Role of Nitrate Reductase in NO Production in Photosynthetic Eukaryotes

Tejada‐Jiménez, Manuel; Llamas, Ángel; Galván, Aurora; Fernández, Emilio

doi:10.3390/plants8030056

Cited by 67 publications

(36 citation statements)

References 110 publications

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“…() have shown that NO accumulation was present in the root‐knot nematode Meloidogyne incognita infected‐tomato roots at early stages of infection. However, the NO issue remains unexplained during plant infection with cyst nematodes, and this is important because NO synthesis in plants is coordinated with N metabolism (Tejada‐Jimenez et al , ). Our research team are therefore working on this issue, and our experiments have shown that the role of NO metabolism during plant–CN interactions is significant (authors' unpublished data).…”

Section: Discussionmentioning

confidence: 99%

Heterodera schachtii infection affects nitrogen metabolism in Arabidopsis thaliana

et al. 2020

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Nitrogen metabolism is important for physiological processes during normal growth and development, as well as plant defence responses. Second‐stage juveniles of the cyst nematode Heterodera schachtii penetrate into the root and initiate permanent feeding sites called syncytia, from which they draw all necessary nutrients. To unravel whether the cyst nematode infestation changes nitrogen metabolism, the enzymatic activity and gene expression of nitrate (NIA) and nitrite (NIR) reductases and glutamate dehydrogenase (GDH), as well as levels of the metabolites nitrates, nitrites, and ammonium ions were estimated both locally in inoculated roots and systemically in shoots of inoculated Arabidopsis thaliana plants at 3, 7, and 15 days post‐inoculation (dpi). Moreover, gene expression of long hypocotyle 5 (HY5), a basic‐region leucine zipper (bZIP) transcription factor, was also determined, to learn more about the potential transcriptional regulation of the analysed enzymes. It was shown that the activity of nitrogen‐related enzymes and the content of metabolites fluctuated during the whole period of infection. These results were accompanied by organ‐specific and dpi‐dependent gene expression patterns. The high gene expression level of HY5 in infected roots at 7 and 15 dpi coexisted with enhanced expression of NIA1 and NIR1 at 7 dpi and NIA2 at 15 dpi. Enhanced HY5 expression level in shoots of infected plants at 15 dpi was followed by up‐regulation of NIA1 expression, suggesting that HY5 may regulate the gene expression of NIA and NIR during nematode infection. Our results indicate that changes in plant nitrogen metabolism occur during cyst nematode infection.

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Section: Discussionmentioning

confidence: 99%

Heterodera schachtii infection affects nitrogen metabolism in Arabidopsis thaliana

et al. 2020

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“…In order to determine whether N 2 O production can be evidenced in the absence of exogenous NO supply, algae were supplied with nitrite as a nitrogen source, nitrite reduction being documented as an important source of intracellular NO (28). Note that we did not use nitrate here since the C. reinhardtii mutant strains used in this study all lack the nitrate reductase (27).…”

Section: Light-dependent N 2 O Photoproduction Mostly Relies On Flvsmentioning

confidence: 99%

Algal photosynthesis converts nitric oxide into nitrous oxide

Burlacot

Richaud

Gosset

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Nitrous oxide (N2O), a potent greenhouse gas in the atmosphere, is produced mostly from aquatic ecosystems, to which algae substantially contribute. However, mechanisms of N2O production by photosynthetic organisms are poorly described. Here we show that the green microalga Chlamydomonas reinhardtii reduces NO into N2O using the photosynthetic electron transport. Through the study of C. reinhardtii mutants deficient in flavodiiron proteins (FLVs) or in a cytochrome p450 (CYP55), we show that FLVs contribute to NO reduction in the light, while CYP55 operates in the dark. Both pathways are active when NO is produced in vivo during the reduction of nitrites and participate in NO homeostasis. Furthermore, NO reduction by both pathways is restricted to chlorophytes, organisms particularly abundant in ocean N2O-producing hot spots. Our results provide a mechanistic understanding of N2O production in eukaryotic phototrophs and represent an important step toward a comprehensive assessment of greenhouse gas emission by aquatic ecosystems.

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“…Nevertheless, the NO 2 accumulation, by NO 3 supplied, occurred with and without NH 4 . Furthermore, NO 2 is a product of nitrate reduction within the N assimilation pathway and its concentrations in the cytosol are maintained at a micromolar range to prevent NO 2 toxicity in the cell [42,43]. This ion in addition to being channelled through the ammonium assimilation pathway is capable of being reduced in nitric oxide, which is a by-product of hypoxic N metabolism in the root.…”

Section: Resultsmentioning

confidence: 99%

Tolerance to Nitrogen ions enrichment in a Gulf of Mexico's freshwater submerged grass

Ruiz-Carrera

Sánchez

Leal

2020

Preprint

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BackgroundTolerance to the enrichment of ionic nitrogen (N) with ammonium (NH 4 ) and nitrate (NO 3 ) needs to be distinguished in a submerged grass ecotype-species of freshwater wetlands. Concentrations of total Nitrogen (TN: 500 to 2000 µgL -1 ) and three N sources (NS: NH 4 , NO 3 , 1:1 NH 4 :NO 3 ratio) in an overlaying aqueous phase, using local tap water as control (174 µgL -1 TN), were evaluated in rooted autotrophic juvenile Vallisneria americana established in vitro in two-phase culture medium. The treatments ranged from 7 to 111 µM TN. Phenotypes changes, pH and ionic strength in the aqueous phase were registered at 15 days. In addition, biomass of lyophilized leaf and root as well as N contents (gas and high-performance liquid chromatography) were analysed to estimate accumulations of N-NH 4 , N-NO 3 and N-NO 2 .ResultsAll individuals showed phenotypic similarities. Accumulation of N-NH 4 was discarded, but the accumulations of N-NO 3 and N-NO 2 in both tissues were significantly different (p<0.001 and 0.0001), revealing so much that the maximum cumulative responses coincided with a deficit of N as both showed a linear decrease in their cumulative capacity linked to an increase in micromolar TN. ConclusionsThe results provide direct evidence of the tolerance to N enrichment with three different N sources in the focal ecotype at the seedling stage, based mainly on its cumulative capacity of N-NO 3 and N-NO 2 under eutrophic conditions. The findings imply that NO 2 is a relevant ion in the tolerance to N enrichment in overlaying water with NH 4 and NO 3 ions. Future studies of N cumulative effect with an in vitro approximation will be to support stress predictions by N enrichment. Keywords : Hydrocharitaceae. Eutrophization. Stress in vitro. Ammonium. Nitrate. Nitrogen endogenous

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Role of Nitrate Reductase in NO Production in Photosynthetic Eukaryotes

Cited by 67 publications

References 110 publications

Heterodera schachtii infection affects nitrogen metabolism in Arabidopsis thaliana

Heterodera schachtii infection affects nitrogen metabolism in Arabidopsis thaliana

Algal photosynthesis converts nitric oxide into nitrous oxide

Tolerance to Nitrogen ions enrichment in a Gulf of Mexico's freshwater submerged grass

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