Enhanced tolerance to methyl viologen-induced oxidative stress and high temperature in transgenic potato plants overexpressing the CuZnSOD, APX and NDPK2 genes.
Oxidative stress is a major threat for plants exposed to various environmental stresses. Previous studies found that transgenic potato plants expressing both copper zinc superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) (referred to as SSA plants), or nucleoside diphosphate kinase 2 (NDPK2) (SN plants), showed enhanced tolerance to methyl viologen (MV)-induced oxidative stress and high temperature. This study aimed to develop transgenic plants that were more tolerant of oxidative stress by introducing the NDPK2 gene into SSA potato plants under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter to create SSAN plants. SSAN leaf discs and whole plants showed enhanced tolerance to MV, as compared to SSA, SN or non-transgenic (NT) plants. SSAN plants sprayed with 400 µM MV exhibited about 53 and 83% less visible damage than did SSA and SN plants, respectively. The expression levels of the CuZnSOD, APX and NDPK2 genes in SSAN plants following MV treatment correlated well with MV tolerance. SOD, APX, NDPK and catalase antioxidant enzyme activities were also increased in MV-treated SSAN plants. In addition, SSAN plants were more tolerant to high temperature stress at 42°C, exhibiting a 6.2% reduction in photosynthetic activity as compared to plants grown at 25°C. In contrast, the photosynthetic activities of SN and SSA plants decreased by 50 and 18%, respectively. These results indicate that the simultaneous overexpression of CuZnSOD, APX and NDPK2 is more effective than single or double transgene expression for developing plants with enhanced tolerance to various environmental stresses.
Kim
Myoung Duck
MD
Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.
Kim
Yun-Hee
YH
Kwon
Suk-Yoon
SY
Yun
Dae-Jin
DJ
Kwak
Sang-Soo
SS
Lee
Haeng-Soon
HS
D000222:Adaptation, Physiological / Q000235:genetics; D060387:Ascorbate Peroxidases; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006540:Herbicides / Q000494:pharmacology; D009701:Nucleoside-Diphosphate Kinase / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects*; D010269:Paraquat / Q000494:pharmacology*; D010544:Peroxidases / Q000235:genetics; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D011198:Solanum tuberosum / Q000235:genetics*; D013482:Superoxide Dismutase / Q000235:genetics; D013696:Temperature; D019076:Transgenes / Q000235:genetics*
D006540:Herbicides; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase; C121988:nucleoside diphosphate kinase 2; D009701:Nucleoside-Diphosphate Kinase; D010269:Paraquat