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


Borja Belda-Palazon

Mary-Paz Gonzalez-Garcia

Jorge Lozano-Juste

Alberto Coego

Regina Antoni

Jose Julian

Marta Peirats-Llobet

Lesia Rodriguez

Ana Berbel

Daniela Dietrich

Maria A. Fernandez


Pedro L. Rodriguez


© 2018 National Academy of Sciences. All Rights Reserved. The phytohormone abscisic acid (ABA) plays a key role regulating root growth, root system architecture, and root adaptive responses, such as hydrotropism. The molecular and cellular mechanisms that regulate the action of core ABA signaling components in roots are not fully understood. ABA is perceived through receptors from the PYR/PYL/RCAR family and PP2C coreceptors. PYL8/RCAR3 plays a nonredundant role in regulating primary and lateral root growth. Here we demonstrate that ABA specifically stabilizes PYL8 compared with other ABA receptors and induces accumulation of PYL8 in root nuclei. This requires ABA perception by PYL8 and leads to diminished ubiquitination of PYL8 in roots. The ABA agonist quinabactin, which promotes root ABA signaling through dimeric receptors, fails to stabilize the monomeric receptor PYL8. Moreover, a PYL8 mutant unable to bind ABA and inhibit PP2C is not stabilized by the ligand, whereas a PYL8 5KR mutant is more stable than PYL8 at endogenous ABA concentrations. The PYL8 transcript was detected in the epidermis and stele of the root meristem; however, the PYL8 protein was also detected in adjacent tissues. Expression of PYL8 driven by tissue-specific promoters revealed movement to adjacent tissues. Hence both inter- and intracellular trafficking of PYL8 appears to occur in the root apical meristem. Our findings reveal a non-cell-autonomous mechanism for hormone receptors and help explain the nonredundant role of PYL8-mediated root ABA signaling.


Belda-Palazon, B., Gonzalez-Garcia, M., Lozano-Juste, J., Coego, A., Antoni, R., Julian, J., …Rodriguez, P. L. (2018). PYL8 mediates ABA perception in the root through non-cell-autonomous and ligand-stabilization–based mechanisms. Proceedings of the National Academy of Sciences, 115(50), E11857-E11863.

Journal Article Type Article
Acceptance Date Nov 5, 2018
Online Publication Date Nov 27, 2018
Publication Date Dec 11, 2018
Deposit Date Dec 14, 2018
Publicly Available Date May 28, 2019
Journal Proceedings of the National Academy of Sciences of the United States of America
Print ISSN 0027-8424
Electronic ISSN 1091-6490
Publisher National Academy of Sciences
Peer Reviewed Peer Reviewed
Volume 115
Issue 50
Pages E11857-E11863
Keywords Multidisciplinary
Public URL
Publisher URL


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