Cloning and characterization of the nifA gene from Herbaspirillum seropedicae strain Z78

1991 ◽  
Vol 37 (6) ◽  
pp. 425-429 ◽  
Author(s):  
Emanuel M. Souza ◽  
Shigehiro Funayama ◽  
Liu U. Rigo ◽  
Fábio O. Pedrosa
Keyword(s):  
Nitrogen Fixation ◽  
Azospirillum Brasilense ◽  
Genomic Library ◽  
Acetylene Reduction Activity ◽  
Nif Genes ◽  
Herbaspirillum Seropedicae ◽  
Reduction Activity ◽  
Nitrogen Fixation Gene ◽  
Nifa Gene

A genomic library of Herbaspirillum seropedicae was constructed and screened for the nifA gene by complementation of a nifA mutant of Azospirillum brasilense (FP10). A recombinant plasmid, pEMS1, capable of restoring acetylene reduction activity in the mutant FP10, was isolated and found to hybridize to the nifA gene of Klebsiella pneumoniae. The results suggest that nifA is involved in the regulation of nif genes in H. seropedicae. Key words: diazotroph, nitrogen fixation gene, nif regulation, complementation cloning, Herbaspirillum seropedicae.

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.

IN SITU NITROGEN FIXATION BY WHITE CLOVER IN MIXED SWARDS IN NOVA SCOTIA

1984 ◽  
Vol 64 (3) ◽  
pp. 625-636 ◽  
Author(s):  
J. K. VESSEY ◽  
D. G. PATRIQUIN
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Management Strategy ◽  
Acetylene Reduction Activity ◽  
Total Rainfall ◽  
Reduction Activity ◽  
Main Factors ◽  
Low Levels ◽  
A Site

At three sites, clover cover increased from less than 10% in April to 50–70% during anthesis in July. It began to decline in September, reaching 20–30% in December. Acetylene-reduction activity (ARA), measured by an in situ technique, commenced in April when soil temperature was 5–7 °C. "Clover-specific ARA" (ARA measured in clover patches where cover of clover was 100%) was generally high through most of May, June and July, and then declined, reaching low levels by November. Clover-specific ARA was correlated with total rainfall during the period between 7 and 28 days before the assay (r = 0.720, P < 0.01). The amount of N2 fixed by white clover over a 1-yr period was estimated at 66 and 81 kg N/ha for two pasture sites and 100 kg N/ha at a lawn site. Clover cover and thermal regime appeared to be the two main factors influencing the amount of N2 fixed by white clover at a site. Eight sites of widely varying clover cover (2–53%) were compared in July with regard to cover, clover-specific ARA, edaphic characteristics and fertilizer and grazing management. Management strategy appeared to have the greatest influence on clover abundance in pasture.Key words: White clover, Trifolium repens, nitrogen fixation

Nitrogen fixation activity by white clover pastures during flood irrigation cycles

1988 ◽  
Vol 39 (3) ◽  
pp. 409 ◽  
Author(s):  
GN Mundy ◽  
HR Jones ◽  
WK Mason
Keyword(s):  
Nitrogen Fixation ◽  
Water Stress ◽  
White Clover ◽  
Nitrogen Fertilizer ◽  
Ethylene Production ◽  
Acetylene Reduction ◽  
Acetylene Reduction Activity ◽  
Flood Irrigation ◽  
Reduction Activity ◽  
Nitrogen Fixation Activity

The effect of flood irrigation on clover nitrogen fixation (acetylene reduction activity) was investigated in unfertilized pastures and pastures fertilized with 100 kg N/ha as NH4N03. During the experiment acetylene reduction activities were monitored between successive flood irrigations. The rate of ethylene production increased with decreasing soil water content, peaking 13 days after irrigation. Measured nodule activity then declined, possibly owing to water stress. Nitrogen fertilizer reduced acetylene reduction activities to about half that of the unfertilized pastures. For most of the irrigation cycle acetylene reduction by the pasture was below the measured maximum.

A Spot Test for Estimating Ureides in Soyabean Petioles

1986 ◽  
Vol 22 (4) ◽  
pp. 405-416 ◽  
Author(s):  
Richard A. Glenister ◽  
Thomas A. LaRue
Keyword(s):  
Nitrogen Fixation ◽  
Spot Test ◽  
Acetylene Reduction Activity ◽  
Colorimetric Determination ◽  
Reduction Activity ◽  
Nitrogen Fixation Activity ◽  
Bright Pink ◽  
Low Nitrogen ◽  
Petiole Segment

SUMMARYThe ureides allantoic acid and allantoin form a bright pink compound with acidic p-dimethylamino cinnamaldehyde. It is possible to estimate the ureide content of a soyabean petiole segment by crushing it on filter paper and developing the colour with this reagent. There is a strong correlation between the spot test and estimates from colorimetric determination of ureides. In field grown soyabeans, there was a positive correlation between the petiole ureide content during pod fill and the integrated seasonal acetylene reduction activity. The spot test can be used to identify plants with low nitrogen fixation activity.

Characterization of the fixABC region of Azorhizobium caulinodans ORS571 and identification of a new nitrogen fixation gene

1988 ◽  
Vol 214 (3) ◽  
pp. 496-502 ◽  
Author(s):  
P. Alexandre Kaminski ◽  
Françoise Norel ◽  
Nicole Desnoues ◽  
Anil Kush ◽  
Giovanni Salzano ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Azorhizobium Caulinodans ◽  
Azorhizobium Caulinodans Ors571 ◽  
Nitrogen Fixation Gene

Variabilité génotypique de l'aptitude à la fixation symbiotique de l'azote chez Acacia cyanophylla Lindl.

1999 ◽  
Vol 77 (1) ◽  
pp. 77-86
Author(s):  
Hafedh Nasr ◽  
Tahar Sghaier ◽  
Mohamed Habib Ghorbal ◽  
Yvon René Dommergues
Keyword(s):  
Nitrogen Fixation ◽  
Factorial Analysis ◽  
Qualitative Assessment ◽  
Behaviour Pattern ◽  
Acetylene Reduction Activity ◽  
Genotypic Variability ◽  
Reduction Activity ◽  
Acacia Cyanophylla ◽  
Rhizobium Strains ◽  
Seed Origin

Genotypic variability of the symbiotic nitrogen fixation ability on Acacia cyanophylla Lindl. The phenotypic and functional characteristics of four rhizobium strains isolated from nodules of Acacia cyanophylla Lindl., syn. Acacia saligna (Labill.) H. Wendl., and the inoculated host-plant genetic variability were evaluated. The evaluation used permitted the ranking of the tested rhizobium strains and seedlots according to their performance. The growth pattern of these strains indicated that A. cyanophylla was able to nodulate and fix N2 with slow- and fast-growing rhizobium strains. The acetylene reduction activity test reflected a variable effectiveness of the strains depending on their site of isolation. Strains RFH383 and RFH483 were more effective than RFH183 and RFH283. The high antibiotic resistance acquisition by RFH183 and RFH283 strains seemed to be inversely related to their effectiveness. Acacia cyanophylla seedlings from five seedlots displayed a high variability regarding their growth, nodulation, and ability to fix nitrogen. The ability to fix nitrogen was greater in the seedlings from KL seedlot than those from EN, KR, and TZ seedlots. The qualitative assessment of the seedlots using correspondence factorial analysis showed that the seedlings from KL seedlot preformed better than those from KR and TZ. The seedlings from TN and EN seedlots displayed an intermediate behaviour pattern. Seed origin seemed to affect the growth, nodulation, and nitrogen fixation of inoculated A. cyanophylla. The behaviour of this species and that of its associated rhizobium strains appeared to be very sensitive to variations in site characteristics. Results suggested that the association between plants derived from KL seedlot and RFH383 strain may represent the best partnership allowing the improvement of symbiotic nitrogen fixation.Key words: Acacia cyanophylla, rhizobium, nodulation, N2 fixation, genotypic variability, correspondence factorial analysis.

Isolation and characterization of rhizobiophages specific for Bradyrhizobium japonicum USDA 117

1986 ◽  
Vol 32 (4) ◽  
pp. 326-329 ◽  
Author(s):  
F. M. Hashem ◽  
J. S. Angle ◽  
P. A. Ristiano
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Generation Time ◽  
Burst Size ◽  
Maximum Size ◽  
Acetylene Reduction Activity ◽  
Reduction Activity ◽  
Isolation And Characterization ◽  
Mutant Phage ◽  
Shoot Weight

The isolation and characterization of two phages specific for Bradyrhizobium japonicum USDA 117 are reported. The original phage was isolated from a Chester silt loam soil cropped to soybeans. A mutant of this isolate was obtained during long-term incubation in soil of the original isolate. Both phages were specific for B. japonicum USDA 117. The primary distinction between the two phages was the plaque size produced on the host. The original isolate produced plaques with a maximum size of 2.2 mm2. The mutant phage produced plaques with a maximum size of 11.4 mm2. Both phages exhibited similar morphologies. The head was hexagonal in shape with a diameter of 60 nm. An adsorption rate experiment revealed that the mutant phage was adsorbed faster to the host than the original isolate. Maximum adsorption of the original isolate to the host occurred after 10 min, while the mutant phage required 7 min. Characterization of the original isolate in a one-step growth experiment revealed that the burst size, rise period, and generation time were 100 plaque-forming units/cell, 12 min, and 80 min, respectively. A similar experiment for the mutant phage demonstrated a burst size, rise period, and generation time of 210 plaque-forming units/cell, 6 min, and 70 min, respectively. The ecological competitiveness of the mutant phage appeared to have been altered. In a greenhouse soil incubation experiment, the original isolate reduced nodule number, nodule weight, shoot weight, and acetylene reduction activity to a significantly greater extent than the mutant phage. These results indicate that, while the overall growth rate of the mutant phage was faster, it was less efficient in its parasitism of its host.

Nitrogen fixation by naturally occurring duckweed–cyanobacterial associations

1985 ◽  
Vol 31 (4) ◽  
pp. 327-330 ◽  
Author(s):  
Tran Phuoc Duong ◽  
James M. Tiedje
Keyword(s):  
Nitrogen Fixation ◽  
Annual Cycle ◽  
Acetylene Reduction ◽  
Acetylene Reduction Activity ◽  
Lower Epidermis ◽  
Reduction Activity ◽  
Naturally Occurring ◽  
Favorable Environment ◽  
Nitrogen Inputs

Nitrogen fixation as measured by acetylene conversion to ethylene was found to be common for duckweed blooms on ponds, lakes, and streams in Michigan. Twenty-six of 29 sites with duckweed sampled over a 2-year period showed acetylene reduction activity (ARA). These activities corresponded to N inputs of 3.7–7.5 kg N∙ha−1 per annual cycle for typical blooms but dense Lemna trisulca blooms could be 10 times greater. The ARA was stimulated five- to six-fold by light, was not removed when plants were shaken in water, and was usually associated with the leaves and not the roots. Colonies of heterocyst-bearing cyanobacteria of the genera Nostoc, Gloeotrichia, Anabaena, Calothrix, and Cylindrospermum were observed attached to the lower epidermis or in the reproductive pockets of leaves of Spirodela and Lemna plants but not on Wolffia plants. The ARA correlated reasonably well with the density of cyanobacterial colonies observed. The duckweed appeared to provide a more favorable environment for the cyanobacteria which should result in enhanced nitrogen inputs to aquatic and sediment environments harboring duckweed. The N2 fixation was not sufficient, however, to meet all the nitrogen needs of the duckweed bloom.

Corrigendum - Nitrogen fixation activity by white clover pastures during flood irrigation cycles

1988 ◽  
Vol 39 (3) ◽  
pp. 409
Author(s):  
GN Mundy ◽  
HR Jones ◽  
WK Mason
Keyword(s):  
Nitrogen Fixation ◽  
Water Stress ◽  
White Clover ◽  
Nitrogen Fertilizer ◽  
Ethylene Production ◽  
Acetylene Reduction ◽  
Acetylene Reduction Activity ◽  
Flood Irrigation ◽  
Reduction Activity ◽  
Nitrogen Fixation Activity

The effect of flood irrigation on clover nitrogen fixation (acetylene reduction activity) was investigated in unfertilized pastures and pastures fertilized with 100 kg N/ha as NH4N03. During the experiment acetylene reduction activities were monitored between successive flood irrigations. The rate of ethylene production increased with decreasing soil water content, peaking 13 days after irrigation. Measured nodule activity then declined, possibly owing to water stress. Nitrogen fertilizer reduced acetylene reduction activities to about half that of the unfertilized pastures. For most of the irrigation cycle acetylene reduction by the pasture was below the measured maximum.

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