scholarly journals Cellular Location and Concentration of Leghaemoglobin in Soybean Root Nodules

1973 ◽  
Vol 26 (4) ◽  
pp. 741 ◽  
Author(s):  
FJ Bergersen ◽  
DJ Goodchild
Keyword(s):  
Root Nodule ◽  
Root Nodules ◽  
Fresh Tissue ◽  
Cellular Location ◽  
Soybean Root ◽  
Tissue Sections

The reaction of leghaemoglobin (Lb) with oxidized 3,3'-diaminobenzidine has been used to demonstrate the localization of this haemoprotein within the membrane envelopes surrounding the bacteroids in soybean root nodule cells. In fresh tissue sections mounted in a modified Honda medium, the reagent stained the envelope contents a brick-red colour.

Studies on possible routes of ammonium assimilation in soybean root nodule bacteroids

1973 ◽  
Vol 19 (12) ◽  
pp. 1493-1499 ◽  
Author(s):  
Stanley D. Dunn ◽  
Robert V. Klucas
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Assimilation ◽  
Reductive Amination ◽  
Root Nodule ◽  
Root Nodules ◽  
Ammonium Assimilation ◽  
Kinetic Properties ◽  
Transferase Activity ◽  
Soybean Root

Glutamine amide–2-oxoglutarate aminotransferase NAD+ oxidoreductase (GOGAT), glutamine synthetase (GS), glutamate dehydrogenase (GD), and alanine dehydrogenase (AD) were studied in soybean root nodules. GS, GOGAT, and AD were present in bacteroids at levels that could account for ammonium assimilation, but GD activity was quite low. The total activities of GS and GD were higher in the cytosol than in the bacteroids by factors of 20 and 7, respectively, whereas GOGAT was not detected in the cytosol. GS (transferase activity) was inhibited by alanine, CTP, glycine, and tryptophan at 5 mM but was relatively unaffected by asparagine, aspartic acid, CMP, glucosamine, and histidine at 5 mM. GOGAT activity was unaffected by ATP, ADP, 8-hydroxyquinoline, and 1,10-phenanthroline but was inhibited by EDTA, citrate, and parachloromercuribenzoate. GOGAT activity (reductive amination) was also inhibited 97% by preincubation with 10−4 M azaserine for 30 min but GD activity was inhibited only 13%. The apparent Km values for NH4+ by AD was 7.4 × 10−3 M and by GD was 7.3 × 10−2 M while for glutamine by GOGAT it was 9.3 × 10−5 M. Activities and kinetic properties for these enzymes may suggest potential routes of nitrogen assimilation in vivo.

scholarly journals Soybean Root Nodule and Rhizosphere Microbiome: Distribution of Rhizobial and Nonrhizobial Endophytes

2021 ◽  
Vol 87 (10) ◽  
Author(s):  
Parris Mayhood ◽  
Babur S. Mirza
Keyword(s):  
Plant Growth ◽  
Random Process ◽  
Host Plant ◽  
Soil Nitrogen ◽  
Root Nodule ◽  
Root Nodules ◽  
Bacterial Endophytes ◽  
Content Type ◽  
Soybean Root ◽  
Selection Of

ABSTRACT Soybean root nodules are known to contain a high diversity of both rhizobial endophytes and nonrhizobial endophytes (NREs). Nevertheless, the variation of these bacteria among different root nodules within single plants has not been reported. So far, it is unclear whether the selection of NREs among different root nodules within single plants is a random process or is strictly controlled by the host plant to favor a few specific NREs based on their beneficial influence on plant growth. As well, it is also unknown if the relative frequency of NREs within different root nodules is consistent or if it varies based on the location or size of a root nodule. We assessed the microbiomes of 193 individual soybean root nodules from nine plants using high-throughput DNA sequencing. Bradyrhizobium japonicum strains occurred in high abundance in all root nodules despite the presence of other soybean-compatible rhizobia, such as Ensifer, Mesorhizobium, and other species of Bradyrhizobium in soil. Nitrobacter and Tardiphaga were the two nonrhizobial genera that were uniformly detected within almost all root nodules, though they were in low abundance. DNA sequences related to other NREs that have frequently been reported, such as Bacillus, Pseudomonas, Flavobacterium, and Variovorax species, were detected in a few nodules. Unlike for Bradyrhizobium, the low abundance and inconsistent occurrence of previously reported NREs among different root nodules within single plants suggest that these microbes are not preferentially selected as endophytes by host plants and most likely play a limited part in plant growth as endophytes. IMPORTANCE Soybean (Glycine max L.) is a valuable food crop that also contributes significantly to soil nitrogen by developing a symbiotic association with nitrogen-fixing rhizobia. Bacterial endophytes (both rhizobial and nonrhizobial) are considered critical for the growth and resilience of the legume host. In the past, several studies have suggested that the selection of bacterial endophytes within root nodules can be influenced by factors such as soil pH, nutrient availability, host plant genotype, and bacterial diversity in soil. However, the influence of size or location of root nodules on the selection of bacterial endophytes within soybean roots is unknown. It is also unclear whether the selection of nonrhizobial endophytes within different root nodules of a single plant is a random process or is strictly regulated by the host. This information can be useful in identifying potential bacterial species for developing bioinoculants that can enhance plant growth and soil nitrogen.

scholarly journals Aeration Pathways in Soybean Root Nodules

1973 ◽  
Vol 26 (4) ◽  
pp. 729 ◽  
Author(s):  
FJ Bergersen ◽  
DJ Goodchild
Keyword(s):  
Electron Microscopy ◽  
Root Nodule ◽  
Root Nodules ◽  
Light And Electron Microscopy ◽  
Intercellular Spaces ◽  
Soybean Root

Soybean root nodule tissues contain many interconnected gas-filled intercellular spaces. They have been studied, in fresh and embedded tissue during the development and functional life of the nodules, by light and electron microscopy.

scholarly journals Equilibria and Kinetics of Ligand Binding by Leghemoglobin from Soybean Root Nodules

1972 ◽  
Vol 247 (2) ◽  
pp. 521-526
Author(s):  
Takashi Imamura ◽  
Austen Riggs ◽  
Quentin H. Gibson
Keyword(s):  
Ligand Binding ◽  
Root Nodules ◽  
Soybean Root ◽  
Kinetics Of

scholarly journals Aboveground plant-to-plant communication reduces root nodule symbiosis and soil nutrient concentrations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuta Takahashi ◽  
Kaori Shiojiri ◽  
Akira Yamawo
Keyword(s):  
Root Nodule ◽  
Total Phenolics ◽  
Root Nodules ◽  
Soil Nutrient ◽  
Chemical Defenses ◽  
Nutrient Concentrations ◽  
Soil C ◽  
Plant Communication ◽  
Root Nodule Symbiosis ◽  
Nodule Symbiosis

AbstractAboveground communication between plants is well known to change defense traits in leaves, but its effects on belowground plant traits and soil characteristics have not been elucidated. We hypothesized that aboveground plant-to-plant communication reduces root nodule symbiosis via induction of bactericidal chemical defense substances and changes the soil nutrient environment. Soybean plants were exposed to the volatile organic compounds (VOCs) from damaged shoots of Solidago canadensis var. scabra, and leaf defense traits (total phenolics, saponins), root saponins, and root nodule symbiosis traits (number and biomass of root nodules) were measured. Soil C/N ratios and mineral concentrations were also measured to estimate the effects of resource uptake by the plants. We found that total phenolics were not affected. However, plants that received VOCs had higher saponin concentrations in both leaves and roots, and fewer root nodules than untreated plants. Although the concentrations of soil minerals did not differ between treatments, soil C/N ratio was significantly higher in the soil of communicated plants. Thus, the aboveground plant-to-plant communication led to reductions in root nodule symbiosis and soil nutrient concentrations. Our results suggest that there are broader effects of induced chemical defenses in aboveground plant organs upon belowground microbial interactions and soil nutrients, and emphasize that plant response based on plant-to-plant communications are a bridge between above- and below-ground ecosystems.

scholarly journals Coalescence of rhizobial communities in soil interacts with fertilization and determines the assembly of rhizobia in root nodules

2020 ◽  
Author(s):  
Josep Ramoneda ◽  
Johannes Le Roux ◽  
Stefanie Stadelmann ◽  
Emmanuel Frossard ◽  
Beat Frey ◽  
...  
Keyword(s):  
Microbial Community ◽  
Soil Microbial Community ◽  
Root Nodule ◽  
Root Nodules ◽  
Arable Land ◽  
Soil Microbial ◽  
Soil Mixing ◽  
Environmental Setting ◽  
Widespread Phenomenon ◽  
The Individual

AbstractSoil microbial community coalescence, whereby entire microbial communities mix and compete in a new environmental setting, is a widespread phenomenon whose applicability for targeted root microbiome assembly has not been studied. Using a legume shrub adapted to nutrient poor soil, we tested for the first time how the assembly of communities of rhizobial root nodule symbionts is affected by the interaction of coalescence and fertilization. Seedlings of the rooibos [Aspalathus linearis (Burm.f.) Dahlg.], were raised in pairwise mixtures of soil from cultivated and uncultivated land of five farms, as well as the individual mixture components. A fragment of the symbiosis maker gene, nodA, was sequenced to characterize the taxonomic turnover of the rhizobia associated with all root nodules at the age of eight month. Soil mixing promoted taxonomic turnover in the rhizobial communities, while fertilization amplified such turnover by increasing the number of rhizobia that became more abundant after soil mixing. Soil mixing and fertilization had a synergistic effect on the abundance of a particular taxon, which was rare in the component soils but became highly abundant in fertilized plants raised in soil mixtures. These findings provide the first evidence that fertilizer addition can interact with soil microbial community coalescence, probably through increasing the chances for rare strains to prioritize root nodule colonization. The combination of soil mixing and fertilizer addition may be a still unexplored measure to (re)introduce root microbial mutualists in arable land.

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