title: A mechanically sensitive cell layer regulates the physical properties of the Arabidopsis seed coat.
abstract: Endogenous mechanical stresses regulate plant growth and development. Tensile stress in epidermal cells affects microtubule reorientation and anisotropic cell wall deposition, and mechanical stimulus at the meristem regulates trafficking and polar localization of auxin transporters. However, the mechanical regulation of other plant growth regulators has not been demonstrated. Here we propose that during seed growth, mechanical stress exerted by the expanding embryo and endosperm is perceived by a specific mechanosensitive cell layer in the seed coat. We show that the adaxial epidermis of the outer integument thickens its cell wall in a mechanosensitive fashion, demonstrates microtubule dynamics consistent with mechanical stress perception and shows mechanosensitive expression of ELA1, a regulator of seed size and gibberellic acid (GA) metabolism. By exploiting physical and genetic compartmentalization, and combining genetic and surgical techniques, we propose a mechanistic link between mechanical stress and GA accumulation that regulates seed development.
authors.affiliation: Laboratoire Reproduction et Développement des Plantes (RDP), ENS de Lyon/CNRS UMR 5667/INRA UMR 879 /UCBL, 46 Allée d'Italie, 69364 Lyon, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Creff
authors.affiliation: 1] University Bordeaux, Bordeaux Imaging Center, UMS 3420, F-33000 Bordeaux, France [2] CNRS, Bordeaux Imaging Center, UMS 3420, F-33000 Bordeaux, France.
authors.forename: Lysiane
authors.initials: L
authors.lastname: Brocard
authors.affiliation: Laboratoire Reproduction et Développement des Plantes (RDP), ENS de Lyon/CNRS UMR 5667/INRA UMR 879 /UCBL, 46 Allée d'Italie, 69364 Lyon, France.
authors.forename: Gwyneth
authors.initials: G
authors.lastname: Ingram
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002473:Cell Wall / Q000502:physiology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005875:Gibberellins / Q000378:metabolism; D040542:Mechanotransduction, Cellular; D008870:Microtubules / Q000502:physiology*; D012639:Seeds / Q000166:cytology / Q000254:growth & development*
chemical_list: D029681:Arabidopsis Proteins; D005875:Gibberellins; D003577:Cytochrome P-450 Enzyme System; C007842:gibberellic acid; C000591697:cytochrome P-450 714A1 protein, Arabidopsis