Question

Tobacco plants resistance to a nematode has been developed by the introduction of DNA that produces (in host cells)
(a)A particular hormone
(b)An antifeedant
(c)A toxic protein
(d)Both sense and antisense RNA

Answer 1

Hint: Plants transformation is a process in which the DNA from any organism is inserted into the genome of the specific species to facilitate the generation of transgenic plants. One of these transformations is the introduction of certain bacterial DNA in tobacco plants.

Complete answer:
Agrobacterium vector was used to introduce nematode specific genes into tobacco plants. This introduced DNA produced both sense and antisense RNA. These RNAs were complementary to each other and formed dsRNA.

Additional Information: An important technology in the vaccine and pharmaceutical industry is plant transformation and one of those plants that are frequently used in this is Nicotiana tabacum i.e. tobacco plants. It has several advantages such as easy regeneration, a completely sequenced genome, and direct genetic transformation.
The most common transformation of tobacco plants uses Agrobacterium tumefaciens.
This process uses the agrobacterium as vectors that carry a nematode-specific gene which further helps the plant in the production of sense and antisense RNA complementary to nematode functions. A specific catalytic RNA called RNAi or RNA interference is used in genetic engineering. It is called RNA silencing. siRNA (silencing RNA) and miRNA (micro RNA) are the two types of RNA used in this.
Crops engineered through RNAi are successful in protection against pests and parasites, including nematodes.
So, the correct answer is “Option D”.

Note: The RNA interference silences the nematode specific mRNA. This is lethal for the survival of nematodes in the root cells of tobacco. Also, it has other advantages like resistance against certain pests and pathogens. Without such protection, the tobacco plants are highly prone to the disease caused by Globodera tabacum nematode which further causes dramatic stunning of growth, yield loss, and decreases leaf quality.