Mutant Cry1Ac Proteins for Lepidoptera Pest Control
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Solution Overview
Problem
Conventional Bacillus thuringiensis (Bt) insecticides have limitations such as a narrow host spectrum and short shelf life, and the development of pest insect resistance, necessitating the development of novel endotoxin genes with broader host range and superior insecticidal activity against Lepidoptera pests.
Innovation Solution
Engineered mutant cry1Ac proteins with specific amino acid substitutions in domain I and II, which are encoded by novel nucleic acid molecules, are expressed in transgenic plants or applied as compositions to inhibit Lepidopteran pest growth, offering enhanced insecticidal activity and broader host range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional Bt insecticides are used, then pest control is achieved, but host spectrum is narrow and shelf life is short
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of the Cry1Ac protein through site-directed mutagenesis. Specific amino acid residues at positions 116, 128, 183, 187, 227, 245, 248, 254, 283, 286, 309, 322, 324, 334, 338, 340, 341, 375, 379, 381, and 412 were mutated to create variants with enhanced insecticidal activity and broader host spectrum against Lepidoptera pests.
Solution Approach 2:
The patent creates a composite protein structure by combining the Cry1Ac toxin protein with modified amino acid sequences that integrate properties from different protein regions. The mutated protein combines the crystalline inclusion formation capability with enhanced binding affinity to insect midgut receptors, achieving both broader host spectrum and maintained reliability.
2Reliability
If conventional Bt insecticides are used, then pest control is achieved, but pest insect resistance develops
Solution Approach 1:
The patent addresses resistance development by changing the molecular parameters of the toxin protein through multiple amino acid substitutions. These changes alter the protein's binding interface with insect receptors, creating a new binding mode that reduces selective pressure on insect populations and delays resistance evolution while maintaining effective insecticidal activity.
3Object-affected harmful factors
If wild-type Cry1Ac is used, then safety for non-target species is maintained, but insecticidal activity against resistant pests is reduced
Solution Approach 1:
The patent applies local quality by making specific targeted mutations at critical amino acid positions in the Cry1Ac protein while maintaining the overall protein structure and function. The mutations are localized to specific regions involved in receptor binding, allowing enhanced activity against resistant pests while preserving the safety profile for non-target species through controlled modification of specific functional domains.
Data Source
AI summary
The present disclosure discloses novel Cry1Ac mutants with improved insecticidal activity and/or spectrum against pests belong to Order lepidoptera. Also provided are transgenic plants expressing the present protein and methods for controlling Lepidopteran pest using the present mutants.