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1.
NAC(NAM-ATAF1,2-CUC2)转录因子在植物胁迫响应中起重要作用。为了探讨三舭丹基因在番茄抗低温胁迫中的功能,分离了番茄LeNLP4转录因子基因,并获得转正义LeNLP4基因番茄植株。荧光定量PCR分析表明,LeNLP4的表达受低温诱导。与野生型植株相比,在4℃胁迫下转基因植株具有较高的生长量和光系统II(PSH)最大光化学效率(Fv/Fm)、过氧化氢(H2O2)和超氧阴离子(O2-)清除速率、抗坏血酸过氧化物酶(APX)和超氧化物歧化酶(SOD)活性,以及较低的丙二醛(MDA)含量和相对电导率(REC)。过表达株系中SICBF1的表达高于野生型。上述结果表明,LeNLP4的过表达提高了转基因番茄抗低温胁迫能力。 相似文献
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Feng Li Qing‐Yun Wu Yan‐Li Sun Li‐Yan Wang Xing‐Hong Yang Qing‐Wei Meng 《Physiologia plantarum》2010,139(4):421-434
A tomato (Lycopersicon esculentum Mill.) monodehydroascorbate reductase gene (LeMDAR) was isolated. The LeMDAR–green fluorescence protein (GFP) fusion protein was targeted to chloroplast in Arabidopsis mesophyll protoplast. RNA and protein gel blot analyses confirmed that the sense‐ and antisense‐ LeMDAR were integrated into the tomato genome. The MDAR activities and the levels of reduced ascorbate (AsA) were markedly increased in sense transgenic lines and decreased in antisense transgenic lines compared with wild‐type (WT) plants. Under low and high temperature stresses, the sense transgenic plants showed lower level of hydrogen peroxide (H2O2), lower thiobarbituric acid reactive substance (TBARS) content, higher net photosynthetic rate (Pn), higher maximal photochemical efficiency of PSII (Fv/Fm) and fresh weight compared with WT plants. The oxidizable P700 decreased more obviously in WT and antisense plants than that in sense plants at chilling temperature under low irradiance. Furthermore, the sense transgenic plants exhibited significantly lower H2O2 level, higher ascorbate peroxidase (APX) activity, greater Pn and Fv/Fm under methyl viologen (MV)‐mediated oxidative stresses. These results indicated that overexpression of chloroplastic MDAR played an important role in alleviating photoinhibition of PSI and PSII and enhancing the tolerance to various abiotic stresses by elevating AsA level. 相似文献
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Ascorbate peroxidase plays a key role in scavenging reactive oxygen species under environmental stresses and in protecting
plant cells against toxic effects. The Solanum lycopersicum thylakoid-bound ascorbate peroxidase gene (StAPX) was introduced into tobacco under the control of the cauliflower mosaic virus 35S promoter. Transformants were selected
for their ability to grow on medium containing kanamycin. RNA gel blot analysis confirmed that StAPX was transferred into the tobacco genome and StAPX was induced by salt and osmotic stresses in tomato leaves. Over-expression of StAPX in tobacco improved seed germination rate and elevated stress tolerance during post-germination development. Two transgenic
lines showed higher APX activity and accumulated less hydrogen peroxide than wild-type plants after stress treatments. The
photosynthetic rates, the root lengths, the fresh and dry weights of the transgenic lines were distinctly higher than those
of wild-type plants under stress conditions. Results indicated that the over-expression of StAPX had enhanced tolerance to salt stress and osmotic stress in transgenic tobacco plants. 相似文献
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Overexpression of bacterial catalase in tomato leaf chloroplasts enhances photo-oxidative stress tolerance 总被引:1,自引:0,他引:1
E.-A. MOHAMED T. IWAKI I. MUNIR M. TAMOI S. SHIGEOKA & A. WADANO 《Plant, cell & environment》2003,26(12):2037-2046
The Escherichia coli gene katE, which is driven by the promoter of the Rubisco small subunit gene of tomato, rbcS3C, was introduced into a tomato (Lycopersicon esculentum Mill.) by Agrobacterium tumefaciens‐mediated transformation. Catalase activity in progeny from transgenic plants was approximately three‐fold higher than that in wild‐type plants. Leaf discs from transgenic plants remained green at 24 h after treatment with 1 µm paraquat under moderate light intensity, whereas leaf discs from wild‐type plants showed severe bleaching after the same treatment. Moreover, ion leakage from transgenic leaf discs was significantly less than that from wild‐type leaf discs at 24 h after treatment with 1 µm paraquat and 10 mm H2O2, respectively, under moderate light intensity. To evaluate the efficiency of the E. coli catalase to protect the whole transgenic plant from the oxidative stress, transgenic and wild‐type plants were sprayed with 100 µm paraquat and exposed to high light illumination (800 µmol m?2 s?1). After 24 h, the leaves of the transgenic plants were less damaged than the leaves of the wild‐type plants. The catalase activity and the photosynthesis activity (indicated by the Fv/Fm ratio) were less affected by paraquat treatment in leaves of transgenic plants, whereas the activities of the chloroplastic ascorbate peroxidase isoenzymes and the ascorbate content decreased in both lines. In addition, the transgenic plants showed increased tolerance to the oxidative damage (decrease of the CO2 fixation and photosystem II activity and increase of the lipid peroxidation) caused by drought stress or chilling stress (4 °C) under high light intensity (1000 µmol m?2 s?1). These results indicate that the expression of the catalase in chloroplasts has a positive effect on the protection of the transgenic plants from the photo‐oxidative stress invoked by paraquat treatment, drought stress and chilling stress. 相似文献
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RNA gel hybridization showed that the expression of monodehydroascorbate reductase (MDHAR) in the wild type (WT) tomato was
decreased firstly and then increased under salt- and polyethylene glycol (PEG)-induced osmotic stress, and the maximum level
was observed after treatment for 12 h. WT, sense transgenic and antisense transgenic tomato plants were used to analyze the
antioxidative ability to cope with osmotic stresses. After salt stress, the fresh mass (FM) and height of sense transgenic
lines were greater than those of antisense lines and WT plants. Under salt and PEG treatments, sense transgenic plants showed
a lower level of hydrogen peroxide (H2O2) and malondialdehyde (MDA), a higher net photosynthetic rate (P
N), and the maximal photochemical efficiency of PSII (Fv/Fm) compared with WT and antisense transgenic plants. Moreover, sense lines maintained higher ascorbate peroxidase (APX) activity
than WT and antisense plants under salt- and PEG-induced osmotic stress. These results indicate that chloroplastic MDHAR plays
an important role in alleviating photoinhibition of PSII by elevating ascorbate (AsA) level under salt- and PEG-induced osmotic
stress. 相似文献
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Genetic engineering of the biosynthesis of glycinebetaine enhances thermotolerance of photosystem II in tobacco plants 总被引:1,自引:0,他引:1
Genetically engineered tobacco (Nicotiana tabacum L.) with the ability to accumulate glycinebetaine was established. The wild type and transgenic plants were exposed to heat
treatment (25–50°C) for 4 h in the dark and under growth light intensity (300 μmol m−2 s−1). The analyses of oxygen-evolving activity and chlorophyll fluorescence demonstrated that photosystem II (PSII) in transgenic
plants showed higher thermotolerance than in wild type plants in particular when heat stress was performed in the light, suggesting
that the accumulation of glycinebetaine leads to increased tolerance to heat-enhanced photoinhibition. This increased tolerance
was associated with an improvement on thermostability of the oxygen-evolving complex and the reaction center of PSII. The
enhanced tolerance was caused by acceleration of the repair of PSII from heat-enhanced photoinhibition. Under heat stress,
there was a significant accumulation of H2O2, O2− and catalytic Fe in wild type plants but this accumulation was much less in transgenic plants. Heat stress significantly
decreased the activities of catalase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monodehydroascorbate
reductase in wild type plants whereas the activities of these enzymes either decreased much less or maintained or even increased
in transgenic plants. In addition, heat stress increased the activity of superoxide dismutase in wild type plants but this
increase was much greater in transgenic plants. Furthermore, transgenic plants also showed higher content of ascorbate and
reduced glutathione than that of wild type plants under heat stress. The results suggest that the increased thermotolerance
induced by accumulation of glycinebetaine in vivo was associated with the enhancement of the repair of PSII from heat-enhanced
photo inhibition, which might be due to less accumulation of reactive oxygen species in transgenic plants. 相似文献
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Over-expression of chloroplastic glycerol-3-phosphate acyltransferase gene (LeGPAT) increased unsaturated fatty acid contents in phosphatidylglycerol (PG) of thylakoid membrane in tomato. The effect of this
increase on the xanthophyll cycle and chloroplast antioxidant enzymes was examined by comparing wild type (WT) tomato with
the transgenic (TG) lines at chilling temperature (4 °C) under low irradiance (100 μmol m−2 s−1). Net photosynthetic rate and the maximal photochemical efficiency of photosystem (PS) 2 (Fv/Fm) in TG plants decreased more slowly during chilling stress and Fv/Fm recovered faster than that in WT plants under optimal conditions. The oxidizable P700 in both WT and TG plants decreased
during chilling stress under low irradiance, but recovered faster in TG plants than in the WT ones. During chilling stress,
non-photochemical quenching (NPQ) and the de-epoxidized ratio of xanthophyll cycle in WT plants were lower than those of TG
tomatoes. The higher activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) in TG plants resulted in the
reduction of O2
−· and H2O2 contents during chilling stress. Hence the increase in content of unsaturated fatty acids in PG by the over-expression of
LeGPAT could alleviate photoinhibition of PS2 and PS1 by improving the de-epoxidized ratio of xanthophyll cycle and activities of
SOD and APX in chloroplast. 相似文献
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以野生型和过表达ZmSKIP基因烟草为试材, 研究了低温胁迫下过表达ZmSKIP对烟草抗氧化能力的影响。测定了不同低温处理时间下过表达ZmSKIP转基因烟草T3代植株和野生型植株抗氧化酶如超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性和丙二醛(MDA)含量以及相对电导率, 结果表明, 低温下, 相对于野生型植株, 转基因烟草具有较高的抗氧化酶活性和较低的相对电导率和MDA含量, 说明过表达ZmSKIP提高了转基因植株的耐低温胁迫能力。 相似文献
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A tomato (Lycopersicon esculentum Mill.) zeaxanthin epoxidase gene (LeZE) was isolated and antisense transgenic tomato plants were produced. Northern, southern, and western blot analyses demonstrated
that antisense LeZE was transferred into the tomato genome and the expression of LeZE was inhibited. The ratio of (A+Z)/(V+A+Z) in antisense transgenic plants was maintained at a higher level than in the wild
type (WT) plants under high light and chilling stress with low irradiance. The value of non-photochemical quenching (NPQ)
in WT and transgenic plants was not affected during the stresses. The oxidizable P700 and the maximal photochemical efficiency
of PSII (Fv/Fm) in transgenic plants decreased more slowly at chilling temperature under low irradiance. These results suggested that suppression
of LeZE caused zeaxanthin accumulation, which was helpful in alleviating photoinhibition of PSI and PSII in tomato plants under chilling
stress. 相似文献
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Transgenic cotton (Gossypium hirsutum L.) lines expressing the tobacco glutathione S-transferase (GST) Nt107 were evaluated for tolerance to chilling, salinity, and herbicides, antioxidant enzyme activity, antioxidant compound levels, and lipid peroxidation. Although transgenic seedlings exhibited ten-fold and five-fold higher GST activity under normal and salt-stress conditions, respectively, germinating seedlings did not show improved tolerance to salinity, chilling conditions, or herbicides. Glutathione peroxidase (GPX) activity in transgenic seedlings was 30% to 60% higher under normal conditions, but was not different than GPX activity in wild-type seedlings under salt-stress conditions. Glutathione reductase, superoxide dismutase, ascorbate peroxidase, and monodehydroascorbate reductase activities were not increased in transgenic seedlings under salt-stress conditions, while dehydroascorbate reductase activity was decreased in transgenic seedlings under salt-stress conditions. Transgenic seedlings had 50% more oxidized glutathione when exposed to salt stress. Ascorbate levels were not increased in transgenic seedlings under salt-stress conditions. Malondialdehyde content in transgenic seedlings was nearly double that of wild-type seedlings under normal conditions and did not increase under salt-stress conditions. These results show that expression of Nt107 in cotton does not provide adequate protection against oxidative stress and suggests that the endogenous antioxidant system in cotton may be disrupted by the expression of the tobacco GST. 相似文献
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This communication examines the role of small heat shock proteins (sHsps) targeted to mitochondria (Mt) and endoplasmic reticulum
(ER) in tomato plants (Lycopersicon esculentum Mill.) under heat stress. Genetic response of transgenic and wild type plants varied under optimum, moderately elevated and
elevated temperature. In optimum temperature higher biomass was recorded in wild type than the transgenic lines, whereas in
moderately elevated temperature biomass increased in Mt-sHsp line. Also, net photosynthetic rate (PN) increased in Mt-sHsp line in both the elevated temperatures, though higher in moderately elevated. Cell membrane stability
(CMS) improved in all the lines after exposure to elevated temperatures, but always remained higher in transgenic lines. Transgenic
lines expressed sHsps in different temperature regimes in both vegetative and reproductive parts, while wild type expressed
such proteins only after 1 h of heat shock. 相似文献
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Experiments were conducted to investigate the relationship between ultraviolet (UV) C-induced oxidative damage and the activity
of ascorbate peroxidase (APX), using transgenic tobacco (Nicotiana tabacum L. cv. Petit Havana) plants overexpressing cytosolic APX gene (apx1). Transgenic plants having 2.3 fold higher total APX activity, as compared to the wild type plants, showed normal morphological
characters. Exposure of 70-day-old plants to fixed intensity UV-C radiation caused an increase in the malondialdehyde (MDA)
content in wild type as well as transgenic plants. However, the wild type plants showed significantly higher (p < 0.05) lipid peroxidation as compared to the transgenic plants. Higher proline accumulation was recorded in transgenic plants
as compared to the wild type plants, after 24 hours of UV-C exposure. Although the ascorbate content decreased continuously
with increasing exposure to UV-C radiation, yet the wild type plants exhibited higher ascorbate levels than the transgenic
plants. A marked difference in H2O2 content, between the wild type and transgenic plants, was consistently observed up to 20 hours of UV-C exposure. A direct
correlation of ascorbate, MDA and H2O2 levels was recorded with the extent of oxidative stress, signifying that these could be used as potential bio-marker molecules
for oxidative stress. The results clearly demonstrate that overexpression of cytosolic APX can protect tobacco plants from
UV-C-induced oxidative damage. 相似文献
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W. -H. Sun X. -Y. Liu Y. Wang Q. Hua X. -M. Song Z. Gu D. -Z. Pu 《Biologia Plantarum》2014,58(1):99-104
We investigated the effect of water stress on yield and quality of tomato plants overexpressing Solanum lycopersicum thylakoid-bound ascorbate peroxidase gene (StAPX). APX activity, hydrogen peroxide content, net photosynthetic rate of tomato leaves, and yield and nutrition quality of tomato fruits were measured under soil moisture 70, 60, and 50 % of full field capacity. Results show that the capability of APX for scavenging hydrogen peroxide induced by water stress was higher in the transgenic than the wild type (WT) plants. The yield of fruits of the transgenic tomato plants was higher than that of WT plants under water stress and the fruit nutrition quality was not different. These results indicate that overexpression of StAPX might improve water stress tolerance in the transgenic tomato plants. 相似文献
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Shunhua Ding Qingtao Lu Yan Zhang Zhipan Yang Xiaogang Wen Lixin Zhang Congming Lu 《Plant molecular biology》2009,69(5):577-592
To investigate the possible mechanisms of glutathione reductase (GR) in protecting against oxidative stress, we obtained transgenic
tobacco (Nicotiana tabacum) plants with 30–70% decreased GR activity by using a gene encoding tobacco chloroplastic GR for the RNAi construct. We investigated
the responses of wild type and transgenic plants to oxidative stress induced by application of methyl viologen in vivo. Analyses
of CO2 assimilation, maximal efficiency of photosystem II photochemistry, leaf bleaching, and oxidative damage to lipids demonstrated
that transgenic plants exhibited enhanced sensitivity to oxidative stress. Under oxidative stress, there was a greater decrease
in reduced to oxidized glutathione ratio but a greater increase in reduced glutathione in transgenic plants than in wild type
plants. In addition, transgenic plants showed a greater decrease in reduced ascorbate and reduced to oxidized ascorbate ratio
than wild type plants. However, there were neither differences in the levels of NADP and NADPH and in the total foliar activities
of monodehydroascorbate reductase and dehydroascorbate reductase between wild type and transgenic plant. MV treatment induced
an increase in the activities of GR, ascorbate peroxidase, superoxide dismutase, and catalase. Furthermore, accumulation of
H2O2 in chloroplasts was observed in transgenic plants but not in wild type plants. Our results suggest that capacity for regeneration
of glutathione by GR plays an important role in protecting against oxidative stress by maintaining ascorbate pool and ascorbate
redox state. 相似文献
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Liyan Wang Xia Meng Dongyue Yang Nana Ma Guodong Wang Qingwei Meng 《Plant cell reports》2014,33(9):1441-1451