Introduction - Tissue Culture

Transformation is the step in the genetic engineering process where a new gene (transgene) is inserted into a single plant cell. The transformation step of producing a genetically engineered (GE) crop plant is a process controlled by poorly understood mechanisms. The process can be difficult because the genetic engineer must accomplish all of the following before they are successful.

  1. The new gene must be delivered into the nucleus of a cell and insert into a chromosome.
  2. The cells that receive the new gene must stay alive.
  3. The cells and plants that contain the new gene must be easilty identifiable (selectable markers).
  4. The transformed cell must divide and give rise to an entire plant.
  5. The location where the transgene inserts into the chromosome must not interfere with the expression of the gene.
  6. The new gene must not insert into an existing gene in the chromosome that influences survival of the plant cell or productivity of the entire plant.

Transformation is the step in the genetic engineering process where the new gene is inserted into a single plant cell. (Image by P. Hain)

Currently, geneticists have overcome these barriers by developing special techniques.

The first technique is tissue culture where clusters of undifferentiated plant cells are grown in culture, which allows them to be manipulated, and then induced to develop into whole plants.

The other technique is transformation where genetic engineers introduce the gene into these clustered cells using one of several possible methods including:

  • Agrobacterium tumefaciens
  • The gene gun (particle bombardment)
  • Electroporation
  • Microfibers.

This lesson will discuss the technique of tissue culture and how it is used in transformation. Transformation methods and results of the transformation process will be explained in the ’Transformation Methods’ and ’Events’ lessons.