scholarly journals Regulation of Phosphorus Supply on Nodulation and Nitrogen Fixation in Soybean Plants with Dual-Root Systems

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2354
Author(s):  
Hongyu Li ◽  
Xiangxiang Wang ◽  
Quanxi Liang ◽  
Xiaochen Lyu ◽  
Sha Li ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Nutrient Solution ◽  
Phosphorus Content ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Sand Culture ◽  
Soybean Plant ◽  
High Concentration ◽  
Grafting Technique ◽  
Phosphorus Application

Phosphorus (P) is an important nutrient affecting nodulation and nitrogen fixation in soybeans. To further investigate the relationship of phosphorus with soybean nodulation and nitrogen fixation, the seedling grafting technique was applied in this study to prepare dual-root soybean systems for a sand culture experiment. From the unfolded cotyledon stage to the initial flowering stage, one side of each dual-root soybean system was irrigated with nutrient solution containing 1 mg/L, 31 mg/L, or 61 mg/L of phosphorus (phosphorus-application side), and the other side was irrigated with a phosphorus-free nutrient solution (phosphorus-free side), to study the effect of local phosphorus supply on nodulation and nitrogen fixation in soybean. The results are described as follows: (1) Increasing the phosphorus supply increased the nodules weight, nitrogenase activity, ureide content, number of bacteroids, number of infected cells, and relative expression levels of nodule nitrogen fixation key genes (GmEXPB2, GmSPX5, nifH, nifD, nifK, GmALN1, GmACP1, GmUR5, GmPUR5, and GmHIUH5) in root nodules on the phosphorus-application side. Although the phosphorus-application and phosphorus-free sides demonstrated similar changing trends, the phosphorus-induced increases were more prominent on the phosphorus-application side, which indicated that phosphorus supply systematically regulates nodulation and nitrogen fixation in soybean. (2) When the level of phosphorus supply was increased from 1 mg/L to 31 mg/L, the increase on the P– side root was significant, and nodule phosphorus content increased by 57.14–85.71% and 68.75–75.00%, respectively; ARA and SNA were 218.64–383.33% and 11.41–16.11%, respectively, while ureide content was 118.18–156.44%. When the level of phosphorus supply was increased from 31mg/L to 61mg/L, the increase in the regulation ability of root and nodule phosphorus content, ARA, SNA, and ureide content were low for roots, and the value for nodules was lower than when the phosphorus level increased from 1 mg/L to 31 mg/L. (3) A high-concentration phosphorus supply on one side of a dual-root soybean plant significantly increased the phosphorus content in the aboveground tissues, as well as the roots and nodules on both sides. In the roots on the phosphorus-free side, the nodules were prioritized for receiving the phosphorus transported from the aboveground tissues to maintain their phosphorus content and functionality.

Phosphorus-Rhizobium interaction studies on biological nitrogen fixation and yield of lentil

1988 ◽  
Vol 110 (1) ◽  
pp. 141-144 ◽  
Author(s):  
K. K. Dhingra ◽  
H. S. Sekhon ◽  
P. S. Sandhu ◽  
S. C. Bhandari
Keyword(s):  
Nitrogen Fixation ◽  
Grain Yield ◽  
Biological Nitrogen Fixation ◽  
Field Experiments ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Dry Weight ◽  
Biological Nitrogen ◽  
Phosphorus Application ◽  
Intact Root

SummaryField experiments were conducted at the Punjab Agricultural University, Ludhiana from 1980–1 to 1984–5 to study the response of lentil genotypes to phosphorus application and Rhizobium inoculation. The number and dry weight of nodules increased consistently with increasing rates of application of phosphorus from 0 to 60 kg P2O5/ha. Nitrogenase activity of intact root nodules increased from 17 530 to 22 390 nmol/h per g dry weight of nodules with 20 kg P2O6/ha and to 27391 and 29170 nmol/h per g with 40 and 60 kg P2O5/ha, respectively. Rhizobium inoculation also increased nodulation, nitrogenase activity and grain yield. Interaction between phosphorus and Rhizobium inoculation was significant in 3 out of 5 years, indicating that the combination of Rhizobium and 20 kg P2O6/ha gave yield equivalent to 40 kg P2O6/ha without Rhizobium.

Starch content and activities of starch-metabolizing enzymes in effective and ineffective root nodules of soybean

1991 ◽  
Vol 69 (4) ◽  
pp. 697-701 ◽  
Author(s):  
Sharon I. Forrest ◽  
Desh Pal S. Verma ◽  
Rajinder S. Dhindsa
Keyword(s):  
Nitrogen Fixation ◽  
Starch Content ◽  
Root Nodules ◽  
Starch Synthase ◽  
Nodule Development ◽  
Wild Type ◽  
Starch Phosphorylase ◽  
High Concentration ◽  
Key Words Nitrogen Fixation ◽  
Glycine Max L

Starch content and activities of some enzymes of starch metabolism were determined in wild-type, N2-fixing (fix+) nodules and in two non-N2-fixing (fix−) nodules induced by Bradyrhizobium japonicum mutant strains, T5-95 and T8-1, on soybean (Glycine max L.) roots. The T5-95 nodules are similar to wild type in ultrastructure, but the T8-1 nodules are different in that the bacteroids are not released from the infection thread. After initial accumulation to relatively high concentration, starch was depleted during nitrogen fixation in fix+ nodules. However, in fix− nodules, the accumulated starch was not metabolized. The activity of starch-bound starch synthase (EC 2.4.1.21) declined in fix+ nodules but remained high in fix− nodules. The activity of α-amylase (EC 3.2.1.1) was only slightly higher than wild type in T5-95 but was four times higher than wild type in T8-1 nodules. The activity of starch phosphorylase (EC 2.4.1.1) increased in all nodule types from 14 to 21 days postinfection. A positive correlation was observed between the capacity of nodules to fix N2 and their capacity to degrade starch. Collectively, these results support the concept that starch accumulated during early stages of nodule development is metabolized to supply energy for nitrogen fixation and to meet the metabolic demands of bacteroids. Key words: nitrogen fixation, starch content, effective and ineffective nodules, starch synthase, starch phosphorylase, α-amylase.

Ineffectiveness of viomycin-resistant mutants of Rhizobium meliloti

1969 ◽  
Vol 15 (7) ◽  
pp. 671-675 ◽  
Author(s):  
G. S. Hendry ◽  
D. C. Jordan
Keyword(s):  
Cell Wall ◽  
Nitrogen Fixation ◽  
Parent Strain ◽  
Rhizobium Meliloti ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Effective Strain ◽  
One Step ◽  
Increased Sensitivity ◽  
Resistant Mutants

Under clearly defined conditions one-step acquisition of viomycin resistance by a normally effective strain of Rhizobium meliloti resulted in one-step acquisition of ineffectiveness in nitrogen fixation, which probably occurred with a one-gene change in the R. meliloti genome. Two-step mutants retained their ability to produce root nodules but such nodules also were ineffective. Increased sensitivity of the viomycin-resistant mutants to glycine and D-alanine was not noted. Bacteroids were not seen in nodules formed by the viomycin-resistant mutants on their homologous host plant. Nitrogenase activity was not detected, by acetylene reduction, in detached ineffective nodules, whereas effective nodules formed 10.6 μmoles of ethylene per hour per gram of nodules. Growth of the effective parent strain in a low concentration of viomycin resulted in elongation and swelling of the cells so that they appeared as artificially produced bacteroids. Viomycin-resistant mutants did not undergo this transformation. Antigens could be readily extracted by hot- and cold-saline extraction of wet packed cells of both resistant and sensitive cultures but antigenic differences, which may have indicated cell wall differences, were not noted.

scholarly journals Effects of Engineered Sinorhizobium meliloti on Cytokinin Synthesis and Tolerance of Alfalfa to Extreme Drought Stress

2012 ◽  
Vol 78 (22) ◽  
pp. 8056-8061 ◽  
Author(s):  
Ji Xu ◽  
Xiao-Lin Li ◽  
Li Luo
Keyword(s):  
Nitrogen Fixation ◽  
Drought Stress ◽  
Sinorhizobium Meliloti ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Severe Drought ◽  
Control Strain ◽  
Free Living ◽  
Content Type ◽  
Host Tolerance

ABSTRACTCytokinin is required for the initiation of leguminous nitrogen fixation nodules elicited by rhizobia and the delay of the leaf senescence induced by drought stress. A few free-living rhizobia have been found to produce cytokinin. However, the effects of engineered rhizobia capable of synthesizing cytokinin on host tolerance to abiotic stresses have not yet been described. In this study, two engineeredSinorhizobiumstrains overproducing cytokinin were constructed. The tolerance of inoculated alfalfa plants to severe drought stress was assessed. The engineered strains, which expressed theAgrobacterium iptgene under the control of different promoters, synthesized more zeatins than the control strain under free-living conditions, but their own growth was not affected. After a 4-week inoculation period, the effects of engineered strains on alfalfa growth and nitrogen fixation were similar to those of the control strain under nondrought conditions. After being subjected to severe drought stress, most of the alfalfa plants inoculated with engineered strains survived, and the nitrogenase activity in their root nodules showed no apparent change. A small elevation in zeatin concentration was observed in the leaves of these plants. The expression of antioxidant enzymes increased, and the level of reactive oxygen species decreased correspondingly. Although theiptgene was transcribed in the bacteroids of engineered strains, the level of cytokinin in alfalfa nodules was identical to that of the control. These findings suggest that engineeredSinorhizobiumstrains synthesizing more cytokinin could improve the tolerance of alfalfa to severe drought stress without affecting alfalfa nodulation or nitrogen fixation.

Renodulation and nitrogen fixing potential of Acacia nilotica inoculated with Rhizobium isolates

1993 ◽  
Vol 39 (1) ◽  
pp. 87-91 ◽  
Author(s):  
Banwari Lal ◽  
Sunil Khanna
Keyword(s):  
Nitrogen Fixation ◽  
Dry Matter ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Acacia Nilotica ◽  
Resistance Pattern ◽  
Dry Matter Yield ◽  
Native Population ◽  
Rhizobium Isolate ◽  
Matter Production

Renodulation and nitrogen fixation potential of indigenous and exotic isolates of Rhizobium were studied in a field experiment with Acacia nilotica from July 1990 to June 1991. The inoculum isolates belonged to different serotypes and did not show cross-reaction with the native population of Rhizobium. Nitrogenase activity of root nodules observed at 4-month intervals covering three seasons snowed a decline during winter months, which corresponded with the senescence of the nodules. Maximal renodulation as checked by serotyping and antibiotic resistance pattern was observed with isolate AB 3 followed by AD 4 and USDA 3325. The highest nitrogenase activity was exhibited in plants inoculated with AD 4 at 12 months. Plants inoculated with Rhizobium isolate USDA 3325 showed the highest increase in dry-matter yield at 12 months. Except for AB 3, dual inoculation with Rhizobium isolates and Glomus fasciculatum did not enhance dry matter production as compared with uninoculated controls or single inoculation of either Rhizobium isolate or G. fasciculatum.Key words: Rhizobium, Acacia nilotica, nitrogenase activity, renodulation.

scholarly journals Introduction of H2-Uptake Hydrogenase Genes Into Rhizobial Strains Improves Symbiotic Nitrogen Fixation in Vicia sativa and Lotus corniculatus Forage Legumes

2021 ◽  
Vol 3 ◽  
Author(s):  
Mariana Sotelo ◽  
Ana Claudia Ureta ◽  
Socorro Muñoz ◽  
Juan Sanjuán ◽  
Jorge Monza ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Rhizobium Leguminosarum ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Lotus Corniculatus ◽  
Vicia Sativa ◽  
Uptake Hydrogenase ◽  
Forage Crops ◽  
Mesorhizobium Loti

Biological nitrogen fixation by the Rhizobium-legume symbiosis allows the conversion of atmospheric nitrogen into ammonia within root nodules mediated by the nitrogenase enzyme. Nitrogenase activity results in the evolution of hydrogen as a result of a side reaction intrinsic to the activity of this enzyme. Some rhizobia, and also other nitrogen fixers, induce a NiFe uptake hydrogenase (Hup) to recycle hydrogen produced by nitrogenase, thus improving the efficiency of the nitrogen fixation process. In this work we report the generation and symbiotic behavior of hydrogenase-positive Rhizobium leguminosarum and Mesorhizobium loti strains effective in vetch (Vicia sativa) and birsfoot trefoil (Lotus corniculatus) forage crops, respectively. The ability of hydrogen recycling was transferred to these strains through the incorporation of hup minitransposon TnHB100, thus leading to full recycling of hydrogen in nodules. Inoculation of Vicia and Lotus plants with these engineered strains led to significant increases in the levels of nitrogen incorporated into the host legumes. The level of improvement of symbiotic performance was dependent on the recipient strain and also on the legume host. These results indicate that hydrogen recycling has the potential to improve symbiotic nitrogen fixation in forage plants.

scholarly journals Isolation and Selection of Rhizobium Tolerant to Pesticides and Aluminum from Acid Soils in Indonesia

2013 ◽  
Vol 16 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Erni Martani ◽  
Sebastian Margino ◽  
Didiek Indradewa ◽  
Agus Supriyo
Keyword(s):  
Ph Value ◽  
Soil Analysis ◽  
Root Nodules ◽  
Acid Soil ◽  
Acid Soils ◽  
Soybean Plant ◽  
High Concentration ◽  
Diffusion Technique ◽  
Wide Range ◽  
Selection Of

Application of Rhizobium as inoculum in acid soil requires specific characters, namely high tolerance to pesticide residues, soil acidity, and high concentration of Aluminum. This study was conducted to isolate Rhizobium having these characters. Inspite of acid soils from Kalimantan, Sumatra, Sulawesi and Java; root nodules of legumes planted in those regions were used as source of isolates. Rhizobial isolation was done using direct isolation andenrichment technique. A paper disc diffusion technique was used in selecting tolerance to pesticides. The selected isolates were examined the tolerance to pH, Al, and ability to form root nodule with soybean. From soil analysis, it could be seen the correlation between pH value and Al concentration. It means that the lower pH value the higher Al concentration. The number of Rhizobium isolates and its tolerance to paraquat was depended on soil type. From 173 strains of isolated Rhizobium, 24 strains were tolerance to pesticides and Aluminum. They were able to grow in wide range of pH, namely 3 – 8, or some of them in 5 - 8. Around 92% of the selected bacteria could form root nodules with soybean plant in different number and size. Hopefully, these isolates can be applied in the pesticide polluted agricultural lands, especially in acid soils with high concentration of Al, and it can also increase soybean production.Keywords: Acid soils, aluminium, Rhizobium, pesticides

scholarly journals MtMOT1.2 is responsible for molybdate supply toMedicago truncatulanodules

2018 ◽  
Author(s):  
Patricia Gil-Díez ◽  
Manuel Tejada-Jiménez ◽  
Javier León-Mediavilla ◽  
Jiangqi Wen ◽  
Kirankumar S. Mysore ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Reductase Activity ◽  
Root Nodules ◽  
Loss Of Function ◽  
Intracellular Membrane ◽  
Wild Type ◽  
Endodermal Cells ◽  
Iron Molybdenum Cofactor

ABSTRACTSymbiotic nitrogen fixation in legume root nodules requires a steady supply of molybdenum for synthesis of the iron-molybdenum cofactor of nitrogenase. This nutrient has to be provided by the host plant from the soil, crossing several symplastically disconnected compartments through molybdate transporters, including members of the MOT1 family. MtMOT1.2 is aMedicago truncatulaMOT1 family member located in the endodermal cells in roots and nodules. Immunolocalization of a tagged MtMOT1.2 indicates that it is associated to the plasma membrane and to intracellular membrane systems, where it would be transporting molybdate towards the cytosol, as indicated in yeast transport assays. A loss-of-functionmot1.2-1mutant showed reduced growth compared to wild-type plants when nitrogen fixation was required, but not when nitrogen was provided as nitrate. While no effect on molybdenum-dependent nitrate reductase activity was observed, nitrogenase activity was severely affected, explaining the observed difference of growth depending on nitrogen source. This phenotype was the result of molybdate not reaching the nitrogen-fixing nodules, since genetic complementation with a wild-typeMtMOT1.2gene or molybdate-fortification of the nutrient solution, both restored wild-type levels of growth and nitrogenase activity. These results support a model in which MtMOT1.2 would mediate molybdate delivery by the vasculature into the nodules.

Nitrogen Fixation by Native Australian Legumes

1981 ◽  
Vol 29 (2) ◽  
pp. 143 ◽  
Author(s):  
AC Lawrie
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Sand Dune ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Sand Dunes ◽  
Late Summer ◽  
Open Forest ◽  
Seasonal And Diurnal Variations ◽  
Major Factors

Nitrogen fixation was studied by the acetylene-reduction technique in root nodules of 10 native Australian legumes in three habitats in Victoria: low open-forest. sandy heathland and coastal sand dunes. Nodular activity reached a maximum in spring (and in autumn in sand-dune species), declined to a minimum in late summer and continued at a low level throughout winter. Mean nitrogenase activity was 1.73 μmol C2H2 reduced g-1 fresh wt nodules h-1, with spring maxima 8-250 times summer minima. It is suggested that variations in rainfall and temperature were the major factors influencing seasonal variations in nodular activity. Estiniates of minimum acetylene reduction per hectare per year were derived from measurements of seasonal and diurnal variations in acetylene reduction and abundance of nodules per hectare, and were used to derive approximate minimum values for nitrogen fixation of 0.004-0.746 kg ha-1 yr-1. The quantities of nitrogen fixed are compared with other reports and the significance of nitrogen fixation by these native legumes is discussed.

scholarly journals Isolation and Enumeration of Bradyrhizobium Species Dwelling In the Root Nodules of Soybean Plant

2020 ◽  
pp. 17-25
Author(s):  
Ishaq Z. ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Root Nodule ◽  
Low Cost ◽  
Root Nodules ◽  
Selective Medium ◽  
Soybean Plant ◽  
Plant Infection ◽  
Soybean Plants ◽  
Biological Nitrogen

Biological Nitrogen fixation is one of the important aspects of organic agriculture gaining considerable attention globally. Information about the number of viable indigenous Bradyrhizobia in soils planted with legumes and their capacity to nodulate is a valuable tool in developing strategies to improve biological nitrogen fixation. Such strategies could potentially lead to increased soybean yields at low cost. This study was conducted to isolate and enumerate Bradyrizobium species dwelling in the root nodule of soybean plant using Bradyrhizobium japonicum selective medium (BJSM). Twenty (20) strains of Bradyrizobium species were isolated from the root nodules of soybean plants harvested from Ahmadu Bello University farm site, located at Bomo district of Sabongari local government area, Kaduna State, Nigeria. This was achieved using the streak method of isolation on BJSM. Ninety percent (18) of these isolates were confirmed as Bradyrizobium species using the plant infection test as they were able to nodulate the roots of soybean plants. The enumeration of the indigenous Bradyrizobium species gave a count ranging from 2.07x105 - 4.0x106 CFU/mL. Thus, the number of Bradyrhizobia obtained in the soil of this study is sufficient to achieve satisfactory results on nodulation and nitrogen fixation. Key words: Soybean, Bradyrhizobium species, Nodulation, Nitrogen fixation

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