SMAX1 potentiates phytochrome B-mediated hypocotyl thermomorphogenesis
Young-Joon Park1, Jae Young Kim1, Chung-Mo Park1,2
1Department of Chemistry, Seoul National University, Seoul 08826, Korea.
The Plant Cell
|April 28, 2022
Summary
SUPPRESSOR OF MAX2 1 (SMAX1) enhances plant thermosensitivity by interacting with phytochrome B (phyB). This interaction regulates PIF4 transcription factor activity, controlling hypocotyl growth in response to temperature fluctuations.
Area of Science:
- Plant biology
- Molecular genetics
- Developmental biology
Background:
- Plants possess thermosensors to optimize development for ambient temperatures.
- Phytochrome B (phyB)-mediated thermosensing and gene networks for thermomorphogenesis are understood.
- Mechanisms for plant responsiveness to fluctuating temperatures remain unclear.
Purpose of the Study:
- To investigate the role of SUPPRESSOR OF MAX2 1 (SMAX1) in plant thermosensitivity.
- To elucidate how SMAX1 influences hypocotyl thermomorphogenesis in Arabidopsis thaliana.
- To understand the molecular regulation of thermosensing in response to temperature changes.
Main Methods:
- Genetic analysis of SMAX1-deficient mutants in Arabidopsis thaliana.
- Investigating protein-protein interactions between SMAX1, phyB, and PIF4.
- Analyzing the effect of temperature on SMAX1 protein stability and hypocotyl growth.
Main Results:
- SMAX1 enhances hypocotyl thermosensitivity, with disruptions observed in SMAX1-deficient mutants.
- SMAX1 interacts with phyB, relieving its suppression of PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) activity.
- Warm temperatures induce slow destabilization of SMAX1, preventing excessive hypocotyl elongation.
Conclusions:
- SMAX1 acts as a key regulator in thermosensing, promoting PIF4-mediated hypocotyl thermomorphogenesis.
- The abundance of SMAX1 is thermodynamically controlled, modulating phyB's function.
- This study reveals SMAX1's role as a molecular gatekeeper in plant thermomorphogenic responses.
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