Abscisic Acid: Emergence of a Core Signaling Network

• Published in: Annual review of plant biology Vol. 61; pp. 651 - 679
• Main Authors: Cutler, Sean R, Rodriguez, Pedro L, Finkelstein, Ruth R, Abrams, Suzanne R
• Format: Journal Article
• Language: English
• Published: United States 01.01.2010
• Subjects: abscisic acid; Abscisic Acid - metabolism; biochemical pathways; Gene Expression Regulation, Plant; kinases; literature reviews; mechanism of action; phosphatases; plant adaptation; plant development; plant hormones; plant physiology; plant stress; plants; Plants - metabolism; protein structure; receptors; Signal Transduction; stress tolerance
• ISSN: 1543-5008; 1545-2123
• DOI: 10.1146/annurev-arplant-042809-112122

Abscisic acid (ABA) regulates numerous developmental processes and adaptive stress responses in plants. Many ABA signaling components have been identified, but their interconnections and a consensus on the structure of the ABA signaling network have eluded researchers. Recently, several advances have led to the identification of ABA receptors and their three-dimensional structures, and an understanding of how key regulatory phosphatase and kinase activities are controlled by ABA. A new model for ABA action has been proposed and validated, in which the soluble PYR/PYL/RCAR receptors function at the apex of a negative regulatory pathway to directly regulate PP2C phosphatases, which in turn directly regulate SnRK2 kinases. This model unifies many previously defined signaling components and highlights the importance of future work focused on defining the direct targets of SnRK2s and PP2Cs, dissecting the mechanisms of hormone interactions (i.e., cross talk) and defining connections between this new negative regulatory pathway and other factors implicated in ABA signaling.