PEST RESISTANCE PLANTS

Pest resistance plants have been created to protect against the nematodes .

The nematode Meloidogyne  incognitia infects the roots of the tobacco plant causing great loss in the production of the tobacco .

Thus a technique is being developed to protect the tobacco roots known as the RNAi or RNA interference.

RNAi takes place in all eukaryotic organs as a method of cellular defence .

This mechanism involves the silencing of the specific mRNA so that the protein synthesis or the gene expression will be prevented .

In this mechanism the nematode specific gene i. e. ds DNA and introduced into the host plants .

These ds DNA synthesizes the ds RNA in the host cells .Then the ds RNA are cleaved into  si RNA , sh RNA and mi RNA by the enzyme DICER .

Whenever the nematode tries to infest the roots of the tobacco plant the fragments of ds RNA binds with the specific mRNA of the nematode to form the compound called RISC .

Thus the formation of RISC dose not allow the translation of mRNA o nematodes for root destruction . As a result the nematode can not destroy the root.