Mutated PPO Polypeptides for Herbicide Tolerance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for conferring herbicide tolerance on plants, particularly to PPO-inhibiting herbicides, are limited in effectiveness and specificity, as they often rely on general strategies that do not adequately address the diverse structural classes of these herbicides.
Innovation Solution
The development of mutated PPO polypeptides with specific amino acid substitutions at both active and non-active sites, encoded by polynucleotides that confer increased tolerance to PPO-inhibiting herbicides by altering the enzyme's sensitivity and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If general strategies are used to confer herbicide tolerance on plants, then broad applicability is achieved, but effectiveness and specificity against diverse PPO-inhibiting herbicides are limited
Solution Approach 1:
The patent introduces specific amino acid substitutions at targeted positions (e.g., R128A, G210S, F420M) within the PPO enzyme structure to create localized modifications that confer herbicide tolerance. This local quality change allows the enzyme to maintain its overall structure and function while gaining resistance to diverse PPO-inhibiting herbicides through specific structural alterations at critical sites.
Solution Approach 2:
The patent employs multiple amino acid substitutions that alter the physical and chemical parameters of the PPO enzyme, including charge distribution, hydrophobicity, and steric configuration. These parameter changes at positions such as R128, G210, and F420 modify the enzyme's interaction with herbicides, enabling tolerance across different herbicide classes while maintaining catalytic activity.
2Reliability
If multiple amino acid substitutions are introduced to enhance herbicide tolerance, then effectiveness against diverse herbicides is improved, but complexity of the polynucleotide sequence increases
Solution Approach 1:
The patent designs polynucleotide sequences that encode PPO variants with multiple amino acid substitutions, creating a single enzyme that performs multiple functions: maintaining native catalytic activity while simultaneously conferring tolerance to diverse PPO-inhibiting herbicides. The composite sequence integrates multiple mutation sites (e.g., R128A, G210S, F420M) into one functional unit that provides broad-spectrum herbicide resistance.
Solution Approach 2:
The patent constructs composite polynucleotide sequences that combine multiple mutated regions within a single gene structure. These composite sequences integrate amino acid substitutions at different positions (active site and non-active site) to create a synergistic effect, where the combined modifications provide enhanced herbicide tolerance that exceeds the sum of individual mutations.
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 expression of these mutated PPO polypeptides in plants significantly enhances their tolerance to various PPO-inhibiting herbicides, providing a targeted and effective solution for herbicide resistance.
Implementation Method 1
PPO catalyzes the last common step in chlorophyll and heme biosynthesis which is the oxidation of protoporphyrinogen IX to protoporphyrin IX
Data Source
AI summary
The present invention refers to a plant or plant part comprising a polynucleotide encoding a mutated PPO polypeptide, the expression of said polynucleotide confers to the plant or plant part tolerance to herbicides.