Proline and glycinebetaine enhance antioxidant defense and methylglyoxal detoxification systems and reduce NaCl-induced damage in cultured tobacco cells

Proline and Glycinebetaine Ameliorated NaCl Stress via Scavenging of Hydrogen Peroxide and Methylglyoxal but Not Superoxide or Nitric Oxide in Tobacco Cultured Cells

“…Our previous studies indicated that exogenous proline and betaine induce accumulation of more than 200 mM proline and betaine respectively in tobacco BY-2 cells under 200 mM NaCl stress 11) and mitigate NaCl-induced growth inhibition after 4 d of incubation, 11,28) indicating that uptake of compatible solutes plays an important role in the adaptation to osmotic stress due to salinity. Exogenously applied proline and betaine suppress cell death in BY-2 cells accompanied by decreased oxidative damages to lipid membranes and protein under 200 mM NaCl stress, 8,12) suggesting that both compounds are efficient at mitigating most of the deleterious consequences of salt stress after 4 d of incubation, 12) but proline mitigates the inhibitory effects of salt stress more than betaine due to differences in the antioxidant defense and MG detoxification systems. 8,28,29) In the present study, we attempted to clarify the protective mechanisms of proline and betaine in cultured tobacco cell responses to salt stress.…”

“…Exogenously applied proline and betaine suppress cell death in BY-2 cells accompanied by decreased oxidative damages to lipid membranes and protein under 200 mM NaCl stress, 8,12) suggesting that both compounds are efficient at mitigating most of the deleterious consequences of salt stress after 4 d of incubation, 12) but proline mitigates the inhibitory effects of salt stress more than betaine due to differences in the antioxidant defense and MG detoxification systems. 8,28,29) In the present study, we attempted to clarify the protective mechanisms of proline and betaine in cultured tobacco cell responses to salt stress.…”

“…[4][5][6][7] Moreover, proline and betaine provide protection against stress by maintaining redox homeostasis. 8) Under salt stress, exogenous application of proline or betaine upregulates stressprotective proteins, 9) and reduces lipid peroxidation [10][11][12] and protein oxidation. 8) Environmental stress, including salinity, induces the production of hydrogen peroxide (H 2 O 2 ), the superoxide radical (O 2 À ), and nitric oxide (NO) in plant cells.…”

“…8) Under salt stress, exogenous application of proline or betaine upregulates stressprotective proteins, 9) and reduces lipid peroxidation [10][11][12] and protein oxidation. 8) Environmental stress, including salinity, induces the production of hydrogen peroxide (H 2 O 2 ), the superoxide radical (O 2 À ), and nitric oxide (NO) in plant cells. 1,[12][13][14][15][16][17][18] Excess production of H 2 O 2 , O 2 À , and NO is toxic to plants, and causes oxidative damage to cellular constituents, leading to cell death.…”

“…18) There is increasing evidence that both proline and betaine increase antioxidant defense mechanisms and improve stress tolerance in plants as well as in cultured cells. 9,10,18,[25][26][27] We have found that exogenous application of both proline and betaine increases intracellular proline and betaine contents, 11) which leads to the suppression of cell death and improvement of salt tolerance in tobacco Bright Yellow-2 (BY-2) cells via increments in the antioxidant defense and MG detoxification systems, 8,12,28,29) but protective mechanisms of proline and betaine in plant responses to salt stress remain to be clarified. The present study was therefore conducted to investigate the effects of exogenous proline and betaine on intracellular H 2 O 2 , O 2 À , NO, and MG levels and the mRNA levels of glutathione peroxidase (GPX) and glyoxalase I genes in tobacco BY-2 cells exposed to salt stress.…”