title: The rice immune receptor XA21 recognizes a tyrosine-sulfated protein from a Gram-negative bacterium.
abstract: Surveillance of the extracellular environment by immune receptors is of central importance to eukaryotic survival. The rice receptor kinase XA21, which confers robust resistance to most strains of the Gram-negative bacterium Xanthomonas oryzae pv. oryzae (Xoo), is representative of a large class of cell surface immune receptors in plants and animals. We report the identification of a previously undescribed Xoo protein, called RaxX, which is required for activation of XA21-mediated immunity. Xoo strains that lack RaxX, or carry mutations in the single RaxX tyrosine residue (Y41), are able to evade XA21-mediated immunity. Y41 of RaxX is sulfated by the prokaryotic tyrosine sulfotransferase RaxST. Sulfated, but not nonsulfated, RaxX triggers hallmarks of the plant immune response in an XA21-dependent manner. A sulfated, 21-amino acid synthetic RaxX peptide (RaxX21-sY) is sufficient for this activity. Xoo field isolates that overcome XA21-mediated immunity encode an alternate raxX allele, suggesting that coevolutionary interactions between host and pathogen contribute to RaxX diversification. RaxX is highly conserved in many plant pathogenic Xanthomonas species. The new insights gained from the discovery and characterization of the sulfated protein, RaxX, can be applied to the development of resistant crop varieties and therapeutic reagents that have the potential to block microbial infection of both plants and animals.
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA. ; Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Rory N
authors.initials: RN
authors.lastname: Pruitt
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA. ; Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. ; The Australian National University, Research School of Biology, Acton ACT 2601, Australia.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schwessinger
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA. ; Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Joe
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Thomas
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Furong
authors.initials: F
authors.lastname: Liu
authors.affiliation: Centre for Plant Molecular Biology, University of Tübingen, 72074 Tübingen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Albert
authors.affiliation: Centre for Plant Molecular Biology, University of Tübingen, 72074 Tübingen, Germany.
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Robinson
authors.affiliation: Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Leanne Jade G
authors.initials: LJ
authors.lastname: Chan
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Dee Dee
authors.initials: DD
authors.lastname: Luu
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Huamin
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Ofir
authors.initials: O
authors.lastname: Bahar
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Arsalan
authors.initials: A
authors.lastname: Daudi
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: David
authors.initials: D
authors.lastname: De Vleesschauwer
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Caddell
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Weiguo
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Xiuxiang
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, USA.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.affiliation: Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Joshua L
authors.initials: JL
authors.lastname: Heazlewood
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA. ; Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Deling
authors.initials: D
authors.lastname: Ruan
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Dipali
authors.initials: D
authors.lastname: Majumder
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA. ; Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Mawsheng
authors.initials: M
authors.lastname: Chern
authors.affiliation: Interfaculty Institute of Biochemistry, University of Tübingen, 72074 Tübingen, Germany.
authors.forename: Hubert
authors.initials: H
authors.lastname: Kalbacher
authors.affiliation: Council of Scientific & Industrial Research (CSIR)-Institute of Microbial Technology, Chandigarh 160036, India.
authors.forename: Samriti
authors.initials: S
authors.lastname: Midha
authors.affiliation: Council of Scientific & Industrial Research (CSIR)-Institute of Microbial Technology, Chandigarh 160036, India.
authors.forename: Prabhu B
authors.initials: PB
authors.lastname: Patil
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India.
authors.forename: Ramesh V
authors.initials: RV
authors.lastname: Sonti
authors.affiliation: Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Petzold
authors.affiliation: Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, USA. ; Department of Chemistry, University of California, Irvine, Irvine, CA 92697, USA.
authors.forename: Chang C
authors.initials: CC
authors.lastname: Liu
authors.affiliation: Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Brodbelt
authors.affiliation: Centre for Plant Molecular Biology, University of Tübingen, 72074 Tübingen, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Felix
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA 95616, USA. ; Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Pamela C
authors.initials: PC
authors.lastname: Ronald
keywords: Bacteria; Rice; immune receptors