Cry1Ca and Cry1Ab Protein Combination for Insect Resistance Management
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Solution Overview
Problem
The development of resistance in insect populations to single insecticidal proteins used in transgenic plants poses a challenge for maintaining the effectiveness of Bt-based insect resistance traits, leading to cross-resistance issues and reduced efficacy over time.
Innovation Solution
The use of Cry1Ca in combination with Cry1Ab, along with the addition of Cry1Fa, creates an insect resistance management (IRM) stack that delays or prevents the development of resistance, as these proteins do not compete for binding sites in insect receptors, thereby maintaining their independent insecticidal effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single Bt insecticidal protein is used in transgenic plants, then the plant provides effective protection against target insect pests, but the insect population develops resistance to the protein over time, reducing its efficacy
Solution Approach 1:
The patent combines multiple Bt insecticidal proteins (Cry1Ab, Cry1Ac, Cry2Ab) into a single transgenic plant variety. This pyramiding strategy ensures that insects must develop resistance to multiple different proteins simultaneously, significantly delaying resistance development compared to single-protein varieties. The combined expression of these proteins maintains reliable insecticidal effectiveness while extending the duration of resistance protection.
Solution Approach 2:
The invention creates a composite insecticidal system by integrating multiple distinct Bt protein genes into the plant genome. This composite approach uses proteins with different modes of action and receptor binding specificities, making it difficult for insect populations to evolve resistance. The composite protein stack provides both immediate effectiveness and long-term durability against target pests.
2Reliability
If multiple Bt proteins are combined in a transgenic plant, then resistance development is delayed, but the complexity of the genetic stack increases
Solution Approach 1:
The patent employs a universal genetic architecture that integrates multiple Bt protein expression cassettes into a single transgenic plant variety. Each protein (Cry1Ab, Cry1Ac, Cry2Ab) serves a specific function in the resistance management strategy, targeting different insect receptors and pathways. This multi-functional design achieves comprehensive resistance delay while maintaining manageable genetic complexity through coordinated expression regulation.
3Productivity
If Bt proteins are deployed at high dose, then insect mortality increases, but the selection pressure for resistance development intensifies
Solution Approach 1:
The patent segments the insecticidal activity into multiple distinct protein components (Cry1Ab, Cry1Ac, Cry2Ab) with different modes of action. Instead of relying on a single high-dose protein that creates strong selection pressure, the invention distributes the control efficacy across multiple proteins at optimized doses. This segmentation reduces the selection pressure on any single protein while maintaining high overall insect mortality through the combined effect of multiple mechanisms.
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
This combination effectively controls sugarcane borer and fall armyworm populations that have developed resistance to Cry1Ab, and adds an additional mechanism of action against European corn borer, enhancing the durability of insect resistance in crops.
Implementation Method 1
The key predictor of lack of cross resistance inherent in this approach is that the insecticidal proteins do not compete for receptors in a sensitive insect species.
Data Source
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AI summary
The subject invention includes methods and plants for controlling lepidopteran insects, said plants comprising Cry1Ca insecticidal protein and a Cry1Ab insecticidal protein in combination to delay or prevent development of resistance by the insects.