Cross-adaptation to cadmium stress in Plantago ovata by pre-exposure to low dose of gamma rays: Effects on metallothionein and metal content
13 May 2015-International Journal of Radiation Biology (Int J Radiat Biol)-Vol. 91, Iss: 8, pp 611-623
TL;DR: Higher Cd accumulation in P. ovata seedlings may be attributed to the upregulation of PoMT genes in gamma pretreated seedlings, indicated its positive role against Cd-mediated cytotoxic and genotoxic effects.
Abstract: Purpose: To investigate the effects of gamma pre-exposure on cadmium accumulation in Plantago ovata seedlings Metallothionein (MT) localization was also studied following Cadmium (Cd) treatment in P ovataMaterials and methods: DNA damage was determined by alkaline comet assay MT gene and protein expression were studied by real-time polymerase chain reaction and flow cytometry, respectively, in root and shoot tissues Metal accumulation (Cd, zinc [Zn], iron [Fe]) was evaluated by Atomic Absorption SpectroscopyResults: Cd treatment decreased seed germination rate, biomass and free radical scavenging activity and increased DNA damage in a dose-dependent manner When P ovata seeds were pre- exposed to 5 Gy gamma dose (prior to Cd treatment) seed germination rate, biomass and free radical scavenging activity increased significantly MT genes (PoMT1, PoMT2 and PoMT3) and MT protein expression enhanced when 5 Gy gamma-irradiated seeds were grown in Cd containing medium and Cd accumulation also incr
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TL;DR: The present review will provide an up-date of the current knowledge on seed pre-germinative metabolism, gathering the most relevant results from physiological, genetics, and omics studies conducted in model and crop plants.
Abstract: The pre-germinative metabolism is among the most fascinating aspects of seed biology. The early seed germination phase, or pre-germination, is characterized by rapid water uptake (imbibition), which directs a series of dynamic biochemical events. Among those are enzyme activation, DNA damage and repair, and use of reserve storage compounds, such as lipids, carbohydrates and proteins. Industrial seedling production and intensive agricultural production systems require seed stocks with high rate of synchronized germination and low dormancy. Consequently, seed dormancy, a quantitative trait related to the activation of the pre-germinative metabolism, is probably the most studied seed trait in model species and crops. Single omics, systems biology, QTLs and GWAS mapping approaches have unveiled a list of molecules and regulatory mechanisms acting at transcriptional, post-transcriptional and post-translational levels. Most of the identified candidate genes encode for regulatory proteins targeting ROS, phytohormone and primary metabolisms, corroborating the data obtained from simple molecular biology approaches. Emerging evidences show that epigenetic regulation plays a crucial role in the regulation of these mentioned processes, constituting a still unexploited strategy to modulate seed traits. The present review will provide an up-date of the current knowledge on seed pre-germinative metabolism, gathering the most relevant results from physiological, genetics, and omics studies conducted in model and crop plants. The effects exerted by the biotic and abiotic stresses and priming are also addressed. The possible implications derived from the modulation of pre-germinative metabolism will be discussed from the point of view of seed quality and technology.
43 citations
Cites background from "Cross-adaptation to cadmium stress ..."
...The cross-adaptation to Cd stress has been studied in Plantago ovata (an economically and medicinally important plant of the Plantaginaceae family) after pre-exposure to low doses of c-radiation (Ghoshal et al. 2015)....
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...has been studied in Plantago ovata (an economically and medicinally important plant of the Plantaginaceae family) after pre-exposure to low doses of c-radiation (Ghoshal et al. 2015)....
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01 Jan 2021
TL;DR: The effect of two essential and two nonessential heavy metals—copper, zinc, and cadmium and lead, respectively, and their effects on plants in general are discussed and downregulations in the expression of metallothionein type 2 gene are observed.
Abstract: Polyamines are naturally occurring secondary metabolites that are known to possess nonenzymatic antioxidant properties. They are carbon- and nitrogen-containing polycationic compounds (at physiologic pH) and are widely found in plants, animals, and bacteria. The three most predominant polyamines in plants are putrescine, spermidine, and spermine. Putrescine serves as the precursor molecule in the subsequent biosyntheses of spermidine and spermine. Plants under oxidative stress have enhanced endogenous polyamine levels. Polyamines combat oxidative stress by scavenging the free radicals. The exogenous addition of polyamines to growth medium is found to be beneficial for plants as it happened to alleviate the damage caused by oxidative stress. Polyamines are known to bind metals and this can be an implication at their mode of action in mitigating stress. Metallothioneins, on the other hand, are gene-encoded protein products that function as a nonenzymatic, antioxidant system in plants. Metallothioneins are low molecular weight, cysteine-rich polypeptides that are responsive to heavy metal stress, and their gene expression is induced by oxidative stress of different kinds. Metallothioneins have cysteine-rich N- and C-terminal domains that bind heavy metal ions, mostly, Cu, Zn, and Cd. Among the various kinds of oxidative stress, heavy metal-induced stress has become a serious concern in recent years. Plants are regularly being exposed to heavy metal-induced toxicity and this is affecting the food (e.g., Oryza sativa, Triticum aestivum, Zea mays) and the cash (e.g., Brassica juncea, Brassica napus, Hordeum vulgare, Sesamum indicum) crops at large. Heavy metals are defined as those metals and metalloids which have an atomic number greater than 20 and density 5 g cc− 1 and also have properties of metals. Essential and nonessential heavy metals, when present in the soil in an excess concentration, causes reactive oxygen species (ROS) generation. ROS contains unpaired electron(s) which causes oxidative damage to the plants which ultimately leads to the death of the plant. In this review, we discuss the effect of two essential and two nonessential heavy metals—copper, zinc, and cadmium and lead, respectively, and their effects on plants in general. Plantago ovata is a medicinally and commercially vital crop with a repertoire of antioxidant compounds like polyphenols, flavonoids, metallothionein (types 1, 2, and 3), phytochelatins, and polyamines present in it and it is the test system. The biochemical and molecular alterations that occur due to the exposure of P. ovata to copper, zinc, cadmium, and lead are discussed in this review. This review also talks of how metallothionein genes and especially type 2 metallothionein in P. ovata aid in tolerance and homeostasis of the four heavy metals—Zn, Cu, Cd, and Pb; and their differential expressions. This study also demonstrates alteration in metallothionein type 2 (PoMT2) expression of P. ovata in the presence of polyamines putrescine, spermidine, and spermine in addition to ZnSO4·H2O by semiquantitative and quantitative PCR techniques. When P. ovata seedlings are exposed to heavy metals—Cu, Zn, Cd, and Pb, they showed increased expressions of metallothionein type 2. We have observed downregulations in the expression of metallothionein type 2 gene in the presence of polyamines, putrescine, spermidine, and spermine, which implies their concerted protective and antioxidant activities to fight against the zinc-induced oxidative stress. This review also shows phytochelatins, which are naturally produced by plants in vivo, in response to oxidative stress induced by heavy metals. They are also cysteine-rich peptides which aid in heavy metal homeostasis and detoxification—a function very similar to metallothioneins and hence also classified as class III metallothioneins. Concerted action of all the heavy metal chelating entities has been emphasized in this study
20 citations
TL;DR: The enhanced expression of MT2 gene in Plantago ovata has a correlation with the increased total antioxidant activity and increased DPPH radical scavenging activity and this study observed an upregulation in the PoMT2 gene expression level in 500 and 800 µM ZnSO4·7H2O treated samples but found saturation on further increasing the dose.
Abstract: Plantago ovata Forsk is an annual herb with immense medicinal importance, the seed and husk of which is used in the treatment of chronic constipation, irritable bowel syndrome, diarrhea since ancient times. Zinc, an essential metal, is required by plants as they form important components of zinc finger proteins and also aid in synthesis of photosynthetic pigments such as chlorophyll. However, in excess amount Zn causes chlorosis of leaf and shoot tissues and generate reactive oxygen species. The present study is aimed at investigating the changes in expression levels of MT2 gene in Plantago ovata under zinc stress. Data show up to 1.66 fold increase in expression of PoMT2 in 1000 µM ZnSO4·7H2O treated sample. Our study also describes alteration of MT2 gene expressions in Plantago ovata as observed through Real time PCR (qPCR) done by $$2^{{ - \Delta \Delta}} C_T$$
method. In this study we have observed an upregulation (or induction) in the PoMT2 gene expression level in 500 and 800 µM ZnSO4·7H2O treated samples but found saturation on further increasing the dose to 1000 µM of ZnSO4·7H2O. Determination of the phenotypic and biochemical changes in Plantago ovata due to exposure to zinc stress of concentrations 500, 800 and 1000 µM revealed oxidative stress. The enhanced expression of MT2 gene in Plantago ovata has a correlation with the increased total antioxidant activity and increased DPPH radical scavenging activity.
13 citations
Cites background from "Cross-adaptation to cadmium stress ..."
...ovata scavenged DPPH radical in a very similar manner (Kapoor et al. 2014; Ghoshal et al. 2015)....
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...Cd treated ethanolic plant extracts of Brassica juncea and P. ovata scavenged DPPH radical in a very similar manner (Kapoor et al. 2014; Ghoshal et al. 2015)....
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01 Jan 2021
TL;DR: In this article, a comparative study on the role of metallothionein and phytochelatins in combating copper-induced oxidative stress in brinjal (Solanum melongena), an important vegetable plant with immense nutritional value.
Abstract: Plants, though sessile, have various enzymatic and nonenzymatic antioxidant systems which help them in combating the heavy metal-induced oxidative stress and various other abiotic stresses. Metallothioneins (MTs) and Phytochelatins (PCs) are the two best characterized heavy metal-binding ligands in plants. In the present investigation, we made a comparative study on the role of metallothionein and PCs in combating copper-induced oxidative stress in brinjal (Solanum melongena), an important vegetable plant with immense nutritional value. Seedlings were exposed to various sublethal doses of copper and grew them for a period of 1 month. We studied the relative expression of these genes by reverse transcription PCR and real-time PCR techniques and the relative content of the major secondary metabolites and phytochelatins by High-Performance Liquid Chromatographic (HPLC) technique. In both cases, we find that 800 µM is the highest dose that the plants can withstand. On further increasing the dose to 1000 µM, a sudden drop in the expression of the genes, as well as polyphenolic and phytochelatin compound contents, was observed. This observation proves that phytochelatin and metallothionein function in a coordinated way to chelate, detoxify, and rendering the plant more tolerant to metal stress.
2 citations
TL;DR: In this paper , the role of dopamine in apple under Cd stress was explored, and the results indicated that dopamine significantly increased the activity of antioxidant enzymes to reduce the reactive oxygen species (ROS) level.
Abstract: Cadmium (Cd) is an element that is not only unnecessary for plant growth, but can also induce irreversible damage to plants. Dopamine (DA) and tyrosine decarboxylase (TyDC), a key protein in its synthesis, play important roles in responses to biotic and abiotic stress in plants. To explore the role of dopamine in apple under Cd stress, Malus hupehensis seedlings and TyDC transgenic plants were treated with 0 and 300 μmol L−1 CdCl2 solutions. We demonstrated that the application of dopamine alleviated Cd stress-induced growth retardation, and the chlorophyll content increased by 22.5%. The root vigor and photosynthesis increased by 1.10 and 1.01 times, respectively. Dopamine significantly increased the activity of antioxidant enzymes to reduce the reactive oxygen species (ROS) level. The accumulation of Cd2+ in the roots and shoots of apple plants was decreased by 33.7% and 28.6% under dopamine treatment, and the phytohormone levels were noticeably increased. Dopamine and MdTyDC alleviated Cd stress by markedly increasing the content of free amino acids and phenolic compounds following Cd exposure. In addition, exogenous dopamine and MdTyDC overexpression alleviated Cd stress by regulating the expression of genes involved in Cd uptake, transport, and detoxification, including HA7, NRAMP1, NRAMP3, HMA4, PCR2, ABCC1, MHX, NAS1, and MT2. Overall, our findings indicate that dopamine can eliminate ROS by increasing antioxidant enzyme activity and reducing Cd accumulation. In addition, dopamine also increased the levels of phytohormones, amino acids, and phenols under Cd stress and regulated the transcription of Cd transporters to enhance Cd tolerance in apple.
1 citations
References
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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.
Abstract: The two most commonly used methods to analyze data from real-time, quantitative PCR experiments are absolute quantification and relative quantification. Absolute quantification determines the input copy number, usually by relating the PCR signal to a standard curve. Relative quantification relates the PCR signal of the target transcript in a treatment group to that of another sample such as an untreated control. The 2(-Delta Delta C(T)) method is a convenient way to analyze the relative changes in gene expression from real-time quantitative PCR experiments. The purpose of this report is to present the derivation, assumptions, and applications of the 2(-Delta Delta C(T)) method. In addition, we present the derivation and applications of two variations of the 2(-Delta Delta C(T)) method that may be useful in the analysis of real-time, quantitative PCR data.
139,407 citations
TL;DR: Guava fruit extracts were analyzed for antioxidant activity measured in methanol extract and dichloromethane extract (AOAD), ascorbic acid, total phenolics, and total carotenoids contents.
Abstract: Guava fruit extracts were analyzed for antioxidant activity measured in methanol extract (AOAM), antioxidant activity measured in dichloromethane extract (AOAD), ascorbic acid, total phenolics, and total carotenoids contents. The ABTS, DPPH, and FRAP assays were used for determining both AOAM and AOAD, whereas the ORAC was used for determining only AOAM. Averaged AOAM [mM Trolox equivalent (TE)/g fresh mass (FM)] were 31.1, 25.2, 26.1, and 21.3 as determined by the ABTS, DPPH, FRAP, and ORAC assays, respectively. Averaged AOAD (mM TE/g FM) were 0.44, 0.27, and 0.16 as determined by the ABTS, DPPH, and FRAP assays, respectively. AOAM determined by all assays were well correlated with ascorbic acid (0.61prp0.92) and total phenolics (0.81prp0.97) and also among themselves (0.68prp0.97) but had negative correlation with total carotenoids (� 0.67prp� 0.81).
2,737 citations
"Cross-adaptation to cadmium stress ..." refers methods in this paper
...…activity In the present study, the reduction of antioxidant activity of P. ovata seedlings (control, Group I, II and III) was measured in terms of decrease in absorbance of methanolic 1, 1-Diphenyl-2-picryl hydrazyl (DPPH) (Sigma, St Louis, MO, USA) solution at 515 nm (Th aipong et al. 2006)....
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TL;DR: Recent advances in understanding the regulation of PC biosynthesis and MT gene expression and the possible roles of PCs and MTs in heavy metal detoxification and homeostasis are reviewed.
Abstract: ▪ Abstract Among the heavy metal-binding ligands in plant cells the phytochelatins (PCs) and metallothioneins (MTs) are the best characterized. PCs and MTs are different classes of cysteine-rich, heavy metal-binding protein molecules. PCs are enzymatically synthesized peptides, whereas MTs are gene-encoded polypeptides. Recently, genes encoding the enzyme PC synthase have been identified in plants and other species while the completion of the Arabidopsis genome sequence has allowed the identification of the entire suite of MT genes in a higher plant. Recent advances in understanding the regulation of PC biosynthesis and MT gene expression and the possible roles of PCs and MTs in heavy metal detoxification and homeostasis are reviewed.
2,334 citations
"Cross-adaptation to cadmium stress ..." refers background in this paper
...Depending on the sequence and arrangements of cysteine residues in N and C-terminal regions, plant MT are grouped into four types (Cobbett and Goldsbrough 2002)....
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TL;DR: Recently, a major transcription system that controls abscisic-acid-independent gene expression in response to dehydration and low temperature has been identified and it includes the DRE/CRT (dehydration-responsive element/C-repeat) cis-acting element and its DNA-bindingprotein, DREB/CBF (DRE-binding protein/ C-repeat binding factor).
Abstract: Recently, a major transcription system that controls abscisic-acid-independent gene expression in response to dehydration and low temperature has been identified. The system includes the DRE/CRT (dehydration-responsive element/C-repeat) cis-acting element and its DNA-binding protein, DREB/CBF (DRE-binding protein/C-repeat binding factor), which has an AP2 domain. DREB/CBF contains two subclasses, DREB1/CBF and DREB2, which are induced by cold and dehydration, respectively, and control the expression of various genes involved in stress tolerance. Recent studies are providing evidence of differences between dehydration-signaling and cold-stress-signaling cascades, and of cross-talk between them.
1,689 citations
"Cross-adaptation to cadmium stress ..." refers background in this paper
...Th erefore diverse environmental stresses may often activate similar cell signaling pathways and cellular responses, such as the production of stress proteins and up-regulation of anti-oxidant enzymes (Shinozaki and Yamaguchi-Shinozaki 2000, Knight and Knight 2001, Zhu 2001)....
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TL;DR: This review discusses the molecular mechanisms of toxic metal accumulation in plants and algae, the responses to metal exposure, as well as the understanding of metal tolerance and its evolution.
Abstract: Over the past 200 years emissions of toxic heavy metals have risen tremendously and significantly exceed those from natural sources for practically all metals. Uptake and accumulation by crop plants represents the main entry pathway for potentially health-threatening toxic metals into human and animal food. Of major concern are the metalloids arsenic (As) and selenium (Se), and the metals cadmium (Cd), mercury (Hg), and lead (Pb). This review discusses the molecular mechanisms of toxic metal accumulation in plants and algae, the responses to metal exposure, as well as our understanding of metal tolerance and its evolution. The main emphasis will be on cadmium, which is by far the most widely studied of the non-essential toxic metals/metalloids. Entry via Zn2+, Fe2+, and Ca2+ transporters is the molecular basis of Cd2+ uptake into plant cells. Much less is known about the partitioning of non-essential metals and about the genes underlying the enormous diversity among plants with respect to Cd accumulation in different tissues. Numerous studies have described symptoms and responses of plants upon toxic metal exposure. Mysterious are primary targets of toxicity, the degree of specificity of responses, the sensing and the signaling events that lead to transcriptional activation. All plants apparently possess a basal tolerance of toxic non-essential metals. For Cd and As, this is largely dependent on the phytochelatin pathway. Not understood is the molecular biology of Cd hypertolerance in certain plant species such as the metallophytes Arabidopsis halleri or Thlaspi caerulescens.
1,598 citations
"Cross-adaptation to cadmium stress ..." refers background in this paper
...Some plants possess the ability of accumulating Cd to some extent but storage in the aerial parts of plant increases the risk of Cd bioaccumulation in the ecosystem (Clemens 2006)....
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...Cd can be taken up by plants through divalent cation channels present in root and competes with other essential metal ions (especially zinc [Zn] and iron [Fe]) for binding and absorption (Clemens 2006)....
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