title: Identification of Regions in the Receiver Domain of the ETHYLENE RESPONSE1 Ethylene Receptor of Arabidopsis Important for Functional Divergence.
abstract: Ethylene influences the growth and development of Arabidopsis (Arabidopsis thaliana) via five receptor isoforms. However, the ETHYLENE RESPONSE1 (ETR1) ethylene receptor has unique, and sometimes contrasting, roles from the other receptor isoforms. Prior research indicates that the receiver domain of ETR1 is important for some of these noncanonical roles. We determined that the ETR1 receiver domain is not needed for ETR1's predominant role in mediating responses to the ethylene antagonist, silver. To understand the structure-function relationship underlying the unique roles of the ETR1 receiver domain in the control of specific traits, we performed alanine-scanning mutagenesis. We chose amino acids that are poorly conserved and are in regions predicted to have altered tertiary structure compared with the receiver domains of the other two receptors that contain a receiver domain, ETR2 and ETHYLENE INSENSITIVE4. The effects of these mutants on various phenotypes were examined in transgenic, receptor-deficient Arabidopsis plants. Some traits, such as growth in air and growth recovery after the removal of ethylene, were unaffected by these mutations. By contrast, three mutations on one surface of the receiver domain rendered the transgene unable to rescue ethylene-stimulated nutations. Additionally, several mutations on another surface altered germination on salt. Some of these mutations conferred hyperfunctionality to ETR1 in the context of seed germination on salt, but not for other traits, that correlated with increased responsiveness to abscisic acid. Thus, the ETR1 receiver domain has multiple functions where different surfaces are involved in the control of different traits. Models are discussed for these observations.
authors.affiliation: Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996.
authors.forename: Arkadipta
authors.initials: A
authors.lastname: Bakshi
authors.affiliation: Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996.
authors.forename: Rebecca L
authors.identifier: http://orcid.org/0000-0002-3309-8185
authors.initials: RL
authors.lastname: Wilson
authors.affiliation: Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996.
authors.forename: Randy F
authors.initials: RF
authors.lastname: Lacey
authors.affiliation: Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996.
authors.forename: Heejung
authors.initials: H
authors.lastname: Kim
authors.affiliation: Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996.
authors.forename: Sai Keerthana
authors.initials: SK
authors.lastname: Wuppalapati
authors.affiliation: Genome Science and Technology Program (A.B., B.M.B.) and Department of Biochemistry, Cellular, and Molecular Biology (R.L.W., R.F.L., H.K., S.K.W., B.M.B.), University of Tennessee, Knoxville, Tennessee 37996 bbinder@utk.edu.
authors.forename: Brad M
authors.identifier: http://orcid.org/0000-0002-8172-2034
authors.initials: BM
authors.lastname: Binder
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D005030:Ethylenes / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism*; D030821:Plants, Genetically Modified; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; C494590:ETR1 protein, Arabidopsis; D005030:Ethylenes; D010937:Plant Growth Regulators; D020033:Protein Isoforms; D011956:Receptors, Cell Surface; D000040:Abscisic Acid; C036216:ethylene