共查询到20条相似文献,搜索用时 78 毫秒
1.
In order to investigate the function of chloroplast ascorbate peroxidase under temperature stress, the thylakoid-bound ascorbate
peroxidase gene from tomato leaf (TtAPX) was introduced into tobacco. Transformants were selected for their ability to grow on medium containing kanamycin. RNA gel
blot analysis confirmed that TtAPX in tomato was induced by chilling or heat stress. Over-expression of TtAPX in tobacco improved seed germination under temperature stress. Two transgenic tobacco lines showed higher ascorbate peroxidase
activity, accumulated less hydrogen peroxide and malondialdehyde than wild type plants under stress condition. The photochemical
efficiency of photosystem 2 in the transgenic lines was distinctly higher than that of wild type plants under chilling and
heat stresses. Results indicated that the over-expression of TtAPX enhanced tolerance to temperature stress in transgenic tobacco plants. 相似文献
2.
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
3.
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
4.
Cytokinin-induced activity of antioxidant enzymes in transgenic Pssu-ipt tobacco during plant ontogeny 总被引:1,自引:0,他引:1
H. Synkova S. Semoradova R. Schnablova E. Witters M. Husak R. Valcke 《Biologia Plantarum》2006,50(1):31-41
Cytokinin (CK) content and activities of several antioxidant enzymes were examined during plant ontogeny with the aim to elucidate
their role in delayed senescence of transgenic Pssu-ipt tobacco. Control Nicotiana tabacum L. (cv. Petit Havana SR1) and transgenic tobacco with the ipt gene under the control of the promoter of small subunit of Rubisco (Pssu-ipt) were both grown either as grafts on control rootstocks or as rooted plants. Both control plant types showed a decline in
total content of CKs with proceeding plant senescence. Contrary to this both transgenic plant types exhibited at least ten
times higher content of CKs than controls and a significant increase of CK contents throughout the ontogeny with maximal values
in the later stages of plant development. Significantly higher portion of O-glucosides was found in both transgenic plant types compared to control ones. In transgenic plants, zeatin and zeatin riboside
were predominant type of CKs. Generally, Pssu-ipt tobacco exhibited elevated activities of antioxidant enzymes compared to control tobacco particularly in the later stages
of plant development. While in control tobacco activity of glutathione reductase (GR) and superoxide dismutase (SOD) showed
increasing activity up to the onset of flowering and then gradually decreased, in both transgenic types GR increased and SOD
activity showed only small change throughout the plant ontogeny. Ascorbate peroxidase (APOD) was stimulated in both transgenic
types. The manifold enhancement of syringaldazine and guaiacol peroxidase activities was observed in transgenic grafts throughout
plant ontogeny in contrast to control and transgenic rooted plants, where the increase was found only in the late stages.
Electron microscopic examination showed higher number of crystallic cores in peroxisomes and abnormal interactions among organelles
in transgenic tobacco in comparison with control plant. The overproduction of cytokinins resulted in the stimulation of activities
of AOE throughout the plant ontogeny of transgenic Pssu-ipt tobacco. 相似文献
5.
The Saccharomyces cerevisiae chitinase,encoded by the CTS1-2 gene,confers antifungal activity against Botrytis cinerea to Transgenic tobacco 总被引:2,自引:0,他引:2
The Saccharomyces cerevisiae chitinase, encoded by the CTS1-2 gene has recently been confirmed by in vitro tests to possess antifungal abilities. In this study, the CTS1-2 gene has been evaluated for its in planta antifungal activity by constitutive overexpression in tobacco plants to assess its potential to increase the plant's defence against fungal pathogens. Transgenic tobacco plants, generated by Agrobacterium-mediated transformation, showed stable integration and inheritance of the transgene. Northern blot analyses conducted on the transgenic tobacco plants confirmed transgene expression. Leaf extracts from the transgenic lines inhibited Botrytis cinerea spore germination and hyphal growth by up to 70% in a quantitative in vitro assay, leading to severe physical damage on the hyphae. Several of the F1 progeny lines were challenged with the fungal pathogen, B. cinerea, in a detached leaf infection assay, showing a decrease in susceptibility ranging from 50 to 70%. The plant lines that showed increased disease tolerance were also shown to have higher chitinase activities. 相似文献
6.
7.
Down-regulation of an anionic peroxidase in transgenic aspen and its effect on lignin characteristics 总被引:9,自引:0,他引:9
It is generally accepted that peroxidases catalyze the final step in the biosynthesis of lignin. In this study, to examine
how expression of prxA3a, a gene for an anionic peroxidase, might be related to lignification in plant tissues, we produced transgenic tobacco plants
that harbored a gene for β-glucuronidase (GUS) fused to the prxA3a promoter. Histochemical staining for GUS activity indicated that the prxA3a promoter was active mainly in the lignifying cells of stem tissues. Further, to examine the effects of suppressing the expression
of prxA3a, we transferred an antisense prxA3a gene construct into the original host, hybrid aspen (Populus sieboldii ×P. gradidentata), under the control of the original promoter of the prxA3a gene. Eleven transformed aspens were obtained and characterized, and the stable integration of the antisense construct was
confirmed by PCR and Southern blotting analysis in all these lines. Assays of enzymatic activity showed that both total peroxidase
activity and acidic peroxidase activity were lower in most transgenic lines than in the control plants. In addition, the reduction
of peroxidase activity was associated with lower lignin content and modified lignin composition. Transgenic lines with the
highest reduction of peroxidase activity displayed a higher syringyl/vanillin (S/V) ratio and a lower S+V yield, mainly because
of a decreased amount of V units. Thus, our results indicate that prxA3a is involved in the lignification of xylem tissue and that the down-regulation of anionic peroxidase alters both lignin content
and composition in hybrid aspen. 相似文献
8.
Mène-Saffrané Laurent Esquerré-Tugayé Marie-Thérèse Fournier Joëlle 《Molecular breeding : new strategies in plant improvement》2003,12(4):271-282
Plant lipoxygenases (LOXs) are key enzymes involved in the generation of fatty acid derivatives, called oxylipins. In tobacco, LOX gene expression and activity are very low in healthy tissues and are highly enhanced in response to infection by Phytophthora parasitica nicotianae and to elicitor treatment. We previously showed, using antisense-LOX1 plants, that expression of the tobacco LOX1 gene is required for the race-cultivar specific resistance of tobacco to Phytophthora parasitica nicotianae. In order to investigate the effect of over-expressing a LOX gene on plant resistance, we transformed tobacco plants with the LOX1 coding sequence fused to the CaMV 35S promoter. Four transgenic lines with enhanced levels of LOX protein and specific activity over control plants were selected for further analysis. These plants were macroscopically indistinguishable from WT plants. Upon stem inoculation, the sense-LOX1 plants displayed a significantly decreased susceptibility to virulent races of Phytophthora parasitica nicotianae, stem lesions being 2- to 3-fold shorter in the transgenic lines than in WT plants. Using a root inoculation assay, the survival rate of sense-LOX1 seedlings was increased about 4-fold compared to their WT counterparts, with 60 to 80% of transgenic plants vs 15 to 20% of WT controls remaining healthy following inoculation with Phytophthora parasitica nicotianae. This is the first demonstration that the over-expression of a LOX gene is sufficient to reduce the susceptibility of a host plant to an oomycete pathogen. 相似文献
9.
S. S. Ibragimova Ya. S. Kolodyazhnaya S. V. Gerasimova A. V. Kochetov 《Russian Journal of Plant Physiology》2012,59(1):88-96
The role of gene of proline dehydrogenase (PDH) in the maintenance of stress tolerance was investigated using the model transgenic
plants of tobacco (Nicotiana tabacum L.) carrying an antisense suppressor of PDH gene (a fragment of Arabidopsis PDH gene under the control of cauliflower mosaic virus 35S promoter in antisense orientation) and notable for a low activity
of PDH and elevated content of proline. The progeny of transgenic plants belonging to the 5th generation (T5) with partially suppressed PDH activity was more resistant to various types of stress as compared with the control plants of tobacco, cv. Petit Havana SR-1
(SR1). The seedlings of transgenic lines cultured in Petri dishes on agar media supplemented with stress agents were resistant
to high NaCl concentrations (200–300 mM) and water deficit simulated by an increased agar content in the medium (14 g/l) as
compared to the control seedlings of cv. SR1. Juvenile plants of transgenic lines grown in pots filled with a mixture of vermiculite
and perlite also manifested the higher resistance to water deficit and low temperatures (2°C and −2°C) than the control plants.
Thus, the partial PDH suppression correlated with an increase in nonspecific resistance to different types of abiotic stress: salinity, water deficit,
and low temperatures. Such transgenic lines of tobacco are promising genetic models for thorough investigation of molecular
mechanisms of stress resistance in plants. 相似文献
10.
Ha Van Huan Ho Van Giang Ngo Van Thanh Siliang Zhang Yong Wang 《Molecular breeding : new strategies in plant improvement》2012,29(1):173-180
Reducing the lignin content of trees could provide both economic and environmental benefits. To this end, the coumarate:coenzyme
A ligase 1 gene (4CL1) was isolated from Pinus massoniana Lamb (Pm4CL1). The sequence of the full-length Pm4CL1 cDNA (accession no. FJ810495) contained an entire open reading frame (ORF) of 1,614 bp, which encoded a polypeptide of 537
amino acid residues. Tobacco (Nicotiana tabacum L.) as a model plant was used for functional characterization of the Pm4CL1 gene in transgenic plants. Results revealed that 4CL1 enzyme activity and lignin content in most antisense Pm4CL1 transgenic tobacco lines were decreased as compared to wild-type; the average 4CL1 enzyme activity was decreased by 48.75%
and lignin content was decreased by 24.5%. In contrast, in the sense Pm4CL1 transgenic tobacco lines, average 4CL1 enzyme activity was increased by 72.3% and lignin content was increased by 27.6%.
These results suggest that the Pm4CL1 gene from P. massoniana could be applied to regulate lignin biosynthesis in transgenic trees. 相似文献
11.
The DIANTHIN gene encoding a ribosome-inactivating protein (RIP) from Dianthus caryophyllus L. was tested for negative selection in tobacco and rice. Tobacco leaf discs and scutellum-derived callus of rice were transformed
with Agrobacterium tumefaciens strain LBA4404 (pSB1, pJAS1). pJAS1 harbors the DIANTHIN gene under the control of the CaMV 35S promoter. Tobacco transformation efficiency, in comparison to pCAMBIA1301, was reduced
by 87 % in pJAS1-transformed leaf discs. The DIANTHIN gene proved to be completely toxic to tobacco as all the recovered hygromycin-resistant transgenic plants harbored truncated
T-DNAs with deletions of the DIANTHIN gene. Transformation of the DIANTHIN gene under a Mungbean yellow mosaic virus (MYMV)-inducible promoter did not cause any toxicity in tobacco as reflected by the recovery of transgenic tobacco plants
with the complete DIANTHIN gene. Transformation efficiency of pJAS1 did not decline in rice. Interestingly, all transgenic rice plants harbored the
complete DIANTHIN gene and expressed the gene. The T1 transgenic lines showed reduction of sheath blight symptom in the range of 29 to 42 %. The difference in the sensitivity
to DIANTHIN between tobacco and rice provides a new direction to study the mechanisms underlying RIP toxicity in plants. 相似文献
12.
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
13.
J. Kveton 《Biologia Plantarum》2006,50(1):21-30
Three types of transgenic plants of Solanum tuberosum cvs. Kamyk and Oreb, and Nicotiana tabacum cvs. Maryland Mammoth and Trapezond were selected according to intensity of introduced ipt gene expression and resulting amount of synthesised cytokinins (CKs). In comparison with controls, original transgenic regenerants
grown in vitro showed a massive increase of CK contents, in tobacco by 379 % and in potato by 159 % (MAS). Potato grown in soil from tubers
of transgenic plants demonstrated a moderate increase (44 %) of CK contents (MOD). Transgenic tobacco grown from seeds in vitro did not show any significant change in CK contents (NOT). Initial (RuBPCi and RuBPOi) and total (RuBPCt) activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO), and the activity of phosphoenolpyruvate carboxylase (PEPC) were not significantly affected by the transformation in the NOT plants. In the MOD plants, the
RuBPCO activities were stimulated by up to 34 % whereas the PEPC activity was decreased by 17 %. On the other hand, all the
measured enzyme activities were 32 – 91 % lower in the MAS. Leaf area, fresh and dry masses, and chlorophyll and soluble protein
contents also went down with increasing CK amounts in the transformants. Dependence of RuBPCi/RuBPOi and RuBPCt/PEPC ratios on the relative CK amounts in transgenic plants revealed that the individual enzyme activities were not affected
uniformly. Endogenous CK contents in the MAS thus apparently exceeded an optimum needed for positive effects on many physiological
traits and became a stress factor for such plants. 相似文献
14.
A. Pal 《Plant biosystems》2016,150(5):932-941
The role of β-carbonic anhydrases (CAs) in C3 plant carbon assimilation is not clear. In this study, the primary role of C3 plant β-CAs in carbon assimilation was investigated for which, a chloroplastic β-CA gene (cacp) and a cytoplasmic β-CA gene (cacyt) from a C3 tree-legume of tropics, Leucaena leucocephala (leucaena) were overexpressed in Nicotiana tabacum (tobacco). The cacp and cacyt β-CA isoforms from leucaena were overexpressed separately and also together in tobacco resulting in three types of transgenic tobacco plants (i) expressing cacp only (ii) expressing cacyt only and (iii) co-expressing both cacp and cacyt. These transgenic plants exhibited significantly higher activity of β-CAs as compared with wild-type plants. The percent increase in the CA activity of transgenic plants expressing leucaena cacyt or cacp was found to be ~51 and ~55%, respectively. The transgenic tobacco expressing both the leucaena β-CA isoforms exhibited ~63% increase in CA activity as compared with the wild-type. However, despite notable increase in the CA activity of transgenic tobacco plants, no difference was observed in their phenotype, chlorophyll content and the overall dry weight compared with that of wild-type suggesting that C3 β-CAs are not involved in active accumulation of inorganic carbon. 相似文献
15.
Impact of different levels of cinnamyl alcohol dehydrogenase down-regulation on lignins of transgenic tobacco plants 总被引:1,自引:0,他引:1
Nabila Yahiaoui Christiane Marque Kathryn E. Myton Jonathan Negrel Alain Michel Boudet 《Planta》1997,204(1):8-15
The effects of cinnamyl alcohol dehydrogenase (CAD, EC.1.1.1.195) down-regulation on lignin profiles of plants were analysed
in four selected transgenic lines of tobacco (Nicotiana tabacum L. cv. Samsun) exhibiting different levels of CAD activity (8–56% of the control). A significant decrease in thioacidolysis
yields (i.e. yield of β-O-4 linked monomers) and in the ratio of syringyl to guaiacyl monomers (S/G) was observed for three transgenic lines and the
most drastic reduction (up to 50%) was correlated with the lowest level of CAD activity. Higher lignin extractability by mild
alkali treatment was confirmed, and, in addition to a tenfold increase in C6-C1 aldehydes, coniferyl aldehyde was detected by high-performance liquid chromatography in the alkali extracts from the xylem
of transgenic plants. In-situ polymerisation of cinnamyl aldehydes in stem sections of untransformed tobacco gave a xylem
cell wall coloration strikingly similar to the reddish-brown coloration of the xylem of antisense CAD-down-regulated plants.
Overall, these data provide new arguments for the involvement of polymerised cinnamyl aldehydes in the formation of the red-coloured
xylem of CAD-down-regulated plants.
Received: 24 January 1997 / Accepted: 14 May 1997 相似文献
16.
为了探索拟南芥AtCIPK23基因对烟草耐旱能力的影响,对3个转AtCIPK23基因阳性纯合株系KA13、KA14和KA44与野生型烟草K326(对照)进行了自然干旱处理,测定离体叶片的失水速率、叶绿素含量、相对电导率、脯氨酸和可溶性糖含量,并分析了转基因及野生型材料对活性氧的清除能力,对活性氧清除基因NtSOD、NtCAT和NtAPX及干旱胁迫相关基因NtDREB、NtLEA5和NtCDPK2的表达量进行检测。结果表明:(1)转基因烟草离体叶片的失水速率明显低于K326;自然干旱7 d后,野生型K326出现了明显的干旱胁迫症状;干旱7 d进行复水后,转基因株系的复水存活率明显高于K326。(2)转基因株系中的叶绿素、脯氨酸及可溶性糖含量比K326显著提高,电导率则明显降低。(3)野生型烟草K326中H2O2的积累量明显高于3个转基因株系,转基因株系中ROS清除机制的3个关键基因NtSOD、NtCAT和NtAPX被诱导上调表达。(4)抗旱相关基因NtDREB、NtLEA5和NtCDPK2仅在转基因烟草中受干旱诱导。研究认为,AtCIPK23基因可能具有提高植物抗旱能力的功能。 相似文献
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19.
Subbiyan Maruthasalam Yi Lun Liu Ching Mei Sun Pei Ying Chen Chih Wen Yu Pei Fang Lee Chin Ho Lin 《Plant cell reports》2010,29(9):1035-1048
Scientific evidences in the literature have shown that plants treated exogenously with micromole concentration of hydrogen
peroxide (H2O2) acquire abiotic stress tolerance potential, without substantial disturbances in the endogenous H2O2 pool. In this study, we enhanced the endogenous H2O2 content of tobacco (Nicotiana tabaccum L. cv. SR1) plants by the constitutive expression of a glucose oxidase (GO; EC 1.1.3.4) gene of Aspergillus niger and studied their cold tolerance level. Stable integration and expression of GO gene in the transgenic (T0–T2) tobacco lines were ascertained by molecular and biochemical tests. Production of functionally competent GO in transgenic
plants was confirmed by the elevated levels of H2O2 in the transformed tissues. When three homozygous transgenic lines were exposed to different chilling temperatures for 12 h,
the electrolyte conductivity was significantly lower in GO-expressing tobacco plants than the control plants; in particular, chilling protection was more prominent at −1°C. In addition,
most transgenic lines recovered within a week when returned to normal culture conditions after −1°C–12 h cold stress. However,
control plants displayed symptoms of chilling injuries such as necrosis of shoot tip, shoots and leaves, consequently plant
death. The protective effect realized in the transgenic plants was comparable to cold-acclimatized wild tobacco. The chilling
tolerance of transgenic lines was found associated, at least in part, with elevated levels of total antioxidant content, CAT
and APX activities. Based on our findings, we predict that the transgenic expression of GO may be deployed to improve cold tolerance potential of higher plants. 相似文献
20.
Guiping Diao Yucheng Wang Chao Wang Chuanping Yang 《Plant Molecular Biology Reporter》2011,29(1):77-87
Plant glutathione S-transferases (GSTs) are involved in protecting plants against both diverse biotic and abiotic stresses. In the present study,
a novel GST gene (LbGST1) was cloned from Limonium bicolor (Bunge) Kuntze (Plumbaginaceae). To characterize its function in salt tolerance, tobacco lines transformed with LbGST1 were generated. Compared with wild-type (WT) tobacco, transgenic plants overexpressing LbGST1 exhibited both GST and glutathione peroxidase activities. Moreover, superoxide dismutase, peroxidase (POD), and catalase
activities in transgenic plants were significantly higher than those in WT plants, particularly when grown under conditions
of salt stress. Similarly, levels of proline in transgenic plants were also higher than those in WT plants grown under NaCl
stress conditions. Whereas, Malondialdehyde contents in transgenic plants were lower than those in WT plants under NaCl conditions.
Furthermore, Na+ content in transgenic plants was lower than that in WT plants under these stress conditions. Subcellular localization analysis
revealed that the LbGST1 protein was localized in the nucleus. These results suggested that overexpression of LbGST1 gene can affect many physiological processes associated with plant salt tolerance. Therefore, we hypothesize that LbGST1 gene can mediate many physiological pathways that enhance stress resistance in plants. 相似文献