title: Overexpression of CuZnSOD from Arachis hypogaea alleviates salinity and drought stress in tobacco.
abstract: Overexpression of CuZnSOD gene from Arachis hypogaea demonstrating its involvement in abiotic stress tolerance. Abiotic stress is accompanied by the formation of reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, and hydroxyl radicals, causing extensive cellular damage and inhibition of photosynthesis that limit the plant productivity. The level of ROS in cells needs to be tightly regulated and the toxic effects of ROS are countered by enzymatic as well as non-enzymatic antioxidant systems. The superoxide dismutase is the first enzyme involved in the detoxification of ROS and converts superoxide (O2(·-)) radicals to H2O2. A full-length cDNA clone encoding a CuZnSOD, named AhCuZnSOD, was isolated from the salt tolerant cell lines of Arachis hypogaea, stably thriving at 200 mM NaCl. The cell line showed higher transcript accumulation under multiple abiotic stresses, including drought, salinity, cold and oxidative stress treatment. The functional role of AhCuZnSOD in alleviation of abiotic stress was assessed by its overexpression in transgenic tobacco plants. The T1 transgenic plants showed improved tolerance to salinity and dehydration stress as indicated by higher seed germination and better chlorophyll content. The transgenic plants survived under longer periods of water deficiency and salinity stress and displayed improved recovery after rehydration compared to the wild type (WT) plants. The enhanced level of the transgene correlated with higher relative water content, less electrolyte damage, less malondialdehyde, higher antioxidant enzyme activity, H2O2 and O2(·-) accumulation under stress conditions compared to WT plants. Our results substantiate that increased levels of SOD activity brought about by overexpression of AhCuZnSOD gene may play an important role in ameliorating oxidative injury induced by various environmental stresses.
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
authors.forename: Neelam Prabha
authors.initials: NP
authors.lastname: Negi
authors.forename: Divya Chavhan
authors.initials: DC
authors.lastname: Shrivastava
authors.forename: Vinay
authors.initials: V
authors.lastname: Sharma
authors.forename: Neera Bhalla
authors.initials: NB
authors.lastname: Sarin
mesh_terms: D000595:Amino Acid Sequence; D000975:Antioxidants / Q000378:metabolism; D010367:Arachis / Q000201:enzymology*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D055864:Droughts; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D008969:Molecular Sequence Data; D010788:Photosynthesis / Q000187:drug effects; D010802:Phylogeny; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D030821:Plants, Genetically Modified; D011392:Proline / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012038:Regeneration / Q000187:drug effects; D054712:Salinity; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D016415:Sequence Alignment; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D014170:Transformation, Genetic / Q000187:drug effects; D014867:Water / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D014867:Water; D002734:Chlorophyll; D012965:Sodium Chloride; D008315:Malondialdehyde; D011392:Proline; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase