Sense RNA is formed by the genes of nematode which has information for the formation of protein needed for the completion of life cycle of nematode in the roots of tobacco. Antisense RNA is formed by retrotransposons which is associated with sense RNA by hydrogen bonding to form dsRNA. This dsRNA is cleaved into double stranded fragments by dicer protein (Nuclease). Each fragment is associated with RISC which removes the nucleotides of sense RNA by exonuclease activity and leaving the antisense RNA fragments unaffected. When the pest infects the root cells, it releases its sense RNA into root cells. It is associated with antisense RNA fragments through hydrogen bonding. RISC identifies it and cleaves the sense RNA and there by the tobacco plant remain unaffected by the nematode and eventually the nematode life cycle is arrested.