Question

The rDNA technology has provided a method to control the nematode parasite Meloidogyne incognita. Explain the principle involved in this technique.

Answer 1

RNA interference (RNAi) is a gene-silencing process that blocks the expression of genes in the parasite when it enters the host's body. This method is used to prevent infestation of roots of tobacco plants by a nematode Meloidogyne incognita. In RNAi, a complementary RNA binds to mRNA to form a dsRNA that cannot translate and hence its expression is blocked. Synthetic neurotransmitants mixed with dsRNA solutions are used for in vitro RNAi in plant-parasitic nematodes with significant success. This introduced DNA which forms both sense and anti-sense RNA. These two strands are complementary to each other bend and form dsRNA leading to RNA interference. mRNA of nematodes is thus silent and the parasite cannot survive in the transgenic host. Thus through this method tobacco plants can be protected from nematode attacks.