Limited sulfur resource forces Arabidopsis thaliana to shift towards non-sulfur tolerance under cadmium stress

Cadmium Bioavailability, Uptake, Toxicity and Detoxification in Soil-Plant System

“…The SOD superoxide dismutase, APX ascorbate peroxidise, GPX guaiacol peroxidase, CAT catalase, PPO polyphenol oxidase, GR glutathione reductase, AsA ascorbic acid, GSH glutathione, GST Glutathione S-transferase, ACOX acyl co-A oxidase, POD peroxidase, DHAR dehydroascorbate reductase, MDHAR monodehydroascorbate reductase, LOX lipoxygenase, AAO ascorbic acid oxidase, SDH succinatedehydrogenase, PROX proline oxidase activation of GR by Cd has been reported by Bashir et al (2013), Saidi et al (2014) and Howladar (2014). Ascorbic Acid (AsA) is the most abundant antioxidative enzyme in plants and participates in H 2 O 2 detoxification via the AsA-GSH cycle which involves (among other things) AsA, GSH, APX, and GR Chao et al 2010).…”

“…Owing to its unique nucleophilic and redox properties, GSH plays a key role in physiological functions such as transport of GSH-conjugated amino acids and intracellular redox state regulation (Deng et al 2010). As an important antioxidant, GSH takes part in bio-reductive reactions as an ROS scavenger to relieve cells from oxidative stress (Park et al 2012;Bashir et al 2013), becoming oxidized to GSSG in the process (Shahid et al 2014f). The antioxidant properties of GSH depend on the oxidation of the SH group, giving rise to GSSG (Márquez-García et al 2011).…”

“…Based on the results of light microscopy work with D. carota, Corguinha et al (2012) proposed that Cd affects plant growth in two separate phases, with the first phase impacting the functional and cytological events (1-4 days of Cd exposure), and the second phase impacting cell to cell separation, cell hypertrophy, and thiol-peptide content (4-14 days of Cd exposure). Cadmium is also known to inhibit photosynthesis by a variety of means including: reducing the transcription of genes which are related photosynthesis such as rbcL, psaB and psbA (Qian et al 2010); inactivating Rubisco and phosphoenol pyruvate carboxylase (Bashir et al 2013); inducing lipid peroxidation (Iannone et al 2010), interfering with protochlorophyllide production (Prasad 2004), reducing the activity of enzymes involved in CO 2 fixation and inhibiting chlorophyll biosynthesis (Stobart et al 1985); enhancing proteolysis (Pena et al 2007); interfering with leaf transpiration through changes in stomatal conductance and stomatal density (Souza et al 2011;Baryla et al 2001) and; disturbing nutrient metabolism and plant antioxidant machinery (Gill and Tuteja 2010). For B. napus, Cd application has also been found to reduce the concentration of leaf pigments, including lutein, neoxanthin, β-carotene and violaxanthin (Baryla et al 2001).…”

Reducing the bioavailability of cadmium in contaminated soil by dithiocarbamate chitosan as a new remediation

“…Chlorophyll content is a useful indicator of the photosynthetic activity of plants. It has previously been reported that Cd affected chlorophyll content directly by degrading the chloroplast and reacting with the thiol groups of protochlorophyllide reductase or other enzymes involved in the synthesis of 5-aminolevulinic acid (Bashir et al 2013;Stobart et al 1985). In this study, we found that the plants showed severe chlorosis and the chlorophyll content decreased sharply under Cd stress.…”

Thylakoidal Pigment-Protein Complexes: Critical Requirement of Sulphur for Proper Assemblage and Photosynthesis in Arabidopsis thaliana

“…One-fifteenth to the nitrogen in plant dry matter sulphur plays crucial roles in the catalytic or electrochemical functions of biomolecules in the cells [1]. It is found in amino acids (Cys and Met), oligopeptides (glutathione [GSH] and phytochelatins), vitamins and cofactors (biotin, thiamine, CoA, and S-adenosyl-Met), and a variety of secondary products [2,3]. The thiol (sulfhydryl) group of Cys in proteins maintains protein structure by forming disulfide bonds between two Cys residues via oxidation.…”