DIG-13 Insecticidal Toxins for Resistant Corn Pests
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Solution Overview
Problem
Current Cry proteins used in transgenic corn for controlling Western corn rootworm (WCR) and European corn borer (ECB) exhibit incomplete larval control and are threatened by insect resistance, necessitating the development of new high-potency Cry proteins with different modes of action to maintain long-term efficacy.
Innovation Solution
The development of the DIG-13 insecticidal toxin and its variants, which can be used alone or in combination with existing Cry proteins, to control resistant populations by targeting specific genes in Coleopteran and Lepidopteran insects, and employing RNAi methodologies for enhanced pest management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current Cry proteins (Cry1Ab, Cry1Ac, Cry1F) are used in transgenic corn, then commercial levels of efficacy against ECB are achieved, but incomplete larval control and insect resistance development occur
Solution Approach 1:
The patent segments the insect control function by introducing multiple distinct Cry protein genes (Cry34Ab1, Cry35Ab1, Cry3Aa1, Cry3Bb1) that target different receptor systems in insects. This segmentation ensures that resistance to one Cry protein does not confer resistance to others, thereby maintaining reliability while preventing adaptability issues
Solution Approach 2:
The patent creates composite insect control systems by combining multiple Cry proteins with different modes of action into transgenic corn varieties. These composite systems (e.g., stacked traits expressing multiple Cry proteins) provide synergistic protection where the combined efficacy exceeds individual components, addressing both reliability and resistance concerns
2Reliability
If Cry34Ab1/Cry35Ab1, modified Cry3Aa1, and modified Cry3Bb1 are produced in transgenic corn roots, then robust protection against WCR root damage is achieved, but some WCR adults emerge indicating less than complete larval control
Solution Approach 1:
The patent modifies key parameters of Cry proteins including amino acid sequence variations, expression levels, and tissue distribution patterns to enhance potency. For example, modified Cry3Aa1 and Cry3Bb1 with altered sequences provide improved larval control while maintaining root protection, addressing the incomplete control issue
Solution Approach 2:
The patent implements dynamic expression systems where Cry protein expression is upregulated in response to insect detection or developmental stages. This dynamic response ensures robust protection when needed while minimizing effects on non-target organisms, improving complete larval control
3Adaptability or versatility
If multiple Cry proteins with different modes of action are produced in combination, then development of insect resistance is prevented, but device complexity increases
Solution Approach 1:
The patent merges multiple Cry protein genes into integrated transgenic stacks where genes are co-expressed in the same organism. This combining approach streamlines resistance management by providing multi-mode protection within a single genetic system, balancing adaptability benefits with manageable complexity through standardized vector construction
Data Source
AI summary
DIG-13 insecticidal toxins, polynucleotides encoding such toxins, use of such toxins to control pests, and transgenic plants that produce such toxins are disclosed.