JOURNAL OF APPLIED HORTICULTURE Vol. 9, No. 1, January-June, 2007 (original) (raw)
Related papers
2007
Production of reactive oxygen species (ROS) is associated with a number of physiological disorders in plants. Superoxide dismutase (SOD) catalyzes the breakdown of superoxide (O 2 -) into O 2 and H 2 O 2 and provides the rst line of defense against the toxic effects of elevated levels of ROS. The effect of increased expression of Mn superoxide dismutase (Mn-SOD) on salt stress tolerance was studied using transformed tomato (Lycopersicon esculentum cv. Zhongshu No. 5) plants. Northern blots con rmed expression of the heterologous Mn-SOD in transgenic plants. Strong Mn-SOD enzyme activity was detected by native PAGE in transformed plants.
Plant Cell Reports, 2006
Oxidative stress is a major damaging factor for plants exposed to environmental stresses. In order to develop transgenic potato plants with enhanced tolerance to environmental stress, the genes of both Cu/Zn superoxide dismutase and ascorbate peroxidase were expressed in chloroplasts under the control of an oxidative stressinducible SWPA2 promoter (referred to as SSA plants). SSA plants showed enhanced tolerance to 250 µM methyl viologen, and visible damage in SSA plants was one-fourth that of non-transgenic (NT) plants that were almost destroyed. In addition, when SSA plants were treated with a high temperature of 42 • C for 20 h, the photosynthetic activity of SSA plants decreased by only 6%, whereas that of NT plants decreased by 29%. These results suggest that the manipulation of the antioxidative mechanism of the chloroplasts may be applied in the development of Communicated by I. S. Chung industrial transgenic crop plants with increased tolerance to multiple environmental stresses.
Enhanced oxidative-stress defense in transgenic potato expressing tomato Cu,Zn superoxide dismutases
Theoretical and Applied Genetics, 1993
The two cDNAs coding for the cytosolic (cyt) and the chloroplast-located (chl) Cu,Zn superoxide dismutases (SODs) of tomato (Perl-Treves et al. 1988) were cloned into respective binary vectors and mobilized into Agrobacterium strains. Potato tuber discs were infected with either of the two agrobacterial strains and cultured on selective medium containing kanaymcin. The integration of either of the cyt or the chl SOD transgenes was verified by Southern-blot hybridization. The enzymatic activity of the additional tomato chl Cu,Zn SOD could be distinguished from endogenous SOD activity since the latter isozyme migrated faster on SOD-activity gels. Several transgenic potato lines harboring either the cyt or the chl SOD genes of tomato showed elevated tolerance to the superoxide-generating herbicide paraquat (methyl viologen). After exposure of shoots to paraquat, tolerance was recorded either by scoring symptoms visually or by measurements of photosynthesis using the photoacoustic method. Root cultures from transgenic lines that harbored the additional cyt Cu,Zn SOD gene of tomato were tolerant to methyl viologen up to 10-s M; a lower tolerance was recorded in roots of transgenic lines that expressed the additional chl Cu,Zn SOD of tomato.
The EMBO journal, 1991
In plants, environmental adversity often leads to the formation of highly reactive oxygen radicals. Since resistance to such conditions may be correlated with the activity of enzymes involved in oxygen detoxification, we have generated transgenic tobacco plants which express elevated levels of manganese superoxide dismutase (MnSOD) within their chloroplasts or mitochondria. Leaf discs of these plants have been analyzed in conditions in which oxidative stress was generated preferentially within one or the other organelle. It was found that high level overproduction of MnSOD in the corresponding subcellular location could significantly reduce the amount of cellular damage which would normally occur. In contrast, small increases in MnSOD activity were deleterious under some conditions. A generally applicable model correlating the consequences of SOD with the magnitude of its expression is presented.
Superoxide dismutase and stress tolerance of four tomato cultivars
Hortscience, 2004
Additional index words. Lycopersicon esculentum Mill., tomato, cultivar, water stress, leaf water potential Abstract. Effects of water stress on superoxide dismutase (SOD) activities, changes in protein content, leaf water potential (Ψ l ) and growth were studied in drought-sensitive Kyokko (KK) and Ratan (RT), and drought-tolerant TM 0126 (TM) and VF-134-1-2 (VF) cultivars of tomato (Lycopersicon esculentum Mill.) in order to obtain fundamental information for breeding drought tolerant cultivars that may be adapted to water stress in many parts of the world. Growth of drought-tolerant TM and VF was greater than that of droughtsensitive KK and RT under water stress conditions. Leaf water potential (Ψ l ) decreased by water stress treatments in all the cultivars, but the reduction was much more rapid and pronounced in KK and RT than VF and TM. Ψ l of stressed cultivars decreased by 30% to 40% compared to the untreated control cultivars. The initial reduction in the range of 20% to 35% was more rapid in KK and RT than TM and VF. SOD activities were increased by water stress in all cultivars. Increase of SOD activities by water stress was much more rapid and pronounced in TM and VF than in KK and RT. Leaf protein concentration was decreased by the water stress treatments in all cultivars evaluated. In KK and RT, much more rapid reductions in protein concentration were observed than in TM and VF. The regression analysis of Ψ l and SOD suggest the possibility to using SOD activities as an additional screening criterion for tomato drought tolerance improvement.
Transgenic Arabidopsis overexpressing Mn-SOD enhanced salt-tolerance
Plant Science, 2004
The Mn-SOD is a critical enzyme eliminating reactive oxygen species (ROS) in plant cells under environmental stresses, but the roles of Mn-SOD in plant cells under salt stress remains elusive. This study focuses on the effects of Mn-SOD overexpressed in transgenic Arabidopsis on salt tolerance. We have constructed the transgenic Arabidopsis overexpressing Mn-SOD, the activity of which was more than two-fold over that of wild type. When treated with 150 mM NaCl, the transgenic plants grew well, while the wild type plants withered gradually, this indicated the transgenic Arabidopsis enhanced salt-tolerance. Further analyses showed that not only the activities of Mn-SOD but also the activities of other antioxidative enzymes such as Cu/Zn-SOD, Fe-SOD, catalase (CAT) and peroxidase (POD) of transgenic plants treated by 150 mM NaCl were markedly higher than those of wild type plants, and the contents of malondialdehyde (MDA) were lower than those of wild type under 150 mmol/L NaCl treatment, indicating the ability of eliminating ROS in transgenic Arabidopsis increased significantly. These results suggested that the Mn-SOD overexpressed in Arabidopsis played a pivotal role in preventing the over accumulation of ROS and protecting the cells against ROS caused by salt stress, as a result, enhanced salt-tolerance of the transgenic plants. This study will help explain the essential roles of Mn-SOD in adaptive responses of plant cells under environmental stresses.
Plant physiology, 1993
Photosynthesis of leaf discs from transgenic tobacco plants (Nicotiana tabacum) that express a chimeric gene that encodes chloroplast-localized Cu/Zn superoxide dismutase (SOD+) was protected from oxidative stress caused by exposure to high light intensity and low temperature. Under the same conditions, leaf discs of plants that did not express the pea SOD isoform (SOD-) had substantially lower photosynthetic rates. Young plants of both genotypes were more sensitive to oxidative stress than mature plants, but SOD+ plants retained higher photosynthetic rates than SOD- plants at all developmental stages tested. Not surprisingly, SOD+ plants had approximately 3-fold higher SOD specific activity than SOD- plants. However, SOD+ plants also exhibited a 3- to 4-fold increase in ascorbate peroxidase (APX) specific activity and had a corresponding increase in levels of APX mRNA. Dehydroascorbate reductase and glutathione reductase specific activities were the same in both SOD+ and SOD- plant...
Plant Science, 2004
A chimeric gene consisting of the coding sequence for cytosolic Cu/Zn-superoxide dismutases (SOD) from Oryza sativa fused to the chloroplast transit sequence from Arabidopsis thaliana glutathione reductase was used for generating transgenic tobacco plants. This construct was cloned into appropriate binary vector and mobilized into Agrobacterium tumefaciens C58C2. Tobacco leaf discs were infected with Agrobacterium and cultured on kanamycin selective medium. The integration and expression of Cu/Zn-SOD in tobacco genome was confirmed by Southern dot blot hybridization and SOD activity staining, respectively. Several transgenic lines were obtained and screened for SOD activity. The transgenic lines showed enhanced tolerance to the active oxygen-generating paraquat and sodium sulfite. Similarly, when net photosynthesis was measured, the first generation of the transgenic lines showed enhanced tolerance to salt, water, and PEG stresses, over the wild type. These results suggested that the overexpressed Cu/Zn-SOD enhances the chloroplast antioxidant system.