Host-generated double stranded RNA induces RNAi in plant-parasitic nematodes and protects the host from infection

Abstract

Several species of nematodes parasitize a wide variety of plants and animals, including human. Human parasites such as the gut worm Ascaris lumbricoides, hook worms Ancylostoma duodenale and Necator americanus, and the causative agents of the lymphatic filariasis Wuchereria bancrofti and Brugia malayi infect and severely affect the health of about half the world’s population [1]. Similarly, gastrointestinal nematodes (Osterta�gia ostertagi) and liver fluke (Fasciola hepatica) infect livestock leading to considerable yield loss in animal husbandary [2]. The plant parasites such as the root-knot (Meloidogyne spp.) and cyst (Heterodera and Globodera spp.) nematodes cause significant damage to important crop plants such as legumes, vegetables and cereals in most parts of the world. Annual crop loss due to plant-parasitic nematodes is estimated to be over $ 125 billion [3]. Despite this enormous impact on world-wide agriculture, currently there is no effective and environmentally safe method available to prevent or treat plant nematode infections [3]. One of the main reasons for this is our limited understanding of the functions of nematode’s genes. Since these organisms require a suitable host for their growth and proliferation, it is nearly impossible to culture them in the laboratory. Because of this, it has not been possible to use the traditional genetic tools, which are widely used to determine gene function in the free-living model organisms, for the functional characterization of parasitic nematode genes.