title: Regulation of seedling growth by ethylene and the ethylene-auxin crosstalk.
abstract: This review highlights that the auxin gradient, established by local auxin biosynthesis and transport, can be controlled by ethylene, and steers seedling growth. A better understanding of the mechanisms in Arabidopsis will increase potential applications in crop species. In dark-grown Arabidopsis seedlings, exogenous ethylene treatment triggers an exaggeration of the apical hook, the inhibition of both hypocotyl and root elongation, and radial swelling of the hypocotyl. These features are predominantly based on the differential cell elongation in different cells/tissues mediated by an auxin gradient. Interestingly, the physiological responses regulated by ethylene and auxin crosstalk can be either additive or synergistic, as in primary root and root hair elongation, or antagonistic, as in hypocotyl elongation. This review focuses on the crosstalk of these two hormones at the seedling stage. Before illustrating the crosstalk, ethylene and auxin biosynthesis, metabolism, transport and signaling are briefly discussed.
authors.affiliation: Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium.
authors.forename: Yuming
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: Vandenbussche
authors.affiliation: Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium. dominique.vanderstraeten@ugent.be.
authors.forename: Dominique
authors.identifier: http://orcid.org/0000-0002-7755-1420
authors.initials: D
authors.lastname: Van Der Straeten
mesh_terms: D001692:Biological Transport; D005030:Ethylenes / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D036226:Seedlings / Q000254:growth & development* / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D005030:Ethylenes; D007210:Indoleacetic Acids; C036216:ethylene
keywords: Apical hook; Auxin gradient; Ethylene; Hypocotyl; Phytohormones; Root