title: BSK1, a receptor-like cytoplasmic kinase, involved in both BR signaling and innate immunity in Arabidopsis.
abstract: Molecular interaction between powdery mildew fungi and Arabidopsis has been widely used as a model system to study plant immunity. Arabidopsis EDR2 (enhanced disease resistance 2) is a well characterized negative regulator in powdery mildew resistance and mildew-induced cell death. Recently, we showed that a mutation in BSK1 (br-signaling kinase 1), suppressed edr2-mediated disease resistance. (1) And the bsk1-1 single mutant displayed enhanced susceptibility to multiple pathogens, indicating that BSK1 plays important roles in plant immunity. BSK1 is a receptor-like cytoplasmic kinase and localizes on plasma membrane; loss of the membrane localization signaling disrupts BSK1 functions in edr2-mediated resistance. Significantly, BSK1 physically associates with the PAMP receptor FLS2 (flagellin sensing 2) and is required by FLS2-mediated ROS burst. (1) Here we show that disruption of BSK1 membrane localization affects the BSK1-FLS2 interactions, suggesting the membrane association of BSK1 is important for both edr2-mediated signaling and the BSK1-FLS2 complex formation. Previously, it was shown that BSK1 is a substrate of the brassinosteroid (BR) receptor BRI1 (brassinosteroid insensitive 1) and plays critical roles in BR signaling. (2) Further exploration of signaling transductions downstream of BSK1-FLS2 complex will not only shed new light on how BSK1 regulates plant immunity, but may also help to dissect the connections between plant growth and defense.
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering; Institute of Genetics and Developmental Biology; Chinese Academy of Sciences; Beijing, PR China; University of Chinese Academy of Sciences; Beijing, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: Shi
authors.forename: Haojie
authors.initials: H
authors.lastname: Yan
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Dingzhong
authors.initials: D
authors.lastname: Tang
mesh_terms: D017360:Arabidopsis / Q000276:immunology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D060406:Brassinosteroids / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology; D007113:Immunity, Innate; D010768:Phosphoserine / Q000378:metabolism; D057865:Plant Immunity; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology*
chemical_list: D029681:Arabidopsis Proteins; D060406:Brassinosteroids; D010768:Phosphoserine; D020794:Receptor Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; C530518:brassinosteroid-signaling kinase1, Arabidopsis
keywords: BR; BSK1; FLS2; disease resistance; powdery mildew