Transgenic insect resistance in crop plants can be engineered by introducing which types of genes into the plant genome?

Introduction / Context:
Modern plant biotechnology offers multiple strategies to protect crops from insect pests. Beyond the well-known Bt toxins, several other gene classes have been used to impair insect feeding and survival, reducing the need for broad-spectrum chemical insecticides.

Given Data / Assumptions:

• Goal: endogenous plant expression of molecules that harm target insects.
• Mechanisms include pore-forming toxins, digestive disruption, and antifeedants.
• Stacking traits can broaden spectrum and slow resistance evolution.

Concept / Approach:
Bt proteins bind to midgut receptors in susceptible insects, forming pores and causing death. Protease inhibitors reduce nutrient acquisition by inhibiting gut proteases. Genes enabling biosynthesis of certain defensive secondary metabolites (e.g., proteinase inhibitors, lectins, or terpenoid pathways) can also deter or kill pests. Together, these approaches constitute a toolkit for transgenic resistance.

Step-by-Step Solution:

Verification / Alternative check:
Commercialized crops (e.g., Bt cotton, Bt maize) and published studies on protease inhibitors and lectins support the multi-pronged approach.

Why Other Options Are Wrong:

• A, B, C each describe one valid method but not the full set.
• E is incorrect; multiple non-Bt strategies exist and have been tested.

Common Pitfalls:
Assuming Bt is the only viable option or ignoring resistance management; gene stacking and refuges are essential.

Final Answer:
All of the above