Cell cycle activation by plant parasitic nematodes

Sedentary nematodes are important pests of crop plants. They are biotrophic parasites that can induce the (re)differentiation of either differentiated or undifferentiated plant cells into specialized feeding cells. This (re)d ifferentiation includes the reactivation of the cell cycle in specific plan t cells finally resulting in a transfer cell-like feeding site. For growth and development the nematodes fully depend on these cells. The mechanisms u nderlying the ability of these nematodes to manipulate a plant for its own benefit are unknown. Nematode secretions are thought to play a key role bot h in plant penetration and feeding cell induction. Research on plant-nemato de interactions is hampered by the minute size of cyst and root knot nemato des, their obligatory biotrophic nature and their relatively long life cycl e. Recently, insights into cell cycle control in Arabidopsis thaliana in co mbination with reporter gene technologies showed the differential activatio n of cell cycle gene promoters upon infection with cyst or root knot nemato des. In this review, we integrate the current views of plant cell fate mani pulation by these sedentary nematodes and made an inventory of possible lin ks between cell cycle activation and local, nematode-induced changes in aux in levels.