Cellular and molecular mechanisms of the plant water stress response

Abstract

Plants respond to water stress by adaptation of the biochemical and physiological processes designed to improve the water status through combined inhibition of water loss by transpiration and more efficient access to the supplies of soil water. The biochemical and physiological reactions are regulated by precise molecular switches operating in a coordinated fashion Regulation is achieved at the level of gene expression (up- and down-regulation of transcripts), translational modification, modulation of the type and amount of intracellular solutes, and changes in osmolytes and phytohoimonal levels It is accomplished in an organ- and tissue-specific way. This review aims to summarize the recent advances in the understanding of the cellular and molecular mechanisms of the water stress response inplanta. The relationship of water stress to regulation of gene expression is accentuated, and the putative function of some of the better characterized water stressupregulated gene products is outlined. Future approaches directed toward characterization of the molecular mechanisms underlying the physiological responses to water stress are discussed, addressing the use of recombinant DNA techniques as a tool that may contribute to selection schemes in breeding programs for drought tolerance.