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Title: GSK 3‐like kinase BIN 2 phosphorylates RD 26 to potentiate drought signaling in Arabidopsis
Abstract

Plant steroid hormones brassinosteroids (BRs) regulate plant growth and development at many different levels. Recent research has revealed that stress‐responsive NAC (petunia NAM and Arabidopsis ATAF1, ATAF2, and CUC2) transcription factorRD26 is regulated byBRsignaling and antagonizesBES1 in the interaction between growth and drought stress signaling. However, the upstream signaling transduction components that activateRD26 during drought are still unknown. Here, we demonstrate that the function ofRD26 is modulated byGSK3‐like kinaseBIN2 and protein phosphatase 2CABI1. We show thatABI1, a negative regulator inabscisic acid (ABA)signaling, dephosphorylates and destabilizesBIN2 to inhibitBIN2 kinase activity.RD26 protein is stabilized byABAand dehydration in aBIN2‐dependent manner.BIN2 directly interacts and phosphorylatesRD26in vitroandin vivo.BIN2 phosphorylation ofRD26 is required forRD26 transcriptional activation on drought‐responsive genes.RD26 overexpression suppressed the brassinazole (BRZ)  insensitivity ofBIN2 triple mutantbin2 bil1 bil2, andBIN2 function is required for the drought tolerance ofRD26 overexpression plants. Taken together, our data suggest a drought signaling mechanism in which drought stress relievesABI1 inhibition ofBIN2, allowingBIN2 activation. Sequentially,BIN2 phosphorylates and stabilizesRD26 to promote drought stress response.

 
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NSF-PAR ID:
10371905
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
The Plant Journal
Volume:
100
Issue:
5
ISSN:
0960-7412
Page Range / eLocation ID:
p. 923-937
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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