HPPD Polypeptide Mutations for Broad Herbicide Tolerance
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Solution Overview
Problem
Current methods for conferring tolerance to HPPD inhibitor herbicides in plants are inadequate for newer or diverse HPPD inhibitors, such as those belonging to the triketones, pyrazolinates, and N-(1,2,5-oxadiazol-3-yl)benzamides, with existing strategies showing limited success in providing agronomically acceptable tolerance levels.
Innovation Solution
Development of HPPD polypeptides with specific amino acid substitutions at positions 264, 268, 270, 335, 336, 337, 339, 340, and 345, encoded by nucleic acid sequences, which are introduced into plants to enhance tolerance to a broad range of HPPD inhibitor herbicides, including tembotrione, sulcotrione, and isoxaflutole, by modifying the HPPD enzyme's sensitivity and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing HPPD tolerance strategies are used, then some tolerance to HPPD inhibitors is achieved, but tolerance to newer and diverse HPPD inhibitors (triketones, pyrazolinates, oxadiazoles) is insufficient
Solution Approach 1:
The patent applies parameter changes by introducing specific amino acid substitutions at multiple positions (264, 268, 270, 335, 336, 337, 339, 340, and 345) in the HPPD polypeptide sequence. These parameter changes at the molecular level alter the enzyme's properties to confer tolerance to diverse HPPD inhibitors including triketones, pyrazolinates, and oxadiazoles, resolving the contradiction between achieving reliable tolerance and maintaining adaptability to new inhibitor classes.
2Reliability
If HPPD enzyme sensitivity is reduced through mutations, then herbicide tolerance increases, but enzyme catalytic activity may be compromised
Solution Approach 1:
The patent carefully selects specific amino acid positions (264, 268, 270, 335, 336, 337, 339, 340, and 345) for substitution to modify enzyme sensitivity to herbicides while preserving catalytic function. This targeted parameter change approach allows the HPPD enzyme to maintain its power (catalytic activity) while achieving the desired reliability (herbicide tolerance).
Solution Approach 2:
The patent applies local quality by making specific amino acid substitutions at particular positions in the HPPD polypeptide sequence rather than uniform modifications throughout. This localized modification strategy allows the enzyme to exhibit different properties at different regions - reduced sensitivity to herbicides at the binding interface while maintaining catalytic activity at the active site, thus resolving the contradiction between herbicide tolerance and enzymatic power.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The modified HPPD polypeptides confer increased tolerance to HPPD inhibitor herbicides, allowing plants to survive higher concentrations or longer exposure periods without significant growth inhibition, enabling selective weed control while maintaining crop productivity.
Implementation Method 1
The 4-hydroxyphenylpyruvate dioxygenases (HPPDs) are enzymes which catalyze the reaction in which para-hydroxyphenylpyruvate (abbreviated herein as HPP), a tyrosine degradation product, is transformed into homogentisate (abbreviated herein as HG)
Data Source
AI summary
Compositions and methods for conferring herbicide tolerance to bacteria, plants, plant cells, tissues and seeds are provided. Compositions include polynucleotides encoding herbicide tolerance polypeptides, vectors comprising those polynucleotides, and host cells comprising the vectors. The nucleotide sequences of the invention can be used in DNA constructs or expression cassettes for transformation and expression in organisms, including microorganisms and plants. Compositions also include transformed bacteria, plants, plant cells, tissues, and seeds. In particular, isolated polynucleotides encoding HPPD inhibitor tolerance polypeptides are provided. Additionally, amino acid sequences corresponding to the polynucleotides are encompassed.