Integration of Abscisic Acid Signaling with Other Signaling Pathways in Plant Stress Responses and Development

Abstract

Plants are immobile and, to overcome harsh environmental conditions such as drought, salt, and cold, they have evolved complex signaling pathways. Abscisic acid (ABA), an isoprenoid phytohormone, is a critical signaling mediator that regulates diverse biological processes in various organisms. Significant progress has been made in the determination and characterization of key ABA-mediated molecular factors involved in different stress responses, including stomatal closure and developmental processes, such as seed germination and bud dormancy. Since ABA signaling is a complex signaling network that integrates with other signaling pathways, the dissection of its intricate regulatory network is necessary to understand the function of essential regulatory genes involved in ABA signaling. In the present review, we focus on two aspects of ABA signaling. First, we examine the perception of the stress signal (abiotic and biotic) and the response network of ABA signaling components that transduce the signal to the downstream pathway to respond to stress tolerance, regulation of stomata, and ABA signaling component ubiquitination. Second, ABA signaling in plant development processes, such as lateral root growth regulation, seed germination, and flowering time regulation is investigated. Examining such diverse signal integration dynamics could enhance our understanding of the underlying genetic, biochemical, and molecular mechanisms of ABA signaling networks in plants. 592 2 of 20 and developmental stages, plants were experiencing drought stress [5,[9][10][11][12][13][14][15][16][17]. Therefore, ABA is a misnomer [18], even though it plays a role in leaf senescence and seed dormancy, potentially via osmotic effects [19][20][21]. It has been observed that drought-stressed vegetative tissues of numerous plants accumulate ABA (40-fold induction) within hours of osmotic stress and then it decreases after rehydration. In addition, ABA has been considered a long-distance stress signal between shoots and roots [22]. Therefore, the study of spatiotemporal expression of genes that control ABA metabolism's rate-limiting steps is essential for understanding how plants adapt to stress. Other than its role in adaptation to abiotic stress, ABA has been shown to be a key regulator of pathogen virulence [23][24][25][26][27], which could offer insights into the basis of the ABA-synthesizing ability of numerous bio-and necrotrophic microbes [24,[28][29][30].Gene products acting in the vicinity of the cell wall or at the interface of the plasma membrane/cytoskeleton/cell wall are considered the most likely elements to participate in initial stress perception. For instance, gated aquaporins (plasma membrane intrinsic proteins (PIPs)) and osmo-/ion channels at the cell wall-plasma membrane interface may be implicated in the upstream perception [31][32][33]. The receptor of ABA remained unknown until 2009. Before then, several ABA receptors had been reported [34][35][36][37][38][39][40]; however, further investigations did not substantiate any o...

Genetic Network between Leaf Senescence and Plant Immunity: Crucial Regulatory Nodes and New Insights

“…SnRK2.3 interacts with and phosphorylates HAT1, an important transcriptional regulator in BR signaling, to repress its protein stability and binding activity, which increases expressions of ABA-responsive genes and then enhances tolerance to drought, indicating that a relationship between ABA and BR signaling pathways exists [149]. The cross-talks between ABA and other hormones in plant stress responses are discussed in details in several recently published papers [150,151].…”

Insight into the Role of Epigenetic Processes in Abiotic and Biotic Stress Response in Wheat and Barley

“…Through evolution, plants have acquired highly sophisticated systems to cope with various environmental stresses. The past decade has seen unprecedented progress in understanding the signaling pathways controlling the plant responses to stresses, which has been summarized in prior reviews [16][17][18]. Activation of these signaling pathways usually results in the dramatic transcriptional reprogramming to initiate a set of stress responses [19][20][21].…”

StABI5 Involved in the Regulation of Chloroplast Development and Photosynthesis in Potato

“…ABA is one of the most important phytohormones to fight against environmental stresses in various plants [1,2,43]. It also has an essential role in multiple physiological processes of plants, such as seed germination, lateral root formation, leaf senescence, and stomatal closure [43,44]. In-depth dissection of the biological functions of essential regulatory proteins in the ABA signaling pathway is necessary for understanding physiological and metabolic processes involved in ABA signaling.…”