Nitrogen Journey in Plants: From Uptake to Metabolism, Stress Response, and Microbe Interaction

Abstract

Plants uptake and assimilate nitrogen from the soil in the form of nitrate, ammonium ions, and available amino acids from organic sources. Plant nitrate and ammonium transporters are responsible for nitrate and ammonium translocation from the soil into the roots. The unique structure of these transporters determines the specificity of each transporter, and structural analyses reveal the mechanisms by which these transporters function. Following absorption, the nitrogen metabolism pathway incorporates the nitrogen into organic compounds via glutamine synthetase and glutamate synthase that convert ammonium ions into glutamine and glutamate. Different isoforms of glutamine synthetase and glutamate synthase exist, enabling plants to fine-tune nitrogen metabolism based on environmental cues. Under stressful conditions, nitric oxide has been found to enhance plant survival under drought stress. Furthermore, the interaction between salinity stress and nitrogen availability in plants has been studied, with nitric oxide identified as a potential mediator of responses to salt stress. Conversely, excessive use of nitrate fertilizers can lead to health and environmental issues. Therefore, alternative strategies, such as establishing nitrogen fixation in plants through diazotrophic microbiota, have been explored to reduce reliance on synthetic fertilizers. Ultimately, genomics can identify new genes related to nitrogen fixation, which could be harnessed to improve plant productivity.

Microbiological Biostimulants in the Improvement of Extended Storage Quality of In Vitro-Derived Plants of Popular Ornamental Perennials

“…The specific bacterial strains in BactoFungiStop, AzotoPower, and Guard may have different affinities for certain plant species, influencing the effectiveness of the treatments. The strains of Azotobacter and Arthrobacter genera in AzotoPower, for example, are involved in supporting nitrogen fixation, which may have different effects on plants with varying nitrogen requirements [29]. This could explain the positive responses found in Brunnera macrophylla, Echinacea purpurea, and Heuchera × hybrida, which may have benefited from increased nitrogen availability.…”

Soil sample storage conditions affect measurements of pH, potassium, and nitrogen

“…Freezing resulted in a continuous increase of NO 2 -N such that the levels at Week 24 were 0.66 mg/kg higher compared to the fresh control. While these changes were significant, the total NO 2 -N was very low and since NO 2 -N is not as readily acquired by plants as NO 3 -N and NH 4 -N (Zayed et al, 2023), it is unlikely that a change of <1 mg/kg reflects an agriculturally important difference. Nonetheless, for studies where accurate measurements of soil NO 2 -N are required, we suggest refrigeration as the optimal soil sample storage method.…”

The wild emmer wheat grain protein content 5B QTL introgressed into bread wheat is associated with tolerance to nitrogen deficiency .

“…NUE is relatively low in cultivated wheat, it is a multifaceted trait in uenced by numerous genes with complex environmental interplay. It includes genes associated with N uptake, assimilation, and partitioning, which vary among wheat cultivars, with some exhibiting better NUtE, leading to higher GPC (Tegeder 2014 Zayed et al 2023). Some of these genes have been found to improve the reaction the effect of N de ciency in wheat by causing the accumulation of abscisic acid (ABA), especially in guard cells, which leads to stomatal closure (Wilkinson et al 2007;Seo and Koshiba 2011).…”