Cry Toxin Pyramids for Insect Resistance Management
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Solution Overview
Problem
The development of resistance by insects to the Cry1Fa protein, used in transgenic corn to control fall armyworm and European corn borer, poses a challenge as it reduces the effectiveness of the toxin over time due to genetic alterations in the insect gut receptors, potentially leading to decreased crop protection.
Innovation Solution
Stacking multiple Cry proteins, such as Cry1Fa with Cry2Aa, Cry1Ea, or other IRM toxins, to create triple stacks or 'pyramids' that provide separate modes of action, reducing the likelihood of cross-resistance and enhancing durability against insect pests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single Cry1Fa toxin is continuously present in the plant, then effective pest control is achieved, but insects can develop resistance through genetic alterations of the receptor
Solution Approach 1:
The patent combines multiple Cry toxins (Cry1Fa, Cry2Aa, Cry1Ea, Cry1Ia) into a single transgenic plant variety, creating a pyramid stack that expresses all four toxins simultaneously. This merging of multiple toxin modes of action prevents resistance development because insects would need to develop resistance to all four toxins at once, which is statistically improbable. The combination maintains reliable pest control while enhancing the duration of toxin effectiveness.
Solution Approach 2:
The patent creates a composite insecticidal system by integrating multiple Cry toxin genes into the plant genome. This composite approach uses toxins with different modes of action and target specificities, making the overall system more robust against resistance. The composite material strategy ensures that even if insects develop resistance to one toxin, the other toxins continue to provide protection.
2Reliability
If multiple Cry proteins are stacked to create pyramids, then resistance development is reduced, but device complexity increases
Solution Approach 1:
The patent segments the insect resistance management function into multiple independent toxin components, each with its own mode of action and target receptor. By dividing the protection function across four separate Cry toxins (Cry1Fa, Cry2Aa, Cry1Ea, Cry1Ia), the system achieves robust resistance management while allowing each component to be independently characterized and regulated.
Solution Approach 2:
The transgenic plant variety serves multiple functions simultaneously: it produces four different Cry toxins, each targeting different insect receptors and pathways. This multi-functionality allows a single crop variety to provide comprehensive pest control against both fall armyworm and European corn borer while managing resistance through diverse mechanisms of action.
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 approach significantly reduces the probability of insects developing resistance, maintaining the effectiveness of the transgenic crops and potentially eliminating the need for refuge acreage, thereby enhancing pest management and crop protection.
Implementation Method 1
This protein works by binding to specific receptor(s) located in the midgut of insects, and forms pores within the gut cells. The formation of these pores prevents insects from regulating osmotic balance which results in their death.
Implementation Method 2
Cry1Fa is the protein toxin currently in the HerculexTM brand of Dow AgroSciences transgenic corn seeds that are resistant to FAW and ECB insect pests. This protein works by binding to specific receptor(s) located in the midgut of insects
Data Source
AI summary
The subject invention relates in part to stacking certain Cry genes along with Cry 1Fa to result in products that are more durable and less prone towards insects developing resistance towards the activity of any of the toxins (such as Cry 1Fa) by itself. Embodiments of the Cry 1F stacking partners include Cry2Aa, Cry 1I, and Cry 1E. These stacks can be used to control FAW and/or ECB as described herein.