RETRACTED ARTICLE: Coordinated response of sulfate transport, cysteine biosynthesis, and glutathione-mediated antioxidant defense in lentil (Lens culinaris Medik.)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

Abstract

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 As(V))-supplemented nutrient solution, and significant changes compared to control (0 μM As(V)) 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.

Glutathione and proline can coordinately make plants withstand the joint attack of metal(loid) and salinity stresses

“…Elevated concentrations of metals (such as As, Cd, Cr, Hg, Ni, and Pb) may affect photosynthetic apparatus, electron transport chain and chlorophyll biosynthesis, induce cellular damage, impair cellular redox homeostasis, and finally cause cellular metabolic arrest (Anjum et al, 2010, 2012a; Gill and Tuteja, 2010; Talukdar, 2012; Talukdar and Talukdar, 2014). Saline soil conditions, on the other hand, can cause osmotic stress that in turn can inhibit cell expansion and cell division, impact stomatal closure, induce cell turgor via lowering water potential, and alter the normal homeostasis of cells (Miller et al, 2010).…”

“…Diverse plant taxa have been reported to adapt metabolically to salinity and exposure to metals by enhancing synthesis of sulfur (S)-rich peptides (such as glutathione, GSH) and low-molecular-weight nitrogenous and proteogenic amino acids/osmolytes (such as proline, Pro) (Khan et al, 2009; Anjum et al, 2010, 2012a; Talukdar, 2012; Kishor and Sreenivasulu, 2014; Talukdar and Talukdar, 2014). Nevertheless, both GSH and Pro share L-glutamate as a common biosynthesis precursor (Moat et al, 2003) (Figure 1).…”

Differential Response of Cysteine-deficient Lentil (<i>Lens culinaris</i> Medik.) Mutants Impaired in Foliar O-acetylserine(thiol)-lyase Expression

“…Variance analysis was performed on all experimental data, and statistical significance (P<0.05) of means was determined by Duncan's multiple range tests using SPSS software (SPS Inc., USA v. 10.0). (Talukdar and Talukdar, 2014), common beans (Talukdar and Talukdar, 2013b) and Arabidopsis thaliana (Han and Kim, 2006). The qRT-PCR cycling stages consisted of initial denaturation at 94°C (3 min), followed by 35 cycles of 94°C (5 s), 62°C (10s),72°C (10 s) and a final extension stage at 72°C (2 min).…”

“…Cysteine is incorporated into proteins and glutathione (GSH) directly (Wirtz and Hell, 2006 (Wirtz and Hell, 2006;Lo´pez-Martı´n et al, 2008). Recently, two novel catalase-deficient mutants differing in antioxidant defence response have been isolated and genetically characterized in lentil (Talukdar and Talukdar, 2013a) and coordinated expression of genes involved in sulphur metabolisms during stress tolerance has been revealed (Talukdar and Talukdar, 2014). In this on-going investigation to identify novel biochemical mutants, two plants exhibiting poor growth potential and very low seed cysteine content have been isolated in M 2 -progeny of lentil variety L 414.…”

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

“…Significant genotypic differences in toxicity tolerance were observed in 99 pea genotypes under 5-50 µM Cd (Belimov et al, 2003;Metwally et al, 2005), a lentil genotype exposed to 20 and 40 µM Cd (Talukdar, 2012b), Brassica species (Tickoo et al, 2007;Bauddh and Singh, 2011), and cereals and many other crop plants (Tran and Popova, 2013). Modulations of the interrelated network of physiological and molecular mechanisms, such as 1) metal uptake, intercellular transport, and accumulation; 2) efflux of metals from cytoplasm to extraplasmatic compartments including vacuoles through complexation with various substances, especially thiol-containing phytochelatins and metallothioneins; 3) the nature of antioxidant defense response and detoxifications; and 4) coordinated response, activation, or modification of metabolic functioning and rapid repair of damaged cell structures under the guidance of nuclear and/or epigenetic genome, have primarily been attributed to differential levels of toxicity of heavy metals like Cd in different plants (Metwally et al, 2005;Rodríguez-Serrano et al, 2009;Dai et al, 2013;Hussain et al, 2013;Cansaran Duman et al, 2014;Talukdar and Talukdar, 2014b). In non-hyperaccumulating plants, metals/metalloids are often immobilized and sequestered Figure 5.…”