L422M/F442M PPO2 Polypeptide for PPO Inhibitor-Tolerant Crops
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Solution Overview
Problem
Weeds are a significant factor affecting crop yield, and existing PPO inhibitor herbicides can lead to resistance in weeds due to the accumulation of protoporphyrinogen, causing oxidative disintegration of plant cells. There is a need for herbicides that can effectively control weeds without inducing resistance.
Innovation Solution
Development of a PPO2 polypeptide with mutations at specific sites, such as L422M/F442M, which confers tolerance to PPO inhibitor herbicides, allowing for increased resistance in plants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PPO inhibitor herbicides are used to control weeds, then weed control effectiveness is improved, but weed resistance to herbicides develops
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of the PPO2 enzyme at specific positions (422 and 442). The mutation from wild-type to mutant forms (L422M, F442M, L422M/F442M) changes the biochemical parameters of the enzyme, allowing it to maintain catalytic activity while resisting herbicide inhibition. This molecular-level parameter change enables plants to tolerate PPO inhibitor herbicides that would otherwise kill them.
2Reliability
If PPO inhibitor herbicides are applied, then weed mortality increases, but protoporphyrinogen accumulates causing oxidative damage
Solution Approach 1:
The mutant PPO2 enzyme acts as an intermediary that allows protoporphyrinogen to be converted to protoporphyrin without accumulating to toxic levels. The modified enzyme maintains the metabolic flux through the heme synthesis pathway while being resistant to herbicide inhibition, thereby preventing the buildup of protoporphyrinogen that would otherwise undergo non-enzymatic oxidation and cause cellular damage.
3Adaptability or versatility
If PPO2 polypeptide mutations are introduced to confer herbicide tolerance, then plant resistance to herbicides increases, but enzyme structure changes
Solution Approach 1:
The patent applies local quality by making targeted amino acid substitutions at specific positions (422 and 442) within the PPO2 enzyme structure, rather than globally altering the enzyme. These localized mutations at the herbicide binding interface confer resistance while preserving the overall three-dimensional structure and catalytic function of the enzyme. The rest of the enzyme maintains its native structure and activity.
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 mutated PPO2 polypeptide enhances the tolerance of plants to PPO inhibitor herbicides, enabling effective weed control while maintaining plant health and reducing herbicide resistance.
Implementation Method 1
PPO catalyzes the conversion of protoporphyrinogen (Protoporphyrinogen IX) to protoporphyrin (Protoporphyrin IX)
Implementation Method 2
a PPO2 polypeptide with tolerance to protoporphyrinogen oxidase (PPO) inhibitor herbicides
Data Source
AI summary
The present invention relates to the technical field of biology, and provides a PPO2 polypeptide having tolerance to a PPO inhibitor herbicide and an application. When applied to a plant, the PPO2 polypeptide can greatly improve the resistance of the plant to a PPO inhibitor herbicide. The PPO2 polypeptide can be used for plants including cash crops, and can be selected to be used according to herbicide resistance characteristics and herbicides, thereby achieving the purpose of economically controlling weed growth.