Confirmation of the infectivity of a free-living actinomycete isolated from Comptonia peregrina root nodules by immunological and ultrastructural studies

1978 ◽  
Vol 56 (21) ◽  
pp. 2621-2635 ◽  
Author(s):  
Maurice Lalonde
Keyword(s):  
Nitrogen Fixation ◽  
Pure Culture ◽  
Root Nodules ◽  
Free Living ◽  
Ultrastructural Studies ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity ◽  
Membrane Envelope ◽  
Freeze Etching

The inoculation of the host plant Comptonia peregrina (L.) Coult. (Myrica asplenifolia L.) by a pure culture of a free-living actinomycete, isolated from Comptonia root nodules by Callaham et al. (1978, Science, 199: 899–902), was successful. Short-term and long-term nodulation tests confirmed the infectivity of the Comptonia isolate. Acetylene reduction assays of the nodules induced by this prokaryote isolate demonstrated nitrogen fixation activity. This nitrogen fixation activity was able to sustain a prolific growth of the nodulated host plants growing in a N-free substrate. Indirect immufluorescence reactions, using specific gamma globulin against the actinomycetal isolate of the Comptonia root nodule, demonstrated the identity of this actinomycete in these in vitro produced Comptonia root nodules. Ultrastructure of the Comptonia isolate, developing as a free-living or endophytic actinomycete, was observed by light microscopy, freeze etching, and transmission electron microscopy. The free-living filamentous and sporulating isolate produced typical hyphae and vesicles when growing as an endophyte in the Comptonia nodule. These endophytic hyphae and vesicles were always encapsulated by a polysaccharide material which was surrounded by a host membrane envelope. A polysaccharide capsule was not demonstrated on the free-living Comptonia isolate. The endophytic vesicles were club shaped and highly septate. Such vesicles were never produced by the free-living isolate growing in an artificial medium. The Comptonia isolate is a spore former in pure culture and was able to sporulate in basal tissues of 5-month-old Comptonia nodules.

scholarly journals The reaction of self-fertile alfalfa lines to inoculation with nodule bacteria

2020 ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Sinorhizobium Meliloti ◽  
Root Nodules ◽  
Growing Season ◽  
Dry Mass ◽  
Nodule Bacteria ◽  
Forage Crop ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity ◽  
Different Strains

Under the conditions of a model pot experiments, the reaction of the self-fertile lines of alfalfa Kishvardy 46, Kishvardy 27, Vertus and Ziguen to inoculation with nodule bacteria Sinorhizobium meliloti AC48 and AC88 was studied. As a result of studies, it was found that the intensity of assimilation of N2 by symbiotic systems created with the participation of various genotypes of alfalfa and active strains of S. meliloti is one of the main factors that affects the vegetative mass yield of this important forage crop. Self-fertile lines of Medicago sativa L. plants, inoculated with different strains of rhizobia were characterized by higher rates of the mass formed on the root nodules, compared to the control plants of the alfalfa variety Yaroslavna. The traditional dynamics of nitrogen-fixation activity of root nodules was maintained in all the symbiotic systems studied by us, with low values in the stems formation stage and intensive growth in the budding and flowering stages. The highest level of nitrogen fixation and vegetative growth of plants (values of plants green and dry mass, roots and root nodules mass) was established by inoculation of alfalfa line Kishvardy 46 with strain S. meliloti AC48. During the growing season the indices of the mass of nodules formed on the roots of these plants were higher by 1.8–2.3 times, the green mass by 1.2–1.6 times and the height of the plants 1.2–1.4 times as compared to the control. In the flowering stages the nitrogen-fixation activity of the symbiotic complex of plants of the Kishvardy line 27 and nodule bacteria S. meliloti AC48 exceeded the values in the symbiotic systems formed with the participation of the same strain and plants of the Ziguen and Vertus lines by 13.0 and 39.4 %. The lowest values of nitrogen fixation activity were observed by inoculation of plants of the Vertus and Ziguen lines with active strains S. meliloti AC48 and AC88 compared to the symbioses formed by the plants of the Kishvardy lines 27 and 46, as well as of the control-variety Yaroslavna with the noted strains. A stimulating effect of inoculation of alfalfa seeds of different genotypes on the growth and development of plants was noted, as evidenced by the positive dynamics of the increase in above-ground mass, the accumulation of dry matter and higher than the control values (indicators) of plant height during the growing season.

scholarly journals Effect of abscisic acid on symbiotic nitrogen fixation activity in the root nodules ofLotus japonicus

2010 ◽  
Vol 5 (4) ◽  
pp. 440-443 ◽  
Author(s):  
Akiyoshi Tominaga ◽  
Maki Nagata ◽  
Koichi Futsuki ◽  
Hidetoshi Abe ◽  
Toshiki Uchiumi ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Abscisic Acid ◽  
Symbiotic Nitrogen Fixation ◽  
Root Nodules ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity

Environmental factors influencing the nitrogen fixation activity of free-living terrestrial cyanobacteria from a high arctic area, Spitsbergen

1999 ◽  
Vol 45 (7) ◽  
pp. 573-581 ◽  
Author(s):  
Turid Liengen
Keyword(s):  
Nitrogen Fixation ◽  
High Arctic ◽  
Nostoc Commune ◽  
Free Living ◽  
Terrestrial Cyanobacteria ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity ◽  
Field Samples ◽  
Anabaena Sp ◽  
Arctic Area

The influence of environmental factors on the nitrogen fixation activity of free-living, terrestrial cyanobacteria from a high arctic area were investigated using experimental manipulations with two different types of field samples, including macroscopic sheets of Nostoc commune and soil samples with a cyanobacterial crust from a Puccinellia salt marsh. In addition, a cultured Anabaena sp. previously isolated from the salt marsh was examined. Nitrogen fixation activity was measured using the acetylene reduction method. The nitrogen fixation mainly took place in the light, but even after 12 h incubation in darkness, low activities were maintained. Phosphorus fertilization stimulated the nitrogen fixation activity, and the highest activities were obtained with about 300 μM phosphate, both in the field samples and the cultured Anabaena sp. Ammonium (28 mM) immediately inhibited the nitrogen fixation activity of the cultured Anabaena sp, whereas 14 mM urea and 540 μM glutamate led to a weaker and slower inhibition of the nitrogen fixation activity, showing that the cultured Anabaena sp. was able to assimilate these combined nitrogen sources. Nitrate did not have any inhibitory effect on nitrogen fixation activity, either in the field samples or in the cultured Anabaena sp. Both the field samples and the cultured Anabaena sp. showed tolerance against sodium chloride concentrations corresponding to the concentration in seawater. The temperature optimum of the nitrogen fixation activity of the cultured Anabaena sp. was about 20°C. Key words: nitrogen fixation, cyanobacteria, Nostoc commune, Anabaena sp., high arctic.

scholarly journals Lon Protease of Azorhizobium caulinodans ORS571 Is Required for Suppression ofrebGene Expression

2012 ◽  
Vol 78 (17) ◽  
pp. 6251-6261 ◽  
Author(s):  
Azusa Nakajima ◽  
Toshihiro Aono ◽  
Shuhei Tsukada ◽  
Lowela Siarot ◽  
Tetsuhiro Ogawa ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Host Cells ◽  
Lon Protease ◽  
Bacterial Cells ◽  
Azorhizobium Caulinodans ◽  
Free Living ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity

ABSTRACTBacterial Lon proteases play important roles in a variety of biological processes in addition to housekeeping functions. In this study, we focused on the Lon protease ofAzorhizobium caulinodans, which can fix nitrogen both during free-living growth and in stem nodules of the legumeSesbania rostrata. The nitrogen fixation activity of anA. caulinodanslonmutant in the free-living state was not significantly different from that of the wild-type strain. However, the stem nodules formed by thelonmutant showed little or no nitrogen fixation activity. By microscopic analyses, two kinds of host cells were observed in the stem nodules formed by thelonmutant. One type has shrunken host cells containing a high density of bacteria, and the other type has oval or elongated host cells containing a low density or no bacteria. This phenotype is similar to apraRmutant highly expressing therebgenes. Quantitative reverse transcription-PCR analyses revealed thatrebgenes were also highly expressed in thelonmutant. Furthermore, alon rebdouble mutant formed stem nodules showing higher nitrogen fixation activity than thelonmutant, and shrunken host cells were not observed in these stem nodules. These results suggest that Lon protease is required to suppress the expression of therebgenes and that high expression ofrebgenes in part causes aberrance in theA. caulinodans-S. rostratasymbiosis. In addition to the suppression ofrebgenes, it was found that Lon protease was involved in the regulation of exopolysaccharide production and autoagglutination of bacterial cells.

scholarly journals Activity of nitrogen fixation and antioxidant enzymes in symbiotic systems Glycine max – Bradyrhizobium japonicum for complex treatment with lectin and fungicides

2018 ◽  
Vol 9 (2) ◽  
pp. 148-155
Author(s):  
S. Y. Kots ◽  
T. P. Mamenko ◽  
A. V. Pavlyshche
Keyword(s):  
Superoxide Dismutase ◽  
Nitrogen Fixation ◽  
Antioxidant Enzymes ◽  
Bradyrhizobium Japonicum ◽  
Root Nodules ◽  
Guaiacol Peroxidase ◽  
Complex Treatment ◽  
Mass Flowering ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity

The dynamics of the nitrogen fixation activity of the root nodules, the growth of the vegetative mass of plants and the change in the activity of antioxidant enzymes (superoxide dismutase, ascorbate and guaiacol peroxidase) in different soybean organs for treatment of seeds by rhizobia incubated with lectin, in combination with fungicides have been studied. The objects of the study were symbiotic systems formed with the participation of soybean (Glycine max (L.) Merr.) Almaz and Bradyrhizobium japonicum (standard strain 634b) incubated with lectin. As disinfectants of soybean seeds, the following preparations with fungicidal activity were used – Maxim XL 035 PS, Fever, Standak Top according to one rate of active substance consumption of each preparation specified by the manufacturer. One part of the seeds treated with fungicides was inoculated with pure culture of suspension of rhizobia for one hour (titre of suspension concentration was 108 cells/ml). Another part of the seeds treated with fungicides was inoculated with rhizobia suspension, which was previously incubated with a solution of commercial lectin soybean at a concentration of 100 μg/ml. The research was conducted in strictly controlled conditions of a model vegetative experiment using microbiological, physiological, biochemical methods, gas chromatography, spectrophotometry. It was found that processing of soybean seeds with fungicides (Fever and Maxim XL) together with rhizobium inoculation contributed to the preservation of the nitrogen fixation activity of the root nodules and the growth of vegetative mass of plants. Under these conditions, the intensification of the activity of superoxide dismutase and ascorbate peroxidase was observed, as well as inhibition of the activity of guaiacol peroxidase in soybean root nodules in the phase of three true leaves and increased activity of all investigated enzymes in the phase of mass flowering. It has been established that the use of complex treatment of seeds by soybean rhizobia incubated with lectin and fungicides leads to an increase in the activity of superoxide dismutase and guaiacol peroxidase in root nodules in the phase of three true leaves and the growth of the activity of ascorbate peroxidase in the phase of mass flowering. At the same time, the inhibition of the growth of vegetative mass of plants and their symbiotic properties occurred, as evidenced by the decrease in the nitrogen fixation activity of the root nodules for the joint treatment of seeds with fungicides and lectin. A specific reaction of investigated enzymes in the roots and leaves of soybean was shown, which was more pronounced in the phase of three true leaves, indicating the development of a typical antioxidant reaction to a complex treatment, as a kind of stress that is leveled to the phase of mass flowering. The degree of reaction of antioxidant enzymes in the studied symbiotic systems Glycine max – Bradyrhizobium japonicum depends on the nature of the active substance fungicides and the manifestation of their joint effect in a complex with rhizobia incubated with lectin.

scholarly journals Transcriptomics differentiate two novel bioactive strains of Paenibacillus sp. isolated from the perennial ryegrass seed microbiome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tongda Li ◽  
Ross Mann ◽  
Jatinder Kaur ◽  
German Spangenberg ◽  
Timothy Sawbridge
Keyword(s):  
Nitrogen Fixation ◽  
Secondary Metabolite ◽  
Perennial Ryegrass ◽  
Fusarium Verticillioides ◽  
In Vitro Assays ◽  
Colletotrichum Graminicola ◽  
Nitrogen Fixation Activity ◽  
Auxin Production ◽  
Paenibacillus Sp

AbstractPaenibacillus species are Gram-positive bacteria that have been isolated from a diverse array of plant species and soils, with some species exhibiting plant growth-promoting (PGP) activities. Here we report two strains (S02 and S25) of a novel Paenibacillus sp. that were isolated from perennial ryegrass (Lolium perenne) seeds. Comparative genomics analyses showed this novel species was closely related to P. polymyxa. Genomic analyses revealed that strains S02 and S25 possess PGP genes associated with biological nitrogen fixation, phosphate solubilisation and assimilation, as well as auxin production and transportation. Moreover, secondary metabolite gene cluster analyses identified 13 clusters that are shared by both strains and three clusters unique to S25. In vitro assays demonstrated strong bioprotection activity against phytopathogens (Colletotrichum graminicola and Fusarium verticillioides), particularly for strain S02. A transcriptomics analysis evaluating nitrogen fixation activity showed both strains carry an expressed nif operon, but strain S02 was more active than strain S25 in nitrogen-free media. Another transcriptomics analysis evaluating the interaction of strains with F. verticillioides showed strain S02 had increased expression of core genes of secondary metabolite clusters (fusaricidin, paenilan, tridecaptin and polymyxin) when F. verticillioides was present and absent, compared to S25. Such bioactivities make strain S02 a promising candidate to be developed as a combined biofertiliser/bioprotectant.

scholarly journals Root Distribution and Nitrogen Fixation Activity of Tropical Forage Legume American Jointvetch (Aeschynomene americanaL.) cv. Glenn under Waterlogging Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Manabu Tobisa ◽  
Masataka Shimojo ◽  
Yasuhisa Masuda
Keyword(s):  
Nitrogen Fixation ◽  
Root Distribution ◽  
Water Surface ◽  
Nitrogenase Activity ◽  
Soil Surface ◽  
Nodule Formation ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity ◽  
Net Assimilation ◽  
Waterlogging Treatment

We investigated the root distribution and nitrogen fixation activity of American jointvetch (Aeschynomene americanaL.) cv. Glenn, under waterlogging treatment. The plants were grown in pots under three different treatments: no waterlogging (control), 30 days of waterlogging (experiment 1), and 40 days of waterlogging (experiment 2). The plants were subjected to the treatments on day 14 after germination. Root dry matter (DM) weight distribution of waterlogged plants was shallower than controls after day 20 of waterlogging. Throughout the study period, the total root DM weight in waterlogged plants was similar to that in the controls. Enhanced rooting (adventitious roots) and nodule formation at the stem base were observed in waterlogged plants after day 20 of waterlogging. The average DM weight of individual nodules on the region of the stem between the soil surface and water surface of waterlogged plants was similar to that of individual taproot nodules in the controls. Waterlogged plants had slightly greater plant DM weight than the controls after 40 days of treatment. The total nitrogenase activity (TNA) of nodules and nodule DM weight were higher in waterlogged plants than in the controls. Waterlogged American jointvetch had roots with nodules both around the soil surface and in the area between the soil surface and water surface after 20 days of waterlogging, and they maintained high nitrogenase activity and net assimilation rate that resulted in an increased growth rate.

scholarly journals The effect of inoculation of pea plants with mycorrhizal fungi and Rhizobium on nitrogen and phosphorus assimilation

2011 ◽  
Vol 52 (No. 10) ◽  
pp. 435-440 ◽  
Author(s):  
M. Geneva ◽  
G. Zehirov ◽  
E. Djonova ◽  
N. Kaloyanova ◽  
G. Georgiev ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Mycorrhizal Fungi ◽  
Glomus Mosseae ◽  
Rhizobium Leguminosarum ◽  
Glomus Intraradices ◽  
Plant Biomass ◽  
Phosphorus Level ◽  
Nitrogen And Phosphorus ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity

The study evaluated the response of pea (Pisum sativum cv. Avola) to arbuscular mycorrhizal fungi (AM) species Glomus mosseae and Glomus intraradices and Rhizobium leguminosarum bv. viceae, strain D 293, regarding the growth, photosynthesis, nodulation and nitrogen fixation activity. Pea plants were grown in a glasshouse until the flowering stage (35 days), in 4 kg plastic pots using leached cinnamonic forest soil (Chromic Luvisols – FAO) at P levels 13.2 (P1) and 39.8 (P2) mg P/kg soil. The obtained results demonstrated that the dual inoculation of pea plants significantly increased the plant biomass, photosynthetic rate, nodulation, and nitrogen fixation activity in comparison with single inoculation with Rhizobium leguminosarum bv. viceae strain D 293. On the other hand, coinoculation significantly increased the total phosphorus content in plant tissue, acid phosphatase activity and percentage of root colonization. The effectiveness of coinoculation with Rhizobium leguminosarum and Glomus mosseae was higher at the low phosphorus level while the coinoculation with Glomus intraradices appeared to be the most effective at higher phosphorus level.

scholarly journals Appraising Endophyte–Plant Symbiosis for Improved Growth, Nodulation, Nitrogen Fixation and Abiotic Stress Tolerance: An Experimental Investigation with Chickpea (Cicer arietinum L.)

Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 621 ◽  
Author(s):  
Ahmad ◽  
Naseer ◽  
Hussain ◽  
Zahid Mumtaz ◽  
Mustafa ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Root Nodules ◽  
Abiotic Stress Tolerance ◽  
Paenibacillus Polymyxa ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Pgp Traits ◽  
Paenibacillus Sp

Chickpea is an important leguminous crop that improves soil fertility through atmospheric nitrogen fixation with the help of rhizobia present in nodules. Non-rhizobia endophytes are also capable of inducing nodulation and nitrogen fixation in leguminous crops. The aim of the current study was to isolate, characterize and identify the non-rhizobia endophytic bacterial strains from root nodules of chickpea. For this purpose, more than one hundred isolates were isolated from chickpea root nodules under aseptic conditions and were confirmed as endophytes through re-isolating them from root nodules of chickpea after their inoculation. Nineteen confirmed endophytic bacterial strains revealed significant production of indole acetic acid (IAA) both in presence and absence of L-tryptophan and showed their ability to grow under salt, pH and heavy metal stresses. These strains were evaluated for in vitro plant growth promoting (PGP) traits and results revealed that seven strains showed solubilization of P and colloidal chitin along with possessing catalase, oxidase, urease and chitinase activities. Seven P-solubilizing strains were further evaluated in a jar trial to explore their potential for promoting plant growth and induction of nodulation in chickpea roots. Two endophytic strains identified as Paenibacillus polymyxa ANM59 and Paenibacillus sp. ANM76 through partial sequencing of the 16S rRNA gene showed the maximum potential during in vitro PGP activities and improved plant growth and nodulation in chickpea under the jar trial. Use of these endophytic strains as a potential biofertilizer can help to reduce the dependence on chemical fertilizers while improving crop growth and soil health simultaneously.

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