Nitric oxide evolution and perception. J Exp Bot

Centre for Research in Plant Science, Faculty of Applied Sciences, University of the West of England, Bristol, Bristol BS16 1Q, UK.
Journal of Experimental Botany (Impact Factor: 5.53). 02/2008; 59(1):25-35. DOI: 10.1093/jxb/erm218
Source: PubMed


Various experimental data indicate signalling roles for nitric oxide (NO) in processes such as xylogenesis, programmed cell death, pathogen defence, flowering, stomatal closure, and gravitropism. However, it still remains unclear how NO is synthesized. Nitric oxide synthase-like activity has been measured in various plant extracts, NO can be generated from nitrite via nitrate reductase and other mechanisms of NO generation are also likely to exist. NO removal mechanisms, for example, by reaction with haemoglobins, have also been identified. NO is a gas emitted by plants, with the rate of evolution increasing under conditions such as pathogen challenge or hypoxia. However, exactly how NO evolution relates to its bioactivity in planta remains to be established. NO has both aqueous and lipid solubility, but is relatively reactive and easily oxidized to other nitrogen oxides. It reacts with superoxide to form peroxynitrite, with other cellular components such as transition metals and haem-containing proteins and with thiol groups to form S-nitrosothiols. Thus, diffusion of NO within the plant may be relatively restricted and there might exist 'NO hot-spots' depending on the sites of NO generation and the local biochemical micro-environment. Alternatively, it is possible that NO is transported as chemical precursors such as nitrite or as nitrosothiols that might function as NO reservoirs. Cellular perception of NO may occur through its reaction with biologically active molecules that could function as 'NO-sensors'. These might include either haem-containing proteins such as guanylyl cyclase which generates the second messenger cGMP or other proteins containing exposed reactive thiol groups. Protein S-nitrosylation alters protein conformation, is reversible and thus, is likely to be of biological significance.

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Available from: John T Hancock, Mar 16, 2015
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    • "Overproduction of ROS and RNS can cause severe oxidative and nitrosative damage, respectively (del Río, 2011). However, ROS and RNS can also act as signalling molecules that regulate developmental processes and stress responses (Neill et al., 2008; Mittler et al., 2011). Peroxisomes can also play an important role in cellular redox homeostasis, which is, in turn, a key element in the regulation of cell metabolic pathways (Foyer and Noctor, 2003; Yun et al., 2012). "
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    ABSTRACT: Peroxisomes are highly dynamic, metabolically active organelles that used to be regarded as a sink for H2O2 generated in different organelles. However, peroxisomes are now considered to have a more complex function, containing different metabolic pathways, and they are an important source of reactive oxygen species (ROS), nitric oxide (NO) and reactive nitrogen species (RNS). Over-accumulation of ROS and RNS can give rise oxidative and nitrosative stress, but when produced at low concentrations they can act as signalling molecules. This review focuses on the production of ROS and RNS in peroxisomes and their regulation by antioxidants. ROS production is associated with metabolic pathways such as photorespiration and fatty acid β-oxidation, and disturbances in any of these processes can be perceived by the cell as an alarm that triggers defence responses. Genetic and pharmacological studies have shown that photorespiratory H2O2 can affect nuclear gene expression, regulating the response to pathogen infection and light intensity. Proteomic studies have shown that peroxisomal proteins are targets for oxidative modification, S-nitrosylation and nitration and have highlighted the importance of these modifications in regulating peroxisomal metabolism and signalling networks. The morphology, size, number and speed of movement of peroxisomes can also change in response to oxidative stress, meaning that an ROS/redox receptor is required. Information available on the production and detection of NO/RNS in peroxisomes is more limited. Peroxisomal homeostasis is critical for maintaining the cellular redox balance and is regulated by ROS, peroxisomal proteases and autophagic processes. Peroxisomes play a key role in many aspects of plant development and acclimation to stress conditions. These organelles can sense ROS/redox changes in the cell and thus trigger rapid and specific responses to environmental cues involving changes in peroxisomal dynamics as well as ROS- and NO-dependent signalling networks, although the mechanisms involved have not yet been established. Peroxisomes can therefore be regarded as a highly important decision-making platform in the cell, where ROS and RNS play a determining role. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email:
    Full-text · Article · Jun 2015 · Annals of Botany
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    • "Nitric oxide (NO) is a key player in redox signaling pathways in plant cell revealing concentration-dependent effects—from the mild regulation of morphogenesis to the triggering of the programmed cell death (PCD) events (Neill et al., 2008; Baudouin, 2011). Dinitrogen trioxide (N 2 O 3 ), nitrogen dioxide (NO 2 ), and highly reactive molecule of nitrogen monoxide (NO) that exist in cell in three interchangeable forms [nitrosonium cation (NO + ), nitroxyl anion (NO − ) and free radical (NO • )] along with peroxynitrite (ONOO − ) and S-nitrosothiols (GSNOs) are named reactive nitrogen species (RNS) (Neill et al., 2008). RNS are able to modify numerous proteins affecting their structure, protein–protein interaction and/or function ( " loss " / " gain " and the enhanced protein turnover) (Lindermayr et al., 2005; Abello et al., 2009). "
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    ABSTRACT: During last years, selective tyrosine nitration of plant proteins gains importance as well-recognized pathway of direct nitric oxide (NO) signal transduction. Plant microtubules are one of the intracellular signaling targets for NO, however, the molecular mechanisms of NO signal transduction with the involvement of cytoskeletal proteins remain to be elucidated. Since biochemical evidence of plant α-tubulin tyrosine nitration has been obtained recently, potential role of this posttranslational modification in regulation of microtubules organization in plant cell is estimated in current paper. It was shown that 3-nitrotyrosine (3-NO2-Tyr) induced partially reversible Arabidopsis primary root growth inhibition, alterations of root hairs morphology and organization of microtubules in root cells. It was also revealed that 3-NO2-Tyr intensively decorates such highly dynamic microtubular arrays as preprophase bands, mitotic spindles and phragmoplasts of Nicotiana tabacum Bright Yellow-2 (BY-2) cells under physiological conditions. Moreover, 3D models of the mitotic kinesin-8 complexes with the tail of detyrosinated, tyrosinated and tyrosine nitrated α-tubulin (on C-terminal Tyr 450 residue) from Arabidopsis were reconstructed in silico to investigate the potential influence of tubulin nitrotyrosination on the molecular dynamics of α-tubulin and kinesin-8 interaction. Generally, presented data suggest that plant α-tubulin tyrosine nitration can be considered as its common posttranslational modification, the direct mechanism of NO signal transduction with the participation of microtubules under physiological conditions and one of the hallmarks of the increased microtubule dynamics.
    Full-text · Article · Dec 2013 · Frontiers in Plant Science
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    • "However, despite decades of research (Vessey and Waterer 1992), the mechanism of nitrate's impact on the activity of existing nodules is not fully understood and remains controversial as there are several competing theories. The nitrate ion itself, nitrite, or nitric oxide has been implicated by either blocking leghemoglobin (Kato et al., 2010) or by triggering a regulatory network at the gene expression level (Neill et al., 2008;Wilson et al., 2008;Meilhoc et al., 2011). A further hypothesis is that the effect of nitrate on legume nodules is mediated by a closure of the oxygen diffusion barrier or a reduction in oxygen permeability facilitated by unspecified mechanisms (Vessey andWaterer, 1992;Minchin, 1997). "
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    ABSTRACT: The mechanism through which nitrate reduces the activity of legume nodules is controversial. The objective of the study was to follow Medicago truncatula nodule activity after nitrate provision continuously and to identify molecular mechanisms which down-regulate the activity of the nodules. Nodule H2 evolution started to decline after about 4 h of nitrate application. At that point in time, a strong shift in nodule gene expression (RNA-seq) had occurred (1120 differentially expressed genes). The most pronounced effect was the down-regulation of 127 genes for nodule-specific cysteine-rich peptides (NCRs). Various other nodulins were also strongly down-regulated, in particular all the genes for leghemoglobins. Shifts in the expression of genes involved in cellular iron allocation and mitochondrial ATP synthesis were observed, too. Furthermore, the expression of numerous genes for the formation of proteins and glycoproteins with no obvious function in nodules (e.g. germins, patatin and thaumatin) was strongly increased. This occurred in conjunction with an up-regulation of genes for proteinase inhibitors, in particular those containing the Kunitz domain. The additionally formed proteins might possibly be involved in reducing nodule oxygen permeability. Between 4 and 28 h of nitrate exposure, a further reduction in nodule activity occurred and the number of differentially expressed genes almost tripled. In particular, there was a differential expression of genes connected with emerging senescence. It is concluded that nitrate exerts rapid and manifold effects on nitrogenase activity. A certain degree of nitrate tolerance might be achieved when the down-regulatory effect on the late nodulins can be alleviated.
    Full-text · Article · Nov 2013 · Plant physiology
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