title: An Allelic Series of bak1 Mutations Differentially Alter bir1 Cell Death, Immune Response, Growth, and Root Development Phenotypes in Arabidopsis thaliana.
abstract: Receptor-like kinases (RLKs) mediate cell-signaling pathways in Arabidopsis thaliana, including those controlling growth and development, immune response, and cell death. The RLK coreceptor BRI1-ASSOCIATED KINASE-1 (BAK1) partners with multiple ligand-binding RLKs and contributes to their signaling in diverse pathways. An additional RLK, BAK1-INTERACTING RECEPTOR-1 (BIR1), physically interacts with BAK1, and loss-of-function mutations in BIR1 display constitutive activation of cell death and immune response pathways and dwarfism and a reduction in lateral root number. Here we show that bir1 plants display defects in primary root growth, characterize bir1 lateral root defects, and analyze expression of BIR1 and BAK1 promoters within the root. Using an allelic series of bak1 mutations, we show that loss of BAK1 function in immune response pathways can partially suppress bir1 cell death, immune response, and lateral root phenotypes and that null bak1 alleles enhance bir1 primary root phenotypes. Based on our data, we propose a model in which BIR1 functions to regulate BAK1 participation in multiple pathways.
authors.affiliation: Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Wierzba
authors.affiliation: Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721 School of Plant Sciences, University of Arizona, Tucson, Arizona 85721 fetax@email.arizona.edu.
authors.forename: Frans E
authors.identifier: http://orcid.org/0000-0002-1386-3310
authors.initials: FE
authors.lastname: Tax
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D004843:Epistasis, Genetic; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D007109:Immunity / Q000235:genetics*; D009154:Mutation; D010641:Phenotype; D018517:Plant Roots / Q000502:physiology*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; C463660:BAK1 protein, Arabidopsis; C570514:BIR1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases
keywords: cell death; genetic suppression; lateral roots; receptor-like kinases