1. Receptor for Activated C Kinase 1 counteracts ABSCISIC ACID INSENSITIVE5-mediated inhibition of seed germination and post-germinative growth in Arabidopsis.
- Author
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Li Z, Zhang D, Liang X, and Liang J
- Subjects
- Basic-Leucine Zipper Transcription Factors metabolism, Basic-Leucine Zipper Transcription Factors genetics, Gene Expression Regulation, Plant, Signal Transduction, Arabidopsis genetics, Arabidopsis growth & development, Arabidopsis metabolism, Arabidopsis physiology, Arabidopsis Proteins metabolism, Arabidopsis Proteins genetics, Germination, Receptors for Activated C Kinase metabolism, Receptors for Activated C Kinase genetics, Seeds growth & development, Seeds genetics, Seeds metabolism, Seeds physiology, Abscisic Acid metabolism
- Abstract
ABSCISIC ACID INSENSITIVE5 (ABI5), a key regulator of the abscisic acid (ABA) signalling pathway, plays a fundamental role in seed germination and post-germinative development. However, the molecular mechanism underlying the repression function of ABI5 remains to be elucidated. In this study, we demonstrate that the conserved eukaryotic WD40 repeat protein Receptor for Activated C Kinase 1 (RACK1) is a novel negative regulator of ABI5 in Arabidopsis. The RACK1 loss-of-function mutant is hypersensitive to ABA, while this phenotype is rescued by a mutation in ABI5. Moreover, overexpression of RACK1 suppresses ABI5 transcriptional activation activity for ABI5-targeted genes. RACK1 may also physically interact with ABI5 and facilitate its degradation. Furthermore, we found that RACK1 and the two substrate receptors CUL4-based E3 ligases (DWA1 and DWA2) function together to mediate the turnover of ABI5, thereby efficiently reducing ABA signalling in seed germination and post-germinative growth. In addition, molecular analyses demonstrated that ABI5 may bind to the promoter of RACK1 to repress its expression. Collectively, our findings suggest that RACK1 and ABI5 might form a feedback loop to regulate the homeostasis of ABA signalling in acute seed germination and early plant development., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
- Published
- 2024
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