This project deals with a novel type of genetically determined disease resistance that is specific for Phytophthora. Previously we used phage display to select plant proteins interacting with the Phytophthora infestans RXLR effector IPI-O via the cell attachment motif RGD (Gouget et al. 2006 Plant Physiology) and identified a transmembrane protein in Arabidopsis with an intracellular kinase domain and an extracellular lectin domain with two amino motifs, ASYY and PHPR, that are implicated in binding IPI-O via its RGD motif. This legume-like lectin receptor kinase, named LecRK-I.9, appeared to be crucial for Phytophthora disease resistance in Arabidopsis (Bouwmeester et al. 2011 PLoS Pathogens). Ongoing research focuses on identifying the components of the effector-host target complexes and on mutational analysis of LecRK-I.9 to identify subdomains and motifs that are essential for conferring disease resistance. LecRK-I.9 is a member of a family of 45 LecRKs (Bouwmeester & Govers 2009 JXB). We are currently evaluating the role other LecRKs in disease resistance by screening Arabidopsis LecRK T-DNA mutants in infection assays with a variety of oomycetes, fungi and bacteria pathogenic on Arabidopsis and for their responses to PAMPs and effectors. Knowledge gained in these model pathosystems can then be used to explore the role of LecRK homologs in disease resistance in crop species.