Abscisic Acid Synthesis and Response

TLDR

Abscisic acid (ABA) is a classical plant hormone discovered over 50 years ago that regulates many aspects of plant growth and development. This chapter reviews current knowledge of ABA synthesis, metabolism, transport, and signal transduction, with an emphasis on Arabidopsis studies. Genetic, molecular, and biochemical studies have identified nearly all enzymes in ABA metabolism, almost 200 loci regulating ABA response, and thousands of ABA‑regulated genes, revealing cross‑talk with other signals and tissue‑specific signaling mechanisms that affect seed maturation, germination, seedling growth, stress responses, stomatal regulation, pathogen response, flowering, and senescence.

Abstract

Abscisic acid (ABA) is one of the "classical" plant hormones, i.e. discovered at least 50 years ago, that regulates many aspects of plant growth and development. This chapter reviews our current understanding of ABA synthesis, metabolism, transport, and signal transduction, emphasizing knowledge gained from studies of Arabidopsis. A combination of genetic, molecular and biochemical studies has identified nearly all of the enzymes involved in ABA metabolism, almost 200 loci regulating ABA response, and thousands of genes regulated by ABA in various contexts. Some of these regulators are implicated in cross-talk with other developmental, environmental or hormonal signals. Specific details of the ABA signaling mechanisms vary among tissues or developmental stages; these are discussed in the context of ABA effects on seed maturation, germination, seedling growth, vegetative stress responses, stomatal regulation, pathogen response, flowering, and senescence.