Biotechnological Applications In Agriculture

The strategy of RNA interference (RNAi) was applied to protect tobacco plants from the root-knot nematode Meloidogyne incognita, an example explained in NCERT Class 12, Chapter 11 (Biotechnology and its Applications). Scientists introduced nematode-specific genes into the host plant using Agrobacterium vectors so that both sense and antisense RNA were produced, forming double-stranded RNA. This dsRNA initiated RNAi, silencing the corresponding messenger RNA of the parasite when it fed on the plant, leading to the death or repulsion of the nematode without harming the plant. Helicoverpa armigera is the cotton bollworm, controlled by Bt cry proteins rather than by RNAi in this context, so it is incorrect. Agrobacterium tumefaciens functions as a gene-delivery vector here, not as the pest being targeted. Pseudomonas putida is a bacterium known for bioremediation and the superbug experiments, unrelated to nematode resistance. The elegance of this approach lies in its specificity, because the silencing affects only the nematode transcript that matches the introduced sequence, leaving the plant's own genes and beneficial organisms unaffected. This makes RNAi a targeted alternative to broad-spectrum nematicides. A consistency check supports the answer: RNAi silences a parasite's own essential transcripts, so the target must be the feeding parasitic nematode, which is Meloidogyne incognita.