Question

Silencing of m RNA has been used in producing transgenic plants resistant to
A) Bollworms
B) Nematodes
C) White rusts
D) Bacterial blights

Answer 1

Hint: RNA silencing refers to a family of gene silencing effects by which gene expression is negatively regulated. RNA silencing mechanisms are highly conserved in most eukaryotes.

Complete answer:
A) Bollworms – Cotton crop is generally attacked by the caterpillars of cotton bollworms is Earias vitella and E insulana. They bore into top tender parts of shoots, floral buds & bolls. The affected boll bears holes. They open prematurely and have poor quality of lint. Insecticide treatment on bollworms is very expensive. Genetics have isolated any I Ac gene and cry II Ab gene and incorporated it in the DNA of cotton to develop genetically modified crops, commonly called Bt cotton. This Bt cotton contains Bt toxin gene against cotton boll worms.
B) Nematodes – Specific genes were introduced into tobacco plants via the Agrobacterium vector. The introduced DNA produces bath sense and antisense RNA which are complementary to each other and formed ds RNA. This RNA interference caused silencing of nematodes – specific m RNA and bill nematodes in tobacco root cells.
C) White rust – White rust is a disease of crucifer (Mustard plant). It is caused by Albugo candida.
D) Bacterial blights – It is caused by bacterial pathogen x anthomonas campestris. It is a disease of barley. Bacterial blights infect different crops.

Hence the correct answer is option B, Nematodes.

Note: Nematodes are roundworms, which are closely related to true worms. They have smooth, unsegmented bodies and feed on tiny microscopic plants.