Cry14 Nematicidal Toxin Expression in Soybean
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Solution Overview
Problem
Current methods for controlling nematode pests in agriculture are limited, particularly for parasitic nematodes like Pratylenchus brachyurus, which cause significant economic losses and lack effective resistance in soybean varieties, with chemical controls being non-selective and disrupting beneficial microorganisms.
Innovation Solution
The use of a nematicidal toxin, specifically a polypeptide with the amino acid sequence of Cry14 or variants thereof, is introduced into plants to confer resistance by expressing it in plant cells or seeds, effectively killing or impairing nematodes upon contact, thereby reducing nematode populations and enhancing plant health.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chemical controls are used to kill nematodes, then nematode populations are reduced, but beneficial microorganisms are disrupted
Solution Approach 1:
The patent applies this principle by using a toxin produced by a beneficial microorganism (Bacillus thuringiensis) to control harmful nematodes. The beneficial microbe is engineered to produce a nematicidal toxin that specifically targets nematodes while leaving other beneficial microorganisms unaffected, thus converting the potential harm of chemical pesticides into a beneficial biological control mechanism.
Solution Approach 2:
The patent uses an engineered beneficial microorganism as an intermediary between the plant and the nematode pest. Instead of direct chemical contact between pesticide and nematode, the beneficial microbe serves as a mediator that delivers the nematicidal toxin specifically to nematodes through its natural infection process, thereby protecting other beneficial microorganisms in the ecosystem.
2Reliability
If conventional breeding is used to develop resistant soybean varieties, then resistance to certain nematodes may be achieved, but the process is slow and limited by lack of appropriate germplasm
Solution Approach 1:
The patent replaces the mechanical/conventional breeding system with a genetic engineering approach. Instead of relying on slow sexual crossing and selection processes, the invention directly introduces a functional gene (cry14) into the soybean genome, achieving nematode resistance in a single generation without the time-consuming steps of conventional breeding.
Solution Approach 2:
The patent applies preliminary action by pre-engineering the resistance trait into the soybean variety before field deployment. The cry14 gene is introduced and expressed in the plant, providing immediate nematode resistance without requiring generations of breeding and selection, thus eliminating the time loss associated with conventional breeding programs.
3Object-affected harmful factors
If no resistant varieties are available, then farmers must rely on chemical controls, but these are non-selective and harm the environment
Solution Approach 1:
The patent converts the harm caused by non-selective chemical pesticides into a benefit by using a selective biological control agent. The engineered beneficial microorganism produces a toxin that specifically targets nematodes while sparing other organisms, thus protecting the environment while still achieving effective nematode control.
Solution Approach 2:
The patent changes the selectivity parameter of the control agent. Instead of using broad-spectrum chemical pesticides that affect all microorganisms, the invention introduces a biologically specific toxin that only affects nematodes, thereby changing the selectivity from non-selective to highly selective and reducing environmental harm.
Data Source
AI summary
Compositions and methods for conferring nematicidal activity to bacteria, plants, plant cells, tissues and seeds are provided. In particular, methods for killing or controlling a nematode pest population, particularly a Pratylenchus spp., e.g., Pratylenchus brachyurus, root knot nematode, reniform nematode, or Lance nematode population, are provided. The methods include contacting the nematode pest with a pesticidally-effective amount of a polypeptide comprising a nematicidal toxin, particularly a nematicidal toxin active against a Pratylenchus spp. nematode, e.g. Pratylenchus brachyurus. Further included are methods for increasing yield in plants by expressing the toxin of the invention.