PP2A regulates shade avoidance response by dephosphorylating phytochrome-interacting factor 7 in Arabidopsis
Xingbo Cai1, Oihik Mitra1, Amariah Gustamante1
1Department of Molecular Biosciences and the Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, 78712, USA.
The Plant Journal : for Cell and Molecular Biology
|August 2, 2026
Summary
Protein phosphatase 2A (PP2A) dephosphorylates PHYTOCHROME-INTERACTING FACTOR 7 (PIF7) in shade. This PP2A-PIF7 interaction regulates plant shade avoidance responses and hypocotyl elongation growth.
Area of Science:
- Plant biology
- Molecular plant science
- Plant physiology
Background:
- Shade avoidance is a critical plant adaptation for light competition.
- PHYTOCHROME-INTERACTING FACTOR 7 (PIF7) mediates shade-induced elongation growth.
- The mechanism of PIF7 dephosphorylation in shade remains unknown.
Purpose of the Study:
- To identify the molecular regulators of PIF7 dephosphorylation under shade.
- To elucidate the biochemical pathway controlling PIF7 activity in shade avoidance.
Main Methods:
- Yeast two-hybrid screening
- Biochemical assays
- Genetic analysis in Arabidopsis thaliana
- Photobiological analysis
Main Results:
- Protein phosphatase 2A (PP2A) directly interacts with PIF7.
- PP2A regulatory subunits (B'α, B'β, B″α, B″β) associate with PIF7.
- Loss of PP2A function impairs shade-induced hypocotyl elongation, while overexpression enhances it.
- PP2A dephosphorylates PIF7 in vitro and acts in the PIF7 genetic pathway.
Conclusions:
- PP2A is a direct regulator of PIF7 activity.
- PP2A plays a crucial role in PIF7-mediated shade avoidance responses.
- This study reveals a novel function for PP2A in plant shade responses.
Keywords:
ArabidopsisPP2Aphytochromesphytochrome‐interacting factors (PIFs)protein phosphataseshade‐avoidance syndrome (SAS)More Related Videos
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