PYR/PYL/RCAR Receptors Play a Vital Role in the Abscisic-Acid-Dependent Responses of Plants to External or Internal Stimuli

Abstract

Abscisic acid (ABA) is a phytohormone that plays a key role in regulating several developmental processes as well as in response to stressful conditions such as drought. Activation of the ABA signaling cascade allows the induction of an appropriate physiological response. The basic components of the ABA signaling pathway have been recognized and characterized in recent years. Pyrabactin resistance, pyrabactin resistance-like, and the regulatory component of ABA receptors (PYR/PYL/RCAR) are the major components responsible for the regulation of the ABA signaling pathway. Here, we review recent findings concerning the PYR/PYL/RCAR receptor structure, function, and interaction with other components of the ABA signaling pathway as well as the termination mechanism of ABA signals in plant cells. Since ABA is one of the basic elements related to abiotic stress, which is increasingly common in the era of climate changes, understanding the perception and transduction of the signal related to this phytohormone is of paramount importance in further increasing crop tolerance to various stress factors.

Comparative transcriptome profiling reveals the role of phytohormones and phenylpropanoid pathway in early-stage resistance against powdery mildew in watermelon (Citrullus lanatus L.)

“…Plants have a wide variety of active and passive defense mechanisms at their disposal in the event that they come under attack by pathogens ( Ausubel, 2005 ; Kumar et al., 2021 ; Benjamin et al., 2022 ). Active defense responses, which require de novo protein synthesis, are controlled by a complex and interconnected network of signaling pathways that primarily involve three molecules, ethylene (ET), jasmonic acid (JA) and salicylic acid (SA) and which results in the synthesis of pathogenesis-related (PR) proteins ( Jones and Dangl, 2006 ; Sood et al., 2021 ; Fidler et al., 2022 ). In both compatible and incompatible PM reactions, KEGG pathway analysis found hormone-signaling-related genes that code for receptors and response factors.…”

“…Auxins, cytokinins, gibberellins, jasmonic acid, salicylic, acid ethylene, abscisic acid, and brassinosteroid are phytohormones that respond to stress by acting synergistically and antagonistically in a process known as signaling cross talk ( Bostock, 2005 ; Sood et al., 2021 ; Gilroy and Breen, 2022 ). These phytohormones respond to environmental stimuli and developmental cues by harmoniously coordinating with one another ( Dopp et al., 2021 ; Fidler et al., 2022 ). All plant defensive responses are the consequence of the interaction of numerous genes and gene families that coordinate in a network ( Pandey and Somssich, 2009 ; Kumar et al., 2021 ).…”

“…These phytohormones regulate growth, development, and physiological activities in addition to defensive signals. Auxins, cytokinins, gibberellins, ethylene, jasmonic acid, brassinosteroid, salicylic acid, and abscisic acid are phytohormones that respond to stress by acting synergistically and antagonistically in a process known as signaling cross-talk ( Benjamin et al., 2022 ; Fidler et al., 2022 ). These phytohormones cooperate harmoniously and react to environmental and developmental factors.…”

The Alleviation of Metal Stress Nuisance for Plants—A Review of Promising Solutions in the Face of Environmental Challenges

“…Also in this case, the enhanced growth of Cd-stressed individuals sprayed with ABA was due to modification of the antioxidant defense systems. Interestingly, it is supposed that leaves-applied ABA can be then transferred to roots in order to regulate the response of the whole plant to metal stress [ 90 , 91 , 92 ]. ABA may also act positively on growth and physiological parameters under alkaline stress via effective control of ROS homeostasis, as found for alfalfa seedlings in which the enhanced activity SOD and POD was observed [ 93 ].…”

OsWRKY114 Negatively Regulates Drought Tolerance by Restricting Stomatal Closure in Rice

“…Finally, ABA is synthesized mainly in the vasculature of the leaves and is delivered to the guard cells via ABA importers, including ATP-binding cassette (ABC) transporter G family members (ABCGs) [ 2 ]. In guard cells, the pyrabactin-resistance 1/pyrabactin-resistance like/regulatory component of the ABA receptor (PYR/PYL/RCAR) recognizes ABA and inhibits type 2C protein phosphatases (PP2Cs), which are negative regulators of sucrose non-fermenting 1 (SNF1)-related protein kinases 2 (SnRK2s), thereby activating ABA signal transduction [ 3 ]. As a result, the osmotic pressure and volume of guard cells are decreased by the release of anions and K + , which stimulates stomatal closure to reduce transpirational water loss [ 4 , 5 ].…”