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  • Distinct guard cell–specific remodeling of chromatin accessibility during abscisic acid– and CO 2 -dependent stomatal regulation
Title: Distinct guard cell–specific remodeling of chromatin accessibility during abscisic acid– and CO 2 -dependent stomatal regulation
In plants, epidermal guard cells integrate and respond to numerous environmental signals to control stomatal pore apertures, thereby regulating gas exchange. Chromatin structure controls transcription factor (TF) access to the genome, but whether large-scale chromatin remodeling occurs in guard cells during stomatal movements, and in response to the hormone abscisic acid (ABA) in general, remains unknown. Here, we isolate guard cell nuclei fromArabidopsis thalianaplants to examine whether the physiological signals, ABA and CO2(carbon dioxide), regulate guard cell chromatin during stomatal movements. Our cell type–specific analyses uncover patterns of chromatin accessibility specific to guard cells and define cis-regulatory sequences supporting guard cell–specific gene expression. We find that ABA triggers extensive and dynamic chromatin remodeling in guard cells, roots, and mesophyll cells with clear patterns of cell type specificity. DNA motif analyses uncover binding sites for distinct TFs enriched in ABA-induced and ABA-repressed chromatin. We identify the Abscisic Acid Response Element (ABRE) Binding Factor (ABF) bZIP-type TFs that are required for ABA-triggered chromatin opening in guard cells and roots and implicate the inhibition of a clade of bHLH-type TFs in controlling ABA-repressed chromatin. Moreover, we demonstrate that ABA and CO2induce distinct programs of chromatin remodeling, whereby elevated atmospheric CO2had only minimal impact on chromatin dynamics. We provide insight into the control of guard cell chromatin dynamics and propose that ABA-induced chromatin remodeling primes the genome for abiotic stress resistance.  more » « less
Award ID(s):
1900567
PAR ID:
10550214
Author(s) / Creator(s):
;
Publisher / Repository:
PNAS Open Access
Date Published:
Journal Name:
Proceedings of the National Academy of Sciences
Volume:
120
Issue:
52
ISSN:
0027-8424
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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