title: Bacterial Outer Membrane Vesicles Induce Plant Immune Responses.
abstract: Gram-negative bacteria continuously pinch off portions of their outer membrane, releasing membrane vesicles. These outer membrane vesicles (OMVs) are involved in multiple processes including cell-to-cell communication, biofilm formation, stress tolerance, horizontal gene transfer, and virulence. OMVs are also known modulators of the mammalian immune response. Despite the well-documented role of OMVs in mammalian-bacterial communication, their interaction with plants is not well studied. To examine whether OMVs of plant pathogens modulate the plant immune response, we purified OMVs from four different plant pathogens and used them to treat Arabidopsis thaliana. OMVs rapidly induced a reactive oxygen species burst, medium alkalinization, and defense gene expression in A. thaliana leaf discs, cell cultures, and seedlings, respectively. Western blot analysis revealed that EF-Tu is present in OMVs and that it serves as an elicitor of the plant immune response in this form. Our results further show that the immune coreceptors BAK1 and SOBIR1 mediate OMV perception and response. Taken together, our results demonstrate that plants can detect and respond to OMV-associated molecules by activation of their immune system, revealing a new facet of plant-bacterial interactions.
authors.affiliation: 1 Department of Plant Pathology and Weed Science, Agricultural Research Organization, Volcani Center, POB 6, Bet-Dagan, 502500, Israel;
authors.forename: Ofir
authors.initials: O
authors.lastname: Bahar
authors.affiliation: 1 Department of Plant Pathology and Weed Science, Agricultural Research Organization, Volcani Center, POB 6, Bet-Dagan, 502500, Israel;|2 The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel;
authors.forename: Gideon
authors.initials: G
authors.lastname: Mordukhovich
authors.affiliation: 3 Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, U.S.A.;
authors.forename: Dee Dee
authors.initials: DD
authors.lastname: Luu
authors.affiliation: 3 Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, U.S.A.;|4 Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, U.S.A.; and.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schwessinger
authors.affiliation: 3 Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, U.S.A.;
authors.forename: Arsalan
authors.initials: A
authors.lastname: Daudi
authors.affiliation: 5 University Tübingen, 72076 Tübingen, Germany.
authors.forename: Anna Kristina
authors.initials: AK
authors.lastname: Jehle
authors.affiliation: 5 University Tübingen, 72076 Tübingen, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Felix
authors.affiliation: 3 Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, U.S.A.;|4 Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, U.S.A.; and.
authors.forename: Pamela C
authors.initials: PC
authors.lastname: Ronald
mesh_terms: D017360:Arabidopsis / Q000276:immunology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D002462:Cell Membrane / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000276:immunology; D010935:Plant Diseases / Q000276:immunology*
chemical_list: D029681:Arabidopsis Proteins