Azospirillum effects on susceptibility to Rhizobium nodulation and on nitrogen fixation of several forage legumes

1987 ◽  
Vol 33 (6) ◽  
pp. 510-514 ◽  
Author(s):  
Eli Yahalom ◽  
Yaacov Okon ◽  
Amos Dovrat
Keyword(s):  
Rhizobium Meliloti ◽  
Root Hairs ◽  
Acetylene Reduction Activity ◽  
Nodule Formation ◽  
Medicago Polymorpha ◽  
Reduction Activity ◽  
Colony Forming Units ◽  
Macroptilium Atropurpureum ◽  
Rhizobium Nodulation ◽  
Increased Susceptibility

Azospirillum brasilense Cd cell concentration of 105–107 colony-forming units (cfu)/mL applied 24 h before Rhizobium (106 cfu/mL), increased nodule formation in the non root hair zone, more than twofold, in pouch-grown Medicagopolymorpha and Macroptilium atropurpureum seedlings, compared with Rhizobium alone. The increase in nodule formation in pouch-grown Trifolium alexandrinum following preinoculation with Azospirillum was 20%. The percentage of nodulated seedlings rose from 0 to 25% when Medicago polymorpha was preinoculated with Azospirillum followed by the application of 10 cfu/mL Rhizobium meliloti, a level which by itself was not sufficient to initiate nodule formation. Acetylene reduction activity in Medicago polymorpha and Macroptilium atropurpureum seedlings after inoculation with Azospirillum–Rhizobium was markedly increased. A possible reason for the increased susceptibility to Rhizobium infection may be that Azospirillum stimulates the formation of a larger number of epidermal cells that differentiate into infectable root hairs.

Root nodule initiation in Gymnostoma (Casuarinaceae) and Shepherdia (Elaeagnaceae) induced by Frankia strain HFPGpI1

1989 ◽  
Vol 67 (10) ◽  
pp. 2873-2879 ◽  
Author(s):  
Suzanne Racette ◽  
John G. Torrey
Keyword(s):  
Root Nodule ◽  
Root Hairs ◽  
Nodule Development ◽  
Acetylene Reduction Activity ◽  
Frankia Strain ◽  
Root Cortex ◽  
Reduction Activity ◽  
Variable Activity ◽  
Plant Families ◽  
Nodule Initiation

Seedlings of Gymnostoma papuanum (Casuarinaceae) and Shepherdia argentea (Elaeagnaceae) were grown in water culture and inoculated with Frankia strain HFPGpI1. Root nodule initiation and early nodule development were examined using light microscopy. Gymnostoma papuanum was infected by penetration of Frankia into deformed root hairs, followed by development of a prenodule region and one to several nodule lobe primordia in the root cortex. Frankia hyphae grew directly through cell walls from cell to cell, colonizing cells of the prenodule prior to invading nodule lobe cells. Shepherdia argentea roots were infected by Frankia via intercellular penetration of the root epidermis and cortex with direct infection of cells of the nodule lobe primordia. No prenodule region was formed. Thus far, the mode of infection appears to be characteristic for each of the plant families. Subsequent to nodule initiation, plants were assayed at 4-week intervals (up to 12 or 16 weeks) for acetylene reduction activity. Low and variable activity was observed. The presence of symbiotic vesicles in G. papuanum nodules is reported as the first instance of vesicles seen in nodules taken from a member of the family Casuarinaceae.

Derivation and molecular characterization of symbiotically deficient mutants of Rhizobium meliloti

1987 ◽  
Vol 33 (9) ◽  
pp. 739-747 ◽  
Author(s):  
G. Selvaraj ◽  
I. Hooper ◽  
S. Shantharam ◽  
V. N. Iyer ◽  
L. Barran ◽  
...  
Keyword(s):  
Rhizobium Meliloti ◽  
Acetylene Reduction Activity ◽  
Wild Type ◽  
Suicide Vector ◽  
Reduction Activity ◽  
Dna Restriction Fragments ◽  
Dna Restriction ◽  
Bona Fide ◽  
Fix Genes

A collection of symbiotically defective mutants of Rhizobium meliloti JJ1c10 was derived by Tn5 mutagenesis using the suicide vector pGS9. They include two Nod− and about 250 Fix− mutants. The mutants were found to be heterogenous in acetylene reduction activity and in the morphology and ultrastructure of the nodules which they induced. Over 90% were found to contain bona fide Tn5 insertions in a variety of DNA restriction fragments. When Tn5-carrying DNA segments cloned from 24 of the mutants were introduced into the equivalent location in the genome of the wild-type strain by recombination-mediated replacement, only eight produced a symbiotically defective phenotype similar to that of the original mutant. This result indicated that many of the symbiosis mutations were not directly caused by Tn5 insertion. DNA segments apparently containing mutated fix genes but not containing Tn5 were found in eight mutants by identifying cosmids carrying wild-type DNA which complemented their symbiosis defects. Probing of the DNA of these mutants with their complementing cosmids revealed no detectable physical alteration of the homologous DNA. A segment of DNA including the hsn and nifHDK genes was favoured for these non-Tn5 mutations. Three regions of the genome in which Tn5 caused fix mutations were identified. One of these was the known megaplasmid nod-nif region. The other two regions, designated fix-e5 and fix-h21, were found to be chromosomal. Mutants in one of these chromosomal regions fluoresced more intensely on calcofluor plates than the wild type.

Nitrogen fixation associated with 'Park' Kentucky bluegrass (Poapratensis L.)

1979 ◽  
Vol 25 (10) ◽  
pp. 1197-1200 ◽  
Author(s):  
R. C. Shearman ◽  
W. L. Pedersen ◽  
R. V. Klucas ◽  
E. J. Kinbacher
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Acetylene Reduction Activity ◽  
Controlled Environment ◽  
Nitrogen Accumulation ◽  
Reduction Activity ◽  
Significant Difference ◽  
Reduction Assay

Associative nitrogen fixation in Kentucky bluegrass (Poa pratensis L.) turfs inoculated with five nitrogen-fixing bacterial isolates was evaluated using the acetylene reduction assay and nitrogen accumulation as indicators of fixation. 'Park' and 'Nugget' Kentucky bluegrass turfs were grown in controlled environment chambers and inoculated with Klebsiella pneumoniae (W-2, W-6, and W-14), Erwinia herbicola (W-8), and Enterobacter cloacae (W-11). 'Park' inoculated with K. pneumoniae (W-6) had significant acetylene reduction activity using undisturbed turfs. Other treatments including turfs treated with heat-killed cells had no significant difference in acetylene reduction. In a second study, 'Park' and 'South Dakota Certified' turfs were grown in a greenhouse and inoculated with K. pneumoniae (W-6) and E. herbicola (W-8). 'Park' inoculated with K. pneumoniae (W-6) had increased acetylene reduction activity rates and also a greater nitrogen accumulation in aerial tissues when compared to controls. Acetylene reduction activity was correlated (r = 0.92) to nitrogen accumulation. Other treatments did not effectively increase acetylene reduction activity or nitrogen accumulation.

Acetylene reduction activity associated with tree roots in cypress wetlands

1981 ◽  
Vol 13 (6) ◽  
pp. 555-557 ◽  
Author(s):  
Forrest E. Dierberg ◽  
Patrick L. Brezonik
Keyword(s):  
Acetylene Reduction ◽  
Acetylene Reduction Activity ◽  
Tree Roots ◽  
Reduction Activity

Azospirillum–Rhizobium interaction leading to a plant growth stimulation without nodule formation

1985 ◽  
Vol 31 (11) ◽  
pp. 1026-1030 ◽  
Author(s):  
Jacek Plazinski ◽  
Barry G. Rolfe
Keyword(s):  
Plant Growth ◽  
White Clover ◽  
Nitrogen Deficiency ◽  
Growth Stimulation ◽  
Selective Medium ◽  
Acetylene Reduction Activity ◽  
Nodule Formation ◽  
Bacterial Cells ◽  
Indigenous Plasmid ◽  
Plant Growth Stimulation

The effect of inoculation of white clover plants with mixed cultures of Rhizobium trifolii strain ANU870 and Azospirillum brasilense strain SP245 was examined. Ratios of Rhizobium–Azospirillum (R:A) of 1:200 to 1:2500 caused an inhibition of nodulation. However, these nonnodulated plants did not show nitrogen-deficiency symptoms when grown on nitrogenfree medium. When these plants were assayed for acetylene reduction activity a low level of ethylene production was detected. A significant increase in plant dry weights was also observed. Isolation of viable bacterial cells from surface-sterilized root segments of plants inoculated with an R:A ratio of 1:200 revealed that 80% of the bacterial population was made up of the Azospirillum strain. Under laboratory conditions transfer of the Rhizobium Sym(biosis) plasmid pBRIAN to strain SP245 was observed ex planta. However, the Sym plasmid was unstable in Azospirillum. A high frequency of Tn5 transfer from pBRIAN to strain SP245 occurred when strains ANU870 and SP245 were mixed in the rhizosphere and (or) in the root tissue. Tn5 transposed preferentially into the smallest indigenous plasmid of strain SP245 and was easily lost when this strain (SP245::Tn5) was not maintained on selective medium. This mutated Azospirillum strain caused plant growth stimulation when inoculated onto white clover plants.

Nitrogenase Activity by Subterranean Clover and Other Temperate Pasture Legumes

1988 ◽  
Vol 15 (5) ◽  
pp. 657 ◽  
Author(s):  
AG Davey ◽  
RJ Simpson
Keyword(s):  
Root Respiration ◽  
Nitrogenase Activity ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Acetylene Reduction Activity ◽  
Diffusion Resistance ◽  
Pasture Legumes ◽  
Reduction Activity ◽  
Decline Rate ◽  
Nodulated Root

Nitrogenase (C2H2-reduction) activity and nodulated root respiration of intact plants of subterranean clover (Trifolium subterraneum L.) cv. Seaton Park nodulated by Rhizobium trifolii WU95 were measured in a flow-through system. Simultaneous declines in nitrogenase activity and respiration were exhibited 2 min after 10% C2H2 had been introduced into the gas stream. Declines in nitrogenase activity and nodulated root respiration provided an estimate of the efficiency of nitrogenase activity (mol CO2 evolved/mol C2H4 produced). The pre-decline rate of nitrogenase activity at time zero was thus calculated as the product of the respiration associated with nitrogenase activity and the reciprocal of the efficiency of nitrogenase activity. Pre-decline rates of nitrogenase activity were similar to peak rates for several pasture legumes. However, post-decline rates of activity were as much as 70% lower than the pre-decline rate. The age of subterranean clover plants had an important influence on the magnitude of the C2H2-induced decline; young plants exhibited the largest C2H2-induced inhibition of nitrogenase activity. Neither sainfoin (Onobrychis viciifolia Scop.) cv. Othello nodulated by Rhizobium sp. CC1108 nor yellow serradella (Ornithopus compressus L.) cv. Pitman nodulated by R. lupini WU425 exhibited C2H2-induced declines in nitrogenase activity. Nitrogenase-linked respiration of subterranean clover at the 14-leaf stage accounted for 50% of total nodulated root respiration. The oxygen diffusion resistance of the nodules increased in the presence of C2H2 but the effect was reversible once C2H2 was removed from the gas atmosphere. The pre-decline rate of acetylene reduction activity of subterranean clover reached a maximum at 10% C2H2. The C2H2-induced decline in nitrogenase activity was lower at subsaturating pC2H2 and was not detected at 0.4% C2H2.

scholarly journals Seedling treatments and phosphorus solution concentrations affect nodulation and nodule functions in soybean (Glycine max L.)

2008 ◽  
Vol 53 (No. 2) ◽  
pp. 65-71 ◽  
Author(s):  
S.J. Miao ◽  
X.Z. Han ◽  
X.B. Liu ◽  
Y.F. Qiao
Keyword(s):  
Glycine Max ◽  
Plant Biomass ◽  
Dry Weight ◽  
Solution Culture ◽  
Acetylene Reduction Activity ◽  
Nodule Size ◽  
Reduction Activity ◽  
P Content ◽  
Significant Difference ◽  
Nutrient Solution Culture

The effect of three seedling treatments: T<sub>0</sub>, normal germination; T<sub>1</sub>, cotyledons removed; T<sub>2</sub>, cotyledons removed 5 days earlier than in T<sub>1</sub>; and two phosphorus levels (P<sub>0</sub> and P<sub>30</sub>) on nodulation and nodule function in soybean [<i>Glycine max</i> (L.) Merr.] were investigated in nutrient solution culture. The number of nodules formed at P<sub>0</sub> was in the order T<sub>2</sub> > T<sub>0</sub> > T<sub>1</sub>, but it was T<sub>0</sub> > T<sub>2</sub> > T<sub>1</sub> at P<sub>30</sub>. Nodule dry weight per plant had the same tendency as the nodule number. Nodule size (dry weight per nodule) in seedlings ranged from 0.601 to 1.089 mg in the order T<sub>0</sub> > T<sub>1</sub> > T<sub>2</sub>, regardless of P level. For example, nodule size in T<sub>0</sub> was larger by 86% and 52% than T<sub>2</sub> at P<sub>0</sub> and P<sub>30</sub>, respectively. Furthermore, regardless of P level, a specific acetylene reduction activity (ARA, &micro;M C<sub>2</sub>H<sub>4</sub>/h/g nodule) increased with P content in seedlings, but no significant difference was found (<i>P</i> < 0.05). Leghemoglobin (Lb) content was not significantly affected by P level; however, seedlings (T<sub>0</sub> and T<sub>1</sub>) significantly affected the Lb content per unit plant biomass (<i>P</i> < 0.05). All these results suggest that seedling P content plays a key role in nodulation and nodule function of soybean.

scholarly journals Diversity and Effectivity of Indigenous Mesorhizobium Strains for Chickpea (Cicer arietinum L.) in Myanmar

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 287 ◽  
Author(s):  
Khin Myat Soe ◽  
Aung Zaw Htwe ◽  
Kyi Moe ◽  
Abiko Tomomi ◽  
Takeo Yamakawa
Keyword(s):  
Sequence Analysis ◽  
Cicer Arietinum ◽  
Acetylene Reduction ◽  
Dry Weight ◽  
Acetylene Reduction Activity ◽  
Rrna Gene ◽  
Cicer Arietinum L ◽  
Reduction Activity ◽  
Legume Production ◽  
High Level

Chickpea (Cicer arietinum L.) is one of the world’s main leguminous crops that provide chief source of food for humans. In the present study, we characterized thirty isolates of indigenous chickpea rhizobia from Myanmar based on the sequence analysis of the bacterial 16S rRNA gene. The sequence analysis confirmed that all isolates were categorized and identified as the genus Mesorhizobium and they were conspecific with M. plurifarium, M. muliense, M. tianshanense, and M. sp. This is the first report describing M. muliense, M. tianshanense, and M. plurifurium from different geographical distribution of indigenous mesorhizobia of chickpea in Myanmar. In order to substitute the use of chemical fertilizers in legume production, there is a need for the production of Biofertilizers with rhizobial inoculants. The effectiveness of Myanmar Mesorhizobim strains isolated from soil samples of major chickpea growing areas of Myanmar for plant growth and nitrogen fixation were studied in pot experiments. The nodule dry weight and acetylene reduction activity of the plant inoculated with Mesorhizobium tianshanense SalCP19 was significantly higher than the other tested isolates in Yezin-4 chickpea variety. But, Mesorhizobium sp. SalCP17 was showed high level of acetylene reduction activity per plant in Yezin-6 chickpea variety.

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