What happens during genetic modification? – Part 3 (Transferring Genes to Plant Cells)

In comparison to the transfer of genes into animals, transferring genes into plant cells is quite complex as the cells have a cell wall as well as a cell membrane. There are various methods used to introduce DNA into a plant.

http://newscenter.lbl.gov/wp-content/uploads/plant-cell-wall-copy.jpg

Firstly, bacteria that normally infects plants, resulting in tumours, can be used as a vehicle for transferring the genes. This bacteria is called Agrobacterium tumefaciens and is genetically altered to no longer possess a tumour-causing gene. The DNA is then added to it and the bacteria can be safely inserted into the plant; therefore the organism takes up the new gene.

http://bib2011genetik.wikispaces.com/file/view/Agrobacterium_tumefaciens.gif/212375160/Agrobacterium_tumefaciens.gif

Another method used to transfer genes into plants is called Electroporation. This involves the removal of the plant cell wall, followed by short bursts of electric current into the cell to create small pores. The new DNA can then move into the cell through these pores. This method can only be used on plants that are not natural hosts of Agrobacterium tumfactions (e.g. rice and corn plants).

http://gmcrops.yolasite.com/resources/IMG_electroporation.gif

A third method involves the insertion of the cloned DNA sections into the plant cell using an extremely fine needle. Firstly however, the cell wall needs to be removed so that the DNA can be delivered directly into the nucleus.

Using some of the above methods however, is often quite unsuccessful as a plant cell is very fragile without its cell wall. Therefore, there is a new technique in which, the DNA is ‘shot’ through the cell wall via a particle gun. The bullets of this particular gun are coated with DNA, made of metal, and are 2 micro metre wide. By using a certain level of force, the bullet passes through the thick wall and into the cell without compromising its structure. Once in the cell, the DNA diffuses away from the bullet until it reaches the nucleus and is incorporated into the original DNA of the plant.

http://users.comcen.com.au/~biodynamic/images/gene_gun1.jpg

Eat Safe!

Dr Georga Leisemann (Feeding Your Family)