leguminosarum bv. trifolii cellulase CelC2. Here, we have analyzed the impact of this endoglucanase on symbiotic signaling in the model legume Medicago truncatula. Ensifer meliloti constitutively expressing celC gene exhibited delayed nodulation and elicited aberrant ineffective nodules, hampering plant growth in the absence of nitrogen. Cotreatment of roots with NF and CelC2 altered Ca2+ spiking in root hairs and induction of the early nodulin gene ENOD11. Our data suggest that CelC2 alters early signaling between partners in the rhizobia-legume interaction.


2017 ◽  
Vol 30 (4) ◽  
pp. 312-324 ◽  
Author(s):  
George C. diCenzo ◽  
Maryam Zamani ◽  
Hannah N. Ludwig ◽  
Turlough M. Finan

The bacterium Sinorhizobium meliloti Rm2011 forms N2-fixing root nodules on alfalfa and other leguminous plants. The pSymB chromid contains a 110-kb region (the ETR region) showing high synteny to a chromosomally located region in Sinorhizobium fredii NGR234 and related rhizobia. We recently introduced the ETR region from S. fredii NGR234 into the S. meliloti chromosome. Here, we report that, unexpectedly, the S. fredii NGR234 ETR region did not complement deletion of the S. meliloti ETR region in symbiosis with Medicago sativa. This phenotype was due to the bacA gene of NGR234 not being functionally interchangeable with the S. meliloti bacA gene during M. sativa symbiosis. Further analysis revealed that, whereas bacA genes from S. fredii or Rhizobium leguminosarum bv. viciae 3841 failed to complement the Fix− phenotype of a S. meliloti bacA mutant with M. sativa, they allowed for further developmental progression prior to a loss of viability. In contrast, with Melilotus alba, bacA from S. fredii and R. leguminosarum supported N2 fixation by a S. meliloti bacA mutant. Additionally, the S. meliloti bacA gene can support N2 fixation of a R. leguminosarum bacA mutant during symbiosis with Pisum sativum. A phylogeny of BacA proteins illustrated that S. meliloti BacA has rapidly diverged from most rhizobia and has converged toward the sequence of pathogenic genera Brucella and Escherichia. These data suggest that the S. meliloti BacA has evolved toward a specific interaction with Medicago and highlights the limitations of using a single model system for the study of complex biological topics.


1995 ◽  
Vol 50 (7-8) ◽  
pp. 543-551
Author(s):  
Bernhard Epping ◽  
Alexander P. Hansen ◽  
Peter Martin

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.


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