Modification of reactive oxygen species scavenging capacity of chloroplasts through plastid transformation
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Reactive oxygen species (ROS), including superoxide anions, hydrogen peroxide and hydroxyl radicals are generated through normal biochemical processes, but their production is increased by abiotic stresses. The prospects for enhancing ROS scavenging, and hence stress tolerance, by direct gene expression in a vulnerable cell compartment, the chloroplast, have been explored in tobacco. Several plastid transformants were generated which contained either a Nicotiana mitochondrial superoxide dismutase (MnSOD) or an Escherichia coli glutathione reductase (gor) gene. MnSOD lines had a three-fold increase in MnSOD activity, but interestingly a five to nine-fold increase in total chloroplast SOD activity. Gor transgenic lines had up to 6 times higher GR activity and up to 8 times total glutathione levels compared to wild type tobacco. Photosynthetic capacity of transplastomic plants, as measured by chlorophyll content and variable fluorescence of PSII was equivalent to non-transformed plants. The response of these transplastomic lines to several applied stresses was examined. In a number of cases improved stress tolerance was observed. Examples include enhanced methyl viologen (Paraquat)-induced oxidative stress tolerance in Mn-superoxidase dismutase over-expressing plants, improved heavy metal tolerance in glutathione reductase expressing lines, and improved tolerance to UV-B radiation in both sets of plants.
KeywordsChloroplast transformation Superoxide dismutase Glutathione reductase Abiotic stress
This research was supported by grants from Science Foundation Ireland (grant: 06/RFP/EEB035) and Enterprise Ireland (grant: SC/2001/343). The authors would like to thank Manfred Klaas and Olga Grant for assistance in the preparation of the figures.
- Aono M, Kubo A, Saji H, Tanaka K, Kondo N (1993) Enhanced tolerance to photooxidative stress of transgenic Nicotiana tabacum with high chloroplastic glutathione reductase activity. Plant Cell Physiol 34:129–135Google Scholar
- Arisi A-CM, Cornic G, Jouanin L, Foyer CH (1998) Overexpression of iron superoxide dismutase in transformed poplar modifies the regulation of photosynthesis at low CO2 partial pressures or following exposure to the prooxidant herbicide methyl viologen. Plant Physiol 117:565–574PubMedCrossRefGoogle Scholar
- Chen C-N, Pan S-M (1996) Assay of superoxide dismutase activity by combining electrophoresis and densitometry. Bot Bull Acad Sin 37:107–111Google Scholar
- Creissen G, Firmin J, Fryer M, Kular B, Leyland N, Reynolds H, Pastori G, Wellburn F, Baker N, Wellburn A, Mullineaux P (1999) Elevated glutathione biosynthetic capacity in the chloroplasts of transgenic tobacco plants paradoxically causes increased oxidative stress. Plant Cell 11:1277–1291PubMedCrossRefGoogle Scholar
- Foyer CH, Souriau N, Perret S, Lelandais M, Kunert KJ, Pruvost C, Jouanin L (1995) Overexpression of glutathione reductase but not glutathione synthase leads to increases in antioxidant capacity and resistance to photoinhibition in poplar trees. Plant Physiol 109:1047–1057PubMedCrossRefGoogle Scholar
- Heggie L, Jansen MAK, Burbridge EM, Kavanagh TA, Thorneley RNF, Dix PJ (2005) Transgenic tobacco (Nicotiana tabacum L. cv. Samsun-NN) plants over-expressing a synthetic HRP-C gene are altered in growth, development and susceptibility to abiotic stress. Plant Physiol Biochem 43:1067–1073PubMedCrossRefGoogle Scholar
- Le Martret B, Poage M, Shiel K, Nugent GD, Dix PJ (2011) Tobacco chloroplast transformants expressing genes encoding dehydroascorbate reductase, glutathione reductase, and glutathione-S-transferase, exhibit altered anti-oxidant metabolism and improved abiotic stress tolerance. Plant Biotechnol J (in press)Google Scholar
- Lee SH, Ahsan N, Lee KW, Kim DH, Lee DG, Kwak SS, Kwon SY, Kim TH, Lee BH (2007a) Simultaneous overexpression of both CuZn superoxide dismutase and ascorbate peroxidase in transgenic tall fescue plants confers increased tolerance to a wide range of abiotic stresses. J Plant Physiol 164:1626–1638PubMedCrossRefGoogle Scholar
- Sambrook J, Fritsch E, Maniatis T (eds) (1989) Molecular cloning: a laboratory manual, 2nd edn. Cold Spring Harbor Laboratory, Cold Spring HarborGoogle Scholar
- Slesak I, Karpinska B, Surówka E, Miszalski Z, Karpinski S (2003) Redox changes in the chloroplast and hydrogen peroxide are essential for regulation of C3—CAM transition and photooxidative stress responses in the facultative CAM plant Mesembryanthemum crystallinum L. Plant Cell Physiol 44:573–581PubMedCrossRefGoogle Scholar
- Tang L, Kwon SY, KimSH KimJS, Choi JS, Cho KY, Sung CK, Kwak SS, Lee HS (2006) Enhanced tolerance of transgenic potato plants expressing both superoxide dismutase and ascorbate peroxidase in chloroplasts against oxidative stress and high temperature. Plant Cell Rep 25:1380–1386PubMedCrossRefGoogle Scholar