Sedentary endoparasitic nematodes as a model for other plant parasitic nematodes

Plant parasitic nematodes are known to cause a severe reduction in crop yie ld. Recently much effort is being put to engineering new nematode-resistant crop cultivars. Plant parasitic nematodes occur in three widely separated orders: Triplonchida, Dorylaimida and Tylenchida. All triplonchid and doryl aimid plant parasitic nematodes are migratory ectoparasites of roots. Withi n the Tylenchida, several different types of plant parasitism can be recogn ised. The sedentary endoparasites have the most complex interaction with th eir host, and are responsible for the vast majority of the agricultural dam age. This causes most research to be concentrated on two groups of the sede ntary endoparasitic nematodes: cyst- and root-knot nematodes. Both induce s pecialised feeding structures in the vascular cylinder of the plant root. T he mechanism of phytoparasitism of the cyst- and root-knot nematodes is rev iewed, of which some aspects will be applicable to the study of the other p lant parasitic nematodes.