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Structure-Based Directed Evolution of Rice 4-Hydroxyphenylpyruvate Dioxygenase Confers Enhanced Herbicide Tolerance
Jin Dong1,2, Jiangqing Dong3,4, Xin-Long Wang1,2
1State Key Laboratory of Green Pesticide, Central China Normal University, Wuhan 430079, PR China.
Journal of Agricultural and Food Chemistry
|July 16, 2025
Summary
Modifying 4-Hydroxyphenylpyruvate dioxygenase (HPPD) in rice can enhance herbicide resistance. Specific mutations in OsHPPD confer significant resistance, aiding molecular breeding for crop protection.
Area of Science:
- Agricultural Science
- Molecular Biology
- Biochemistry
Background:
- Precise gene modification is essential for molecular breeding and developing herbicide-resistant crops.
- 4-Hydroxyphenylpyruvate dioxygenase (HPPD) is a key enzyme in plant biochemical pathways and a target for herbicide action.
Purpose of the Study:
- To investigate the structural basis of 4-Hydroxyphenylpyruvate dioxygenase (HPPD) in rice (Oryza sativa) and identify modifications conferring herbicide resistance.
- To evaluate the impact of specific OsHPPD variants on enzymatic activity and herbicide tolerance in vitro and in vivo.
Main Methods:
- X-ray crystallography was used to determine the structure of Oryza sativa HPPD (OsHPPD) complexed with Methyl-Benquitrione (MBQ).
- Enzymatic assays were performed on C-terminal α9 helix variants of OsHPPD to assess catalytic efficiency.
- Herbicide resistance tests were conducted in vitro using various herbicides, and in vivo using Arabidopsis thaliana.
Main Results:
- The study identified potential residues in OsHPPD that confer herbicide resistance.
- Several K418D, E423Q, E423M, E432I, and E432M variants showed preserved catalytic efficiency.
- These variants demonstrated 1.5- to 3-fold enhanced resistance to herbicides like mesotrione, topramezone, MBQ, and A1.
- Forced expression of E432M in Arabidopsis thaliana significantly increased herbicide resistance compared to wild-type plants.
Conclusions:
- Specific modifications of OsHPPD can enhance herbicide resistance in plants.
- These findings provide a foundation for developing genetically engineered crops with improved weed management capabilities.
- Targeted mutations in HPPD offer a promising strategy for future crop improvement in agriculture.
