Nodulation and symbiotic nitrogen fixation by genotypes of blackgram [Vigna mungo (L.) Hepper] as affected by fertiliser nitrogen

2002 ◽  
Vol 53 (4) ◽  
pp. 453
Author(s):  
B. Singh ◽  
K. Usha
Keyword(s):  
Nitrogen Fixation ◽  
Symbiotic Nitrogen Fixation ◽  
Unit Area ◽  
Reductase Activity ◽  
Farming Systems ◽  
Vigna Mungo ◽  
Atmospheric Nitrogen ◽  
Nitrogen Treatments ◽  
Nitrite Content ◽  
Applied Nitrogen

Intercropping with legumes and non-legumes is commonly practised in many parts of the world to maximise productivity per unit area of land. In India, blackgram or urd [Vigna mungo (L.) Hepper] is a popular pulse legume component of intercropping farming systems. Often, however, potential production is compromised, particularly in high fertiliser input systems, because blackgram competes with the non-legume component of the system for nitrogen in the soil. In order to identify lines of blackgram that could obtain the majority of their nitrogen requirements from symbiotic fixation of atmospheric nitrogen rather than from uptake of soil nitrogen, 50 genotypes were screened for tolerance to (applied) nitrogen in soil. The parameters used to appraise tolerance were extent of root nodulation, the amount of nitrogen fixed, nitrate reductase activity in roots and nodules, and nitrite content of roots and nodules. There were 2 nitrogen treatments applied as urea, viz. 40 (N40) and 120 (N120) kg N per ha. There were 3 genotypes whose nitrogen-fixing effectiveness was apparently unimpaired by applications of nitrogen to the soil. Genotype NC-59308 nodulated and fixed atmospheric nitrogen satisfactorily at both the lower and higher levels of applied nitrogen. At N40, genotypes EC-48215 and PLU-726 formed a great abundance of large nodules effective in nitrogen fixation; even at N120, both lines had better symbioses than the majority of the 50 blackgram lines originally screened. These 3 genotypes are deemed worthy of further examination for their suitability for intercropping systems. How this might be done is discussed.

Nitrogen Nutrition of Cowpea (Vigna unguiculata)

1977 ◽  
Vol 13 (3) ◽  
pp. 241-252 ◽  
Author(s):  
P. J. Dart ◽  
P. A. Huxley ◽  
A. R. J. Eaglesham ◽  
F. R. Minchin ◽  
R. J. Summerfield ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Vigna Unguiculata ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogen Nutrition ◽  
Combined Nitrogen ◽  
Nitrogen Treatments ◽  
Seed Yields ◽  
Applied Nitrogen

SUMMARYAverage seed yields of effectively nodulated cowpea plants were 38% greater than those of non-nodulated plants when both received applied nitrogen at concentrations ranging from 60 to 240 ppm during one of three periods: emergence to first flower, first flower to mid pod-fill, or mid pod-fill to maturity. Nodulation increased seed yields by 45% when plants received a ‘basal’ level of 30 ppm N throughout growth. None of the combined nitrogen treatments could compensate non-nodulated plants for the loss of symbiotic nitrogen fixation. Non-nodulated plants relying on applied N branched less, produced fewer peduncles and set fewer pods on each peduncle than nodulated plants.

Phenotypic reversion of nitrogenase in pleiotropic mutants of Rhizobium meliloti

1979 ◽  
Vol 25 (3) ◽  
pp. 298-301 ◽  
Author(s):  
Ilona Barabás ◽  
Tibor Sik
Keyword(s):  
Amino Acids ◽  
Nitrogen Fixation ◽  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Symbiotic Nitrogen Fixation ◽  
Rhizobium Meliloti ◽  
Nitrogenase Activity ◽  
Reductase Activity ◽  
Amino Acid Utilization ◽  
Phenotypic Reversion

In two out of three pleiotropic mutants of Rhizobium meliloti, defective in nitrate reductase induced by amino acid utilization in vegetative bacteria and in symbiotic nitrogen fixation, nitrogenase activity could be restored completely by purines and partially by the amino acids L-glutamate, L-aspartate, L-glutamine, and L-asparagine. The compounds restoring effectiveness in nitrogen fixation did not restore nitrate reductase activity in vegetative bacteria. The restoration of effectiveness supports our earlier conclusion that the mutation is not in the structural gene for a suggested common subunit of nitrogenase and nitrate reductase.

The cobalt requirement of subterranean clover in the field

1963 ◽  
Vol 14 (1) ◽  
pp. 39 ◽  
Author(s):  
PG Ozanne ◽  
EAN Greenwood ◽  
TC Shaw
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogen Content ◽  
Symbiotic Nitrogen Fixation ◽  
Subterranean Clover ◽  
Applied Nitrogen

Yield increases of 30% were obtained on two subterranean clover pastures in response to dressings of 2 and 10 oz CoSO4.7H2O per acre. A dressing of salts containing chromium, nickel, vanadium, tungsten, aluminium, and iodine had no effect. Applications of cobalt increased the nitrogen content of the clover in all cases. No response to cobalt was obtained in the presence of adequate applied nitrogen. Clover growth was sharply reduced when cobalt contents fell below 0.04 p.p.m. The unfertilized soils on which the experiments were located contained only 0.022 and 0.019 p.p.m. cobalt in the 0–4 in. layer. Applied cobalt was not leached downward but remained in the surface 4 in. However, less than 0.5% of the applied cobalt was taken up by the pasture. To obtain a response to applied cobalt it appears necessary for legumes to be growing in soil containing Rhizobia capable of symbiotic nitrogen fixation; but the soil must also be very low in available cobalt and nitrogen.

scholarly journals MtMOT1.2 is responsible for molybdate supply toMedicago truncatulanodules

2018 ◽  
Author(s):  
Patricia Gil-Díez ◽  
Manuel Tejada-Jiménez ◽  
Javier León-Mediavilla ◽  
Jiangqi Wen ◽  
Kirankumar S. Mysore ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Reductase Activity ◽  
Root Nodules ◽  
Loss Of Function ◽  
Intracellular Membrane ◽  
Wild Type ◽  
Endodermal Cells ◽  
Iron Molybdenum Cofactor

ABSTRACTSymbiotic nitrogen fixation in legume root nodules requires a steady supply of molybdenum for synthesis of the iron-molybdenum cofactor of nitrogenase. This nutrient has to be provided by the host plant from the soil, crossing several symplastically disconnected compartments through molybdate transporters, including members of the MOT1 family. MtMOT1.2 is aMedicago truncatulaMOT1 family member located in the endodermal cells in roots and nodules. Immunolocalization of a tagged MtMOT1.2 indicates that it is associated to the plasma membrane and to intracellular membrane systems, where it would be transporting molybdate towards the cytosol, as indicated in yeast transport assays. A loss-of-functionmot1.2-1mutant showed reduced growth compared to wild-type plants when nitrogen fixation was required, but not when nitrogen was provided as nitrate. While no effect on molybdenum-dependent nitrate reductase activity was observed, nitrogenase activity was severely affected, explaining the observed difference of growth depending on nitrogen source. This phenotype was the result of molybdate not reaching the nitrogen-fixing nodules, since genetic complementation with a wild-typeMtMOT1.2gene or molybdate-fortification of the nutrient solution, both restored wild-type levels of growth and nitrogenase activity. These results support a model in which MtMOT1.2 would mediate molybdate delivery by the vasculature into the nodules.

Lack of the Flavin-Containing Monooxygenase FmoA Partially Impairs the Symbiotic Interaction of Mesorhizobium Huakuii with Astragalus Sinicus

2020 ◽  
Author(s):  
Hetao Wu ◽  
Qian Zou ◽  
Sha Luo ◽  
Donglan He ◽  
Xiaohua Li ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Target Genes ◽  
Symbiotic Nitrogen Fixation ◽  
Reductase Activity ◽  
Cumene Hydroperoxide ◽  
Nodule Development ◽  
Astragalus Sinicus ◽  
Symbiotic Interaction ◽  
Real Time Quantitative Pcr ◽  
Mesorhizobium Huakuii

Abstract Background: Flavin-containing monooxygenases (FMOs) catalyze the NADPH-dependent N- or S- oxygenation of numerous foreign chemicals, and thus may mediate interactions between microorganisms and their chemical environment. The aim of this study was to investigate the role of FMO in symbiotic nitrogen fixation of Mesorhizobium huakuii and its host plant Astragalus sinicus.Results: A mutation in M. huakuii fmoA gene was generated by homologous recombination. The fmoA mutant grew more slowly than its parental strain, and displayed decreased antioxidative capacity under higher concentration of H2O2 and cumene hydroperoxide (CUOOH), indicating that FmoA plays an important role in response to the peroxides. The fmoA mutant strain displayed no difference of peroxidase activity and glutathione reductase activity, but significantly lower level of glutathione and hydrogen peroxide content than the wild type. Real-time quantitative PCR showed that the fmoA gene expression is significantly up-regulated in three different stages of nodule development. The fmoA mutant was severely impaired in its rhizosphere colonization, and its symbiotic properties in Astragalus sinicus were drastically affected. Transcriptomes in root-nodule bacteroids were analyzed and compared. A total of 1233 genes were differentially expressed, of which 560 were up-regulated and 673 were down-regulated in HKfmoA bacteroids compared with that in 7653R bacteroids. The transcriptomic data allowed us to determine additional target genes, whose differential expression was able to explain the observed the changes of symbiotic phenotype in the mutant-infected nodules.Conclusions: The fmoA gene is essential for antioxidant capacity and symbiotic nitrogen fixation. Furthermore, RNA-Seq based global transcriptomic analysis provided a comprehensive view of M. huakuii fmoA gene involved in nodule senescence and symbiotic nitrogen fixation.

scholarly journals Generation of Bradyrhizobium japonicum Mutants with Increased N2O Reductase Activity by Selection after Introduction of a Mutated dnaQ Gene

2008 ◽  
Vol 74 (23) ◽  
pp. 7258-7264 ◽  
Author(s):  
Manabu Itakura ◽  
Kazufumi Tabata ◽  
Shima Eda ◽  
Hisayuki Mitsui ◽  
Kiriko Murakami ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Bradyrhizobium Japonicum ◽  
Symbiotic Nitrogen Fixation ◽  
Enrichment Culture ◽  
Reductase Activity ◽  
Wild Type ◽  
Epsilon Subunit ◽  
Bacterial Mutants ◽  
N2o Reductase ◽  
Type Strains

ABSTRACT We obtained two beneficial mutants of Bradyrhizobium japonicum USDA110 with increased nitrous oxide (N2O) reductase (N2OR) activity by introducing a plasmid containing a mutated B. japonicum dnaQ gene (pKQ2) and performing enrichment culture under selection pressure for N2O respiration. Mutation of dnaQ, which encodes the epsilon subunit of DNA polymerase III, gives a strong mutator phenotype in Escherichia coli. pKQ2 introduction into B. japonicum USDA110 increased the frequency of occurrence of colonies spontaneously resistant to kanamycin. A series of repeated cultivations of USDA110 with and without pKQ2 was conducted in anaerobic conditions under 5% (vol/vol) or 20% (vol/vol) N2O atmosphere. At the 10th cultivation cycle, cell populations of USDA110(pKQ2) showed higher N2OR activity than the wild-type strains. Four bacterial mutants lacking pKQ2 obtained by plant passage showed 7 to 12 times the N2OR activity of the wild-type USDA110. Although two mutants had a weak or null fix phenotype for symbiotic nitrogen fixation, the remaining two (5M09 and 5M14) had the same symbiotic nitrogen fixation ability and heterotrophic growth in culture as wild-type USDA110.

Nitrogen Nutrition of Cowpea (Vigna unguiculata). I. Effects of Applied Nitrogen and Symbiotic Nitrogen Fixation on Growth and Seed Yield

1977 ◽  
Vol 13 (2) ◽  
pp. 129-142 ◽  
Author(s):  
R. J. Summerfield ◽  
P. J. Dart ◽  
P. A. Huxley ◽  
A. R. J. Eaglesham ◽  
F. R. Minchin ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Seed Yield ◽  
Vigna Unguiculata ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogen Nutrition ◽  
Seed Yields ◽  
Applied Nitrogen

SUMMARYEffectively nodulated cowpea plants, grown in pots without applied nitrogen, were vegetatively equal to non-nodulated plants supplied with 60 ppm N throughout growth (88 days) and produced significantly greater seed yields. Supplying non-nodulated plants with 120 or 240 ppm N improved seed yields (but not significantly) compared with plants completely dependent on symbiotic fixation. Nodulation promoted branching, and improved pod set and/or retention compared with plants relying on applied N.

scholarly journals Plasmids Related to the Symbiotic Nitrogen Fixation Are Not Only Cooperated Functionally but Also May Have Evolved over a Time Span in Family Rhizobiaceae

2020 ◽  
Vol 12 (11) ◽  
pp. 2002-2014
Author(s):  
Ling-Ling Yang ◽  
Zhao Jiang ◽  
Yan Li ◽  
En-Tao Wang ◽  
Xiao-Yang Zhi
Keyword(s):  
Nitrogen Fixation ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Symbiotic Nitrogen Fixation ◽  
Gene Families ◽  
Time Span ◽  
Soil Conditions ◽  
Gene Gain ◽  
Nitrogen Fixing ◽  
Pan Genome

Abstract Rhizobia are soil bacteria capable of forming symbiotic nitrogen-fixing nodules associated with leguminous plants. In fast-growing legume-nodulating rhizobia, such as the species in the family Rhizobiaceae, the symbiotic plasmid is the main genetic basis for nitrogen-fixing symbiosis, and is susceptible to horizontal gene transfer. To further understand the symbioses evolution in Rhizobiaceae, we analyzed the pan-genome of this family based on 92 genomes of type/reference strains and reconstructed its phylogeny using a phylogenomics approach. Intriguingly, although the genetic expansion that occurred in chromosomal regions was the main reason for the high proportion of low-frequency flexible gene families in the pan-genome, gene gain events associated with accessory plasmids introduced more genes into the genomes of nitrogen-fixing species. For symbiotic plasmids, although horizontal gene transfer frequently occurred, transfer may be impeded by, such as, the host’s physical isolation and soil conditions, even among phylogenetically close species. During coevolution with leguminous hosts, the plasmid system, including accessory and symbiotic plasmids, may have evolved over a time span, and provided rhizobial species with the ability to adapt to various environmental conditions and helped them achieve nitrogen fixation. These findings provide new insights into the phylogeny of Rhizobiaceae and advance our understanding of the evolution of symbiotic nitrogen fixation.

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