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Arabidopsis lines with modified ascorbate concentrations reveal a link between ascorbate and auxin biosynthesis
M Fenech1,2, V Zulian3, J Moya-Cuevas2
1Department of Plant and Microbial Biology, College of Agriculture and Life Sciences, North Carolina State University, 112 Derieux Place, Raleigh, NC 27695-7614, United States.
Plant Physiology
|December 23, 2025
Summary
Plant antioxidant ascorbate impacts gene expression and interacts with auxin biosynthesis. Even varying ascorbate levels trigger similar transcriptional responses, highlighting complex redox homeostasis regulation.
Area of Science:
- Plant Biology
- Biochemistry
- Genetics
Background:
- Ascorbate (antioxidant) is vital for plant development, but its concentration effects on cellular homeostasis are unclear.
- Ascorbate levels naturally vary, making it a trait of nutritional and agronomic interest.
- Understanding ascorbate's role is crucial for plant science and agriculture.
Purpose of the Study:
- To investigate the impact of varying ascorbate concentrations on gene expression and cellular homeostasis in Arabidopsis thaliana.
- To identify molecular mechanisms linking ascorbate levels to plant stress responses and development.
Main Methods:
- Comparative analysis of Arabidopsis thaliana mutants (vtc2, vtc4) and overexpressors (vtc2/OE-VTC2) with distinct ascorbate levels.
- Gene expression profiling using transcriptomics to analyze transcriptional changes.
- Genetic and pharmacological studies on auxin biosynthesis and signaling pathways (TAA1, TAR2).
Main Results:
- Reduced ascorbate (80% decrease) upregulated defense genes but downregulated abiotic stress genes.
- High and low ascorbate levels (165% and 65% WT) induced similar transcriptional factors and gene ontology terms (85% overlap).
- TAA1, a key auxin biosynthesis gene, showed positive correlation with ascorbate content; auxin biosynthesis is essential for coping with high ascorbate in a light-dependent manner.
Conclusions:
- Ascorbate concentration significantly influences plant gene expression, affecting both defense and stress responses.
- Unexpected similarities in transcriptional programs between high and low ascorbate conditions suggest complex regulatory networks.
- A novel link between ascorbate homeostasis, light-dependent auxin biosynthesis (TAA1/TAR2), and redox regulation in plants was uncovered.
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