RNA-based antiviral for Plant Virus

Prelims (GS I) - General Science| Current events of national and international importance.

Mains (GS III) – Science and Technology- developments and their applications and effects in everyday life.

Why in news?

Researchers recently reported developing an RNA-based antiviral agent that confers strong protection against cucumber mosaic virus (CMV).

Plant virus – It is a microscopic, infectious agent that causes diseases in plants.
It destroys a significant portion of annual crops worldwide.
Unlike bacteria or fungi, viruses cannot be controlled with pesticides or fungicides.
Cucumber Mosaic Virus (CMV)
CMV is a plant virus that infects more than 1,200 plant species, including critical food crops like cucumbers, squash, and cereals, and medicinal plants.
Spread through - sap-sucking insects called aphids.
Effects - Infected plants develop mosaic discoloration, stunted growth, and commercially unviable fruits.
Severity - Nearly 90 aphid species are capable of transmitting CMV, making outbreaks difficult to contain.

In India, CMV causes 25-30% yield losses in banana plantations.

Current RNA-based Crop Protection Techniques

RNA Silencing – It is a natural defense mechanism in plants.
When a virus infects a plant, it introduces double-stranded RNA (dsRNA).
The plant responds by activating Dicer-like enzymes (DCLs), which slice the dsRNA into small fragments called small interfering RNAs (siRNAs).
These siRNAs guide the plant's defense system to recognize and destroy viral RNA.
- Limitations – Not all siRNAs are effective, and some plant viruses can mutate rapidly.
Host-induced gene silencing (HIGS) – It works by genetically modifying plants to produce virus-fighting dsRNA in their cells.
- Limitations - High production costs.
Spray-induced gene silencing (SIGS) - More flexible alternative to HIGS where plants are treated with RNA sprays instead of being genetically modified.
- Limitations - Traditional dsRNA Spray formulations produce a random mix of siRNAs, and many are ineffective.

Key Findings of the Research

Researchers first screened and identified the most potent siRNAs against CMV.
These specially selected siRNA bind to the virus’s genetic material to trigger a stronger antiviral response.
Then they designed effective dsRNA (e-siRNAs) enriched with highly functional siRNA.
These e-siRNAs were assembled into dsRNA constructs for more targeted protection.
CMV infected plants treated with the enhanced siRNA had almost 80% lower viral load.
The new dsRNA formulation outperformed traditional dsRNA and it is effective against multiple CMV strains.

Advantages of the New Approach

More precise targeting of viral particles of the most vulnerable genetic regions.
Stronger defense by targeting multiple regions of viral genome simultaneously.
The effective dsRNA can be redesigned in about a month to target new viral strains.

Reference

The Hindu| RNA-based antiviral