TY - JOUR A1 - Majda, Mateusz A1 - Grones, Peter A1 - Sintorn, Ida-Maria A1 - Vain, Thomas A1 - Milani, Pascale A1 - Krupinski, Pawel A1 - Zagorska-Marek, Beata A1 - Viotti, Corrado A1 - Jonsson, Henrik A1 - Mellerowicz, Ewa J. A1 - Hamant, Olivier A1 - Robert, Stephanie T1 - Mechanochemical Polarization of Contiguous Cell Walls Shapes Plant Pavement Cells JF - Developmental cell N2 - The epidermis of aerial plant organs is thought to be limiting for growth, because it acts as a continuous load-bearing layer, resisting tension. Leaf epidermis contains jigsaw puzzle piece-shaped pavement cells whose shape has been proposed to be a result of subcellular variations in expansion rate that induce local buckling events. Paradoxically, such local compressive buckling should not occur given the tensile stresses across the epidermis. Using computational modeling, we show that the simplest scenario to explain pavement cell shapes within an epidermis under tension must involve mechanical wall heterogeneities across and along the anticlinal pavement cell walls between adjacent cells. Combining genetics, atomic force microscopy, and immunolabeling, we demonstrate that contiguous cell walls indeed exhibit hybrid mechanochemical properties. Such biochemical wall heterogeneities precede wall bending. Altogether, this provides a possible mechanism for the generation of complex plant cell shapes. Y1 - 2017 U6 - https://doi.org/10.1016/j.devcel.2017.10.017 SN - 1534-5807 SN - 1878-1551 VL - 43 SP - 290 EP - + PB - Cell Press CY - Cambridge ER - TY - GEN A1 - Krupinski, Pawel A1 - Bozorg, Behruz A1 - Larsson, André A1 - Pietra, Stefano A1 - Grebe, Markus A1 - Jönsson, Henrik T1 - A model analysis of mechanisms for radial microtubular patterns at root hair initiation sites T2 - Frontiers in plant science N2 - Plant cells have two main modes of growth generating anisotropic structures. Diffuse growth where whole cell walls extend in specific directions, guided by anisotropically positioned cellulose fibers, and tip growth, with inhomogeneous addition of new cell wall material at the tip of the structure. Cells are known to regulate these processes via molecular signals and the cytoskeleton. Mechanical stress has been proposed to provide an input to the positioning of the cellulose fibers via cortical microtubules in diffuse growth. In particular, a stress feedback model predicts a circumferential pattern of fibers surrounding apical tissues and growing primordia, guided by the anisotropic curvature in such tissues. In contrast, during the initiation of tip growing root hairs, a star-like radial pattern has recently been observed. Here, we use detailed finite element models to analyze how a change in mechanical properties at the root hair initiation site can lead to star-like stress patterns in order to understand whether a stress-based feedback model can also explain the microtubule patterns seen during root hair initiation. We show that two independent mechanisms, individually or combined, can be sufficient to generate radial patterns. In the first, new material is added locally at the position of the root hair. In the second, increased tension in the initiation area provides a mechanism. Finally, we describe how a molecular model of Rho-of-plant (ROP) GTPases activation driven by auxin can position a patch of activated ROP protein basally along a 2D root epidermal cell plasma membrane, paving the way for models where mechanical and molecular mechanisms cooperate in the initial placement and outgrowth of root hairs. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 435 KW - plant cell wall KW - finite element modeling KW - computational morphodynamics KW - root hair initiation KW - microtubules KW - cellulose fibers KW - composite material Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-407181 ER - TY - JOUR A1 - Krupinski, Pawel A1 - Bozorg, Behruz A1 - Larsson, Andre A1 - Pietra, Stefano A1 - Grebe, Markus A1 - Jönsson, Henrik T1 - A Model Analysis of Mechanisms for Radial Microtubular Patterns at Root Hair Initiation Sites JF - Frontiers in plant science N2 - Plant cells have two main modes of growth generating anisotropic structures. Diffuse growth where whole cell walls extend in specific directions, guided by anisotropically positioned cellulose fibers, and tip growth, with inhomogeneous addition of new cell wall material at the tip of the structure. Cells are known to regulate these processes via molecular signals and the cytoskeleton. Mechanical stress has been proposed to provide an input to the positioning of the cellulose fibers via cortical microtubules in diffuse growth. In particular, a stress feedback model predicts a circumferential pattern of fibers surrounding apical tissues and growing primordia, guided by the anisotropic curvature in such tissues. In contrast, during the initiation of tip growing root hairs, a star-like radial pattern has recently been observed. Here, we use detailed finite element models to analyze how a change in mechanical properties at the root hair initiation site can lead to star-like stress patterns in order to understand whether a stress-based feedback model can also explain the microtubule patterns seen during root hair initiation. We show that two independent mechanisms, individually or combined, can be sufficient to generate radial patterns. In the first, new material is added locally at the position of the root hair. In the second, increased tension in the initiation area provides a mechanism. Finally, we describe how a molecular model of Rho-of-plant (ROP) GTPases activation driven by auxin can position a patch of activated ROP protein basally along a 2D root epidermal cell plasma membrane, paving the way for models where mechanical and molecular mechanisms cooperate in the initial placement and outgrowth of root hairs. KW - plant cell wall KW - finite element modeling KW - computational morphodynamics KW - root hair initiation KW - microtubules KW - cellulose fibers KW - composite material Y1 - 2016 U6 - https://doi.org/10.3389/fpls.2016.01560 SN - 1664-462X VL - 7 PB - Frontiers Research Foundation CY - Lausanne ER -