Role of abscisic acid in plant stress tolerance

The phytohormone abscisic acid (ABA) plays a regulatory role in many physiological processes in plants. Different stress conditions such as water, drought, cold, light, and temperature result in increased amounts of ABA. The action of ABA involves modification of gene expression and analysis of responsive promoters revealed several potential cis- and trans-acting regulatory elements. The nature of ABA receptors is unknown. The precise role of ABA under both abiotic and biotic stress conditions, while unclear, is of current interest in many laboratories in the world. Molecular mechanisms underlying the role of ABA in stress tolerance in plants need to be understood.