title: Polarized Defense Against Fungal Pathogens Is Mediated by the Jacalin-Related Lectin Domain of Modular Poaceae-Specific Proteins.
abstract: Modular proteins are an evolutionary answer to optimize performance of proteins that physically interact with each other for functionality. Using a combination of genetic and biochemical experiments, we characterized the rice protein OsJAC1, which consists of a jacalin-related lectin (JRL) domain predicted to bind mannose-containing oligosaccharides, and a dirigent domain which might function in stereoselective coupling of monolignols. Transgenic overexpression of OsJAC1 in rice resulted in quantitative broad-spectrum resistance against different pathogens including bacteria, oomycetes, and fungi. Overexpression of this gene or its wheat ortholog TAJA1 in barley enhanced resistance against the powdery mildew fungus. Both protein domains of OsJAC1 are required to establish resistance as indicated by single or combined transient expression of individual domains. Expression of artificially separated and fluorescence-tagged protein domains showed that the JRL domain is sufficient for targeting the powdery mildew penetration site. Nevertheless, co-localization of the lectin and the dirigent domain occurred. Phylogenetic analyses revealed orthologs of OsJAC1 exclusively within the Poaceae plant family. Dicots, by contrast, only contain proteins with either JRL or dirigent domain(s). Altogether, our results identify OsJAC1 as a representative of a novel type of resistance protein derived from a plant lineage-specific gene fusion event for better function in local pathogen defense.
authors.affiliation: Department of Plant Physiology, RWTH Aachen University, 52056 Aachen, Germany.
authors.forename: Denise
authors.initials: D
authors.lastname: Weidenbach
authors.affiliation: Department of Plant Physiology, RWTH Aachen University, 52056 Aachen, Germany.
authors.forename: Lara
authors.initials: L
authors.lastname: Esch
authors.affiliation: Department of Plant Physiology, RWTH Aachen University, 52056 Aachen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Möller
authors.affiliation: Plant Reproductive Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, 06466 Stadt Seeland/OT Gatersleben, Germany.
authors.forename: Goetz
authors.initials: G
authors.lastname: Hensel
authors.affiliation: Plant Reproductive Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, 06466 Stadt Seeland/OT Gatersleben, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Kumlehn
authors.affiliation: Center of Life and Food Sciences Weihenstephan, Technische Universität München, 85350 Freising, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Höfle
authors.affiliation: Center of Life and Food Sciences Weihenstephan, Technische Universität München, 85350 Freising, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Hückelhoven
authors.affiliation: Department of Plant Physiology, RWTH Aachen University, 52056 Aachen, Germany. Electronic address: schaffrath@bio3.rwth-aachen.de.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schaffrath
mesh_terms: D000595:Amino Acid Sequence; D060467:Disease Resistance; D005658:Fungi / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D050939:Gene Fusion; D001467:Hordeum / Q000235:genetics / Q000382:microbiology / Q000502:physiology; D012275:Oryza / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology* / Q000502:physiology; D010935:Plant Diseases / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000072417:Protein Domains; D021381:Protein Transport; D013045:Species Specificity
chemical_list: D010940:Plant Proteins
keywords: Rosetta stone protein; barley (Hordeum vulgare); broad-spectrum disease resistance; dirigent; jacalin-related lectin; rice (Oryza sativa)