Resistance Against Stress - A number of genes responsible for providing resistance against stresses such as heat, cold, salt, heavy metals, phytohormones and nitrogen have been identified. Studies are also being conducted on metabolites like proline and betaines, that are implicated in stress tolerance. With this background, transgenic plants resistant to a variety of stresses will be produced in future.
In a recent report (Nature 23; April, 1992) results were described, where resistance against chilling (1 DC for 10 days) was introduced into tobacco plants, by introducing a gene for 'glycerol-I-phosphate acyl transferases enzyme from Arabidopsis (Arabidopsis is resistant to chilling).

The enzyme encoded by nuclear genome and later transported to chloroplast, determines the level of un saturation of fatty acids in the phosphatidyl glycerol of chloroplast membranes. The plants with high proportion of cis unsaturated fatty acids (e.g. spinach, Arabidopsis) are resistant to chilling, and so are the transgenic tobacco plants carrying the gene for the above enzyme.