The Chromatin-Remodeling Factor PICKLE Integrates Brassinosteroid and
Gibberellin Signaling during Skotomorphogenic Growth in
Arabidopsis |
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Authors: | Dong Zhang Yanjun Jing Zhimin Jiang Rongcheng Lin |
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Institution: | aKey Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;bUniversity of the Chinese Academy of Sciences, Beijing 100049, China;cNational Center for Plant Gene Research, Beijing 100093, China |
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Abstract: | Plant cell elongation is controlled by endogenous hormones, including brassinosteroid
(BR) and gibberellin (GA), and by environmental factors, such as
light/darkness. The molecular mechanisms underlying the convergence of these signals
that govern cell growth remain largely unknown. We previously showed that the
chromatin-remodeling factor PICKLE/ENHANCED PHOTOMORPHOGENIC1 (PKL/EPP1) represses
photomorphogenesis in Arabidopsis thaliana. Here, we demonstrated
that PKL physically interacted with PHYTOCHROME-INTERACTING FACTOR3 (PIF3) and
BRASSINAZOLE-RESISTANT1 (BZR1), key components of the light and BR signaling pathways, respectively. Also, this interaction
promoted the association of PKL with cell elongation–related genes. We found
that PKL, PIF3, and BZR1 coregulate skotomorphogenesis by repressing the
trimethylation of histone H3 Lys-27 (H3K27me3) on target promoters. Moreover, DELLA
proteins interacted with PKL and attenuated its binding ability. Strikingly,
brassinolide and GA3 inhibited H3K27me3 modification of histones
associated with cell elongation–related loci in a BZR1- and DELLA-mediated
manner, respectively. Our findings reveal that the PKL chromatin-remodeling factor
acts as a critical node that integrates light/darkness, BR, and GA signals to
epigenetically regulate plant growth and development. This work also provides a
molecular framework by which hormone signals regulate histone modification in concert
with light/dark environmental cues. |
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