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HISTONE DEACETYLASE 9 promotes hypocotyl-specific auxin response under shade
Nguyen Hoai Nguyen1, Benny Jian Rong Sng1,2, Hui Jun Chin1
1Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore, 117604, Singapore.
The Plant Journal : for Cell and Molecular Biology
|July 31, 2023
Summary
Loss-of-function mutations in HISTONE DEACETYLASE 9 (HDA9) specifically reduce shade-induced hypocotyl elongation in Arabidopsis by impairing auxin-responsive gene activation. HDA9 interacts with PIF7, regulating shade avoidance responses.
Area of Science:
- Plant Biology
- Molecular Biology
- Genetics
Background:
- Shade avoidance syndrome (SAS) triggers plant morphological changes like hypocotyl elongation.
- HISTONE DEACETYLASE 9 (HDA9) is a key epigenetic regulator in plants.
Purpose of the Study:
- To investigate the role of HDA9 in regulating shade-induced hypocotyl elongation in Arabidopsis.
- To elucidate the molecular mechanisms by which HDA9 controls SAS.
Main Methods:
- Arabidopsis thaliana genetic mutant analysis (hda9).
- Organ-specific transcriptome analysis.
- Chromatin immunoprecipitation (ChIP) assays.
- Protein-protein interaction studies.
Main Results:
- hda9 mutants showed attenuated shade-induced hypocotyl elongation but not other SAS traits.
- HDA9 regulates shade-induced expression of auxin-responsive genes (SAURs, AUX/IAAs).
- HDA9 physically interacts with PHYTOCHROME-INTERACTING FACTOR 7 (PIF7) and binds to target gene loci.
Conclusions:
- HDA9 plays a specific role in hypocotyl elongation during shade avoidance.
- HDA9 acts as a transcriptional co-regulator, potentially recruited by PIF7, to activate auxin signaling in hypocotyls.
- This study reveals HDA9 as a crucial component of the hypocotyl-specific machinery controlling shade responses.
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