title: The lectin receptor kinase LecRK-I.9 is a novel Phytophthora resistance component and a potential host target for a RXLR effector.
abstract: In plants, an active defense against biotrophic pathogens is dependent on a functional continuum between the cell wall (CW) and the plasma membrane (PM). It is thus anticipated that proteins maintaining this continuum also function in defense. The legume-like lectin receptor kinase LecRK-I.9 is a putative mediator of CW-PM adhesions in Arabidopsis and is known to bind in vitro to the Phytophthora infestans RXLR-dEER effector IPI-O via a RGD cell attachment motif present in IPI-O. Here we show that LecRK-I.9 is associated with the plasma membrane, and that two T-DNA insertions lines deficient in LecRK-I.9 (lecrk-I.9) have a 'gain-of-susceptibility' phenotype specifically towards the oomycete Phytophthora brassicae. Accordingly, overexpression of LecRK-I.9 leads to enhanced resistance to P. brassicae. A similar 'gain-of-susceptibility' phenotype was observed in transgenic Arabidopsis lines expressing ipiO (35S-ipiO1). This phenocopy behavior was also observed with respect to other defense-related functions; lecrk-I.9 and 35S-ipiO1 were both disturbed in pathogen- and MAMP-triggered callose deposition. By site-directed mutagenesis, we demonstrated that the RGD cell attachment motif in IPI-O is not only essential for disrupting the CW-PM adhesions, but also for disease suppression. These results suggest that destabilizing the CW-PM continuum is one of the tactics used by Phytophthora to promote infection. As countermeasure the host may want to strengthen CW-PM adhesions and the novel Phytophthora resistance component LecRK-I.9 seems to function in this process.
authors.affiliation: Laboratory of Phytopathology, Plant Sciences Group, Wageningen University, Wageningen, The Netherlands.
authors.forename: Klaas
authors.initials: K
authors.lastname: Bouwmeester
authors.forename: Mara
authors.initials: M
authors.lastname: de Sain
authors.forename: Rob
authors.initials: R
authors.lastname: Weide
authors.forename: Anne
authors.initials: A
authors.lastname: Gouget
authors.forename: Sofieke
authors.initials: S
authors.lastname: Klamer
authors.forename: Herve
authors.initials: H
authors.lastname: Canut
authors.forename: Francine
authors.initials: F
authors.lastname: Govers
mesh_terms: D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D015870:Gene Expression; D007113:Immunity, Innate; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010641:Phenotype; D055750:Phytophthora infestans / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D010935:Plant Diseases / Q000276:immunology*; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D005656:Fungal Proteins; C112546:IpiO1 protein, Phytophthora infestans; C099543:ATHLECRK protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases