title: Proline and glycinebetaine enhance antioxidant defense and methylglyoxal detoxification systems and reduce NaCl-induced damage in cultured tobacco cells.
abstract: Salt stress impairs reactive oxygen species (ROS) and methylglyoxal (MG) detoxification systems, and causes oxidative damage to plants. Up-regulation of the antioxidant and glyoxalase systems provides protection against NaCl-induced oxidative damage in plants. Thiol-disulfide contents, glutathione content and its associated enzyme activities involved in the antioxidant defense and glyoxalase systems, and protein carbonylation in tobacco Bright Yellow-2 cells grown in suspension culture were investigated to assess the protection offered by proline and glycinebetaine against salt stress. Salt stress increased protein carbonylation, contents of thiol, disulfide, reduced (GSH) and oxidized (GSSG) forms of glutathione, and the activity of glutathione-S-transferase and glyoxalase II enzymes, but decreased redox state of both thiol-disulfide and glutathione, and the activity of glutathione peroxidase and glyoxalase I enzymes involved in the ROS and MG detoxification systems. Exogenous application of proline or glycinebetaine resulted in a reduction of protein carbonylation, and in an increase in glutathione redox state and activity of glutathione peroxidase, glutathione-S-transferase and glyoxalase I under salt stress. Neither proline nor glycinebetaine, however, had any direct protective effect on NaCl-induced GSH-associated enzyme activities. The present study, therefore, suggests that both proline and glycinebetaine provide a protective action against NaCl-induced oxidative damage by reducing protein carbonylation, and enhancing antioxidant defense and MG detoxification systems.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
authors.forename: Md Anamul
authors.initials: MA
authors.lastname: Hoque
authors.forename: Mst Nasrin Akhter
authors.initials: MN
authors.lastname: Banu
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Shimoishi
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Murata
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D001622:Betaine / Q000494:pharmacology*; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects; D004220:Disulfides / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D008658:Inactivation, Metabolic; D007791:Lactoylglutathione Lyase / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D011392:Proline / Q000494:pharmacology*; D050050:Protein Carbonylation / Q000187:drug effects; D011765:Pyruvaldehyde / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013869:Thiolester Hydrolases / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology; D000099301:Hydroxyacylglutathione Hydrolase
chemical_list: D000975:Antioxidants; D001622:Betaine; D004220:Disulfides; D005978:Glutathione; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; D007791:Lactoylglutathione Lyase; D011392:Proline; D011765:Pyruvaldehyde; D012965:Sodium Chloride; D013438:Sulfhydryl Compounds; D013869:Thiolester Hydrolases; D000099301:Hydroxyacylglutathione Hydrolase