Superoxide-Dismutase Deficient Mutants in Common Beans (Phaseolus vulgaris L.): Genetic Control, Differential Expressions of Isozymes, and Sensitivity to Arsenic
28 Aug 2013-BioMed Research International (Hindawi Publishing Corporation)-Vol. 2013, pp 782450-782450
TL;DR: Gene expressions using qRT PCR confirmed higher expressions of Cu/Zn SOD transcripts in both mutants and the absence of Fe SOD in sodPv 1 and Mn S OD in SodPv 2 and ROS-imaging study revealed overaccumulation of both superoxides and H2O2 in leaves of double mutant.
Abstract: Two common bean (Phaseolus vulgaris L.) mutants, sodPv 1 and sodPv 2, exhibiting foliar superoxide dismutase (SOD) activity of only 25% and 40% of their mother control (MC) cv. VL 63 were isolated in EMS-mutagenized (0.15%, 8 h) M2 progeny. Native-PAGE analysis revealed occurrence of Mn SOD, Fe SOD, Cu/Zn SOD I and Cu/Zn SOD II isozymes in MC, while Fe SOD, and Mn SOD were not formed in sodPv 1 and sodPv 2 leaves, respectively. In-gel activity of individual isozymes differed significantly among the parents. SOD deficiency is inherited as recessive mutations, controlled by two different nonallelic loci. Gene expressions using qRT PCR confirmed higher expressions of Cu/Zn SOD transcripts in both mutants and the absence of Fe SOD in sodPv 1 and Mn SOD in sodPv 2. In 50 μM arsenic, Cu/Zn SODs genes were further upregulated but other isoforms downregulated in the two mutants, maintaining SOD activity in its control level. In an F2 double mutants of sodPv 1 × sodPv 2, no Fe SOD, and Mn SOD expressions were detectable, while both Cu/Zn SODs are down-regulated and arsenic-induced leaf necrosis appeared. In contrast to both mutants, ROS-imaging study revealed overaccumulation of both superoxides and H2O2 in leaves of double mutant.
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TL;DR: Results revealed that major metabolic reshuffling is imminent in both up-stream and down-stream thiol cascade during low GSH-redox, and H2S may confer As-tolerance through stimulation of G SH-independent antioxidant defense and maintaining Cys-homeostasis in grass pea mutant.
Abstract: Coordinated response between cysteine (Cys) metabolisms as up-stream and GSH-dependent antioxidant defense as down-stream thiol cascade was investigated in two genotypes of hardy legume grass pea (Lathyrus sativus L.), namely a glutathione (GSH)-deficient mutant (gshL-1) and BioL-212 genotype under (a) 40 μM As (sodium arsenate) and (b) As +1 mM BSO (L-buthionine-sulfoximine) treatments. As-treatment alone induced biosynthesis of Cys, GSH, and phytochelatins but partially stimulated GSH-dependent antioxidant defense in the mutant. GSH S-transferase activity was elevated but activities of GSH-dependent ascorbate (AsA)-GSH cycle enzyme including GSH-reductase remained low in the As-exposed mutant. This resulted in As-induced partial growth inhibition of the mutant. At As + BSO, GSH-synthesis was totally inhibited, leading to significantly low GSH-redox pool and steep decline in GSH-dependent antioxidant capacity of both the genotypes. However, Cys-degradation pathway was induced in gshL-1 mutant, resulting in significant accumulation of endogenous H2S. This was accompanied with stimulation of AsA-dependent antioxidant defense and catalases and regulation of Cys-synthesis, preventing over-accumulation of H2O2 and free Cys, respectively. No As-induced oxidative damage and growth inhibition were observed in As + BSO-treated mutant. Contrastingly, failure to induce entire defense cascade under BSO resulted in onset of As-induced oxidative stress in BioL-212 genotype. Results revealed that major metabolic reshuffling is imminent in both up-stream and down-stream thiol cascade during low GSH-redox, and H2S may confer As-tolerance through stimulation of GSH-independent antioxidant defense and maintaining Cys-homeostasis in grass pea mutant.
5 citations
Cites methods from "Superoxide-Dismutase Deficient Muta..."
...…were orchestrated through elevated expressions of Cu/Zn SOD I, II and MnSOD transcripts and indicate predominant participation of cytosolic isoforms (Cu/Zn SODs) in maintaining SOD activity during As-exposures, as also reported earlier (Abercrombie et al. 2008; Talukdar and Talukdar 2013, 2014a)....
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...…were constructed by Primer Express TM V. 3.0 software (Applied Biosystems, USA) with the search of available sequence databases (http://www.ncbi.nlm.nih. gov/Report=GenBank) and reports on Lathyrus sativus, Phaseolus vulgaris, and lentils (Liao et al. 2012; Talukdar and Talukdar 2013, 2014a, b)....
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TL;DR: Results indicated vital role of glutathione in maintaining abnormal proliferations in plant organs, and its deficiency triggered phenotypic reversal through metabolic diversions of cysteine and concomitant cellular and metabolic modulations.
Abstract: A Lathyrus sativus L. mutant isolated in ethylmethane sulfonate-treated M2 progeny of mother variety BioL-212 and designated as rlfL-1 was characterized by inwardly rolled-leaf and stem and bud fasciations. The mutant exhibited karyomorphological peculiarities in both mitosis and meiosis with origin of aneuploidy. The mitosis was vigorous with high frequency of divisional cells and their quick turnover presumably steered cell proliferations. Significant transcriptional upregulations of cysteine and glutathione synthesis and concomitant stimulations of glutathione-mediated antioxidant defense helped rlfL-1 mutant to maintain balanced reactive oxygen species (ROS) metabolisms, as deduced by ROS-imaging study. Glutathione synthesis was shut down in buthionine sulfoximine- (BSO-) treated mother plant and mutant, and leaf-rolling and stems/buds fasciations in the mutant were reversed, accompanied by normalization of mitotic cell division process. Antioxidant defense was downregulated under low glutathione-redox but cysteine-desulfurations and photorespiratory glycolate oxidase transcripts were markedly overexpressed, preventing cysteine overaccumulation but resulted in excess H2O2 in BSO-treated mutant. This led to oxidative damage in proliferating cells, manifested by severe necrosis in rolled-leaf and fasciated stems. Results indicated vital role of glutathione in maintaining abnormal proliferations in plant organs, and its deficiency triggered phenotypic reversal through metabolic diversions of cysteine and concomitant cellular and metabolic modulations.
4 citations
Cites background or methods from "Superoxide-Dismutase Deficient Muta..."
...Overproduction of superoxides and H 2 O 2 was distinctly visible by CLSM study in crop plants [2, 3, 37]....
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...H 2 O 2 was detected by incubation with 25 μM 2 7dichlorofluorescein diacetate (DCF-DA) (excitation 485 nm, emission 530 nm) [37]....
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...Detection and imaging of superoxide radicals in leaf and stem sections were carried out using the fluorescence probe dihydroethidium (DHE), following the earlier method [37]....
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...and Fridovich [36] and detailed earlier [37]....
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...gov) and reports on Phaseolus vulgaris [37], Lens culinaris [15, 46], andArabidopsis thaliana [18, 47]....
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01 Jan 2014
TL;DR: Criticality of foliar H2O2 level in determining As-tolerance of lentil and grass pea genotypes is revealed, which favored plant growth and ensured good grain yield in grasspea varieties even after prolonged As-exposure by effectively preventing oxidative damage.
Abstract: Tolerance of four improved grass pea and lentil genotypes to arsenic (As) was tested in pot experiment using 30 mg As l -1 up to 60 days of growth after commencement of treatment (DAC). As exposure significantly reduced growth and seed yield of lentil variety VLM1 and VLM 4, but no such effect was observed in grass pea variety BioL-202 and PUSA-90-2. Results revealed normal leaf photosynthesis and antioxidant metabolism in both lentil varieties at 20 DAC. However, high superoxide dismutase activity coupled with low ascorbate and glutathione redox and declining ascorbate peroxidase as well as glutathione reductase (GR) level led to abnormal rise in H2O2 content at reproductive stages (40 and 60 DAC), consequently, resulting in significantly enhanced As-induced oxidative damage and physiological impediment in both varieties. By contrast, H2O2 level in both the grass pea varieties were modulated in fine tune at reproductive stage by balanced action of H2O2-metabolizing defense, powered by effective regeneration of glutathione through normal to high GR activity. This favored plant growth and ensured good grain yield in grass pea varieties even after prolonged As-exposure by effectively preventing oxidative damage. Results revealed criticality of foliar H2O2 level in determining As-tolerance of lentil and grass pea genotypes.
4 citations
TL;DR: In this article , the authors compared the nutritional characteristics of raw, boiled, and roasted Tonka beans, and found that the cooking methods decreased the nutritive factors in Tonka Beans.
Abstract: (1) Background: The purpose of this study was to compare the nutritional characteristics of Tonka beans according to the cooking method and to prove the feasibility of application as an elder-friendly food. (2) Methods: After analyzing the nutritive components, antioxidant activity, and anti-diabetic activity of raw, boiled, and roasted Tonka beans, custards, to which roasted Tonka beans were added, were prepared using a gelling agent to meet the KS viscosity standards (≤1500 mPa.s). (3) Results: The cooking methods decreased the nutritive factors in Tonka beans. However, while boiling caused significant losses, roasting led to minor losses. However, because the elderly should avoid eating uncooked foods for safety reasons, semi-solid elder-friendly food was manufactured with roasted Tonka beans, which caused minor losses compared to boiling. The concentration of each gelling agent satisfying the KS viscosity was less than 0.745% of locust bean gum, 0.734% of κ-carrageenan, and 1.094% of agar. (4) Conclusions: Roasted Tonka beans are suitable for use as an elder-friendly food for the health and safety of the elderly, and it will be possible to promote balanced food intake through the use of gelling agents for the elderly who have difficulty swallowing.
3 citations
25 Feb 2021
TL;DR: In this article, nanocarboxylates of ferrum, molybdenum and germanium metals were used as components of rhizobia inoculation suspension for soybean seed treatment to study the effectiveness of their complex effect on the regulation of the key antioxidant enzyme superoxide dismutase in plants under drought.
Abstract: Soybean is one of the most profitable advanced crops in agricultural production in Ukraine and the world as a whole. Therefore, studies of means of regulation and increase in the adaptive capacity of soybeans in symbiosis with nodule bacteria under the action of unfavourable environmental factors are relevant and should be aimed at the use of complex bacterial compositions involving modern nanotechnological approaches. Nanocarboxylates of ferrum, molybdenum and germanium metals were used as components of rhizobia inoculation suspension for soybean seed treatment to study the effectiveness of their complex effect on the regulation of the activity of the key antioxidant enzyme superoxide dismutase in plants under drought. Various symbiotic systems were used, which included soybean plants and inoculation suspensions based on the active, virulent Tn5-mutant Bradyrhizobium japonicum B1-20 by adding nanoparticles of ferrum, germanium and molybdenum carboxylates to the culture medium in a ratio of 1: 1000. Citric acid was the chelator. A model drought lasting 14 days was created during the period of active fixation of atmospheric molecular nitrogen by root nodules of soybeans in the budding and flowering stages, by means of controlled watering of plants to 30% of the total moisture content. In the stage of bean formation, watering of plants was resumed to the optimal level – 60% of the total moisture content. The control was soybean plants, the seeds of which were inoculated with a suspension of rhizobia without the addition of chelated metals. The following research methods were used in the work – microbiological, physiological and biochemical. According to the results, it was found that when nanoparticles of carboxylates of ferrum, molybdenum and germanium were added to the inoculation suspension of rhizobia, there was an increase in superoxide dismutase activity in root nodules and a decrease in soybean leaves under optimal water supply conditions of plants. This indicates the initial changes in the activity of the antioxidant enzyme in these symbiotic systems, induced by the influence of chelated metals in combination with the rhizobia of the active Tn5-mutant B. japonicum B1-20. Prolonged drought induced an increase in the overall level of superoxide dismutase activity in soybean nodules and leaves, compared to plants grown under optimal watering conditions. The symbiotic system formed by soybeans and B. japonicum with molybdenum carboxylate nanoparticles was the most sensitive to long-term drought exposure, compared to two other soybean-rhizobial symbioses using ferrum and germanium nanocarboxylates. This was manifested in the unstable reaction of the enzyme to the action of drought – suppression or intensification of the level of its activity in the root nodules and leaves of soybeans inoculated with rhizobia containing molybdenum carboxylate nanoparticles. In symbiotic systems with the participation of germanium and ferrum nanocarboxylates, slight changes were revealed in superoxide dismutase activity in root nodules and leaves of plants during drought and restoration of enzyme activity to the level of plants with optimal watering after water stress. It is concluded that the addition to the culture medium of rhizobia Tn5-mutant B1-20 of nanocarboxylates of germanium or ferrum is an effective means of regulating the activity of the antioxidant enzyme superoxide dismutase in soybean root nodules and leaves, which can contribute to an increase in the protective properties and adaptation of plants to the action of dehydration.
2 citations
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TL;DR: The 2-Delta Delta C(T) method as mentioned in this paper was proposed to analyze the relative changes in gene expression from real-time quantitative PCR experiments, and it has been shown to be useful in the analysis of realtime, quantitative PCR data.
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TL;DR: The mechanisms of ROS generation and removal in plants during development and under biotic and abiotic stress conditions are described and the possible functions and mechanisms for ROS sensing and signaling in plants are compared with those in animals and yeast.
Abstract: Several reactive oxygen species (ROS) are continuously produced in plants as byproducts of aerobic metabolism. Depending on the nature of the ROS species, some are highly toxic and rapidly detoxified by various cellular enzymatic and nonenzymatic mechanisms. Whereas plants are surfeited with mechanisms to combat increased ROS levels during abiotic stress conditions, in other circumstances plants appear to purposefully generate ROS as signaling molecules to control various processes including pathogen defense, programmed cell death, and stomatal behavior. This review describes the mechanisms of ROS generation and removal in plants during development and under biotic and abiotic stress conditions. New insights into the complexity and roles that ROS play in plants have come from genetic analyses of ROS detoxifying and signaling mutants. Considering recent ROS-induced genome-wide expression analyses, the possible functions and mechanisms for ROS sensing and signaling in plants are compared with those in animals and yeast.
9,908 citations
"Superoxide-Dismutase Deficient Muta..." refers background in this paper
...As can induce oxidative stress through generation of reactive oxygen species (ROS) [4, 5], and moderate accumulation of ROS significantly affects nuclear gene expression [9]....
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...Finally, ROSmight change gene expression by targeting and modifying the activity of transcription factors [9]....
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TL;DR: O2- oxidizes the [4Fe-4S] clusters of dehydratases, such as aconitase, causing-inactivation and release of Fe(II), which may then reduce H2O2 to OH- +OH..
Abstract: O2- oxidizes the [4Fe-4S] clusters of dehydratases, such as aconitase, causing-inactivation and release of Fe(II), which may then reduce H2O2 to OH- +OH.. SODs inhibit such HO. production by scavengingO2-, but Cu, ZnSODs, by virtue of a nonspecific peroxidase activity, may peroxidize spin trapping agents and thus give the appearance of catalyzing OH. production from H2O2. There is a glycosylated, tetrameric Cu, ZnSOD in the extracellular space that binds to acidic glycosamino-glycans. It minimizes the reaction of O2- with NO. E. coli, and other gram negative microorganisms, contain a periplasmic Cu, ZnSOD that may serve to protect against extracellular O2-. Mn(III) complexes of multidentate macrocyclic nitrogenous ligands catalyze the dismutation of O2- and are being explored as potential pharmaceutical agents. SOD-null mutants have been prepared to reveal the biological effects of O2-. SodA, sodB E. coli exhibit dioxygen-dependent auxotrophies and enhanced mutagenesis, reflecting O2(-)-sensitive biosynthetic pathways and DNA damage. Yeast, lacking either Cu, ZnSOD or MnSOD, are oxygen intolerant, and the double mutant was hypermutable and defective in sporulation and exhibited requirements for methionine and lysine. A Cu, ZnSOD-null Drosophila exhibited a shortened lifespan.
3,298 citations
"Superoxide-Dismutase Deficient Muta..." refers background in this paper
...and constitute the first line of defense against the toxicity of superoxide radicals [1, 2]....
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...The toxicity of superoxide radicals has been attributed to their interactionwith other cellular constituents, in particular with hydrogen peroxide [1]....
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TL;DR: The finding that the upstream sequences of Mn and peroxisomal Cu/Zn SODs have three common elements suggests a common regulatory pathway, which is borne out in the research literature.
Abstract: Reactive O2 species (ROS) are produced in both unstressed and stressed cells. Plants have welldeveloped defence systems against ROS, involving both limiting the formation of ROS as well as instituting its removal. Under unstressed conditions, the formation and removal of O2 are in balance. However, the defence system, when presented with increased ROS formation under stress conditions, can be overwhelmed. Within a cell, the superoxide dismutases (SODs) constitute the first line of defence against ROS. Specialization of function among the SODs may be due to a combination of the influence of subcellular location of the enzyme and upstream sequences in the genomic sequence. The commonality of elements in the upstream sequences of Fe, Mn and CuuZn SODs suggests a relatively recent origin for those regulatory regions. The differences in the upstream regions of the three FeSOD genes suggest differing regulatory control which is borne out in the research literature. The finding that the upstream sequences of Mn and peroxisomal CuuZn SODs have three common elements suggests a common regulatory pathway. The tools are available to dissect further the molecular basis for antioxidant defence responses in plant cells. SODs are clearly among the most important of those defences, when coupled with the necessary downstream events for full detoxification of ROS.
2,378 citations
"Superoxide-Dismutase Deficient Muta..." refers background or methods in this paper
...Based on the metal cofactor used by the enzyme, SODs are classified into three groups as iron SOD (Fe SOD), manganese SOD (Mn SOD), and copperzinc SODs (Cu/Zn SOD) [3]....
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...Cu/Zn SOD is normally quite stable, due in large part to copper and zinc binding and oxidation of an intramolecular disulfide [3]....
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...SOD isozymes are located in different cellular compartments [3]....
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...The Cu/Zn SODs are the most prolific SOD isozymes in chloroplast [3, 43, 44], and therefore their overexpression has immense significance in ROS metabolism and oxidative balance in leaves of present As-treated mother plants and mutant lines....
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...Information about structural and functional aspects of SOD isozymes could benefit agricultural crop production through a better understanding of the genetic programs by which plants optimize photosynthetic activity in their green tissues during diverse types of stress conditions [3, 22, 25]....
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