title: Glucose-6-phosphate dehydrogenase and alternative oxidase are involved in the cross tolerance of highland barley to salt stress and UV-B radiation.
abstract: In this study, a new mechanism involving glucose-6-phosphate dehydrogenase (G6PDH) and alternative pathways (AP) in salt pretreatment-induced tolerance of highland barley to UV-B radiation was investigated. When highland barley was exposed to UV-B radiation, the G6PDH activity decreased but the AP capacity increased. In contrast, under UV-B+NaCl treatment, the G6PDH activity was restored to the control level and the maximal AP capacity and antioxidant enzyme activities were reached. Glucosamine (Glucm, an inhibitor of G6PDH) obviously inhibited the G6PDH activity in highland barley under UV-B + NaCl treatment and a similar pattern was observed in reduced glutathione (GSH) and ascorbic acid (Asc) contents. Similarly, salicylhydroxamic acid (SHAM, an inhibitor of AOX) significantly reduced the AP capacity in highland barley under UV-B + NaCl treatment. The UV-B-induced hydrogen peroxide (H2O2) accumulation was also followed. Further studies indicated that non-functioning of G6PDH or AP under UV-B+NaCl + Glucm or UV-B + NaCl + SHAM treatment also caused damages in photosynthesis and stomatal movement. Western blot analysis confirmed that the alternative oxidase (AOX) and G6PDH were dependent each other in cross tolerance to UV-B and salt. The inhibition of AP or G6PDH activity resulted in a significant accumulation or reduction of NADPH content, respectively, under UV-B+NaCl treatment in highland barley leaves. Taken together, our results indicate that AP and G6PDH mutually regulate and maintain photosynthesis and stomata movement in the cross adaptation of highland barley seedlings to UV-B and salt by modulating redox homeostasis and NADPH content.
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
authors.forename: Chengzhou
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China. Electronic address: wangxiaomin@lzu.edu.cn.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Wang
authors.affiliation: Qinghai Academy of Agricultural and Forestry Sciences, People's Republic of China.
authors.forename: Kunlun
authors.initials: K
authors.lastname: Wu
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
authors.forename: Ning
authors.initials: N
authors.lastname: Chang
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
authors.forename: Jiaolong
authors.initials: J
authors.lastname: Li
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China. Electronic address: yrbi@lzu.edu.cn.
authors.forename: Yurong
authors.initials: Y
authors.lastname: Bi
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects* / Q000528:radiation effects; D000975:Antioxidants / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism; D015153:Blotting, Western; D019069:Cell Respiration / Q000187:drug effects / Q000528:radiation effects; D002734:Chlorophyll / Q000378:metabolism; D005453:Fluorescence; D005944:Glucosamine / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D001467:Hordeum / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology* / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D010088:Oxidoreductases / Q000378:metabolism*; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects; D010940:Plant Proteins / Q000378:metabolism*; D054046:Plant Stomata / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure; D011188:Potassium / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects* / Q000528:radiation effects; D014466:Ultraviolet Rays; D000099188:Alternative Oxidase
chemical_list: D000975:Antioxidants; D001205:Ascorbic Acid; D002734:Chlorophyll; D005944:Glucosamine; D005954:Glucosephosphate Dehydrogenase; D005978:Glutathione; D006861:Hydrogen Peroxide; D024101:Mitochondrial Proteins; D009249:NADP; D010088:Oxidoreductases; D010940:Plant Proteins; D011188:Potassium; D012964:Sodium; D012965:Sodium Chloride; D000099188:Alternative Oxidase
keywords: Alternative pathway; Cross-tolerance; Glucose-6-phosphate dehydrogenase; Highland barley; Oxidative stress