Nitrogen Nutrition, Its Regulation and Biotechnological Approaches to Improve Crop Productivity

Reddy, Mettu Madhavi; Ulaganathan, Kandasamy

doi:10.4236/ajps.2015.618275

Cited by 19 publications

(17 citation statements)

References 448 publications

(473 reference statements)

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“…During translocation and assimilation, inorganic nitrogen influx and efflux also takes place between the roots and the recirculating water. The reason of NO 3 efflux on its biochemical basis has not been fully discovered (Reddy and Ulaganathan, 2015;Segonzac et al, 2007). However, it has been known that the NO 3 efflux is mediated by NO 3 transporters such as NO 3 transporter 1.5 (NRT1.5) and nitrate excretion transporter 1 (NAXT1) of root plasma membrane (Reddy and Ulaganathan, 2015;Segonzac et al, 2007).…”

Section: Nitrogen Uptake By Plantsmentioning

confidence: 99%

“…The reason of NO 3 efflux on its biochemical basis has not been fully discovered (Reddy and Ulaganathan, 2015;Segonzac et al, 2007). However, it has been known that the NO 3 efflux is mediated by NO 3 transporters such as NO 3 transporter 1.5 (NRT1.5) and nitrate excretion transporter 1 (NAXT1) of root plasma membrane (Reddy and Ulaganathan, 2015;Segonzac et al, 2007). The NO 3 efflux is induced by stressed conditions such as medium acidification, defoliation, mechanical stress, transplant shock and pathogen attacks (Reddy and Ulaganathan, 2015;Segonzac et al, 2007).…”

Section: Nitrogen Uptake By Plantsmentioning

confidence: 99%

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Nitrogen transformations in aquaponic systems: A review

Wongkiew

Chandran

et al. 2017

Aquacultural Engineering

245

139

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In recent years, aquaponic systems have gained significant popularity as soilless agriculture systems for organic fruits and vegetables production with concomitant remediation of aquaculture effluent. Aquaponics is a potential sustainable food production system that integrates aquaculture with hydroponics in which nitrogen-rich effluent from the fish production is utilized for plant growth. Because nitrogen is one of the most important inputs in an aquaponic system, it is critical to investigate the nitrogen transformations in the system for enhanced recovery of resources. Since studies on nitrogen transformations and nitrogen utilization efficiency (NUE) in aquaponic systems have been very limited, this review critically examines the important fates of nitrogen from input to outputs (e.g., ammonia nitrogen generation, nitrification, nitrate assimilation and nitrogen loss) to improve NUE in aquaponic systems. Various factors affecting the nitrogen transformations are also discussed. Furthermore, an example of nitrogen imbalance between nitrate uptake and nitrate generation rates in an aquaponic system was demonstrated. This review aims to advance our current understanding of nitrogen transformations and outlines future research needs in aquaponic systems, a sustainable model for efficient water and nutrient managements, and food production.

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Section: Nitrogen Uptake By Plantsmentioning

confidence: 99%

Section: Nitrogen Uptake By Plantsmentioning

confidence: 99%

Nitrogen transformations in aquaponic systems: A review

Wongkiew

Chandran

et al. 2017

Aquacultural Engineering

245

139

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“…Glutamine synthetase also mediates ammonium assimilation into glutamine. Ammonium form of nitrogen is rapidly assimilated into organic nitrogen forms to avoid tissue toxicity, for review see [196]. Several other reviews have documented the genes and proteins regulating nitrogen use efficiency (NUE) in plants.…”

Section: Plant Tolerance To Nitrogen Deficiencymentioning

confidence: 99%

“…Several other reviews have documented the genes and proteins regulating nitrogen use efficiency (NUE) in plants. The reader is referred to excellent reviews by [177,196]. In addition, more than 50 QTLs for nitrogen use efficiency have been reported in plants, though few of them have been validated.…”

Section: Plant Tolerance To Nitrogen Deficiencymentioning

confidence: 99%

Advances in Plant Tolerance to Abiotic Stresses

Onaga¹,

Wydra²

2016

Plant Genomics

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During the last 50 years, it has been shown that abiotic stresses influence plant growth and crop production greatly, and crop yields have evidently stagnated or decreased in economically important crops, where only high inputs assure high yields. The recent manifesting effects of climate change are considered to have aggravated the negative effects of abiotic stresses on plant productivity. On the other hand, the complexity of plant mechanisms controlling important traits and the limited availability of germplasm for tolerance to certain stresses have restricted genetic advances in major crops for increased yields or for improved other traits. However, some level of success has been achieved in understanding crop tolerance to abiotic stresses; for instance, identification of abscisic acid (ABA) receptors (e.g., ABA-responsive element (ABRE) binding protein/ABRE binding factor (AREB/ABF) transcription factors), and other regulons (e.g., WRKYs, MYB/ MYCs, NACs, HSFs, bZIPs and nuclear factor-Y (NF-Y)), has shown potential promise to improve plant tolerance to abiotic stresses. Apart from these major regulons, studies on the post-transcriptional regulation of stress-responsive genes have provided additional opportunities for addressing the molecular basis of cellular stress responses in plants. This chapter focuses on the progress in the study of plant tolerance to abiotic stresses, and describes the major tolerance pathways and implicated signaling factors that have been identified, so far. To link basic and applied research, genes and proteins that play functional roles in mitigating abiotic stress damage are summarized and discussed.In the past 100 years, conventional breeding ( Figure 2; based on observed variation and controlled mating) approaches have randomly exploited these plant tolerance mechanisms with limited success. Moreover, in vitro induced variations have also shown little progress in the improvement of plants against abiotic stresses. These conventional breeding approaches are limited by the complexity of stress tolerance traits coupled with less genetic Plant Genomics 168 variation exhibited by most crops due to domestication bottlenecks. The recent reports that the cultivated gene pool of major cereal crops, e.g., rice, maize and wheat, has reduced in genetic variation compared to wild relatives [10-12], raises concern, and could probably undermine the current efforts to identify genetic sources of resistance within the cultivated genepools. It is important, therefore, to consider exploring alternative sources of resistance by incorporating modern techniques into traditional breeding strategies to develop stresstolerant crops (Figure 2).Recently, with the support of genomics, targeted genetic studies involving QTL mapping and validation, identification of key regulatory genes, e.g., genes encoding for ABA receptors, developments in transcriptional and post-transcriptional regulation of stress-responsive genes and studies on hormonal interactions during plant response to stress, have provided opp...

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“…Moreover, studies have shown that plants have developed an advanced mechanism to deal with nitrogen deficiency, through uptake, transport, and assimilation of nitrogen under N-limited environment [11]. Furthermore, the plants only utilize 30% of the applied nitrogenous fertilizers, while the rest is either lost through leaching and or fixed in the soil [12].…”

Section: Introductionmentioning

confidence: 99%

Map-Based Functional Analysis of the GhNLP Genes Reveals Their Roles in Enhancing Tolerance to N-Deficiency in Cotton

Magwanga

Kirungu

et al. 2019

IJMS

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Nitrogen is a key macronutrient needed by plants to boost their production, but the development of cotton genotypes through conventional approaches has hit a bottleneck due to the narrow genetic base of the elite cotton cultivars, due to intensive selection and inbreeding. Based on our previous research, in which the BC2F2 generations developed from two upland cotton genotypes, an abiotic stress-tolerant genotype, G. tomentosum (donor parent) and a highly-susceptible, and a highly-susceptible, but very productive, G. hirsutum (recurrent parent), were profiled under drought stress conditions. The phenotypic and the genotypic data generated through genotyping by sequencing (GBS) were integrated to map drought-tolerant quantitative trait loci (QTLs). Within the stable QTLs region for the various drought tolerance traits, a nodule-inception-like protein (NLP) gene was identified. We performed a phylogenetic analysis of the NLP proteins, mapped their chromosomal positions, intron-exon structures and conducted ds/dn analysis, which showed that most NLP genes underwent negative or purifying selection. Moreover, the functions of one of the highly upregulated genes, Gh_A05G3286 (Gh NLP5), were evaluated using the virus gene silencing (VIGS) mechanism. A total of 226 proteins encoded by the NLP genes were identified, with 105, 61, and 60 in Gossypium hirsutum, G. raimondii, and G. arboreum, respectively. Comprehensive Insilico analysis revealed that the proteins encoded by the NLP genes had varying molecular weights, protein lengths, isoelectric points (pI), and grand hydropathy values (GRAVY). The GRAVY values ranged from a negative one to zero, showing that proteins were hydrophilic. Moreover, various cis-regulatory elements that are the binding sites for stress-associated transcription factors were found in the promoters of various NLP genes. In addition, many miRNAs were predicted to target NLP genes, notably miR167a, miR167b, miR160, and miR167 that were previously shown to target five NAC genes, including NAC1 and CUC1, under N-limited conditions. The real-time quantitative polymerase chain reaction (RT-qPCR) analysis, revealed that five genes, Gh_D02G2018, Gh_A12G0439, Gh_A03G0493, Gh_A03G1178, and Gh_A05G3286 were significantly upregulated and perhaps could be the key NLP genes regulating plant response under N-limited conditions. Furthermore, the knockdown of the Gh_A05G3286 (GhNLP5) gene by virus-induced silencing (VIGS) significantly reduced the ability of these plants to the knockdown of the Gh_A05G3286 (GhNLP5) gene by virus-induced gene silencing (VIGS) significantly reduced the ability of the VIGS-plants to tolerate N-limited conditions compared to the wild types (WT). The VIGS-plants registered lower chlorophyll content, fresh shoot biomass, and fresh root biomass, addition to higher levels of malondialdehyde (MDA) and significantly reduced levels of proline, and superoxide dismutase (SOD) compared to the WT under N-limited conditions. Subsequently, the expression levels of the Nitrogen-stress responsive gen...

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Nitrogen Nutrition, Its Regulation and Biotechnological Approaches to Improve Crop Productivity

Cited by 19 publications

References 448 publications

Nitrogen transformations in aquaponic systems: A review

Nitrogen transformations in aquaponic systems: A review

Advances in Plant Tolerance to Abiotic Stresses

Map-Based Functional Analysis of the GhNLP Genes Reveals Their Roles in Enhancing Tolerance to N-Deficiency in Cotton

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