Delta-endotoxin genes for multi-toxin pest resistance
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Solution Overview
Problem
The intensive use of B. thuringiensis-based insecticides has led to resistance in field populations of certain pests, such as the diamondback moth, due to mechanisms like reduced toxin binding to midgut receptors, which can also confer cross-resistance to other toxins.
Innovation Solution
Development of novel delta-endotoxin genes and their encoded proteins, along with their nucleic acid sequences, for use in transforming bacteria and plants to confer pest resistance, including the use of synthetic sequences and domain swapping to generate altered pesticidal proteins with improved activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If B. thuringiensis-based insecticides are used intensively, then pest control effectiveness is improved, but pest resistance develops
Solution Approach 1:
The patent combines multiple toxin genes (cry1A, cry2A, cry3A, cry4A) into a single transgenic plant, creating a multi-toxin expression system. This merging approach allows the plant to produce several different pesticidal proteins simultaneously, addressing resistance by providing multiple modes of action in one organism.
Solution Approach 2:
The invention creates a composite pesticidal system within the plant by integrating multiple toxin gene sequences. The resulting transgenic plant produces a composite of different crystal proteins that work together to control pests, similar to how composite materials combine different substances to achieve superior properties.
2Productivity
If conventional toxin genes are used, then initial pesticidal activity is achieved, but cross-resistance occurs
Solution Approach 1:
The patent applies local quality by assigning different toxin specificities to different gene components within the same plant. Each toxin gene (cry1A for lepidoptera, cry2A for diptera, cry3A for coleoptera, cry4A for nematodes) targets specific pest groups, creating localized effectiveness against different pest types while reducing the risk of cross-resistance.
Solution Approach 2:
The transgenic plant achieves multi-functionality by expressing multiple toxin genes that target different pest orders. This universal approach allows a single plant to control diverse pests (Lepidoptera, Diptera, Coleoptera, Nematodes) that would otherwise require different insecticide applications.
3Reliability
If novel toxin genes are developed, then resistance risk is reduced, but genetic engineering complexity increases
Solution Approach 1:
The patent segments the complex task of creating resistance management into separate toxin gene modules. Each gene (cry1A, cry2A, cry3A, cry4A) is an independent functional unit that can be individually characterized and combined. This segmentation makes the complex genetic engineering process more manageable and systematic.
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 approach enables the production of organisms with enhanced pesticidal activity, effectively controlling lepidopteran, coleopteran, and nematode pests while reducing the risk of resistance development, and can be used in agricultural settings to improve crop protection.
Implementation Method 1
The ingested protoxin is hydrolyzed by proteases in the insect digestive tract to an active toxic molecule
Implementation Method 2
This toxin binds to apical brush border receptors in the midgut of the target larvae and inserts into the apical membrane creating ion channels or pores
Data Source
AI summary
Compositions and methods for conferring pesticidal activity to bacteria, plants, plant cells, tissues and seeds are provided. Compositions comprising a coding sequence for a delta-endotoxin polypeptide are provided. The coding sequences can be used in DNA constructs or expression cassettes for transformation and expression in plants and bacteria. Compositions also comprise transformed bacteria, plants, plant cells, tissues, and seeds. In particular, isolated delta-endotoxin nucleic acid molecules are provided. Additionally, amino acid sequences corresponding to the polynucleotides are encompassed, and antibodies specifically binding to those amino acid sequences. In particular, the present invention provides for isolated nucleic acid molecules comprising nucleotide sequences encoding the amino acid sequence shown in SEQ ID NO:61-121 and 133-141, or the nucleotide sequence set forth in SEQ ID NO:1-60, 124-132, and 142-283, as well as variants and fragments thereof.