Symbiotic Properties of Sinorhizobium meliloti and Ethylene Production by Alfalfa Plants at the Early Stages of the Symbiosis Formation under Different Water Supply and Seed Treatment by Lectin

2021 ◽  
Vol 83 (1) ◽  
pp. 32-38
Author(s):  
L.M. Mykhalkiv ◽  
◽  
S.Ya. Kots ◽  
A.V. Zhemojda ◽  
T.A. Kots ◽  
...  
Keyword(s):  
Water Supply ◽  
Ethylene Production ◽  
Sinorhizobium Meliloti ◽  
Nitrogenase Activity ◽  
Negative Regulator ◽  
Stress Factors ◽  
Nitrogen Fixing ◽  
Early Stages ◽  
Symbiotic Properties ◽  
Bacteria Culture

The symbiotic properties of bacteria significantly influence on the effectiveness of symbiosis and the yield capacity of plants. Therefore, it is important and relevant to study the features of micro- and macrosymbionts interactions, in particular under stressful conditions, and to find ways to improve the productivity of symbiotic systems. Aim. The investigation of the nodulation and nitrogen-fixing activities of Sinorhizobium meliloti as well as the ethylene production by alfalfa plants at the early stages of the formation of symbiotic system under conditions of both optimal and insufficient water supply and the pre-sowing treatment of seeds by lectin. Methods. Microbiological (cultivation of bacteria culture, seed inoculation), physiological (pot experiment), biochemical (nitrogenase activity and ethylene production determination). Results. It was observed a decrease of the nodulation activity of Sinorhizobium meliloti under drought as well as under lectin application, which was accompanied by an increase in the amount of produced by macrosymbiont ethylene at the early stages of the symbiosis formation. At the same time, the nitrogen fixing activity was inhibited at the insufficient water supply only. The use of lectin promoted the symbiotic apparatus functioning under optimal and insufficient water supply. After renewal of irrigation an increase of the nodule weight and nitrogen fixing activity as well as the aboveground mass of alfalfa plants were noted under lectin treatment. Conclusions. It was identified the role of ethylene as a negative regulator of the nodulation processes at pre-sowing treatment of alfalfa seeds with lectin. The formation of the effective nitrogen-fixing system capable of full recovery after drought under lectin application confirms the prospects for further research in the use of lectins to create optimal conditions for the realization of the symbiotic potential of rhizobia and to increase the symbiotic systemˊ resistance to the action of stress factors.

Investigations of nitrogenase activity in rheotrophic peat

1976 ◽  
Vol 22 (10) ◽  
pp. 1561-1566 ◽  
Author(s):  
George John Waughman
Keyword(s):  
Ethylene Production ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Anaerobic Bacteria ◽  
Organic Soils ◽  
Nitrogen Fixing ◽  
Anaerobic Conditions ◽  
Time Courses ◽  
Aerobic And Anaerobic ◽  
Stimulation Of

Acetylene reduction by the peat microflora was unaffected by light, but was sensitive to temperature, with an optimum of about 30 °C. The nitrogenase was inactivated by exposure to temperatures above about 35 °C. Activity occurred in completely anaerobic conditions; the rate of ethylene production was of the order of 0.5 nmol C2H4 ml−1h−1. Experiments with time courses indicated that exposure to oxygen caused an initial inhibition of activity followed by a period in which ethylene production was stimulated to rates much higher than in the anaerobic tests; both the inhibition and stimulation appeared to be related to the level of oxygenation. It is suggested that these results could be explained by the existence of nitrogen-fixing associations of aerobic and anaerobic bacteria in the peat. The stimulation of activity caused by exposure to air indicates that care must be taken when interpreting results of the assay obtained from waterlogged organic soils.

scholarly journals LECTIN ACTIVITY IN PLANT ORGANS AT SYMBIOSIS FORMATION of ALFALFA WITH SINORHIZOBIUM MELILOTI UNDER DIFFERENT WATER CONDITIONS

2013 ◽  
Vol 17 ◽  
pp. 21-30
Author(s):  
L.M. Mykhalkiv
Keyword(s):  
Water Supply ◽  
Plant Development ◽  
Sinorhizobium Meliloti ◽  
Lectin Activity ◽  
Plant Organs ◽  
Active Strain ◽  
Early Stages ◽  
Supply Effect ◽  
Water Conditions

The paper covers study of insufficient water supply effect on lectin activity in different organs of alfalfa plants inoculated with Sinorhizobium meliloti 441 (active strain) and SHM1-48 (inactive strain) during the early stages of symbiosis formation and its active functioning. The correlations between the changes of lectin activity in alfalfa plants influenced by different water supply and strain characteristics, extent of plant development and stage of symbiosis formation.

scholarly journals Rhizobium tropici Genes Involved in Free-Living Salt Tolerance are Required for the Establishment of Efficient Nitrogen-Fixing Symbiosis with Phaseolus vulgaris

2002 ◽  
Vol 15 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Joaquina Nogales ◽  
Rosario Campos ◽  
Hanaa BenAbdelkhalek ◽  
José Olivares ◽  
Carmen Lluch ◽  
...  
Keyword(s):  
Salt Tolerance ◽  
Phaseolus Vulgaris ◽  
Environmental Changes ◽  
Nitrogenase Activity ◽  
Regulation Of Gene Expression ◽  
Elongation Factor ◽  
Regulatory System ◽  
Trna Synthetase ◽  
Nitrogen Fixing ◽  
Rhizobium Tropici

Characterization of nine transposon-induced mutants of Rhizobium tropici with decreased salt tolerance (DST) allowed the identification of eight gene loci required for adaptation to high external NaCl. Most of the genes also were involved in adaptation to hyperosmotic media and were required to overcome the toxicity of LiCl. According to their possible functions, genes identified could be classified into three groups. The first group included two genes involved in regulation of gene expression, such as ntrY, the sensor element of the bacterial ntrY/ntrX two-component regulatory system involved in regulation of nitrogen metabolism, and greA, which encodes a transcription elongation factor. The second group included genes related to synthesis, assembly, or maturation of proteins, such as alaS coding for alanine-tRNA synthetase, dnaJ, which encodes a molecular chaperone, and a nifS homolog probably encoding a cysteine desulfurase involved in the maturation of Fe-S proteins. Genes related with cellular build-up and maintenance were in the third group, such as a noeJ-homolog, encoding a mannose-1-phosphate guanylyltransferase likely involved in lipopolysaccharide biosynthesis, and kup, specifying an inner-membrane protein involved in potassium uptake. Another gene was identified that had no homology to known genes but that could be conserved in other rhizobia. When inoculated on Phaseolus vulgaris growing under nonsaline conditions, all DST mutants displayed severe symbiotic defects: ntrY and noeJ mutants were impaired in nodulation, and the remaining mutants formed symbiosis with very reduced nitrogenase activity. The results suggest that bacterial ability to adapt to hyper-osmotic and salt stress is important for the bacteroid nitrogen-fixing function inside the legume nodule and provide genetic evidence supporting the suggestion that rhizobia face severe environmental changes after their release into plant cells.

New marine nitrogen-fixing bacteria isolated from an eelgrass (Zostera marina) bed

1988 ◽  
Vol 34 (7) ◽  
pp. 886-890 ◽  
Author(s):  
Wung Yang Shieh ◽  
Usio Simidu ◽  
Yoshiharu Maruyama
Keyword(s):  
Zostera Marina ◽  
Nitrogenase Activity ◽  
Molecular Nitrogen ◽  
Exponential Growth Phase ◽  
Nitrogen Fixing ◽  
Low Oxygen ◽  
Nitrogen Fixing Bacteria ◽  
Nitrogen Fixation Activity ◽  
The Family ◽  
Ph Decrease

Four strains of marine nitrogen-fixing bacteria were isolated from the roots of eelgrass (Zostera marina) and from sediments in an eelgrass bed in Aburatsubo Inlet, Kanagawa Prefecture, Japan. Significant levels of nitrogenase activity were detected in all four strains after a few hours of incubation under anaerobic conditions. Nitrogenase activity in all cases was Na+ dependent. These strains grew anaerobically or under conditions of low oxygen, using molecular nitrogen as the sole nitrogen source. Bacterial growth in liquid nitrogen-free medium was accompanied by a marked pH decrease during the exponential growth phase. Neither yeast extract nor vitamins were required for the nitrogen fixation activity of these strains. Taxonomically, all strains were facultatively anaerobic, Gram-negative rods. They were motile in liquid medium by means of a single polar flagellum and required NaCl for their growth. These characteristics, as well as the guanine + cytosine content of their DNA (43.5 – 44.8 mol%), placed them in the family Vibrionaceae. These strains, however, could not be identified to the genus level because they were distinct from the two halophilic genera Vibrio and Photobacterium of the family Vibrionaceae by a variety of characteristics.

Nitrogen fixation (acetylene reduction) by Klebsiella pneumoniae in association with 'Park' Kentucky bluegrass (Poa pratensis L.)

1981 ◽  
Vol 27 (1) ◽  
pp. 52-56 ◽  
Author(s):  
L. V. Wood ◽  
R. V. Klucas ◽  
R. C. Shearman
Keyword(s):  
Nitrogen Fixation ◽  
Klebsiella Pneumoniae ◽  
Ethylene Production ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Surface Sterilization ◽  
Reducing Activity ◽  
Acetylene Reducing Activity

Turfs of 'Park' Kentucky bluegrass reestablished in the greenhouse and inoculated with Klebsiella pneumoniae (W6) showed significantly increased nitrogen fixation (acetylene reduction) compared with control turfs. Mean ethylene production rates per pot were 368 nmol h−1 for K. pneumoniae treated turfs, 55 nmol h−1 for heat-killed K. pneumoniae treated turfs, and 44 nmol h−1 for untreated turfs. Calculated lag periods before activity was observed were generally very short (less than 1 h).When 'Park' Kentucky bluegrass was grown from seed on soil-less medium of Turface, a fired aggregate clay, inoculation with K. pneumoniae (W6) resulted in 9 of 11 turfs showing nitrogenase activity (mean ethylene producion rate per pot was 195 nmol h−1). Only 3 of 11 turfs treated with heat-killed K. pneumoniae showed any activity and their mean rate of ethylene production (40 nmol h−1 per pot) was significantly lower than that for turfs treated with K. pneumoniae.Using the 'Park'–Turface soil-less model system it was shown that acetylene reducing activity was (i) root associated, (ii) generally highest at a depth of 1–4 cm below the surface, (iii) enhanced by washing excised roots, and (iv) inhibited by surface sterilization of excised roots. Klebsiella pneumoniae was recovered from Turface and roots showing acetylene reducing activity.

Nitrogen fixation

1976 ◽  
Vol 274 (934) ◽  
pp. 341-358 ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Metabolic Regulation ◽  
Higher Plants ◽  
Focal Point ◽  
Nitrogenase Activity ◽  
Nitrogen Fixing ◽  
Blue Green Algae ◽  
International Biological Programme ◽  
The 1960S ◽  
Biological Programme

The International Biological Programme served as a focal point for studies on biological nitrogen fixation during the 1960s. The introduction of the acetylene reduction technique for measuring nitrogenase activity in the field led to estimates becoming available of the contribution of lichens, blue-green algae, nodulated non-legumes and bacterial-grass associations, as well as of legumes. Other studies carried out on the physiology and biochemistry of the process led to the eventual purification and characterization of the nitrogenase enzyme. These studies, collectively, provided the springboard for current work, so essential in view of the present energy crisis, on how to increase the use and efficiency of nitrogen-fixing plants, on the metabolic regulation of the nitrogenase enzyme and on the genetics of the nitrogen-fixing process, both in higher plants and in free-living micro-organisms.

Optimal conditions for induction of competence in nitrogen-fixing Azotobacter vinelandii

1982 ◽  
Vol 28 (4) ◽  
pp. 389-397 ◽  
Author(s):  
William J. Page
Keyword(s):  
Dissolved Oxygen ◽  
Sodium Acetate ◽  
Azotobacter Vinelandii ◽  
Nitrogenase Activity ◽  
Cell Mass ◽  
Apparent Competition ◽  
Competence Development ◽  
Optimal Conditions ◽  
Nitrogen Fixing ◽  
Ph Range

Competence development in nitrogen-fixing Azotobacter vinelandii cells was optimal at pH 7.2–7.4 which necessitated additional buffering of the iron-limited nitrogen-free competence medium or the addition of a suitable organic acid salt, e.g., sodium acetate. An autolysin was active in this pH range and competent cells were more susceptible to autolysis than the general cell population. Competence development also required restricted aeration of the culture, and only those cultures that attained zero dissolved oxygen became competent. Restricted aeration served to protect the iron-limited cell nitrogenase from oxygen inactivation thus allowing the culture to reach zero dissolved oxygen. The inclusion of additional sources of reductant, e.g., malate, in buffered competence medium resulted in increased respiration and protection of nitrogenase, increased cell mass, and poly-β-hydroxybutyrate synthesis, but decreased competence. A possible explanation for the apparent competition between competence development and nitrogenase activity is discussed.

scholarly journals Inoculation with Efficient Nitrogen Fixing and Indoleacetic Acid Producing Bacterial Microsymbiont Enhance Tolerance of the Model LegumeMedicago truncatulato Iron Deficiency

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Nadia Kallala ◽  
Wissal M’sehli ◽  
Karima Jelali ◽  
Zribi Kais ◽  
Haythem Mhadhbi
Keyword(s):  
Oxidative Stress ◽  
Iron Deficiency ◽  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Plant Biomass ◽  
High Growth ◽  
Fe Deficiency ◽  
Nitrogen Fixing ◽  
Bacterial Strains ◽  
Negative Effect

The aim of this study was to assess the effect of symbiotic bacteria inoculation on the response ofMedicago truncatulagenotypes to iron deficiency. The present work was conducted on threeMedicago truncatulagenotypes: A17, TN8.20, and TN1.11. Three treatments were performed: control (C), direct Fe deficiency (DD), and induced Fe deficiency by bicarbonate (ID). Plants were nitrogen-fertilized (T) or inoculated with two bacterial strains:Sinorhizobium melilotiTII7 andSinorhizobium medicaeSII4. Biometric, physiological, and biochemical parameters were analyzed. Iron deficiency had a significant lowering effect on plant biomass and chlorophyll content in allMedicago truncatulagenotypes. TN1.11 showed the highest lipid peroxidation and leakage of electrolyte under iron deficiency conditions, which suggest that TN1.11 was more affected than A17 and TN8.20 by Fe starvation. Iron deficiency affected symbiotic performance indices of allMedicago truncatulagenotypes inoculated with bothSinorhizobiumstrains, mainly nodules number and biomass as well as nitrogen-fixing capacity. Nevertheless, inoculation withSinorhizobiumstrains mitigates the negative effect of Fe deficiency on plant growth and oxidative stress compared to nitrogen-fertilized plants. The highest auxin producing strain, TII7, preserves relatively high growth and root biomass and length when inoculated to TN8.20 and A17. On the other hand, both TII7 and SII4 strains improve the performance of sensitive genotype TN1.11 through reduction of the negative effect of iron deficiency on chlorophyll and plant Fe content. The bacterial inoculation improved Fe-deficient plant response to oxidative stress via the induction of the activities of antioxidant enzymes.

Nitrogen Fixation on the Tropical Volcano, La Soufrière (Guadeloupe): Nitrogen Fixation, Photosynthesis and Respiration During the Prevailing Cloud/Shroud Climate By Stereocaulon Virgatum

1988 ◽  
Vol 20 (1) ◽  
pp. 41-61 ◽  
Author(s):  
R. P. Fritz-Sheridan ◽  
D. S. Coxson
Keyword(s):  
Nitrogen Fixation ◽  
Ethylene Production ◽  
Nitrogenase Activity ◽  
Lava Flows ◽  
The West ◽  
Recovery Pattern ◽  
Light Intensities ◽  
Major Variable ◽  
The Mean ◽  
Photosynthesis And Respiration

AbstractStereocaulon virgatum Ach. has colonized lava flows deposited on the west flank of the volcano La Soufrière. The mean annual rate of acetylene reduction was 43·4 nmol C2H4 gdw−1 h−1 with maximum rates during the prevalent cloud/shroud meteorology of 101 and minimum rates during rare high insolation events of 0·63 nmol gdw−1 h−1. Percentage thallus moisture was the major variable controlling nitrogenase activity. During cloud/shroud conditions the upper 90% of the lichen canopy reduced 85% of the acetylene. Canopy shading reduced intra-canopy temperatures allowing the basal 10% of the canopy to fix nitrogen during insolation shocks. Basal portions of pseudopodetia exhibited reduced rates of ethylene production when exposed to canopy surface light intensities during cloud/shroud conditions. The recovery pattern of nitrogenase following desiccation during an insolation shock is presented. Rates of photosynthesis during cloud/shroud conditions were high, reaching 50% of those attained during saturating light intensities.

scholarly journals Important Late-Stage Symbiotic Role of theSinorhizobium melilotiExopolysaccharide Succinoglycan

2018 ◽  
Vol 200 (13) ◽  
pp. e00665-17 ◽  
Author(s):  
Markus F. F. Arnold ◽  
Jon Penterman ◽  
Mohammed Shabab ◽  
Esther J. Chen ◽  
Graham C. Walker
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Late Stage ◽  
Sinorhizobium Meliloti ◽  
Antimicrobial Action ◽  
Protective Function ◽  
Content Type ◽  
Early Stages ◽  
Symbiotic Interactions ◽  
Legume Symbiosis

ABSTRACTSinorhizobium melilotienters into beneficial symbiotic interactions withMedicagospecies of legumes. Bacterial exopolysaccharides play critical signaling roles in infection thread initiation and growth during the early stages of root nodule formation. After endocytosis ofS. melilotiby plant cells in the developing nodule, plant-derived nodule-specific cysteine-rich (NCR) peptides mediate terminal differentiation of the bacteria into nitrogen-fixing bacteroids. Previous transcriptional studies showed that the intensively studied cationic peptide NCR247 induces expression of theexogenes that encode the proteins required for succinoglycan biosynthesis. In addition, genetic studies have shown that someexomutants exhibit increased sensitivity to the antimicrobial action of NCR247. Therefore, we investigated whether the symbiotically activeS. melilotiexopolysaccharide succinoglycan can protectS. melilotiagainst the antimicrobial activity of NCR247. We discovered that high-molecular-weight forms of succinoglycan have the ability to protectS. melilotifrom the antimicrobial action of the NCR247 peptide but low-molecular-weight forms of wild-type succinoglycan do not. The protective function of high-molecular-weight succinoglycan occurs via direct molecular interactions between anionic succinoglycan and the cationic NCR247 peptide, but this interaction is not chiral. Taken together, our observations suggest thatS. melilotiexopolysaccharides not only may be critical during early stages of nodule invasion but also are upregulated at a late stage of symbiosis to protect bacteria against the bactericidal action of cationic NCR peptides. Our findings represent an important step forward in fully understanding the complete set of exopolysaccharide functions during legume symbiosis.IMPORTANCESymbiotic interactions between rhizobia and legumes are economically important for global food production. The legume symbiosis also is a major part of the global nitrogen cycle and is an ideal model system to study host-microbe interactions. Signaling between legumes and rhizobia is essential to establish symbiosis, and understanding these signals is a major goal in the field. Exopolysaccharides are important in the symbiotic context because they are essential signaling molecules during early-stage symbiosis. In this study, we provide evidence suggesting that theSinorhizobium melilotiexopolysaccharide succinoglycan also protects the bacteria against the antimicrobial action of essential late-stage symbiosis plant peptides.

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