Question

Select your favorite crop plant or model plant and find out what methods are available for its transformation, and in what year those methods were first published. How is the DNA introduced – by Agrobacterium, gene gun or other method? How are the transformed cells and plants selected, and how are transgenic plants regenerated?

Answer 1

Cotton plant is one of the major plant used for transformation. Methods availbale for transformation are :

1. Vector based and 2. Direct transfer.

Where transformation is to pass the specific foreign gene and introduce into the plant tissue where gene is for disease resistance or growth etc.,

1. Vector based transformation is done using plasmid as a vector of agrobacterium tumifaciens.plasmid is Ti plasmid.

The process of gene transfer of agrobacterium is:

It contains the T DNA sequence where some part of the TDNA is removed with the help of restriction enzyme and the gene of intrest is place and ligated the T DNA along with boarders ori of replication,virulent genes are introduced into the host so the gene of intrest T DNA integrated into host genome where there is a space and form recombination.

Direct method: 1. Electroporation 2. Shot gun method etc.,

The gene is introduced by electric signal so that the cell membrane ruptures and gene enters into cell where as shot gun method is DNA coated with metal or gold and bombarded to the cells under so that the gene is introduced into the cell.

Majorly agrobacterium vector based is used because of other methods might damage the tissue.

After gene transfer they are selected based upon the markers present in the vector that are anitbiotic resistant etc., The cell which is resistant can grow other wise they cannot survive in a media.

Later after selection plants are regenrated by using technique like somatic embryogenesis that is formation of the embryo to produce whole plant.