Genetic engineering of salinity-tolerant plants

olecular techniques such as recombinant DNA technology may ultimately have their most significant effect on agriculture. Recent advances raise the possibility of the development of new plant germplasm through the introduction of any gene from any organism into plants. Several leading laboratories have achieved the transfer and expression of bacterial and foreign plant genes in plant cells. Increasing attention is now being paid to the use of recombinant DNA technology to isolate and transfer genes governing agriculturally important characteristics such as salinity and drought resistance. Plant geneticists in this field hope to develop new sources of stress-resistant germplasm for crops. The ultimate goal of producing stress-tolerant plants is so challenging that, in practice, an approach fully integrating molecular and other methods is most likely to succeed (fig. 1). The identification of salinity-tolerance genes, which can be transferred into plants using the new generations of vectors now being developed, is a critical aspect of the new molecular technology (fig. 2). Manipulation of salinity-tolerance genes using genetic engineering technology requires, first, a clear view of the physiological and biochemical steps involved in cellular adaptation to osmotic stress and, second, thorough knowledge of the osm gene or genes governing osmotic tolerance.