Genes Encoding Antioxidant Enzymes Research Articles

Enriched endogenous free Spd and Spm in alfalfa (Medicago sativa L.) under drought stress enhance drought tolerance by inhibiting H2O2 production to increase antioxidant enzyme activity

Drought stress is a major factor limiting agricultural development, and exogenous polyamines (PAs) can increase plant drought resistance by enhancing antioxidant activity, but few studies have examined whether endogenous PAs enhance the plant antioxidant system. Here, to investigate the effects of endogenous PAs on the antioxidant system of alfalfa under drought stress and the underlying mechanisms, two alfalfa cultivars, Longzhong (drought resistant) and Gannong No. 3 (drought sensitive), were used as test materials, and their seedlings were treated with polyethylene glycol (PEG-6000) for 8 days at −1.2 MPa to simulate drought stress. The levels of free PAs [putrescine (Put), spermidine (Spd) and spermine (Spm)], hydrogen peroxide (H2O2), malondialdehyde (MDA), key PA metabolism enzyme [arginine decarboxylase (ADC), ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC), polyamine oxidase (PAO), and diamine oxidase (DAO)] activities, and antioxidant enzyme [superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)] activities were measured. These physiological indicators were used for correlation analysis to investigate the relationship between PA metabolism and the antioxidant enzyme system. The results showed that PA synthesis in alfalfa under drought stress was dominated by the ADC pathway. Spd and Spm played an important role in improving drought tolerance. The high levels of ADC and SAMDC activities were facilitated by the conversion of Put to Spd and Spm. H2O2 generation by oxidative decomposition of PAs was mainly dependent on the oxidative decomposition of DAO but not PAO. Low DAO activity favored low H2O2 production. Spd, Spm, ADC, ODC and SAMDC were positively correlated with the antioxidant enzymes SOD, CAT and POD in both cultivars under drought. Therefore, we concluded that high ADC and SAMDC activities in alfalfa promoted the conversion of Put to Spd and Spm, leading to high accumulation of Spd and Spm and low Put accumulation. Low Put levels led to low H2O2 production through low DAO activity, and low H2O2 levels induced the expression of antioxidant enzyme-encoding genes to improve antioxidant enzyme activity and reduce MDA accumulation and thereby enhanced drought resistance in alfalfa.

Strontium alleviated the growth inhibition and toxicity caused by cadmium in rice seedlings

Cadmium (Cd) contamination of rice is an urgent ecological and agricultural problem. Strontium (Sr) has been shown to promote plant growth. However, the effect of Sr on rice seedlings under Cd stress is currently unclear. In this work hydroponic experiments were used to assess the impact of Sr on rice seedling growth under Cd stress. The findings demonstrated that foliar application of 0.5 mg L−1 Sr had no discernible impact on the development of rice seedlings. However, Sr significantly alleviated growth inhibition and toxicity in rice seedlings when threatened by Cd. Compared with the Cd treatment (Cd, 2.5 mg L−1), the root length, shoot height, and whole plant length of rice seedlings in the Cd + Sr treatment (Cd, 2.5 mg L−1; Sr, 0.5 mg L−1) increased by 4.96 %, 12.47 % and 9.60 %, respectively. The content of Cd in rice decreased by 23.34 % (roots) and 5.79 % (shoots). Sr lessened the degree of membrane lipid peroxidation damage (lower MDA concentration) among the seedlings of rice under Cd stress by controlling the activities of antioxidant enzymes and GSH content. By changing the expression of antioxidant enzyme-encoding genes and downregulating the heavy metal transporter gene (OsNramp5), Sr reduced accumulation and the detrimental effects of Cd on rice seedlings. Our study provides a new solution to the problem of Cd contamination in rice, which may promote the safe production of rice and benefit human health.

MdNAC104 positively regulates apple cold tolerance via CBF-dependent and CBF-independent pathways.

Low temperature is the main environmental factor affecting the yield, quality and geographical distribution of crops, which significantly restricts development of the fruit industry. The NAC (NAM, ATAF1/2 and CUC2) transcription factor (TF) family is involved in regulating plant cold tolerance, but the mechanisms underlying these regulatory processes remain unclear. Here, the NAC TF MdNAC104 played a positive role in modulating apple cold tolerance. Under cold stress, MdNAC104-overexpressing transgenic plants exhibited less ion leakage and lower ROS (reactive oxygen species) accumulation, but higher contents of osmoregulatory substances and activities of antioxidant enzymes. Transcriptional regulation analysis showed that MdNAC104 directly bound to the MdCBF1 and MdCBF3 promoters to promote expression. In addition, based on combined transcriptomic and metabolomic analyses, as well as promoter binding and transcriptional regulation analyses, we found that MdNAC104 stimulated the accumulation of anthocyanin under cold conditions by upregulating the expression of anthocyanin synthesis-related genes, including MdCHS-b, MdCHI-a, MdF3H-a and MdANS-b, and increased the activities of the antioxidant enzymes by promoting the expression of the antioxidant enzyme-encoding genes MdFSD2 and MdPRXR1.1. In conclusion, this study revealed the MdNAC104 regulatory mechanism of cold tolerance in apple via CBF-dependent and CBF-independent pathways.

Heat, drought, and combined stress effect ontransgenic potato plants overexpressing theStERF94 transcription factor.

Despite their economic importance worldwide, potato plants are sensitive to various abiotic constraints, such as drought and high temperatures, which cause significant losses in yields and tuber quality. Moreover, because of the climate change phenomenon, plants are frequently subjected to combined stresses, mainly high temperatures and drought. In this context, breeding for tolerant varieties should consider not only plant response to drought or high temperature but also to combined stresses. In the current study, we studied transgenic potato plants overexpressing an ethylene response transcription factor (TF; StERF94) involved in abiotic stress response signaling pathways. Our previous results showed that these transgenic plants display tolerance to salt stress more than wildtype (WT). In this work, we aimed to investigate the effects of drought, heat, and combined stresses on transgenic potato plants overexpressing StERF94 TF under in vitro culture conditions. The obtained results revealed that StERF94 overexpression improved the tolerance of the transgenic plants to drought, heat, and combined stresses through better control of the leaf water and chlorophyll contents, activation of antioxidant enzymes, and an accumulation of proline, especially in the leaves. Indeed, the expression level of antioxidant enzyme-encoding genes (CuZnSOD, FeSOD, CAT1, and CAT2) was significantly induced by the different stress conditions in the transgenic potato plants compared with the WT plants. This study further confirms that StERF94 TF may be implicated in regulating the expression of target genes encoding antioxidant enzymes.

Arbuscular mycorrhizal symbiosis enhances perennial ryegrass growth during temperature stress through the modulation of antioxidant defense and hormone levels

Perennial ryegrass (Lolium perenne L.) refers to a vital species of grass grown extensively as a biofuel and biochemical production across temperate regions. However, both low temperature (LT) and high temperature (HT) conditions are unfavorable for the development of this species, causing reduced forage yield. Arbuscular mycorrhizal (AM) fungi are recognized for promoting host plants’ resistance to abiotic stresses via different mechanisms. However, the mechanism underlying the alleviation of plant damage induced by high-temperature stress and low-temperature stress by AM fungi remains to be elucidated so far. Therefore, the current work attempted to explore how the symbiosis with AM fungus Rhizophagus irregularis (R. irregularis) affects the antioxidant activity and hormone levels in ryegrass under LT and HT stresses and reveals the molecular mechanisms. In addition, the contents of non-enzymatic antioxidants, and hydrogen peroxide (H2O2), the activities of antioxidant enzymes, the genes encoding antioxidant enzymes, and the endogenous hormone-related genes in the perennial ryegrass inoculated with or without R. irregularis were analyzed upon exposure to LT and HT stresses. The results showed that inoculating AM plants with R. irregularis alleviated growth inhibition caused by LT and HT stress, as evidenced by significantly higher plant height, shoot and root dry weight, leaf chlorophyll and carotenoid content, net photosynthesis rate, and photochemical efficiency (Fv/Fm) in comparison to non- mycorrhizal (NM) plants under LT and HT stress. Under LT and HT conditions, AM symbiosis decreased electrolyte leakage (EL), malondialdehyde (MDA), H2O2, and abscisic acid (ABA) contents while significantly increasing the activities of our analyzed enzymes (with the exception of peroxidase (POD) in shoots and ascorbate peroxidase (APX) in roots), AsA/DHA and GSH/GSSG ratio, gibberellic acid 3 (GA3), jasmonic acid (JA) and indoleacetic acid (IAA) contents in shoots and roots. R. irregularis inoculation significantly upregulated almost all genes encoding antioxidant enzyme we tested (except for LpGPX1, LpGPX3, and LpGR in shoots, which were unaffected by AM symbiosis in 3d LT treatment) and some related genes in JA biosynthetic pathway, gibberellin synthesis as well as auxin transport and signaling while down-regulated the biosynthesis and signaling genes involved in ABA.In general, the findings suggested that AM symbiosis regulated the antioxidant defense and the hormone levels in ryegrass, which consequently alleviated the temperature stress-induced plant inhibition.

Association of Polymorphisms in Antioxidant Enzyme-Encoding Genes with Diabetic Nephropathy in a Group of Saudi Arabian Patients with Type II Diabetes Mellitus.

IntroductionAn imbalance between reactive oxygen species (ROS) generation and the defence mechanisms underlying the activity of antioxidant enzymes has been demonstrated as the leading pathology in diabetes mellitus (DM)-related microvascular complications.PurposeThis study aims to evaluate the association between polymorphisms in antioxidant enzyme-encoding genes: catalase (CAT); manganese superoxide dismutase (Mn-SOD); glutathione S transferase M1 (GSTM1); and GSTT1 glutathione S transferase T1 (GSTT1), and the risk of type II diabetic nephropathy (DN) in the Saudi population.Patients and MethodsThe present study involved 64 type II DM patients with nephropathy and 64 type II diabetes patients without nephropathy from the King Abdulaziz University (KAU) Hospital. They underwent real-time PCR genotyping for the Mn-SOD and CAT genes. Multiplex PCR was used to detect GSTM1- and GSTT1-null polymorphisms.ResultsA statistically significant difference was observed between the case and control groups with regard to polymorphisms in the CAT gene (P = 0.037), but not for polymorphisms in the Mn-SOD (P = 0.64) gene. In addition, a statistically significant association was observed between null polymorphisms of the GSTT1 and GSTM1 genes and DN in the case and control groups (P = 0.046 and P = 0.035, respectively).ConclusionOur results showed that the genetic ability to combat oxidative stress may play a major role in DN pathogenesis in Saudi type II DM patients. These polymorphisms in antioxidant enzyme-encoding genes could be used as independent genetic markers for the construction of risk prediction models for kidney-related complications in type II DM patients.

Ectopic expression of GmHP08 enhances resistance of transgenic Arabidopsis toward drought stress.

Ectopic expression of Glycine max two-component system member GmHP08 in Arabidopsis enhanced drought tolerance of transgenic plants, possibly via ABA-dependent pathways. Phosphorelay by two-component system (TCS) is a signal transduction mechanism which has been evolutionarily conserved in both prokaryotic and eukaryotic organisms. Previous studies have provided lines of evidence on the involvement of TCS genes in plant perception and responses to environmental stimuli. In this research, drought-associated functions of GmHP08, a TCS member from soybean (Glycine max L.), were investigated via its ectopic expression in Arabidopsis system. Results from the drought survival assay showed that GmHP08-transgenic plants exhibited higher survival rates compared with their wild-type (WT) counterparts, indicating better drought resistance of the former group. Analyses revealed that the transgenic plants outperformed the WT in various regards, i.e. capability of water retention, prevention of hydrogen peroxide accumulation and enhancement of antioxidant enzymatic activities under water-deficit conditions. Additionally, the expression of stress-marker genes, especially antioxidant enzyme-encoding genes, in the transgenic plants were found greater than that of the WT plants. In contrary, the expression of SAG13 gene, one of the senescence-associated genes, and of several abscisic acid (ABA)-related genes was repressed. Data from this study also revealed that the ectopic expression lines at germination and early seedling development stages were hypersensitive to exogenous ABA treatment. Taken together, our results demonstrated that GmHP08 could play an important role in mediating plant response to drought, possibly via an ABA-dependent manner.

Transgenic soybean overexpressing GmNAC085 enhanced expression of important genes under salinity stress condition

Climate change has made abiotic stresses such as drought and salinity bigger threats to ecosystem and global food security. In response to unfavorable conditions, physiological, biochemical and molecular activities in plants are altered. Particularly, various members of NAC (NAM, ATAF1/2, CUC2) transcriptional factor family have been reported to be the key regulators in modulating multiple biological processes of plant responses to osmotic stress conditions caused by drought and salinity. Previously, transgenic studies have shown the positive regulatory role of GmNAC085, a NAC transcription factor from soybean (Glycine max), in plant resistance against drought stress. Therefore, in this study, we extended the investigation on its contribution to salinity stress. According to our RT-qPCR analyses, expression of several important stress-related genes was significantly induced in the transgenic soybean plants in comparison with the wild-type plants, including antioxidant enzyme-encoding genes (GmSOD, GmAPX and GmCAT), sodium-proton antiporter encoding gene (GmNHX1) and proline metabolic gene (GmP5CS). Furthermore, biochemical results were also in agreement with the molecular data, with enhanced antioxidant enzyme activities of peroxidase and catalase, and in couple with lower cellular content of the reactive oxygen species hydrogen peroxide in the transgenic plants. Taken these altogether, the transgenic plants might acquire advantages in dealing with oxidative stress using enzymes and proline, as well as cellular Na+ removal under salinity stress conditions. Therefore, underlying mechanisms of GmNAC085 associated with salinity stress should be fully elaborated to find out its potential utility in crop improvement.

Wild Relatives of Wheat Respond Well to Water Deficit Stress: A Comparative Study of Antioxidant Enzyme Activities and Their Encoding Gene Expression

Previous studies have revealed that some wild wheat accessions respond well to water deficit treatments and have a good potential in terms of photosynthetic parameters, root system architecture, and several physiological properties. However, the biochemical responses and molecular mechanisms of antioxidant-encoding genes remain to be elucidated. Herein, we investigated the most tolerant accessions from A. crassa, Ae. tauschii, and Ae. cylindrica previously identified from a core collection in previous studies, along with a control variety of bread wheat (T. aestivum cv. Sirvan) through measuring the shoot fresh and dry biomasses; the activities of antioxidant enzymes (including ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GPX), and peroxidase (POD)); and the relative expression of CAT, superoxide dismutase (MnSOD), and GPX and APX genes under control and water deficit conditions. Water deficit stress caused a significant decrease in the shoot biomasses but resulted in an increase in the activity of all antioxidant enzymes and relative expression of antioxidant enzyme-encoding genes. Principal component analysis showed a strong association between the shoot dry biomass and the activity of CAT, POD, and APX, as well as MnSOD gene expression. Thus, these traits can be used as biomarkers to screen the tolerant plant material in the early growth stage. Taken together, our findings exposed the fact that Ae. tauschii and Ae. crassa respond better to water deficit stress than Ae. cylindrica and a control variety. Furthermore, these accessions can be subjected to further molecular investigation.

Overexpression of the NMig1 Gene Encoding a NudC Domain Protein Enhances Root Growth and Abiotic Stress Tolerance in Arabidopsis thaliana.

The family of NudC proteins has representatives in all eukaryotes and plays essential evolutionarily conserved roles in many aspects of organismal development and stress response, including nuclear migration, cell division, folding and stabilization of other proteins. This study investigates an undescribed Arabidopsis homolog of the Aspergillus nidulans NudC gene, named NMig1 (for Nuclear Migration 1), which shares high sequence similarity to other plant and mammalian NudC-like genes. Expression of NMig1 was highly upregulated in response to several abiotic stress factors, such as heat shock, drought and high salinity. Constitutive overexpression of NMig1 led to enhanced root growth and lateral root development under optimal and stress conditions. Exposure to abiotic stress resulted in relatively weaker inhibition of root length and branching in NMig1-overexpressing plants, compared to the wild-type Col-0. The expression level of antioxidant enzyme-encoding genes and other stress-associated genes was considerably induced in the transgenic plants. The increased expression of the major antioxidant enzymes and greater antioxidant potential correlated well with the lower levels of reactive oxygen species (ROS) and lower lipid peroxidation. In addition, the overexpression of NMig1 was associated with strong upregulation of genes encoding heat shock proteins and abiotic stress-associated genes. Therefore, our data demonstrate that the NudC homolog NMig1 could be considered as a potentially important target gene for further use, including breeding more resilient crops with improved root architecture under abiotic stress.

Arbuscular mycorrhizal symbiosis mitigates oxidative injury in black locust under salt stress through modulating antioxidant defence of the plant

Excess salt in the soil induces oxidative injury in plant cells. Arbuscular mycorrhizal (AM) fungi can impart host plants salt tolerance and mitigate the oxidative injury in the plants exposed to salt stress. In order to clarify the effects of AM symbiosis on antioxidant activities in Robinia pseudoacacia under salt stress conditions and explore the molecular mechanisms involved, the biomass production and oxidative injury, concentrations of H2O2 and non-enzymatic antioxidants (ascorbate and glutathione), activities of antioxidant enzymes as well as expression of five antioxidant enzyme-encoding genes (RpCu/Zn-SOD, RpMn-SOD, RpAPX1, RpAPX2 and RpGR) in R. pseudoacacia inoculated with or without AM fungi under salt stress were analysed. The results showed that salinity reduced the biomass production in both NM and AM plants, but the reduction was lower in AM plants than in NM plants. In leaves, the levels of REL, MDA and H2O2 were reduced by AM symbiosis. Meanwhile, the activities of almost all enzymes tested (except for POX, which was unaffected by AM symbiosis), the expression of five antioxidant enzyme-encoding genes and the concentrations of total, reduced and oxidized ascorbate and glutathione were increased by AM symbiosis. However, in roots, the H2O2 accumulation was upregulated by mycorrhizal colonization. Moreover, the activities of APX and MDHAR and concentrations of total, reduced and oxidized ascorbate were downregulated by AM symbiosis. In addition, the root MDA level was similar in NM and AM plants. The results of present study suggest that the mitigation of oxidative injury in R. pseudoacacia by AM symbiosis was more evident in leaves than in roots. The greater ability of AM plants to counteract oxidative stress resulted in the improved growth performance and salt tolerance of these plants under salt stress.

Ectopic co-expression of the SOD and APX genes enhanced callus growth and in vitro regeneration in Arabidopsis

Antioxidant enzymes, such as superoxide dismutase (SOD) and ascorbate peroxidase (APX), play important role in ROS homeostasis in plants. In the present study, two important antioxidant enzyme-encoding genes, cytosolic Cu/Zn-SOD and APX, were isolated from Potentilla atrosanguinea and Rheum australe plants, which grow at high-altitude regions of Himalaya. Previously, we have reported cytosolic overexpression of both the genes in Arabidopsis, individually and in combination and these transgenic plants exhibit cold and salt stress tolerance. In the present study, wild-type (WT) and transgenic lines (cytosolic Cu/Zn-SOD and APX) were analysed for their regeneration potential and expression profiling of various genes involved in in vitro regeneration was carried out. Among all transgenic lines, dual transgenics showed early callus induction and shoot regeneration. Callus growth rate and in vitro regeneration capacity were significantly higher in transgenic lines compared with control plants. Interestingly, H2O2 accumulation and SOD activity were found to be higher in SOD and dual transgenic lines during callus induction and shoot regeneration stages, indicating a correlation between H2O2 and SOD activity with regeneration process. Whereas APX activity in transgenic lines was found to be decreased in regenerated shoots, cotyledons, it was increased in callus and roots. Further, expression analysis of several genes involved in callus induction and in vitro regeneration using qRT-PCR showed that the majority of genes were significantly up-regulated (two- to fourfold) during different stages of regeneration in transgenic lines. Consequently, our results substantiate that a minimal amount of H2O2 accumulation brought about by overexpression of SOD and APX genes may play an important role in early callus induction and shoot regeneration in transgenic line. The overall results will add knowledge about the role of antioxidant genes in in vitro regeneration of plants.

Overexpression of AtWRKY30 Transcription Factor Enhances Heat and Drought Stress Tolerance in Wheat (Triticum aestivum L.).

Drought and heat factors have negative impacts on wheat yield and growth worldwide. Improving wheat tolerance to heat and drought stress is of the utmost importance to maintain crop yield. WRKY transcription factors help improve plant resistance to environmental factors. In this investigation, Arabidopsis WRKY30 (AtWRKY30) transcription factor was cloned and expressed in wheat. Plants growth, biomass, gas-exchange attributes, chlorophyll content, relative water content, prolines content, soluble proteins content, soluble sugars content, and antioxidant enzymes activities (catalase (CAT), superoxide dismutase (SOD), peroxidase (POX), and ascorbate peroxidase (APX)) of the AtWRKY30-overexpressing wheat plants were higher than those of the wild type. However, levels of electrolyte leakage, malondialdehyde, and hydrogen peroxide of the AtWRKY30-overexpressing wheat plants were significantly less than those of the wild-type. Additionally, the expression level of antioxidant enzyme-encoding genes and stress-responsive genes (ERF5a, DREB1, DREB3, WRKY19, TIP2, and AQP7) were significantly induced in the transgenic wheat plants in comparison with the wild type. In conclusion, the results demonstrated that AtWRKY30 overexpression promotes heat and drought tolerance in wheat by inducing gas-exchange attributes, antioxidant machinery, osmolytes biosynthesis, and stress-related gene expression. AtWRKY30 could serve as a potential candidate gene for improving stress tolerance in wheat.

Deterioration of Antioxidant Competence in Barley Lesion Mimic Mutant 194

A barley mutant, 194, was observed to exhibit leaf spot phenotype during the whole growing period. In the current research, the phenotype and antioxidant competence were studied in lesion mimic mutant 194. The plant height was slightly higher in mutant 194. In addition, the leaf spot per plant in mutant 194 was significantly higher than that in wild-type (WT). Antioxidant competence, as indicated by ROS accumulation, antioxidant enzymes activity, and the expression of antioxidant enzyme-encoding genes were also detected in mutant 194. Compared to the WT, mutant 194 displayed relatively higher accumulation of ROS and accompanied by lower activity of some antioxidant enzymes, and the down-regulation of antioxidant enzyme-encoding genes further demonstrated the deterioration of antioxidant competence in mutant 194. The results suggested that the lower antioxidant competence of mutant 194 could accumulate excessive ROS. The excessive ROS could induce PCD and has the potential in the disease resistant in mutant 194.

Bacillus firmus (SW5) augments salt tolerance in soybean (Glycine max L.) by modulating root system architecture, antioxidant defense systems and stress-responsive genes expression

Soil salinity is an adverse abiotic factor which reduces plant growth, yield and quality. Plant growth-promoting rhizobacteria (PGPR) have a great potential to enhance growth and alleviate saline stress effects without harming the environment via regulating physiological and molecular processes in plants. This study aimed at investigating Bacillus firmus SW5 effects on the performance of soybean (Glycine max L.) subjected to salt stress (0, 40 and 80 mM NaCl). Salinity stress mitigated the growth and biomass yield, root architecture traits, nutrient acquisition, chlorophyll level, transpiration rate (E), photosynthesis rate (Pn), stomatal conductance (gs), soluble proteins content, soluble sugars content and total phenolics and flavonoid contents of soybean plants. High salinity augmented the levels of osmolytes (glycine betaine and proline), hydrogen peroxide (H2O2), malondialdehyde (MDA) and the activities of antioxidant enzymes (APX, CAT, SOD and POD) in soybean plants. High salinity also induced the expression of antioxidant enzyme-encoding genes (APX, CAT, POD, Fe-SOD) and genes conferring tolerance to salinity (GmVSP, GmPHD2, GmbZIP62, GmWRKY54, GmOLPb, CHS) in soybean plants. On the other hand, inoculation of NaCl-stressed soybean plants with Bacillus firmus SW5 promoted the growth and biomass yield, chlorophyll synthesis, nutrient uptake, gas exchange parameters, osmolytes levels, total phenolic and flavonoid contents, and antioxidant enzymes activities, in comparison with the plants treated with NaCl alone. Bacillus firmus SW5 inoculation also significantly reduced the IC50 values for both DPPH and β-carotene-linoleic acid assays and indicated higher antioxidant activities in salt-stressed plants. Furthermore, contents of H2O2 and MDA were alleviated in salinity-stressed soybean plants inoculated with Bacillus firmus SW5, in comparison with those in plants exposed to NaCl alone. The antioxidant enzyme-encoding genes and stress-related genes exhibited the highest expression levels in soybean plants inoculated with Bacillus firmus SW5 and treated with 80 mM NaCl. Taken together, our results demonstrate the crucial role of Bacillus firmus SW5 in ameliorating the adverse effects of high salinity on soybean growth and performance via altering the root system architecture and inducing the antioxidant defense systems and stress-responsive genes expression.

Genetic Polymorphisms in Genes Encoding Antioxidant Enzymes Are Associated With Diabetic Retinopathy in Type 1 Diabetes

OBJECTIVEOxidative stress plays an important role in the development of microangiopathic complications in type 1 diabetes. We investigated polymorphic markers in genes encoding enzymes regulating production of reactive oxygen species in association with diabetic retinopathy or diabetic nephropathy.RESEARCH DESIGN AND METHODSA total of 124 patients with type 1 diabetes were investigated in this case-control study. All subjects were matched for sex, age, and duration of diabetes. Genotyping was conducted using real-time PCR for p.Val16Ala polymorphism in the MnSOD gene and c.C−262T in the promoter region of the CAT gene. Multiplex PCR method was used for determination of GSTM1 and GSTT1 polymorphic deletions. Fluorescence-labeled PCR amplicons and fragment analysis was used for assessing the number of pentanucleotide (CCTTT)n repeats in inducible nitric oxide synthase.RESULTSA positive association of MnSOD genotype Val/Val (odds ratio [OR] 2.49, 95% CI 1.00–6.16, P = 0.045) and GSTM1–1 genotype (2.63, 1.07–6.47, P = 0.031) with diabetic retinopathy but not with diabetic nephropathy was demonstrated. Additionally, the combination of the two genotypes conveyed an even higher risk (4.24, 1.37–13.40, P = 0.009). No other investigated genetic polymorphisms were associated with either diabetic retinopathy or diabetic nephropathy.CONCLUSIONSSelected polymorphisms in genes encoding MnSOD and GSTM1 could be added to a panel of genetic markers for identification of individuals with type 1 diabetes at an increased risk for developing diabetic retinopathy.

Expression of Genes Encoding Antioxidant Enzymes in Preimplantation Mouse and Cow Embryos and Primary Bovine Oviduct Cultures Employed for Embryo Coculture1

Preimplantation embryos from a variety of mammalian species contrast markedly in their response to culture in vitro. Murine preimplantation embryos display a wider tolerance than other mammalian species to culture environments, and this has contributed to the development of several effective defined culture media. Embryo coculture on somatic cells remains the most effective method of supporting reasonable rates of bovine preimplantation development in vitro. The patterns of gene expression for several antioxidant enzymes during preimplantation murine and bovine development were examined by use of the reverse transcription-polymerase chain reaction technique to determine whether the differential developmental capacity of mammalian preimplantation embryos in culture may reflect variations in the patterns of expression for a series of antioxidant enzymes. Transcripts for catalase, CuZn-containing superoxide dismutase (CuZn-SOD), Mn-SOD, glutathione peroxidase (GPX), and glutamylcysteine synthetase (GCS) were detected in mouse embryos at all stages of development regardless of in vivo or in vitro development. Preimplantation cow embryos produced by in vitro procedures expressed mRNAs for catalase, CuZn-SOD and GPX, whereas transcripts for Mn-SOD were not detected at any stage. GCS transcripts, although present in stages up to the morula, were not detected in cow blastocysts. Analysis of antioxidant gene expression in both bovine primary oviductal cell monolayer cultures and nonattached, ciliated oviductal cell vesicle cultures revealed a constitutive pattern of expression of all five enzymes for the 8-day culture interval. These experiments suggest that differences in gene expression may contribute to the variation in the ability of embryos to develop in vitro with respect to levels of oxygen and dependence on coculture.