Nematode specific genes were introduced into the tobacco host plant using a vector

The correct option is Agrobacterium.

Step-by-Step Explanation:

To control the infestation of the nematode Meloidogyne incognita in tobacco plants, a novel strategy based on RNA interference (RNAi) is used.

Nematode-specific genes are introduced into the host tobacco plant. The vector used to transfer these genes into the plant genome is Agrobacterium tumefaciens, a soil bacterium known for its natural ability to transfer DNA into plant cells.

Using Agrobacterium vectors, the nematode-specific DNA is introduced into the host plant in such a way that it produces both sense and anti-sense RNA in the host cells. These two complementary RNAs form a double-stranded RNA (dsRNA), which initiates the process of RNA interference, silencing the specific mRNA of the nematode and protecting the tobacco plant from infection.