Update 3

Methods to Genetically Modify Plants For Roundup Ready

Original Paragraphs:

Agrobacterium tumefaciens is a widespread naturally occurring soil bacterium that causes crown gall, and has the ability to introduce new genetic material into the plant cell. The genetic material that is introduced is called T DNA(transferred DNA) which is located on a Ti plasmid. A Ti plasmid is a circular piece of DNA found in almost all bacteria. 

Most A. tumefaciens infections in plants occur in wounds, like those that sometimes result from grafting together different plant stocks. Once in the plant cell, the bacterial DNA inserts randomly into the plant genome and leads to changes in the production of certain plant hormones. These, in turn, can lead to the growth of tumors, or galls, that weaken the plant and can be fatal. 

This natural ability to alter the plant’s genetic makeup was the foundation of plant transformation using Agrobacterium. Currently, Agrobacterium-mediated transformation is the most commonly used method for plant genetic engineering because of relatively high efficiency. Initially it was believed that this Agrobacterium only infects dicotyledonous plants, but it was later established that it can also be used for transformation of monocotyledonous plants such as rice.

Key Points:

• Agrobacterium Tumefaciens, also known as A.Tumefaciens, is a categorised as a type of bacteria, which can mutate the genetic components of plants when infected.
• They primarily cause a disease called Crown Gall but can also cause tumours which hurts the plants' metabolism.
• This bacteria can alter the gene of plants by random insertion of their own DNA strand into the plants' genome and these DNA material is called T DNA, an abbreviation for transferred DNA.
• However, due to technological advancement, this particular bacteria is also utilised by scientist to genetically modify plants and is considered as the most efficient method to do so.

Paraphrasing:

DNA transfer through A. Tumefaciens
http://www.nepadbiosafety.net/abne/wp-content/uploads/2010/10/agrobacterium.jpg

Agrobacterium Tumefaciens

The very first method of genetic modification is through the organism Agrobacterium Tumefaciens also known as A.Tumefaciens. It is categorised as a type of bacteria, which can mutate the genetic components of plants when infected by random insertion of their own DNA strand into the plants' genome and these DNA material is called T DNA, an abbreviation for transferred DNA. They primarily cause a disease called Crown Gall but can also cause tumours which hurts the plants' metabolism. However, due to technological advancement, this particular bacteria is also utilised by scientist to genetically modify plants and is considered as the most efficient method to do so. Scientists had been able to conduct large scale experiment regarding it. Firstly, they isolate the genetic material coding for the desired allele and may slightly modify its structure, codon or markers to ensure successful development of protein in the Agrobacterium Tumefaciens. Then it is inserted to the Ti Plasmid containing the T DNA, which will be inserted to the Agrobacterium Tumefaciens itself. Following this, is the exposure of specific plant cell to the A.Tumefaciens, allowing the transfer of DNA. This modified cells is then cultured and regenerated into a genetically modified plant.

Biolistics

Gene Gun
http://www.bio-rad.com/webroot/web/images/lsr/products/
gene_transfer_rnai/product_detail/global/lsr_gene_gun.jpg

Another method of genetically modifying crops into roundup ready is through a considerably old method called biolistics developed in the 1980s by John Stanford. In this method, DNA of plants are genetically modified by using high density gold or tungsten micro-particles. Before the insertion of these micro-particles into the designated plant cell using pressurised-helium-powered gene gun, it is previously coated with the DNA. The gene guns help the particles to travel in high velocity, allowing the particles to go through the cell walls and cell membranes with ease. The foremost benefit of this method of genetic engineering is that it is applicable to a broader range of plant tissues compared to the Agrobacterium Tumefaciens. It could also be utilised to transform only certain parts of the plant, for example the chloroplast and mitochondria exclusively.

Electroporation

Illustration of the electroporation process
http://oncosec.com/wp-content/uploads/2012/07/OMS_Poration_Graphic_Light.png

Electroporation is a process of genetic engineering wherein new DNA is incorporated in the nucleus of a cell. It is done by electrocuting the cell, disrupting the plasma membrane, making it  temporarily more porous and permeable. The electrocuted cell will be placed in a special solution with the DNA corresponding to the selected traits and when the cell plasma becomes penetrable, it will enter the cell membrane. Thereupon these cells will be cultured using a protein-rich solution and its success will be confirmed.

* Information from paraphrasing does not solely come from the source of 'original paragraphs'.

Bibliography:

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"Plant Transformation Using Agrobacterium Tumefaciens - African Biosafety Network of Expertise (ABNE)." African Biosafety Network of Expertise ABNE. N.p., n.d. Web. 18 Oct. 2014. <http://www.nepadbiosafety.net/subjects/biotechnology/plant-transformation-agro>.

"The Genome of Agrobacterium Tumefaciens." The Genome of Agrobacterium Tumefaciens. N.p., n.d. Web. 18 Oct. 2014. <http://www.genomenewsnetwork.org/articles/12_01/A_tumefaciens_genome.shtml>.

"What Is Biolistics?" What Is Biolistics? N.p., n.d. Web. 18 Oct. 2014. <http://www.biotecharticles.com/Others-Article/What-is-Biolistics-522.html>.

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"Result Filters." National Center for Biotechnology Information. U.S. National Library of Medicine, n.d. Web. 18 Oct. 2014. <http://www.ncbi.nlm.nih.gov/pubmed/23143483>.

"Untitled Document." Untitled Document. N.p., n.d. Web. 18 Oct. 2014. <http://www.bio.davidson.edu/people/kabernd/seminar/2002/method/toran/paultmeth.html>.

McMahon, Mary, and O. Wallace. WiseGeek. Conjecture, 25 Sept. 2014. Web. 18 Oct. 2014. <http://www.wisegeek.com/what-is-electroporation.htm>