title: Proline and glycinebetaine induce antioxidant defense gene expression and suppress cell death in cultured tobacco cells under salt stress.
abstract: Salt stress causes oxidative damage and cell death in plants. Plants accumulate proline and glycinebetaine (betaine) to mitigate detrimental effects of salt stress. The aim of this study was to investigate the protective effects of proline and betaine on cell death in NaCl-unadapted tobacco (Nicotiana tabacum) Bright Yellow-2 suspension-cultured cells subjected to salt stress. Salt stress increased reactive oxygen species (ROS) accumulation, lipid peroxidation, nuclear deformation and degradation, chromatin condensation, apoptosis-like cell death and ATP contents. Neither proline nor betaine affected apoptosis-like cell death and G(1) phase population, and increased ATP contents in the 200mM NaCl-stressed cells. However, both of them effectively decreased ROS accumulation and lipid peroxidation, and suppressed nuclear deformation and chromatin condensation induced by severe salt stress. Evans Blue staining experiment showed that both proline and betaine significantly suppressed increment of membrane permeability induced by 200mM NaCl. Furthermore, among the ROS scavenging antioxidant defense genes studied here, mRNA levels of salicylic acid-binding (SAbind) catalase (CAT) and lignin-forming peroxidase (POX) were found to be increased by proline and betaine under salt stress. It is concluded that both proline and betaine provide a protection against NaCl-induced cell death via decreasing level of ROS accumulation and lipid peroxidation as well as improvement of membrane integrity.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
authors.forename: Nasrin Akhter
authors.initials: NA
authors.lastname: Banu
authors.forename: Anamul
authors.initials: A
authors.lastname: Hoque
authors.forename: Megumi
authors.initials: M
authors.lastname: Watanabe-Sugimoto
authors.forename: Ken
authors.initials: K
authors.lastname: Matsuoka
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: D000255:Adenosine Triphosphate / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism*; D001622:Betaine / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D011392:Proline / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects*; D014026:Nicotiana / Q000166:cytology* / Q000187:drug effects / Q000235:genetics / Q000276:immunology
chemical_list: D000975:Antioxidants; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D001622:Betaine; D012965:Sodium Chloride; D000255:Adenosine Triphosphate; D011392:Proline