title: Synergistic effects of GhSOD1 and GhCAT1 overexpression in cotton chloroplasts on enhancing tolerance to methyl viologen and salt stresses.
abstract: In plants, CuZn superoxide dismutase (CuZnSOD, EC l.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), and catalase (CAT, EC l.11.1.6) are important scavengers of reactive oxygen species (ROS) to protect the cell from damage. In the present study, we isolated three homologous genes (GhSOD1, GhAPX1, and GhCAT1) from Gossypium hirsutum. Overexpressing cassettes containing chimeric GhSOD1, GhAPX1, or GhCAT1 were introduced into cotton plants by Agrobacterium transformation, and overexpressed products of these genes were transported into the chloroplasts by transit peptide, as expected. The five types of transgenic cotton plants that overexpressed GhSOD1, GhAPX1, GhCAT1, GhSOD1 and GhAPX1 stack (SAT), and GhSOD1 and GhCAT1 stack (SCT) were developed. Analyses in the greenhouse showed that the transgenic plants had higher tolerance to methyl viologen (MV) and salinity than WT plants. Interestingly, SCT plants suffered no damage under stress conditions. Based on analyses of enzyme activities, electrolyte leakage, chlorophyll content, photochemical yield (Fv/Fm), and biomass accumulation under stresses, the SCT plants that simultaneously overexpressed GhSOD1 and GhCAT1 appeared to benefit from synergistic effects of two genes and exhibited the highest tolerance to MV and salt stress among the transgenic lines, while the SAT plants simultaneously overexpressing GhSOD1 and GhAPX1 did not. In addition, transgenic plants overexpressing antioxidant enzymes in their chloroplasts had higher tolerance to salt stress than those expressing the genes in their cytoplasms, although overall enzyme activities were almost the same. Therefore, the synergistic effects of GhSOD1 and GhCAT1 in chloroplasts provide a new strategy for enhancing stress tolerance to avoid yield loss.
authors: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors: Xiaoli
authors: X
authors: Luo
authors: Jiahe
authors: J
authors: Wu
authors: Yuanbao
authors: Y
authors: Li
authors: Zhirun
authors: Z
authors: Nan
authors: Xing
authors: X
authors: Guo
authors: Yixue
authors: Y
authors: Wang
authors: Anhong
authors: A
authors: Zhang
authors: Zhian
authors: Z
authors: Wang
authors: Guixian
authors: G
authors: Xia
authors: Yingchuan
authors: Y
authors: Tian
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D060387:Ascorbate Peroxidases / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics* / Q000378:metabolism; D004789:Enzyme Activation / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D023061:Gene Order; D003368:Gossypium / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress; D010641:Phenotype; D030821:Plants, Genetically Modified; D055049:Salt Tolerance / Q000235:genetics; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism; D000072105:Superoxide Dismutase-1
chemical_list: D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1