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1
Vanacker, Hélène, Marjorie Guichard, Anne-Sophie Bohrer, and Emmanuelle Issakidis-Bourguet. "Redox Regulation of Monodehydroascorbate Reductase by Thioredoxin y in Plastids Revealed in the Context of Water Stress." Antioxidants 7, no. 12 (December 6, 2018): 183. http://dx.doi.org/10.3390/antiox7120183.
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Thioredoxins (TRXs) are key players within the complex response network of plants to environmental constraints. Here, the physiological implication of the plastidial y-type TRXs in Arabidopsis drought tolerance was examined. We previously showed that TRXs y1 and y2 have antioxidant functions, and here, the corresponding single and double mutant plants were studied in the context of water deprivation. TRX y mutant plants showed reduced stress tolerance in comparison with wild-type (WT) plants that correlated with an increase in their global protein oxidation levels. Furthermore, at the level of the main antioxidant metabolites, while glutathione pool size and redox state were similarly affected by drought stress in WT and trxy1y2 plants, ascorbate (AsA) became more quickly and strongly oxidized in mutant leaves. Monodehydroascorbate (MDA) is the primary product of AsA oxidation and NAD(P)H-MDA reductase (MDHAR) ensures its reduction. We found that the extractable leaf NADPH-dependent MDHAR activity was strongly activated by TRX y2. Moreover, activity of recombinant plastid Arabidopsis MDHAR isoform (MDHAR6) was specifically increased by reduced TRX y, and not by other plastidial TRXs. Overall, these results reveal a new function for y-type TRXs and highlight their role as major antioxidants in plastids and their importance in plant stress tolerance.
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Zhou, Fangfang, Bowen Zheng, Fei Wang, Aiping Cao, Shuangquan Xie, Xifeng Chen, Joel A. Schick, Xiang Jin, and Hongbin Li. "Genome-Wide Analysis of MDHAR Gene Family in Four Cotton Species Provides Insights into Fiber Development via Regulating AsA Redox Homeostasis." Plants 10, no. 2 (January 25, 2021): 227. http://dx.doi.org/10.3390/plants10020227.
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Monodehydroasorbate reductase (MDHAR) (EC1.6.5.4), a key enzyme in ascorbate-glutathione recycling, plays important roles in cell growth, plant development and physiological response to environmental stress via control of ascorbic acid (AsA)-mediated reduction/oxidation (redox) regulation. Until now, information regarding MDHAR function and regulatory mechanism in Gossypium have been limited. Herein, a genome-wide identification and comprehensive bioinformatic analysis of 36 MDHAR family genes in four Gossypium species, Gossypium arboreum, G. raimondii, G. hirsutum, and G. barbadense, were performed, indicating their close evolutionary relationship. Expression analysis of GhMDHARs in different cotton tissues and under abiotic stress and phytohormone treatment revealed diverse expression features. Fiber-specific expression analysis showed that GhMDHAR1A/D, 3A/D and 4A/D were preferentially expressed in fiber fast elongating stages to reach peak values in 15-DPA fibers, with corresponding coincident observances of MDHAR enzyme activity, AsA content and ascorbic acid/dehydroascorbic acid (AsA/DHA) ratio. Meanwhile, there was a close positive correlation between the increase of AsA content and AsA/DHA ratio catalyzed by MDHAR and fiber elongation development in different fiber-length cotton cultivars, suggesting the potential important function of MDHAR for fiber growth. Following H2O2 stimulation, GhMDHAR demonstrated immediate responses at the levels of mRNA, enzyme, the product of AsA and corresponding AsA/DHA value, and antioxidative activity. These results for the first time provide a comprehensive systemic analysis of the MDHAR gene family in plants and the four cotton species and demonstrate the contribution of MDHAR to fiber elongation development by controlling AsA-recycling-mediated cellular redox homeostasis.
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Park, Ae Kyung, Il-Sup Kim, Hackwon Do, Hyun Kim, Woong Choi, Seung-Woo Jo, Seung Chul Shin, Jun Hyuck Lee, Ho-Sung Yoon, and Han-Woo Kim. "Characterization and Structural Determination of Cold-Adapted Monodehydroascorbate Reductase, MDHAR, from the Antarctic Hairgrass Deschampsia Antarctica." Crystals 9, no. 10 (October 18, 2019): 537. http://dx.doi.org/10.3390/cryst9100537.
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Ascorbic acid (AsA) is an abundant component of plants and acts as a strong and active antioxidant. In order to maintain the antioxidative capacity of AsA, the rapid regeneration of AsA is regulated by dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR). To understand how MDHAR functions under extreme temperature conditions, this study characterized its biochemical properties and determined the crystal structure of MDHAR from the Antarctic hairgrass Deschampsia antarctica (DaMDHAR) at 2.2 Å resolution. This allowed for a structural comparison with the mesophilic MDHAR from Oryza sativa L. japonica (OsMDHAR). In the functional analysis, yeast cells expressing DaMDHAR were tolerant to freezing and thawing cycles. It is possible that the expression of DaMDHAR in yeast enhanced the tolerance for ROS-induced abiotic stress.
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Do, Hackwon, Il-Sup Kim, Young-Saeng Kim, Sun-Young Shin, Jin-Ju Kim, Ji-Eun Mok, Seong-Im Park, et al. "Purification, characterization and preliminary X-ray crystallographic studies of monodehydroascorbate reductase fromOryza sativaL.japonica." Acta Crystallographica Section F Structural Biology Communications 70, no. 9 (August 27, 2014): 1244–48. http://dx.doi.org/10.1107/s2053230x14015908.
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Monodehydroascorbate reductase (MDHAR; EC 1.6.5.4) is a key enzyme in the reactive oxygen species (ROS) detoxification system of plants. The participation of MDHAR in ascorbate (AsA) recycling in the ascorbate–glutathione cycle is important in the acquired tolerance of crop plants to abiotic environmental stresses. Thus, MDHAR represents a strategic target protein for the improvement of crop yields. Although physiological studies have intensively characterized MDHAR, a structure-based functional analysis is not available. Here, a cytosolic MDHAR (OsMDHAR) derived fromOryza sativaL.japonicawas expressed usingEscherichia colistrain NiCo21 (DE3) and purified. The purified OsMDHAR showed specific enzyme activity (approximately 380 U per milligram of protein) and was crystallized using the hanging-drop vapour-diffusion method at pH 8.0 and 298 K. The crystal diffracted to 1.9 Å resolution and contained one molecule in the asymmetric unit (the Matthews coefficientVMis 1.98 Å3 Da−1, corresponding to a solvent content of 38.06%) in space groupP41212 with unit-cell parametersa=b= 81.89,c= 120.4 Å. The phase of the OsMDHAR structure was resolved by the molecular-replacement method using a ferredoxin reductase fromAcidovoraxsp. strain KKS102 (PDB entry 4h4q) as a model.
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Truffault, Vincent, Noé Gest, Cécile Garchery, Alexandra Florian, Alisdair R. Fernie, Hélène Gautier, and Rebecca G. Stevens. "Reduction of MDHAR activity in cherry tomato suppresses growth and yield and MDHAR activity is correlated with sugar levels under high light." Plant, Cell & Environment 39, no. 6 (February 10, 2016): 1279–92. http://dx.doi.org/10.1111/pce.12663.
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Yoon, Seo-Kyung, Eung-Jun Park, Eun-Kyung Bae, Young-Im Choi, Joon-Hyeok Kim, and Hyoshin Lee. "Isolation and characterization of a monodehydroascorbate reductase gene in poplar (Populus alba × P. glandulosa)." Journal of Plant Biotechnology 41, no. 4 (December 31, 2014): 194–200. http://dx.doi.org/10.5010/jpb.2014.41.4.194.
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Maynard, Daniel, Vijay Kumar, Jens Spro�, and Karl-Josef Dietz. "12-Oxophytodienoic Acid Reductase 3 (OPR3) Functions as NADPH-Dependent α,β-Ketoalkene Reductase in Detoxification and Monodehydroascorbate Reductase in Redox Homeostasis." Plant and Cell Physiology 61, no. 3 (December 13, 2019): 584–95. http://dx.doi.org/10.1093/pcp/pcz226.
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Abstract Arabidopsis (Arabidopsis thaliana) 12-oxophytodienoic acid reductase isoform 3 (OPR3) is involved in the synthesis of jasmonic acid (JA) by reducing the α,β-unsaturated double bond of the cyclopentenone moiety in 12-oxophytodienoic acid (12-OPDA). Recent research revealed that JA synthesis is not strictly dependent on the peroxisomal OPR3. The ability of OPR3 to reduce trinitrotoluene suggests that the old yellow enzyme homolog OPR3 has additional functions. Here, we show that OPR3 catalyzes the reduction of a wide spectrum of electrophilic species that share a reactivity toward the major redox buffers glutathione (GSH) and ascorbate (ASC). Furthermore, we show that 12-OPDA reacts with ASC to form an ASC-12-OPDA adduct, but in addition OPR3 has the ability to regenerate ASC from monodehydroascorbate. The presented data characterize OPR3 as a bifunctional enzyme with NADPH-dependent α,β-ketoalkene double-bond reductase and monodehydroascorbate reductase activities (MDHAR). opr3 mutants showed a slightly less-reduced ASC pool in leaves in line with the MDHAR activity of OPR3 in vitro. These functions link redox homeostasis as mediated by ASC and GSH with OPR3 activity and metabolism of reactive electrophilic species.
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Lunde, Christina, Ute Baumann, Neil J. Shirley, Damian P. Drew, and Geoffrey B. Fincher. "Gene Structure and Expression Pattern Analysis of Three Monodehydroascorbate Reductase (Mdhar) Genes in Physcomitrella patens: Implications for the Evolution of the MDHAR Family in Plants*." Plant Molecular Biology 60, no. 2 (January 2006): 259–75. http://dx.doi.org/10.1007/s11103-005-3881-8.
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Acosta-Motos, José Ramón, Laura Noguera-Vera, Gregorio Barba-Espín, Abel Piqueras, and José A. Hernández. "Antioxidant Metabolism and Chlorophyll Fluorescence during the Acclimatisation to Ex Vitro Conditions of Micropropagated Stevia rebaudiana Bertoni Plants." Antioxidants 8, no. 12 (December 3, 2019): 615. http://dx.doi.org/10.3390/antiox8120615.
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In this study, the functioning of antioxidant metabolism and photosynthesis efficiency during the acclimatisation of Stevia rebaudiana plants to ex vitro conditions was determined. A high percentage of acclimatised plants (93.3%) was obtained after four weeks. According to the extent of lipid peroxidation, an oxidative stress occurred during the first hours of acclimatisation. A lower activity of monodehydroascorbate reductase (MDHAR) than dehydroascorbate reductase (DHAR) was observed after 2 days of acclimatisation. However, after 7 days of acclimatisation, stevia plants activated the MDHAR route to recycle ascorbate, which is much more efficient energetically than the DHAR route. Superoxide dismutase and catalase activities showed a peak of activity after 7 days of acclimatisation, suggesting a protection against reactive oxygen species. Peroxidase activity increased about 2-fold after 2 days of acclimatisation and remained high until day 14, probably linked to the cell wall stiffening and the lignification processes. In addition, a progressive increase in the photochemical quenching parameters and the electronic transport rate was observed, coupled with a decrease in the non-photochemical quenching parameters, which indicate a progressive photosynthetic efficiency during this process. Taken together, antioxidant enzymes, lipid peroxidation, and chlorophyll fluorescence are proven as suitable tools for the physiological state evaluation of micropropagated plants during acclimatisation to ex vitro conditions.
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Liu, Xiumei, Lu Wang, Haoran Cui, Hong Zhu, Sisheng Bi, Zhihao Zhang, Shiyuan Meng, Chengdong Song, Huatian Wang, and Fengyun Ma. "Effects of magnetic treatment on the ascorbate–glutathione cycle and endogenous hormone levels in Populus × euramericana ‘Neva’ under cadmium stress." Canadian Journal of Forest Research 49, no. 9 (September 2019): 1147–58. http://dx.doi.org/10.1139/cjfr-2018-0466.
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Cadmium (Cd) contamination in soil has become a serious worldwide environmental and health problem. Cd is easily taken up by plants and translocated to aboveground tissues. A pot experiment was carried out to explore the role of the ascorbate–glutathione (AsA–GSH) cycle and endogenous hormones in enhancing Cd tolerance and promoting translocation of Cd in one-year-old seedlings of Populus × euramericana ‘Neva’. The antioxidant substances ascorbic acid (AsA), dehydroascorbic acid (DHA), glutathione (GSH), and oxidized glutathione (GSSG); the activities of the antioxidant enzymes ascorbic acid peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and dehydroascorbic acid reductase (DHAR); the levels of the endogenous hormones indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellin (GA3), and zeatin riboside (ZR); and the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2) were investigated after 30 days of irrigation with half-Hoagland solution containing 0 or 100 μmol·L–1 Cd(NO3)2 under magnetic treatment (MT) or nonmagnetic treatment (NMT). The results were as follows. (i) Compared with NMT, MT increased the AsA levels in roots compared with those in leaves under Cd stress, whereas it increased the DHA levels in the leaves but decreased the DHA levels in the roots. The GSH and GSSG levels both increased by 8%–151% under MT. (ii) MT inhibited the APX activity in blades and roots, and a similar effect was observed on the foliar activities of GR and MDHAR, with a decrease of 8%–50%; however, MT increased the activation of DHAR in the blades and GR in the roots. In addition, compared with NMT, MT increased the activities of GR, MDHAR, and DHAR by 19%–285% in Populus (poplar). (iii) With the exogenous addition of Cd, the Cd accumulation and biological transport coefficient of Cd from roots to leaves (S/R) were enhanced in poplar, accompanied by increased levels of H2O2 and MDA due to MT. (iv) The levels of IAA, ABA, GA, and ZR were inhibited by 19%–95% in the leaves following MT. In contrast, the levels of these endogenous hormones were increased by 18%–203% in the roots following MT. (v) MT improved the seedling growth of poplar, with an increase of 0.4%–90%, compared with that of the NMT. The ground diameter and number of root tips showed the greatest increases, with average ratios of 29% and 87%, respectively. These results suggested a large increase in AsA and decreases in poplar antioxidant enzymes, especially in the leaves, with a high GSH level. In this review, we concluded that the antioxidant substance GSH plays an important role in the AsA–GSH cycle following exposure to a magnetic field under Cd stress. Additionally, the roots play a major role in eliminating oxygen free radicals by regulating the levels and ratios of various endogenous hormones. Moreover, magnetization could alleviate Cd-induced oxidative stress by stimulating MDHAR, DHAR, and GR activities; enhance the defense capability of the AsA–GSH cycle; and maintain normal physiological metabolism in poplar.
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Simon, Lins, and Akkara Yusuf. "Effects of salt stress on antioxidant and ascorbate glutathione cycle enzyme activities in Pokkali rice varieties – Vytilla 1-9." Plant Science Today 7, no. 3 (July 1, 2020): 341–48. http://dx.doi.org/10.14719/pst.2020.7.3.701.
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The enzymatic and non-enzymatic antioxidant levels in the released salt tolerant Pokkali, (vytilla, VTL 1-9) varieties were studied under different NaCl concentrations (0-150 mM NaCl). The specific activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate-glutathione cycle enzymes and non-enzymatic antioxidants like superoxide (O2-), hydrogen peroxide (H2O2), malondialdehyde (MDA), glutathione (GSH) and ascorbic acid (AsA) was determined in plants exposed to salt stress. IR-28 was used as positive control and the VTL varieties were used as negative control. The H2O2 and superoxide (O2-) contents were higher in IR-28 at all the applied concentrations of NaCl. The VTL varieties without salt treatment did not evoke any response substantiating the role of salt priming in antioxidant signalling. The MDA contents were higher in the positive and negative control. MDA content was reduced in the NaCl treated VTL varieties. In the positive and negative control varieties, the quantity of ascorbate and glutathione contents were lesser and upregulated in salt treated VTL varieties. Highest H2O2 content was observed in 150 mM NaCl treatment. The H2O2 contents decreased with the increase in all concentrations of NaCl and lowest H2O2 contents was observed in VTL-1 and highest in VTL-2 and VTL-8 treated with 150 mM NaCl. Superoxide contents varied in all the nine varieties depending on the salt concentration. The SOD levels in all the varieties showed a positive correlation with the superoxide and H2O2 content. Lesser quantities of SOD, CAT and the ascorbate - glutathione cycle enzymes were expressed in the positive and negative control. The increased NaCl concentration (25-150 mM) upregulated antioxidant and ascorbate-glutathione cycle enzymes in the VTL varieties. The APX activity was lower in the control and salt treated plants. The GR activity increased linearly in all the varieties with respect to salt concentrations. The MDHAR and DHAR activities showed marginally linear increase, with all concentrations of NaCl. The APX activity was similar or lower to MDHAR activity while DHAR activity was similar to MDHAR activity. The results of the present study reveals the higher levels of enzymatic and non-enzymatic antioxidants under salt stress reflect the salt tolerance potential of pokkali varieties mediated by the up regulation of ROS scavenging enzymes.
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Terzi, Rabiye, Güler Saruhan, Funda Güven, and Asim Kadioglu. "Alpha lipoic acid treatment induces the antioxidant system and ameliorates lipid peroxidation in maize seedlings under osmotic stress." Archives of Biological Sciences 70, no. 3 (2018): 503–11. http://dx.doi.org/10.2298/abs171218011t.
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Plants are markedly affected by drought stress caused by fluctuations in global climate, reduction in rainfall and a decrease in soil fertility. Therefore, some mechanistic strategies to cope with adverse effects of drought stress are needed. Alpha lipoic acid (ALA), a potent antioxidant molecule, is known to function in abiotic stress tolerance. In the current study, we investigated the ALA-stimulated physiological role in tolerance to osmotic stress induced by polyethylene glycol in two maize (Zea mays L.) cultivars (cv. Helen and cv. Akpinar). Application of ALA increased the leaf water potential of maize cultivars under stressful and stress-free conditions but decreased lipid peroxidation and the hydrogen peroxide (H2O2) content. Additionally, enhanced activity of the antioxidant defense system was observed following ALA application. Exogenous ALA elevated the activities of enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), glutathione reductase (GR) and monodehydroascorbate reductase (MDHAR) under osmotic stress as compared to seedlings not exposed to ALA. Conversely, ascorbate peroxidase (APX) activity was decreased by ALA application in both cultivars. Higher GR and MDHAR activities of both cultivars were simultaneously observed in ALA treatments under osmotic stress. Taken together, the data indicated that exogenous ALA may function in arranging resilience against osmotic stress by reducing oxidative damage through induction of the antioxidant machinery in maize cultivars.
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LÓPEZ-HUERTAS, Eduardo, Francisco J. CORPAS, Luisa M. SANDALIO, and Luis A. DEL RÍO. "Characterization of membrane polypeptides from pea leaf peroxisomes involved in superoxide radical generation." Biochemical Journal 337, no. 3 (January 25, 1999): 531–36. http://dx.doi.org/10.1042/bj3370531.
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The production of superoxide radicals (O2-•) and the activities of ferricyanide reductase and cytochrome c reductase were investigated in peroxisomal membranes from pea (Pisum sativum L.) leaves using NADH and NADPH as electron donors. The generation of O2-• by peroxisomal membranes was also assayed in native polyacrylamide gels using an in situ staining method with NitroBlue Tetrazolium (NBT). When peroxisomal membranes were assayed under native conditions using NADH or NADPH as inducer, two different O2-•-dependent Formazan Blue bands were detected. Analysis by SDS/PAGE of these bands demonstrated that the NADH-induced NBT reduction band contained several polypeptides (PMP32, PMP61, PMP56 and PMP18, where PMP is peroxisomal membrane polypeptide and the number indicates molecular mass in kDa), while the NADPH-induced band was due exclusively to PMP29. PMP32 and PMP29 were purified by preparative SDS/PAGE and electroelution. Reconstituted PMP29 showed cytochrome c reductase activity and O2-• production, and used NADPH specifically as electron donor. PMP32, however, had ferricyanide reductase and cytochrome c reductase activities, and was also able to generate O2-• with NADH as electron donor, whereas NADPH was not effective as an inducer. The reductase activities of, and O2-• production by, PMP32 were inhibited by quinacrine. Polyclonal antibodies against cucumber monodehydroascorbate reductase (MDHAR) recognized PMP32, and this polypeptide is likely to correspond to the MDHAR reported previously in pea leaf peroxisomal membranes.
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Yu, Xiaofang, Yujia Liu, Panpan Cao, Xiaoxuan Zeng, Bin Xu, Fuwen Luo, Xuan Yang, et al. "Morphological Structure and Physiological and Biochemical Responses to Drought Stress of Iris japonica." Plants 12, no. 21 (October 30, 2023): 3729. http://dx.doi.org/10.3390/plants12213729.
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Drought is among the most important abiotic stresses on plants, so research on the physiological regulation mechanisms of plants under drought stress can critically increase the economic and ecological value of plants in arid regions. In this study, the effects of drought stress on the growth status and biochemical indicators of Iris japonica were explored. Under drought stress, the root system, leaves, rhizomes, and terrestrial stems of plants were sequentially affected; the root system was sparse and slender; and the leaves lost their luster and gradually wilted. Among the physiological changes, the increase in the proline and soluble protein content of Iris japonica enhanced the cellular osmotic pressure and reduced the water loss. In anatomical structures, I. japonica chloroplasts were deformed after drought treatment, whereas the anatomical structures of roots did not substantially change. Plant antioxidant systems play an important role in maintaining cellular homeostasis; but, as drought stress intensified, the soluble sugar content of terrestrial stems was reduced by 55%, and the ascorbate peroxidase, glutathione reductase, and monodehydroascorbate reductase (MDHAR) activities of leaves and the MDHAR activity of roots were reduced by 29%, 40%, 22%, and 77%, respectively. Overall, I. japonica was resistant to 63 days of severe drought stress and resisted drought through various physiological responses. These findings provide a basis for the application of I. japonica in water-scarce areas.
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Espinosa, Francisco, Alfonso Ortega, Francisco L. Espinosa-Vellarino, and Inmaculada Garrido. "Effect of Thallium(I) on Growth, Nutrient Absorption, Photosynthetic Pigments, and Antioxidant Response of Dittrichia Plants." Antioxidants 12, no. 3 (March 9, 2023): 678. http://dx.doi.org/10.3390/antiox12030678.
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Dittrichia plants were exposed to thallium (Tl) stress (10, 50, and 100 µM) for 7 days. The Tl toxicity altered the absorption and accumulation of other nutrients. In both the roots and the leaves, there was a decline in K, Mg, and Fe content, but an increase in Ca, Mn, and Zn. Chlorophylls decreased, as did the photosynthetic efficiency, while carotenoids increased. Oxidative stress in the roots was reflected in increased lipid peroxidation. There was more production of superoxide (O2.−), hydrogen peroxide (H2O2), and nitric oxide (NO) in the roots than in the leaves, with increases in both organs in response to Tl toxicity, except for O2.− production in the roots, which fluctuated. There was increased hydrogen sulfide (H2S) production, especially in the leaves. Superoxide dismutase (SOD), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), and glutathione reductase (GR) showed increased activities, except for APX and MDHAR in the roots and GR in the leaves. The components of the ascorbate–glutathione cycle were affected. Thus, ascorbate (AsA) increased, while dehydroascorbate (DHA), reduced glutathione (GSH), and oxidized glutathione (GSSG) decreased, except for in the roots at 100 µM Tl, which showed increased GSH. These Tl toxicity-induced alterations modify the AsA/DHA and GSH/GSSG redox status. The NO and H2S interaction may act by activating the antioxidant system. The effects of Tl could be related to its strong affinity for binding with -SH groups, thus altering the functionality of proteins and the cellular redox state.
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Akter, Sharmin, Md Golam Rasul, Mohammad Zakaria, Md Mahathir Sarker, Irin Sultana Nila, Sudipta Dutta, Md Masudul Haque, and Md Motiar Rohman. "Effect of Polyamine on Pigmentation, Reactive Oxidative Species and Antioxidant under Drought in Maize (Zea mays L.)." Turkish Journal of Agriculture - Food Science and Technology 6, no. 7 (May 31, 2019): 799. http://dx.doi.org/10.24925/turjaf.v6i7.799-811.1493.
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To examine polyamines (PAs) effect in modulating the drought induced by polyethylene glycol (PEG) in maize (Zea mays L.) seedlings (variety Khoibhutta, 8 day seedlings grown in petri dish in incubator) were subjected to 20% PEG (polyethylene glycol) followed by 20 µmol PAs, Putrescine (Put), Spermidine (Spd) and Spermine (Spm) with PEG solution for 48 hours. Sharp decrease in Relative Water Content (RWC), Chl a, Chl b, carotenoid (Car) and total pigment content was observed under drought compared to control condition, while PAs application reversed their decreasing trends. PEG significantly increased Reactive Oxidative Species (ROS) [superoxide (O2•−) and H2O2], Methyl Glyoxal (MG), Melondialdehyde (MDA) and Lipoxigenase (LOX) activity, while Pas decreased the contents considerably (except MG) as compared to those under drought. Drought increased proline content, which was further augmented in PA treatments. PAs failed to incline glyoxalase’s (Gly-I and Gly-II) activities, reduced under PEG. The activity and western blot confirmed the accumulation of Glutathione S-Transferase (GST) under drought, but PAs failed to augment the activity. Ascorbic Acid (AsA) and Glutathione (GSH) got oxidized into Dehydroascorbate (DHA) and oxidized Glutathione (GSSG) under drought but PAs effectively maintained homeostasis. Superoxide Dismutase (SOD), Peroxidase (POD), Ascorbate Peroxidase (APX), Glutathione Peroxidase (GPX), Monodehydroascorbatereductase (MDHAR), Dehydroascorbatereductase (DHAR), and Glutathione Reductase (GR) inclined in drought stressed seedlings, while Catalase (CAT) activity decreased under drought. PAs addition increased SOD, POD, GPX, CAT, MDHAR, and GR activities, but declined DHAR activity. These findings suggested important role of PAs in increasing tolerance under short term drought by modulating antioxidant effect.
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Choudhury, Shuvasish, Muhammed Khairujjaman Mazumder, Debojyoti Moulick, Parul Sharma, Sandeep Kumar Tata, Dibakar Ghosh, Hayssam M. Ali, et al. "A Computational Study of the Role of Secondary Metabolites for Mitigation of Acid Soil Stress in Cereals Using Dehydroascorbate and Mono-Dehydroascorbate Reductases." Antioxidants 11, no. 3 (February 25, 2022): 458. http://dx.doi.org/10.3390/antiox11030458.
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The present study investigates the potential ameliorative role of seven secondary metabolites, viz., ascorbate (AsA), reduced glutathione (GSH), jasmonic acid (JA), salicylic acid (SA), serotonin (5-HT), indole–3–acetic acid (IAA) and gibberellic acid (GA3), for mitigation of aluminium (Al3+) and manganese (Mn2+) stress associated with acidic soils in rice, maize and wheat. The dehydroascorbate reductase (DHAR) and mono-dehydroascorbate reductase (MDHAR) of the cereals were used as model targets, and the analysis was performed using computational tools. Molecular docking approach was employed to evaluate the interaction of these ions (Al3+ and Mn2+) and the metabolites at the active sites of the two target enzymes. The results indicate that the ions potentially interact with the active sites of these enzymes and conceivably influence the AsA–GSH cycle. The metabolites showed strong interactions at the active sites of the enzymes. When the electrostatic surfaces of the metabolites and the ions were generated, it revealed that the surfaces overlap in the case of DHAR of rice and wheat, and MDHAR of rice. Thus, it was hypothesized that the metabolites may prevent the interaction of ions with the enzymes. This is an interesting approach to decipher the mechanism of action of secondary metabolites against the metal or metalloid - induced stress responses in cereals by aiming at specific targets. The findings of the present study are reasonably significant and may be the beginning of an interesting and useful approach towards comprehending the role of secondary metabolites for stress amelioration and mitigation in cereals grown under acidic soil conditions.
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Altaf, Muhammad Ahsan, Rabia Shahid, Ming-Xun Ren, Safina Naz, Muhammad Mohsin Altaf, Latif Ullah Khan, Rahul Kumar Tiwari, et al. "Melatonin Improves Drought Stress Tolerance of Tomato by Modulating Plant Growth, Root Architecture, Photosynthesis, and Antioxidant Defense System." Antioxidants 11, no. 2 (February 3, 2022): 309. http://dx.doi.org/10.3390/antiox11020309.
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Tomato is an important vegetable that is highly sensitive to drought (DR) stress which impairs the development of tomato seedlings. Recently, melatonin (ME) has emerged as a nontoxic, regulatory biomolecule that regulates plant growth and enhances the DR tolerance mechanism in plants. The present study was conducted to examine the defensive role of ME in photosynthesis, root architecture, and the antioxidant enzymes’ activities of tomato seedlings subjected to DR stress. Our results indicated that DR stress strongly suppressed growth and biomass production, inhibited photosynthesis, negatively affected root morphology, and reduced photosynthetic pigments in tomato seedlings. Per contra, soluble sugars, proline, and ROS (reactive oxygen species) were suggested to be improved in seedlings under DR stress. Conversely, ME (100 µM) pretreatment improved the detrimental-effect of DR by restoring chlorophyll content, root architecture, gas exchange parameters and plant growth attributes compared with DR-group only. Moreover, ME supplementation also mitigated the antioxidant enzymes [APX (ascorbate peroxidase), CAT (catalase), DHAR (dehydroascorbate reductase), GST (glutathione S-transferase), GR (glutathione reductase), MDHAR (monodehydroascorbate reductase), POD (peroxidase), and SOD (superoxide dismutase)], non-enzymatic antioxidant [AsA (ascorbate), DHA (dehydroascorbic acid), GSH (glutathione), and GSSG, (oxidized glutathione)] activities, reduced oxidative damage [EL (electrolyte leakage), H2O2 (hydrogen peroxide), MDA (malondialdehyde), and O2•− (superoxide ion)] and osmoregulation (soluble sugars and proline) of tomato seedlings, by regulating gene expression for SOD, CAT, APX, GR, POD, GST, DHAR, and MDHAR. These findings determine that ME pretreatment could efficiently improve the seedlings growth, root characteristics, leaf photosynthesis and antioxidant machinery under DR stress and thereby increasing the seedlings’ adaptability to DR stress.
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Gang, Huixin, Danni Zhang, Xiaojuan Sun, Junwei Huo, and Dong Qin. "Influences of Shading on Ascorbic Acid Biosynthesis of Blackcurrant (Ribes nigrum L.)." Forests 13, no. 7 (July 17, 2022): 1127. http://dx.doi.org/10.3390/f13071127.
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Cultivation conditions may greatly affect fruit quality, especially in the accumulation of functional metabolites. Blackcurrant fruits (Ribes nigrum L.) have high ascorbic acid (AsA) concentrations. The purpose of the current study was to investigate the influence of different shading treatments (full sunlight, and 40% and 60% sunlight) on the fruits’ maturity, and on the levels of fruit firmness, soluble solid, AsA, and enzyme activity involved in AsA biosynthesis and recycling in two blackcurrant (Ribes nigrum) cultivars, ‘Heifeng’ and ‘Adelinia’. Shading conditions of 40% and 60% sunlight delayed fruit ripening and increased fruit firmness in both ‘Adelinia’ and ‘Heifeng’. Soluble solids in ‘Adelinia’ were markedly reduced by shading compared with ‘Heifeng’. Compared with full sunlight, the AsA content was significantly decreased in the ripe fruits under the 40% and 60% shading treatments. Additionally, the AsA content was decreased during the fruit development process under the 60% shading treatment, which was associated with the reduced activity of the enzymes monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione oxidoreductase (GR), ascorbate peroxidase (APX), and L-galactose dehydrogenase (GalDH) involved in the biosynthesis and recycling pathway of AsA. The correlation analysis results showed that the activity of MDHAR, DHAR, GR, APX, and GalDH was significantly positively correlated with AsA concentrations during the 60% shading treatment in ‘Adelinia’ and ‘Heifeng’ fruits, suggesting that AsA biosynthesis and recycling were affected and the two cultivars have similar mechanisms to deal with shading. Our results not only provide a better understanding of the regulation mechanism of AsA accumulation under shading, but also provide a theoretical basis for taking effective cultivation measures aimed at the improvement of AsA levels in blackcurrant fruits.
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Rahman, Mira, Khussboo Rahman, Khadeja Sultana Sathi, Md Mahabub Alam, Kamrun Nahar, Masayuki Fujita, and Mirza Hasanuzzaman. "Supplemental Selenium and Boron Mitigate Salt-Induced Oxidative Damages in Glycine max L." Plants 10, no. 10 (October 19, 2021): 2224. http://dx.doi.org/10.3390/plants10102224.
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The present investigation was executed with an aim to evaluate the role of exogenous selenium (Se) and boron (B) in mitigating different levels of salt stress by enhancing the reactive oxygen species (ROS) scavenging, antioxidant defense and glyoxalase systems in soybean. Plants were treated with 0, 150, 300 and 450 mM NaCl at 20 days after sowing (DAS). Foliar application of Se (50 µM Na2SeO4) and B (1 mM H3BO3) was accomplished individually and in combined (Se+B) at three-day intervals, at 16, 20, 24 and 28 DAS under non-saline and saline conditions. Salt stress adversely affected the growth parameters. In salt-treated plants, proline content and oxidative stress indicators such as malondialdehyde (MDA) content and hydrogen peroxide (H2O2) content were increased with the increment of salt concentration but the relative water content decreased. Due to salt stress catalase (CAT), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glyoxalase I (Gly I) and glyoxalase II (Gly II) activity decreased. However, the activity of ascorbate peroxidase (APX), glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST) and peroxidase (POD) increased under salt stress. On the contrary, supplementation of Se, B and Se+B enhanced the activities of APX, MDHAR, DHAR, GR, CAT, GPX, GST, POD, Gly I and Gly II which consequently diminished the H2O2 content and MDA content under salt stress, and also improved the growth parameters. The results reflected that exogenous Se, B and Se+B enhanced the enzymatic activity of the antioxidant defense system as well as the glyoxalase systems under different levels of salt stress, ultimately alleviated the salt-induced oxidative stress, among them Se+B was more effective than a single treatment.
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Xu, Junrong, Zhien Wei, Xuefang Lu, Yunzhi Liu, Wenjin Yu, and Changxia Li. "Involvement of Nitric Oxide and Melatonin Enhances Cadmium Resistance of Tomato Seedlings through Regulation of the Ascorbate–Glutathione Cycle and ROS Metabolism." International Journal of Molecular Sciences 24, no. 11 (May 31, 2023): 9526. http://dx.doi.org/10.3390/ijms24119526.
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Melatonin (MT) and nitric oxide (NO) act as signaling molecules that can enhance cadmium (Cd) stress resistance in plants. However, little information is available about the relationship between MT and NO during seedling growth under Cd stress. We hypothesize that NO may be involved in how MT responds to Cd stress during seedling growth. The aim of this study is to evaluate the relationship and mechanism of response. The results indicate that different concentrations of Cd inhibit the growth of tomato seedlings. Exogenous MT or NO promotes seedling growth under Cd stress, with a maximal biological response at 100 μM MT or NO. The promotive effects of MT-induced seedling growth under Cd stress are suppressed by NO scavenger 2-4-carboxyphenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (cPTIO), suggesting that NO may be involved in MT-induced seedling growth under Cd stress. MT or NO decreases the content of hydrogen peroxide (H2O2), malonaldehyde (MDA), dehydroascorbic acid (DHA), and oxidized glutathione (GSSG); improves the content of ascorbic acid (AsA) and glutathione (GSH) and the ratios of AsA/DHA and GSH/GSSG; and enhances the activities of glutathione reductase (GR), monodehydroascorbic acid reductase (MDHAR), dehydroascorbic acid reductase (DHAR), ascorbic acid oxidase (AAO), and ascorbate peroxidase (APX) to alleviate oxidative damage. Moreover, the expression of genes associated with the ascorbate–glutathione (AsA-GSH) cycle and reactive oxygen species (ROS) are up-regulated by MT or NO under Cd conditions, including AAO, AAOH, APX1, APX6, DHAR1, DHAR2, MDHAR, and GR. However, NO scavenger cPTIO reverses the positive effects regulated by MT. The results indicate that MT-mediated NO enhances Cd tolerance by regulating AsA-GSH cycle and ROS metabolism.
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Lu, Ninghai, Limin Wu, Xiaoqing Zhang, Yanyan Zhang, and Changjuan Shan. "Selenium improves the content of vitamin C in the fruit of strawberry by regulating the enzymes responsible for vitamin C metabolism." Plant, Soil and Environment 68, No. 4 (April 25, 2022): 205–11. http://dx.doi.org/10.17221/48/2022-pse.
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To investigate how sodium selenite (Na<sub>2</sub>SeO<sub>3</sub>) regulated the content of vitamin C (Vc) in strawberry fruit, we explored the effects of Na<sub>2</sub>SeO<sub>3</sub> on the enzymes responsible for Vc metabolism. The findings showed that<br /> 10 mg/L Na<sub>2</sub>SeO<sub>3</sub> improved the activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), l-galactono-1,4-lactone dehydrogenase (GalLDH) at periods of young fruit (YFP), small fruit (SFP), middle fruit (MFP), large fruit (LFP), white fruit (WFP), colour-changed fruit (CFP) and ripen fruit (RFP). 30 mg/L Na<sub>2</sub>SeO<sub>3</sub> improved the activities of APX, MDHAR, GR and GaILDH at YFP, LFP, WFP, CFP and RFP. 60 mg/L Na<sub>2</sub>SeO<sub>3</sub> improved the activities of MDHAR, GR and GaILDH at all periods studied. In addition, 10 mg/L Na<sub>2</sub>SeO<sub>3</sub> decreased the activity of ascorbate oxidase (AAO) at WFP and CFP. 30 mg/L Na<sub>2</sub>SeO<sub>3</sub> decreased AAO activity at MFP, LFP, WFP and CFP. 60 mg/L Na<sub>2</sub>SeO<sub>3</sub> decreased AAO activity at YFP, SFP, MFP, LFP, WFP and CFP. Meanwhile, all concentrations of Na<sub>2</sub>SeO<sub>3</sub> significantly increased the contents of Vc and Se. Among different concentrations, 30 mg/L Na<sub>2</sub>SeO<sub>3</sub> had better effects on the enzymes responsible for Vc metabolism, which further improved Vc content in strawberry fruit. Besides, all concentrations of Na<sub>2</sub>SeO<sub>3</sub> increased fruit average weight, number of fruits per plant and fruit yield, compared with control. The above results indicated that Na<sub>2</sub>SeO<sub>3</sub> could improve the content of Vc in fruit and fruit yield of strawberries, especially for 30 mg/L Na<sub>2</sub>SeO<sub>3</sub>.
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Haroldsen, Victor M., Cecilia L. Chi-Ham, Shashank Kulkarni, Argelia Lorence, and Alan B. Bennett. "Constitutively expressed DHAR and MDHAR influence fruit, but not foliar ascorbate levels in tomato." Plant Physiology and Biochemistry 49, no. 10 (October 2011): 1244–49. http://dx.doi.org/10.1016/j.plaphy.2011.08.003.
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Cocetta, Giacomo, Ilaria Mignani, and Anna Spinardi. "Ascorbic Acid Content in ‘Passe-Crassane’ Winter Pear as Affected by 1-Methylcyclopropene during Cold Storage and Shelf Life." HortScience 51, no. 5 (May 2016): 543–48. http://dx.doi.org/10.21273/hortsci.51.5.543.
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‘Passe-Crassane’ is a winter pear which requires a cold storage period to produce ethylene and properly ripen. In this study, the effects of 1-methylcyclopropene (1-MCP), an ethylene perception inhibitor, were studied during cold storage (30, 60, 90, and 135 days) and shelf life at 20 °C (30 days) of ‘Passe-Crassane’ pears. Ethylene accumulation was monitored and quality parameters were measured. Oxidative stress of fruit was estimated by measuring lipid peroxidation. The cell antioxidant status was assayed determining ascorbic acid (AsA) content and the activities of the enzymes ascorbate peroxidase (APX), monodehyroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) involved in its oxidation and recycling. AsA content was positively affected by higher temperature (20 °C) and by 1-MCP after 90 days of storage. This effect was more evident after shelf life. Thiobarbituric acid reactive substances (TBARS) increased in pears kept at 20 °C and in treated pears, starting from 60 days of cold storage and remained elevated after shelf life. Although during storage 1-MCP enhanced the activities of APX and DHAR only at 90 days, after shelf life the effect on APX, MDHAR, and DHAR activities was more pronounced and enzyme activities were higher in treated pears sampled after 60 and 90 days of storage. The results indicate that 1-MCP has a beneficial effect on the antioxidant potential of winter pears: it maintained high AsA levels throughout storage and shelf life and improved the enzymatic mechanisms of AsA recycling, especially after shelf life. The effect of 1-MCP on pear ripening may not be solely due to its action on ethylene but also to an increase in antioxidant defense. A stress response linked to lipid peroxidation is triggered by the interaction of cold temperatures and treatment as ‘Passe-Crassane’ pears acquires ripening competence. However, it may be compensated by the high AsA content.
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Hodges, D. Mark, and Charles F. Forney. "Postharvest Ascorbate Metabolism in Two Cultivars of Spinach Differing in Their Senescence Rates." Journal of the American Society for Horticultural Science 128, no. 6 (November 2003): 930–35. http://dx.doi.org/10.21273/jashs.128.6.0930.
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Rapidly declining levels of ascorbate (vitamin C) have been associated with advancing senescence and postharvest quality loss in spinach (Spinacia oleracea L.). To further explore the association between ascorbate metabolism and senescence, two cultivars of spinach previously shown to differ in their postharvest senescence rates were grown under controlled conditions (18 °C, 14 light: 10 dark photocycle) and harvested 6 weeks after planting. Detached leaves of `Spokane F1' (relatively fast senescence rate) and `BJ412 Sponsor'(relatively slow senescence rate) were bagged and placed in the dark at 10 °C. Samples were removed on days 0, 7, 14, 21, and 28, and analyzed for activities of L-galactono-γ-lactone dehydrogenase (GLDH), ascorbate peroxidase (ASPX), ascorbate oxidase (AAO), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR), and levels of ascorbate [reduced (AsA) and oxidized (DHA)] and malondialdehyde (MDA) (estimator of lipid peroxidation). Oxidative stress, as estimated by MDA levels, steadily increased in both spinach cultivars during storage, but increased more in `Spokane'than in `Sponsor'. GLDH activities peaked on day 14 for both cultivars and leveled off thereafter, while activities of ASPX, DHAR, and MDHAR declined during storage. ASPX activities were lower in `Spokane'than in `Sponsor'after day 21. No difference in AAO activities was noted between `Sponsor'and `Spokane'during storage. Total ascorbate concentrations declined in both cultivars on day 14 after which no further decreases were noted, while DHA/AsA ratios increased during storage. Early in the storage regime (days 0 and 7), ascorbate levels were lower in `Spokane'than in `Sponsor. GLDH activities may have increased as part of a strategy to maintain the ascorbate pool during escalating oxidative stress. However, decreased levels of ascorbate suggests that, even though ascorbate biosynthesis was increased, ascorbate was being degraded, possibly through hydrolysis of DHA to 2,3-diketogulonate. Initially lower levels of ascorbate (days 0 and 7) and lower activities of ASPX (day 28) in `Spokane' may have resulted in comparatively greater susceptibility of this cultivar to oxidative stress than `Sponsor'.
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Rohman, Md Motiar, Md Robyul Islam, Mahmuda Binte Monsur, Mohammad Amiruzzaman, Masayuki Fujita, and Mirza Hasanuzzaman. "Trehalose Protects Maize Plants from Salt Stress and Phosphorus Deficiency." Plants 8, no. 12 (December 4, 2019): 568. http://dx.doi.org/10.3390/plants8120568.
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This study is undertaken to elucidate the role of trehalose (Tre) in mitigating oxidative stress under salinity and low P in maize. Eight-day-old maize seedlings of two maize varieties, BARI Hybrid Maize-7 and BARI Hybrid Maize-9, were subjected to salinity (150 mM NaCl), low P (5 µM KH2PO4) and their combined stress with or without 10 mM Tre for 15 d. Salinity and combined stress significantly inhibited the shoot length, root length, and root volume, whereas low P increased the root length and volume in both genotypes. Exogenous Tre in the stress treatments increased all of the growth parameters as well as decreased the salinity, low P, and combined stress-mediated Na+/K+, reactive oxygen species (ROS), malondialdehyde (MDA), lipoxygenase (LOX) activity, and methylglyoxal (MG) in both genotypes. Individually, salinity and low P increased superoxide dismutase (SOD) activity in both genotypes, but combined stress decreased the activity. Peroxidase (POD) activity increased in all stress treatments. Interestingly, Tre application enhanced the SOD activity in all the stress treatments but inhibited the POD activity. Both catalase (CAT) and glutathione peroxidase (GPX) activity were increased by saline and low P stress while the activities inhibited in combined stress. Similar results were found for ascorbate peroxidase (APX), glutathione peroxidase (GR), and dehydroascorbate reductase (DHAR) activities in both genotypes. However, monodehydroascorbate reductase (MDHAR) activity was inhibited in all the stresses. Interestingly, Tre enhanced CAT, APX, GPX, GR, MDHAR, and DHAR activities suggesting the amelioration of ROS scavenging in maize under all the stresses. Conversely, increased glyoxalase activities in saline and low P stress in BHM-9 suggested better MG detoxification system because of the down-regulation of glyoxalase-I (Gly-I) activity in BHM-7 in those stresses. Tre also increased the glyoxalase activities in both genotypes under all the stresses. Tre improved the growth in maize seedlings by decreasing Na+/K+, ROS, MDA, and MG through regulating antioxidant and glyoxalase systems.
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Ali, Amjad, Li Hongbin, Li Rong, Sara Zahid, Nasir Uddin, Anis Safir, Tariq Masood, and Waqas Safir. "PHYSIOLOGICAL AND BIOCHEMICAL ANALYSIS OF ASA-GSH ANTIOXIDANT SYSTEM OF SEA-ISLAND COTTON IN RESPONSE TO VERTICILLIUM DAHLIAE." JOURNAL OF MICROBIOLOGY AND MOLECULAR GENETICS 3, no. 3 (December 31, 2022): 31–55. http://dx.doi.org/10.52700/jmmg.v3i3.60.
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Sea-Island cotton (Gossypium barbadense) is a high-quality long-fiber cotton species and is mainly planted in southern region of Xinjiang. The primary disease is Verticillium wilt, which is caused by Verticillium dahlia affecting G. barbadense growth and development. That leads to reduction in quality and yield of the fibers and thus to the huge economic loss. AsA-GSH antioxidant system has been extensively studied and is seen as having a crucial function in plant’s response to biotic and abiotic stresses. The goal of this study is to look into the resistant mechanism of AsA-GSH antioxidant system in Gossypiumbarbadense in response to V. dahliae. The two varieties, wilt-susceptible XH17 and wilt-resistant XH24, were incubated by V991 strain of V. dahliae and the treated leaves were collected for the physiological and biochemical analysis of AsA-GSH antioxidant system. The leaves were collected at day 0, 2, 6 and 9 after fungal inoculation and the functions of related enzymes of AsA-GSH antioxidant system including Superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione re-oxidase (GR), as well as the physiological indexes of malondialdehyde (MDA) and proline were measured. The mRNA and protein expression levels of the genes of APX, dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), SOD, CAT, and GR, that constitute AsA-GSH antioxidant system, were analyzed by the transcriptomic and proteomic data. The enzyme activities of CAT, SOD, GR, and APX were found to be increased significantly after V. dahliae treatment in both XH24 and XH17. Interestingly, SOD and APX activities maintained at relative high values in wilt-resistant XH24 but a decrease in values was observed during the late stage of V. dahliae treatment in case of wilt-susceptible XH17. High proline accumulation and low MDA content were observed in wilt-resistant XH24. The results of AsA-GSH antioxidant system genes shows that four APX members of GbAPX1A, GbAPX1D, GbAPX10D, and GbAPX12A, one DHAR member GbDHAR2D, four MDHAR members of GbMDHAR1A, GbMDHAR1D, GbMDHAR3A, and GbMDHAR3D, two GR members of GbGR2A and GbGR2D, two CAT members of GbCAT1A and GbCAT1D, and six SOD members of GbCSD4A, GbCSD5A, GbCSD4D, GbCSD5D, GbMSD1D and GbMSD1A were all expressed induced accumulations significantly after V. dahliae treatment, implying their important potential functions for G. barbadense to resist V. dahliae. Generally, the protein expression and mRNA expression indicated a similar profile, while some unique expressions of these AsA-GSH antioxidant system genes were also been discovered. There were ten APX members of GbAPX1D, GbAPX2A, GbAPX2D, GbAPX3A, GbAPX3D, GbAPX6A, GbAPX6D, GbAPX8A, GbAPX12A, and GbAPX3D; all six DHAR members with the exception of GbDHAR2D; three GR members locating in A sub-genome containing GbGR 1A, GbGR 2A, and GbGR 3A; six MDAHR members including GbMDAHR1A, GbMDAHR1D, GbMDAHR3A, GbMDAHR3D, GbMDAHR4A, and GbMDAHR4D; two CAT members of GbCAT1A and GbCAT4D; as well as eight SOD members of GbCSD1A, GbCSD4A, GbCSD4D, GbCSD2A, GbMSD2D, GbMSD2D, GbMSD1A and GbMSD1D, to indicate steady high expressions. These results indicated that there exist some close link and consistency between the mRNA and protein expressions, and that the preferentially expressed proteins of AsA-GSH antioxidant system might perform important functions as enzymes to catalyze the oxidation/reduction reactions and thus to maintain the redox balance and integrity of the cells in the process of G. barbadense plants to resist V. dahliae.
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Moussa, H. "Effect of gamma radiation on antioxidant enzymes and G 6 PDH activities in Vicia faba plants." Acta Agronomica Hungarica 57, no. 1 (March 1, 2009): 79–86. http://dx.doi.org/10.1556/aagr.57.2009.1.9.
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The effect of gamma irradiation on Vicia faba L. plants was investigated by exposing dry seeds to doses ranging from 0 to 100 Gray (Gy) and studying the activities and isozyme patterns of the key enzymes involved in oxidative stress defence, such as superoxide dismutases (SOD, EC 1.15.1.1), catalases (CAT, EC 1.11.1.6), peroxidases (POX, EC 1.11.1.7), ascorbate peroxidases (APOX, EC 1.11.1.11), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) and glutathione reductase (GR, EC 1.6.4.2), as well as the activity of an enzyme involved in a specific intermediary metabolic pathway, glucose-6-phosphate dehydrogenase (G 6 PDH, EC 1.1.1.49). The H 2 O 2 contents of faba bean leaves were also measured. None of the γ-irradiation doses used (0–100 Gy) had any effect on the activity of MDHAR, but they increased the enzyme activities of GR, APOX, SOD and G 6 PDH. Gamma rays at 20 Gy decreased the H 2 O 2 content, but the 100 Gy dose significantly increased the H 2 O 2 content compared with the non-irradiated plants. The results implied that the isozymes of SOD, CAT and POX present in faba bean cells growing in the presence of 0–15 Gy γ-irradiation are required to remove the reactive oxygen species (ROS) produced during normal, physiological processes. When the dose of γ-irradiation is ≥20 Gy, the level of ROS (produced indirectly by γ-irradiation) becomes too high to be dealt with by the existing antioxidant isozymes. The present research shows for the first time that the switch between the physiological oxidative response and a stress-related one occurs within a very narrow range of stress factor intensities, i.e. γ-irradiation doses. In the present study, this change took place between 15 and 20 Gy. Further investigations, using molecular biology techniques will be needed to determine the mechanisms involved in enzyme induction under ionizing conditions in order to evaluate changes in the gametic genomes at two possible levels: (i) the structural level, for studying mutations occurring in the DNA, and (ii) the functional level, by studying differential genetic expression between irradiated and non-irradiated plants.
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Hernández, Jose A., Ana Belén Aguilar, Bruno Portillo, Elvira López-Gómez, Jorge Mataix Beneyto, and Manuel F. García-Legaz. "The effect of calcium on the antioxidant enzymes from salt-treated loquat and anger plants." Functional Plant Biology 30, no. 11 (2003): 1127. http://dx.doi.org/10.1071/fp03098.
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Salt treatment (50 mM NaCl) reduced plant growth of loquat (Eribotria japonica Lindl.) (by up to 40%) but not that of anger (Cydonia oblonga Mill.). Salt stress induced a strong leaf Na+ accumulation in both species. However, the observed increase in leaf Cl– level was higher in loquat (13-fold) than in anger plants (3.8-fold). Addition of Ca2+ (25 mM) significantly reduced Na+ and Cl– concentrations in both salt-treated species. In anger leaves, calcium addition to the nutrient media did not change the leaf calcium contents in salt-treated or untreated plants, this value being lower in salt-treated plants. However, in loquat plants, an increase in leaf Ca2+ was observed after the calcium addition. Surprisingly, an increase in Ca2+ concentration was also observed in salt-treated loquat plants. In general, anger plants had higher constitutive antioxidant enzyme levels in both control and salt-treated plants. Salt stress did not change antioxidant enzyme levels in loquat plants. A similar effect was observed in anger plants, but in this case a 2-fold induction of monodehydroascorbate reductase (MDHAR) activity was observed.In both species, salinity produced an oxidative stress, indicated by an increase in lipid peroxidation, this value being much higher in loquat (83%) than in anger (40%) plants. In salt-treated plants, Ca2+ addition provided some protection to the membranes, because the increases observed in thiobarbituric-acid-reactive substances (TBARS) were not significant.In contrast, in control plants Ca2+ treatments increased glutathione reductase (GR) and decreased catalase activity in anger, but increased MDHAR, dehydroascorbate reductase (DHAR), GR and superoxide dismutase (SOD) in loquat plants. In salt-treated plants, Ca2+ additions decreased catalase (CAT) and ascorbate peroxidase (APX) for anger and raised DHAR, GR and SOD for loquat. However, the mechanism by which Ca2+ regulates antioxidant enzymes remains to be determined.These results suggest that anger plants have a higher capacity to scavenge AOS, both under saline and non-saline conditions. Accordingly, and related to the smaller Cl– increase observed, anger plants are more salt-tolerant, at least partly owing to the higher antioxidant enzyme levels observed.
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Singh, P., V. K. Zhawar, and P. P. S. Pannu. "Effect of gamma-aminobutyric acid on resistance against stripe rust (caused by Puccinia striiformis f. sp. tritici) in wheat cultivars." Journal of Environmental Biology 44, no. 2 (March 13, 2023): 159–66. http://dx.doi.org/10.22438/jeb/44/2/mrn-5027.
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Aim: The present study was undertaken to screen wheat cultivars for resistance against stripe rust and the improvement of resistance by exogenous gamma-aminobutyric acid (GABA) under field conditions and studying two contrasting cultivars for antioxidant related defense activities at 1, 2 and 4 d of GABA, Puccinia striiformis f. sp. tritici (Pst) and GABA+Pst treatments given to one-month-old seedlings. Methodology: Wheat cultivars (PBW723, PBW725, PBW677, PBW550, PBW343, PBW621, HD2967) were grown and exposed to Puccinia striiformis f. sp. tritici (Pst) and GABA+Pst in fields and studied for yield parameters. Subsequently, two cultivars found varying in resistance (PBW725 and HD2967) were analyzed for antioxidant enzymes in leaves and roots at 1, 2, and 4 day of GABA, Pst, and GABA+Pst and water as control given to 30 days old seedlings in the greenhouse. Results: Field analysis found that the most resistant cultivar PBW725 reduced vegetative growth but not yield compared to other resistant cultivars (PBW723 and PBW677) under Pst and improved both growth and yield under GABA+Pst. GABA+Pst improved yield parameters in other cultivars also. In defense analysis, superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione-S-transferase (GST) increased in the leaves of PBW725 while only APX increased in HD2967 at 1 d of Pst. In roots also, SOD and GST increased 2-fold in PBW725 while only GST increased 1.3-fold in HD2967 at 1 d of Pst. There was persistence of catalase (CAT), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR) during Pst in the leaves of PBW 725 while CAT decreased at 4 d in HD2967. In roots also, CAT and MDHAR increased at 4 days of Pstin PBW725 while DHAR decreased in HD2967. Under GABA, cultivar differences were not significant. GABA+Pst improved deficient antioxidant enzymes in HD2967. Interpretation: Energy conservation and timely regulation of antioxidant enzymes during infection was utilized by PBW725 against stripe rust. GABA deficiency can be a reason for poor regulation of antioxidants in HD2967 under Pst. GABA application improved resistance against stripe rust in wheat. Key words: Antioxidant, Ascorbate, Gamma-aminobutyric acid, Glutathione, Stripe rust, Triticum aestivum
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محسنی, آزاده, قربانعلی نعمت زاده, علی دهستانی کلاگر, بهزاد شاهین کلیبر, and الهام سلیمانی. "Cloning and Bioinformatics Analysis of MDHAR Gene from Aeluropus Littoralis and Over-Expression Analysis in Nicotina Tabacum." Journal of Crop Breeding 8, no. 17 (April 1, 2016): 230–19. http://dx.doi.org/10.18869/acadpub.jcb.8.17.230.
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Hu, Linli, Yutong Li, Yue Wu, Jian Lv, Mohammed Mujitaba Dawuda, Zhongqi Tang, Weibiao Liao, Alejandro Calderón-Urrea, Jianming Xie, and Jihua Yu. "Nitric Oxide Is Involved in the Regulation of the Ascorbate–Glutathione Cycle Induced by the Appropriate Ammonium: Nitrate to Mitigate Low Light Stress in Brassica pekinensis." Plants 8, no. 11 (November 11, 2019): 489. http://dx.doi.org/10.3390/plants8110489.
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Low light intensity is common in northern China due to fog or haze, and causes stress for crop plants. To solve the problem of low light intensity stress on the growth and development of vegetable crops in China, new cropping strategies must be developed. We previously showed that an appropriate ratio of ammonium and nitrate (NH4+:NO3−) can alleviate the effect of low light stress on plants, although it is not clear what mechanism is involved in this alleviation. We propose the hypothesis that an appropriate ammonium/nitrate ratio (10:90) can induce NO synthesis to regulate the AsA-GSH cycle in mini Chinese cabbage seedlings under low light intensity. To test the hypothesis, we conducted a series of hydroponic experiments. The results indicated that, under low light intensity conditions, appropriate NH4+:NO3− (N, NH4+:NO3− = 10:90) decreased the contents of malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion (O2−) in leaves compared with nitrate treatment. Exogenous nitric oxide (SNP) had the same effects on MDA, H2O2, and O2−. However, with the addition of a NO scavenger (hemoglobin, Hb) and NO inhibitors (N-nitro-l-arginine methyl ester, L-NAME), NaN3 (NR inhibitor) significantly increased the contents of MDA, H2O2, and O2-. The application of N solution enhanced the AsA-GSH cycle by increasing the activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and ascorbate oxidase (AAO), compared with control (NH4+:NO3− = 0:100). Meanwhile, exogenous SNP significantly increased the above indicators. All these effects of N on AsA-GSH cycle were inhibited by the addition of Hb, L-NAME and NaN3 in N solution. The results also revealed that the N and SNP treatments upregulated the relative expression level of GR, MDHAR1, APXT, DHAR2, and AAO gene in mini Chinese cabbage leaves under low light stress. These results demonstrated that the appropriate NH4+:NO3− (10:90) induced NO synthesis which regulates the AsA-GSH cycle in mini Chinese cabbage seedlings under low light stress.
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Zhao, Tian Hong, Jun Li Wang, Yan Wang, and Ying Cao. "Effects of Antioxidant Enzymes of Ascorbate-Glutathione Cycle in Soybean (Glycine Max) Leaves Exposed to Ozone." Advanced Materials Research 204-210 (February 2011): 672–77. http://dx.doi.org/10.4028/www.scientific.net/amr.204-210.672.
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Open-top chambers (OTCs) were used to investigate the mechanism of antioxidant enzymes to eliminate reactive oxygen species (ROS) of plants under troposphere O3stress. The results indicated that, compared to control, the O3concentration of 80±10 nL·L-1and 110±10 nL·L-1induced an increase on malondialdehyde (MDA) content and a decrease on superoxide anion (O2)production rate and hydrogen peroxide (H2O2) content during the whole growth stage. Simultaneity, it showed a trend of increasing in earlier stage and decreasing in later stage of the activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR), while the dehydroascorbate reductase (DHAR) activity was increased in earlier period, decreased in middle periods and then increased in later period compared to control, respectively. The results show that elevated O3concentration accelerates ROS metabolism rates, reduces the efficiency of antioxidant enzymes that can not tolerate oxidative damage caused by elevated O3concentration, which represents injured affects to soybean.
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Shin, Sun-Young, Il-Sup Kim, Young-Saeng Kim, Hyoshin Lee, and Ho-Sung Yoon. "Ectopic expression of Brassica rapa L. MDHAR increased tolerance to freezing stress by enhancing antioxidant systems of host plants." South African Journal of Botany 88 (September 2013): 388–400. http://dx.doi.org/10.1016/j.sajb.2013.08.015.
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Rajput, Vishnu D., Harish, Rupesh Kumar Singh, Krishan K. Verma, Lav Sharma, Francisco Roberto Quiroz-Figueroa, Mukesh Meena, et al. "Recent Developments in Enzymatic Antioxidant Defence Mechanism in Plants with Special Reference to Abiotic Stress." Biology 10, no. 4 (March 26, 2021): 267. http://dx.doi.org/10.3390/biology10040267.
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The stationary life of plants has led to the evolution of a complex gridded antioxidant defence system constituting numerous enzymatic components, playing a crucial role in overcoming various stress conditions. Mainly, these plant enzymes are superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferases (GST), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR), which work as part of the antioxidant defence system. These enzymes together form a complex set of mechanisms to minimise, buffer, and scavenge the reactive oxygen species (ROS) efficiently. The present review is aimed at articulating the current understanding of each of these enzymatic components, with special attention on the role of each enzyme in response to the various environmental, especially abiotic stresses, their molecular characterisation, and reaction mechanisms. The role of the enzymatic defence system for plant health and development, their significance, and cross-talk mechanisms are discussed in detail. Additionally, the application of antioxidant enzymes in developing stress-tolerant transgenic plants are also discussed.
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Zhang, Yong Bao. "Role of ASC-GSH Metabolism in Trifolium Repens L." Advanced Materials Research 343-344 (September 2011): 815–19. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.815.
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In order to elucidate the role of ascorbate-glutathione (ASC-GSH) cycle to drought stress, the activities of antioxidant enzymes and the levels of molecules involved in the ASC-GSH metabolism were studied in Trifolium repens seedlings subjected to polyethylene glycol (PEG)-induced water deficit. Compared to the control, the contents of ascorbate (ASC), dehydroascorbate (DHA) and glutathione disulfide (GSSG) increased in PEG-treated seedlings, whereas the glutathione (GSH) content kept constant during the drought period. Further more, the values of ASC/DHA and GSH/GSSG ratios decreased in the presence of PEG. Except for that of monodehydroascorbate reductase (MDHAR), the activities of ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) were upregulated during water deficit, and the increases of APX and DHAR activities were much higher than that of GR activity. These data indicated that fluctuations of the ASC-GSH metabolism resulted from PEG may have a positive effect on drought stress mitigation in T. repens, and the antioxidant protection in ASC-GSH cycle can be attributed mainly to ASC, APX and DHAR.
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Hou, Yuanyuan, Ziying Li, Yonghua Zheng, and Peng Jin. "Effects of CaCl2 Treatment Alleviates Chilling Injury of Loquat Fruit (Eribotrya japonica) by Modulating ROS Homeostasis." Foods 10, no. 7 (July 19, 2021): 1662. http://dx.doi.org/10.3390/foods10071662.
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The effects of calcium chloride (CaCl2) treatment on chilling injury (CI), reactive oxygen species (ROS) metabolism, and ascorbate-glutathione (AsA-GSH) cycle in loquat fruit at 1 °C storage for 35 d were investigated. The results indicated that CaCl2 treatment remarkably suppressed the increase in browning index and firmness as well as the decrease in extractable juice rate. CaCl2 treatment also decreased the production of superoxide radical (O2•−), hydrogen peroxide (H2O2) content, but increased the 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (OH•) scavenging ability, the activities of superoxide dismutase (SOD), catalase (CAT), and their gene expressions. Moreover, compared to the control loquat fruit, CaCl2-treated fruit maintained higher contents of AsA, GSH, higher levels of activities of ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR) and expressions of EjAPX, EjGR, EjMDHAR, and EjDHAR, but exhibited lower glutathione disulfide (GSSG) content. These results suggested that CaCl2 treatment alleviated CI in loquat fruit through enhancing antioxidant enzymes activities and AsA-GSH cycle system to quench ROS.
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Wen, Yuan, Lingyan Zha, and Wenke Liu. "Dynamic Responses of Ascorbate Pool and Metabolism in Lettuce to Light Intensity at Night Time under Continuous Light Provided by Red and Blue LEDs." Plants 10, no. 2 (January 23, 2021): 214. http://dx.doi.org/10.3390/plants10020214.
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To understand the dynamic changes of hydroponic lettuce growth, ascorbate (AsA) pool and metabolism under two different dark period light intensities (LL, 20 μmol·m−2·s−1; CL, 200 μmol·m−2·s−1) of continuous light and normal light (NL, 0 μmol·m−2·s−1) provided by red (R) and blue (B) LEDs, the chlorophyll fluorescence parameters, ascorbate pool size, AsA metabolism-related enzyme activities, and H2O2 contents of lettuce were measured at 0, 8, 16, 24, 32, 40, 48, 56, 64, and 72 h after light treatment and the lettuce growth parameters were measured on the 9th day after light treatment. The results showed that compared with the NL, CL treatment for 9 days significantly increased the biomass, dry matter content, and specific leaf weight of lettuce, but had no significant effect on the leaf area and root-to-shoot ratio; LL had no significant effect on lettuce biomass, but it would reduce the root-shoot ratio. Compared with the NL, the AsA content of CL increased significantly within 8 h after light treatment (at the end of first dark period), and then maintained at a relatively stable level with a slight increase; there was no significant difference in AsA contents between NL and LL showing the same circadian rhythm characteristics. Overall, the activities of L-galactono-1,4-lactone dehydrogenase (GalLDH), ascorbate peroxidase(APX), monodehydroascorbate reductase (MDHAR), and glutathione reductase (GR) under CL were the highest among the three treatments, and the differences with the other two treatments reached significant levels at several time points; there was almost no significant difference in the activities of GalLDH, APX, MDHAR, and GR between NL and LL; there was no significant difference in the activities of dehydroascorbate reductase (DHAR) under different treatments. Compared with the NL, CL caused a sharp decrease of PSⅡ maximal photochemical efficiency (Fv/Fm) in lettuce within 0–8 h after treatment, which then stabilized at a relatively stable level; the Fv/Fm value under the LL was almost the same as the NL. Except for 32 h, the H2O2 content of lettuce under CL was the highest among the three treatments during the entire experimental period, and was significantly higher than that of NL at several time points; the H2O2 content of LL was almost the same as NL. In summary, lettuce biomass, AsA contents, AsA metabolism-related enzyme activities, chlorophyll fluorescence parameters, and H2O2 contents were regulated by the dark period light intensities of continuous light rather than continuous light signals.
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Villani, Alessandra, Franca Tommasi, and Costantino Paciolla. "The Arbuscular Mycorrhizal Fungus Glomus viscosum Improves the Tolerance to Verticillium Wilt in Artichoke by Modulating the Antioxidant Defense Systems." Cells 10, no. 8 (July 30, 2021): 1944. http://dx.doi.org/10.3390/cells10081944.
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Verticillium wilt, caused by the fungal pathogen Verticillium dahliae, is the most severe disease that threatens artichoke (Cynara scolymus L.) plants. Arbuscular mycorrhizal fungi (AMF) may represent a useful biological control strategy against this pathogen attack, replacing chemical compounds that, up to now, have been not very effective. In this study, we evaluated the effect of the AMF Glomus viscosum Nicolson in enhancing the plant tolerance towards the pathogen V. dahliae. The role of the ascorbate-glutathione (ASC-GSH) cycle and other antioxidant systems involved in the complex network of the pathogen-fungi-plant interaction have been investigated. The results obtained showed that the AMF G. viscosum is able to enhance the defense antioxidant systems in artichoke plants affected by V. dahliae, alleviating the oxidative stress symptoms. AMF-inoculated plants exhibited significant increases in ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and superoxide dismutase (SOD) activities, a higher content of ascorbate (ASC) and glutathione (GSH), and a decrease in the levels of lipid peroxidation and hydrogen peroxide (H2O2). Hence, G. viscosum may represent an effective strategy for mitigating V. dahliae pathogenicity in artichokes, enhancing the plant defense systems, and improving the nutritional values and benefit to human health.
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Li, Jinna, Bing Yu, Chunquan Ma, Hongli Li, Desheng Jiang, Jingdong Nan, Meng Xu, et al. "Functional Characterization of Sugar Beet M14 Antioxidant Enzymes in Plant Salt Stress Tolerance." Antioxidants 12, no. 1 (December 27, 2022): 57. http://dx.doi.org/10.3390/antiox12010057.
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Salt stress can cause cellular dehydration, which induces oxidative stress by increasing the production of reactive oxygen species (ROS) in plants. They may play signaling roles and cause structural damages to the cells. To overcome the negative impacts, the plant ROS scavenging system plays a vital role in maintaining the cellular redox homeostasis. The special sugar beet apomictic monosomic additional M14 line (BvM14) showed strong salt stress tolerance. Comparative proteomics revealed that six antioxidant enzymes (glycolate oxidase (GOX), peroxiredoxin (PrxR), thioredoxin (Trx), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase3 (DHAR3)) in BvM14 were responsive to salt stress. In this work, the full-length cDNAs of genes encoding these enzymes in the redox system were cloned from the BvM14. Ectopic expression of the six genes reduced the oxidative damage of transgenic plants by regulating the contents of hydrogen peroxide (H2O2), malondialdehyde (MDA), ascorbic acid (AsA), and glutathione (GSH), and thus enhanced the tolerance of transgenic plants to salt stress. This work has charecterized the roles that the antioxidant enzymes play in the BvM14 response to salt stress and provided useful genetic resources for engineering and marker-based breeding of crops that are sensitive to salt stress.
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Sahoo, Ansuman, and Supriya Tiwari. "Antioxidants and Antioxidative Enzymes as Potential Biomarkers for Assessing Stress in Plants." INTERNATIONAL JOURNAL OF PLANT AND ENVIRONMENT 8, no. 02 (November 7, 2022): 95–105. http://dx.doi.org/10.18811/ijpen.v8i02.01.
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Reactive oxygen species (ROS) are an inevitable part of normal cellular metabolism in almost every known living organism. But theexcess accumulation of these radicals disturbs cellular homeostasis which can be harmful to the plant. Unlike animals who can migratethemselves away from the stress conditions, plants that are sedentary in nature have developed certain defence mechanisms to copewith the same. These mechanisms include a plethora of enzymatic and non-enzymatic antioxidants that help in scavenging free radicals.The enzymatic antioxidants include superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), guaiacol peroxidase (GPX),ascorbate peroxidase (APX), glutathione-s-transferase, monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR),and the non-enzymatic antioxidants include ascorbic acid (ASA), glutathione (GSH), tocopherols, carotenoids, etc. All these antioxidantshelp in maintaining the balance between ROS generation and scavenging by keeping their concentration below the threshold level.Numerous earlier studies have reported that only certain enzymatic antioxidants have shown increased activity in response to particularstress and likely these enzymes can be utilized as biomarkers against a multitude of biotic and abiotic stresses. In this review, we havediscussed certain enzymatic and a few non-enzymatic antioxidants which can be used for assessing stress in plants.
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Anisimova, O. K., A. V. Shchennikova, E. Z. Kochieva, and M. A. Filyushin. "Identification of Monodehydroascorbate Reductase (MDHAR) Genes in Garlic (Allium sativum L.) and Their Role in the Response to Fusarium proliferatum Infection." Russian Journal of Genetics 58, no. 7 (July 2022): 773–82. http://dx.doi.org/10.1134/s1022795422070031.
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Wang, Mingquan, Shichen Gong, Lixin Fu, Guanghui Hu, Guoliang Li, Shaoxin Hu, and Jianfei Yang. "The Involvement of Antioxidant Enzyme System, Nitrogen Metabolism and Osmoregulatory Substances in Alleviating Salt Stress in Inbred Maize Lines and Hormone Regulation Mechanisms." Plants 11, no. 12 (June 10, 2022): 1547. http://dx.doi.org/10.3390/plants11121547.
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Salt stress inhibited the growth of maize. B46 and NC236 were chosen as materials and NaCl concentrations (0, 55, 110, 165, and 220 mmol L−1) were set. We found the activities of SOD, POD, CAT, APX, GR, MDHAR, and DHAR decreased under NaCl stress. Compared with NC236, the contents of AsA and GSH, AsA/DHA and GSH/GSSG of B46 decreased. The content of O2−, H2O2, MDA, and EL of B46 increased. The contents of NO3− and NO2− decreased, while the content of NH4+ increased under high NaCl concentration. The activities of NR and NiR decreased, while the activities of GS and GOGAT increased first and then decreased. For B46 and NC236, the maximum of NADH-GDH and NAD-GDH appeared at 165 and 110 mmol L−1 NaCl concentration, respectively. Compared with B46, and the GOT and GPT activities of NC236 increased first and then decreased. With the increase of NaCl concentration, the contents of proline, soluble protein, and soluble sugar were increased. The Na+ content of B46 and NC236 increased, and the K+ content and K+/Na+ decreased. Compared with NC236, B46 had higher IAA content in leaf, higher Z + ZR content in leaf and root, and lower ABA content in leaf and root.
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Xu, Yanmei, Zhijun Cai, Liangjie Ba, Yonghua Qin, Xinguo Su, Donglan Luo, Wei Shan, et al. "Maintenance of Postharvest Quality and Reactive Oxygen Species Homeostasis of Pitaya Fruit by Essential Oil p-Anisaldehyde Treatment." Foods 10, no. 10 (October 13, 2021): 2434. http://dx.doi.org/10.3390/foods10102434.
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The performance of p-Anisaldehyde (PAA) for preserving pitaya fruit quality and the underpinning regulatory mechanism were investigated in this study. Results showed that PAA treatment significantly reduced fruit decay, weight loss and loss of firmness, and maintained higher content of total soluble solids, betacyanins, betaxanthins, total phenolics and flavonoids in postharvest pitaya fruits. Compared with control, the increase in hydrogen peroxide (H2O2) content and superoxide anion (O2•−) production was inhibited in fruit treated with PAA. Meanwhile, PAA significantly improved the activity of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT). Moreover, PAA-treated pitaya fruit maintained higher ascorbic acid (AsA) and reduced-glutathione (GSH) content but lower dehydroascorbate (DHA) and oxidized glutathione (GSSG) content, thus sustaining higher ratio of AsA/DHA and GSH/GSSG. In addition, activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydrogenation ascorbic acid reductase (DHAR), as well as the expression of HpSOD, HpPOD, HpCAT, HpAPX, HpGR, HpDHAR and HpMDHAR, were enhanced after PAA treatment. The findings suggest that postharvest application of PAA may be a reliable method to control postharvest decay and preserve quality of harvested pitaya fruit by enhancing the antioxidant potential of the AsA-GSH cycle and activating an antioxidant defense system to alleviate reactive oxygen species (ROS) accumulation.
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Hasanuzzaman, Mirza, Md Mahabub Alam, Anisur Rahman, Md Hasanuzzaman, Kamrun Nahar, and Masayuki Fujita. "Exogenous Proline and Glycine Betaine Mediated Upregulation of Antioxidant Defense and Glyoxalase Systems Provides Better Protection against Salt-Induced Oxidative Stress in Two Rice (Oryza sativaL.) Varieties." BioMed Research International 2014 (2014): 1–17. http://dx.doi.org/10.1155/2014/757219.
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The present study investigates the roles of exogenous proline (Pro, 5 mM) and glycine betaine (GB, 5 mM) in improving salt stress tolerance in salt sensitive (BRRI dhan49) and salt tolerant (BRRI dhan54) rice (Oryza sativaL.) varieties. Salt stresses (150 and 300 mM NaCl for 48 h) significantly reduced leaf relative water (RWC) and chlorophyll (chl) content and increased endogenous Pro and increased lipid peroxidation and H2O2levels. Ascorbate (AsA), glutathione (GSH) and GSH/GSSG, ascorbate peroxidae (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione peroxidase (GPX), catalase (CAT), and glyoxalase I (Gly I) activities were reduced in sensitive variety and these were increased in tolerant variety due to salt stress. The glyoxalase II (Gly II), glutathione S-transferase (GST), and superoxide dismutase (SOD) activities were increased in both cultivars by salt stress. Exogenous Pro and GB application with salt stress improved physiological parameters and reduced oxidative damage in both cultivars where BRRI dhan54 showed better tolerance. The result suggests that exogenous application of Pro and GB increased rice seedlings’ tolerance to salt-induced oxidative damage by upregulating their antioxidant defense system where these protectants rendered better performance to BRRI dhan54 and Pro can be considered as better protectant than GB.
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Rahman, Anisur, Mohammad Golam Mostofa, Md Mahabub Alam, Kamrun Nahar, Mirza Hasanuzzaman, and Masayuki Fujita. "Calcium Mitigates Arsenic Toxicity in Rice Seedlings by Reducing Arsenic Uptake and Modulating the Antioxidant Defense and Glyoxalase Systems and Stress Markers." BioMed Research International 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/340812.
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The effect of exogenous calcium (Ca) on hydroponically grown rice seedlings was studied under arsenic (As) stress by investigating the antioxidant and glyoxalase systems. Fourteen-day-old rice (Oryza sativaL. cv. BRRI dhan29) seedlings were exposed to 0.5 and 1 mM Na2HAsO4alone and in combination with 10 mM CaCl2(Ca) for 5 days. Both levels of As caused growth inhibition, chlorosis, reduced leaf RWC, and increased As accumulation in the rice seedlings. Both doses of As in growth medium induced oxidative stress through overproduction of reactive oxygen species (ROS) by disrupting the antioxidant defense and glyoxalase systems. Exogenous application of Ca along with both levels of As significantly decreased As accumulation and restored plant growth and water loss. Calcium supplementation in the As-exposed rice seedlings reduced ROS production, increased ascorbate (AsA) content, and increased the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), catalase (CAT), glutathione peroxidase (GPX), superoxide dismutase (SOD), and the glyoxalase I (Gly I) and glyoxalase II (Gly II) enzymes compared with seedlings exposed to As only. These results suggest that Ca supplementation improves rice seedlings tolerance to As-induced oxidative stress by reducing As uptake, enhancing their antioxidant defense and glyoxalase systems, and also improving growth and physiological condition.
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Amer, Hanaa E. A., Hamada AbdElgawad, Mahmoud M. Y. Madany, Ahmed M. A. Khalil, and Ahmed M. Saleh. "Soil Contamination with Europium Induces Reduced Oxidative Damage in Hordeum vulgare Grown in a CO2-Enriched Environment." Plants 12, no. 17 (September 2, 2023): 3159. http://dx.doi.org/10.3390/plants12173159.
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The extensive and uncontrolled utilization of rare earth elements, like europium (Eu), could lead to their accumulation in soils and biota. Herein, we investigated the impact of Eu on the growth, photosynthesis, and redox homeostasis in barley and how that could be affected by the future CO2 climate (eCO2). The plants were exposed to 1.09 mmol Eu3+/kg soil under either ambient CO2 (420 ppm, aCO2) or eCO2 (620 ppm). The soil application of Eu induced its accumulation in the plant shoots and caused significant reductions in biomass- and photosynthesis-related parameters, i.e., chlorophyll content, photochemical efficiency of PSII, Rubisco activity, and photosynthesis rate. Further, Eu induced oxidative stress as indicated by higher levels of H2O2 and lipid peroxidation products, and lower ASC/DHA and GSH/GSSG ratios. Interestingly, the co-application of eCO2 significantly reduced the accumulation of Eu in plant tissues. Elevated CO2 reduced the Eu-induced oxidative damage by supporting the antioxidant defense mechanisms, i.e., ROS-scavenging molecules (carotenoids, flavonoids, and polyphenols), enzymes (CAT and peroxidases), and ASC-GSH recycling enzymes (MDHAR and GR). Further, eCO2 improved the metal detoxification capacity by upregulating GST activity. Overall, these results provide the first comprehensive report for Eu-induced oxidative phytotoxicity and how this could be mitigated by eCO2.
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Huang, Fenglan, Yaxuan Jiang, Subin Zhang, Shuo Liu, Tong-Ju Eh, Fanjuan Meng, and Pei Lei. "A Comparative Analysis on Morphological and Physiological Characteristics between Castor Varieties (Ricinus communis L.) under Salt Stress." Sustainability 14, no. 16 (August 13, 2022): 10032. http://dx.doi.org/10.3390/su141610032.
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Salt stress is one of the main abiotic factors affecting castor yield. Wild castor resources can provide important insights for cultivated castor breeding. However, little is known about how wild castor responds or adapts to salt stress. To understand the physiological mechanisms for salt tolerance in castor, the morphological and physiological responses of two varieties, wild and cultivated castor, with contrasted salt tolerance were characterized under salt stress. Seedlings were exposed to 0, 50, and 100 mM NaCl. The results showed that salt application significantly inhibited the increase in chlorophyll content and relative water content of cultivated castor. The degree of electrolyte leakage of wild castor under salt stress was significantly less than that of cultivated castor. In addition, the WT showed a lower content of reactive oxygen species (ROS) under the salt stress compared to CT. The activities of antioxidant enzymes like SOD, APX, GR, and MDHAR in the leaves of WT showed higher accumulation compared to those of CT under salt stress. The ratio of ASA/DHA and GSH/GSSG in leaves of WT showed a distinct increase compared to CT. In summary, our results revealed the salt stress resistance characteristics of wild castor. Wild castor also has the potential to be used as parental material in a breeding program. These results will be valuable for salt resistance breeding of cultivated castor.
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Wang, Huiping, Zeci Liu, Jing Li, Shilei Luo, Jing Zhang, and Jianming Xie. "Hydrogen Sulfide Interacts with 5-Aminolevulinic Acid to Enhance the Antioxidant Capacity of Pepper (Capsicum annuum L.) Seedlings under Chilling Stress." Agronomy 12, no. 3 (February 25, 2022): 572. http://dx.doi.org/10.3390/agronomy12030572.
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5-Aminolevulinic acid (ALA) is the precursor of tetrapyrrole synthesis, and hydrogen sulfide (H2S) is a gas signal molecule. Studies have shown that exogenous ALA and H2S can alleviate abiotic stress. This study evaluated the roles of ALA and H2S and their interactions in regulating antioxidant activity in pepper seedlings under chilling stress. Chilling stress significantly inhibited the growth of pepper seedlings and increased the amounts of hydrogen peroxide (H2O2), superoxide anion (O2•−), and malondialdehyde (MDA). ALA and/or H2S increased the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Moreover, ALA and/or H2S enhanced the ascorbate (AsA)-glutathione (GSH) cycle by increasing the contents of AsA and GSH, the ratio of AsA to dehydroascorbic acid and GSH to glutathione disulfide increased, and the activities of ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) also increased. At the transcriptional level, ALA and/or H2S upregulated the expressions of CaSOD, CaPOD, CaCAT, CaAPX, CaGR, CaDHAR, and CaMDHAR in seedlings under chilling stress. ALA and/or H2S also reduced the contents of H2O2, O2•− and MDA, eventually mitigating the inhibitory effects of chilling stress on pepper seedling growth. The combination of ALA and H2S had a better effect than ALA or H2S alone. Moreover, ALA and H2S interact to regulate the oxidative stress response of pepper seedlings under chilling stress.
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Bouzroud, Sarah, Karla Gasparini, Guojian Hu, Maria Antonia Machado Barbosa, Bruno Luan Rosa, Mouna Fahr, Najib Bendaou, et al. "Down Regulation and Loss of Auxin Response Factor 4 Function Using CRISPR/Cas9 Alters Plant Growth, Stomatal Function and Improves Tomato Tolerance to Salinity and Osmotic Stress." Genes 11, no. 3 (March 3, 2020): 272. http://dx.doi.org/10.3390/genes11030272.
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Auxin controls multiple aspects of plant growth and development. However, its role in stress responses remains poorly understood. Auxin acts on the transcriptional regulation of target genes, mainly through Auxin Response Factors (ARF). This study focuses on the involvement of SlARF4 in tomato tolerance to salinity and osmotic stress. Using a reverse genetic approach, we found that the antisense down-regulation of SlARF4 promotes root development and density, increases soluble sugars content and maintains chlorophyll content at high levels under stress conditions. Furthermore, ARF4-as displayed higher tolerance to salt and osmotic stress through reduced stomatal conductance coupled with increased leaf relative water content and Abscisic acid (ABA) content under normal and stressful conditions. This increase in ABA content was correlated with the activation of ABA biosynthesis genes and the repression of ABA catabolism genes. Cu/ZnSOD and mdhar genes were up-regulated in ARF4-as plants which can result in a better tolerance to salt and osmotic stress. A CRISPR/Cas9 induced SlARF4 mutant showed similar growth and stomatal responses as ARF4-as plants, which suggest that arf4-cr can tolerate salt and osmotic stresses. Our data support the involvement of ARF4 as a key factor in tomato tolerance to salt and osmotic stresses and confirm the use of CRISPR technology as an efficient tool for functional reverse genetics studies.