dsRNA Trehalase Targeting for Asian Citrus Psyllid Control
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Solution Overview
Problem
Current methods lack an effective solution to reduce the transmission of Huanglongbing disease, caused by Candidatus Liberibacter species, which is spread by the Asian citrus psyllid (Diaphorina citri), as existing treatments are ineffective, and existing RNAi approaches have shown limited success in controlling Hemiptera populations without harming beneficial insects.
Innovation Solution
Development of a dsRNA solution targeting the trehalase gene specific to Diaphorina citri, which is administered through topical sprays, soil treatment, or genetically altered plants and microorganisms to reduce the fitness and mortality of the psyllid, utilizing a sense and anti-sense region complementary to the psyllid's trehalase cDNA, with an agriculturally acceptable carrier to ensure specificity and safety for beneficial insects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing RNAi approaches are used to control Hemiptera populations, then some reduction in pest populations is achieved, but beneficial insects are harmed
Solution Approach 1:
The patent applies local quality by designing dsRNA sequences that are highly specific to Diaphorina citri trehalase gene, ensuring that the RNAi effect is localized to the target pest species. The sequence specificity (SEQ ID NOs: 1-25) is engineered to match only D. citri trehalase mRNA, preventing off-target effects on beneficial insects with different trehalase sequences.
Solution Approach 2:
The patent employs parameter changes by optimizing the dsRNA sequence parameters (nucleotide composition, length, specific regions of trehalase gene) to achieve maximum specificity to D. citri. The sequence is designed with unique characteristics of D. citri trehalase that differ from other Hemiptera species, changing the molecular recognition parameters to exclude non-target insects.
2Reliability
If conventional treatments are applied to control Asian citrus psyllid, then some disease transmission reduction is achieved, but effectiveness is limited
Solution Approach 1:
The patent replaces mechanical/chemical control systems with a biological molecular mechanism. Instead of using conventional insecticides or physical barriers, the invention uses dsRNA-triggered RNA interference, a molecular biological mechanism that specifically silences the trehalase gene in D. citri, disrupting its metabolism and reducing its ability to transmit Huanglongbing disease.
Solution Approach 2:
The patent introduces dsRNA as an intermediary substance that mediates between the treatment application and the target pest. The dsRNA acts as a molecular mediator that is taken up by D. citri during feeding, then triggers intracellular RNAi pathways to silence essential genes, providing a bridge between external treatment and internal pest disruption.
3Object-affected harmful factors
If dsRNA targeting trehalase gene is administered to Diaphorina citri, then mortality and fitness reduction are achieved, but delivery to the pest must be effective
Solution Approach 1:
The patent applies universality by developing a multi-functional delivery system where the same dsRNA composition can be delivered through multiple routes: topical spray application, soil treatment, and incorporation into plant tissues via genetically altered plants. This universal approach ensures effective delivery regardless of the specific application method chosen.
Solution Approach 2:
The patent employs self-service by designing the dsRNA composition to be self-delivering through the natural feeding behavior of D. citri. When psyllids feed on treated plants or come into contact with treated surfaces, they automatically ingest or absorb the dsRNA, eliminating the need for complex delivery mechanisms or additional application steps.
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 dsRNA solution effectively increases the mortality of Diaphorina citri, thereby reducing its infestation and the transmission of Candidatus Liberibacter species, while avoiding harm to beneficial insects, thus providing a biological control mechanism to combat Huanglongbing disease.
Implementation Method 1
The RNA has a region with double-stranded structure. Inhibition is sequence-specific in that the nucleotide sequences of the duplex region of the RNA and of a portion of the target gene are identical. Specifically, Fire, et al. (U.S. Pat. No. 6,506,559) disclose a method to inhibit expression of a target gene in a cell, the method involves introducing a double-stranded ribonucleic acid, dsRNA, into the cell in an amount sufficient to trigger the RNAi process which leads to inhibition of specific protein translation of the target gene's messenger RNA (mRNA).
Implementation Method 2
The RISC siRNA complex causes degradation of the targeted mRNA, thereby preventing translation into a protein. As used herein, a 'trigger' is any dsRNA molecule that causes RNAi activity against a specific gene.
Data Source
AI summary
dsRNA generated from D. citri trehalase gene is effective in reducing fitness and/or survival of D. citri. Thus genetically altered plants expressing the dsRNA and plants to which dsRNA solutions are applied increase D. citri mortality and reduce D. citri infestation. With reduced D. citri population, the spread of microorganisms for which D. citri is a vector is reduced. Such microorganisms include, but are not limited to, C. Liberibacter species, including: CLas, CLam, and CLaf. Thus, applying of the D. citri trehalase dsRNA to a plant reduces disease and/or microorganism transmission by killing D. citri that feed on the treated plant.