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Plant Cell Reports

, Volume 26, Issue 5, pp 591–598

First Online: 01 February 2007Received: 28 July 2006Revised: 11 September 2006Accepted: 17 September 2006

Abstract

The effect of simultaneous expression of genes encoding three antioxidant enzymes, copper zinc superoxide dismutase CuZnSOD, EC 1.15.1.1, ascorbate peroxidase APX, EC 1.11.1.11, and dehydroascorbate DHA reductase DHAR, EC 1.8.5.1, in the chloroplasts of tobacco plants was investigated under oxidative stress conditions. In previous studies, transgenic tobacco plants expressing both CuZnSOD and APX in chloroplast CA plants, or DHAR in chloroplast showed enhanced tolerance to oxidative stresses, such as paraquat and salt. In this study, in order to develop transgenic plants that were more resistant to oxidative stress, we introduced the gene encoding DHAR into CA transgenic plants. Mature leaves of transgenic plants expressing all three antioxidant genes CAD plants had approximately 1.6–2.1 times higher DHAR activity, and higher ratios of reduced ascorbate AsA to DHA, and oxidized glutathione GSSG to reduced glutathione GSH compared to CA plants. CAD plants were more resistant to paraquat-induced stress, exhibiting only 18.1% reduction in membrane damage relative to CA plants. In addition, seedlings of CAD plants had enhanced tolerance to NaCI 100 mM compared to CA plants. These results indicate that the simultaneous expression of multiple antioxidant enzymes, such as CuZnSOD, APX, and DHAR, in chloroplasts is more effective than single or double expression for developing transgenic plants with enhanced tolerance to multiple environmental stresses.

KeywordsAscorbate Ascorbate peroxidase Chloroplast Dehydroascorbate reductase Glutathione Methyl viologen Oxidative stress Superoxide dismutase Communicated by J. R. Liu

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Author: Young-Pyo Lee - Sun-Hyung Kim - Jae-Wook Bang - Haeng-Soon Lee - Sang-Soo Kwak - Suk-Yoon Kwon

Source: https://link.springer.com/







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