ABSTRACT
Regulation of gene expression during plant stress is controlled by several different signaling mechanisms. One of the major signals is abscisic acid (ABA). In stresses in which ABA levels are increased, ABA recognition initiates a signal transduction pathway leading to the expression of many different genes. The expression of a large number of genes during water deficit is mediated to some extent by ABA, and many of these genes have been isolated. Compatible solutes accumulate in response to water deficit and are involved in the process of osmoregulation. Many studies of drought-regulated gene expression in higher plants have been conducted on drought-sensitive plants. As is true for water-deficit stress-induced genes, evidence exists to suggest that genes are regulated by salt stress in both an ABA-dependent and an ABA-independent manner. Abscisic acid has been implicated as a signaling molecule in local and systemic wounding.
