Assertion: Tobacco plant yield is highly reduced because of damage to roots.
Reason : Nematode Meloidogyne incognita infects the root.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) – Both Assertion (A) and Reason (R) are correct and R is the correct explanation of A.
Several nematodes parasitise a wide variety of plants and animals including human beings. A nematode Meloidegyne incognitia infects the roots of tobacco plants and causes a great reduction in yield.
A novel strategy was adopted to prevent this infestation which was based on the process of RNA interference (RNAi). RNAi takes place in all eukaryotic organisms as a method of cellular defense. This method involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA (silencing). The source of this complementary RNA could be from an infection by viruses having RNA genomes or mobile genetic elements (transposons) that replicate via an RNA intermediate.