Engineering herbicide resistance in transgenic plants — which strategic approaches are used?
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AAlter the herbicide target protein so it becomes insensitive to the herbicide
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BOverproduce the target enzyme to overcome inhibition
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CIntroduce a pathway or enzyme that detoxifies the herbicide molecule
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DAll of the above
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ENone of the above
Answer
Correct Answer: All of the above
Explanation
Introduction / Context:Herbicide resistance traits can be engineered using multiple strategies, each addressing a different point in the herbicide–plant interaction: target modification, target overproduction, or metabolism-based detoxification.
Given Data / Assumptions:
- Target enzymes include EPSPS (glyphosate) or ALS (sulfonylureas/imazapyrs).
- Detox enzymes include PAT/Bar (glufosinate) or other degradative enzymes.
- Overexpression sometimes buffers partial inhibition.
Concept / Approach:
All listed strategies have precedents: insensitive EPSPS mutations, ALS variants, or overexpression; and detoxification by acetyltransferases or oxygenases. Therefore, the comprehensive answer is that all can be used depending on herbicide mode of action.
Step-by-Step Solution:
List known resistance mechanisms.Match each to real-world examples.Conclude that multiple avenues are valid.Select “All of the above.”Verification / Alternative check:
Commercial crops exhibit target-site mutations (EPSPS, ALS) and detoxification (bar/pat) strategies.
Why Other Options Are Wrong:
Each individual option is correct, so “None” and single-option choices are incomplete.
Common Pitfalls:
Assuming one universal method; herbicides act via distinct targets requiring tailored strategies.
Final Answer:
All of the above