scholarly journals Localization, Gene Expression, and Functions of Glutamine Synthetase Isozymes in Wheat Grain (Triticum aestivum L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Yihao Wei ◽  
Shuping Xiong ◽  
Zhiyong Zhang ◽  
Xiaodan Meng ◽  
Lulu Wang ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Metabolism ◽  
Glutamate Synthase ◽  
Grain Filling ◽  
Maximum Activity ◽  
Transfer Cells ◽  
Aleurone Layer ◽  
Wheat Grain ◽  
Plant Nitrogen ◽  
Endosperm Transfer Cells

Glutamine synthetase (GS) plays a major role in plant nitrogen metabolism, but the roles of individual GS isoforms in grains are unknown. Here, the localization and expression of individual TaGS isozymes in wheat grain were probed with TaGS isoenzyme-specific antibodies, and the nitrogen metabolism of grain during the grain filling stage were investigated. Immunofluorescence revealed that TaGS1;1, TaGS1;3, and TaGS2 were expressed in different regions of the embryo. In grain transporting tissues, TaGS1;2 was localized in vascular bundle; TaGS1;2 and TaGS1;1 were in chalaza and placentochalaza; TaGS1;1 and TaGS1;3 were in endosperm transfer cells; and TaGS1;3 and TaGS2 were in aleurone layer. GS exhibited maximum activity and expression at 8 days after flowering (DAF) with peak glutamine content in grains; from then, NH4+ increased largely from NO3- reduction, glutamate dehydrogenase (GDH) aminating activity increased continuously, and the activities of GS and glutamate synthase (GOGAT) decreased, while only TaGS1;3 kept a stable expression in different TaGS isozymes. Hence, GS-GOGAT cycle and GDH play different roles in NH4+ assimilation of grain in different stages of grain development; TaGS1;3, located in aleurone layer and endosperm transfer cells, plays a key role in Gln into endosperm for gluten synthesis. At 30 DAF, grain amino acids are mainly transported from maternal phloem.

scholarly journals Elucidation of the role of glutamine synthetase seed isoform GLN1;5 in Arabidopsis thaliana (L.) with a reverse genetics approach

2019 ◽  
Vol 71 (3) ◽  
pp. 443-453
Author(s):  
Milan Dragicevic ◽  
Katarina Cukovic ◽  
Snezana Zdravkovic-Korac ◽  
Ana Simonovic ◽  
Milica Bogdanovic ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Glutamine Synthetase ◽  
Reverse Genetics ◽  
Technological Development ◽  
Expression Patterns ◽  
Dry Weight ◽  
Grain Filling ◽  
Kinetic Properties ◽  
Plant Nitrogen

Glutamine synthetase (E.C. 6.3.1.2) is a key enzyme of plant nitrogen metabolism that assimilates ammonia into glutamine. The Arabidopsis thaliana genome encodes one chloroplastic (GLN2) and five cytosolic (GLN1;1 ? GLN1;5) isoforms with different expression patterns, kinetic properties, regulation and functions. Physiological roles of different isoforms have been elucidated mainly by studying knockout mutants. However, the role of GLN1;5, which is expressed in dry seeds, remains unknown. To clarifty the function of GLN1;5, we studied a GLN1;5 knockout line (GLN1;5KO) homozygous for T-DNA insertion within the GLN1;5. GLN1;5 deficiency results in a phenotype with slightly delayed bolting and fewer siliques. The dry weight of GLN1;5KO seeds was 73.3% of wild-type (WT) seed weight, with seed length 90.9% of WT seeds. Finally, only 18.33% of the mutant seeds germinated in water within 10 days in comparison to 34.67% of WT seeds. KNO3 strongly stimulated germination of both GLN1;5KO and WT seeds, while germination in the presence of increasing NH4Cl concentrations potentiated the differences between the two genotypes. It can be concluded that GLN1;5 activity supports silique development and grain filling and that it has a role in ammonium reassimilation in the seed, as well as assimilation and/or detoxification of ammonium from the environment. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON173024 and Grant no. ON173015]

scholarly journals A New Perspective on the Role of Glutamine Synthetase in Nitrogen Remobilization in Wheat (Triticum aestivum L.)

2021 ◽  
Vol 22 (20) ◽  
pp. 11083
Author(s):  
Yihao Wei ◽  
Lulu Wang ◽  
Butan Qin ◽  
Huiqiang Li ◽  
Xiaoran Wang ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Vascular System ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Nitrogen Remobilization ◽  
Plant Nitrogen ◽  
Key Enzyme ◽  
N Remobilization ◽  
New Perspective ◽  
Ureide Degradation

Glutamine synthetase (GS), a key enzyme in plant nitrogen metabolism, is closely related to nitrogen remobilization. However, how GS isoforms participate in nitrogen remobilization remains unclear. Here, the spatiotemporal expression of the TaGS gene family after anthesis was investigated, and the results showed that TaGS1;1 was mainly encoded by TaGS1;1-6A, while the other isozymes were mainly encoded by TaGS localized on the A and D subgenomes. TaGS1;2-4A/4D had the highest expression level, especially in rachis and peduncle. Furthermore, immunofluorescence showed TaGS1;2 was located in the phloem of rachis and peduncle. GUS (β-glucuronidase) staining confirmed that ProTaGS1;2-4A/4D::GUS activity was mainly present in the vascular system of leaves, roots, and petal of Arabidopsis. Ureides, an important transport form of nitrogen, were mainly synthesized in flag leaves and transported to grains through the phloem of peduncle and rachis during grain filling. TaAAH, which encodes the enzyme that degrades ureides to release NH4+, had a higher expression in rachis and peduncle and was synchronized with the increase in NH4+ concentration in phloem, indicating that NH4+ in phloem is from ureide degradation. Taking the above into account, TaGS1;2, which is highly expressed in the phloem of peduncle and rachis, may participate in N remobilization by assimilating NH4+ released from ureide degradation.

Enzymes of Nitrogen Metabolism in Legume Nodules: a Comparative Study

1978 ◽  
Vol 5 (5) ◽  
pp. 553 ◽  
Author(s):  
MJ Boland ◽  
HM Fordyce ◽  
RM Greenwood
Keyword(s):  
Glutamine Synthetase ◽  
Comparative Study ◽  
Glutamate Dehydrogenase ◽  
Nitrogen Metabolism ◽  
Glutamate Synthase ◽  
Ammonia Assimilation ◽  
Legume Species

Levels of activity of glutamine synthetase, glutamate dehydrogenase and NADH-dependent glutamate synthase in nodule cytoplasm extracts of twelve herbaceous legume species have been measured. Nodules of all species contained substantial quantities of glutamine synthetase. Levels of glutamate synthase were found to be between 7 and 100% of those of glutamine synthetase, while levels of glutamate dehydrogenase varied widely between 0.2 and 150% of those of glutamine synthetase. The estimated Km for hydroxylamine of glutamine synthetase was found to vary between 0.02 and 0.5 mM in nine species tested, while that of glutamate dehydrogenase for ammonia varied between 0.03 M and 0.1 M in the four species containing significant levels of that enzyme. It is proposed that the pathway of ammonia assimilation via glutamine synthetase and NADH-dependent glutamate synthase-catalysed reactions is universal in legume nodule metabolism.

scholarly journals Genome Wide Analysis of the Transcriptional Profiles in Different Regions of the Developing Rice Grains

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ting-Ying Wu ◽  
Marlen Müller ◽  
Wilhelm Gruissem ◽  
Navreet K. Bhullar
Keyword(s):  
Gene Expression ◽  
Dna Sequence ◽  
Expression Patterns ◽  
Grain Filling ◽  
Aleurone Layer ◽  
Rice Grain ◽  
Sequence Motifs ◽  
Grain Development ◽  
Spatio Temporal ◽  
Dna Sequence Motifs

Abstract Background Rice is an important food source for humans worldwide. Because of its nutritional and agricultural significance, a number of studies addressed various aspects of rice grain development and grain filling. Nevertheless, the molecular processes underlying grain filling and development, and in particular the contributions of different grain tissues to these processes, are not understood. Main Text Using RNA-sequencing, we profiled gene expression activity in grain tissues comprised of cross cells (CC), the nucellar epidermis (NE), ovular vascular trace (OVT), endosperm (EN) and the aleurone layer (AL). These tissues were dissected using laser capture microdissection (LCM) at three distinct grain development stages. The mRNA expression datasets offer comprehensive and new insights into the gene expression patterns in different rice grain tissues and their contributions to grain development. Comparative analysis of the different tissues revealed their similar and/or unique functions, as well as the spatio-temporal regulation of common and tissue-specific genes. The expression patterns of genes encoding hormones and transporters indicate an important role of the OVT tissue in metabolite transport during grain development. Gene co-expression network prediction on OVT-specific genes identified several distinct and common development-specific transcription factors. Further analysis of enriched DNA sequence motifs proximal to OVT-specific genes revealed known and novel DNA sequence motifs relevant to rice grain development. Conclusion Together, the dataset of gene expression in rice grain tissues is a novel and useful resource for further work to dissect the molecular and metabolic processes during rice grain development.

scholarly journals Foliar Application of Nitrogen Affects Metabolism and Productivity of Soybean

2021 ◽  
Vol 13 (10) ◽  
pp. 31
Author(s):  
Walquíria F. Teixeira ◽  
Evandro B. Fagan ◽  
Antônio P. M. Machado ◽  
Daniel Fortune ◽  
Fernando R. Moreira
Keyword(s):  
Nitrogen Metabolism ◽  
Photosynthetic Activity ◽  
Slow Release ◽  
Foliar Application ◽  
Reductase Activity ◽  
Urea Formaldehyde ◽  
Grain Filling ◽  
Control Treatment ◽  
Consequent Reduction ◽  
Soybean Plants

Soybean is one of the world’s most economically important crops and several factors can affect the productivity of this culture. Among these factors is the supply of needed nitrogen, especially in the reproductive stage, as it acts in photosynthetic activity and in grain filling. In view of this, the objective of our work was to evaluate the effect of foliar application of nitrogen in different reproductive stages in soybean culture. Two sources of nitrogen were used: conventional urea and urea-formaldehyde/triazone, both applied in reproductive stages R2, R3, R4, or R5, as well as a control treatment without foliar application of nitrogen. Plants submitted to foliar application of urea-formaldehyde/triazone showed an increase in nitrogen metabolism (percentage of nitrogen derived from the atmosphere [Ndfa] and nitrate reductase activity [NR]), an increase in peroxidase (POD), and the consequent reduction in hydrogen peroxide (H2O2) in all stages of application of this treatment. When urea-formaldehyde/triazone was applied in R4, it resulted in a 7% increase in yield. The application of conventional urea in reproductive stages R4 and R5 increased nitrogen metabolism and resulted in an increase in yield by 4%. However, conventional urea reduced yield when applied in stages R2 and R3. The use of low doses of foliar nitrogen in stages R4 and R5, increased nitrogen metabolism in soybean plants. The timing of the application has a direct impact on the results with the slow-release nitrogen (urea formaldehyde /triazone) showing better results when applied in stage R4 and better results for conventional urea in R5.

scholarly journals Phytohormone up-regulates the biochemical constituent, exopolysaccharide and nitrogen metabolism in paddy-field cyanobacteria exposed to chromium stress

2020 ◽  
Author(s):  
Sanjesh Tiwari ◽  
Anuradha Patel ◽  
Sheo Mohan Prasad
Keyword(s):  
Nitrogen Metabolism ◽  
Uptake Rate ◽  
Paddy Field ◽  
Growth Parameter ◽  
Glutamate Synthase ◽  
Nostoc Muscorum ◽  
Biochemical Constituent ◽  
Diazotrophic Cyanobacteria ◽  
Chromium Stress ◽  
Cr Uptake

Abstract Current study deals with the assuaging effects of two phytohormones; indole acetic acid (IAA; 290 nM) and kinetin (KN; 10 nM) on growth, phycobiliproteins, status of nitrogen metabolism and biochemical constituents; protein, carbohydrate and exopolysaccharide contents in two diazotrophic cyanobacteria Nostoc muscorum and Anabaena exposed to chromium (CrVI) stress (100 µM and 150 µM). Chromium individually at both the tested doses expressively declined the growth, chlorophyll a to carotenoid ratio and contents of phycobiliproteins; phycocyanin (PC), allophycocyanin (APC), and phycoerythrin (PE). With distinctive impact on status of nitrogen metabolism chromium significantly reduced the nitrate (NO3—) and nitrite (NO2—) uptake rate and foremost decrease in nitrate and ammonia assimilating enzyme; nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthase (GOGAT) except glutamate dehydrogenase (GDH). However, beneath alike condition, exogenous application of IAA and KN exhibited noteworthy assuaging effects on growth-regulating parameters in both the paddy field cyanobacteria, which consummately occurred as a result of substantial decrease in Cr uptake and inducing signaling responses and also enhances the growth parameter i.e. nitrogen metabolism as a result of considerable lowering in Cr induced damaging effect on nitrogen metabolism and uptake rate, and the alleviating effect was more pronounced with the lower dose of Cr, efficient in N.muscorum than Anabaena.

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