title: The avrRxo1 gene from the rice pathogen Xanthomonas oryzae pv. oryzicola confers a nonhost defense reaction on maize with resistance gene Rxo1.
abstract: Maize lines that contain the single dominant gene Rxo1 exhibit a rapid hypersensitive response (HR) after infiltration with the rice bacterial streak pathogen Xanthomonas oryzae pv. oryzicola, but not with the rice bacterial blight pathogen X. oryzae pv. oryzae. The avirulence effector gene that corresponds to Rxo1, designated avrRxo1, was identified in an X. oryzae pv. oryzicola genomic library. When introduced into X. oryzae pv. oryzae, clones containing avrRxo1 induced an HR on maize with Rxo1, but not on maize without Rxo1. The avrRxo1 gene is 1,266 bp long and shows no significant homology to any database sequences. When expressed in an X. oryzae pv. oryzae hrpC mutant that is deficient in the type III secretion system, avrRxo1 did not elicit the HR, indicating that the avrRxo1-Rxo1 interaction is dependent on type III secretion. Transient expression of avrRxo1 in onion cells after biolistic delivery revealed that the protein product was associated with the plasma membrane. Transient expression in maize lines carrying Rxo1 resulted in cell death, suggesting that AvrRxo1 functions from inside maize cells to elicit Rxo1-dependent pathogen recognition.
authors.affiliation: Department of Plant Pathology, 4024 Throckmorton Plant Sciences Center, Kansas State University, Manhattan 66506-5502, USA.
authors.forename: Bingyu
authors.initials: B
authors.lastname: Zhao
authors.forename: Edna Y
authors.initials: EY
authors.lastname: Ardales
authors.forename: Asuncion
authors.initials: A
authors.lastname: Raymundo
authors.forename: Jianfa
authors.initials: J
authors.lastname: Bai
authors.forename: Harold N
authors.initials: HN
authors.lastname: Trick
authors.forename: Jan E
authors.initials: JE
authors.lastname: Leach
authors.forename: Scot H
authors.initials: SH
authors.lastname: Hulbert
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D007113:Immunity, Innate / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D012275:Oryza / Q000382:microbiology*; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D025941:Protein Interaction Mapping; D014974:Xanthomonas / Q000235:genetics / Q000254:growth & development*; D003313:Zea mays / Q000235:genetics* / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; C489531:avrRxo1 protein, Xanthomonas