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1.
Tumor DNA structure in plant cells transformed by A. tumefaciens 总被引：25，自引：0，他引：25
P Zambryski M Holsters K Kruger A Depicker J Schell M Van Montagu H M Goodman 《Science (New York, N.Y.)》1980,209(4463):1385-1391
Crown gall tumors are induced in plants by infection with the soil bacterium Agrobacterium tumefaciens. Because the tumor induction involves transfer of a portion of the tumor-inducing (Ti) plasmid DNA from the bacterium to the plant cells, this system is of interest for the study of genetic exchange as well as tumor induction. The boundaries of the transferred DNA (T-DNA) have been cloned from transformed plant cells of tobacco. Detailed mapping with restriction enzymes and nucleotide sequence analysis of two independent clones were used to study the molecular structure of the ends of the T-DNA. One clone contains the two ends of the T-DNA joined together; the other contains one end of the T-DNA joined to repetitive plant DNA sequences. These studies provide direct evidence that the T-DNA can be integrated into the plant genome. In addition, the data suggest that in the plant, T-DNA can be tandemly repeated. Sequence analysis of the junction of crown gall clone 1 reveals several direct repeats as well as an inverted repeat; these structures may be involved in the transfer of the DNA from Agrobacterium to plant cells. 相似文献
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The transfer process of T (transfer)-DNA of Agrobacterium tumefaciens is activated after the induction of the expression of the Ti plasmid virulence (vir) loci by plant signal molecules such as acetosyringone. The vir gene products then act to generate a free transferable single-stranded copy of the T-DNA, designated the T-strand. Although some vir proteins are responsible for the synthesis of the T-strand, others may mediate T-strand transfer to plant cells as part of a DNA-protein complex. Here, a novel 69-kilodalton vir-specific single-stranded DNA binding protein is identified in Agrobacterium harboring a nopaline-type Ti plasmid. This protein binds single-stranded but not double-stranded DNA regardless of nucleotide sequence composition. The molecular size of the vir-specific single-stranded DNA binding protein and its relative abundance in acetosyringone-induced Agrobacterium suggested that it might be the product of the virE locus; molecular cloning and expression of the virE region in Escherichia coli confirmed this prediction. 相似文献
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Beijersbergen A Dulk-Ras AD Schilperoort RA Hooykaas PJ 《Science (New York, N.Y.)》1992,256(5061):1324-1327
Agrobacterium tumefaciens transfers part of its Ti plasmid, the transferred DNA (T-DNA), to plant cells during tumor induction. Expression of this T-DNA in plant cells results in their transformation into tumor cells. There are similarities between the process of T-DNA transfer to plants and the process of bacterial conjugation. Here, the T-DNA transfer machinery mediated conjugation between bacteria. Thus, products of the Vir region of the Ti plasmid of Agrobacterium tumefaciens, normally involved in transfer of DNA from bacteria to plants, can direct the conjugative transfer of an IncQ plasmid between agrobacteria. 相似文献
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农杆菌是一种革兰氏阴性土壤病原细菌,携带具有天然转基因功能的Ti质粒或Ri质粒,能将一部分遗传物质插入到寄主植物的染色体上,使其稳定遗传和表达,赋予植物新的性状。所以农杆菌作为最有效的转化媒介,已被广泛应用于多数双子叶植物和部分单子叶植物转基因研究。虽然农杆菌介导的转化技术具有操作简单、成本低廉,转基因沉默几率小,插入基因拷贝数少等优点,但农杆菌介导植物遗传转化是一个复杂的生物学过程,需要一系列农杆菌蛋白和植物蛋白相互作用,共同完成外源基因的转入和整合。植物相关蛋白在转化过程中起着重要作用。其中,阿拉伯半乳聚糖蛋白(AGP)、植物根钙粘附蛋白和类玻连蛋白等参与农杆菌附着于植物细胞表面的过程;鸟苷三磷酸腺苷酶（GTPase）和BTI蛋白协助T-DNA和Vir效应蛋白进入植物细胞;actin、GIP、VIP等蛋白参与T-DNA复合体在细胞质中的运输的过程;与Vir效应蛋白互作的VIP1、VIP2、KAPa、PP2C、Roc等蛋白协助T-DNA定位于植物细胞核;组蛋白、VIP1和VIP2等引导T-DNA在植物基因组上的整合。由于植物种类间存在巨大差异,上述一些植物蛋白基因的过表达虽能提高农杆菌转化某些植物的转化效率,但不能提高另一些植物的转化效率。在容易被农杆菌遗传转化的植物如拟南芥、水稻中的研究表明,VIP1、VIP2、AGP、H2A等蛋白与农杆菌转化关系密切,但这些蛋白在利用农杆菌转化较难的作物如小麦、玉米中的功能还不明确,因而需要在不同植物中继续筛选和鉴定与T-DNA转化相关重要蛋白的编码基因。目前,农杆菌介导的植物遗传转化有2个显著特点,一是农杆菌介导转化烟草、拟南芥、水稻等模式植物的技术日渐成熟,二是农杆菌介导转化小麦、玉米、大豆等重要作物的技术仍然没有本质突破,植物相关蛋白在T-DNA转运、整合等过程中的作用还需要深入研究和进一步明确。文章主要对参与农杆菌介导遗传转化植物整个过程中相关植物蛋白的研究进展进行了综述,以期为提高农杆菌转化顽拗型作物的转化效率提供参考。 相似文献
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Agrobacterium tumefaciens incites crown gall tumors when bacterial DNA integrates into plant nuclear DNA. Plant cells can express these integrated bacterial genes. Following insertion of desired genes into bacterial DNA using recombinant DNA techniques, this system permits introduction of these new genes into plant DNA. We discuss the potential for genetic manipulation of plants using Agrobacterium tumefaciens and the related organism Agrobacterium rhizogenes. 相似文献
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Caplan A Herrera-Estrella L Inzé D Van Haute E Van Montagu M Schell J Zambryski P 《Science (New York, N.Y.)》1983,222(4625):815-821
The tumor-inducing (Ti) plasmid of the soil microorganism Agrobacterium tumefaciens is the agent of crown gall disease in dicotyledonous plants. The Ti plasmid contains two regions that are essential for the production of transformed cells. One of these regions, termed transfer DNA, induces tumor formation and is found in all established plant tumor lines; the other, termed the virulence region, is essential for the formation but not the maintenance of tumors. Transfer DNA, which transfers to the plant genomes in a somewhat predictable manner, can be increased in size by the insertion of foreign DNA without its transferring ability being affected. The tumor-causing genes can be removed so that they no longer interfere with normal plant growth and differentiation. This modified Ti plasmid can thus be used as a vector for the transfer of foreign genes into plants. 相似文献
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The transfer of specific Ti (tumor-inducing) plasmid sequences, the T-DNA, from Agrobacterium tumefaciens to a wide range of plants results in the formation of crown gall tumors. These tissues differ from most plant cells in that they can be grown in vitro in the absence of added phytohormones. Here, data are presented that offer an explanation for the auxin-independent phenotype of crown gall tissues. It is shown that crude cell-free extracts prepared from three bacterial species harboring pTiA6 gene 1 could convert L-tryptophan to indole-3-acetamide; control extracts lacking gene 1 could not carry out the reaction. Other reports indicate that the pTiA6 gene 2 product can convert indole-3-acetamide to indole-3-acetic acid, a naturally occurring auxin of plants. It is concluded that the auxin-independent phenotype of crown gall tissue involves the introduction of Ti plasmid sequences encoding a two-step pathway for auxin synthesis. 相似文献
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刘卫平 《黑龙江八一农垦大学学报》2007,19(1):40-43
分别在温室和田间条件下利用人工接种的方法研究了PSTV和PVY在克新4号品种上的相互作用。试验结果表明:在温室条件下PSTV和PVY的复合接种能在克新4号上产生条型坏死症状,而在田间未出现明显症状。PSTV与PVY混合接种或PSTV接种一周后再接PVY会促进PVY增殖,植株内PVY的浓度显著高于单独接种PVY,但PVY侵染后再接PSTV对PVY的浓度无显著影响。PSTV和PVY的互作对PSTV的浓度无显著影响。PSTV与PVY复合侵染的3个接种类型都明显地降低平均单株产量和商品薯率,产量损失最大的处理为PSTV与PVY混合接种,可导致克新4号减产45.4%。 相似文献
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一段烟草核基质结合区的分离及对转基因表达的效果 总被引：1，自引：0，他引：1
采用PCR方法，从烟草基因组中分离了一段核基质结合区（matrix attachment region，MAR），将其构建到β-葡糖醛酸酶（β-glucuronidase，GUS）基因（uidA）的两侧翼，形成MARs调控的植物表达载体，将此表达载体与不含MARs序列的植物表达载体通过农杆菌转化烟草。对转基因植株进行GUS活性定量测定，结果表明，MAR可以提高外源uidA基因的表达水平，与不含MAR的转化植株相比，外源基因的平均表达水平提高了1.5倍，最高达6倍，但MAR的引入不能降低转基因植株个体间表达水平的差异。 相似文献
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Until recently, gene transfer in plants was achieved only by sexual hybridization. Now, in addition, plant genetic manipulation, with the use of both recombinant DNA and protoplast fusion technology, is being applied to an increasing range of plants. The soil bacterium Agrobacterium tumefaciens, with its associated plasmid, is used as a vector for introducing DNA into the genomes of dicotyledonous plants, but it has not proved suitable for cereals. Instead, the direct uptake of plasmid DNA into cereal protoplasts is being used for the transformation of cells in rice, wheat, and maize. Transformation efficiencies, in some cases, are becoming comparable to those obtained in dicotyledons with Agrobacterium. In rice it is now possible to regenerate efficiently whole plants from protoplasts, and this capability may soon be extended to the other cereals. By means of direct interaction of cereal protoplasts with plasmids, coupled with improved procedures for the regeneration of plants from their protoplasts, gene transfer in the cereals is becoming established at the frontiers of recombinant DNA technology. 相似文献
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Bacteria use conjugation systems, a subfamily of the type IV secretion systems, to transfer DNA to recipient cells. Despite 50 years of research, the architecture and mechanism of action of the channel mediating DNA transfer across the bacterial cell envelope remains obscure. By use of a sensitive, quantifiable assay termed transfer DNA immunoprecipitation (TrIP), we identify contacts between a DNA substrate (T-DNA) and 6 of 12 components of the VirB/D4 conjugation system of the phytopathogen Agrobacterium tumefaciens. Our results define the translocation pathway for a DNA substrate through a bacterial conjugation machine, specifying the contributions of each subunit of the secretory apparatus to substrate passage. 相似文献
15.
Transient and stable expression of the firefly luciferase gene in plant cells and transgenic plants 总被引：1，自引：0，他引：1
Ow DW DE Wet JR Helinski DR Howell SH Wood KV Deluca M 《Science (New York, N.Y.)》1986,234(4778):856-859
The luciferase gene from the firefly, Photinus pyralis, was used as a reporter of gene expression by light production in transfected plant cells and transgenic plants. A complementary DNA clone of the firefly luciferase gene under the control of a plant virus promoter (cauliflower mosaic virus 35S RNA promoter) was introduced into plant protoplast cells (Daucus carota) by electroporation and into plants (Nicotiana tabacum) by use of the Agrobacterium tumefaciens tumor-inducing plasmid. Extracts from electroporated cells (24 hours after the introduction of DNA) and from transgenic plants produce light when mixed with the substrates luciferin and adenosine triphosphate. Light produced by the action of luciferase was also detected in undisrupted leaves or cells in culture from transgenic plants incubated in luciferin and in whole transgenic plants "watered" with luciferin. Although light was detected in most organs in intact, transgenic plants (leaves, stems, and roots), the pattern of luminescence appeared to reflect both the organ-specific distribution of luciferase and the pathway for uptake of luciferin through the vasculature of the plant. 相似文献
16.
《（《农业科学与技术》）编辑部》2008,(2)
[Objective] The aim of this study is to obtain transgenic Lilium longiflorum Thumb. [Method] A two-step method of explant and the T-DNA integration technique were employed to transform Lilium longiflorum via Agrobacterium mediated method. [Result] The best infection effect appeared under the OD600 value of Agrobacterium within 0.6-0.8,the addition of 250 mg/L AS could increase the transformation efficiency. The optimal concentration of G418 for screening is 50 mg/L. Some putative transgenic plants of Lilium longiflorum with resistance to G418 showed positive in PCR,preliminarily proving that T-DNA gene had integrated into the genome of lily. [Conclusion] The study may lay a foundation for breeding excellent lily varieties through T-DNA integration technique. 相似文献
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LI Gang LIU Ju-hua TAN Guang-lan XU Bi-yu JIN Zhi-qiang Institute of Tropical Bioscience Biotechnology Chinese Academy of Tropical Agricultural Sciences Haikou 《（《农业科学与技术》）编辑部》2008,(2)
[Objective] The aim of this study is to obtain transgenic Lilium longiflorum Thumb. [Method] A two-step method of explant and the T-DNA integration technique were employed to transform Lilium longiflorum via Agrobacterium mediated method. [Result] The best infection effect appeared under the OD600 value of Agrobacterium within 0.6-0.8,the addition of 250 mg/L AS could increase the transformation efficiency. The optimal concentration of G418 for screening is 50 mg/L. Some putative transgenic plants of Lilium longiflorum with resistance to G418 showed positive in PCR,preliminarily proving that T-DNA gene had integrated into the genome of lily. [Conclusion] The study may lay a foundation for breeding excellent lily varieties through T-DNA integration technique. 相似文献
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[Objective] The aim of this study is to obtain transgenic Lilium longiflorum Thumb. [Method] A two-step method of explant and the T-DNA integration technique were employed to transform Lilium longiflorum via Agrobacterium mediated method. [Result] The best infection effect appeared under the OD600 value of Agrobacterium within 0.6 -0.8, the addition of 250 mg/L AS could increase the transformation efficiency. The optimal concentration of G418 for screening is 50 mg/L. Some putative transgenic plants of Lilium longiflorum with resistance to G418 showed positive in PCR, preliminarily pro-ring that T-DNA gene had integrated into the genome of lily. [Conclusion] The study may lay a foundation for breeding excellent lily varieties through T-DNA integration technique. 相似文献
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依据水稻端粒酶基因的相关生物学信息,构建了含有水稻端粒酶序列RNA干扰结构的植物表达载体pC am 23A-1-2,并利用农杆菌介导法将目的基因导入到粳稻品种日本晴中,获得了78个独立转化子,共165棵转基因植株。通过PCR和Southern杂交分析,证明RNA干扰结构已整合进水稻基因组中;应用染色体末端限制性片段分析法,显示在转基因水稻中端粒DNA序列长度有逐代缩短的趋势,初步证明这些转基因水稻中端粒酶亚基已失活,但是T0和T1代转基因水稻植株的主要农艺性状没有发生明显变化。 相似文献