title: Arabidopsis thaliana responses to mechanical stimulation do not require ETR1 or EIN2.
abstract: Plants exposed to repetitive touch or wind are generally shorter and stockier than sheltered plants. These mechanostimulus-induced developmental changes are termed thigmomorphogenesis and may confer resistance to subsequent stresses. An early response of Arabidopsis thaliana to touch or wind is the up-regulation of TCH (touch) gene expression. The signal transduction pathway that leads to mechanostimulus responses is not well defined. A role for ethylene has been proposed based on the observation that mechanostimulation of plants leads to ethylene evolution and exogenous ethylene leads to thigmomorphogenetic-like changes. To determine whether ethylene has a role in plant responses to mechanostimulation, we assessed the ability of two ethylene-insensitive mutants, etr1-3 and ein2-1, to undergo thigmomorphogenesis and TCH gene up-regulation of expression. The ethylene-insensitive mutants responded to wind similarly to the wild type, with a delay in flowering, decrease in inflorescence elongation rate, shorter mature primary inflorescences, more rosette paraclades, and appropriate TCH gene expression changes. Also, wild-type and mutant Arabidopsis responded to vibrational stimulation, with an increase in hypocotyl elongation and up-regulation of TCH gene expression. We conclude that the ETR1 and EIN2 protein functions are not required for the developmental and molecular responses to mechanical stimulation.
authors.affiliation: Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005-1892, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Johnson
authors.forename: M L
authors.initials: ML
authors.lastname: Sistrunk
authors.forename: D H
authors.initials: DH
authors.lastname: Polisensky
authors.forename: J
authors.initials: J
authors.lastname: Braam
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins; D002135:Calcium-Binding Proteins / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D010812:Physical Stimulation; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology; D011956:Receptors, Cell Surface / Q000502:physiology; D014732:Vibration; D014919:Wind; D002147:Calmodulin
chemical_list: D029681:Arabidopsis Proteins; D002135:Calcium-Binding Proteins; C083750:ethylene receptors, plant; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C572690:AT5G37780 protein, Arabidopsis; D002147:Calmodulin