title: Antisense-mediated depletion of tomato chloroplast glutathione reductase enhances susceptibility to chilling stress.
abstract: A tomato (Lycopersicon esculentum Mill.) chloroplast glutathione reductase gene (LeGR) was isolated and antisense transgenic tomato lines were obtained. Under chilling stress, transgenic plants accumulated more H(2)O(2), leaked more electrolyte and showed lower net photosynthetic rate (Pn), maximal photochemical efficiency of PSII (Fv/Fm) and oxidizable P700 compared with wild-type (WT) plants. Transgenic seedlings were more suppressed in fresh-weight growth and lost more cotyledon chlorophyll. The decrease in the activity of ascorbate peroxidase (APX) was implied to be potentially relevant to the greater accumulation of H(2)O(2) in transgenic plants. Chilling treatment induced more decrease in the level of reducted glutathione (GSH) and redox ratio of glutathione in transgenic plants than in WT plants, but aroused more increase in GSSG in transgenic plants than in WT plants. Total glutathione displayed no change. Besides, chilling stress resulted in greater decreases in the level of reducted ascorbate (AsA), total ascorbate and redox ratio of ascorbate in transgenic plants than in WT plants, but led to equivalent degree of dehydroascorbate (DHA) increase in WT and transgenic plants. These assessments of glutathione-ascorbate cycle revealed that the decrease of glutathione reductase activity in transgenic plants affected glutathione regeneration, and consequently affected ascorbate regeneration and total ascorbate content. This resulted in a greater accumulation of H(2)O(2) and an enhanced sensitivity to chilling stress in transgenic plants. Moreover, a putative concept model of ecophysiological reaction was discussed.
authors.affiliation: College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, PR China.
authors.forename: De-Feng
authors.initials: DF
authors.lastname: Shu
authors.forename: Li-Yan
authors.initials: LY
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Duan
authors.forename: Yong-Sheng
authors.initials: YS
authors.lastname: Deng
authors.forename: Qing-Wei
authors.initials: QW
authors.lastname: Meng
mesh_terms: D060054:Agrobacterium / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D060387:Ascorbate Peroxidases / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism; D015152:Blotting, Northern; D017796:Caulimovirus / Q000235:genetics / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis / Q000378:metabolism; D002736:Chloroplasts / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D003080:Cold Temperature; D016373:DNA, Antisense / Q000235:genetics / Q000378:metabolism; D005453:Fluorescence; D016166:Free Radical Scavengers / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010788:Photosynthesis; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011523:Protoplasts / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000302:isolation & purification; D017382:Reactive Oxygen Species / Q000378:metabolism; D016415:Sequence Alignment; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000378:metabolism; D014162:Transfection; D014170:Transformation, Genetic
chemical_list: D016373:DNA, Antisense; D016166:Free Radical Scavengers; D018749:RNA, Plant; D017382:Reactive Oxygen Species; D002734:Chlorophyll; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005978:Glutathione; D001205:Ascorbic Acid