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30 pages, 32945 KiB

Open AccessArticle

Hypoxia-Induced Aquaporins and Regulation of Redox Homeostasis by a Trans-Plasma Membrane Electron Transport System in Maize Roots

by

Anne Hofmann

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Stefanie Wienkoop

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Sabine Lüthje

Antioxidants 2022, 11(5), 836; https://doi.org/10.3390/antiox11050836 - 25 Apr 2022

Cited by 1 | Viewed by 2411

Abstract

In plants, flooding-induced oxygen deficiency causes severe stress, leading to growth reduction and yield loss. It is therefore important to understand the molecular mechanisms for adaptation to hypoxia. Aquaporins at the plasma membrane play a crucial role in water uptake. However, their role [...] Read more.

In plants, flooding-induced oxygen deficiency causes severe stress, leading to growth reduction and yield loss. It is therefore important to understand the molecular mechanisms for adaptation to hypoxia. Aquaporins at the plasma membrane play a crucial role in water uptake. However, their role during hypoxia and membrane redox changes is still not fully understood. The influence of 24 h hypoxia induction on hydroponically grown maize (Zea mays L.) was investigated using an oil-based setup. Analyses of physiological parameters revealed typical flooding symptoms such as increased ethylene and H₂O₂ levels, an increased alcohol dehydrogenase activity, and an increased redox activity at the plasma membrane along with decreased oxygen of the medium. Transcriptomic analysis and shotgun proteomics of plasma membranes and soluble fractions were performed to determine alterations in maize roots. RNA-sequencing data confirmed the upregulation of genes involved in anaerobic metabolism, biosynthesis of the phytohormone ethylene, and its receptors. Transcripts of several antioxidative systems and other oxidoreductases were regulated. Mass spectrometry analysis of the plasma membrane proteome revealed alterations in redox systems and an increased abundance of aquaporins. Here, we discuss the importance of plasma membrane aquaporins and redox systems in hypoxia stress response, including the regulation of plant growth and redox homeostasis. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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18 pages, 3296 KiB

Open AccessArticle

Nitric Oxide (NO) Differentially Modulates the Ascorbate Peroxidase (APX) Isozymes of Sweet Pepper (Capsicum annuum L.) Fruits

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Salvador González-Gordo

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Marta Rodríguez-Ruiz

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Javier López-Jaramillo

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María A. Muñoz-Vargas

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José M. Palma

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Francisco J. Corpas

Antioxidants 2022, 11(4), 765; https://doi.org/10.3390/antiox11040765 - 12 Apr 2022

Cited by 17 | Viewed by 1924

Abstract

Nitric oxide (NO) is a free radical which modulates protein function and gene expression throughout all stages of plant development. Fruit ripening involves a complex scenario where drastic phenotypical and metabolic changes take place. Pepper fruits are one of the most consumed horticultural [...] Read more.

Nitric oxide (NO) is a free radical which modulates protein function and gene expression throughout all stages of plant development. Fruit ripening involves a complex scenario where drastic phenotypical and metabolic changes take place. Pepper fruits are one of the most consumed horticultural products worldwide which, at ripening, undergo crucial phenotypical and biochemical events, with NO and antioxidants being implicated. Based on previous transcriptomic (RNA-Seq), proteomics (iTRAQ), and enzymatic data, this study aimed to identify the ascorbate peroxidase (APX) gene and protein profiles in sweet peppers and to evaluate their potential modulation by NO during fruit ripening. The data show the existence of six CaAPX genes (CaAPX1–CaAPX6) that encode corresponding APX isozymes distributed in cytosol, plastids, mitochondria, and peroxisomes. The time course expression analysis of these genes showed heterogeneous expression patterns throughout the different ripening stages, and also as a consequence of treatment with NO gas. Additionally, six APX isozymes activities (APX I–APX VI) were identified by non-denaturing PAGE, and they were also differentially modulated during maturation and NO treatment. In vitro analyses of fruit samples in the presence of NO donors, peroxynitrite, and glutathione, showed that CaAPX activity was inhibited, thus suggesting that different posttranslational modifications (PTMs), including S-nitrosation, Tyr-nitration, and glutathionylation, respectively, may occur in APX isozymes. In silico analysis of the protein tertiary structure showed that residues Cys32 and Tyr235 were conserved in the six CaAPXs, and are thus likely potential targets for S-nitrosation and nitration, respectively. These data highlight the complex mechanisms of the regulation of APX isozymes during the ripening process of sweet pepper fruits and how NO can exert fine control. This information could be useful for postharvest technology; NO regulates H₂O₂ levels through the different APX isozymes and, consequently, could modulate the shelf life and nutritional quality of pepper fruits. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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18 pages, 3155 KiB

Open AccessArticle

Potassium (K⁺) Starvation-Induced Oxidative Stress Triggers a General Boost of Antioxidant and NADPH-Generating Systems in the Halophyte Cakile maritima

by

Hayet Houmani

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Ahmed Debez

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Larisse de Freitas-Silva

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Chedly Abdelly

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José M. Palma

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Francisco J. Corpas

Antioxidants 2022, 11(2), 401; https://doi.org/10.3390/antiox11020401 - 16 Feb 2022

Cited by 10 | Viewed by 2357

Abstract

Potassium (K⁺) is an essential macro-element for plant growth and development given its implication in major processes such as photosynthesis, osmoregulation, protein synthesis, and enzyme function. Using 30-day-old Cakile maritima plants as halophyte model grown under K⁺ deprivation for 15 [...] Read more.

Potassium (K⁺) is an essential macro-element for plant growth and development given its implication in major processes such as photosynthesis, osmoregulation, protein synthesis, and enzyme function. Using 30-day-old Cakile maritima plants as halophyte model grown under K⁺ deprivation for 15 days, it was analyzed at the biochemical level to determine the metabolism of reactive oxygen species (ROS), key photorespiratory enzymes, and the main NADPH-generating systems. K⁺ starvation-induced oxidative stress was noticed by high malondialdehyde (MDA) content associated with an increase of superoxide radical (O₂^•−) in leaves from K⁺-deficient plants. K⁺ shortage led to an overall increase in the activity of hydroxypyruvate reductase (HPR) and glycolate oxidase (GOX), as well as of antioxidant enzymes catalase (CAT), those of the ascorbate-glutathione cycle, peroxidase (POX), and superoxide dismutase (SOD), and the main enzymes involved in the NADPH generation in both leaves and roots. Especially remarkable was the induction of up to seven CuZn-SOD isozymes in leaves due to K⁺ deficiency. As a whole, data show that the K⁺ starvation has associated oxidative stress that boosts a biochemical response leading to a general increase of the antioxidant and NADPH-generating systems that allow the survival of the halophyte Cakile maritima. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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21 pages, 4079 KiB

Open AccessArticle

Nitric Oxide as a Remedy against Oxidative Damages in Apple Seeds Undergoing Accelerated Ageing

by

Katarzyna Ciacka

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Marcin Tyminski

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Agnieszka Gniazdowska

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Urszula Krasuska

Antioxidants 2022, 11(1), 70; https://doi.org/10.3390/antiox11010070 - 28 Dec 2021

Cited by 4 | Viewed by 1660

Abstract

Seed ageing is associated with a high concentration of reactive oxygen species (ROS). Apple (Malus domestica Borkh.) seeds belong to the orthodox type. Due to a deep dormancy, they may be stored in dry condition at 5 °C for a long time, [...] Read more.

Seed ageing is associated with a high concentration of reactive oxygen species (ROS). Apple (Malus domestica Borkh.) seeds belong to the orthodox type. Due to a deep dormancy, they may be stored in dry condition at 5 °C for a long time, without viability loss. In the laboratory, artificial ageing of apple seeds is performed by imbibition in wet sand at warm temperature (33 °C). The aim of the work was to study nitric oxide (NO) as a seed vigour preservation agent. Embryos isolated from apple seeds subjected to accelerated ageing for 7, 14, 21 or 40 days were fumigated with NO. Embryo quality was estimated by TTC and MDA tests. ROS level was confirmed by NBT staining. We analysed the alteration in transcript levels of CAT, SOD and POX. NO fumigation of embryos of seeds aged for 21 days stimulated germination and increased ROS level which correlated to the elevated expression of RBOH. The increased total antioxidant capacity after NO fumigation was accompanied by the increased transcript levels of genes encoding enzymatic antioxidants, that could protect against ROS overaccumulation. Moreover, post-aged NO application diminished the nitro-oxidative modification of RNA, proving NO action as a remedy in oxidative remodelling after seeds ageing. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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12 pages, 811 KiB

Open AccessArticle

Theoretical and Experimental Considerations for a Rapid and High Throughput Measurement of Catalase In Vitro

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Ouardia Bendou

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Ismael Gutiérrez-Fernández

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Emilio L. Marcos-Barbero

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Nara Bueno-Ramos

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Ana I. González-Hernández

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Rosa Morcuende

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Juan B. Arellano

Antioxidants 2022, 11(1), 21; https://doi.org/10.3390/antiox11010021 - 22 Dec 2021

Cited by 4 | Viewed by 3140

Abstract

A rapid and high throughput protocol to measure the catalase activity in vitro has been designed. Catalase is an enzyme with unusual kinetic properties because it does not follow the standard Michaelis–Menten model and is inactivated by H₂O₂. This [...] Read more.

A rapid and high throughput protocol to measure the catalase activity in vitro has been designed. Catalase is an enzyme with unusual kinetic properties because it does not follow the standard Michaelis–Menten model and is inactivated by H₂O₂. This makes the analysis of the two rate equations of the second-ordered reactions of the kinetic model rather complex. A two-degree polynomial fitting of the experimental data is proposed after transforming the exponential form of the integrated rate equation of the [H₂O₂] into a polynomial using the Taylor series. The fitting is validated by establishing an experimental linear relationship between the initial rate of the H₂O₂ decomposition and the protein concentration, regardless of the suicide inactivation that catalase might undergo beyond t > 0. In addition, experimental considerations are taken into account to avoid statistical bias in the analysis of the catalase activity. ANOVA analyses show that the proposed protocol can be utilized to measure the initial rate of the H₂O₂ decomposition by catalase in 32 samples in triplicates if kept below 8 mM min⁻¹ in the microplate wells. These kinetic and statistical analyses can pave the way for other antioxidant enzyme activity assays in microplate readers at small scale and low cost. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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21 pages, 2055 KiB

Open AccessArticle

Glutathione Is Required for the Early Alert Response and Subsequent Acclimation in Cadmium-Exposed Arabidopsis thaliana Plants

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Antioxidants 2022, 11(1), 6; https://doi.org/10.3390/antiox11010006 - 21 Dec 2021

Cited by 5 | Viewed by 2026

Abstract

Pollution by cadmium (Cd) is a worldwide problem, posing risks to human health and impacting crop yield and quality. Cadmium-induced phytotoxicity arises from an imbalance between antioxidants and pro-oxidants in favour of the latter. The Cd-induced depletion of the major antioxidant glutathione (GSH) [...] Read more.

Pollution by cadmium (Cd) is a worldwide problem, posing risks to human health and impacting crop yield and quality. Cadmium-induced phytotoxicity arises from an imbalance between antioxidants and pro-oxidants in favour of the latter. The Cd-induced depletion of the major antioxidant glutathione (GSH) strongly contributes to this imbalance. Rather than being merely an adverse effect of Cd exposure, the rapid depletion of root GSH levels was proposed to serve as an alert response. This alarm phase is crucial for an optimal stress response, which defines acclimation later on. To obtain a better understanding on the importance of GSH in the course of these responses and how these are defined by the rapid GSH depletion, analyses were performed in the GSH-deficient cadmium-sensitive 2-1 (cad2-1) mutant. Cadmium-induced root and leaf responses related to oxidative challenge, hydrogen peroxide (H₂O₂), GSH, ethylene, and 1-aminocyclopropane-1-carboxylic acid (ACC) were compared between wild-type (WT) and mutant Arabidopsis thaliana plants. Although the cad2-1 mutant has significantly lower GSH levels, root GSH depletion still occurred, suggesting that the chelating capacity of GSH is prioritised over its antioxidative function. We demonstrated that responses related to GSH metabolism and ACC production were accelerated in mutant roots and that stress persisted due to suboptimal acclimation. In general, the redox imbalance in cad2-1 mutant plants and the lack of proper transient ethylene signalling contributed to this suboptimal acclimation, resulting in a more pronounced Cd effect. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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22 pages, 4006 KiB

Open AccessArticle

Spermine-Mediated Tolerance to Selenium Toxicity in Wheat (Triticum aestivum L.) Depends on Endogenous Nitric Oxide Synthesis

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Md. Mahadi Hasan

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Basmah M. Alharbi

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Haifa Abdulaziz Sakit Alhaithloul

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Awatif M. Abdulmajeed

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Suliman Mohammed Alghanem

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Amina A. M. Al-Mushhin

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Antioxidants 2021, 10(11), 1835; https://doi.org/10.3390/antiox10111835 - 19 Nov 2021

Cited by 18 | Viewed by 1976

Abstract

Excess selenium (Se) causes toxicity, and nitric oxide (NO)’s function in spermine (Spm)-induced tolerance to Se stress is unknown. Using wheat plants exposed to 1 mM sodium selenate—alone or in combination with either 1 mM Spm, 0.1 mM NO donor sodium nitroprusside (SNP) [...] Read more.

Excess selenium (Se) causes toxicity, and nitric oxide (NO)’s function in spermine (Spm)-induced tolerance to Se stress is unknown. Using wheat plants exposed to 1 mM sodium selenate—alone or in combination with either 1 mM Spm, 0.1 mM NO donor sodium nitroprusside (SNP) or 0.1 mM NO scavenger cPTIO—the potential beneficial effects of these compounds to palliate Se-induced stress were evaluated at physiological, biochemical and molecular levels. Se-treated plants accumulated Se in their roots (92%) and leaves (95%) more than control plants. Furthermore, Se diminished plant growth, photosynthetic traits and the relative water content and increased the levels of malondialdehyde, H₂O₂, osmolyte and endogenous NO. Exogenous Spm significantly decreased the levels of malondialdehyde by 28%, H₂O₂ by 37% and electrolyte leakage by 42%. Combined Spm/NO treatment reduced the Se content and triggered plant growth, photosynthetic traits, antioxidant enzymes and glyoxalase systems. Spm/NO also upregulated MTP1, MTPC3 and HSP70 and downregulated TaPCS1 and NRAMP1 (metal stress-related genes involved in selenium uptake, translocation and detoxification). However, the positive effects of Spm on Se-stressed plants were eliminated by the NO scavenger. Accordingly, data support the notion that Spm palliates selenium-induced oxidative stress since the induced NO elicits antioxidant defence upregulation but downregulates Se uptake and translocation. These findings pave the way for potential biotechnological approaches to supporting sustainable wheat crop production in selenium-contaminated areas. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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16 pages, 3900 KiB

Open AccessArticle

2-Hydroxymelatonin, Rather Than Melatonin, Is Responsible for RBOH-Dependent Reactive Oxygen Species Production Leading to Premature Senescence in Plants

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Hyoung Yool Lee

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Kyoungwhan Back

Antioxidants 2021, 10(11), 1728; https://doi.org/10.3390/antiox10111728 - 29 Oct 2021

Cited by 15 | Viewed by 1942

Abstract

Unlike animals, plants amply convert melatonin into 2-hydroxymelatonin (2-OHM) and cyclic 3-hydroxymelatonin (3-OHM) through the action of melatonin 2-hydroxylase (M2H) and melatonin 3-hydroxylase (M3H), respectively. Thus, the effects of exogenous melatonin treatment in plants may be caused by melatonin, 2-OHM, or 3-OHM, or [...] Read more.

Unlike animals, plants amply convert melatonin into 2-hydroxymelatonin (2-OHM) and cyclic 3-hydroxymelatonin (3-OHM) through the action of melatonin 2-hydroxylase (M2H) and melatonin 3-hydroxylase (M3H), respectively. Thus, the effects of exogenous melatonin treatment in plants may be caused by melatonin, 2-OHM, or 3-OHM, or some combination of these compounds. Indeed, studies of melatonin’s effects on reactive oxygen species (ROS) production have reported conflicting results. In this study, we demonstrated that 2-OHM treatment induced ROS production, whereas melatonin did not. ROS production from 2-OHM treatment occurred in old arabidopsis leaves in darkness, consistent with an ethylene-mediated senescence mechanism. Transgenic tobacco plants containing overexpressed rice M2H exhibited dwarfism and leaf necrosis of the upper leaves and early senescence of the lower leaves. We also demonstrated that 2-OHM-mediated ROS production is respiratory burst NADPH oxidase (RBOH)-dependent and that 2-OHM-induced senescence genes require ethylene and the abscisic acid (ABA) signaling pathway in arabidopsis. In contrast to melatonin, 2-OHM treatment induced senescence symptoms such as leaf chlorosis and increased ion leakage in arabidopsis. Senescence induction is known to begin with decreased levels of proteins involved in chloroplast maintenance, including Lhcb1 and ClpR1. Together, these results show that 2-OHM acts as a senescence-inducing factor by inducing ROS production in plants. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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24 pages, 16849 KiB

Open AccessArticle

Response to Antimony Toxicity in Dittrichia viscosa Plants: ROS, NO, H₂S, and the Antioxidant System

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Francisco Luis Espinosa-Vellarino

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Antioxidants 2021, 10(11), 1698; https://doi.org/10.3390/antiox10111698 - 27 Oct 2021

Cited by 8 | Viewed by 1742

Abstract

Dittrichia viscosa plants were grown hydroponically with different concentrations of Sb. There was preferential accumulation of Sb in roots. Fe and Cu decreased, while Mn decreased in roots but not in leaves. Chlorophyll content declined, but the carotenoid content increased, and photosynthetic efficiency [...] Read more.

Dittrichia viscosa plants were grown hydroponically with different concentrations of Sb. There was preferential accumulation of Sb in roots. Fe and Cu decreased, while Mn decreased in roots but not in leaves. Chlorophyll content declined, but the carotenoid content increased, and photosynthetic efficiency was unaltered. O₂^●− generation increased slightly, while lipid peroxidation increased only in roots. H₂O₂, NO, ONOO⁻, S-nitrosothiols, and H₂S showed significant increases, and the enzymatic antioxidant system was altered. In roots, superoxide dismutase (SOD) and monodehydroascorbate reductase (MDAR) activities declined, dehydroscorbate reductase (DHAR) rose, and ascorbate peroxidase (APX), peroxidase (POX), and glutathione reductase (GR) were unaffected. In leaves, SOD and POX increased, MDAR decreased, and APX was unaltered, while GR increased. S-nitrosoglutathione reductase (GSNOR) and l-cysteine desulfhydrilase (l-DES) increased in activity, while glutathione S-transferase (GST) decreased in leaves but was enhanced in roots. Components of the AsA/GSH cycle decreased. The great capacity of Dittrichia roots to accumulate Sb is the reason for the differing behaviour observed in the enzymatic antioxidant systems of the two organs. Sb appears to act by binding to thiol groups, which can alter free GSH content and SOD and GST activities. The coniferyl alcohol peroxidase activity increased, possibly to lignify the roots’ cell walls. Sb altered the ROS balance, especially with respect to H₂O₂. This led to an increase in NO and H₂S acting on the antioxidant system to limit that Sb-induced redox imbalance. The interaction NO, H₂S and H₂O₂ appears key to the response to stress induced by Sb. The interaction between ROS, NO, and H₂S appears to be involved in the response to Sb. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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24 pages, 4747 KiB

Open AccessArticle

Peroxisomal PEX7 Receptor Affects Cadmium-Induced ROS and Auxin Homeostasis in Arabidopsis Root System

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Diego Piacentini

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Federica Della Rovere

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Ilaria Bertoldi

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Lorenzo Massimi

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Adriano Sofo

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Maria Maddalena Altamura

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Giuseppina Falasca

Antioxidants 2021, 10(9), 1494; https://doi.org/10.3390/antiox10091494 - 20 Sep 2021

Cited by 9 | Viewed by 2507

Abstract

Peroxisomes are important in plant physiological functions and stress responses. Through the production of reactive oxygen and nitrogen species (ROS and RNS), and antioxidant defense enzymes, peroxisomes control cellular redox homeostasis. Peroxin (PEX) proteins, such as PEX7 and PEX5, recognize peroxisome targeting signals [...] Read more.

Peroxisomes are important in plant physiological functions and stress responses. Through the production of reactive oxygen and nitrogen species (ROS and RNS), and antioxidant defense enzymes, peroxisomes control cellular redox homeostasis. Peroxin (PEX) proteins, such as PEX7 and PEX5, recognize peroxisome targeting signals (PTS1/PTS2) important for transporting proteins from cytosol to peroxisomal matrix. pex7-1 mutant displays reduced PTS2 protein import and altered peroxisomal metabolism. In this research we analyzed the role of PEX7 in the Arabidopsis thaliana root system exposed to 30 or 60 μM CdSO₄. Cd uptake and translocation, indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) levels, and reactive oxygen species (ROS) and reactive nitrogen species (RNS) levels and catalase activity were analyzed in pex7-1 mutant primary and lateral roots in comparison with the wild type (wt). The peroxisomal defect due to PEX7 mutation did not reduce Cd-uptake but reduced its translocation to the shoot and the root cell peroxisomal signal detected by 8-(4-Nitrophenyl) Bodipy (N-BODIPY) probe. The trend of nitric oxide (NO) and peroxynitrite in pex7-1 roots, exposed/not exposed to Cd, was as in wt, with the higher Cd-concentration inducing higher levels of these RNS. By contrast, PEX7 mutation caused changes in Cd-induced hydrogen peroxide (H₂O₂) and superoxide anion (O₂^●−) levels in the roots, delaying ROS-scavenging. Results show that PEX7 is involved in counteracting Cd toxicity in Arabidopsis root system by controlling ROS metabolism and affecting auxin levels. These results add further information to the important role of peroxisomes in plant responses to Cd. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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27 pages, 13711 KiB

Open AccessArticle

Physiological and Biochemical Dissection Reveals a Trade-Off between Antioxidant Capacity and Heat Tolerance in Bread Wheat (Triticum aestivum L.)

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Mohammed Mohi-Ud-Din

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Nurealam Siddiqui

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Motiar Rohman

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S. V. Krishna Jagadish

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Antioxidants 2021, 10(3), 351; https://doi.org/10.3390/antiox10030351 - 26 Feb 2021

Cited by 12 | Viewed by 3870

Abstract

Heat stress alters photosynthetic components and the antioxidant scavenging system, negatively affecting plant growth and development. Plants overcome heat stress damage through an integrated network involving enzymatic and non-enzymatic antioxidants. This study aimed to assess physiological and biochemical responses in contrasting thermo-tolerant wheat [...] Read more.

Heat stress alters photosynthetic components and the antioxidant scavenging system, negatively affecting plant growth and development. Plants overcome heat stress damage through an integrated network involving enzymatic and non-enzymatic antioxidants. This study aimed to assess physiological and biochemical responses in contrasting thermo-tolerant wheat varieties exposed to 25 °C (control) and 35 °C (heat stress), during the seedling stage. Our results revealed a substantial decrease in the photosynthetic pigments, carotenoids, anthocyanin content, and increased membrane injury index, malondialdehyde, methylglyoxal (MG), H₂O₂ contents and lipoxygenase activity compared to non-stress wheat seedlings. The heat-tolerant variety BARI Gom 26 (“BG26”) maintained higher cellular homeostasis compared to the heat susceptible variety Pavon 76 (“Pavon”), perpetuated by higher accumulation of proline, glycine betaine, ascorbate-glutathione cycle associated enzymes, reduced glutathione and ascorbate concentration in plant cells. Significantly lower levels of MG detoxification and antioxidant activities and ascorbate-glutathione cycle-related enzymatic activities lead to increased susceptibility in variety “Pavon”. Hierarchical clustering and principal component analysis revealed that variety “BG26” possess a combination of biochemical responses tailoring antioxidant activities that induced a higher level of tolerance. Taken together, our results provide a pipeline for establishing a trade-off between antioxidant capacity and heat tolerance to facilitate functional genomics and translational research to unravel underlying mechanisms to better adapt wheat to heat stress. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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20 pages, 2192 KiB

Open AccessArticle

Nitric Oxide and Hydrogen Sulfide Coordinately Reduce Glucose Sensitivity and Decrease Oxidative Stress via Ascorbate-Glutathione Cycle in Heat-Stressed Wheat (Triticum aestivum L.) Plants

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Antioxidants 2021, 10(1), 108; https://doi.org/10.3390/antiox10010108 - 14 Jan 2021

Cited by 61 | Viewed by 4349

Abstract

The involvement of nitric oxide (NO) and hydrogen sulfide (H₂S) in countermanding heat-inhibited photosynthetic features were studied in wheat (Triticum aestivum L.). Heat stress (HS) was employed at 40 °C after establishment for 6 h daily, and then plants were [...] Read more.

The involvement of nitric oxide (NO) and hydrogen sulfide (H₂S) in countermanding heat-inhibited photosynthetic features were studied in wheat (Triticum aestivum L.). Heat stress (HS) was employed at 40 °C after establishment for 6 h daily, and then plants were allowed to recover at 25 °C and grown for 30 days. Glucose (Glc) content increased under HS and repressed plant photosynthetic ability, but the application of sodium nitroprusside (SNP, as NO donor) either alone or with sodium hydrosulfide (NaHS, as H₂S donor) reduced Glc-mediated photosynthetic suppression by enhancing ascorbate-glutathione (AsA-GSH) metabolism and antioxidant system, which reduced oxidative stress with decreased H₂O₂ and TBARS content. Oxidative stress reduction or inhibiting Glc repression was maximum with combined SNP and NaHS treatment, which was substantiated by 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) and hypotaurine (HT), scavengers for NO and H₂S, respectively. The scavenge of H₂S reduced NO-mediated alleviation of HS suggesting of its downstream action in NO-mediated heat-tolerance. However, a simultaneous decrease of both (NO and H₂S) led to higher Glc-mediated repression of photosynthesis and oxidative stress in terms of increased H₂O₂ content that was comparable to HS plants. Thus, NO and H₂S cooperate to enhance photosynthesis under HS by reducing H₂O₂-induced oxidative stress and excess Glc-mediated photosynthetic suppression. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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18 pages, 20154 KiB

Open AccessArticle

The Effect of Foliar Selenium (Se) Treatment on Growth, Photosynthesis, and Oxidative-Nitrosative Signalling of Stevia rebaudiana Leaves

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Antioxidants 2021, 10(1), 72; https://doi.org/10.3390/antiox10010072 - 08 Jan 2021

Cited by 15 | Viewed by 2859

Abstract

Selenium (Se) enrichment of Stevia rebaudiana Bertoni can serve a dual purpose, on the one hand to increase plant biomass and stress tolerance and on the other hand to produce Se fortified plant-based food. Foliar Se spraying (0, 6, 8, 10 mg/L selenate, [...] Read more.

Selenium (Se) enrichment of Stevia rebaudiana Bertoni can serve a dual purpose, on the one hand to increase plant biomass and stress tolerance and on the other hand to produce Se fortified plant-based food. Foliar Se spraying (0, 6, 8, 10 mg/L selenate, 14 days) of Stevia plantlets resulted in slightly decreased stevioside and rebaudioside A concentrations, and it also caused significant increment in stem elongation, leaf number, and Se content, suggesting that foliar Se supplementation can be used as a biofortifying approach. Furthermore, Se slightly limited photosynthetic CO₂ assimilation (A_N, g_sw, C_i/C_a), but exerted no significant effect on chlorophyll, carotenoid contents and on parameters associated with photosystem II (PSII) activity (F_V/F_M, F₀, Y(NO)), indicating that Se causes no photodamage in PSII. Further results indicate that Se is able to activate PSI-cyclic electron flow independent protection mechanisms of the photosynthetic apparatus of Stevia plants. The applied Se activated superoxide dismutase (SOD) isoenzymes (MnSOD1, FeSOD1, FeSOD2, Cu/ZnSOD1, Cu/ZnSOD2) and down-regulated NADPH oxidase suggesting the Se-induced limitation of superoxide anion levels and consequent oxidative signalling in Stevia leaves. Additionally, the decrease in S-nitrosoglutathione reductase protein abundance and the intensification of protein tyrosine nitration indicate Se-triggered nitrosative signalling. Collectively, these results suggest that Se supplementation alters Stevia shoot morphology without significantly affecting biomass yield and photosynthesis, but increasing Se content and performing antioxidant effects, which indicates that foliar application of Se may be a promising method in Stevia cultivation. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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24 pages, 3561 KiB

Open AccessArticle

Investigation of an Antioxidative System for Salinity Tolerance in Oenanthe javanica

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Antioxidants 2020, 9(10), 940; https://doi.org/10.3390/antiox9100940 - 01 Oct 2020

Cited by 28 | Viewed by 3087

Abstract

Abiotic stress, such as drought and salinity, severely affect the growth and yield of many plants. Oenanthe javanica (commonly known as water dropwort) is an important vegetable that is grown in the saline-alkali soils of East Asia, where salinity is the limiting environmental [...] Read more.

Abiotic stress, such as drought and salinity, severely affect the growth and yield of many plants. Oenanthe javanica (commonly known as water dropwort) is an important vegetable that is grown in the saline-alkali soils of East Asia, where salinity is the limiting environmental factor. To study the defense mechanism of salt stress responses in water dropwort, we studied two water dropwort cultivars, V11E0022 and V11E0135, based on phenotypic and physiological indexes. We found that V11E0022 were tolerant to salt stress, as a result of good antioxidant defense system in the form of osmolyte (proline), antioxidants (polyphenols and flavonoids), and antioxidant enzymes (APX and CAT), which provided novel insights for salt-tolerant mechanisms. Then, a comparative transcriptomic analysis was conducted, and Gene Ontology (GO) analysis revealed that differentially expressed genes (DEGs) involved in the carbohydrate metabolic process could reduce oxidative stress and enhance energy production that can help in adaptation against salt stress. Similarly, lipid metabolic processes can also enhance tolerance against salt stress by reducing the transpiration rate, H₂O₂, and oxidative stress. Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEGs involved in hormone signals transduction pathway promoted the activities of antioxidant enzymes and reduced oxidative stress; likewise, arginine and proline metabolism, and flavonoid pathways also stimulated the biosynthesis of proline and flavonoids, respectively, in response to salt stress. Moreover, transcription factors (TFs) were also identified, which play an important role in salt stress tolerance of water dropwort. The finding of this study will be helpful for crop improvement under salt stress. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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13 pages, 1807 KiB

Open AccessArticle

Different Nitro-Oxidative Response of Odontarrhena lesbiaca Plants from Geographically Separated Habitats to Excess Nickel

by

Gábor Feigl

,

Viktória Varga

,

Árpád Molnár

,

Panayiotis G. Dimitrakopoulos

and

Zsuzsanna Kolbert

Antioxidants 2020, 9(9), 837; https://doi.org/10.3390/antiox9090837 - 07 Sep 2020

Cited by 5 | Viewed by 2262

Abstract

Odontarrhena lesbiaca is an endemic species to the serpentine soils of Lesbos Island (Greece). As a nickel (Ni) hyperaccumulator, it possesses an exceptional Ni tolerance; and it can accumulate up to 0.2–2.4% Ni of its leaves’ dry weight. In our study, O. lesbiaca [...] Read more.

Odontarrhena lesbiaca is an endemic species to the serpentine soils of Lesbos Island (Greece). As a nickel (Ni) hyperaccumulator, it possesses an exceptional Ni tolerance; and it can accumulate up to 0.2–2.4% Ni of its leaves’ dry weight. In our study, O. lesbiaca seeds from two geographically separated study sites (Ampeliko and Loutra) were germinated and grown on control and Ni-containing (3000 mg/kg) soil in a rhizotron system. Ni excess induced significant Ni uptake and translocation in both O. lesbiaca ecotypes and affected their root architecture differently: plants from the Ampeliko site proved to be more tolerant; since their root growth was less inhibited compared to plants originated from the Loutra site. In the roots of the Ampeliko ecotype nitric oxide (NO) was being accumulated, while the degree of protein tyrosine nitration decreased; suggesting that NO in this case acts as a signaling molecule. Moreover, the detected decrease in protein tyrosine nitration may serve as an indicator of this ecotype’s better relative tolerance compared to the more sensitive plants originated from Loutra. Results suggest that Ni hypertolerance and the ability of hyperaccumulation might be connected to the plants’ capability of maintaining their nitrosative balance; yet, relatively little is known about the relationship between excess Ni, tolerance mechanisms and the balance of reactive nitrogen species in plants so far. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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Review

Jump to: Research

9 pages, 11298 KiB

Open AccessReview

The Modus Operandi of Hydrogen Sulfide(H₂S)-Dependent Protein Persulfidation in Higher Plants

by

Francisco J. Corpas

,

Salvador González-Gordo

,

María A. Muñoz-Vargas

,

Marta Rodríguez-Ruiz

and

José M. Palma

Antioxidants 2021, 10(11), 1686; https://doi.org/10.3390/antiox10111686 - 26 Oct 2021

Cited by 10 | Viewed by 2015

Abstract

Protein persulfidation is a post-translational modification (PTM) mediated by hydrogen sulfide (H₂S), which affects the thiol group of cysteine residues from target proteins and can have a positive, negative or zero impact on protein function. Due to advances in proteomic techniques, [...] Read more.

Protein persulfidation is a post-translational modification (PTM) mediated by hydrogen sulfide (H₂S), which affects the thiol group of cysteine residues from target proteins and can have a positive, negative or zero impact on protein function. Due to advances in proteomic techniques, the number of potential protein targets identified in higher plants, which are affected by this PTM, has increased considerably. However, its precise impact on biological function needs to be evaluated at the experimental level in purified proteins in order to identify the specific cysteine(s) residue(s) affected. It also needs to be evaluated at the cellular redox level given the potential interactions among different oxidative post-translational modifications (oxiPTMs), such as S-nitrosation, glutathionylation, sulfenylation, S-cyanylation and S-acylation, which also affect thiol groups. This review aims to provide an updated and comprehensive overview of the important physiological role exerted by persulfidation in higher plants, which acts as a cellular mechanism of protein protection against irreversible oxidation. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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23 pages, 12197 KiB

Open AccessReview

ROS Metabolism Perturbation as an Element of Mode of Action of Allelochemicals

by

Pawel Staszek

,

Urszula Krasuska

,

Katarzyna Ciacka

and

Agnieszka Gniazdowska

Antioxidants 2021, 10(11), 1648; https://doi.org/10.3390/antiox10111648 - 20 Oct 2021

Cited by 18 | Viewed by 2095

Abstract

The allelopathic interaction between plants is one of the elements that influences plant communities. It has been commonly studied by applying tissue extracts onto the acceptors or by treating them with isolated allelotoxins. Despite descriptive observations useful for agricultural practice, data describing the [...] Read more.

The allelopathic interaction between plants is one of the elements that influences plant communities. It has been commonly studied by applying tissue extracts onto the acceptors or by treating them with isolated allelotoxins. Despite descriptive observations useful for agricultural practice, data describing the molecular mode of action of allelotoxins cannot be found. Due to the development of -omic techniques, we have an opportunity to investigate specific reactive oxygen species (ROS)-dependent changes in proteome or transcriptome that are induced by allelochemicals. The aim of our review is to summarize data on the ROS-induced modification in acceptor plants in response to allelopathic plants or isolated allelochemicals. We present the idea of how ROS are involved in the hormesis and plant autotoxicity phenomena. As an example of an -omic approach in studies of the mode of action of allelopatic compounds, we describe the influence of meta-tyrosine, an allelochemical exudated from roots of fescues, on nitration—one of nitro-oxidative posttranslational protein modification in the roots of tomato plants. We conclude that ROS overproduction and an induction of oxidative stress are general plants’ responses to various allelochemicals, thus modification in ROS metabolisms is regarded as an indirect mode of action of allelochemicals. Full article

(This article belongs to the Special Issue Metabolic Networks and Signaling by ROS, RNS and RSS in Higher Plants)

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