Local phytochrome signalling limits root growth in light by repressing auxin biosynthesis
Kiki Spaninks1, Remko Offringa1
1Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, Netherlands.
Journal of Experimental Botany
|May 4, 2023
Summary
Light exposure inhibits plant root growth by affecting auxin levels. This study reveals a conserved mechanism in Arabidopsis and tomato, emphasizing the need for dark conditions in root research.
Area of Science:
- Plant Biology
- Molecular Physiology
Background:
- Plant shoots are light-exposed, while roots grow in darkness.
- In vitro root studies often incorrectly expose roots to light, potentially affecting development.
Purpose of the Study:
- Investigate the impact of direct root illumination on root growth and development.
- Determine if light-induced root growth inhibition is conserved in tomato.
Main Methods:
- Studied light effects on Arabidopsis and tomato roots.
- Analyzed phytochrome signaling pathways and auxin-related gene expression (YUCCA4, YUCCA6).
Main Results:
- Far-red/red light inhibits specific PHYTOCHROME INTERACTING FACTORS (PIFs) in light-grown Arabidopsis roots.
- This leads to decreased YUCCA4/YUCCA6 expression and suboptimal root apex auxin levels.
- Reduced root growth was observed in light-exposed conditions.
- The mechanism is conserved in tomato roots.
Conclusions:
- Direct root illumination inhibits root growth via phytochrome signaling and auxin regulation.
- Dark conditions are crucial for accurate in vitro root system architecture studies.
- The conserved mechanism has implications for horticultural practices.
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