Superoxide Dismutase Isozymes Research Articles

GA3 and BAP phytohormone seed priming enhances germination and PEG induced drought stress tolerance in soybean by triggering the expression of osmolytes, antioxidant enzymes and related genes at the early seedling growth stages

Drought stress strongly affects seed germination and seedling development during the early stages of plant growth in soybean (Glycine max L.). Seed priming with phytohormone (PH) is known to regulate various physiological and biochemical processes that govern plant growth and yield under optimal and stress conditions. In the present study, the effects of seed priming with Gibberellic acid (GA3) (0.28 mM), 6-Benzyl aminopurine (BAP) (20 mM) and Methyl Jasmonate (MJ) (2.5 mM) was studied during germination and at early seedling growth stages in JS-335 (drought sensitive) and MAUS-71 (moderately drought tolerant) soybean varieties under PFG induced drought stress conditions. The seed priming effects were studied in terms of germination percentage and rate (Timson Index), accumulation of osmolytes (proline and glycine betaine), antioxidant enzymes activity (superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT)), and the relative expression of genes viz., Cu/Zn-superoxide dismutase copper chaperone (SOD-CCS) , iron-superoxide dismutase (SODB2) , betaine aldehyde dehydrogenase (BADH2) and dehydration-responsive element binding protein (DREB2A). The germination percentage of non-primed soybean seeds decreased under drought stress but significantly increased upon GA3 and BAP priming. Interestingly, seed priming with MJ completely inhibited the germination in both the varieties. GA3 and BAP seed priming increased proline and glycine betaine accumulation under PEG induced drought stress in both the soybean varieties. The results showed that the activities of SOD, APX and CAT were significantly enhanced in the leaves of seedlings raised from GA3 and BAP-primed seeds, as compared to the non-primed seeds under the drought stress conditions. Isozyme profiling of SOD and APX revealed that the GA3 and BAP seed priming treatments enhanced the drought-inducible expression of SOD isozymes rather than inducing novel isoforms. In case of APX isozymes, GA3 seed priming appears to preserve APX isozyme diversity in both varieties, and BAP seed priming elevated the expression of APX isoforms in both soybean varieties under the drought conditions. In response to the drought stress, relative expression of the genes associated with superoxide dismutase and glycine betaine viz., SOD CCS, SODB2, BADH2 and DREB2A was markedly upregulated in the leaves of seedlings raised from the GA3 and BAP primed seeds in both the soybean varieties. The global correlation analysis designated that the osmolyte Proline, antioxidant enzyme APX and CAT, and SOD CCS, SODB2, BADH2 and DREB2A genes were potent regulator for drought stress tolerance mechanism in soybean. This study illuminates the intricate interplay of GA3 and BAP hormonal seed priming during the germination and early seedling stages in soybean plants under the drought stress. This finding emphasizes the critical consideration of genotype specific reactions to the hormonal seed priming under PEG induced drought stress conditions.

Identification and characterization of the critical genes encoding Cd-induced enhancement of SOD isozymes activities in Zhe-Maidong (Ophiopogon japonicus).

Superoxide dismutase (SOD) protects plants from abiotic stress-induced reactive oxygen species (ROS) damage. Here, the effects of cadmium (Cd) exposure on ROS accumulation and SOD isozymes, as well as the identification of significant SOD isozyme genes, were investigated under different Cd stress treatments to Zhe-Maidong (Ophiopogon japonicus). The exposure to Cd stress resulted in a notable elevation in the SOD activity in roots. Cu/ZnSODa and Cu/ZnSODb were the most critical SOD isozymes in response to Cd stress, as indicated by the detection results for SOD isozymes. A total of 22 OjSOD genes were identified and classified into three subgroups, including 10 OjCu/ZnSODs, 6 OjMnSODs, and 6 OjFeSODs, based on the analysis of conserved motif and phylogenetic tree. Cu/ZnSOD-15, Cu/ZnSOD-18, Cu/ZnSOD-20, and Cu/ZnSOD-22 were the main genes that control the increase in SOD activity under Cd stress, as revealed via quantitative PCR and transcriptome analysis. Additionally, under various heavy metal stress (Cu2+, Fe2+, Zn2+, Mn2+), Cu/ZnSOD-15, Cu/ZnSOD-18, and Cu/ZnSOD-22 gene expression were significantly upregulated, indicating that these three genes play a critical part in resisting heavy metal stress. The molecular docking experiments performed on the interaction between oxygen ion (O2•-) and OjSOD protein have revealed that the critical amino acid residues involved in the binding of Cu/ZnSOD-22 to the substrate were Pro135, Ile136, Ile140, and Arg144. Our findings provide a solid foundation for additional functional investigations on the OjSOD genes, as well as suggestions for improving genetic breeding and agricultural management strategies to increase Cd resistance in O. japonicus.

Identification of Superoxide Dismutase (SOD) Isozymes in Plant Tissues.

Superoxide and hydrogen peroxide are reactive oxygen species (ROS) involved in the oxidation of multiple biological molecules and the signaling processes during plant growth and stress response. Thus, control of ROS is fundamental for cell survival and development, with superoxide dismutase (EC 1.15.1.1, SOD) being one of the main enzymes involved. Different isoforms of SOD catalyze the dismutation of superoxide (O2.-) to hydrogen peroxide (H2O2) and oxygen (O2), such as Mn-SODs, Cu,Zn-SODs, and Fe-SODs. Using non-denaturing polyacrylamide gel electrophoresis (PAGE) combined with a specific staining method for SOD activity, the protocol describes the identification of different SOD isozymes, based on their differential inhibition by KCN and H2O2, in different organs and plant species such as pea (Pisum sativum L.) leaves and pepper (Capsicum annuum L.) fruits.

Foliar spray of Si and Ti nanoparticles affected enzymatic antioxidants in rapeseed (Brassica napus L.)

Some beneficial nanoparticles such as silicon and titanium are encouraging in foliar feeding due to their large surface area and biocompatible properties. In current experiment, seedling of rapeseed varieties (‘Hydromel’, ‘Nathalie’, ‘Alonso’) was sprayed with titanium dioxide and silicon dioxide nanoparticles (Ti and Si-NPs) and then responses of some enzymatic antioxidant and plasma membrane integrity were evaluated. Foliar application of Si-NPs significantly increased the activity of ascorbate peroxidase compared to the control, in all three varieties. Spray of both Ti and Si-NPs increased guaiacol peroxidase activity in ‘Nathalie’ and ‘Alonso’ varieties while in ‘Hydromel’ only Si-NPs spray had positive effects on activity this antioxidant. Behaviors of superoxide dismutase (SOD) isozymes under different foliar treatments and in varieties were different, but the highest activity of total SOD isozyme in ‘Hydromel’ and ‘Alonso’ varieties was obtained by foliar application of Si-NPs and Ti-NPs, respectively. The lowest amount of hydrogen peroxide was obtained by foliar application of Ti-NPs. Examination of malondialdehyde (MDA) also showed that the most vulnerable membrane belonged to ‘Hydromel’ variety and foliar application of Si-NPs and Ti-NPs could improve membrane integrity. These results suggest that foliar application of both Si-NPs and Ti-NPs improves the scavenging capacity of reactive oxygen species (ROS), although the response of the enzymatic antioxidants was largely influenced by the variety.

High Salinity Stimulates the Adaptive Response to Potassium Deficiency Through the Antioxidant and the NADPH-Generating Systems in the Roots and Leaves of the Halophyte Cakile maritima

Salinity is one of the most constraining environmental factors that limits plant growth and productivity because it disturbs mineral nutrition by triggering interactions at the interface soil roots. It implies a notable competition between sodium (Na+) and potassium (K+), with this last mineral being a key nutrient for plants. Using the halophyte Cakile maritima as a model plant grown in hydroponic conditions, this study was aimed to analyze how the simultaneous stressful conditions of high salinity (400 mM NaCl) and K+ deficiency (0 mM) for 15 days affect plant growth, ion balance, and antioxidant and NADPH-generating systems. Among the parameters analyzed, the most remarkable changes were observed in leaves, with drastic increases in the Na+/K+, Na+/Ca2+ and Na+/Mg2+ ratios, an enhanced accumulation of anthocyanins, and the induction of 3 new copper/zinc superoxide dismutase (CuZnSOD) isozymes in plants simultaneously exposed to both stresses. Taken together, the data revealed that the combination of both, high salinity and K+ deficiency, caused oxidative stress and modulated the whole antioxidative response of C. maritima in leaves and roots. Besides the differential response underwent by both organs, considering the different parameters analyzed under these stressful conditions, the most notable traits were that the effect of both stresses seems to be not additive and that salinity appears to improve C. maritima response to K+, a behavior not manifested in glycophyte species. Taken together our data support that, under extreme conditions that lead to an excess of ROS production, the induction of several CuZn-SODs in C. maritima may be one of the most outstanding strategies for the adaptation of this plant species to survive.

Superoxide dismutase isozymes in cerebral organoids from autism spectrum disorder patients.

Autism spectrum disorder is a pervasive neurodevelopmental disorder with a substantial contribution to the global disease burden. Despite intensive research efforts, the aetiopathogenesis remains unclear. The Janus-faced antioxidant enzymes superoxide dismutase 1-3 have been implicated in initiating oxidative stress and as such may constitute a potential therapeutic target. However, no measurement has been taken in human autistic brain samples. The aim of this study is to measure superoxide dismutase 1-3 in autistic cerebral organoids as an in vitro model of human foetal neurodevelopment. Whole brain organoids were created from induced pluripotent stem cells from healthy individuals (n = 5) and individuals suffering from autism (n = 4). Using Pierce bicinchoninic acid and enzyme-linked immunosorbent assays, the protein and superoxide dismutase 1, 2, and 3 concentrations were quantified in the cerebral organoids at days 22, 32, and 42. Measurements were normalized to the protein concentration. Results represented using medians and interquartile ranges. Using Wilcoxon matched-pairs signed-rank test, an abrupt rise in the superoxide dismutase concentration was observed at day 32 and onwards. Using Wilcoxon rank-sum test, no differences were observed between healthy (SOD1: 35.56ng/mL ± 3.46; SOD2: 2435.80ng/mL ± 1327.00; SOD3: 1854.88ng/mL ± 867.94) and autistic (SOD1: 32.85ng/mL ± 5.26; SOD2: 2717.80ng/mL ± 1889.10; SOD3: 1690.18ng/mL ± 615.49) organoids. Cerebral organoids recapitulate many aspects of human neurodevelopment, but the diffusion restriction may render efforts in modelling differences in oxidative stress futile due to the intrinsic hypoxia and central necrosis.

Old dogs, new tricks: New insights into the iron/manganese superoxide dismutase family

Superoxide dismutases (SODs) are ancient enzymes of widespread importance present in all domains of life. Many insights have been gained into these important enzymes over the 50 years since their initial description, but recent studies in the context of microbial pathogenesis have resulted in findings that challenge long established dogmas. The repertoire of SODs that bacterial pathogens encode is diverse both in number and in metal dependencies, including copper, copper and zinc, manganese, iron, and cambialistic enzymes. Other bacteria also possess nickel dependent SODs. Compartmentalization of SODs only partially explains their diversity. The need for pathogens to maintain SOD activity across distinct hostile environments encountered during infection, including those limited for essential metals, is also a driver of repertoire diversity. SOD research using pathogenic microbes has also revealed the apparent biochemical ease with which metal specificity can change within the most common family of SODs. Collectively, these studies are revealing the dynamic nature of SOD evolution, both that of individual SOD enzymes that can change their metal specificity to adapt to fluctuating cellular metal availability, and of a cell's repertoire of SOD isozymes that can be differentially expressed to adapt to fluctuating environmental metal availability in a niche.

Effect of soil drenching with humic acid, L-methionine and phosphoric acid on Fusarium wilt and induction of enzymes related to oxidative stress and defense in tomato plants

The main objective of the present study was to evaluate the efficacy of humic acid, L-methionine and phosphoric acid as a soil application for controlling Fusarium wilt disease of tomato and their effect on gene expression alterations using protein and isozyme profiling. Two isolates from each of Fusarium oxysporum f. sp. lycopersici (FOL) and F. solani (FS) were obtained from diseased tomato plants. According to pathogenicity tests, all tested isolates were able to infect tomato cultivars; cv. Super Jackal and cv. 745 under greenhouse conditions. In in vitro studies, the addition of humic acid, L-methionine and phosphoric acid to the medium at different concentrations reduced the growth of the tested isolates of the pathogens. Under greenhouse conditions, the addition of humic acid at 2%, 2 g/L of L-methionine and 0.6% of phosphoric acid to infested soil after sowing significantly decreased percentage disease severity of Fusarium wilt at both seasons (2016/17 and 2017/18). Protein bands at molecular weight 47.2 KD, 38.2 KD, 16.3 KD and 15.6 KD appeared only in treated plants. New esterase, peroxidase, chitinase and superoxide dismutase isozyme bands were detected in all treatments while not appear in the control. This results revealed that these treatments were able to induced new protein which increases resistance in tomato plants to Fusarium wilt disease.

EVALUATION OF BREAD WHEAT ADVANCED LINES UNDER SALINITY CONDITIONS USING TOLERANCE INDICES

This work focused on investigating the performance of thirteen newly wheat breeding lines compared with two check varieties under two salinity conditions; 6000 and 9000 ppm. The objectives were to determine salt-tolerant and sensitive genotypes using diverse tolerance indices. Additionally, to assess the genetic variability, heritability, genetic gain and genetic diversity among breeding lines using ISSR markers, protein electrophoresis and superoxide dismutase isozymes (SOD). The phenotypic and genotypic coefficients of variation displayed maximum values for number of spikes/m2, grain yield and number of grains/spike. Seven tolerance indices were calculated; SSI, TOL, MP, GMP, STI, YI and YSI for all evaluated genotypes. The highest scores of all indices were registered by G10 followed by G3, G13, G7 and G1; on the contrary, the lowest values were recorded by G12, G8 and G5. Cluster analysis was performed based on tolerance indices and the genotypes were divided into four groups ranged from highly salt-tolerant to highly sensitive genotypes. ISSR-PCR analysis displayed 105 DNA fragments using 6 selected primers detected 77 polymorphic bands and 28 monomorphic bands. Protein electrophoresis revealed that the number of bands for all genotypes ranged from 11 to 14 with molecular weights ranged between 6 to 130 kDa under salinity stress conditions. Unique bands of molecular weights 17 and 20 kDa were detected just for G3 and G4. SOD patterns indicated more intensive bands for G3 and G4 under salinity stress.

Superoxide dismutase (SOD) as a selection criterion for triticale grain yield under drought stress: a comprehensive study on genomics and expression profiling, bioinformatics, heritability, and phenotypic variability

BackgroundThe main objectives of this study were to find the possible structural association between the activity of enzymatic antioxidants and the grain yield of triticale plants as well as identifying the genotypic variability which might be effective on this association. Accordingly, expression levels of superoxide dismutase (SOD) isozymes (Mn-SOD, Cu/Zn-SOD, and Fe-SOD) were appraised to distinguish any possible relationship between SOD expression and drought resistance of triticale. A novel analytical method for distinguishing elite genotypes based on measured features was proposed. Additionally, a new programing based on SAS-language (IML) was introduced to estimate the genetic parameters rooted from combined ANOVA model (linear mixed model), which is capable of being used in any field study other than the current one.MethodsThirty genotypes of triticale were studied under normal and drought stress conditions during 6 years (three different locations). Accordingly, based on the results of genetic variability, heatmap analysis, biplot graph, and clustering technique, two genotypes with the highest genetic distance were selected to appraise the differential expression profiling of three SOD isozyme in shoot and root organs.ResultsField experiments and bioinformatics results showed that superoxide dismutase (SOD) was the most influential antioxidant in resistance of triticale to drought stress; therefore, it could be used as an indirect selection index in early stages to distinguish resistant genotypes to drought stress. Additionally, Mn-SOD and Fe-SOD showed roughly similar expression levels for both genotypes under drought stress. However, Cu/Zn-SOD expression level was higher in root and shoot of the tolerant genotype than the susceptible genotype.ConclusionHeatmap analysis that is applied for the first time to screen suitable genotypes, showed to be highly capable of distinguishing elite genotypes and pointing out the proper features for selection criteria. Bioinformatics results indicated that SOD is more important than other enzymatic antioxidant for being considered as selection criteria or candidate gene for transgenic purposes. Based on expressional results, Mn-SOD announced as a general isozyme that is probably highly expressed in most of the species, while, Cu/Zn-SOD was introduced as a genotype specific isozyme that is likely more expressed in tolerant genotypes

Alleviation Effects of Diosmetin on H2O2-Induced Oxidative Damage in Human Erythrocytes

Free radicals (FRs) are formed in the high amounts result of the metabolic imbalance in cells and tissue. These radicals-induced oxidative damages constitute the basis of many diseases. Organisms have antioxidant defence systems (ADS) to eliminate the destructive effects of the oxidative damage. In addition to these antioxidant systems, dietary flavonoids have the antioxidant effect and the protective role against oxidative damage. In the present study, it was investigated whether a flavonoid derived diosmetin (10, 50, and 100 µM) have the elimination potential on hydrogen peroxide (H2O2)-induced oxidative damage in erythrocyte culture by using biomarkers such as lipid peroxidation (LP) level, catalase (CAT), total superoxide dismutase (SOD) activity and changes of SOD isozymes containing the manganese SOD (Mn SOD) and the cupper-zinc SOD (CuZn SOD). CAT, total SOD, Mn SOD and CuZn SOD activities showed a serious decline with H2O2 treatment, but diosmetin addition significantly increased their activities. While the H2O2 application critically increased LP products in erythrocytes, diosmetin considerably reduced these oxidative damage products. In conclusion, it has been determined that diosmetin can moderate oxidative damage in human erythrocytes by activating or protecting the ADS.

Concentration/activity of superoxide dismutase isozymes and the pro-/antioxidative status, in context of type 2 diabetes and selected single nucleotide polymorphisms (genes: INS, SOD1, SOD2, SOD3) – Preliminary findings

The alterations in concentration/activity of superoxide dismutase isozymes in the context of type 2 diabetes or obesity are well-described. Moreover, many hereditary factors, including single-nucleotide polymorphisms (SNPs) of genes for coding insulin, insulin receptors, or insulin receptor substrates (INS, INSR, IRS1, IRS2) or superoxide dismutase isozymes (SOD1, SOD2, SOD3), have been linked with the incidence of obesity and diabetes. However, the underlying changes in the plasma concentration/activity of superoxide dismutase isozymes and their potential connection with the said hereditary factors remain unexplored. Previously, we have observed that the plasma concentration/activity of superoxide dismutase isozymes differs in the context of obesity and/or rs2234694 (SOD1) and rs4880 (SOD2) and that the concentrations of SOD1, SOD2, SOD3 are correlated with each other. Intersexual variability of SOD1 concentration was detected regardless of obesity. In this study, the variability of concentration/activity of superoxide dismutase isozymes in plasma is considered in the context of type 2 diabetes and/or SNPs: rs2234694 (SOD1), rs5746105 (SOD2), rs4880 (SOD2), rs927450 (SOD2), rs8192287 (SOD3). Genotypic variability of SNP rs3842729 (INS), previously studied in the context of insulin-dependent diabetes, is investigated in terms of selected clinical parameters associated with type 2 diabetes. This study revealed higher SOD1 concentration in diabetic men compared to women, and extremely high SOD1 concentration, higher total superoxide dismutase, and copper-zinc superoxide dismutase activity, and lower superoxide dismutase and copper-zinc superoxide dismutase activity (when adjusted for the concentration of SODs) in the diabetic group regardless of sex. Multiple logistic regression, applied to explore possible links between the studied SNPs and other factors with the odds of type 2 diabetes or obesity, revealed that the genotypic variability of rs4880 (SOD2) could affect these odds, supporting the findings of several other studies.

Impact of Foliar Application of Chitosan Dissolved in Different Organic Acids on Isozymes, Protein Patterns and Physio-Biochemical Characteristics of Tomato Grown under Salinity Stress.

In this study, the anti-stress capabilities of the foliar application of chitosan, dissolved in four different organic acids (acetic acid, ascorbic acid, citric acid and malic acid) have been investigated on tomato (Solanum lycopersicum L.) plants under salinity stress (100 mM NaCl). Morphological traits, photosynthetic pigments, osmolytes, secondary metabolites, oxidative stress, minerals, antioxidant enzymes activity, isozymes and protein patterns were tested for potential tolerance of tomato plants growing under salinity stress. Salinity stress was caused a reduction in growth parameters, photosynthetic pigments, soluble sugars, soluble proteins and potassium (K+) content. However, the contents of proline, ascorbic acid, total phenol, malondialdehyde (MDA), hydrogen peroxide (H2O2), sodium (Na+) and antioxidant enzyme activity were increased in tomato plants grown under saline conditions. Chitosan treatments in any of the non-stressed plants showed improvements in morphological traits, photosynthetic pigments, osmolytes, total phenol and antioxidant enzymes activity. Besides, the harmful impacts of salinity on tomato plants have also been reduced by lowering MDA, H2O2 and Na+ levels. Chitosan treatments in either non-stressed or stressed plants showed different responses in number and density of peroxidase (POD), polyphenol oxidase (PPO) and superoxide dismutase (SOD) isozymes. NaCl stress led to the diminishing of protein bands with different molecular weights, while they were produced again in response to chitosan foliar application. These responses were varied according to the type of solvent acid. It could be suggested that foliar application of chitosan, especially that dissolved in ascorbic or citric acid, could be commercially used for the stimulation of tomato plants grown under salinity stress.

ACTIVITY AND CONTENT OF SUPEROXIDEDISMUTASE IZOZYMES IN GRANULOSE CELLS FROM COW OVARY FOLLICLES

The activity and content of superoxide dismutase isoforms (SOD) in granulosa cells from cow ovarian follicles were studied for research after slaughter of cows ovaries were selected, which according to the physiological state were divided into groups: with "fresh" ovulation, at the site of the ovulated follicle there is a hole, no corpus luteum or diameter up to 5 mm, red color (n = 14); with "early corpus luteum", diameter 10-20 mm, color red or brown (n = 41); with “late corpus luteum", diameter 5–15 mm, color yellow (n = 32); "follicular growth", without the corpus luteum (n = 84). The ovaries of cows with small (<4 mm), medium (4 - 7 mm) and large (> 7 mm) follicles were used. Antral fluid was obtained from the follicles, from which granulosa cells were isolated. Cells were suspended according to the volume of follicular fluid in the medium Dulbeccos modified Eagle medium (DME) with the addition of estrus serum of cows, follicular fluid, insulin and heparin. In cell culture, protein concentration, activity, and superoxide dismutase isozymes were determined. It was found that granulosa cells are characterized by SOD activity - 12.4 ± 0.74 IU / mg protein (6.8 ± 1.72 - 19.8 ± 3.75 IU / mg protein). The activity of SOD in the culture of granulosa cells had 5–6 isoforms of the enzyme. It was found that isoforms at the site of localization are divided into cytosolic, mitochondrial and extracellular proteins of SOD. The cytosolic isoform were represented by 3 - 4, and mitochondrial and extracellular have one active protein of the enzyme. he activity of the enzyme and the content of isoforms depended on the size of the follicles from which the cells are removed and the physiological state of the ovaries. The studied indicators characterize the intensity of oxidative metabolism as a whole in cells and in their individual parts and organelles. For cultivation, it is advisable to select granulosa cells from ovarian follicles of "follicular growth" and "late corpus luteum" because they are characterized by consistently high activity of SOD, which protects intracellular components from the cytotoxic action of superoxide anion.

Alterations in Concentration/Activity of Superoxide Dismutases in Context of Obesity and Selected Single Nucleotide Polymorphisms in Genes: SOD1, SOD2, SOD3.

Little is known about the contribution of each of the three superoxide dismutase isozymes (SODs) to the total SOD activity in extracellular fluids. This study was aimed to investigate the alterations in concentration/activity of (SODs) in plasma, in context of sex, obesity, exposition to cigarette smoke, and genotypic variability of five selected single nucleotide polymorphisms (SNPs) in genes SOD1, SOD2, SOD3. Men showed higher SOD1 concentration, lower SOD3 concentration and higher total antioxidative capacity (TAC) values. Intersexual variability was observed in concentration of copper, zinc, and cadmium. The obese showed higher total oxidative capacity regardless of sex. An increase in SOD2 activity was coexistent with obesity in men, and exposition to cigarette smoke in non-obese individuals. Additionally, in state of this exposition, Cu,Zn-SOD contribution to the total SOD was lower. Interestingly, over 90% of the obese were of C/T genotype of rs4880 (SOD2). Non-obese of T/T genotype (rs4880) were of lower total SOD activity due to decrease in both Cu,Zn-SOD and Mn-SOD activities. SNP rs2234694 was associated with differences in concentration of SODs, depending on obesity status. Correlations indicate that both TAC and SODs, together, may adapt to insulin resistance and inflammation-derived oxidative stress found in obesity. This topic should be further investigated.

Reactive Oxygen Species (ROS) Metabolism and Nitric Oxide (NO) Content in Roots and Shoots of Rice (Oryza sativa L.) Plants under Arsenic-Induced Stress

Arsenic (As) is a highly toxic metalloid for all forms of life including plants. Rice is the main food source for different countries worldwide, although it can take up high amounts of As in comparison with other crops, showing toxic profiles such as decreases in plant growth and yield. The induction of oxidative stress is the main process underlying arsenic toxicity in plants, including rice, due to an alteration of the reactive oxygen species (ROS) metabolism. The aim of this work was to gain better knowledge on how the ROS metabolism and its interaction with nitric oxide (NO) operate under As stress conditions in rice plants. Thus, physiological and ROS-related biochemical parameters in roots and shoots from rice (Oryza sativa L.) were studied under 50 μM arsenate (AsV) stress, and the involvement of the main antioxidative systems and NO in the response of plants to those conditions was investigated. A decrease of 51% in root length and 27% in plant biomass was observed with 50 μM AsV treatment, as compared to control plants. The results of the activity of superoxide dismutase (SOD) isozymes, catalase, peroxidase (POD: total and isoenzymatic), and the enzymes of the ascorbate–glutathione cycle, besides the ascorbate and glutathione contents, showed that As accumulation provoked an overall significant increase of most of them, but with different profiles depending on the plant organ, either root or shoot. Among the seven identified POD isozymes, the induction of the POD-3 in shoots under As stress could help to maintain the hydrogen peroxide (H2O2) redox homeostasis and compensate the loss of the ascorbate peroxidase (APX) activity in both roots and shoots. Lipid peroxidation was slightly increased in roots and shoots from As-treated plants. The H2O2 and NO contents were enhanced in roots and shoots against arsenic stress. In spite of the increase of most antioxidative systems, a mild oxidative stress situation appears to be consolidated overall, since the growth parameters and those from the oxidative damage could not be totally counteracted. In these conditions, the higher levels of H2O2 and NO suggest that signaling events are simultaneously occurring in the whole plant.

Antifungal potential of extracts produced from decomposed agricultural wastes by Bosea thiooxidans

This work aimed to produce antifungal bioactive compounds from agro-wastes using cellulolytic bacteria, and to evaluate their in vitro and in vivo antifungal activities against faba bean damping off disease caused by Rhizoctonia solani. To achieve this purpose, a total of 34 rhizospheric bacterial isolates were screened for their abilities to degrade cellulosic compounds. The bacterial isolate which gave the best cellulolytic activity was identified as Bosea thiooxidans, according to its morphological, biochemical characteristics, and according to its 16S rRNA sequencing. Five native plants remains including; Pomegranate peel, chili waste, prickly peel, olive leaves and garlic stalks, were hydrolyzed by the selected cellulolytic B. thiooxidans strain UAB7, and their extracts were tested for in vitro antifungal potential against a number of fungal phytopathogens mainly; Rizoctonia solani, Fusarium moniliform; Pythium sp. and Phytophothora sp. Extracts of the decomposed garlic and olive wastes gave inhibition percentages ranging from 25-100%, against the tested fungal pathogens. Transmission electron microscopy (TEM) showed cyto-morphological alterations and empty cavities in hyphae of the treated R. solani. Moreover, qualitative and quantitative analyses of the phenolic compounds present in the tested extracts were carried out. Results showed that among the tested phenolic compounds, kaempferol and phenanthrene were more abundant in the decomposed garlic and olive extracts, respectively. The fermented garlic and olive extracts were evaluated for their in vivo potency to suppress the damping off disease of faba bean caused by R. solani. Faba bean plants treated with the fermented garlic and olive extracts demonstrated significantly better disease suppression, compared to the infested control. Furthermore, bands recovered through the electrophoretic patterns of the superoxide dismutase and peroxidase isozymes in the infested control plants, showed wide differentiation in their intensities and forms, compared to the healthy and the treated plants.

Superoxide Radical Metabolism in Sweet Pepper (Capsicum annuum L.) Fruits Is Regulated by Ripening and by a NO-Enriched Environment.

Superoxide radical (O2•–) is involved in numerous physiological and stress processes in higher plants. Fruit ripening encompasses degradative and biosynthetic pathways including reactive oxygen and nitrogen species. With the use of sweet pepper (Capsicum annuum L.) fruits at different ripening stages and under a nitric oxide (NO)-enriched environment, the metabolism of O2•– was evaluated at biochemical and molecular levels considering the O2•– generation by a NADPH oxidase system and its dismutation by superoxide dismutase (SOD). At the biochemical level, seven O2•–-generating NADPH-dependent oxidase isozymes [also called respiratory burst oxidase homologs (RBOHs) I–VII], with different electrophoretic mobility and abundance, were detected considering all ripening stages from green to red fruits and NO environment. Globally, this system was gradually increased from green to red stage with a maximum of approximately 2.4-fold increase in red fruit compared with green fruit. Significantly, breaking-point (BP) fruits with and without NO treatment both showed intermediate values between those observed in green and red peppers, although the value in NO-treated fruits was lower than in BP untreated fruits. The O2•–-generating NADPH oxidase isozymes I and VI were the most affected. On the other hand, four SOD isozymes were identified by non-denaturing electrophoresis: one Mn-SOD, one Fe-SOD, and two CuZn-SODs. However, none of these SOD isozymes showed any significant change during the ripening from green to red fruits or under NO treatment. In contrast, at the molecular level, both RNA-sequencing and real-time quantitative PCR analyses revealed different patterns with downregulation of four genes RBOH A, C, D, and E during pepper fruit ripening. On the contrary, it was found out the upregulation of a Mn-SOD gene in the ripening transition from immature green to red ripe stages, whereas a Fe-SOD gene was downregulated. In summary, the data reveal a contradictory behavior between activity and gene expression of the enzymes involved in the metabolism of O2•– during the ripening of pepper fruit. However, it could be concluded that the prevalence and regulation of the O2•– generation system (NADPH oxidase-like) seem to be essential for an appropriate control of the pepper fruit ripening, which, additionally, is modulated in the presence of a NO-enriched environment.

Mycoremediation affects antioxidative status in winter rye plants grown at Chernobyl exclusion zone site in Ukraine.

Soil contaminated with heavy metals in general and radionuclides in particular represents an escalating problem for all living organisms. Since, Chernobyl nuclear power plant accident in 1986 in Ukraine, an exclusion zone of 30 km around the former power plant is uninhabitable land due to severe contamination. Two most notable beta emitters contributing to dose hazards for decades is radioactive 137Cs/90Sr. However, large parts of the zone are also highly contaminated with uranium particles (hot particles) bearing trace amounts of highly alpha-emitting radionuclides. We established an experiment at exclusion zone with the aim to investigate the influence of two macro fungi (Schizophyllum commune (S.C.) and Leucoagaricus naucinus (L.N.)) on oxidative status and antioxidative responses in winter rye plants; from this, we wanted to test the radionuclide/heavy metals retention capacity of both fungi, and probe their further potential for mycoremediation.Result shows some differences in the concentrations of radionuclides/heavy metals and micro/macronutrients uptake in plants. As a biomarker of oxidative status, lipid peroxidation (LPO) levels and other antioxidative parameters were determined, i.e., superoxide-dismutase (SOD) isoenzymes, cysteine (CYS), and ascorbic acid (AA) concentrations as well as catalase (CAT) and glutathione reductase (GR) activities in winter rye shoots. LPO showed no significant differences between controls and plants cultivated with macro fungi. However, CAT activities were elevated in the presence of S.C/L.N compared with control, while GR activity was significantly higher only in presence of S.C. In contrast, isozyme of SOD (Cu,Zn-SOD) was the most prominent in control. Likewise, CYS content was lower in plants grown with both fungi, while AA concentration was only lower in the presence of L.N. The results showed that presence of fungi in radionuclide contaminated soil caused induction of antioxidative response in shoots of winter rye and that the response depended on the type of fungi used.

Differential responses of antioxidants and dehydrin in two Switchgrass (Panicum virgatum L.) cultivars contrasting in drought tolerance

Abstract Drought stress is a major limiting factor for plant growth and development in many regions of the world. This study was designed to investigate antioxidant metabolism and dehydrin expression responses to drought stress in two switchgrass cultivars (drought tolerant Alamo, and drought sensitive Dacotah) contrasting in drought tolerance. The plants were subjected to well-watered [100% evapotranspiration (ET)] or drought stress (30%-50% ET) conditions for up to 24 d in growth chambers. Drought stress decreased leaf relative water content (RWC), increased leaf electrolyte leakage (EL), leaf malondialdehyde (MDA) content in two cultivars, but Alamo exhibited higher leaf RWC level, lower leaf EL and MDA when compared to Dacotah at 24 d of drought treatment. Drought stress also increased superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activities in two cultivars, Alamo had relatively higher SOD, CAT and APX activities and greater abundance of SOD and APX isozymes than Dacotah at 24 d of drought treatment. Alamo had higher abundance of 55 KDa and 18 KDa dehydrin accumulation than Dacotah under drought treatment. Relative genes expression level of PvCAT1, PvAPX2, PvERD and PvPIP1;5 in Alamo were significantly higher than Dacotah at 24 d of drought treatment. These results suggest that increase in antioxidant enzymes and accumulation of dehydrin were highly related with switchgrass drought tolerance. Antioxidant enzyme activity, isozyme expression and dehydrin abundance could provide a useful screening tool to identify relative drought tolerance in switchgrass cultivars.