Enhancement Of Antioxidant System Research Articles

The role and mechanism of Bacillus megaterium strain A14 in inhibiting the cadmium uptake by peanut plants in acidic red soil.

This study explores the potential of Cd-resistant bacteria, specifically Bacillus megaterium A14, to decrease Cd accumulation in peanuts, a crop susceptible to metal uptake from contaminated soils, by understanding the bacterium's impact on plant Cd absorption mechanisms. Through pot experiments, we observed that A14 inoculation significantly increased peanut biomass under Cd stress conditions, primarily by immobilizing the metal and reducing its bioavailability. The bacterium effectively changed the distribution of Cd, with a notable 46.53% reduction in the exchangeable fraction, which in turn limited the expression of genes related to Cd transport in peanuts. Additionally, A14 enhanced the plant's antioxidant response, improving its tolerance to stress. Microbial analysis through 16S sequencing demonstrated that A14 inoculation altered the peanut rhizosphere, particularly by increasing populations of Firmicutes and Proteobacteria, which play crucial roles in soil remediation from heavy metals. The A14 strain effectively counters Cd toxicity in peanuts, promoting growth through soil Cd sequestration, root barrier biofilm formation, antioxidant system enhancement, suppression of Cd transport genes, and facilitation of Cd-remediating microorganisms.

Understanding of effect and mechanism of abiotic stress tolerance in legumes and recent development

The present changing climatic conditions are affecting crop productivity worldwide. The crop growth and productivity are adversely hit by perturbed climatic conditions and climate change. Being sessile, plants are openly exposed to biotic and abiotic stresses which limit the crop productivity. Crop plants exhibit tolerance and susceptibility under adverse conditions through various attributes at different levels like morphological, physiological, biochemical and genetic level, although their magnitude of response varies. Crops responses toward abiotic stresses have increased in the recent years by advancement of technology and understanding of physiology, molecular and genetic level of crops response to these stresses. In the processes of development of stress-tolerant plants, several genes associated tolerance and adaptation get activated leading to modulate several biochemical, physiological and metabolic pathways. Stress also induces the production of reactive oxygen species (ROS) and subsequently change in signal transduction in the plants switches towards enhancement of antioxidant system. Both abiotic and biotic stresses affect all the physiological processes of the legume plants, especially photosynthesis, respiration, water use efficiency, nutrient use efficiency etc. The activity of cell organelles like mitochondria, chloroplast and vacuoles is also affected by stress. The present study is focusing on the impact of diverse abiotic stresses at different levels in legume crops and changes at physiological, biochemical and molecular level. It also discusses the opportunities to ameliorate the ability of the legumes to enhance abiotic stress tolerance for crop improvement and agriculture sustainability.

GABA Application Enhances Drought Stress Tolerance in Wheat Seedlings (Triticum aestivum L.).

In this study, the effects of γ-aminobutyric acid (GABA) on physio-biochemical metabolism, phenolic acid accumulation, and antioxidant system enhancement in germinated wheat under drought stress was investigated. The results showed that exogenous GABA reduced the oxidative damage in wheat seedlings caused by drought stress and enhanced the content of phenolics, with 1.0 mM being the most effective concentration. Six phenolic acids were detected in bound form, including p-hydroxybenzoic acid, vanillic acid, syringic acid, p-coumaric acid, ferulic acid, and sinapic acid. However, only syringic acid and p-coumaric acid were found in free form. A total of 1.0 mM of GABA enhanced the content of total phenolic acids by 28% and 22%, respectively, compared with that of drought stress, on day four and day six of germination. The activities of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H) and 4-coumarate coenzyme A ligase (4CL) were activated by drought stress plus GABA treatment. Antioxidant enzyme activities were also induced. These results indicate that GABA treatment may be an effective way to relieve drought stress as it activates the antioxidant system of plants by inducing the accumulation of phenolics and the increase in antioxidant enzyme activity.

Plant Growth Promoting Microbes as Biofertilizers: Promising solutions for sustainable agriculture under climate change associated abiotic stresses

Abiotic stresses are major constraints for plant growth, crop yield and global food security. Plant physiological, biochemical and molecular processes are highly affected under unfavorable environmental conditions, resulting in substantial losses to crop productivity and requiring an immediate response. Abiotic stress resistant plant growth-promoting rhizobacteria (PGPR) are a profitable and sustainable solution because of their efficiency in plant growth regulation, crop yield improvement and abiotic stress alleviation. They help plants to cope with growth inhibitory effects of abiotic stresses through several mechanisms, mainly phytohormones and osmolyte production, improvement of nutrient acquisition, enhancement of antioxidant system. Plant-PGPR interactions are vital for sustainable agriculture and industrial purposes, because they are based on biological processes and replace conventional agricultural practices. PGPR may play a key role as an ecological engineer to solve environmental stress problems. The use of microbes is a feasible and potential technology to help meeting the future global food needs with reduced impact on soil and environmental quality. Present review deals about the abiotic stresses (drought and salinity) affecting plant growth and highlights the impact of PGPR on restoration of plant growth under the stressful conditions with the goal of developing an eco-friendly and cost-effective strategy for agricultural sustainability.

Identification of Isthmin1 in the small annual fish, Nothobranchius guentheri, as a novel biomarker of aging and its potential rejuvenation activity.

Isthmin 1 (Ism1) has been shown to play roles in multiple biological processes including morphogenesis, hematopoiesis, antiviral immune response and suppression of tumor growth. However, it remains unknown if it plays any role in aging process. Here we showed for the first time that Ism1 was a new age-related biomarker, which decreased with age in fish, mice and humans. Interestingly, Ism1 was also useful to measure the "rejuvenated" age of fish Nothobranchius guentheri reversed by salidroside treatment and temperature reduction, providing additional evidence that Ism1 was an aging biomarker. In addition, we clearly showed that dietary intake of recombinant Ism1 had little effects on the body length and weight of aging N. guentheri, but it retarded the onset of age-related biomarkers and prolonged both the maximum and median lifespan of the fish. We also showed that Ism1 exerted its rejuvenation activity via the enhancement of antioxidant system. Collectively, our results indicate that Ism1 is not only is a novel biomarker of aging but also a potential rejuvenation factor capable of reversing aging of N. guentheri.

UV-B treatment enhances phenolic acids accumulation and antioxidant capacity of barley seedlings

The effects of ultraviolet B (UV-B, 280–315 nm) on phenolic acids content, key enzymes activity and antioxidant capacity as well as the related gene expressions of barley seedlings were investigated in the present study. Results showed that UV-B treatment increased phenolics content including vanillic acid, p-coumaric acid, ferulic acid and erucic acid in barley seedlings, significantly. The mRNA levels and activities of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), 4-coumarate coenzyme A ligase (4CL), p-coumaric acid 3-hdroxylase (C3H), caffeic acid O-methyltransferase (COMT) and ferulic acid 5-hydroxylase (F5H) involved in phenolic acid synthesis increased under UV-B treatment as well. In addition, UV-B radiation enhanced the antioxidant enzymes activity and the gene expressions of barley seedlings, including superoxide dismutase (SOD), peroxidase (POD) and glutathione reductase (GR), and improved 2,2-diazo-bis (3-ethyl-benzothiazole-6-sulfonic acid) diammonium salt (ABTS) and 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radical scavenging ability. In conclusion, UV-B treatment led to the upper-regulation of related enzymes activity and gene expression, resulting in the accumulation of phenolic acids in barley seedlings, thus contributing to the enhancement of antioxidant system.

Spirulina supplementation as an adjuvant therapy in enhancement of antioxidant capacity: A systematic review and meta-analysis of controlled clinical trials.

Spirulina, a type of blue-green algae, is used as an adjuvant treatment of metabolic and inflammatory diseases. Evidence about the effects of spirulina on antioxidant system are conflicting. Thus, this quantitative review aimed to summarise the effects of spirulina administration on antioxidant status biomarkers. Systematic searches were conducted using the PubMed/Medline, Scopus, Web of Science and EMBASE, up to May 2021. Random effect analysis was applied to perform meta-analysis. Subgroup analyses and multivariate meta-regression were performed to find heterogeneity sources. Quality assessment was conducted using Cochrane Collaboration's tool. Trim and fill analysis were also carried out in case of the presence of publication bias. A total of nine articles that enrolled 415 subjects were included in the present meta-analysis. Obtained findings exhibited that spirulina supplementation had marginal significant effect on total antioxidant capacity (TAC) (SMD=0.49; 95% CI: -0.001, 0.98; P=.05) and superoxide dismutase (SOD) activity (SMD=0.72; 95% CI: -0.03, 1.46; P=.06), while did not affect glutathione peroxidase (GPx) activity (SMD=0.27; 95% CI: -0.23, 0.77; P=.29). Spirulina consumption may exert beneficial effects on enhancement of antioxidant system. A marginal significant increasing effect on TAC and SOD activity were found by spirulina administration. However, it did not affect GPx activity.

GABA Regulates Phenolics Accumulation in Soybean Sprouts under NaCl Stress.

NaCl stress causes oxidative stress in plants; γ-aminobutyric acid (GABA) could alleviate such abiotic stress by enhancing the synthesis of phenolics, but the underlying mechanism is not clear. We investigated the effects of GABA on phenolics accumulation in soybean sprouts under NaCl stress by measuring changes in the content of physiological biochemicals and phenolic substances, in the activity and gene expression of key enzymes, and in antioxidant capacity. GABA reduced the oxidative damage in soybean sprouts caused by NaCl stress and enhanced the content of total phenolics, phenolic acids, and isoflavones by 16.58%, 22.47%, and 3.75%, respectively. It also increased the activities and expression of phenylalanine ammonia lyase, cinnamic acid 4-hydroxylase, and 4-coumarate coenzyme A ligase. Furthermore, GABA increased the activity of antioxidant enzymes and the antioxidant capacity. These events were inhibited by 3-mercaptopropionate (an inhibitor for GABA synthesis), indicating that GABA mediated phenolics accumulation and antioxidant system enhancement in soybean sprouts under NaCl stress.

Postharvest application of glycine betaine ameliorates chilling injury in cold-stored banana fruit by enhancing antioxidant system

Chilling injury (CI) represents a physiological disorder caused by improper low temperature management, which affects the postharvest quality and marketing potential of banana fruit. In this study, postharvest application of glycine betaine (GB) can significantly reduce the CI incidence of banana fruit during cold storage, as observed by lower CI index, electrolyte leakage, malondialdehyde (MDA) contents, and higher values of lightness, chlorophyll, soluble sugar contents. Moreover, GB not only increased the antioxidant substances such as total phenolics, glutathione and ascorbic acids (AsA), but also elevated the enzyme activities and gene expression of the antioxidant enzymes including ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD). In addition, GB could obviously enhance the total antioxidant capacity of banana fruit under refrigerated storage. Collectively, these findings suggest that GB-attenuated CI incidence in banana fruit during cold storage might be, at least partially, ascribed to the enhancement of antioxidant system involving antioxidant substances, as well as enzyme activities and gene expression of antioxidant enzymes.

Sidr honey abrogates the oxidative stress and downregulates the hyaluronic acid concentration and gene expression of TGF-β1 and COL1a1 in rat model of thioacetamide-induced hepatic fibrosis.

Liver fibrosis is a major health concern, which might progress to cirrhosis. To date, treatment trials rely mainly on the removal of the causative factor. The current study investigated the potential ameliorative role of sidr honey on thioacetamide (TAA)-induced liver fibrosis in rats. Forty-eight Wistar albino rats were equally allocated into four groups: control;sidr honey (5g/kg body weight (BW), orally); TAA (200mg/kgBW,IP three timesweekly/15weeks);andsidr honeyplusTAA at the same dose and administration rout. Rats co-treated with sidr honeyplusTAA revealed significant reduction in hepatic malondialdehyde, hyaluronic acid (HA), alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma glutamyl transferase, direct bilirubin, and hepatic mRNA expression of transforming growth factor (TGF)-β1 and collagen type I alpha 1 chain (COL1a1) compared to TAA-exposed rats. In addition, the hepatoprotective potential of sidr honey was indicated via improvement of histopathologic picture of hepatocytes and upregulation of total antioxidant capacity, reduced glutathione, catalase, glutathione peroxidase, superoxide dismutase, total protein, and albumin compared to TAA-treated rats. In conclusion, daily administration of sidr honey (5g/kg BW) is a promising natural antioxidant and fibrosuppressiveagent that could ameliorate liver fibrosis via downregulation of fibrosis genes including TGF-β1 and COL1a1 and HA and via enhancement of antioxidant system.

Nanosized selenium and Loranthus micranthus leaves ameliorate streptozotocin-induced hepato-renal dysfunction in rats via enhancement of antioxidant system, regulation of caspase 3 and Nrf2 protein expression

The investigation of potential health benefits of nano-sized nutriceuticals is recently a major scientific interest. The present study investigated the effect of Selenium and Loranthus micranthus leaves nanoparticles (SeNPs and LMLNPs), on streptozotocin (STZ)-diabetes induced hepato-renal dysfunction in rats. Adult rats were rendered diabetic by a single i.p exposure to 40 mg/kg STZ. Thereafter, rats were treated with 0.1 mg/kg SeNPs or 200 mg/kg LMLNPs, or a combination of both, while 50 mg/kg metformin was used as a standard therapeutic drug. Results indicated that STZ-diabetic rats experienced liver and kidney damage evidenced by a significant elevation in serum activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and 5′ nucleotidase (5′NT) when compared to non-diabetic control rats. Furthermore, a decrease in activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), Glutathione-S-transferase (GST) and glutathione (GSH) levels was observed, whereas myeloperoxidase (MPO) activities and lipid peroxidation (LPO) levels increased significantly in the negative control group compared to the test groups. Immunohistochemical and western blot analyses showed a corresponding elevation in the expression of apoptotic biomarker-caspase 3 and nuclear erythroid 2-related factor 2 (Nrf2) protein in STZ-diabetes group relative to the test groups. SeNPs and/or LMLNPs significantly ameliorated the various alterations imposed by STZ-diabetes relative to the control group. The chemotherapeutic influence in STZ-diabetic rats could be elicited via augmentation of antioxidant defence systems, regulation of Nfr2 expression, decrease in lipid peroxidation and regulation of apoptosis in the studied tissues.

Syringic acid protects from isoproterenol induced cardiotoxicity in rats

Identification of pharmacologically potent antioxidant compounds for their use in preventive medicine is thrust area of current research. This study was undertaken with the aim of determining the protective role of syringic acid (SA) on isoproterenol (ISO) induced myocardial infarction (MI) in rats. SA was orally given to rats for 21 days at three different concentrations (12.5, 25 and 50 mg/kg). At 20th and 21st day, rats were subcutaneously injected with ISO and at the end of experimental period, rats were killed. ISO induced myocardial damage was averted by pre-co-treatment of SA, as decrease was found in serum level of marker enzymes (CKMB, LDH, AST, ALT), lipid peroxidation, protein carbonyl (PC) and proinflammatory cytokines (TNFα, IL 6). Furthermore, content of glutathione (GSH) and activities of antioxidant enzymes in heart tissue were significantly raised. Improvement in infarct size and erythrocyte (RBCs) morphology was also observed. The biochemical findings were supported by histopathological outcome and protective effect of SA was found to be dose dependent. The results of our study demonstrated that the cardioprotective potential of SA in rat model of ISO induced MI might be due to anti-lipid peroxidative and endogenous antioxidant system enhancement effects.

Moringa oleifera stem extract protect skin keratinocytes against oxidative stress injury by enhancement of antioxidant defense systems and activation of PPARα

Oxidative stress is an important cause of skin injury induced by UVB radiation. Moringa oleifera also known as horseradish tree or drumstick tree, have multiple nutraceutical or pharmacological functions. However, whether Moringa oleifera protects skin against oxidative stress injury remains unknown. To investigate the effects of the ethanol extract of Moringa oleifera stem (MSE) on skin oxidative stress injury and its molecular mechanism, we first determined the effect of MSE on epidermal oxidative stress injury induced by H2O2 in keratinocytes (HaCaT cells) and by UVB-radiation in mice. Then we investigated the effect of MSE on the enhancement of antioxidant system and activation of PPARα in vitro and in vivo. Furthermore, the flavonoids compositions in MSE were assayed by high-performance liquid chromatography (HPLC), and then molecular docking study was used to assess the major component in MSE to activate PPARα. Our results indicate that MSE (100–400 μg/mL) protected the epidemic cell against oxidative stress injury in vitro and topical treatment with MSE cream (6%) inhibit UVB-induced oxidative stress injury in the epidermis of the mouse skin. PPARα activation is involved in the protective effect of MSE. HPLC assay and molecular docking study indicated that rutin might be the main component in MSE to activate PPARα. These results confirm that MSE exerts the protective effect on oxidative stress induced skin keratinocytes injury. Moreover, the protective effect of MSE is mediated by enhancement of antioxidant defense systems and activation of PPARα in skin keratinocytes.

GABA mediates phenolic compounds accumulation and the antioxidant system enhancement in germinated hulless barley under NaCl stress

In this study, the function of γ-aminobutyric acid (GABA) on the phenolic compounds accumulation and antioxidant system enhancement in germinated hulless barley under NaCl stress was investigated. Results showed that exogenous GABA induced the accumulation of phenolic compounds. It was observed that the activities and gene expression of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), 4-coumarate coenzyme A ligase (4CL), p-coumaric acid 3-hdroxylase (C3H), caffeic acid O-methyltransferase (COMT) and ferulic acid 5-hydroxylase (F5H) which are involved in phenolics biosynthesis was up-regulated by NaCl stress plus GABA treatment. In addition, antioxidant enzymes activities were induced. However, these effects were suppressed by 3-mercaplopropionic acid (3-MP), an inhibitor of GABA synthesis. This inhibition could be alleviated partly by exogenous GABA. These results suggested that GABA was essential for mediating NaCl stress-induced phenolic compounds accumulation and the antioxidant system enhancement in germinated hulless barley.

Hydrogen gas mediates ascorbic acid accumulation and antioxidant system enhancement in soybean sprouts under UV-A irradiation

The soybean sprout is a nutritious and delicious vegetable that is rich in ascorbic acid (AsA). Hydrogen gas (H2) may have potential applications in the vegetable processing industry. To investigate whether H2 is involved in the regulation of soybean sprouts AsA biosynthesis under UV irradiation, we set 4 different treatments: white light(W), W+HRW, UV-A and UV-A+HRW. The results showed that H2 significantly blocked the UV-A-induced accumulation of ROS, decreased TBARS content and enhanced SOD and APX activity in soybean sprouts. We also observed that the UV-A induced accumulation of AsA was enhanced more intensely when co-treated with HRW. Molecular analyses showed that UV-A+HRW significantly up-regulated AsA biosynthesis and recycling genes compared to UV-A in soybean sprouts. These data demonstrate that the H2 positively regulates soybean sprouts AsA accumulation under UV-A and that this effect is mediated via the up-regulation of AsA biosynthesis and recycling genes.

Enhancement of Antioxidant Systems and Storability of Two Plum Cultivars by Preharvest Treatments with Salicylates.

In this research the effect of salicylic acid (SA), acetylsalicylic acid (ASA), and methylsalicylate (MeSA) treatments, applied as a foliar spray during on-tree plum development, on fruit quality attributes, bioactive compounds, antioxidant activity, and the activity of the antioxidant enzymes at harvest and after long-term cold storage was evaluated in two plum cultivars (“Black Splendor”, BS, and “Royal Rosa”, RR). At harvest, plum quality parameters, such as weight, total phenolics (including anthocyanins, in BS), total carotenoids, and antioxidant activity, in both hydrophilic and lipophilic compounds were found at higher levels in plums from SA-, ASA-, and MeSA-treated trees than in those from control trees. During storage, fruit firmness, total acidity, and antioxidant compounds were at higher levels in treated, than in control, plums, which show an effect of salicylate treatments on delaying the plum postharvest ripening process. In addition, the activity of the antioxidant enzymes catalase (CAT), peroxidase (POX), superoxide dismutase (SOD), and ascorbate peroxidase (APX) were also enhanced at the time of harvest in salicylate-treated plums as compared with plums from control trees. The activity of these antioxidant enzymes was also found at higher levels in salicylate-treated plums during storage. Thus, preharvest treatment with salicylates could be a safe, eco-friendly, and new tool to improve and maintain plum quality attributes, and especially their content of antioxidant compounds, with an additional effect on delaying the postharvest ripening process through increasing the levels of antioxidant compounds and the activity of the antioxidant enzymes.

Effect of Ergotamine and its Combination with Vitamin E or Melatonin on Total Antioxidant Status in Migraine Patients

Free radicals and oxidative damage caused by them have being suggested to be involved in the pathogenesis of migraine. These may result from distorted equilibrium of pro-oxidant/anti-oxidant system that continuously generates and detoxifies oxidants during normal aerobic metabolism. Escape of such system from equilibrium leads to damage of cellular elements with the depletion of cellular stores of anti-oxidants material such as glutathione and vitamin E. Therefore, free radical scavengers (vitamin E or melatonin) seems to be of potential benefit as prophylactic anti-migraine therapy by neutralizing free radicals overproduction and possibly preventing formation of highly toxic intermediates (such as nitric oxide). In addition of being powerful antioxidant, melatonin was shown to possess promising effects in modulating severity, frequency and duration of migraine attacks. For this reason the present study was conducted to investigate the involvement of changed anti-oxidant defense (measured as total antioxidant status “TAS”) during migraine attack and the possible modulation of such status by classical anti-migraine therapy (ergotamine), antioxidants (vitamin E and melatonin) and their combination. 23 normal subjects and 21 migraine patients with age range of (17-45) years were enrolled in the study. Patients were diagnosed according to neurologist decision to have migraine with and without aura. Migraine patients were divided into three treatment groups; first group treated with ergotamine alone, second group with ergotamine /vitamin E and third group with ergotamine /melatonin. All groups were advised to take their treatments during attacks. Blood samples were drawn from migraine patients and normal subjects before initiation of therapy and after pain has been relived (from migraine patients only) for the investigation of TAS . The results of the study showed that TAS was significantly lower in migraine patients in comparison to control healthy subjects (P<0.05) with a percent reduction ranged from 35.46% to 43.97%. However, there is no significant difference in the level of TAS among migraine patients (P>0.05). Treatment with ergotamine raised significantly the level of TAS by 157%. The addition of vitamin E or melatonin greatly raised TAS by 179% and 176% respectively. The addition of vitamin E to ergotamine showed superior effect to that when melatonin was added. The greater reduction in TAS seen in this study among migraine patients in comparison to control healthy subjects suggests the presence of generalized decrease in antioxidant defense elements. Elevation of TAS by all treatments was very clear. In conclusion the decrease in TAS can be implicated in the pathophysiology of migraine and enhancement of antioxidant system can add a beneficial effect for the management of migraine headache with the use of antioxidants (vitamin E or melatonin) with classical anti-migraine drug.

When Bad Guys Become Good Ones: The Key Role of Reactive Oxygen Species and Nitric Oxide in the Plant Responses to Abiotic Stress.

The natural environment of plants is composed of a complex set of abiotic stresses and their ability to respond to these stresses is highly flexible and finely balanced through the interaction between signaling molecules. In this review, we highlight the integrated action between reactive oxygen species (ROS) and reactive nitrogen species (RNS), particularly nitric oxide (NO), involved in the acclimation to different abiotic stresses. Under stressful conditions, the biosynthesis transport and the metabolism of ROS and NO influence plant response mechanisms. The enzymes involved in ROS and NO synthesis and scavenging can be found in different cells compartments and their temporal and spatial locations are determinant for signaling mechanisms. Both ROS and NO are involved in long distances signaling (ROS wave and GSNO transport), promoting an acquired systemic acclimation to abiotic stresses. The mechanisms of abiotic stresses response triggered by ROS and NO involve some general steps, as the enhancement of antioxidant systems, but also stress-specific mechanisms, according to the stress type (drought, hypoxia, heavy metals, etc.), and demand the interaction with other signaling molecules, such as MAPK, plant hormones, and calcium. The transduction of ROS and NO bioactivity involves post-translational modifications of proteins, particularly S-glutathionylation for ROS, and S-nitrosylation for NO. These changes may alter the activity, stability, and interaction with other molecules or subcellular location of proteins, changing the entire cell dynamics and contributing to the maintenance of homeostasis. However, despite the recent advances about the roles of ROS and NO in signaling cascades, many challenges remain, and future studies focusing on the signaling of these molecules in planta are still necessary.

Nitric oxide mediates isoflavone accumulation and the antioxidant system enhancement in soybean sprouts

In this study, we investigated the relationships between endogenous NO signal transduction pathways, the antioxidant system and isoflavone accumulation induced by UV-B radiation in soybean sprouts. Results showed that UV-B-triggered NO generation induced isoflavone accumulation by up-regulating the activity and gene expression of key enzymes (phenylalanine ammonia lyase, PAL; chalcone isomerase, CHI; chalcone synthase, CHS; isoflavone synthase, IFS) that participate in isoflavone biosynthesis and enhanced the antioxidant system by regulating levels of antioxidants (glutathione reductase, GR; glutathione S-transferase, GST; ascorbate peroxidase, APX; glutathione GSH; ascorbic acid, ASC), antioxidant enzyme activities (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT) and their gene expression. These effects were inhibited by the addition of a specific NO-scavenger, carboxy-PTIO (cPTIO). The inhibition was reversed through application of the exogenous NO donor, SNP. Overall, NO is an essential signaling molecule, mediating UV-B-induced isoflavone accumulation and the antioxidant system enhancement in soybean sprouts.

Proteomic profile of Citrus grandis roots under long-term boron-deficiency revealed by iTRAQ

Eighty-six differentially abundant proteins were identified in Citrus grandis roots in response to boron-deficiency using the iTRAQ technique and possible mechanism underlying boron-deficiency tolerance of citrus plants was identified. Boron (B) is an essential element for plant growth and development and adequate B supply is an important determinant of good quality and high yield of crops. B-deficiency is a worldwide problem in agricultural production including citrus. However, little is known about the molecular mechanism of plant tolerance to B-deficiency. Using the iTRAQ technique, 86 differentially abundant proteins were identified from B-deficient Citrus grandis roots. The adaptive strategy of C. grandis roots under B-deficiency was summarized as follows: (1) enhancement of alternative splicing of mRNA and DNA methylation; (2) up-regulation of post-translation modification (PTM) and turnover of proteins; (3) reinforcement of cellular transport; (4) enhancement of antioxidant system and signal transduction. In general, these results increase our understanding of molecular mechanisms underlining the resistance of citrus plant under B-deficiency. Further studies should focus on how do roots perceive B deficiency in the rhizosphere and which pathway or proteins react to this adverse condition in the first place and then stimulates the downstream responses in Citrus plants.