Cry1Ac Protein Peptide Insertion for Resistant Pink Bollworm Toxicity

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Solution Overview

Problem

The evolution of resistance in pink bollworm insects to Bacillus thuringiensis (Bt) toxins, particularly Cry1Ac, has reduced the effectiveness of Bt cotton technology, necessitating the development of novel insecticidal proteins with enhanced toxicity to counter this resistance.

Innovation Solution

Modification of the Cry1Ac protein by inserting gut binding peptides at specific sites identified using phage display libraries and in silico analysis to enhance toxin binding to the insect gut, thereby increasing toxicity against resistant pests.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Bt cotton technology is used extensively to control Lepidopteran insects, then insecticidal effectiveness is improved, but insect resistance evolves reducing the benefits

Engineering Contradiction:

Improveinsecticidal effectivenessVSAvoidresistance evolution

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent modifies the Cry1Ac protein by changing its binding parameters through peptide insertion. Specifically, gut binding peptides are inserted at specific positions (e.g., positions 282, 368, 508, or 523) in the Cry1Ac protein sequence, altering the toxin's affinity and specificity for insect gut receptors. This parameter change enables the modified toxin to bind effectively to resistant insect populations, reversing the resistance evolution problem while maintaining insecticidal effectiveness.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional Bt Cry toxins are used, then insecticidal activity is achieved, but binding to gut receptors is reduced in resistant populations

Engineering Contradiction:

Improveinsecticidal activityVSAvoidbinding to gut receptors

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces gut binding peptides as intermediary elements that mediate the interaction between the Cry1Ac toxin and the insect gut receptor. These peptides (e.g., sequences like AISPSRYFYDET, APTTWFNSDSIT, SANYNVQAGWTH, or WAMDGQQHSNNY) act as bridges that enhance the toxin's binding capability to the gut epithelium in resistant insects, overcoming the reduced binding problem while preserving insecticidal activity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If modified Bt toxins are developed to counter resistance, then toxicity against resistant pests is improved, but protein modification complexity increases

Engineering Contradiction:

Improvetoxicity against resistant pestsVSAvoidprotein modification complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the protein modification process into discrete, manageable components. Instead of creating entirely new toxins, it inserts specific peptide segments (3-12 amino acid sequences) at defined positions within the existing Cry1Ac protein framework. This segmentation approach (inserting peptides at positions 282, 368, 508, or 523) simplifies the modification complexity while achieving enhanced toxicity against resistant pests.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20260020575A1Modified insecticidal proteins with improved toxicity against lepidopteran insects

Publication Date: 2026.01.22 AJEET SEEDS PVT LTD

AI summary

The present invention provides modified Cry1Ac protein having enhanced toxicity towards resistant pink bollworm (PBW) species. Insertion of said specific, tightly binding gut peptides in Cry1Ac at one or more identified sites increases the retention of toxin in the PBW gut. resulting in solubilisation and pore formation leading to sepsis and larval death. The modified Bt toxin exhibits significant toxicity against resistant pink bollworm and thus can be used for generation of insect resistant transgenic plants.