Peanut, a major economic and oil crop known for the high protein and oil content, is extensively cultivated in China. Peanut plants have the ability to form nodules with rhizobia, where the nitrogenase converts atmospheric nitrogen into ammonia nitrogen that can be utilized by the plants. Analysis of nodule fixation is of positive significance for avoiding overapplication of chemical fertilizer and developing sustainable agriculture. In this study, AhNIGT1.2, a member of the NIGT family predominantly expressed in peanut nodules, was identified by bioinformatics analysis. Subsequent spatiotemporal expression analysis revealed that AhNIGT1.2 was highly expressed in nodules and showed significant responses to high nitrogen, low nitrogen, high phosphorus, low phosphorus, and rhizobia treatments. Histochemical staining indicated that the gene was primarily expressed in developing nodules and at the connection region between mature nodules and peanut roots. The fusion protein AhNIGT1.2-GFP was located in the nucleus of tobacco epidermal cells. The AhNIGT1.2-OE significantly increased the number of peanut nodules, while AhNIGT1.2-RNAi reduced the number of nodules, which suggested a positive regulatory role of AhNIGT1.2 in peanut nodulation. The AhNIGT1.2-OE in roots down-regulated the expression levels of NRT1.2, NRT2.4, NLP1, and NLP7, which indicated that AhNIGT1.2 influenced peanut nodulation by modulating nitrate transport and the expression of NLP genes. The transcriptome analysis of AhNIGT1.2-OE and control roots revealed that overexpressing AhNIGT1.2 significantly enriched the differentially expressed genes associated with nitrate response, nodulation factor pathway, enzymes for triterpene biosynthesis, and carotenoid biosynthesis. These findings suggest that AhNIGT1.2 play a key role in peanut nodulation by regulating nitrate transport and response and other related pathways. This study gives insights into the molecular mechanisms of nitrogen and phosphorus in regulating legume nodulation and nitrogen fixation, and sheds light on the development of legume crops that can efficiently fix nitrogen in high nitrogen environments.
Arachis/physiology* ; Nitrates/metabolism* ; Plant Proteins/physiology* ; Transcription Factors/metabolism* ; Plant Root Nodulation/physiology* ; Gene Expression Regulation, Plant ; Root Nodules, Plant/metabolism* ; Nitrogen Fixation

Improving the nitrogen use efficiency (NUE) of Brassica napus is of significant importance for achieving the national goal of zero growth in chemical fertilizer application and ensuring the green development of the rapeseed industry. This study aims to explore the effects of the nitrate transporter gene BnaNRT1.5s on the nitrogen transport and NUE of B. napus, providing excellent genetic resources for the development of nitrogen-efficient B. napus varieties. The spatiotemporal expression of BnaA05.NRT1.5 as a key nitrogen responsive gene was profiled by qRT-PCR at different growth stages and for different tissue samples of B. napus 'Westar'. Subcellular localization was employed to examine its expression pattern in the cells. Additionally, CRISPR/Cas9 was used to create BnaNRT1.5s knockout lines, which were subjected to hydroponic experiments under high nitrogen (12.0 mmol/L) and low nitrogen (0.3 mmol/L) conditions. After the seedlings were cultivated for 21 days, root and shoot samples were collected for weighing, nitrogen content determination, xylem sap nitrate content assessment, and calculation of total nitrogen and NUE. The B. napus nitrate transporter BnaA05.NRT1.5 was localized to the cell membrane. During the seedling and early bolting stages, BnaA05.NRT1.5 was predominantly expressed in roots, while it was highly expressed in old leaves and mature silique skin during the reproductive stage. Compared with the wild type, the mutant BnaNRT1.5s showed significant increases in the dry weight and total nitrogen of seedlings under both high and low nitrogen conditions. Under low nitrogen conditions, NUE in the roots of BnaNRT1.5s significantly improved. Notably, under both high and low nitrogen conditions, the nitrate content in the shoots of BnaNRT1.5s decreased significantly, while that in the roots increased significantly, resulting in a significantly decreased shoot-to-root nitrate content ratio. BnaNRT1.5s is involved in regulating the transport of nitrate from the roots to the shoots, and its mutation enhances nitrogen absorption and utilization in B. napus seedlings, promoting seedling growth. This study not only provides references for understanding the physiological and molecular mechanisms by which BnaNRT1.5s regulates NUE but also offers valuable genetic resources for improving NUE in B. napus.
Brassica napus/genetics* ; Anion Transport Proteins/metabolism* ; Nitrogen/metabolism* ; Nitrate Transporters ; Plant Proteins/metabolism* ; Nitrates/metabolism* ; Gene Expression Regulation, Plant ; Biological Transport

Homeostasis is a dynamic balance process of self-regulating. Biological systems remain stable through adapting to changing external conditions to maintain normal life activities. Homeostatic medicine is the science of studying homeostasis of human molecules, cells, organs and the whole body. It is a comprehensive discipline based on maintaining homeostasis to keep human health and assist for diseases prevention and diagnoses. Homeostatic medicine focuses on the whole body and on the role of homeostasis in health and disease, which is expected to provide new ideas and strategies for maintaining health as well as diagnosing and treating diseases. Nitric oxide (NO) plays an important role in the control of multisystem homeostasis. Nitrate is an important substance in regulating NO homeostasis through the nitrate-nitrite-NO pathway. Sialin, nitrate transporter which is located in the cell membrane and cytoplasm, mediates multiple cellular biological functions. The nitrate-nitrite-NO pathway and sialin-mediated biological functions play an important role in the regulation of body homeostasis.
Humans ; Nitrates/metabolism* ; Nitrites/metabolism* ; Homeostasis ; Nitric Oxide

Nitrate is the main form of inorganic nitrogen that crop absorbs, and nitrate transporter 2 (NRT2) is a high affinity transporter using nitrate as a specific substrate. When the available nitrate is limited, the high affinity transport systems are activated and play an important role in the process of nitrate absorption and transport. Most NRT2 cannot transport nitrates alone and require the assistance of a helper protein belonging to nitrate assimilation related family (NAR2) to complete the absorption or transport of nitrates. Crop nitrogen utilization efficiency is affected by environmental conditions, and there are differences between varieties, so it is of great significance to develop varieties with high nitrogen utilization efficiency. Sorghum bicolor has high stress tolerance and is more efficient in soil nitrogen uptake and utilization. The S. bicolor genome database was scanned to systematically analyze the gene structure, chromosomal localization, physicochemical properties, secondary structure and transmembrane domain, signal peptide and subcellular localization, promoter region cis-acting elements, phylogenetic evolution, single nucleotide polymorphism (SNP) recognition and annotation, and selection pressure of the gene family members. Through bioinformatics analysis, 5 NRT2 gene members (designated as SbNRT2-1a, SbNRT2-1b, SbNRT2-2, SbNRT2-3, and SbNRT2-4) and 2 NAR2 gene members (designated as SbNRT3-1 and SbNRT3-2) were identified, the number of which was less than that of foxtail millet. SbNRT2/3 were distributed on 3 chromosomes, and could be divided into four subfamilies. The genetic structure of the same subfamilies was highly similar. The average value of SbNRT2/3 hydrophilicity was positive, indicating that they were all hydrophobic proteins, whereas α-helix and random coil accounted for more than 70% of the total secondary structure. Subcellular localization occurred on plasma membrane, where SbNRT2 proteins did not contain signal peptides, but SbNRT3 proteins contained signal peptides. Further analysis revealed that the number of transmembrane domains of the SbNRT2s family members was greater than 10, while that of the SbNRT3s were 2. There was a close collinearity between NRT2/3s of S. bicolor and Zea mays. Protein domains analysis showed the presence of MFS_1 and NAR2 protein domains, which supported executing high affinity nitrate transport. Phylogenetic tree analysis showed that SbNRT2/3 were more closely related to those of Z. mays and Setaria italic. Analysis of gene promoter cis-acting elements indicated that the promoter region of SbNRT2/3 had several plant hormones and stress response elements, which might respond to growth and environmental cues. Gene expression heat map showed that SbNRT2-3 and SbNRT3-1 were induced by nitrate in the root and stem, respectively, and SbNRT2-4 and SbNRT2-3 were induced by low nitrogen in the root and stem. Non-synonymous SNP variants were found in SbNRT2-4 and SbNRT2-1a. Selection pressure analysis showed that the SbNRT2/3 were subject to purification and selection during evolution. The expression of SbNRT2/3 gene and the effect of aphid infection were consistent with the expression analysis results of genes in different tissues, and SbNRT2-1b and SbNRT3-1 were significantly expressed in the roots of aphid lines 5-27sug, and the expression levels of SbNRT2-3, SbNRT2-4 and SbNRT3-2 were significantly reduced in sorghum aphid infested leaves. Overall, genome-wide identification, expression and DNA variation analysis of NRT2/3 gene family of Sorghum bicolor provided a basis for elucidating the high efficiency of sorghum in nitrogen utilization.
Nitrate Transporters ; Nitrates/metabolism* ; Sorghum/metabolism* ; Anion Transport Proteins/metabolism* ; Phylogeny ; Protein Sorting Signals/genetics* ; Nitrogen/metabolism* ; DNA ; Gene Expression Regulation, Plant ; Plant Proteins/metabolism*

NRT1 family proteins play an important roles for absorbing and transporting of nitrate in different plants. In order to identify the NRT1 family genes of Rehmannia glutinosa, this study used 11 NRT1 homologous proteins of Arabidopsis as probe sequences and aligned with the transcriptome data of R. glutinosa by using NCBI BLASTN software. Resulting there were 18 NRT1 proteins were identified in R. glutinosa. On basis of this, a series of the molecular characteristics of R. glutinosa NRT1 proteins including the conserved domains, the transmembrane structure, the subcellular location and phylogenetic features were in detail analyzed. At same time, it were systematically analyzed that the temporal and spatial expression patterns and characteristics of R. glutinosa NRT1 family genes in response to different stress factors. The results indicated that 18 R. glutinosa NRT1 family genes with the length of coding region from 1 260 bp to 1 806 bp, encoded proteins ranging from 419 to 601 amino acids, and all of they owned the domains of typical peptide transporter with 7 to 12 transmembrane domains. These R. glutinosa NRT1 family proteins mostly were found to locate on cellular plasma membrane, and belonged to the hydrophobic proteins. Furthermore, the evolutionary analysis found that the 18 R. glutinosa NRT1 protein family could be divided into two subfamilies, of which 14 NRT1 family genes might occur the positive selection, and 4 genes occur the passivation selection during the evolution process of R. glutinosa. In addition the expression analysis showed that 18 R. glutinosa NRT1 family genes have the distinct expression patterns in different tissues of R. glutinosa, and their expression levels were also obvious difference in response to various stress. These findings infield that 18 R. glutinosa NRT1 family proteins might have obviously different functional roles in nitrate transport of R. glutinosa. In conclusion, this study lays a solid theoretical foundation for clarifying the absorption and transport molecular mechanism of N element during R. glutinosa growth and development, and at same time for deeply studying the molecular function of R. glutinosa NRT1 proteins in absorption and transport of nitrate.
Anion Transport Proteins ; Membrane Transport Proteins ; Nitrates ; Phylogeny ; Plant Proteins/metabolism* ; Rehmannia/genetics* ; Transcriptome

The aim of this study was to establish a novel technology using microalgae for NO₃⁻ removal from high concentration wastewater and conversion to algal proteins. The effects of cultivation modes and illumination modes on the biomass yield, NO₃⁻ assimilation rate and algal protein yield were first investigated in shaking flasks for mixotrophic cultivation of Chlorella pyrenoidosa, and subsequently the scale-up verification in 5-L photo fermenter was successfully conducted. Fed-batch cultivation without medium recycling was the best cultivation mode in shaking flask system, in which the highest biomass yield (35.95 g/L), the average NO₃⁻ assimilation rate (2.06 g/(L·d)) and algal protein content (up to 42.44% of dry weight) were achieved. By using a staged increase of light intensity as illumination modes, the specific growth rate of cells could be significantly promoted to the highest (0.65 d⁻¹). After a 128-hour continuous cultivation in a 5-L photo fermenter, the highest biomass yield and the average NO₃⁻ assimilation rate were reached to 66.22 g/L and 4.38 g/(L·d) respectively, with the highest algal protein content at 47.13% of dry weight. Our study could provide a photo fermentation technology of microalgae for highly efficient treatment of waste industrial nitric acid and/or high concentration nitrate wastewater. This microalgae-based bioconversion process could coproduce protein-rich microalgal biomass, which facilitates the resource utilization of these type wastewater by trash-to-treasure conversion.
Algal Proteins ; biosynthesis ; Biomass ; Chlorella ; Nitrates ; isolation & purification ; metabolism ; Nitrogen ; metabolism ; Waste Water ; chemistry ; Water Purification ; methods

Vegetables are important constituents of the human diet. Heavy metals and nitrate are among the major contaminants of vegetables. Consumption of vegetables and fruits with accumulated heavy metals and nitrate has the potential to damage different body organs leading to unwanted effects. Breeding vegetables with low heavy metal and nitrate contaminants is a cost-effective approach. We investigated 38 water spinach genotypes for low Cd and nitrate co-accumulation. Four genotypes, i.e. JXDY, GZQL, XGDB, and B888, were found to have low co-accumulation of Cd (<0.71 mg/kg dry weight) and nitrate (<3100 mg/kg fresh weight) in the edible parts when grown in soils with moderate contamination of both Cd (1.10 mg/kg) and nitrate (235.2 mg/kg). These genotypes should be appropriate with minimized risk to humans who consume them. The Cd levels in the edible parts of water spinach were positively correlated with the concentration of Pb or Zn, but Cd, Pb, or Zn was negatively correlated with P concentration. These results indicate that these three heavy metals may be absorbed into the plant in similar proportions or in combination, minimizing the influx to aerial parts. Increasing P fertilizer application rates appears to prevent heavy metal and nitrate translocation to shoot tissues and the edible parts of water spinach on co-contaminated soils.
Biomass ; Cadmium/metabolism* ; Chlorophyll/analysis* ; Genotype ; Humans ; Ipomoea/genetics* ; Nitrates/metabolism*

To providing evidence about nitrogen adequate application of Platycodon grandiflorum, the pot culture experiment was conducted to study the effect of nitrogen on the growth, physiological metabolism and the quality of P. grandiflorum. The activity of NR, GS and SOD, POD and CAT were determined. And the nitrate and ammonium nitrogen content, photosynthetic characteristics, active components of P. grandiflorum were determined. The results showed that the nitrate nitrogen content and P. biomass reached its maximum value, when NH4(+)-N/NO3(-) -N was 0: 100, the activity of NR. The activity of GS was the highest at the NH4(+) -N/NO3(-) -N ratio of 25:75 and ammonium nitrogen content was the highest at 75:25. The activity of SOD decreased and then increased with the increasing of NO3(-) -N. At the NH4(+) -N/NO3(-) -N ratio of 25: 75, the activity of CAT had its maximum value and the content of MDA had the minimum value. At the same time, the content of platycodon D was the highest at this treatment. The studies had shown that different nitrogen forms and ratio had a significant effect on the characteristics of photosynthetic physiology, nitrogen metabolism and resistance adjustment, growth and the quality of P. grandiflorum. The NH4(+) -N/NO3(-) -N ratio of 25: 75 was a suitable ratio of nitrogen forms for the growth of P. Grandiflorum and accumulating the content of platycodon D.
Ammonium Compounds ; metabolism ; Biomass ; Drugs, Chinese Herbal ; analysis ; metabolism ; Nitrates ; metabolism ; Photosynthesis ; Plant Leaves ; chemistry ; growth & development ; metabolism ; Platycodon ; chemistry ; growth & development ; metabolism

Nitrate not only remarkably stimulates the rifamycinbiosynthesis in Amycolatopsis mediterranei, but also influences the primary metabolisms, including the inhibition of fatty acids biosynthesis in the bacterial. This phenomenon has been designated as "Nitrate Stimulating Effect" by the late Prof. J.S. Chiaosince its discovery in the 1970's, and has been found in many other antibiotics-producing actinomycetes subsequently. Based on the research in his laboratory, we have revealed that the nitrate stimulation effect mainly manifests in two aspects over the last two decades. First, nitrate promotes the supply of rifamycin precursors, e.g., UDP-glucose, AHBA, malonyl-CoA and methylmalonyl-CoA. Specifically, the biosynthesis of fatty acids is inhibited by nitrate consequently the acetyl-CoA is shunted into malonyl-CoA. Second, nitrate facilitates the expression of genes in the rifclulsterthat encodes rifamycin biosynthetic enzymes. Following our current understanding, the future research will focus on the signals, the signal transduction pathway and the molecular mechanisms that dictate nitrate-mediated transcriptional and post-translational regulations.
Actinomycetales ; classification ; metabolism ; Acyl Coenzyme A ; chemistry ; Anti-Bacterial Agents ; biosynthesis ; Nitrates ; chemistry ; Rifamycins ; biosynthesis

OBJECTIVEThe present study investigated the protective role of Hyparrhenia hirta (H. hirta) against sodium nitrate (NaNO3)-induced hepatoxicity.

METHODSMale Wistar rats were randomly divided into three groups: a control group and two treated groups during 50 d with NaNO3 administered either alone in drinking water or co-administered with H. hirta.

RESULTSNaNO3 treatment induced a significant increase in serum levels of glucose, total cholesterol and triglyceride while serum total protein level decreased significantly. Transaminases and lactate deshydrogenase activities in serum were elevated indicating hepatic cells' damage after treatment with NaNO3. The hyperbilirubinemia and the increased serum gamma glutamyl transferase activities suggested the presence of cholestasis in NaNO3 exposed rats. In parallel, a significant increase in malondialdehyde level along with a concomitant decrease in total glutathione content and superoxide dismutase, catalase and glutathione peroxidase activities were observed in the liver after NaNO3 treatment. Furthermore, nitrate caused a significant induction of DNA fragmentation. These modifications in NaNO3-treated rats corresponded histologically with hepatocellular necrosis and mononuclear cells infiltration. H. hirta supplementation showed a remarkable amelioration of the abnormalities cited above.

CONCLUSIONThe results concluded that the treatment with H. hirta had a significant role in protecting the animals from nitrate-induced liver dysfunction.

Animals ; Chemical and Drug Induced Liver Injury ; prevention & control ; DNA Fragmentation ; drug effects ; Drug Evaluation, Preclinical ; Eating ; drug effects ; Flavonoids ; analysis ; Glutathione ; drug effects ; Lipid Peroxidation ; drug effects ; Lipids ; blood ; Liver ; drug effects ; metabolism ; pathology ; Male ; Mice ; Nitrates ; Organ Size ; drug effects ; Phytotherapy ; Plant Extracts ; pharmacology ; therapeutic use ; Poaceae ; chemistry ; Random Allocation ; Rats, Wistar