(a) The method adopted to develop nematode resistance in tobacco plant is  RNAi (RNA Interference). It involves the following steps: (i) Disease-causing gene was identified and isolated from the nematode Meloidogyne incognita. This gene is incorporated into the genome of tobacco plant with the help of a suitable vector. (ii) It is introduced in tobacco plant in such a way that both sense and anti-sense mRNA is produced. These RNAs being complementary get paired to form a double-stranded RNA. (iii) This double-stranded RNA induces RNAi in the tobacco plants which neutralize the mRNA of the nematode during actual infection. Thus nematode is unable to live such as transgenic host and therefore the tobacco plant become resistant to the pest. (b) The vector used for introducing the nematode specific gene in tobacco plant is Agrobacterium tumefaciens.