Q.Meloidegyne incognitia is a nematode parasite infects the root of tobacco plants. It's infection can be prevented by biotechnological methods.

Tobacco was made resistant to the root-knot nematode Meloidogyne incognita using RNA interference — the plant is engineered to produce double-stranded RNA that silences a gene essential to the nematode.

a) Strategy: The biotechnological strategy used to protect tobacco from the nematode Meloidogyne incognitia is RNA interference (RNAi).

b) Principle: RNA interference is a method of gene silencing that operates at the mRNA level, based on complementary base-pairing between two RNA strands.

• Specific genes of the nematode Meloidogyne incognitia were identified and introduced into the tobacco plant using Agrobacterium tumefaciens as a vector.
• The introduced DNA was designed so that, once inside the host plant cell, it would be transcribed into both a sense RNA and an anti-sense RNA (i.e., RNA and its complementary copy).
• Since these two RNA strands are complementary to each other, they hybridise to form a double-stranded RNA (dsRNA) within the transgenic host cells.
• This dsRNA triggers the RNA interference pathway, which specifically binds to and silences (degrades/blocks) the corresponding mRNA of the nematode — i.e., an mRNA essential for the nematode's survival/infectivity. …