Answers

Ganpat
Jul 25, 2020

(i) Infestation of tobacco plant can be stopped by using RNA interference (RNAi) process.

Process of RNAi
Process of RNA interference (RNAi) is related with silencing of a specific mRNA. It is a method of cellular defence in all  eukaryotes.
(i) A complementary RNA binds to the mRNA making it double stranded and prevent its translation.
(ii) This complementary RNA could be from an infection by viruses having RNA genomes or mobile genetic elements  (transposons) that replicate via an RNA intermediate.
(iii) Using Agrobacterium vectors, nematode specific genes were introduced into the host plants.
(iv) It produces both sense and anti-sense RNA in the host cells.
(v) These two RNAs being complementary to each other form a double stranded RNA (dsRNA) that initiated RNAi, silencing  the specific mRNA of the nematode.
(vii) Due to this, parasite could not survive in a transgenic host expressing interfering RNA. So, transgenic plant is protected.
(ii) Vector used for introducing the nematode specific gene in tobacco plant is Agrobacterium.