scholarly journals Excess nitrate induces nodule greening and reduces transcript and protein expression levels of soybean leghaemoglobins

2020 ◽  
Vol 126 (1) ◽  
pp. 61-72
Author(s):  
Mengke Du ◽  
Zhi Gao ◽  
Xinxin Li ◽  
Hong Liao
Keyword(s):  
Nitrogenase Activity ◽  
Expression Patterns ◽  
Bioinformatic Analysis ◽  
Nodule Development ◽  
Nodule Formation ◽  
N Availability ◽  
Soybean Plants ◽  
Systematic Identification ◽  
Biological Nitrogen ◽  
Soybean Nodulation

Abstract Background and Aims Efficient biological nitrogen fixation (BNF) requires leghaemoglobin (Lb) to modulate oxygen pressure in nodules. Excess N supply severely inhibits BNF through effects on Lb during nodulation. As yet, a systematic identification and characterization of Lb-encoding genes in soybean has not been reported. Methods The effects of N on BNF were studied in soybean plants inoculated with rhizobia and exposed to excess or low N availability in hydroponic cultures. To identify soybean Lb proteins, BLAST searches were performed on the Phytozome website. Bioinformatic analysis of identified GmLbs was then carried out to investigate gene structure, protein homology and phylogenetic relationships. Finally, quantitative real-time PCR was employed to analyse the expression patterns of soybean Lb genes in various tissues and in response to high N availability. Key Results Excess N significantly accelerated nodule senescence and the production of green Lb in nodules. In total, seven haemoglobin (Hb) genes were identified from the soybean genome, with these Hb genes readily split into two distinct clades containing predominantly symbiosis-associated or non-symbiotic Hb members. Expression analysis revealed that all of the symbiosis-associated Lbs except GmLb5 were specifically expressed in nodules, while the non-symbiotic GmHbs, GmHb1 and GmHb2, were predominantly expressed in leaves and roots, respectively. Among identified GmLbs, GmLb1–4 are the major Lb genes acting in soybean nodulation, and each one is also significantly suppressed by exposure to excess N. Conclusions Taken together, the results show that excess N inhibits BNF by reducing nodule formation, Lb concentration and nitrogenase activity. The characteristics of the entire Hb family were analysed, and we found that GmLb1–4 are closely associated with nodule development and N2 fixation. This works forms the basis for further investigations of the role of Lbs in soybean nodulation.

scholarly journals Chickpea shows genotype-specific nodulation responses across soil nitrogen environment and root disease resistance categories

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Krista L. Plett ◽  
Sean L. Bithell ◽  
Adrian Dando ◽  
Jonathan M. Plett
Keyword(s):  
Nitrogen Fixation ◽  
Disease Resistance ◽  
Soil Nitrogen ◽  
Cellular Localization ◽  
Expression Patterns ◽  
Nodule Development ◽  
Nodule Formation ◽  
Symbiotic Relationship ◽  
Plant Genotype ◽  
Factors Affecting

Abstract Background The ability of chickpea to obtain sufficient nitrogen via its symbiotic relationship with Mesorhizobium ciceri is of critical importance in supporting growth and grain production. A number of factors can affect this symbiotic relationship including abiotic conditions, plant genotype, and disruptions to host signalling/perception networks. In order to support improved nodule formation in chickpea, we investigated how plant genotype and soil nutrient availability affect chickpea nodule formation and nitrogen fixation. Further, using transcriptomic profiling, we sought to identify gene expression patterns that characterize highly nodulated genotypes. Results A study involving six chickpea varieties demonstrated large genotype by soil nitrogen interaction effects on nodulation and further identified agronomic traits of genotypes (such as shoot weight) associated with high nodulation. We broadened our scope to consider 29 varieties and breeding lines to examine the relationship between soilborne disease resistance and the number of nodules developed and real-time nitrogen fixation. Results of this larger study supported the earlier genotype specific findings, however, disease resistance did not explain differences in nodulation across genotypes. Transcriptional profiling of six chickpea genotypes indicates that genes associated with signalling, N transport and cellular localization, as opposed to genes associated with the classical nodulation pathway, are more likely to predict whether a given genotype will exhibit high levels of nodule formation. Conclusions This research identified a number of key abiotic and genetic factors affecting chickpea nodule development and nitrogen fixation. These findings indicate that an improved understanding of genotype-specific factors affecting chickpea nodule induction and function are key research areas necessary to improving the benefits of rhizobial symbiosis in chickpea.

scholarly journals A Convenient, Soil-Free Method for the Production of Root Nodules in Soybean to Study the Effects of Exogenous Additives

2018 ◽  
Author(s):  
Swarup Roy Choudhury ◽  
Sarah M. Johns ◽  
Sona Pandey
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Root Nodules ◽  
Growth Conditions ◽  
Nodule Development ◽  
Nodule Formation ◽  
Legume Crop ◽  
Simple Protocol ◽  
Biological Nitrogen

Legumes develop root nodules that harbour endosymbiotic bacteria, rhizobia. These rhizobia convert nitrogen to ammonia by biological nitrogen fixation. A thorough understanding of the biological nitrogen fixation in legumes and its regulation is key to develop sustainable agriculture. It is well known that plant hormones affect nodule formation; however, most studies are limited to model legumes due to their suitability for in vitro, plate-based assays. Specifically, it is almost impossible to measure the effects of exogenous hormones or other additives during nodule development in crop legumes such as soybean as they have huge root system in soil. To circumvent this issue, the present research develops suitable media and growth conditions for efficient nodule development under in vitro, soil free conditions in an important legume crop, soybean. Moreover, we also evaluate the effects of all major phytohormones during soybean nodulation under identical conditions. This versatile, inexpensive, scalable and simple protocol provides several advantages over previously established methods. It is extremely time-and resource-efficient, does not require special training or equipment, and produces highly reproducible results. The approach is expandable to other large legumes as well as for other exogenous additives.

scholarly journals Soil humidity as a productive conditioner of soybean culture through inoculation, co-inoculation and rooting

2020 ◽  
pp. 932-939
Author(s):  
Evandro Ademir Deak ◽  
Thomas Newton Martin ◽  
Glauber Monçon Fipke ◽  
Jessica Deolinda Leivas Stecca ◽  
Vinícius dos Santos Cunha
Keyword(s):  
Azospirillum Brasilense ◽  
Dry Mass ◽  
Sowing Dates ◽  
Soybean Plants ◽  
The Times ◽  
The Many ◽  
High Yields ◽  
Biological Nitrogen ◽  
Measured Water ◽  
Soybean Nodulation

In the soybean crop, the practice of inoculation is crucial for producing high yields. This is because biological nitrogen fixation (BNF) is the main supplier of the nutrient demand for this crop. However, a few environmental variables can also greatly influence the survival of the bacteria that control this process. In this context, the present work was performed to confirm the many ways in which soil moisture affects this process. In the field, we conducted two experiments at the times of the two sowing dates, 11/24/2015 and 12/17/2015, adopting the factorial 7 x 2 design, with four replications. The inoculation treatments included, non-inoculated (NI); not inoculated along with the nitrogen supplied at the 200 kg ha-1 (NI+N) dosage; inoculation with Bradyrhizobium [I (Brady)]; root enhancers (R); inoculation with Bradyrhizobium + root enhancers (I+R); co-inoculation with Bradyrhizobium + Azospirillum brasilense (I+Azo); co-inoculation with Bradyrhizobium + Azospirillum brasilense + root enhancers (I+Azo+R). The second factor included was the use or absence of a water jet (200 L ha-1) directed onto the seeds in the sowing furrow. Then estimations of the initial establishment of the plants, nodulation, and productivity components were measured. Water supplied to the sowing furrow had no effect on soybean nodulation and yield components. Co-inoculation promoted nodulation in soybean plants, particularly in dry mass of the nodules and number of nodules per plant.

Host–endophyte interactions in effective and ineffective nodules induced by the endophyte of Myrica gale

1983 ◽  
Vol 61 (11) ◽  
pp. 2898-2909 ◽  
Author(s):  
Kathryn A. VandenBosch ◽  
John G. Torrey
Keyword(s):  
Nitrogenase Activity ◽  
Root Nodules ◽  
Seedling Development ◽  
Nodule Development ◽  
Nodule Formation ◽  
Cortical Tissue ◽  
Intercellular Spaces ◽  
Cortical Cells ◽  
Myrica Gale ◽  
Infected Cells

Suspensions of crushed root nodules of Myrica gale containing the actinomycete Frankia induced nodule formation on roots of seedlings of M. gale and Comptonia peregrina grown in nutrient water culture. Nodules formed on M. gale were normal in structure and exhibited nitrogenase activity (measured as acetylene reduction) and provided the necessary nitrogen for seedling development. These effective nodules showed typical external and internal structure with the endophyte developing both vesicles and sporangia within cortical cells of the host tissue. Small nodules formed on C. peregrina representing the primary nodule stage. They lacked nitrogenase activity and were termed ineffective. Vesicles failed to develop within these ineffective nodules. However, sporangia were formed in infected cells and within intercellular spaces of the nodule cortical tissue. In addition, prominent amyloplasts occurred in infected cells of the ineffective nodules, a feature lacking in effective nodules. Exogenously supplied combined nitrogen increased seedling growth but did not improve nodule development or endophyte morphogenesis in the ineffective nodules.

Sequence analysis and expression patterns of two nifA genes from Frankia EuIK1

2001 ◽  
Vol 28 (9) ◽  
pp. 939
Author(s):  
Hyoungseok Lee ◽  
Si Bum Sung ◽  
Ho Bang Kim ◽  
Chung Sun An
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Nitrogenase Activity ◽  
Sequence Similarity ◽  
Expression Patterns ◽  
Amino Acid Sequences ◽  
Start Codon ◽  
Nodule Development ◽  
Intergenic Sequence ◽  
Elaeagnus Umbellata

This paper originates from an address at the 8th International Symposium on Nitrogen Fixation with Non-Legumes, Sydney, NSW, December 2000 Two nifA genes were cloned from Frankia EuIK1 strain, a symbiont of Elaeagnus umbellata Thunb. and analysed on the basis of their deduced amino acid sequences and expression patterns. The complete nucleotide sequence of 1926 bp of nifA1 and 1524 bp of nifA2 was determined, respectively. A putative NifA-binding site was found –95 to about –80 bp upstream of start codon for nifA1 ORF as TGT-N10-ACA, but the clpB ORF was followed by nifA2 ORF with 15 bp of intergenic sequence. Deduced amino acid sequence showed that two nifA genes encode typical NifA, having three major domains and two linkers, and their central domains of NifA1 and NifA2 showed sequence similarity of 70–75% with those from other NifA proteins. However, entire NifA2 ORF is more similar to alternative NifA (60%) than to typical NifA (53%). Conserved amino acid sequence in helix-turn-helix motif of typical NifA was also found in NifA1, but it was not conserved in NifA2, which is also common in alternative NifA proteins. Moreover, the expression of nifA1 during nodule development was similar to that of Rhizobium meliloti in that it was expressed at low level constitutively, while that of nifA2 was similar to the pattern of nifH, structural gene for nitrogenase reductase, in that its transcripts level was changed in accordance with nitrogenase activity. These results indicate that nifA1 and nifA2 might be classified into typical nifA and alternative nifA, respectively. This is the first report on the presence of two nifA genes in Frankia.

scholarly journals Isolation and evaluation of endophytic bacteria from root nodules of Glycine max L. (Merr.) and their potential use as biofertilizers

2019 ◽  
Vol 17 (3) ◽  
pp. e1103
Author(s):  
Arely A. Vargas-Díaz ◽  
Ronald Ferrera-Cerrato ◽  
Hilda V. Silva-Rojas ◽  
Alejandro Alarcón
Keyword(s):  
Endophytic Bacteria ◽  
Biochemical Characterization ◽  
Cropping Systems ◽  
Root Nodules ◽  
Nodule Development ◽  
Nodule Formation ◽  
N Fixation ◽  
Tropical Regions ◽  
Bradyrhizobium Sp ◽  
Soybean Plants

Aim of study: To isolate and characterize endophytic bacteria inhabiting soybean root nodules collected from two tropical cropping systems in Mexico, and to evaluate the bacterial effects in soybean plants under controlled conditions.Area of study: The study was carried out at two locations (San Antonio Cayal and Nuevo Progreso municipalities) of Campeche State, Mexico.Material and methods: Two experimental stages were performed: 1) isolation, morphological and biochemical characterization, and molecular identification of endophytic bacteria from root-nodules of four soybean varieties grown at field conditions; and 2) evaluation of the effects of endophytic isolates on soybean growth and nodule development, and the effects of bacterial co-inoculation on soybean plants, under controlled conditions.Main results: Twenty-three endophytic bacteria were isolated from root nodules, and identified as Agrobacterium, Bradyrhizobium, Rhizobium, Ensifer, Massilia, Chryseobacterium, Enterobacter, Microbacterium, Serratia, and Xanthomonas. Under controlled conditions, Rhizobium sp. CPO4.13C or Agrobacterium tumefaciens CPO4.15C significantly increased the plant height (46% and 41%, respectively), whereas Bradyrhizobium sp. CPO4.24C promoted the nodule formation (36 nodules/plant). The co-inoculation of B. japonicum USDA110 and Bradyrhizobium sp. CPO4.24C enhanced plant growth, height (33.87 cm), root nodulation (69 nodules/plant) and N-fixation (3.10 µmol C2H4 h-1 plant-1) in comparison to the negative control.Research highlights:  Results suggest that the native Bradyrhizobium sp. CPO4.24C may be used as a biofertilizer directed to developing sustainable soybean cropping at tropical regions.

Effects of a Nod-factor-overproducing strain of Sinorhizobium meliloti on the expression of the ENOD40 gene in Melilotus alba

2002 ◽  
Vol 80 (9) ◽  
pp. 907-915 ◽  
Author(s):  
Walter F Giordano ◽  
Michelle R Lum ◽  
Ann M Hirsch
Keyword(s):  
Lateral Root ◽  
Sinorhizobium Meliloti ◽  
Cortical Cell ◽  
Host Cells ◽  
Nodule Development ◽  
Nodule Formation ◽  
Additional Increase ◽  
Nod Factor ◽  
Melilotus Alba ◽  
Different Strains

We have initiated studies on the molecular biology and genetics of white sweetclover (Melilotus alba Desr.) and its responses to inoculation with the nitrogen-fixing symbiont Sinorhizobium meliloti. Early nodulin genes such as ENOD40 serve as markers for the transition from root to nodule development even before visible stages of nodule formation are evident. Using Northern blot analysis, we found that the ENOD40 gene was expressed within 6 h after inoculation with two different strains of S. meliloti, one of which overproduces symbiotic Nod factors. Inoculation with this strain resulted in an additional increase in ENOD40 gene expression over a typical wild-type S. meliloti strain. Moreover, the increase in mRNA brought about by the Nod-factor-overproducing strain 24 h after inoculation was correlated with lateral root formation by using whole-mount in situ hybridization to localize ENOD40 transcripts in lateral root meristems and by counting lateral root initiation sites. Cortical cell divisions were not detected. We also found that nodulation occurred more rapidly on white sweetclover in response to the Nod-factor-overproducing strain, but ultimately there was no difference in nodulation efficiency in terms of nodule number or the number of roots nodulated by the two strains. Also, the two strains could effectively co-colonize the host when inoculated together, although a few host cells were occupied by both strains.Key words: ENOD40, Nod factor, Melilotus, Sinorhizobium, symbiosis.

scholarly journals Effects of nitrogen concentrations on nodulation and nitrogenase activity in dual root systems of soybean plants

2017 ◽  
Vol 63 (5) ◽  
pp. 470-482 ◽  
Author(s):  
Xuan Xia ◽  
Chunmei Ma ◽  
Shoukun Dong ◽  
Yao Xu ◽  
Zhenping Gong
Keyword(s):  
Nitrogenase Activity ◽  
Root Systems ◽  
Nitrogen Concentrations ◽  
Soybean Plants

scholarly journals Glix 13, a New Drug Acting on Glutamatergic Pathways in Children and Animal Models of Autism Spectrum Disorders

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Annamaria Chiara Santini ◽  
Giovanna Maria Pierantoni ◽  
Raffaele Gerlini ◽  
Rosamaria Iorio ◽  
Yinka Olabinjo ◽  
...  
Keyword(s):  
Nmda Receptor ◽  
Partial Agonist ◽  
Receptor Gene ◽  
Expression Patterns ◽  
Bioinformatic Analysis ◽  
Autism Spectrum ◽  
Receptor Modulator ◽  
Therapeutic Procedures ◽  
Significant Enrichment ◽  
Glutamatergic Pathways

Recently standardized diagnostic instruments have been developed in diagnostic and therapeutic procedures for Autism Spectrumv Disorders (ASD). According to the DSM-5 criteria, individuals with ASD must show symptoms from early childhood. These symptoms are communication deficits and restricted, repetitive patterns of behaviour. It was recently described by Bioinformatic analysis that 99 modified genes were associated with human autism. Gene expression patterns in the low-line animals show significant enrichment in autism-associated genes and the NMDA receptor gene family was identified among these. Using ultrasonic vocalizations, it was demonstrated that genetic variation has a direct impact on the expression of social interactions. It has been proposed that specific alleles interact with a social reward process in the adolescent mouse modifying their social interaction and their approach toward each other. In this review we report that the monoclonal antibody-derived tetrapeptide GLYX-13 was found to act as an N-methyl-D-aspartate receptor modulator and possesses the ability to readily cross the blood brain barrier. Treatment with the NMDAR glycine site partial agonist GLYX-13 rescued the deficit in the animal model. Thus, the NMDA receptor has been shown to play a functional role in autism, and GLYX-13 shows promise for the treatment of autism in autistic children.

scholarly journals Potential of Phototrophic Purple Nonsulfur Bacteria to Fix Nitrogen in Rice Fields

2021 ◽  
Vol 10 (1) ◽  
pp. 28
Author(s):  
Isamu Maeda
Keyword(s):  
Nitrogen Fixation ◽  
Regulatory Networks ◽  
Nitrogenase Activity ◽  
Field Studies ◽  
Rice Fields ◽  
Purple Nonsulfur Bacteria ◽  
Available Nitrogen ◽  
Nitrogenase Activities ◽  
Plant Available Nitrogen ◽  
Biological Nitrogen

Biological nitrogen fixation catalyzed by Mo-nitrogenase of symbiotic diazotrophs has attracted interest because its potential to supply plant-available nitrogen offers an alternative way of using chemical fertilizers for sustainable agriculture. Phototrophic purple nonsulfur bacteria (PNSB) diazotrophically grow under light anaerobic conditions and can be isolated from photic and microaerobic zones of rice fields. Therefore, PNSB as asymbiotic diazotrophs contribute to nitrogen fixation in rice fields. An attempt to measure nitrogen in the oxidized surface layer of paddy soil estimates that approximately 6–8 kg N/ha/year might be accumulated by phototrophic microorganisms. Species of PNSB possess one of or both alternative nitrogenases, V-nitrogenase and Fe-nitrogenase, which are found in asymbiotic diazotrophs, in addition to Mo-nitrogenase. The regulatory networks control nitrogenase activity in response to ammonium, molecular oxygen, and light irradiation. Laboratory and field studies have revealed effectiveness of PNSB inoculation to rice cultures on increases of nitrogen gain, plant growth, and/or grain yield. In this review, properties of the nitrogenase isozymes and regulation of nitrogenase activities in PNSB are described, and research challenges and potential of PNSB inoculation to rice cultures are discussed from a viewpoint of their applications as nitrogen biofertilizer.

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