title: A root-knot nematode-secreted protein is injected into giant cells and targeted to the nuclei.
abstract: Root-knot nematodes (RKNs) are obligate endoparasites that maintain a biotrophic relationship with their hosts over a period of several weeks and induce the differentiation of root cells into specialized feeding cells. Nematode effectors synthesized in the oesophageal glands and injected into the plant tissue through the syringe-like stylet certainly play a central role in these processes. In a search for nematode effectors, we used comparative genomics on expressed sequence tag (EST) datasets to identify Meloidogyne incognita genes encoding proteins potentially secreted upon the early steps of infection. We identified three genes specifically expressed in the oesophageal glands of parasitic juveniles that encode predicted secreted proteins. One of these genes, Mi-EFF1 is a pioneer gene that has no similarity in databases and a predicted nuclear localization signal. We demonstrate that RKNs secrete Mi-EFF1 within the feeding site and show Mi-EFF1 targeting to the nuclei of the feeding cells. RKNs were previously shown to secrete proteins in the apoplasm of infected tissues. Our results show that nematodes sedentarily established at the feeding site also deliver proteins within plant cells through their stylet. The protein Mi-EFF1 injected within the feeding cells is targeted at the nuclei where it may manipulate nuclear functions of the host cell.
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Maëlle
authors.initials: M
authors.lastname: Jaouannet
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Perfus-Barbeoch
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Emeline
authors.initials: E
authors.lastname: Deleury
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Magliano
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Engler
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Paulo
authors.initials: P
authors.lastname: Vieira
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Etienne G J
authors.initials: EGJ
authors.lastname: Danchin
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Martine Da
authors.initials: MD
authors.lastname: Rocha
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Coquillard
authors.affiliation: INRA UMR 1301, CNRS UMR 6243, Université de Nice Sophia Antipolis, 400 route des Chappes, F-06903 Sophia-Antipolis, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Abad
authors.affiliation: INRA, Université Aix-Marseille, UMR1163 Biotechnologie des Champignons Filamenteux, F-13288 Marseille, France.
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Rosso
mesh_terms: D000818:Animals; D020224:Expressed Sequence Tags; D005260:Female; D023281:Genomics; D015726:Giant Cells / Q000378:metabolism; D015801:Helminth Proteins / Q000378:metabolism*; D006790:Host-Parasite Interactions; D018551:Solanum lycopersicum; D019913:Nuclear Localization Signals / Q000235:genetics; D018517:Plant Roots / Q000469:parasitology* / Q000502:physiology; D014431:Tylenchoidea / Q000235:genetics / Q000502:physiology*
chemical_list: D015801:Helminth Proteins; D019913:Nuclear Localization Signals