Structural analyses of ABA transporters give new impetus to the study of ABA regulation

Abscisic acid (ABA) is a plant hormone that regulates key physiological processes, including stomatal closure, seed germination and development, and is central to the coordination of abiotic stress responses. In the six decades since it was first described, a huge amount of work has been conducted on ABA synthesis, breakdown and signalling mechanisms.. ABA is synthesized mainly in vascular tissues and transported to distal sites to exert its physiological functions. This review presents an integrated overview of ABA metabolism and signalling. A major focus is placed on recent structural breakthroughs in the characterization of adenosine triphosphate ATP-binding cassette (ABC) transporters, particularly ABCG25, which have revealed detailed molecular mechanisms of ABA recognition, binding, and transmembrane transport. These discoveries, including transporter conformational dynamics and dimerization with ABCG16, reveal how ABA movement is tightly controlled across cell membranes and intracellular compartments. As climate change intensifies, understanding ABA transport offers a promising avenue for future plant breeding and agricultural innovation.