title: Ethylene stimulates nutations that are dependent on the ETR1 receptor.
abstract: Ethylene influences a number of processes in Arabidopsis (Arabidopsis thaliana) through the action of five receptors. In this study, we used high-resolution, time-lapse imaging to examine the long-term effects of ethylene on growing, etiolated Arabidopsis seedlings. These measurements revealed that ethylene stimulates nutations of the hypocotyls with an average delay in onset of over 6 h. The nutation response was constitutive in ctr1-2 mutants maintained in air, whereas ein2-1 mutants failed to nutate when treated with ethylene. Ethylene-stimulated nutations were also eliminated in etr1-7 loss-of-function mutants. Transformation of the etr1-7 mutant with a wild-type genomic ETR1 transgene rescued the nutation phenotype, further supporting a requirement for ETR1. Loss-of-function mutations in the other receptor isoforms had no effect on ethylene-stimulated nutations. However, the double ers1-2 ers2-3 and triple etr2-3 ers2-3 ein4-4 loss-of-function mutants constitutively nutated in air. These results support a model where all the receptors are involved in ethylene-stimulated nutations, but the ETR1 receptor is required and has a contrasting role from the other receptor isoforms in this nutation phenotype. Naphthylphthalamic acid eliminated ethylene-stimulated nutations but had no effect on growth inhibition caused by ethylene, pointing to a role for auxin transport in the nutation phenotype.
authors.affiliation: Department of Botany, University of Wisconsin, Madison, Wisconsin 53706, USA. bmbinder@wisc.edu
authors.forename: Brad M
authors.initials: BM
authors.lastname: Binder
authors.forename: Ronan C
authors.initials: RC
authors.lastname: O'Malley
authors.forename: Wuyi
authors.initials: W
authors.lastname: Wang
authors.forename: Tobias C
authors.initials: TC
authors.lastname: Zutz
authors.forename: Anthony B
authors.initials: AB
authors.lastname: Bleecker
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D005030:Ethylenes / Q000494:pharmacology*; D007210:Indoleacetic Acids / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D010937:Plant Growth Regulators / Q000494:pharmacology*; D020033:Protein Isoforms / Q000235:genetics / Q000502:physiology; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology*; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D015398:Signal Transduction / Q000187:drug effects; D014170:Transformation, Genetic; D019076:Transgenes
chemical_list: D029681:Arabidopsis Proteins; C494590:ETR1 protein, Arabidopsis; D005030:Ethylenes; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D020033:Protein Isoforms; D011956:Receptors, Cell Surface; C036216:ethylene