Dear student,
In RNA interference complementary RNA binds to the mRNA and prevents its expression into protein. RNAi method is used to prevent infection of nematode Meloidegyne incognita in the roots of tobacco plant. Nematode specific genes are introduced into the host which forms RNA which are complementary to each other forms bends and forms double stranded RNA causing RNA interference. mRNA of the nematode becomes silenced and can not survive in the host thus preventing the infection of nematode in the roots of tobacco plant.
Regards