title: Regulation of cell death and innate immunity by two receptor-like kinases in Arabidopsis.
abstract: Upon recognition of bacterial flagellin, the plant receptor FLS2 heterodimerizes with brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1) and activates plant defense responses. Because constitutive activation of defense responses is detrimental, plant resistance signaling pathways must be negatively controlled, although the mechanisms involved are unclear. We identified Arabidopsis BIR1 as a BAK1-interacting receptor-like kinase. Knocking out BIR1 leads to extensive cell death, activation of constitutive defense responses, and impairment in the activation of MPK4, a negative regulator of plant resistance (R) protein signaling, by flagellin. sobir1-1, a mutant obtained in a screen for suppressors of the bir1-1 phenotype, rescued cell death observed in bir1-1. SOBIR1 encodes another receptor-like kinase whose overexpression activates cell death and defense responses. Our data suggest that BIR1 negatively regulates multiple plant resistance signaling pathways, one of which is the SOBIR1-dependent pathway identified here.
authors.affiliation: College of Biological Sciences, China Agricultural University, Beijing 100094, China.
authors.forename: Minghui
authors.initials: M
authors.lastname: Gao
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Xu
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Ding
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Zhang
authors.forename: Dongling
authors.initials: D
authors.lastname: Bi
authors.forename: Yu Ti
authors.initials: YT
authors.lastname: Cheng
authors.forename: She
authors.initials: S
authors.lastname: Chen
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Yuelin
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000502:physiology*; D017360:Arabidopsis / Q000276:immunology*; D029681:Arabidopsis Proteins / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000276:immunology; D005408:Flagellin / Q000276:immunology; D055786:Gene Knockout Techniques; D007113:Immunity, Innate; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*
chemical_list: D051017:Apoptosis Regulatory Proteins; D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D005408:Flagellin; C463660:BAK1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; C436292:AtMPK4 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases