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.

scholarly journals Nitrogen Regulating the Expression and Localization of Four Glutamine Synthetase Isoforms in Wheat (Triticum aestivum L.)

2020 ◽  
Vol 21 (17) ◽  
pp. 6299
Author(s):  
Yihao Wei ◽  
Xiaochun Wang ◽  
Zhiyong Zhang ◽  
Shuping Xiong ◽  
Xiaodan Meng ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Assimilation ◽  
Vascular Tissue ◽  
Mrna Level ◽  
Triticum Aestivum L ◽  
Kinetic Properties ◽  
High Catalytic Activity ◽  
Root Tips ◽  
Plant Nitrogen ◽  
Key Enzyme

Glutamine synthetase (GS), the key enzyme in plant nitrogen assimilation, is strictly regulated at multiple levels, but the most relevant reports focus on the mRNA level. Using specific antibodies as probes, the effects of nitrogen on the expression and localization of individual wheat GS (TaGS) isoforms were studied. In addition to TaGS2, TaGS1;1 with high affinity to substrate and TaGS1;3 with high catalytic activity were also localized in mesophyll, and may participate in cytoplasmic assimilation of ammonium (NH4+) released from photorespiration or absorbed by roots; TaGS1;2 was localized in xylem of leaves. In roots, although there were hundreds of times more TaGS1;1 than TaGS1;2 transcripts, the amount of TaGS1;1 subunit was not higher than that of TaGS1;2; NH4+ inhibited TaGS1;1 expression but stimulated TaGS1;3 expression. In root tips, nitrate stimulated TaGS1;1, TaGS1;3, and TaGS2 expression in meristem, while NH4+ promoted tissue differentiation and TaGS1;2 expression in endodermis and vascular tissue. Only TaGS1;2 was located in vascular tissue of leaves and roots, and was activated by glutamine, suggesting a role in nitrogen transport. TaGS1;3 was induced by NH4+ in root endodermis and mesophyll, suggesting a function in relieving NH4+ toxicity. Thus, TaGS isoforms play distinct roles in nitrogen assimilation for their different kinetic properties, tissue locations, and response to nitrogen regimes.

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 Inferring vascular architecture of the wheat spikelet based on resource allocation in the branched headt (bht-A1) near isogenic lines

2019 ◽  
Vol 46 (11) ◽  
pp. 1023 ◽  
Author(s):  
Gizaw M. Wolde ◽  
Thorsten Schnurbusch
Keyword(s):  
Dry Matter ◽  
Vascular System ◽  
Grain Filling ◽  
Spikelet Fertility ◽  
Dry Matter Accumulation ◽  
Near Isogenic Lines ◽  
Network Systems ◽  
Vascular Architecture ◽  
Isogenic Lines ◽  
Rachis Node

Substantial genetic and physiological efforts were made to understand the causal factors of floral abortion and grain filling problem in wheat. However, the vascular architecture during wheat spikelet development is surprisingly under-researched. We used the branched headt near-isogenic lines, FL-bht-A1-NILs, to visualise the dynamics of spikelet fertility and dry matter accumulation in spikelets sharing the same rachis node (henceforth Primary Spikelet, PSt, and Secondary Spikelet, SSt). The experiment was conducted after grouping FL-bht-A1-NILs into two groups, where tillers were consistently removed from one group. Our results show differential spikelet fertility and dry matter accumulation between the PSt and SSt, but also showed a concomitant improvement after de-tillering. This suggests a tight regulation of assimilate supply and dry matter accumulation in wheat spikelets. Since PSt and SSt share the same rachis node, the main vascular bundle in the rachis/rachilla is expected to bifurcate to connect each spikelet/floret to the vascular system. We postulate that the vascular structure in the wheat spikelet might even follow Murray’s law, where the wide conduits assigned at the base of the spikelet feed the narrower conduits of the distal florets. We discuss our results based on the two modalities of the vascular network systems in plants.

scholarly journals Variation of 13C and 15N enrichments in different plant components of labeled winter wheat (Triticum aestivum L.)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7738
Author(s):  
Zhaoan Sun ◽  
Shuxia Wu ◽  
Biao Zhu ◽  
Yiwen Zhang ◽  
Roland Bol ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
N Fertilization ◽  
Wheat Growth ◽  
Filling Stage ◽  
N Enrichment ◽  
Two Stages ◽  
Grain Filling Stage

Information on the homogeneity and distribution of 13carbon (13C) and nitrogen (15N) labeling in winter wheat (Triticum aestivum L.) is limited. We conducted a dual labeling experiment to evaluate the variability of 13C and 15N enrichment in aboveground parts of labeled winter wheat plants. Labeling with 13C and 15N was performed on non-nitrogen fertilized (−N) and nitrogen fertilized (+N, 250 kg N ha−1) plants at the elongation and grain filling stages. Aboveground parts of wheat were destructively sampled at 28 days after labeling. As winter wheat growth progressed, δ13C values of wheat ears increased significantly, whereas those of leaves and stems decreased significantly. At the elongation stage, N addition tended to reduce the aboveground δ13C values through dilution of C uptake. At the two stages, upper (newly developed) leaves were more highly enriched with 13C compared with that of lower (aged) leaves. Variability between individual wheat plants and among pots at the grain filling stage was smaller than that at the elongation stage, especially for the −N treatment. Compared with those of 13C labeling, differences in 15N excess between aboveground components (leaves and stems) under 15N labeling conditions were much smaller. We conclude that non-N fertilization and labeling at the grain filling stage may produce more uniformly 13C-labeled wheat materials, whereas the materials were more highly 13C-enriched at the elongation stage, although the δ13C values were more variable. The 15N-enriched straw tissues via urea fertilization were more uniformly labeled at the grain filling stage compared with that at the elongation stage.

scholarly journals Leaf photosynthetic function duration during yield formation of large-spike wheat in rainfed cropping systems

2018 ◽  
Author(s):  
Lifang Wang ◽  
Jutao Sun ◽  
Chenyang Wang ◽  
Zhouping Shangguan
Keyword(s):  
Photosynthetic Rate ◽  
Cropping Systems ◽  
Average Rate ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Relative Water ◽  
Large Spike ◽  
Rate Of Decline ◽  
Yield Formation

Improving photosynthetic capacity significantly affects the yield of wheat (Triticum aestivum L.) in rainfed regions. In this study, the physiological characteristics of eight large-spike wheat lines were compared with a multiple-spike cultivar as a control (CK) in a field over two consecutive seasons: 2010–2012. The tillering peak was 7–21 d after returning green for line 2040, the average rate of decline of relative water content was slower, and the average duration time of photosynthetic rate was longer than CK in vitro. There was a strong linear and positive correlation between photosynthetic rate and root activity at jointing, flowering, and grain-filling stages. In addition, average yields were higher in large-spike lines than CK (multiple-spike cultivar). The results suggest that large-spike lines might have greater water retaining capacity during yield formation under rainfed conditions.

scholarly journals Effect of Heat Stress on Inter-relationship of Physiological and Biochemical Traits with Grain Yield in Wheat (Triticum aestivum L.)

2020 ◽  
pp. 19-29
Author(s):  
Amrita Kumari ◽  
R. D. Ranjan ◽  
Chandan Roy ◽  
Awadesh Kumar Pal ◽  
S. Kumar
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Flag Leaf ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Seedling Stage ◽  
Biochemical Traits ◽  
Highly Correlated ◽  
Complex Phenomena ◽  
Physiological And Biochemical

Heat stress, particularly the stress appears at the time of flowering to grain filling stages causing severe yield loss in wheat. Heat tolerance is complex phenomena that include adjustment in morphological, physiological and biochemical traits of the crop. Present investigation was carried out to understand the effect of terminal heat stress on different traits of wheat. The experiment was conducted in three dates of sowing as timely sown, late sown and very late sown to expose the crop to heat stress at later stages of the crop growth. Significant genetic variations for all the traits evaluated under three conditions indicated the presence of variability for the traits. Trait association analysis revealed that flag leaf chlorophyll content and MSI at seedling stage; MDA at reproductive stage had direct relationship with grain yield. While under very late sown condition MDA and RWC at seedling stages were found to be highly correlated with grain yield. It indicates that MDA, RWC at seedling stage and days to booting, days to milking plays important role in very late sown condition that can be used as selection criteria in breeding programme.

scholarly journals Growth and clorophyll content dynamics of winter wheat (Triticum aestivum L.) in different cropyear

2013 ◽  
pp. 101-105
Author(s):  
Enikő Vári
Keyword(s):  
Winter Wheat ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Area Index ◽  
Rotation System ◽  
Crop Rotation System ◽  
Two Parameters ◽  
The University ◽  
The Relationship

The experiments were carried out at the Látókép experimental station of the University of Debrecen on chernozem soil in a long term winter wheat experiment in the season of 2011 and 2012 in triculture (pea-wheat-maize) and biculture (wheat-maize) at three fertilisation levels (control, N50+P35K40, N150+P105K120). Two different cropyears were compared (2011 and 2012). The research focused on the effects of forecrop and fertilisation on the Leaf Area Index, SPAD values and the amount of yield in two different cropyears. We wanted to find out how the examined parameters were affected by the cropyear and what the relationship was between these two parameters and the changes of the amount of yield. Examining the effects of growing doses of fertilizers applied, results showed that yields increased significantly in both rotations until the N150+PK level in 2011 and 2012. By comparing the two years, results show that in 2011 there was a greater difference in yields between the rotations (7742 kg ha-1 at N150+PK in the biculture and 9830 kg ha-1 at N150+PK in the triculture). Though wheat yields following peas were greater in 2012, results equalized later on at N150+PK levels (8109–8203 kg ha-1). Due to the favorable agrotechnical factors, the leaf and the effects of the treatments grown to a great extent in 2011, while in 2012 the differences between treatments were moderate. Until the N150+PK level, nitrogen fertilisation had a notable effect on the maximum amount of SPAD values (59.1 in the case of the biculture and 54.0 in the triculture). The highest SPAD values were measured at the end of May (during the time of flowering and grain filling) in the biculture. In the triculture, showed high SPAD values from the beginning. The same tendency could be observed in the 2012 cropyear, although increasing doses of fertilizers resulted in higher SPAD values until N150+PK level only from the second measurement. Maximum SPAD values were reached at the end of May in both crop rotation system

Sign in / Sign up

Export Citation Format

Share Document