Which method of defence is employed to protect against root knot disease by nematodes ?

Options

A. RNA interference
B. Insertional inactivation
C. PCR
D. Elution

Answer

**Step-by-Step Solution:**

1. **Understanding Nematodes**: Nematodes are plant-parasitic organisms that can cause root knot disease by forming knots in the root system of infected plants. This leads to reduced crop yield.

2. **Mechanism of Infection**: When nematodes invade the plant, they insert their messenger RNA (mRNA) into the plant cells. This mRNA is responsible for synthesizing proteins that facilitate the infection process.

3. **Defense Mechanism**: To combat this infection, a method called RNA interference (RNAi) is employed. RNAi is a biological process where double-stranded RNA (dsRNA) is introduced into the plant cells.

4. **Action of RNA Interference**: The introduced dsRNA targets the nematode's mRNA. It breaks down the mRNA into small fragments, preventing the synthesis of the proteins necessary for the nematode's infection.

5. **Outcome**: By halting the protein synthesis in the nematodes, the RNA interference method effectively protects the plants from root knot disease, thereby preventing further damage and maintaining crop yield.

6. **Conclusion**: The method of defense employed against root knot disease caused by nematodes is RNA interference, which disrupts the nematode's ability to infect the plant by targeting its mRNA.

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