title: Ethylene- and Shade-Induced Hypocotyl Elongation Share Transcriptome Patterns and Functional Regulators.
abstract: Plants have evolved shoot elongation mechanisms to escape from diverse environmental stresses such as flooding and vegetative shade. The apparent similarity in growth responses suggests a possible convergence of the signaling pathways. Shoot elongation is mediated by passive ethylene accumulating to high concentrations in flooded plant organs and by changes in light quality and quantity under vegetation shade. Here, we study hypocotyl elongation as a proxy for shoot elongation and delineate Arabidopsis (Arabidopsis thaliana) hypocotyl length kinetics in response to ethylene and shade. Based on these kinetics, we further investigated ethylene- and shade-induced genome-wide gene expression changes in hypocotyls and cotyledons separately. Both treatments induced a more extensive transcriptome reconfiguration in the hypocotyls compared with the cotyledons. Bioinformatics analyses suggested contrasting regulation of growth promotion- and photosynthesis-related genes. These analyses also suggested an induction of auxin, brassinosteroid, and gibberellin signatures and the involvement of several candidate regulators in the elongating hypocotyls. Pharmacological and mutant analyses confirmed the functional involvement of several of these candidate genes and physiological control points in regulating stress-escape responses to different environmental stimuli. We discuss how these signaling networks might be integrated and conclude that plants, when facing different stresses, utilize a conserved set of transcriptionally regulated genes to modulate and fine-tune growth.
authors.affiliation: Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3584CH Utrecht, The Netherlands (D.D., K.R.S.O., L.A.C.J.V., R.P., R.S.); and Department of Biological Sciences, University of Alberta, Alberta, Canada T6J2E9 (K.R.S.O.).
authors.forename: Debatosh
authors.identifier: 0000-0003-3729-5669
authors.initials: D
authors.lastname: Das
authors.affiliation: Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3584CH Utrecht, The Netherlands (D.D., K.R.S.O., L.A.C.J.V., R.P., R.S.); and Department of Biological Sciences, University of Alberta, Alberta, Canada T6J2E9 (K.R.S.O.).
authors.forename: Kate R
authors.identifier: 0000-0002-1877-6531
authors.initials: KR
authors.lastname: St Onge
authors.affiliation: Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3584CH Utrecht, The Netherlands (D.D., K.R.S.O., L.A.C.J.V., R.P., R.S.); and Department of Biological Sciences, University of Alberta, Alberta, Canada T6J2E9 (K.R.S.O.).
authors.forename: Laurentius A C J
authors.initials: LA
authors.lastname: Voesenek
authors.affiliation: Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3584CH Utrecht, The Netherlands (D.D., K.R.S.O., L.A.C.J.V., R.P., R.S.); and Department of Biological Sciences, University of Alberta, Alberta, Canada T6J2E9 (K.R.S.O.) r.pierik@uu.nl r.sasidharan@uu.nl.
authors.forename: Ronald
authors.identifier: 0000-0002-5320-6817
authors.initials: R
authors.lastname: Pierik
authors.affiliation: Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3584CH Utrecht, The Netherlands (D.D., K.R.S.O., L.A.C.J.V., R.P., R.S.); and Department of Biological Sciences, University of Alberta, Alberta, Canada T6J2E9 (K.R.S.O.) r.pierik@uu.nl r.sasidharan@uu.nl.
authors.forename: Rashmi
authors.identifier: 0000-0002-6940-0657
authors.initials: R
authors.lastname: Sasidharan
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development; D016000:Cluster Analysis; D005030:Ethylenes / Q000494:pharmacology*; D020869:Gene Expression Profiling / Q000379:methods*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects* / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects* / Q000528:radiation effects; D063990:Gene Ontology; D018546:Hypocotyl / Q000235:genetics* / Q000254:growth & development; D008027:Light; D010788:Photosynthesis / Q000235:genetics; D010937:Plant Growth Regulators / Q000494:pharmacology; D036226:Seedlings / Q000235:genetics / Q000254:growth & development
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; C036216:ethylene