When the plant genome is altered by artificial introduction of one or few genes responsible for a desired trait, it is referred to as genetic transformation. Such genetically altered cell, when manipulated to develop into a whole plant, due to its totipotency, results in a transgenic plant. Though not all plants are amenable to such a transformation, this technology has resulted in the development of improved and novel varieties of some plant species. Unlike in conventional hybridization, the whole genome is not disturbed as only a few genes are inserted and hence, the time taken for establishment and multiplication is much lesser.

Ever since the introduction of tobacco as the first transgenic plant in 1983, several economically important plants like cotton, maize, soyabean, papaya, and the like are among about 18 transgenic crops introduced so far. Lot of research work undertaken since then has enhanced the understanding of regulation of gene expression and enabled recognition of regulatory sequences involved in differential expression of gene activity. With today’s technological knowhow, it is possible to isolate desired genes and integrate them into the genome of living plants, such that the genotype of the recipient plant is altered and also expressed.

When simplified, the steps involved in the generation of transgenic plants are

• isolation of desired gene from the donor organism;
• selection of a vehicle or vector that is to carry the gene;
• restructuring the vector before gene is inserted into it;
• gene insertion into the vector;
• transformation of the recipient cell through the vector;
• selection and identification of transformed cells;
• regenerating plants from such cells; and
• lab to field transfer of the regenerated plants and their sustenance.

Molecular biology techniques such as DNA isolation, gene restructuring, cloning, vector construction, identification of gene areas and what they code for, identification and selection of transformed cells are crucial to generation of transgenic plants. Likewise tissue culture techniques such as co-cultivation, protoplast fusion, organogenic differentiation, and lab to field transfer protocols are also important for their successful development.