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A phosphorylation-based switch controls TAA1-mediated auxin biosynthesis in plants
Qian Wang1,2,3, Guochen Qin1, Min Cao1,2
1Shanghai Center for Plant Stress Biology, Centre for Excellence in Molecular Plant Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 201602, People's Republic of China.
Nature Communications
|February 5, 2020
Summary
Phosphorylation of TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA1) at T101 acts as a switch for auxin biosynthesis. This regulation is crucial for plant development and involves a self-regulatory loop with auxin signaling.
Area of Science:
- Plant Biology
- Molecular Biology
- Biochemistry
Background:
- Auxin is a key plant hormone regulating tissue development.
- Local auxin concentration is precisely controlled, mainly through transport.
- Regulation of local auxin biosynthesis is less understood.
Purpose of the Study:
- Investigate the regulation of auxin biosynthesis.
- Identify mechanisms controlling TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA1) activity.
- Explore the role of TAA1 phosphorylation in plant development.
Main Methods:
- Phosphorylation analysis of TAA1 at Threonine 101 (T101).
- Assessing the impact of T101 phosphorylation on TAA1 enzymatic activity.
- Investigating the role of TAA1 phosphorylation in root meristem and root hair development.
- Studying the interaction between auxin, TRANS-MEMBRANE KINASE 4 (TMK4), and TAA1.
Main Results:
- TAA1 is phosphorylated at T101, acting as an on/off switch for auxin biosynthesis.
- T101 phosphorylation is essential for regulating root meristem size and root hair development.
- The T101 phosphosite is evolutionarily conserved.
- Auxin, via TMK4, can induce T101 phosphorylation of TAA1, creating a feedback loop.
Conclusions:
- Phosphorylation-dependent control of TAA1 activity is a key mechanism for regulating auxin biosynthesis.
- This post-translational regulation allows plants to modulate auxin levels in response to cues.
- The findings suggest a general phenomenon of post-translational regulation in auxin biosynthesis across species.
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