Synthetic Cry1Ac Gene Codon Optimization for Plant Expression
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Solution Overview
Problem
Current transgenic crops expressing Bacillus thuringiensis (Bt) toxins face challenges in achieving adequate pesticidal activity against lepidopteran pests due to poor expression and varying levels of Cry1Ac protein, which limits their effectiveness in controlling heliothine pests.
Innovation Solution
The development of synthetic nucleotide sequences encoding Cry1Ac pesticidal proteins, optimized for higher expression levels in plants and bacteria, which are used to create transgenic organisms with enhanced pest resistance and pesticidal activity, including transformed bacteria, plants, and seeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If native cry genes are used in transgenic crops, then the crops can produce Bt toxins, but the expression levels are poor and pesticidal activity is insufficient
Solution Approach 1:
The patent applies codon optimization to change the nucleotide sequence parameters of the cry1Ac gene to match plant codon usage preferences, thereby improving translation efficiency and protein expression levels while maintaining the amino acid sequence and pesticidal activity
Solution Approach 2:
The patent creates synthetic copies of the cry1Ac gene with optimized coding sequences that are designed specifically for high-level expression in plant systems, replacing the native bacterial gene sequence with a plant-optimized version
2Productivity
If codon optimization is applied to increase expression, then translation efficiency improves, but the gene sequence becomes synthetic and may lose native regulation
Solution Approach 1:
The patent systematically changes the nucleotide codon composition to match plant preferences while preserving the amino acid sequence, achieving high expression levels through codon optimization without altering the functional protein product
3Reliability
If commercial Bt cotton with modified cry1Ac is used, then lepidopteran pests are controlled, but heliothine pests are not adequately controlled due to varying Cry1Ac levels
Solution Approach 1:
The patent optimizes the cry1Ac gene coding sequence for high-level expression in plants, ensuring sufficient Cry1Ac protein accumulation to achieve reliable control of heliothine pests that were previously inadequately controlled
Solution Approach 2:
The patent proactively addresses the insufficiency of Cry1Ac levels by designing an optimized gene sequence that ensures adequate protein expression before pest pressure occurs, preventing the problem of inadequate control rather than reacting to it
Data Source
AI summary
Compositions and methods for conferring pesticidal activity to bacteria, plants, plant cells, tissues and seeds are provided. Compositions containing a synthetic nucleotide sequence encoding a Cry1 Ac protein are provided. The coding sequences can be used in DNA constructs or expression cassettes for transformation and expression in plants and bacteria. Compositions also include transformed bacteria, plants, plant cells, tissues, and seeds. In particular, isolated pesticidal nucleic acid molecules are provided, wherein the nucleotide sequences are set forth in SEQ ID NO: 5, 1, 2, 3, or 4, as well as variants and fragments thereof.