Reduced Glutathione Protects Subcellular Compartments From Pb-Induced ROS Injury in Leaves and Roots of Upland Cotton (Gossypium hirsutum L.)

Abstract

Heavy metals-based changes in the plants and their alleviation through eco-friendly agents including reduced glutathione (GSH) have been widely studied. In the present experiment, we tested the alleviatory role of reduced glutathione (GSH) in seedlings of upland cotton cultivar, TM-1 under lead (Pb) toxicity. Plants were grown in the Hoagland solution containing Pb (0 µM), Pb (500 µM), GSH (50 µM), and GSH + Pb (50 µM + 500 µM). Lead exposure exacerbated hydrogen peroxide (H 2 O 2 ) and hydroxyl radical (OH • ) levels, induced lipid peroxidation (MDA), and decreased the activities of catalase (CAT) and ascorbate peroxidase (APX) in the terminal and median leaves of 28-days old cotton seedlings stressed for 10 days. However, in the primary and secondary roots, CAT activity was increased but APX decreased. Similarly, peroxidase (POD) and superoxide dismutase (SOD) activities were enhanced in the median leaves but a declining trend was observed in the terminal leaves, primary roots and secondary roots. Glutathione reductase (GR) activity, ascorbic acid (AsA) contents and GSH concentrations were increased in all parts except AsA in the median leaves. Transmission electron micrographs of Pb-treated plants exhibited deformed cell wall and cell membrane, disfigured chloroplasts and irregularly shaped mitochondria in the terminal and median leaves. Further, cell membrane, mitochondria, nucleus and other cell organelles in root cells were severely affected by the Pb. Thus their identification was little bit difficult through ultramicroscopy. External GSH stabilized leaf and root ultramorphology by stabilizing cell membranes, stimulating formation of multivesicular body vesicles, and by maintaining structural integrity of other organelles. Evidently, GSH played major alleviatory role against Pb toxicity in upland cotton.

How to Cope with the Challenges of Environmental Stresses in the Era of Global Climate Change: An Update on ROS Stave off in Plants

“…It contains a heme moiety at the active site and converts two H 2 O 2 molecules to oxygen and water. Multiple molecular forms of CAT isozymes (monofunctional CAT or typical CAT, CAT peroxidase, pseudo-CAT, or Mn CAT) indicate their versatile role within the plant system including cotton [146,147].…”

“…Both GR and GSH are physiologically connected, and it is their differential concentration in plants that is significant for plant defense operations against oxidative stress [148]. Previously, enhanced cesium stress has been observed to upregulate GSH activity in Arabidopsis, stimulating the antioxidant system [147].…”

Seed Priming with Brassinosteroids Alleviates Chromium Stress in Rice Cultivars via Improving ROS Metabolism and Antioxidant Defense Response at Biochemical and Molecular Levels

“…As a result, physiological processes besides growth inhibition also occur in rice seedlings. To scavenge the higher production of MDA and H 2 O 2 , the antioxidant defense mechanism (SOD, POD, CAT, and APX) is stimulated in plants [54,55]. In a recent study, Khan et al [56] revealed that EBL significantly increased plant growth and triggered the antioxidant defense system in wheat plants against drought stress.…”

Biochar amendment reduced the risk associated with metal uptake and improved metabolite content in medicinal herbs

“…The exposure of Pb and Cd in roots of W. somnifera deformed the parenchyma cells before pericycle lignification, as reported earlier under Cd stress (Shah et al, 2019). The change in orientation of subcellular organelles in primary and secondary roots of cotton (Khan et al, 2020) under Pb stress and the changes in the ultrastructure of chloroplasts and nucleus due to Cd stress in rice (Daud et al, 2016) are reported earlier. The replacement of essential metals (such as calcium, zinc, and iron) by Pb and Cd hinders the functions of enzymes using a metal cofactor and is reported in a large number of studies (Aguzie et al, 2021; Fatima et al, 2020; Rizwan et al, 2017).…”