In higher plants and insects, RNA silencing is an evolutionarily conserved sequence-specific gene-inactivation system that also serves as an antiviral mechanism.
Antiviral RNA silencing is overcome by viruses expressing silencing-suppressor proteins that can inhibit the host's antiviral silencing process.
RNAi is the basis of virus-induced gene silencing (VIGS) in plants, implying that it plays a key role in disease resistance.
The nematode parasite in the host plant is killed using an RNA silencing method.
For example, Meloidogyne incognita, a nematode, can infect the roots of tobacco plants.