Taming abiotic stresses in plants through genetic engineering: current strategies and perspective

During the last decade, major advances have been made in plant genetic engineering. The methods for stable genetic transformation as well as for regulation of introduced trans-genes have been optimised to a great deal. The major limiting factor in the widespread application of genetic engineering is the availability of the target genes. This is particularly true for engineering tolerance against abiotic stresses (such as those caused by high levels of salts in soils, reduced/excess availability of water and sub- and supra-optimal temperature regimes). In spite of this, the past 5 years (1993-1998) have witnessed significant achievements in terms of generating transgenics for enhanced tolerance to these stresses. For future work on producing plants with still higher level of tolerance, there is a need to expand the information on the stress-induced genes so that appropriate genes can be pyramided. The current upsurge in genomic research has the potential to catalyse efforts in elucidating new stress-responsive genes. There are also possibilities of engineering the whole cascade of multiple genetic changes through manipulation of the regulatory genes