PYL8 mediates ABA perception in the root through non-cell-autonomous and ligand-stabilization–based mechanisms

Significance The phytohormone abscisic acid (ABA) controls root responses to environmental signals such as abiotic stress. ABA signaling in roots depends on the nonredundant role of the PYL8 receptor. This study reveals special features of this ABA receptor. ABA binding triggers hormone-dependent stabilization of PYL8 through reduced ubiquitination and induces nuclear localization of the receptor. ABA-induced stabilization also allows movement of the PYL8 receptor from the root epidermis and stele to adjacent tissues. Hence, like mobile transcription factors that regulate plant development, the PYL8 protein can move between cells. In summary, our study reports a novel non-cell-autonomous mechanism to regulate hormone perception and root growth.