Response of sulfate transporters, thiol metabolism, and antioxidant defense system was studied in roots of two lentil (Lens culinaris Medik.) genotypes grown in arsenic (10, 25, and 40 μM AsV)-supplemented nutrient solution, and significant changes compared to control (0 μM AsV) were observed mainly at 25 and 40 μM. In L 414, high glutathione (GSH) redox (0.8-0.9) was maintained with elevated thiol synthesis, powered by transcriptional up-regulation of LcSultr1;1 and LcSultr1;2 sulfate transporters and significant induction of LcSAT1;1 and LcSAT1;2 (serine acetyltransferase), OAS-TL (O-acetylserine(thiol)-lyase), γ-ECS (γ-glutamylcysteine synthetase), and PCS (phytochelatin synthase) genes predominantly within 12-24 h of As exposure at 25 μM and within 6-12 h at 40 μM. This thiolic potency in L 414 roots was effectively complemented by up-regulation of gene expressions and consequent enhanced activities of superoxide dismutase, ascorbate peroxidase (APX), dehydroascorbate reductase, glutathione reductase (GR), and glutathione-S-transferase (GST) isoforms at 25 and 40 μMAs, efficiently scavenging excess reactive oxygen species to prevent onset of As-induced oxidative stress and consequent inhibition of root growth in L 414. In contrast, down-regulation of vital sulfate-uptake transporters as well as entire thiol-metabolizing system and considerably low APX, GST, and GR expressions in DPL 59 not only resulted in reduced GSH redox but also led to over-accumulation of H2O2. This triggered membrane lipid peroxidations as the marks of As-induced oxidative damage. Results indicated coordinated response of thiol-metabolism and antioxidant defense in conferring As-tolerance in lentil, and GSH is the key point in this cascade. © 2013 Springer-Verlag Wien.

D TALUKDAR

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Protoplasma

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. © 2015, Botanical Society of Sao Paulo.

Revista Brasileira de Botanica

Glutathione deficiency in a grass pea (Lathyrus sativus L.) mutant reveals major reshuffle in up-stream thiol cascade and down-stream antioxidant defense under arsenate stress

Growing plants have a constitutive demand for thiol (sulfur) to synthesize protein, sulfolipid, and other essential sulfur (S)-containing molecules for growth. The uptake and subsequent distribution of sulfate is regulated in response to demand and environmental factors. Sulfate transport consists of both constitutive and sulfur nutrition-dependent regulated transport. The acquisition of sulfur by plants has become an increasingly important concern for the agriculture due to the decreasing trends of S-emissions from industrial sources and the consequent limitation of inputs from deposition. The recognition of the importance of sulfate for plant growth and vigor and hence crop yield, as well as the nutritional importance of sulfur for human and animal diets, has increasingly been recognized. Cysteine synthesis in plants is a fundamental process for protein biosynthesis and all anabolic pathways that require reduced sulfur. Cysteine is the first committed molecule in plant metabolism that contains both sulfur and nitrogen, and, thus, the regulation of its biosynthesis is of utmost importance for the synthesis of a number of essential metabolites in plant pathways. Cysteine is incorporated into proteins and glutathione directly or serves as a sulfur donor for the synthesis of S-containing compounds such as methionine and its derivatives S-adenosylmethionine and S-methylmethionine and many secondary compounds. Furthermore, cysteine acts as a general catalyst in redox reactions through the nucleophilic properties of its sulfur atom, utilizing dithiol–disulfide interchange, as displayed in the thioredoxin and the glutaredoxin systems. Molecular characterization involving transcriptomics, proteomics, and metabolomics profiling in major crops like rice, barley, wheat, maize, and legumes along with model plant Arabidopsis thaliana revealed that sulfate uptake, distribution, and reductive assimilation are regulated in fine-tune depending on sulfur status and demand and that this cascade is integrated with plant photosynthesis, nutrient transports, antioxidant defense system, hormonal signaling, kinase cascades, carbohydrate metabolism, and during plants’ experiences with different biotic and abiotic stresses. This cascade can be manipulated in favor of enhanced plant growth and nutritional benefits—as, for example, effort has been initiated in food and feed legumes (chickpeas, narrow-leafed lupin, soybeans) and other plants with enhanced S-containing amino acids, threonine, glutathione, protein quality, protease inhibitors, and trace elements and with lysine, protein content, and compositions in cereal grains. This emerging prospect can be ushered by using latest cutting-edge functional genomics tools and better understanding of plant thiol-metabolism from source (soil) to sink (grains) in diverse arenas of “thiolomics.” In this chapter, the comprehensive knowledge generated in this area has been compiled and analyzed. © Springer India 2015.

PlantOmics: The Omics of Plant Science

Thiolomics: Molecular mechanisms of thiol-cascade in plant growth and nutrition

A Lathyrus sativus L. mutant isolated in ethylmethane sulfonate-treated Mprogeny 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 Hin 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. © 2014 Dibyendu Talukdar and Tulika Talukdar.

Fulltext

BioMed Research International

Leaf rolling and stem fasciation in grass pea (Lathyrus sativus l.) mutant are mediated through glutathione-dependent cellular and metabolic changes and associated with a metabolic diversion through cysteine during phenotypic reversal

The modulation of antioxidant defense and cytogenetic parameters was studied in Lathyrus sativus L. roots at 3 different ploidies under a control treatment (0 μM) and 5, 10, 25, and 50 μM of CdCl2 in nutrient media. Root growth was inhibited in diploids from 10 μM and in triploid from 25 μM. Growth was normal in tetraploid roots. Although Cd accumulated in ascending order of ploidy, perturbation of antioxidant defense was the severest in diploid, moderate in triploids, and not observed in tetraploid roots even at 50 μM. Low antioxidant enzyme activities led to overaccumulation of H2O2, consequently resulting in oxidative damage through membrane lipid peroxidation in treated diploid roots. Cd-induced chromotoxicity was exhibited by low mitotic fidelity in diploid chromosomes and to some extent in triploids. DNA base-specific fluorescent chromosome banding revealed GC to AT transition and even perturbation of the GC-rich region in the nucleolar organizing chromosome in diploid, presumably facilitating chromosome breakage at a lower ploidy level due to Cd treatment. By contrast, the normal to enhanced GC region was associated with a low percentage of chromosome breakage and other anomalies at higher ploidies exposed to Cd. Results suggest better tolerance of grass pea genotypes to Cd at elevated ploidy levels. © TUBITAK.

Turkish Journal of Botany

Increasing nuclear ploidy enhances the capability of antioxidant defense and reduces chromotoxicity in Lathyrus sativus roots under cadmium stress

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 M 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 H 2O2 in leaves of double mutant. © 2013 Dibyendu Talukdar and Tulika Talukdar.

Superoxide-dismutase deficient mutants in common beans (Phaseolus vulgaris L.): Genetic control, differential expressions of isozymes, and sensitivity to arsenic

Journal of Experimental Botany

Transcripts of sulphur metabolic genes are co-ordinately regulated in developing seeds of common bean lacking phaseolin and major lectins

Frontiers in Physiology

Arsenic Toxicity: The Effects on Plant Metabolism

Chemosphere

Arsenic tolerances in rice (Oryza sativa) have a predominant role in transcriptional regulation of a set of genes including sulphur assimilation pathway and antioxidant system

The Arabidopsis Book

Glutathione

Water, Air, & Soil Pollution

Arsenic Contamination in Rice, Wheat, Pulses, and Vegetables: A Study in an Arsenic Affected Area of West Bengal, India

Coordinated response of sulfate transport, cysteine biosynthesis, and glutathione-mediated antioxidant defense in lentil (Lens culinaris Medik.) genotypes exposed to arsenic

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Publisher	Data powered by TypesetSpringer-Verlag Wien
ISSN	0033-183X