Enhanced stress-tolerance of transgenic tobacco plants expressing a human dehydroascorbate reductase gene

• Published in: Journal of plant physiology Vol. 160; no. 4; pp. 347 - 353
• Main Authors: Kwon, Suk-Yoon, Choi, Sun-Mee, Ahn, Young-Ock, Lee, Haeng-Soon, Lee, Hae-Bok, Park, Yong-Mok, Kwak, Sang-Soo
• Format: Journal Article
• Language: English
• Published: Jena Elsevier GmbH 01.04.2003; Elsevier; Elsevier Science Ltd
• Subjects: Adaptation to environment and cultivation conditions; Adaptation, Physiological; Agronomy. Soil science and plant productions; ascorbic acid; Biological and medical sciences; Cold Temperature; dehydroascorbate reductase; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; glutathione; Humans; Hydrogen Peroxide - pharmacology; Metabolism; Metabolism. Physicochemical requirements; methyl viologen; Nicotiana - genetics; Nicotiana - metabolism; Nicotiana - physiology; Nicotiana tabacum; oxidative stress; Oxidoreductases - genetics; Paraquat - pharmacology; Plant Leaves - drug effects; Plant physiology and development; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Plants, Genetically Modified - physiology; Sodium Chloride - administration & dosage; transgenic tobacco plant; Varietal selection. Specialized plant breeding, plant breeding aims; ascorbic acid; transgenic tobacco plant; methyl viologen; glutathione; dehydroascorbate reductase; oxidative stress; Glutathione dehydrogenase (ascorbate); Enzyme; Tolerance; Antioxidant; Gene expression; Nicotiana tabacum; Stress; Dicotyledones; Angiospermae; Spermatophyta; Transgenic plant; Oxidoreductases; Solanaceae
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1078/0176-1617-00926

To analyze the physiological role of dehydroascorbate reductase (DHAR, EC 1.8.5.1) catalyzing the reduction of DHA to ascorbate in environmental stress adaptation, T 1 transgenic tobacco ( Nicotiana tabacum cv. Xanthi) plants expressing a human DHAR gene in chloroplasts were biochemically characterized and tested for responses to various stresses. Fully expanded leaves of transgenic plants had about 2.29 times higher DHAR activity (units/g fresh wt) than non-transgenic (NT) plants. Interestingly, transgenic plants also showed a 1.43 times higher glutathione reductase activity than NT plants. As a result, the ratio of AsA/DHA was changed from 0.21 to 0.48, even though total ascorbate content was not significantly changed. When tobacco leaf discs were subjected to methyl viologen (MV) at 5 μmol/L and hydrogen peroxide (H 2O 2) at 200 mmol/L, transgenic plants showed about a 40 percnt; and 25 percnt; reduction in membrane damage relative to NT plants, respectively. Furthermore, transgenic seedlings showed enhanced tolerance to low temperature (15 °C) and NaCl (100 mmol/L) compared to NT plants. These results suggest that a human derived DHAR properly works for the protection against oxidative stress in plants.