Implications of Abscisic Acid in the Drought Stress Tolerance of Plants

Abstract

Drought is a severe environmental constraint, which significantly affects plant growth, productivity, and quality. Plants have developed specific mechanisms that perceive the stress signals and respond to external environmental changes via different mitigation strategies. Abscisic acid (ABA), being one of the phytohormones, serves as an important signaling mediator for plants’ adaptive response to a variety of environmental stresses. ABA triggers many physiological processes, including bud dormancy, seed germination, stomatal closure, and transcriptional and post-transcriptional regulation of stress-responsive gene expression. The site of its biosynthesis and action must be clarified to understand the signaling network of ABA. Various studies have documented multiple sites for ABA biosynthesis, their transporter proteins in the plasma membrane, and several components of ABA-dependent signaling pathways, suggesting that the ABA response to external stresses is a complex networking mechanism. Knowing about stress signals and responses will increase our ability to enhance crop stress tolerance through the use of various advanced techniques. This review will elaborate on the ABA biosynthesis, transportation, and signaling pathways at the molecular level in response to drought stress, which will add a new insight for future studies.

Ameliorative Effects of Exogenous Proline on Photosynthetic Attributes, Nutrients Uptake, and Oxidative Stresses under Cadmium in Pigeon Pea (Cajanus cajan L.)

“…Metal stress in plants produces excessive amounts of reactive oxygen species (ROS), which lead to oxidative stresses [28,29]. The consequences of oxidative stress involve lipoperoxidation and oxidative damage to membrane lipids, enzymes, chloroplasts, and nucleic acids [28,29]. ROS molecules are extremely reactive, unstable, and toxic at elevated levels.…”

“…Plant metabolic activities generate ROS in small amounts. Under stress conditions, this ROS generation exceeds the maximum level [24,27], leading to oxidative stresses [28,29]. The consequences of oxidative stresses in plants involve lipid peroxidation, electrolyte leakage, and damage to membranes and DNA molecules [24,30,31].…”

Uptake, Translocation, and Consequences of Nanomaterials on Plant Growth and Stress Adaptation

“…In plants, the signaling network stimulates the defensive system, which triggers the molecular mechanism to respond to specific stress conditions. Calcium ions involved in the transduction of signals under varying stress environments act as a second messenger [151]. Sensitivity to stress signals causes the enrichment of calcium ion level in the cytosol through calcium ion channels, which is recognized by calcium ion-binding proteins that trigger alterations in gene expression as well as plant adaptation to stress conditions [152,153].…”

Ameliorative Effects of Calcium Sprays on Yield and Grain Nutritional Composition of Maize (Zea mays L.) Cultivars under Drought Stress

“…Additionally, Ca is involved in signaling anti-drought responses [32]. Calcium participated in abscisic acid (ABA)-induced drought signal transduction which improved water use efficiency and confer drought tolerance [27,28]. In addition, Ca-sensing proteins have shown to up-regulate drought tolerance signaling events, whereas negative regulation of drought stress is also attributed to these proteins [65].…”

“…It alleviates the harmful effects of drought on plants by signaling anti-drought responses [26]. Ali et al [27] indicated that the increasing cellular transient Ca participates in the processes abscisic acid (ABA)-induced drought signal transduction. The biosynthesis of ABA has improved water use efficiency and confer drought tolerance in plants [28].…”