Assessment of strains of Bradyrhizobium sp. (Lupinus) for serradellas (Ornithopus spp.)

1996 ◽  
Vol 36 (1) ◽  
pp. 63 ◽  
Author(s):  
RA Ballard
Keyword(s):  
Nitrogen Fixation ◽  
Sandy Soils ◽  
Fold Increase ◽  
Annual Production ◽  
Total Annual Production ◽  
Bradyrhizobium Sp ◽  
Commercial Inoculant ◽  
Inoculant Strain ◽  
Early Production

Several strains of Bradyrhizobium sp. (Lupinus) were compared, in the glasshouse and field, with the Australian commercial inoculant strain, WU42.5, for symbiotic performance on serradella. Strains WSM471 and USDA3709 were more effective in nitrogen fixation (12 and 8% respectively) than WU42.5 across 10 serradella lines, although WU42.5 generally displayed good levels of effectiveness. WSM471 was a more saprophytically competent strain than WU425 in mildly acidic sandy soils, resulting in a 2.8-fold increase in the nodule score of serradella sown 32 cm from a line of bradyrhizobia established the previous year. Although WSM471, when compared with WU42.5, increased the nodulation and early production of an established sward of serradella, it did not improve total annual production of the sward. The possible replacement of WU42.5 with WSM471 in serradella inoculants is discussed.

An evaluation of potential Rhizobium inoculant strains used for pulse production in acidic soils of south-east Australia

2005 ◽  
Vol 45 (3) ◽  
pp. 257 ◽  
Author(s):  
J. Evans
Keyword(s):  
Nitrogen Fixation ◽  
Relative Humidity ◽  
Western Australia ◽  
Faba Bean ◽  
Field Experiments ◽  
Collaborative Study ◽  
Field Pea ◽  
Acidic Soil ◽  
Wide Range ◽  
Inoculant Strain

Profitability of the pulse industry relies considerably on crop nitrogen fixation because this process supplies greater than 60% of pulse crop nitrogen. Therefore the industry requires the most efficient Rhizobium symbioses and effective inoculation management. Re-appraisal of the recommended inoculant strain for field pea, SU303, in south-east Australia, was warranted by field evidence that SU303 failed to maximise grain yield at sites in Western Australia. Re-appraisal of the inoculant strain for faba bean and lentil, WSM1274, was warranted because of anecdotal evidence from Western Australia of associated crop failures. In addition, a glasshouse study in Western Australia reported greater dry matter production by faba bean and lentil inoculated with strains other than WSM1274. This paper reports trials comparing potential inoculant strains for field pea and faba bean in soils of south-east Australia. Comparisons are based on efficiency for nitrogen fixation, survival on seed and survival in soil. Additionally, because the pulse industry lacked comprehensive information to assist decision making on the need for recurring inoculation, relevant investigation of this issue is also reported. The results of 3 field experiments for efficiency for nitrogen fixation, over mildly (pHCa 5.0) to strongly (pHCa 4.3) acidic soil in south-east Australia supported replacing SU303 as the commercial inoculant. The efficiency for nitrogen fixation of WSM1274 on faba bean was not found to be inferior to alternative strains. However, its capacity for survival on seed at temperatures of 15°C and above, over a wide range of relative humidity, and perhaps its capacity for survival in acidic soil, was inferior. This provided additional evidence to justify the replacement of this inoculant strain that was agreed to by a national steering committee in 2001, based on the Western Australia reports, the early experiments in this study and those of a collaborative study in Victoria. Alternative inoculant strains to SU303 and WSM1274 were identified in the current study. Temperature and relative humidity conditions suitable for maintaining inoculant viability with extended storage of inoculated field pea and faba bean are also discussed. A survey of rhizobia surviving in soil was used to determine the time scale of persistence of Rhizobium leguminosarum bv. viciae and Bradyrhizobium sp. (Lupinus) in soils of the south-east. It was concluded that in soils of pH (CaCl2) <5.1, inoculation of field pea and faba bean should be routinely practiced; none of the strains of R. leguminosarum bv. viciae tested showed ability for survival in strongly acidic soil sufficient to obviate seed inoculation. It was further concluded that the absence of a legume host for lupin rhizobia for 4 or more years would also warrant reintroducing inoculant of B. sp. (Lupinus).

Regrowth of smooth bromegrass (Bromus inermis Leyss.) following defoliation

1994 ◽  
Vol 74 (3) ◽  
pp. 531-537 ◽  
Author(s):  
T. Harrison ◽  
J. T. Romo
Keyword(s):  
Vegetative Growth ◽  
Early Spring ◽  
Bromus Inermis ◽  
Annual Production ◽  
Growth Stages ◽  
Forage Production ◽  
Smooth Bromegrass ◽  
Total Annual Production ◽  
Growing Conditions ◽  
Reproductive Phases

Regrowth and production of tillers in smooth bromegrass (Bromus inermis Leyss.) following defoliation to a 5-cm stubble height were monitored throughout the summer and in early spring the following year in central Saskatchewan. After defoliation, while smooth bromegrass was vegetative, forage began accumulating in 45–75 growingdegree-days (GDD) when moisture was favorable. Regrowth ranged from 34 to 84 g m−2. Plants also produced ≤ 51 g m−2 of regrowth when defoliated at or before culm elongation in a year with above-average precipitation. In two dry years, regrowth was minimal and plants did not regrow after defoliation in the later vegetative growth stages; however, new leaves were produced within 110–140 GDD. Following defoliation at early vegetative growth stages, 1030–1180 GDD were needed to reach maximum regrowth. Total annual production was either unaffected or reduced by defoliation. Total annual production ranged from 35 to 139 g m−2, with yields lowest when defoliated in early May or early June and highest when herbage was removed in mid-May or near flowering and seed production. When plants were defoliated during vegetative growth most tillers were produced the following spring, whereas when plants were defoliated during reproductive phases the majority of tillers emerged in the fall. The year after defoliation, the density of tillers (871–951 m−2) was not significantly different among treatments. Regrowth following defoliation cannot be related to a particular growth stage, but rather it depends on growing conditions. If smooth bromegrass is defoliated once and rested until the next year, it should be recovered by early spring and its productivity should be unaffected. Key words: Etiolated growth, forage production, grazing management, regrowth, rest requirement, tillering

scholarly journals Regulation of Nitrogen Fixation in Bradyrhizobium sp. Strain DOA9 Involves Two Distinct NifA Regulatory Proteins That Are Functionally Redundant During Symbiosis but Not During Free-Living Growth

2018 ◽  
Vol 9 ◽  
Author(s):  
Jenjira Wongdee ◽  
Nantakorn Boonkerd ◽  
Neung Teaumroong ◽  
Panlada Tittabutr ◽  
Eric Giraud
Keyword(s):  
Nitrogen Fixation ◽  
Regulatory Proteins ◽  
Free Living ◽  
Bradyrhizobium Sp

Production and Movement of Juvenile Rainbow Trout (Salmo gairdneri) in a Headwater of Bothwell's Creek, Georgian Bay, Canada

1974 ◽  
Vol 31 (1) ◽  
pp. 117-121 ◽  
Author(s):  
D. Ross Alexander ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Great Lakes ◽  
Annual Production ◽  
Salmo Gairdneri ◽  
Ecological Disturbance ◽  
Georgian Bay ◽  
Juvenile Rainbow Trout ◽  
Total Annual Production ◽  
Calculated Ratio

Within the 21,500 m2 headwater, the standing population of juvenile rainbow trout reached a high of 7.05 g/m2 in October. Production was maximum during August at 1.77 g/m2. Total annual production is calculated at 284.5 kg (13.2 g/m2). Spring emigrants (no less than 4830 fish weighing 69 kg) were age I (91%) and age II. Minimum calculated ratio of production to yield as emigrants was 4.1:1. Comparatively few age 0 fish emigrated during summer. Because of their demonstrated capability to produce juveniles, sensitive headwaters must be preserved from ecological disturbance to assure self-perpetuating rainbow trout populations in the Great Lakes.

scholarly journals Competition, Nodule Occupancy, and Persistence of Inoculant Strains: Key Factors in the Rhizobium-Legume Symbioses

2021 ◽  
Vol 12 ◽  
Author(s):  
Marcela Mendoza-Suárez ◽  
Stig U. Andersen ◽  
Philip S. Poole ◽  
Carmen Sánchez-Cañizares
Keyword(s):  
Nitrogen Fixation ◽  
Current Knowledge ◽  
Local Environment ◽  
Nitrogen Fertilizers ◽  
Superior Performance ◽  
Nodule Occupancy ◽  
Inoculant Strain ◽  
Native Strains ◽  
Biological Nitrogen ◽  
Rhizobial Inoculants

Biological nitrogen fixation by Rhizobium-legume symbioses represents an environmentally friendly and inexpensive alternative to the use of chemical nitrogen fertilizers in legume crops. Rhizobial inoculants, applied frequently as biofertilizers, play an important role in sustainable agriculture. However, inoculants often fail to compete for nodule occupancy against native rhizobia with inferior nitrogen-fixing abilities, resulting in low yields. Strains with excellent performance under controlled conditions are typically selected as inoculants, but the rates of nodule occupancy compared to native strains are rarely investigated. Lack of persistence in the field after agricultural cycles, usually due to the transfer of symbiotic genes from the inoculant strain to naturalized populations, also limits the suitability of commercial inoculants. When rhizobial inoculants are based on native strains with a high nitrogen fixation ability, they often have superior performance in the field due to their genetic adaptations to the local environment. Therefore, knowledge from laboratory studies assessing competition and understanding how diverse strains of rhizobia behave, together with assays done under field conditions, may allow us to exploit the effectiveness of native populations selected as elite strains and to breed specific host cultivar-rhizobial strain combinations. Here, we review current knowledge at the molecular level on competition for nodulation and the advances in molecular tools for assessing competitiveness. We then describe ongoing approaches for inoculant development based on native strains and emphasize future perspectives and applications using a multidisciplinary approach to ensure optimal performance of both symbiotic partners.

scholarly journals Isolation and characterization of plant growth-promoting endophytic bacteria of wild legumes growing on sandy soils of Binh Thuan province, Vietnam

2021 ◽  
Vol 10 (3) ◽  
pp. 246-254
Author(s):  
Dang Thi Ngoc Thanh ◽  
Pham Thi Thu Ly ◽  
Pham Thi Nga ◽  
Pham Van Ngot
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Endophytic Bacteria ◽  
Phosphate Solubilization ◽  
Sandy Soils ◽  
Legume Species ◽  
Bacterial Isolates ◽  
Isolation And Characterization ◽  
Plant Growth Promoting ◽  
Growth Promoting

The roots of two legume species (Tephrosia purpurea and Tephrosia villosa) that grew wild on dry sandy soils of Binh Thuan province were sources for isolating plant growth-promoting endophytic bacteria. Semi-solid LGI medium was used for the isolation of nitrogen-fixing bacteria from root extracts. All bacterial isolates isolates were evaluated for their ability to solubilize calcium orthophosphate on solid NBRIP medium and their ability to produce IAA in Burk's liquid medium supplemented with 100 mg/L tryptophan. The possibilities of nitrogen fixation, phosphate solubilization and IAA synthesis were all quantitative examined by colorimetric method. Twenty-two bacterial isolates of T. purpurea and 18 isolates of T. villosa were capable of nitrogen fixation in the range of 1.94 to 2.81 mg/L NH4+, whereas only 18 isolates of T. purpurea and 16 isolates of T. villosa showed phosphate solubilization in the range of 12.30 – 48.90 mg/L P2O5, and IAA production in the range of 0.38 – 12.72 mg/L. Sixteen outstanding bacterial isolates of the two legume species were identified by MALDI-TOF technique. The results showed that 13 isolates had high similarity with five bacterial genera including Klebsiella, Cronobacter, Enterobacter, Burkholderia, and Bacillus with score values in the range of 2.070 – 2.411.

Biological Nitrogen Fixation and Root-Nodule Bacteria (Rhizobium Sp. and Bradyrhizobium Sp.) In Two Rehabilitating Sand Dune Areas Planted With Acacia Spp

1985 ◽  
Vol 33 (5) ◽  
pp. 595 ◽  
Author(s):  
YM Barnet ◽  
PC Catt ◽  
DH Hearne
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Sand Dune ◽  
Root Nodule ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Bradyrhizobium Sp ◽  
Biological Nitrogen ◽  
Slow Growing ◽  
Rhizobium Sp

This paper reports a study of biological nitrogen fixation in two sand dune regions of New South Wales where planted Acacia spp. had been used in revegetation programmes. At one location (Bridge Hill Ridge), natural regrowth had produced a complex plant community, and native legumes in addition to the planted acacias were present. The other area (Wanda Beach) was a grossly disturbed site which contained only the planted species. Symbiotic fixation in association with Australian legumes occurred at both locations at rates within the range reported by other authors. Distinct seasonal changes were apparent, with higher activities in the cooler months. The legume association seemed the only source of biologically fixed nitrogen at Bridge Hill Ridge, but at Wanda Beach cyanobacteria in an algal mat also made a contribution. Fast and slow-growing bacterial strains were obtained from root nodules of native legumes at both sites and were classed as Rhizobium sp. and Bradyrhizobium sp., respectively. This division was supported by the pattern of serological affinities of the isolates and by differences in their protein profiles demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Two atypical types of root-nodule bacteria were found at Bridge Hill Ridge: non-nodulating, fast-growing isolates and an abnormally slow-growing Bradyrhizobium sp.

scholarly journals nifDK Clusters Located on the Chromosome and Megaplasmid of Bradyrhizobium sp. Strain DOA9 Contribute Differently to Nitrogenase Activity During Symbiosis and Free-Living Growth

2016 ◽  
Vol 29 (10) ◽  
pp. 767-773 ◽  
Author(s):  
Jenjira Wongdee ◽  
Pongpan Songwattana ◽  
Nico Nouwen ◽  
Rujirek Noisangiam ◽  
Joel Fardoux ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Transcriptional Analysis ◽  
Main Role ◽  
Free Living ◽  
Living State ◽  
Bradyrhizobium Sp ◽  
Reporter Strains ◽  
Free Living Conditions

Bradyrhizobium sp. strain DOA9 contains two copies of the nifDK genes, nifDKc, located on the chromosome, and nifDKp, located on a symbiotic megaplasmid. Unlike most rhizobia, this bacterium displays nitrogenase activity under both free-living and symbiotic conditions. Transcriptional analysis using gusA reporter strains showed that both nifDK operons were highly expressed under symbiosis, whereas nifDKc was the most abundantly expressed under free-living conditions. During free-living growth, the nifDKp mutation did not affect nitrogenase activity, whereas nitrogenase activity was drastically reduced with the nifDKc mutant. This led us to suppose that nifDKc is the main contributor of nitrogenase activity in the free-living state. In contrast, during symbiosis, no effect of the nifDKc mutation was observed and the nitrogen-fixation efficiency of plants inoculated with the nifDKp mutant was reduced. This suggests that nifDKp plays the main role in nitrogenase enzyme activity during symbiosis. Together, these data suggest that Bradyrhizobium sp. strain DOA9 contains two functional copies of nifDK genes that are regulated differently and that, depending on their lifestyle, contribute differently to nitrogenase activity.

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