title: Antisense-mediated suppression of tomato thylakoidal ascorbate peroxidase influences anti-oxidant network during chilling stress.
abstract: Photosynthesis is a well-established source of reactive oxygen species (ROS) in plants particularly under chilling stress. Ascorbate peroxidase (APXs) plays an important role in the anti-oxidant system by utilizing AsA as specific electron donor to reduce H(2)O(2) to water. In order to investigate the possible mechanisms of ascorbate peroxidsae (APX) in photoprotection under chilling stress, a tomato (Lycopersicon esculentum Mill.) thylakoidal ascorbate peroxidase gene (LetAPX) was isolated and antisense transgenic tomato plants were produced. Under chilling stress, transgenic plants accumulated more H(2)O(2), and showed higher levels of ion leakage and malondialdehyde (MDA), lower net photosynthetic rate (Pn), lower maximal photochemical efficiency of PSII (Fv/Fm) and less content of D1 protein compared with wild type (WT) plants. On the other hand, after chilling stress, transgenic plants showed higher reduced ascorbate (AsA) and activities of catalase (CAT) and superoxide dismutase (SOD) than those in WT plants, and the expression of several known stress-responsive and antioxidative genes was also higher at the end of chilling treatment. These results suggested that the suppression of LetAPX gene induced compensatory anti-oxidant mechanisms in tomato, and inactivation of tAPX may have a regulatory role in facilitating redox signaling pathways under chilling stress. Furthermore, transient increases in ROS levels also have a vital role in stress signaling and thereby in the survival of plants under chilling conditions.
authors: College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
authors: Ming
authors: M
authors: Duan
authors: Na-Na
authors: NN
authors: Ma
authors: Dong
authors: D
authors: Li
authors: Yong-Sheng
authors: YS
authors: Deng
authors: Fan-Ying
authors: FY
authors: Kong
authors: Wei
authors: W
authors: Lv
authors: Qing-Wei
authors: QW
authors: Meng
mesh_terms: D000222:Adaptation, Physiological; D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000235:genetics / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D003080:Cold Temperature; D016373:DNA, Antisense; D017343:Genes, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010788:Photosynthesis / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism; D030821:Plants, Genetically Modified; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism; D014867:Water / Q000378:metabolism
chemical_list: D000975:Antioxidants; D016373:DNA, Antisense; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D014867:Water; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D001205:Ascorbic Acid