Engineering herbicide resistance in transgenic plants — which strategic approaches are used?

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:

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