Response of antioxidative enzymes to arsenic-induced phytotoxicity in leaves of a medicinal daisy, Wedelia chinensis Merrill.
01 Jul 2013-Journal of natural science, biology, and medicine (Medknow Publications)-Vol. 4, Iss: 2, pp 383-388
TL;DR: Although hydrogen peroxide content increased, level of lipid peroxidation and magnitude of membrane damage was quite normal, leading to normal growth of plant under Astreatment, suggesting W.chinensis is tolerant of As-toxicity, and thus, can be grown in As-contaminated zones.
Abstract: Background: Wedelia chinensis Merrill (Asteraceae) is a medicinally important herb, grown abundantly in soils contaminated with heavy metals, including toxic metalloid arsenic (As). The leaves have immense significance in treatment of various ailments. Objective: The present study was undertaken to ascertain whether the edible/usable parts experience oxidative stress in the form of membrane damage during As exposure or not. Materials and Methods: Responses of seven antioxidant enzymes were studied in leaves under 20 mg/L of As treatment in pot experiment. Results: When compared to control, activities of superoxide dismutase, monodehydroascorbatereductase, dehydroascorbatereductase, glutathione reductase, and gluathione peroxidase had increased, while the catalase level reduced and ascorbate peroxidase activity changed non-significantly in As-treated seedlings. This suggested overall positive response of antioxidant enzymes to As-induced oxidative stress. Although hydrogen peroxide content increased, level of lipid peroxidation and magnitude of membrane damage was quite normal, leading to normal growth (dry weight of shoot) of plant under Astreatment. Conclusion: W.chinensis is tolerant of As-toxicity, and thus, can be grown in As-contaminated zones.
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TL;DR: A critical assessment of the recent research reports available on metal/metalloid-accrued modulation of reduced AsA pool, AsA/DHA redox couple and AsA-related major enzymes, and the cumulative significance of these antioxidant system components in plant metal/ Metalloid stress tolerance is presented.
Abstract: The enhanced generation of reactive oxygen species (ROS) under metal/metalloid stress is most common in plants, and the elevated ROS must be successfully metabolized in order to maintain plant growth, development, and productivity Ascorbate (AsA) is a highly abundant metabolite and a water-soluble antioxidant, which besides positively influencing various aspects in plants acts also as an enigmatic component of plant defense armory As a significant component of the ascorbate-glutathione (AsA-GSH) pathway, it performs multiple vital functions in plants including growth and development by either directly or indirectly metabolizing ROS and its products Enzymes such as monodehydroascorbate reductase (MDHAR, EC 1654) and dehydroascorbate reductase (DHAR, EC 1851) maintain the reduced form of AsA pool besides metabolically controlling the ratio of AsA with its oxidized form (dehydroascorbate, DHA) Ascorbate peroxidase (APX, EC 111111) utilizes the reduced AsA pool as the specific electron donor during ROS metabolism Thus, AsA, its redox couple (AsA/DHA), and related enzymes (MDHAR, DHAR, and APX) cumulatively form an AsA redox system to efficiently protect plants particularly against potential anomalies caused by ROS and its products Here we present a critical assessment of the recent research reports available on metal/metalloid-accrued modulation of reduced AsA pool, AsA/DHA redox couple and AsA-related major enzymes, and the cumulative significance of these antioxidant system components in plant metal/metalloid stress tolerance
131 citations
Cites background from "Response of antioxidative enzymes t..."
...Increased MDHAR and DHAR activities helpedWedelia chinensis seedlings to combat As-induced phytotoxicity, as both enzymes are responsible for the AsA reduction in the AsA-GSH cycle (Talukdar and Talukdar 2013)....
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TL;DR: Interestingly, As stress showed consistent decrease in phosphate content and expression of phosphate transporters under both high and low phosphate conditions in roots of BRRI 33, suggesting that limiting phosphate transport mainly mediated by OsPHO1;2 directs less As accumulation inBRRI 33.
99 citations
TL;DR: It is demonstrated that Arabidopsis thaliana AtACR2 gene is a potential candidate for genetic engineering of plants to develop new crop cultivars that can be grown on arsenic contaminated fields to reduce arsenic content of the soil and can become a source of food containing no arsenic or exhibiting substantially reduced amount of this metalloid.
67 citations
Cites background from "Response of antioxidative enzymes t..."
...When exposed to As causing electrolyte leakage the cellular membranes of plants become damaged (Singh et al., 2006; Talukdar, 2013; Talukdar and Talukdar, 2013) which is often accompanied by an increase in malondialdehyde, a product of lipid peroxidation, pointing to the role of oxidative stress in…...
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01 Jan 2016
TL;DR: The redox-dependent modification of sensitive signalling proteins is proposed as a key mode of redox signal transmission, which plays a key role in the adaptive response to the adverse environment.
Abstract: Plants are frequently exposed to different stressful factors, both of biotic or abiotic nature, which limit their growth and productivity. To survive under stress conditions, plants must activate stress-specific signalling pathways, which finally lead to morphological, physiological, and biochemical changes that allow to adapt to the adverse environment. Cellular redox homeostasis, determined by a complex interplay between pathways that produce and scavenge reactive oxygen species (ROS), plays a key role in the adaptive response. Each deviation in the cellular redox state, due to an imbalance of ROS production and/or scavenging, is indicative of environmental disturbance and works as a signal. Under stress conditions, different ROS are produced in many cell compartments. Plants have very proficient, versatile and flexible antioxidant machinery, which comprises enzymes and metabolites with distinct biochemical properties and distinct sub-cellular localization. The antioxidant systems play a key role in the control of redox homeostasis, determining either the extent or the specificity of ROS signals and the downstream redox-dependent responses. Redox signalling is responsive to a number of environmental cues, and the complex and dynamic pathways of redox regulation occur in different cell compartments. The redox-dependent modification of sensitive signalling proteins is proposed as a key mode of redox signal transmission. Each redox-dependent interaction is opportunely regulated by a restricted environment, whose change transfers the complex system of information and influences the plant response to external changes.
57 citations
TL;DR: Owing to its wide action spectrum, the arsenic resistant PGPB could provide a new insight into the remediation of arsenic contaminated soil and serve as an effective growth promoting bioinoculant for plants in metal stressed soil.
52 citations
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TL;DR: In this article, the catalytic activity of catalase has been investigated using ultraviolet (UV) spectrophotometry and Titrimetric methods, which is suitable for comparative studies for large series of measurements.
Abstract: Publisher Summary Catalase exerts a dual function: (1) decomposition of H 2 O 2 to give H 2 O and O 2 (catalytic activity) and (2) oxidation of H donors, for example, methanol, ethanol, formic acid, phenols, with the consumption of 1 mol of peroxide (peroxide activity) The kinetics of catalase does not obey the normal pattern Measurements of enzyme activity at substrate saturation or determination of the K s is therefore impossible In contrast to reactions proceeding at substrate saturation, the enzymic decomposition of H 2 O 2 is a first-order reaction, the rate of which is always proportional to the peroxide concentration present Consequently, to avoid a rapid decrease in the initial rate of the reaction, the assay must be carried out with relatively low concentrations of H 2 O 2 (about 001 M) This chapter discusses the catalytic activity of catalase The method of choice for biological material, however, is ultraviolet (UV) spectrophotometry Titrimetric methods are suitable for comparative studies For large series of measurements, there are either simple screening tests, which give a quick indication of the approximative catalase activity, or automated methods
20,238 citations
TL;DR: Key steps of the signal transduction pathway that senses ROIs in plants have been identified and raise several intriguing questions about the relationships between ROI signaling, ROI stress and the production and scavenging ofROIs in the different cellular compartments.
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"Response of antioxidative enzymes t..." refers background in this paper
...[21-24] Superoxide dismutase (SOD) constitutes the first line of defense by dismutating the superoxide radicals, a major ROS, but produces hydrogen peroxide (H2O2) as an end product....
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TL;DR: Observations confirm that the electron donor for the scavenging of hydrogen peroxide in chloroplasts is L-ascorbate and that the L-ASCorbate is regenerated from DHA by the system: photosystem I-*ferredoxin-*NADP^>glutathione and a preliminary characterization of the chloroplast peroxidase is given.
Abstract: Intact spinach chloroplasts scavenge hydrogen peroxide with a peroxidase that uses a photoreductant as the electron donor, but the activity of ruptured chloroplasts is very low [Nakano and Asada (1980) Plant & Cell Physiol. 21: 1295]. Ruptured spinach chloroplasts recovered their ability to photoreduce hydrogen peroxide with the concomitant evolution of oxygen after the addition of glutathione and dehydroascorbate (DHA). In ruptured chloroplasts, DHA was photoreduced to ascorbate and oxygen was evolved in the process in the presence of glutathione. DHA reductase (EC 1.8.5.1) and a peroxidase whose electron donor is specific to L-ascorbate are localized in chloroplast stroma. These observations confirm that the electron donor for the scavenging of hydrogen peroxide in chloroplasts is L-ascorbate and that the L-ascorbate is regenerated from DHA by the system: photosystem I-*ferredoxin-*NADP^>glutathione. A preliminary characterization of the chloroplast peroxidase is given.
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01 Jan 1956
5,524 citations
"Response of antioxidative enzymes t..." refers background in this paper
...[1,5] Compounds from W....
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...India is rich in diversity of medicinal plants,[1,2] and daisies (family Compositae or Asteraceae) with their peculiar fruit structure form an integral part of this diverse natural medicine....
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TL;DR: In this paper, a modified version of the TBARS method was proposed for assessing the presence of malondialdehyde (MDA) and other non-MDA compounds absorbing at 532 nm.
Abstract: The occurrence of malondialdehyde (MDA), a secondary end product of the oxidation of polyunsatu- rated fatty acids, is considered a useful index of general lipid peroxidation A common method for measuring MDA, referred to as the thiobarbituric acid-reactive- substances (TBARS) assay, is to react it with thiobar- bituric acid (TBA) and record the absorbance at 532 nm However, many plants contain interfering compounds that also absorb at 532 nm, leading to overestimation of MDA values Extracts of plant tissues including purple eggplant (Solanum melongena L) fruit, carrot (Daucus carota L) roots, and spinach (Spinacia oleracea L) leaves were assessed for the presence of MDA and other non-MDA compounds absorbing at 532 nm A method described herein corrects for these interferences by subtracting the absorbance at 532 nm of a solution containing plant extract incubated without TBA from an identical solution containing TBA The reliability and eAciency of this spectrophotometric method was assessed by altering the relative ratios of exogenous MDA additions and/or extracts of red cabbage (Brassica oleracea L) leaves containing inter- fering compounds and then measuring MDA recovery Reliability was also validated through high-performance liquid chromatography and high-performance liquid chromatography-mass spectrometry techniques Results indicated that over 90% of exogenously added MDA could be recovered through the improved protocol If there were no corrections for interfering compounds, MDA equivalents were overestimated by up to 965% Interfering compounds were not detected in vegetables such as lettuce (Lactuca sativa L) and spinach which had low or negligible concentrations of anthocyanidin derivatives Comparisons between the TBARS method presented here and two currently accepted protocols indicated that the new modified method exhibits greater accuracy for quantifying TBA-MDA levels in tissues containing anthocyanins and/or other interfering com- pounds This modified protocol represents a facile and rapid method for assessment of lipid peroxidation in virtually all plant species that contain interfering com- pounds
3,090 citations
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