A secreted root-knot nematode effector that disrupts the plant actin cytoskeleton
C. GLEASON (1), N. Leelarasamee (1) (1) Georg August University, Germany

Plant parasitic nematodes are one of the most economically damaging pathogens, causing estimated losses of over 1 billion dollars per year worldwide. Of the plant parasitic nematodes, root knot nematodes (Meloidogyne spp) have a very large host range and can be serious pests on major food crops. In order to establish a successful infection, root-knot nematodes induce feeding sites within the root. These feedings sites are derived from plant cells that undergo DNA replication without cytokinesis, and hence, they are termed “giant cells.” During giant cell development, the cell undergoes a dynamic re-organization of its cytoskeleton, but the mechanism behind this process is largely unknown. Here we show evidence that the root-knot nematode produces a profilin isoform called MiPFN1 that is involved in parasitism. Profilins are actin binding proteins that can regulate actin dynamics. By using in situ hybridization, we have found that the MiPFN1 transcript localizes to the nematode glands, indicating that MiPFN1 is likely secreted by the nematode into the plant. A yeast-two-hybrid analysis showed that MiPFN1 can interact with plant actins. In addition, when MiPFN1 is ectopically expressed in Arabidopsis, the plants showed a small, but significant increase in nematode susceptibility. Interestingly when MiPFN1 is expressed in plant protoplasts, the actin cytoskeletal structure is altered. We hypothesize that root-knot nematodes are secreting MiPFN1 to manipulate the plant cytoskeleton and facilitate the formation of giant cells.

Abstract Number: P9-256
Session Type: Poster