Non-transgenic Sunflower PPO Mutation for Herbicide Tolerance
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Solution Overview
Problem
Current sunflower plants are highly susceptible to protoporphyrinogen IX oxidase (PPO) inhibiting herbicides, making it challenging to identify plants with sufficient herbicide tolerance, especially for post-emergence weed control, and there is a lack of non-transgenic sunflower plants resistant to a broad spectrum of PPO inhibitors.
Innovation Solution
Development of a non-transgenic sunflower plant with a mutated protoporphyrinogen IX oxidase gene featuring a phenylalanine to isoleucine substitution at position 383, which confers tolerance to PPO-inhibiting herbicides such as saflufenacil, allowing for effective weed control at later stages of growth without the use of transgenic methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional sunflower plants are used, then they are susceptible to PPO-inhibiting herbicides, but this makes it difficult to implement post-emergence weed control
Solution Approach 1:
The patent applies parameter changes by mutating the PPO enzyme's amino acid sequence (specifically substituting phenylalanine with isoleucine at position 383) to alter its herbicide binding characteristics. This changes the enzyme's parameter (substrate specificity) so that it no longer binds strongly to PPO-inhibiting herbicides, thereby conferring resistance while maintaining catalytic function
Solution Approach 2:
The patent creates a copy of the sunflower PPO2 gene and introduces a specific mutation (F383I substitution) in this copied gene. The mutated gene is then integrated into the sunflower genome, allowing the plant to produce a resistant PPO enzyme that is structurally similar to but functionally distinct from the wild-type enzyme
2Reliability
If transgenic methods are used to create herbicide-resistant plants, then resistance can be achieved, but non-transgenic resistant plants are needed
Solution Approach 1:
The patent employs mutagenesis techniques (chemical or physical) to induce random mutations in the sunflower's own PPO2 gene. The plant's cellular machinery then selects and stabilizes the mutated allele that confers herbicide resistance. This self-service approach generates resistance through the plant's own genetic system rather than introducing foreign transgenes
3Productivity
If PPO-inhibiting herbicides are applied to conventional sunflowers, then weed control is achieved, but the sunflower plants suffer damage or death
Solution Approach 1:
The patent applies local quality by creating a spatial and functional distinction between the wild-type PPO enzyme and the mutated PPO enzyme. The F383I mutation creates a localized change in the enzyme's active site that specifically confers herbicide resistance, while the rest of the enzyme maintains its native catalytic function. This allows selective resistance without affecting overall plant metabolism
Data Source
AI summary
The present invention relates to a non-transgenic sunflower plant comprising a mutated protoporphyrinogen IX oxidase (PPO) gene encoding a mutated sunflower protoporphyrinogen IX oxidase. The present invention further relates to a method of weed control at a plant cultivation site, comprising providing the plant of the present invention and applying to said site an effective amount of a PPO inhibiting herbicide. Further encompassed by the present invention is a method for producing sunflower oil.