103. For engineering virus resistance in plants, which one of the following viral components is commonly
targeted?
(1) coat protein
(2) replication protein
(3) satellite RNA
(4) movement protein
🌿 Engineering Virus Resistance in Plants: Targeting the Coat Protein
Plant viruses are a major threat to global agriculture, causing significant crop losses and impacting food security. Genetic engineering has become a vital strategy to protect plants from viral infections. Among various viral components, the coat protein is most commonly targeted to develop virus-resistant plants.
✅ Correct Answer:
(1) Coat protein
🦠 What Is the Coat Protein in Viruses?
The coat protein (CP) is a structural protein that encases the viral genome, offering protection and playing a role in:
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Virus particle stability
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Host recognition and infection
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Movement of the virus within the host
Because it’s essential for viral replication, packaging, and spread, it makes an ideal target for genetic interference.
🔬 Coat Protein-Mediated Resistance: How It Works
This strategy is based on pathogen-derived resistance (PDR), where a viral gene (usually CP) is inserted into the plant genome. Here’s how it protects the plant:
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Expression of the viral coat protein gene in the plant triggers:
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RNA interference (RNAi) mechanism
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Post-transcriptional gene silencing (PTGS)
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These mechanisms degrade viral RNA upon infection.
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This prevents virus replication and spread, leading to resistance.
🌾 Examples of CP-Mediated Resistance
This method has been successful against several plant viruses:
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Papaya ringspot virus (PRSV) – resistance in genetically modified papaya.
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Potato virus Y (PVY) – resistance in engineered potatoes.
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Tomato mosaic virus (ToMV) – resistance in tomato plants.
📋 Comparison of Viral Targets
| Viral Component | Role in Virus Lifecycle | Resistance Strategy | Commonly Targeted? |
|---|---|---|---|
| Coat Protein | Protects genome, host entry | RNA silencing, protein interference | ✅ Yes |
| Replication Protein | Viral RNA synthesis | Complex to target; variable across strains | ❌ Less common |
| Satellite RNA | Accessory molecules | Limited scope | ❌ Rare |
| Movement Protein | Helps virus spread in plant | Sometimes targeted | ❌ Less frequent |
🧬 Why Coat Protein Is the Best Target
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Conserved structure across many virus strains
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Easy to express in transgenic plants
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Triggers strong RNAi-based immunity
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Already proven successful in field crops
🧪 Key Takeaway
To engineer virus resistance in plants, the coat protein is the most effective and widely used target. Its essential role in viral infection and compatibility with RNA-silencing pathways make it a reliable choice for developing virus-resistant genetically modified (GM) crops.
Would you like a visual diagram of this genetic engineering process or details on biosafety evaluations?
