scholarly journals Systemic regulation of nitrogen acquisition and use in Oryza longistaminata ramets under nitrogen heterogeneity

2021 ◽  
Author(s):  
Misato Kawai ◽  
Ryo Tabata ◽  
Miwa Ohashi ◽  
Haruno Honda ◽  
Tekehiro Kamiya ◽  
...  
Keyword(s):  
Nitrogen Availability ◽  
Ammonium Assimilation ◽  
Ammonium Uptake ◽  
Growth Strategies ◽  
Hydroponic System ◽  
Nitrogen Acquisition ◽  
Oryza Longistaminata ◽  
Gene Regulatory ◽  
Water Nutrients ◽  
Compensatory Regulation

Oryza longistaminata, a wild rice, vegetatively reproduces and forms a networked clonal colony consisting of ramets connected by rhizomes. Although water, nutrients, and other molecules can be transferred between ramets via the rhizomes, inter-ramet communication in response to spatially heterogeneous nitrogen availability is not well understood. We studied the response of ramet pairs to heterogeneous nitrogen availability by using a split hydroponic system that allowed each ramet root to be exposed to different conditions. Ammonium uptake was compensatively enhanced in the sufficient-side root when roots of the ramet pairs were exposed to ammonium-sufficient and deficient conditions. Comparative transcriptome analysis revealed that a gene regulatory network for effective ammonium assimilation and amino acid biosynthesis was activated in the sufficient-side roots. Allocation of absorbed nitrogen from the nitrogen-sufficient to the deficient ramets was rather limited. Nitrogen was preferentially used for newly growing axillary buds on the sufficient-side ramets. Biosynthesis of trans-zeatin, a cytokinin, was up-regulated in response to the nitrogen supply, but trans-zeatin appears not to target the compensatory regulation. Our results also implied that the O. longistaminata ortholog of OsCEP1 plays a role as a nitrogen-deficient signal in inter-ramet communication, providing compensatory up-regulation of nitrogen assimilatory genes. These results provide insights into the molecular basis for efficient growth strategies of asexually proliferating plants growing in areas where nitrogen distribution is spatially heterogeneous.

Over-expression of the rice OsAMT1-1 gene increases ammonium uptake and content, but impairs growth and development of plants under high ammonium nutrition

2006 ◽  
Vol 33 (2) ◽  
pp. 153 ◽  
Author(s):  
Mohammad S. Hoque ◽  
Josette Masle ◽  
Michael K. Udvardi ◽  
Peter R. Ryan ◽  
Narayana M. Upadhyaya
Keyword(s):  
Transgenic Plants ◽  
Ammonium Assimilation ◽  
Ammonium Transporter ◽  
Ammonium Uptake ◽  
Vegetative Stage ◽  
Over Expression ◽  
Transgenic Lines ◽  
Ammonium Nutrition ◽  
Maize Ubiquitin Promoter

A transgenic approach was undertaken to investigate the role of a rice ammonium transporter (OsAMT1-1) in ammonium uptake and consequent ammonium assimilation under different nitrogen regimes. Transgenic lines overexpressing OsAMT1-1 were produced by Agrobacterium-mediated transformation of two rice cultivars, Taipei 309 and Jarrah, with an OsAMT1-1 cDNA gene construct driven by the maize ubiquitin promoter. Transcript levels of OsAMT1-1 in both Taipei 309 and Jarrah transgenic lines correlated positively with transgene copy number. Shoot and root biomass of some transgenic lines decreased during seedling and early vegetative stage compared to the wild type, especially when grown under high (2 mm) ammonium nutrition. Transgenic plants, particularly those of cv. Jarrah recovered in the mid-vegetative stage under high ammonium nutrition. Roots of the transgenic plants showed increased ammonium uptake and ammonium content. We conclude that the decreased biomass of the transgenic lines at early stages of growth might be caused by the accumulation of ammonium in the roots owing to the inability of ammonium assimilation to match the greater ammonium uptake.

scholarly journals Functional Genomic Analysis of Three Nitrogenase Isozymes in the Photosynthetic Bacterium Rhodopseudomonas palustris

2005 ◽  
Vol 187 (22) ◽  
pp. 7784-7794 ◽  
Author(s):  
Yasuhiro Oda ◽  
Sudip K. Samanta ◽  
Federico E. Rey ◽  
Liyou Wu ◽  
Xiudan Liu ◽  
...  
Keyword(s):  
Nitrogen Availability ◽  
Rhodopseudomonas Palustris ◽  
Genomic Analysis ◽  
Photosynthetic Bacterium ◽  
Growth Media ◽  
Nitrogen Fixing ◽  
Nitrogen Acquisition ◽  
Functional Genomic Analysis ◽  
Alternative Nitrogenase ◽  
Dependent Growth

ABSTRACT The photosynthetic bacterium Rhodopseudomonas palustris is one of just a few prokaryotes described so far that has vnf and anf genes for alternative vanadium cofactor (V) and iron cofactor (Fe) nitrogenases in addition to nif genes for a molybdenum cofactor (Mo) nitrogenase. Transcriptome data indicated that the 32 genes in the nif gene cluster, but not the anf or vnf genes, were induced in wild-type and Mo nitrogenase-expressing strains grown under nitrogen-fixing conditions in Mo-containing medium. Strains that were unable to express a functional Mo nitrogenase due to mutations in Mo nitrogenase structural genes synthesized functional V and Fe nitrogenases and expressed vnf and anf genes in nitrogen-fixing growth media that contained Mo and V at concentrations far in excess of those that repress alternative nitrogenase gene expression in other bacteria. Thus, not only does R. palustris have multiple enzymatic options for nitrogen fixation, but in contrast to reports on other nitrogen-fixing bacteria, the expression of its alternative nitrogenases is not repressed by transition metals. Between 95 and 295 genes that are not directly associated with nitrogenase synthesis and assembly were induced under nitrogen-fixing conditions, depending on which nitrogenase was being used by R. palustris. Genes for nitrogen acquisition were expressed at particularly high levels during alternative nitrogenase-dependent growth. This suggests that alternative nitrogenase-expressing cells are relatively starved for nitrogen and raises the possibility that fixed nitrogen availability may be the primary signal that controls the synthesis of the V and Fe nitrogenases.

scholarly journals Switchgrass Rhizosphere Metabolite Chemistry Driven by Nitrogen Availability

2019 ◽  
Author(s):  
Darian N. Smercina ◽  
Alan W. Bowsher ◽  
Sarah E. Evans ◽  
Maren L. Friesen ◽  
Elizabeth K. Eder ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Panicum Virgatum ◽  
Root Exudate ◽  
Soil Microorganisms ◽  
Nitrogen Availability ◽  
N Availability ◽  
Free Living ◽  
Hydroponic System ◽  
Chemical Fingerprints ◽  
Inoculation Treatment

AbstractPlants and soil microorganisms interact closely in the rhizosphere where plants may exchange carbon (C) for functional benefits from the microbial community. For example, the bioenergy crop, switchgrass (Panicum virgatum) is thought to exchange root-exuded C for nitrogen (N) fixed by diazotrophs (free-living N-fixers). However, this interaction is not well characterized and it is not known how or if switchgrass responds to diazotrophs or their activity. To explore this question, we assessed rhizosphere metabolite chemistry of switchgrass grown in a hydroponic system under two N levels and under inoculated or uninoculated conditions. We found switchgrass root exudate chemistry to be more responsive to N availability than to diazotroph presence. Total metabolite concentrations were generally greater under high N versus low N and unaffected by inoculation. Examination of rhizosphere chemical fingerprints indicates metabolite chemistry was also driven strongly by N availability with a greater relative abundance of carbohydrates under high N and greater relative abundance of organic acids under low N. We also found evidence of changes in rhizosphere chemical fingerprints by inoculation treatment suggesting a potential for switchgrass to respond or even recruit diazotrophs. However, we found little evidence of N treatment and inoculation interaction effects which suggests switchgrass response to diazotroph presence is not mediated by N availability.

scholarly journals EFFECT OF CONCENTRATION AND N:K RATIO IN NUTRIENT SOLUTION FOR HYDROPONIC PRODUCTION OF CUCUMBER

2017 ◽  
Vol 30 (4) ◽  
pp. 818-824 ◽  
Author(s):  
DEISE SILVA CASTRO PIMENTEL CARDOSO ◽  
MARIA APARECIDA NOGUEIRA SEDIYAMA ◽  
YONARA POLTRONIERI ◽  
MAIRA CHRISTINA MARQUES FONSECA ◽  
YANE FERNANDES NEVES
Keyword(s):  
Nutrient Solution ◽  
Nitrogen Availability ◽  
Block Design ◽  
Dry Mass ◽  
Hydroponic System ◽  
Aerial Parts ◽  
Lack Of Information ◽  
Randomized Block Design ◽  
Hydroponic Cultivation ◽  
Nutrient Solutions

ABSTRACT The N:K ratio influences the balance between vegetative and reproductive stages, because potassium plays important roles in the processes that regulate plant growth when the nitrogen availability is high. However, there is a lack of information on the N:K ratio suitable for cucumber cultivation in an NFT-hydroponic system. The objective of this study is to evaluate the different N:K ratios in fruiting nutrient solutions for cucumber production in a hydroponic system. Treatments consisted of two cucumber hybrids (Natsuno Kagayaki and Runner) and four nutrition solutions with different N:K ratios (w/w) (1:0.5, 1:1.0, 1:2.0, and 1:3.0) in the reproductive phase arranged as split plots in a randomized block design with four replications. On the 33rd day after sowing (DAS), the SPAD index on the fourth expanded leaf from the plant apex, number of broaches, and harvests were evaluated. The aerial parts of the plants were collected on the 54th DAS for evaluation of fresh mass, dry mass, and number of leaves per plant. The results showed that the highest concentration of K in the fruiting nutrient solution does not alter the length of the fruits but increases their diameter yield. The N:K ratios in the 1:2.0 and 1:3.0 (w/w) nutrient solutions provided greater yields in both evaluated hybrids. The hybrid Natsuno Kagayaki, however, showed the highest productivity, and it is recommended for hydroponic cultivation.

scholarly journals Heterotrophic Foraminifera Capable of Inorganic Nitrogen Assimilation

2020 ◽  
Vol 11 ◽  
Author(s):  
Clare Bird ◽  
Charlotte LeKieffre ◽  
Thierry Jauffrais ◽  
Anders Meibom ◽  
Emmanuelle Geslin ◽  
...  
Keyword(s):  
Nitrogen Availability ◽  
Secondary Ion Mass Spectrometry ◽  
Inorganic Nitrogen ◽  
Glutamate Synthase ◽  
Ammonium Assimilation ◽  
Biological Productivity ◽  
Benthic Species ◽  
Transmission Electron ◽  
Secondary Ion ◽  
Innate Ability

Nitrogen availability often limits biological productivity in marine systems, where inorganic nitrogen, such as ammonium is assimilated into the food web by bacteria and photoautotrophic eukaryotes. Recently, ammonium assimilation was observed in kleptoplast-containing protists of the phylum foraminifera, possibly via the glutamine synthetase/glutamate synthase (GS/GOGAT) assimilation pathway imported with the kleptoplasts. However, it is not known if the ubiquitous and diverse heterotrophic protists have an innate ability for ammonium assimilation. Using stable isotope incubations (15N-ammonium and 13C-bicarbonate) and combining transmission electron microscopy (TEM) with quantitative nanoscale secondary ion mass spectrometry (NanoSIMS) imaging, we investigated the uptake and assimilation of dissolved inorganic ammonium by two heterotrophic foraminifera; a non-kleptoplastic benthic species, Ammonia sp., and a planktonic species, Globigerina bulloides. These species are heterotrophic and not capable of photosynthesis. Accordingly, they did not assimilate 13C-bicarbonate. However, both species assimilated dissolved 15N-ammonium and incorporated it into organelles of direct importance for ontogenetic growth and development of the cell. These observations demonstrate that at least some heterotrophic protists have an innate cellular mechanism for inorganic ammonium assimilation, highlighting a newly discovered pathway for dissolved inorganic nitrogen (DIN) assimilation within the marine microbial loop.

The effect of ammonium on photosynthesis and the pathway of ammonium assimilation in Gymnodinium microadriaticum in vitro and in symbiosis with tridacnid clams and corals

1986 ◽  
Vol 227 (1247) ◽  
pp. 147-159 ◽  
Keyword(s):  
Amino Acids ◽  
Ammonium Assimilation ◽  
Water Soluble ◽  
Ammonium Uptake ◽  
Ammonium Ion ◽  
Ammonium Ions ◽  
Tissue Slices ◽  
Marine Animals ◽  
Symbiotic Algae

The effects of added ammonium ion (10-1000 μM) on photosynthetic 14 CO 2 fixation by tissues slices from the mantle of tridacnid clams, by coral tips, and by isolated zooxanthellae from clam mantle were examined. Ammonium ions stimulated photosynthesis in tissue slices but not in freshly isolated zooxanthellae. When ammonium stimulated 14 CO 2 fixation by coral tips an increase in water-soluble labelled compounds, especially amino acids, was observed. Even though ammonium ions did not stimulate photosynthesis in isolated zooxanthellae from clam mantle, light stimulated ammonium uptake in these cells. Studies with 15 NH + 4 confirmed earlier observations (in zooxanthellae isolated from Hippopus ) of light-stimulated transfer of ammonium from the amido-N of glutamine to the amino-N of glutamate, glutamine and other amino acids. This observation, in isolated zooxanthellae and tissue slices, suggests that the glutamine synthase-glutamate synthetase pathway of ammonium incorporation is light-driven in these systems. The possible significance of these processes during ammonium recycling by symbiotic algae in marine animals is discussed.

scholarly journals Ammonium Uptake Is the Main Driver of Rhizosphere pH in Southern Highbush Blueberry

HortScience ◽  
2019 ◽  
Vol 54 (5) ◽  
pp. 955-959 ◽  
Author(s):  
Christopher S. Imler ◽  
Camila I. Arzola ◽  
Gerardo H. Nunez
Keyword(s):  
N Uptake ◽  
Vaccinium Corymbosum ◽  
Ammonium Uptake ◽  
Highbush Blueberry ◽  
Rhizosphere Ph ◽  
Hydroponic System ◽  
Rhizosphere Acidification ◽  
Horticultural Crops ◽  
Main Driver ◽  
Southern Highbush

Unlike most horticultural crops, blueberry (Vaccinium spp. section cyanococcus) prefers low-pH (4.2–5.5) soils. Other plants can acidify their rhizosphere to create a hospitable microenvironment. Southern highbush blueberry (SHB; Vaccinium corymbosum interspecific hybrids) plants do not acidify their rhizosphere in response to Fe deficiency, but other factors that affect rhizosphere pH have not been elucidated. We report results from two hydroponic experiments exploring N uptake effects on the rhizosphere pH of ‘Emerald’ SHB. Ammonium (NH4+) uptake led to rhizosphere acidification, whereas nitrate (NO3–) uptake led to rhizosphere alkalization. When grown in a split-root hydroponic system, roots that took up NH4+ acidified the rhizosphere to a greater extent that roots not exposed to NH4+. Rhizosphere acidification was observed even in a nontreated control. These results suggest that NH4+ uptake is the main driver of rhizosphere pH in SHB. N form effects suggest that fertilization with NO3– might lead to undesirable rhizosphere alkalization.

scholarly journals Uptake and assimilation of ammonium ions by cucumber seedlings from solutions with different pH and addition of heavy metals

2014 ◽  
Vol 67 (2) ◽  
pp. 197-200 ◽  
Author(s):  
Marek Burzyński ◽  
Józef Buczek
Keyword(s):  
Heavy Metals ◽  
Ammonium Assimilation ◽  
Ammonium Uptake ◽  
Ferric Ions ◽  
Ammonium Ions ◽  
Root Cells ◽  
Cucumber Seedlings ◽  
Ph Conditions ◽  
High Level ◽  
Influence Of Ph

Influence of Cu<sup>2+</sup>, Cd<sup>2+</sup>, Pb<sup>2+</sup> and Fe<sup>2+</sup> in various pH conditions (5.0, 6.0, 7.0) on the uptake and assimilation of NH<sub>4</sub><sup>+</sup> by cucumber seedlings was estimated. Every metal in different pH of uptake solution distinctly reduced ammonium absorption calculated from NH<sub>4</sub><sup>+</sup> depletion. Copper and ferric ions, but not cadmium or lead, astonishingly decreased the uptake of ammonium from solution at pH 5.0. Cu<sup>2+</sup> was also very active at pH 6.0. The accumulation of ammonium in roots of metals-treated seedlings at the same time was high. The high level of ammonium in root cells despite of its low uptake probably resulted from disturbance in NH<sub>4</sub><sup>+</sup> assimilation. Both glutamine synthetase (GS) and NADH-glutamate dehydrogenase (NADH-GDH) - the major enzymes in ammonium assimilation, were inhibited after one hour of plant exposition to the metals. Similarly as in the case of ammonium uptake, the influence of pH was visible only in combination with copper and ferric ions. The strongest reduction of enzyme activities was observed for Cu<sup>2+</sup> and Fe<sup>2+</sup>, in pH 5.0 and 6.0. The various metals absorption by roots from solutions with different pH was not dedected. The data show correlation between metal inhibition of GS and NADH-GDH activities and metal inhibition of ammonium absorption.

TheAzospirillum brasilense rpoNgene is involved in nitrogen fixation, nitrate assimilation, ammonium uptake, and flagellar biosynthesis

1996 ◽  
Vol 42 (5) ◽  
pp. 467-478 ◽  
Author(s):  
Anne Milcamps ◽  
Anne Van Dommelen ◽  
John Stigter ◽  
Jos Vanderleyden ◽  
Frans J. de Bruijn
Keyword(s):  
Nitrogen Fixation ◽  
Azospirillum Brasilense ◽  
Nitrate Assimilation ◽  
Ammonium Assimilation ◽  
Gene Replacement ◽  
Ammonium Uptake ◽  
Significant Similarity ◽  
Sigma 54 ◽  
Azospirillum Brasilense Sp7

The rpoN (ntrA) gene (encoding sigma 54) of Azospirillum brasilense Sp7 was isolated by using conserved rpoN primers and the polymerase chain reaction, and its nucleotide sequence was determined. The deduced amino acid sequence of the RpoN protein was found to share a high degree of homology with other members of the sigma 54 family. Two additional open reading frames were found in the Azospirillum brasilense rpoN region, with significant similarity to equivalent regions surrounding the rpoN locus in other bacteria. An rpoN mutant of Azospirillum brasilense Sp7 was constructed by gene replacement and found to be defective in nitrogen fixation, nitrate assimilation, and ammonium uptake. Lack of ammonium uptake was also found in previously isolated Azospirillum brasilense ntrB and ntrC mutants, further supporting the role of the ntr system in this process. In addition, the rpoN mutant was found to be nonmotile, suggesting a role of RpoN in Azospirillum brasilense flagellar biosynthesis.Key words: Azospirillum brasilense, sigma factor, nitrogen fixation, ammonium assimilation, motility.

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