Chimeric Cry Proteins for Lepidopteran Pest Control
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Solution Overview
Problem
Current pest control methods, including chemical pesticides and biological agents, often have limited spectrum of activity and can lead to resistance in insect pests, necessitating the development of new, environmentally acceptable agents that can effectively target a broader range of economically important insect pests.
Innovation Solution
Development of novel chimeric genes encoding Cry proteins from Bacillus thuringiensis, including native and mutant forms with optimized codons for expression in transgenic organisms, which are highly active against specific insect pests and can be used to confer protection to plants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical pesticides are used to control insect pests, then pest control effectiveness is improved, but environmental harm and resistance development worsen
Solution Approach 1:
The patent changes the chemical structure parameters of pesticidal proteins by creating mutant Cry proteins with specific amino acid substitutions. These parameter changes in protein structure enhance pest control effectiveness while maintaining environmental safety, as the mutated proteins retain specificity to target pests and do not harm beneficial organisms or the environment like conventional chemical pesticides
Solution Approach 2:
The patent creates composite pesticidal compositions by combining multiple Cry proteins (e.g., Cry1A.105 and Cry2Ab2) with different modes of action and target specificities. This composite approach provides broader spectrum control and delays resistance development, reducing the need for repeated chemical pesticide applications that cause environmental harm
2Reliability
If existing Cry proteins are used to control insect pests, then control of specific pest species is achieved, but resistance in pest populations develops reducing long-term effectiveness
Solution Approach 1:
The patent modifies the amino acid sequence parameters of Cry proteins through site-directed mutagenesis to create variants with altered binding characteristics. For example, Cry1A.105 contains specific mutations that change its interaction with pest receptors, allowing it to overcome resistance mechanisms that have developed against wild-type Cry1Ac, thereby restoring long-term control effectiveness
Solution Approach 2:
The patent designs Cry proteins with multiple functions by engineering them to target multiple pest species or to overcome multiple resistance mechanisms simultaneously. The composite compositions contain proteins that work synergistically to provide both immediate control and long-term protection against resistance development across different pest populations
3Adaptability or versatility
If a broad spectrum of insect pests is targeted, then pest control coverage is improved, but specificity to non-target organisms may be reduced increasing environmental risk
Solution Approach 1:
The patent segments the pest control function by creating composite compositions where each Cry protein component targets a specific pest order or family. For example, Cry1A.105 primarily targets lepidopteran pests while Cry2Ab2 targets dipteran pests, allowing broad spectrum coverage through combination rather than through a single broad-spectrum toxin that would harm non-target organisms
Solution Approach 2:
The patent applies local quality by engineering each Cry protein variant to have enhanced specificity to particular pest species through localized amino acid changes in receptor-binding domains. This allows the proteins to distinguish between target and non-target organisms at the molecular level, providing broad coverage only against intended pests while leaving beneficial insects and non-target species unaffected
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
The novel Cry proteins demonstrate enhanced pesticidal activity against a wide range of economically important insect pests, including resistant strains, providing effective control while minimizing environmental impact.
Implementation Method 1
After ingestion by a pest, the crystals are typically solubilized to release protoxins
Implementation Method 2
Protoxins are converted into mature toxic fragments (approximately 60-70 kDa N terminal region) by gut proteases in the target pest
Implementation Method 3
Domain I, typically consists of seven alpha helices and is involved in membrane insertion and pore formation
Implementation Method 4
Domains II and III are involved in receptor recognition and binding, and are therefore considered determinants of toxin specificity
Data Source
AI summary
Novel insecticidal proteins isolated from Bacillus thuringiensis that are active against lepidopteran insect pests are disclosed. The DNA encoding the insecticidal proteins can be used to transform various prokaryotic and eukaryotic organisms to express the insecticidal proteins. These recombinant organisms can be used to control lepidopteran insects in various environments.