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'''Plant transformation vectors''' are [[plasmid]]s that have been specifically designed to facilitate the generation of [[transgenic plants]]. The most commonly used plant transformation vectors are [[binary vectors|T-DNA binary vectors]] and are often replicated in both ''[[E. coli]]'', a common lab [[Bacteria|bacterium]], and ''[[Agrobacterium tumefaciens]]'', a plant-virulent bacterium used to insert the [[recombinant
▲'''Plant transformation vectors''' are [[plasmid]]s that have been specifically designed to facilitate the generation of transgenic plants. The most commonly used plant transformation vectors are [[binary vectors|T-DNA binary vectors]] and are often replicated in both ''[[E. coli]]'', a common lab bacterium, and ''[[Agrobacterium tumefaciens]]'', a plant-virulent bacterium used to insert the recombinant (customized) DNA into plants.
▲Plant Transformation vectors contain three key elements;
* Plasmids Selection (creating a custom circular strand of DNA)
* Plasmids Replication (so that it can be easily worked with)
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==Steps in plant transformation==
A custom DNA plasmid sequence can be created and replicated in various ways, but generally, all methods share the following processes
Plant transformation using plasmids begins with the propagation of the binary vector in ''E. coli.'' When the [[bacterial culture]] reaches the appropriate density, the binary vector is isolated and purified. Then, a foreign gene can be introduced. The engineered binary vector, including the foreign gene, is re-introduced in ''E. coli'' for amplification.
The engineered binary factor is isolated from ''E. coli'' and is introduced into ''Agrobacteria'' containing a modified (relatively small) Ti plasmid. This engineered ''Agrobacteria'' can be used to infect plant cells. The T-DNA, which contains the foreign gene, becomes integrated into the plant cell genome. In each infected cell, the T-DNA is integrated at a different site in the genome.
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* Foreign DNA inserted
* [[Insertional mutagenesis]] (but not lethal for the plant cell – as the organism is diploid)
* Transformation DNA fed to rodents ends up in their [[phagocyte]]s and rarely in other cells. Specifically, this refers to bacterial and [[M13 bacteriophage|M13]] DNA. (This preferential accumulation in phagocytes is thought to be real and not a detection artefact since these DNA sequences are thought to provoke [[phagocytosis]].) However, no [[gene expression]] is known to have resulted, and this is not thought to be possible.<ref name="Goldstein-et-al-2005">{{cite journal | last1=Goldstein | first1=Daniel A. | last2=Tinland | first2=Bruno | last3=Gilbertson | first3=Lawrence A. | last4=Staub | first4=J.M. | last5=Bannon | first5=G.A. | last6=Goodman | first6=R.E. | last7=McCoy | first7=R.L. | last8=Silvanovich | first8=A. | title=Human safety and genetically modified plants: a review of antibiotic resistance markers and future transformation selection technologies | journal=[[Journal of Applied Microbiology]] | publisher=[[Society for Applied Microbiology]] ([[Wiley Publishing|Wiley]]) | volume=99 | issue=1 | year=2005 | issn=1364-5072 | doi=10.1111/j.1365-2672.2005.02595.x | pages=7–23| pmid=15960661 | doi-access= | s2cid=40454719 }}</ref><ref name="Lemaux-2008">{{cite journal | last=Lemaux | first=Peggy G. | title=Genetically Engineered Plants and Foods: A Scientist's Analysis of the Issues (Part I) | journal=[[Annual Review of Plant Biology]] | publisher=[[Annual Reviews (publisher)|Annual Reviews]] | volume=59 | issue=1 | year=2008 | issn=1543-5008 | doi=10.1146/annurev.arplant.58.032806.103840 | pages=771–812 | pmid=18284373 | bibcode=2008AnRPB..59..771L }}</ref>
==Plasmid selection==
A selector gene can be used to distinguish successfully genetically modified cells from unmodified ones. The selector gene is integrated into the plasmid along with the desired target gene, providing the cells with resistance to an [[antibiotic]], such as [[kanamycin]], [[ampicillin]], [[spectinomycin]] or [[tetracycline]]. The desired cells, along with any other organisms growing within the culture, can be treated with an antibiotic, allowing only the modified cells to survive. The antibiotic gene is not usually transferred to the plant cell but instead remains within the bacterial cell.
==Plasmids replication==
[[Plasmids]] replicate to produce many plasmid molecules in each host bacterial cell. The number of copies of each plasmid in a bacterial cell is determined by the [[replication origin]], which is the position within the plasmid molecule where DNA replication is initiated. Most
Plasmids can also be replicated using the [[polymerase chain reaction]] (PCR).
==T-DNA region==
T-DNA contains two types of genes: the [[Oncogene|oncogenic genes]], encoding for [[Enzyme|enzymes]] involved in the synthesis of [[Auxin|auxins]] and [[Cytokinin|cytokinins]] and responsible for [[tumor]] formation, and the genes encoding for the synthesis of [[Opine|opines]]. These compounds, produced by the condensation between [[Amino acid|amino acids]] and sugars, are synthesized and excreted by the crown gall cells, and they are consumed by A. tumefaciens as carbon and nitrogen sources.
The genes involved in opine [[catabolism]], T-DNA transfer from the bacterium to the plant cell and [[Bacterial conjugation|bacterium-bacterium plasmid conjugative transfer]] are located outside the T-DNA.<ref
==References==
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