Transformation of Plant Cells

Summary

Techniques for the isolation and characterization of DNA fragments encoding the genetic information of many proteins of agricultural and medical importance have developed rapidly over the past decade. Several vector systems now permit the transfer of specific DNA sequences to plant cells, where they can be efficiently expressed. The tissue-specificity and temporal fidelity of expression of inserted gene sequences in transgenic plants that result from regeneration of transformed cells are remarkable. Inheritance of the acquired sequences is typically stable and Mendelian.

For many dicotyledons the Ti plasmid of Agrobacterium tumefaciens is an effective vector; recent reports indicate that it can also mediate transformation of a range of monocotyledons. Injection of DNA into plant meristems and introduction of DNA into protoplasts (facilitated by chemicals such as polyethylene glycol or by electroporation) are alternative approaches that may be especially suitable for monocotyledonous crops.

Rapid advances can be expected in the spectrum of plants modified by recombinant DNA technology and cell regeneration. Molecular processes of gene regulation and cell development are being elucidated. Many practical applications are evident, including the improvement of nutritional value and processing qualities of crop plant products. Commercial opportunities have already been demonstrated by the development of plants that are resistant to herbicides, insects and plant pathogens.