title: Suppression of bacterial infection in rice by treatment with a sulfated peptide.
abstract: The rice XA21 receptor kinase confers robust resistance to bacterial blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo). A tyrosine-sulfated peptide from Xoo, called RaxX, triggers XA21-mediated immune responses, including the production of ethylene and reactive oxygen species and the induction of defence gene expression. It has not been tested previously whether these responses confer effective resistance to Xoo. Here, we describe a newly established post-inoculation treatment assay that facilitates investigations into the effect of the sulfated RaxX peptide in planta. In this assay, rice plants were inoculated with a virulent strain of Xoo and then treated with the RaxX peptide 2 days after inoculation. We found that post-inoculation treatment of XA21 plants with the sulfated RaxX peptide suppresses the development of Xoo infection in XA21 rice plants. The treated plants display restricted lesion development and reduced bacterial growth. Our findings demonstrate that exogenous application of sulfated RaxX activates XA21-mediated immunity in planta, and provides a potential strategy for the control of bacterial disease in the field.
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA, 95616, USA.|Feedstocks Division, Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors.forename: Tong
authors.initials: T
authors.lastname: Wei
authors.affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA, 95616, USA.|Feedstocks Division, Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors.forename: Mawsheng
authors.initials: M
authors.lastname: Chern
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: Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA, 95616, USA.|Feedstocks Division, Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors.forename: Pamela C
authors.initials: PC
authors.lastname: Ronald
mesh_terms: D060467:Disease Resistance / Q000187:drug effects; D018527:Hydroponics; D012275:Oryza / Q000187:drug effects / Q000254:growth & development / Q000382:microbiology*; D010455:Peptides / Q000494:pharmacology*; D010935:Plant Diseases / Q000382:microbiology*; D013431:Sulfates / Q000494:pharmacology*; D014774:Virulence / Q000187:drug effects; D014867:Water; D014974:Xanthomonas / Q000472:pathogenicity*
chemical_list: D010455:Peptides; D013431:Sulfates; D014867:Water
keywords: XA21-mediated immunity, Xanthomonas oryzae pv. oryzae; bacterial blight disease of rice; post-inoculation treatment; sulfated RaxX