Plant virus resistance strategies: Which approach has been widely and successfully used to provide resistance against plant viruses in transgenic crops?

Introduction / Context:
Plant viruses cause significant yield losses. Transgenic resistance has followed several routes, and one of the earliest and most widely validated is coat protein–mediated resistance (CPMR), wherein the plant expresses the virus CP gene to interfere with infection processes.

Given Data / Assumptions:

• Goal is broad adoption and proven efficacy in multiple crops.
• Resistance should be specific to the target virus or closely related strains.

Concept / Approach:
CPMR can provide protection by impeding uncoating, assembly, or systemic movement. It is sequence-dependent and often provides strain-specific resistance, sometimes extending to related viruses. This strategy has been deployed in papaya (PRSV), squash, and other crops, significantly reducing disease incidence.

Step-by-Step Solution:

Verification / Alternative check:
Field success stories include PRSV-resistant papaya that saved the Hawaiian papaya industry, demonstrating the practicality and durability of CPMR under real-world conditions.

Why Other Options Are Wrong:

• Bacterial “virus-resistance” genes: not a standard source for plant antiviral resistance.
• Engineering vectors: technologically and ecologically complex, not mainstream.
• Nonspecific RNases or general stress proteins: risk detrimental effects and lack specificity.

Common Pitfalls:
Confusing CPMR with RNA silencing–based approaches; both exist, but CPMR is the classic, widely used method highlighted here.

Final Answer:
Expressing virus coat protein (CP) genes in the plant (coat-protein–mediated resistance)