Modified Citrus Tristeza Virus Vector Overcoming Superinfection Exclusion
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Solution Overview
Problem
Current virus-based transient expression vectors face challenges in infecting and expressing genes in tree crops due to long systemic infection times and superinfection exclusion phenomena, limiting their application and stability.
Innovation Solution
Engineered Citrus tristeza virus (CTV) constructs with modified leader protease sequences from different strains, lacking the p33 protein, or containing substitutions in the leader protease region, which overcome superinfection exclusion, allowing multiple applications and extended gene expression in trees.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If traditional virus-based transient expression vectors are used in tree crops, then gene expression can be achieved, but the time required for systemic infection exceeds the stability of known vectors and superinfection exclusion prevents multiple applications
Solution Approach 1:
The patent modifies the viral vector by changing its genetic parameters - specifically deleting the p33 gene and modifying the leader protease region. These parameter changes allow the vector to remain stable in trees for extended periods (months to years) while preventing superinfection exclusion, thus resolving the contradiction between duration of action and reliability.
2Productivity
If traditional virus-based transient expression vectors are applied to trees, then initial gene expression is achieved, but superinfection exclusion prevents subsequent vector applications
Solution Approach 1:
By deleting the p33 gene and modifying the leader protease region, the patent changes the viral vector's parameters to eliminate superinfection exclusion. This allows multiple sequential applications of the vector to the same tree, enabling researchers to apply different genes of interest over time while maintaining initial gene expression capability.
3Adaptability or versatility
If vectors are engineered to overcome superinfection exclusion, then multiple applications become possible, but vector complexity increases
Solution Approach 1:
The patent applies the extraction principle by removing the p33 gene from the viral vector genome. This deletion simplifies the vector construction process while achieving the desired outcome of overcoming superinfection exclusion. The modified vector can be generated through straightforward genetic engineering without requiring complex multi-component assemblies.
Data Source
AI summary
Disclosed herein are viral vectors suitable for transfection into woody trees for purposes of delivering and expressing beneficial genes. Specifically exemplified herein are vectors for transfecting citrus trees. The vectors allow for the expression of useful proteins, such as those that can protect the tree from disease. Specifically exemplified herein are methods of transfecting woody trees that allow multiple applications of vectors while avoiding superinfection exclusion.