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A. V. Babwah C. S. Waddell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(5):802-809
The enzyme cytosine deaminase, encoded by the codA gene, catalyzes the deamination of the non- toxic compound 5-fluorocytosine (5-FC) to the highly toxic compound 5-fluorouracil
(5-FU). Cytosine deaminase activity is not found in higher plants and Brassica napus seedlings are unaffected by the presence of 5-FC in the growth medium. In codA-transformed B. napus seedlings, expression of cytosine deaminase results in a reduction of root and hypocotyl lengths, and a severe suppression
of true leaf development. This phenotype is dependent on the presence of the 5-FC substrate and no effects are seen in plants
grown in the absence of the substrate or in sibling plants lacking the transgene. The codA transformants have been assessed over three generations of growth and in each generation the transgene is stably inherited
and confers the same 5-FC-sensitive phenotype. Transfer of 5-FC-sensitive seedlings to soil results in the restoration of
normal growth in up to 100% of the seedlings. These results indicate that codA is a versatile dominant marker gene that can be used effectively in B. napus for substrate-dependent negative selection.
Received: 24 June 1999 / Accepted: 22 July 1999 相似文献
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细菌乙酰胆碱氧化酶基因(codA)在烟草的表达与抗盐能力的分析 总被引:10,自引:0,他引:10
将土壤细菌(A.globiformis)的乙酰胆碱氧化酶(COD)基因(codA)通过农杆菌介导转入到烟草中,应用抗性筛选得了抗性植株,PCR检测结果表明:codA已整合到抗性植株染色体中;Western印迹鉴定及金标免疫分子定位的结果表明:乙酰胆碱氧化酶基因(codA已整合到抗性植株染色体中;Western印迹鉴定及金标免疫分子定位的结果表明:乙酰胆碱氧化酶基因(codA)在转基因烟草中得到表达,表达产物COD定位在叶绿体中,通过对转基因植株的抗盐能力分析,结果表明转基因植株比对照植株具有更高的抗盐性,其中幼小植株(1.0-1.5cm)可在400mmol/LNaCl的培养基上存活30天以上,并获得具有一定抗盐性状的转基因植株(T4-400),能在300mmol/LNaCl浓度下较好生长;较大植株(6-8cm)能在400mmol/LNaCl浓度下较好生长。 相似文献
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Jitender Giri 《Plant signaling & behavior》2011,6(11):1746-1751
The accumulation of osmolytes like glycinebetaine (GB) in cell is known to protect organisms against abiotic stresses via osmoregulation or osmoprotection. Transgenic plants engineered to produce GB accumulate very low concentration of GB, which might not be sufficient for osmoregulation. Therefore, other roles of GB like cellular macromolecule protection and ROS detoxification have been suggested as mechanisms responsible for abiotic stress tolerance in transgenic plants. In addition, GB influences expression of several endogenous genes in transgenic plants. The new insights gained about the mechanism of stress tolerance in GB accumulating transgenic plants are discussed. 相似文献
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The codA transgene for glycinebetaine synthesis increases the size of flowers and fruits in tomato 总被引:1,自引:1,他引:0
The tolerance of various species of plant to abiotic stress has been enhanced by genetic engineering with certain genes. However, the use of such transgenes is often associated with negative effects on growth and productivity under non-stress conditions. The codA gene from Arthrobacter globiformis is of particular interest with respect to the engineering of desirable productive traits in crop plants. The expression of this gene in tomato plants resulted in significantly enlarged flowers and fruits under non-stress conditions. The enlargement of flowers and fruits was associated with high levels of glycinebetaine that accumulated in reproductive organs, such as flower buds and fruits. The enlargement of flowers was related to an increase in the size and number of cells, and reflected the pleiotropic effect of the codA transgene on the expression of genes involved in the regulation of cell division. 相似文献
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Enhanced tolerance to light stress of transgenic Arabidopsis plants that express the codA gene for a bacterial choline oxidase 总被引:9,自引:0,他引:9
Alia Kondo Y Sakamoto A Nonaka H Hayashi H Saradhi PP Chen TH Murata N 《Plant molecular biology》1999,40(2):279-288
Arabidopsis thaliana was transformed with the codA gene from Arthrobacter globiformis. This gene encodes choline oxidase, an enzyme that converts choline to glycinebetaine. The photosynthetic activity, monitored in terms of chlorophyll fluorescence, of transformed plants was more tolerant to light stress than that of wild-type plants. This enhanced tolerance to light stress was caused by acceleration of the recovery of the photosystem II (PS II) complex from the photo-inactivated state. The transformed plants synthesized glycinebetaine, but no changes were detected in the relative levels of membrane lipids or in the relative levels of fatty acids in the various membrane lipids. Transformation with the codA gene increased levels of H2O2, a by-product of the reaction catalyzed by choline oxidase, by only 50% to 100% under stress or non-stress conditions. The activity of ascorbate peroxidase and, to a lesser extent, that of catalase in transformed plants were significantly higher than in the wild-type plants. These observations suggest that H2O2 produced by choline oxidase in the transformed plants might have stimulated the expression of H2O2 scavenging enzymes, with resultant maintenance of the level of H2O2 within a certain limited range. It appears that glycinebetaine produced in vivo, but not changes in membrane lipids or in the level of H2O2, protected the PS II complex in transformed plants from damage due to light stress. 相似文献
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