The genomic-scale EST and genome sequencing, and cDNA microarray analyses that are now under way promise to rapidly isolate and identify all candidate genes essential for tolerance of osmotic potential, desiccation or temperature stresses. The large datasets generated by these efforts will provide basis for functional analysis with the use of tagged mutant collections, complementation and overexpression tests accompanied by microarray analyses. By using yeast two-hybrid technologies, the specific protein-protein interactions will be well-understood. When the functions of all genes that participate in stress adaptation or tolerance reactions are determined, an integrated understanding of the biochemical and physiological basis of stress responses in plants will be obtained, and then, it will be therefore possible to rationally manipulate and optimize tolerance traits for improved crop productivity.