Alignment of Cortical Microtubules by Anisotropic Wall Stresses

1990 ◽  
Vol 17 (6) ◽  
pp. 601 ◽  
Author(s):  
RE Williamson
Keyword(s):  
Cell Shape ◽  
Feedback Loop ◽  
Plant Cells ◽  
Cellulose Microfibrils ◽  
Specific Information ◽  
Mechanical Forces ◽  
Cortical Microtubules ◽  
Directional Information ◽  
Cell Position ◽  
Single Protein

Anisotropic mechanical forces exist in the walls of all turgid plant cells except those of spherical unicells. These forces potentially offer the cell important directional information regarding its major and minor axes, and the more complicated force patterns expected in multicellular organs could offer location-specific information. A mechanism is proposed to measure directional forces in the wall as deformations (strain) of molecules associated with cellulose microfibrils and transmit the information across the plasma membrane to orient cortical microtubules. Because microtubules in turn orient the synthesis of the cellulose microfibrils that determine the direction of future cell expansion, a feedback loop is established relating future cell shape to present cell shape and cell position. The loop can provide positive feedback to magnify a small asymmetry in shape, to reinforce an existing growth axis in a cylindrical cell or, by modification of the proteins postulated to convey directional information between wall and cytoplasm, the loop can be broken and the same directional information used to establish a new orientation for cortical microtubules. In this way, modification of a single protein replaces a transverse microtubule array with a helical one.

scholarly journals Mechanical properties of the stigmatic cell wall mediate pollen tube path in Arabidopsis

2018 ◽  
Author(s):  
Lucie Riglet ◽  
Frédérique Rozier ◽  
Chie Kodera ◽  
Isabelle Fobis-Loisy ◽  
Thierry Gaude
Keyword(s):  
Cell Wall ◽  
Pollen Tube ◽  
Cell Shape ◽  
Cell Imaging ◽  
Pollen Tubes ◽  
Mechanical Anisotropy ◽  
Cellulose Microfibrils ◽  
Mechanical Forces ◽  
Cortical Microtubules ◽  
Isotropic Reorientation

ABSTRACTSuccessful fertilization in angiosperms depends on the proper trajectory of pollen tubes through the pistil tissues to reach the ovules. Pollen tubes first grow within the cell wall of the papilla cells, applying pressure to the cell. Mechanical forces are known to play a major role in plant cell shape by controlling the orientation of cortical microtubules (CMTs), which in turn mediate deposition of cellulose microfibrils (CMFs). Here, by combining cell imaging and genetic approaches, we show that isotropic reorientation of CMTs and CMFs in aged and katanin1-5 (ktn1-5) papilla cells is accompanied by a tendency of pollen tubes to coil around the papillae. Furthermore, we uncover that aged and ktn1-5 papilla cells have a softer cell wall and provide less resistance to pollen tube growth. Our results reveal an unexpected role for KTN1 in pollen tube guidance by ensuring mechanical anisotropy of the papilla cell wall.

Regulation by Gibberellins of the Orientation of Cortical Microtubules in Plant Cells

1993 ◽  
Vol 20 (5) ◽  
pp. 461 ◽  
Author(s):  
H Shibaoka
Keyword(s):  
Plasma Membrane ◽  
Cell Expansion ◽  
Plant Cells ◽  
Cellulose Microfibrils ◽  
Molecular Architecture ◽  
Cortical Microtubules ◽  
Microtubule Stability ◽  
The Stability ◽  
The Way

Gibberellins control the direction of expansion of plant cells. They change the orientation of cellulose microfibrils by changing the orientation of cortical microtubules and, hence, the direction of cell expansion. When gibberellins change the orientation of cortical microtubules, they also change their stability. If the way in which gibberellins change the orientation of microtubules is identical to the way in which they change microtubule stability, then studies on the mechanism that regulates this stability should give us some clues to the mechanism that regulates the orientation of microtubules. With this possibility in mind, we undertook a series of studies on the stability of cortical microtubules. These revealed that the association of cortical microtubules with the plasma membrane is an important part of the mechanism for their stabilisation. Gibberellins seem to change the stability of microtubules by affecting their association with the plasma membrane. To study the way in which the gibberellins affect this association, it is necessary to clarify the molecular architecture of the structure that links cortical microtubules with the plasma membrane.

scholarly journals KATANIN-dependent mechanical properties of the stigmatic cell wall mediate the pollen tube path in Arabidopsis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Lucie Riglet ◽  
Frédérique Rozier ◽  
Chie Kodera ◽  
Simone Bovio ◽  
Julien Sechet ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Pollen Tube ◽  
Cell Walls ◽  
Cell Shape ◽  
Pollen Tubes ◽  
Mechanical Anisotropy ◽  
Cellulose Microfibrils ◽  
Cortical Microtubules ◽  
Isotropic Reorientation

Successful fertilization in angiosperms depends on the proper trajectory of pollen tubes through the pistil tissues to reach the ovules. Pollen tubes first grow within the cell wall of the papilla cells, applying pressure to the cell. Mechanical forces are known to play a major role in plant cell shape by controlling the orientation of cortical microtubules (CMTs), which in turn mediate deposition of cellulose microfibrils (CMFs). Here, by combining imaging, genetic and chemical approaches, we show that isotropic reorientation of CMTs and CMFs in aged Col-0 and katanin1-5 (ktn1-5) papilla cells is accompanied by a tendency of pollen tubes to coil around the papillae. We show that this coiled phenotype is associated with specific mechanical properties of the cell walls that provide less resistance to pollen tube growth. Our results reveal an unexpected role for KTN1 in pollen tube guidance on the stigma by ensuring mechanical anisotropy of the papilla cell wall.

scholarly journals Mechanical feedback-loop regulation of morphogenesis in plants

Development ◽  
2020 ◽  
Vol 147 (16) ◽  
pp. dev177964
Author(s):  
Arun Sampathkumar
Keyword(s):  
Cell Wall ◽  
Environmental Conditions ◽  
Feedback Loop ◽  
Biological Process ◽  
Plant Cells ◽  
Mechanical Forces ◽  
Robust Sensing ◽  
Sessile Organisms ◽  
Mechanical Feedback

ABSTRACTMorphogenesis is a highly controlled biological process that is crucial for organisms to develop cells and organs of a particular shape. Plants have the remarkable ability to adapt to changing environmental conditions, despite being sessile organisms with their cells affixed to each other by their cell wall. It is therefore evident that morphogenesis in plants requires the existence of robust sensing machineries at different scales. In this Review, I provide an overview on how mechanical forces are generated, sensed and transduced in plant cells. I then focus on how such forces regulate growth and form of plant cells and tissues.

scholarly journals The Structure and Plastic Properties of the Cell Wall of Nitella in Relation to Extension Growth

1966 ◽  
Vol 19 (3) ◽  
pp. 439 ◽  
Author(s):  
MC Probine ◽  
NF Barber
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Cell Growth ◽  
Elastic Properties ◽  
Cell Shape ◽  
Cellulose Microfibrils ◽  
Theoretical Treatment ◽  
Plastic Properties ◽  
Growing Cell ◽  
Plastic Matrix

The internodal cells of Nitella opaca L. have been used in earlier studies to assess the part which mechanical properties of the wall may play in the control of cell growth (Probine and Preston 1962). The wall is mechanically anisotropic in both its plastic and elastic properties, and it is shown in this paper by an approximate theoretical treatment that a mat of cellulose microfibrils, embedded in a plastic matrix and having a distribution in the plane of the wall like that observed in Nitella, would lead to longitUdinal and transverse plastic extensions in the ratio observed in the growing cell. Factors which would affect cell shape are discussed.

Organization of cortical microtubules in plant cells

1995 ◽  
Vol 7 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Richard J. Cyr ◽  
Barry A. Palevitz
Keyword(s):  
Plant Cells ◽  
Cortical Microtubules

scholarly journals Passive Mechanical Forces Control Cell-Shape Change during Drosophila Ventral Furrow Formation

2014 ◽  
Vol 107 (4) ◽  
pp. 998-1010 ◽  
Author(s):  
Oleg Polyakov ◽  
Bing He ◽  
Michael Swan ◽  
Joshua W. Shaevitz ◽  
Matthias Kaschube ◽  
...  
Keyword(s):  
Cell Shape ◽  
Shape Change ◽  
Control Cell ◽  
Mechanical Forces ◽  
Cell Shape Change ◽  
Ventral Furrow

Cell Shape Dictates Differential Sensitivity of Subcellular Contractile Forces in Response to Directional Substrate Stretch

2013 ◽  
Author(s):  
Yue Shao ◽  
Jennifer M. Mann ◽  
Jianping Fu
Keyword(s):  
Cell Shape ◽  
Feedback Loop ◽  
Focal Adhesions ◽  
Differential Sensitivity ◽  
Matrix Rigidity ◽  
Cell Geometry ◽  
Cellular Mechanotransduction ◽  
Cellular Behaviors ◽  
External Forces ◽  
Contractile Forces

In past decades, it has been well demonstrated that cellular contractile forces against the extracellular matrix (ECM) plays an important role in regulating cellular behaviors such as spreading, adhesion and differentiation [1]. Recent studies have found that focal adhesions (FAs) and subcellular contractile forces mediated by FAs have an intimate connection and form an important feedback loop to control cellular mechanotransduction in response to mechanical cues such as matrix rigidity, cell geometry and external forces [2]. Therefore, understanding how FA-mediated contractile forces are regulated by those factors is critical for our understanding of cellular mechanotransduction and mechano-responsiveness.

Mitotic Disrupter Herbicides

Weed Science ◽  
1991 ◽  
Vol 39 (3) ◽  
pp. 450-457 ◽  
Author(s):  
Kevin C. Vaughn ◽  
Larry P. Lehnen
Keyword(s):  
Cell Walls ◽  
Cell Shape ◽  
Cortical Microtubules ◽  
Root Tips ◽  
Dramatic Effect ◽  
Nuclear Membranes ◽  
Microtubule Polymerization ◽  
Primary Mechanism ◽  
Spindle Microtubules ◽  
Kinetochore Region

Approximately one-quarter of all herbicides that have been marketed affect mitosis as a primary mechanism of action. All of these herbicides appear to interact directly or indirectly with the microtubule. Dinitroaniline and phosphoric amide herbicides inhibit microtubule polymerization from free tubulin subunits. Because of the loss of spindle and kinetochore microtubules, chromosomes cannot move to the poles during mitosis, resulting in cells exhibiting an arrested prometaphase configuration. Nuclear membranes re-form around the chromosomal masses to form lobed nuclei. Cortical microtubules, which influence cell shape, are also absent, and, as a result, the cell expands isodiametrically. In root tips and other structures that are normally elongated, these herbicides induce a characteristic club-shaped swelling. Pronamide and MON 7200 induce similar effects, except that tufts of microtubules remain at the kinetochore region of the chromosomes. The carbamate herbicides barban, propham, and chlorpropham alter the organization of the spindle microtubules so that multiple spindles are formed. Chromosomes move to many poles and multiple nuclei result. Abnormal branched cell walls partly separate the nuclei. Terbutol induces “star anaphase” chromosome configurations in which the chromosomes are drawn into an area at the poles in a star-like aggregation. DCPA's most dramatic effect is on phragmoplast microtubule arrays. Multiple, branched, and curved phragmoplasts are found after herbicide treatment. These disrupters should prove to be useful tools in investigations of the proteins and structures required for a successful cell division.

scholarly journals Cytoskeletal organization in isolated plant cells under geometry control

2020 ◽  
Vol 117 (29) ◽  
pp. 17399-17408 ◽  
Author(s):  
Pauline Durand-Smet ◽  
Tamsin A. Spelman ◽  
Elliot M. Meyerowitz ◽  
Henrik Jönsson
Keyword(s):  
Cell Shape ◽  
Flexural Rigidity ◽  
Persistence Length ◽  
Plant Cells ◽  
Cytoskeletal Proteins ◽  
Three Dimensions ◽  
Animal Cells ◽  
Living Plant ◽  
Cytoskeletal Organization ◽  
Actin Organization

The cytoskeleton plays a key role in establishing robust cell shape. In animals, it is well established that cell shape can also influence cytoskeletal organization. Cytoskeletal proteins are well conserved between animal and plant kingdoms; nevertheless, because plant cells exhibit major structural differences to animal cells, the question arises whether the plant cytoskeleton also responds to geometrical cues. Recent numerical simulations predicted that a geometry-based rule is sufficient to explain the microtubule (MT) organization observed in cells. Due to their high flexural rigidity and persistence length of the order of a few millimeters, MTs are rigid over cellular dimensions and are thus expected to align along their long axis if constrained in specific geometries. This hypothesis remains to be testedin cellulo. Here, we explore the relative contribution of geometry to the final organization of actin and MT cytoskeletons in single plant cells ofArabidopsis thaliana. We show that the cytoskeleton aligns with the long axis of the cells. We find that actin organization relies on MTs but not the opposite. We develop a model of self-organizing MTs in three dimensions, which predicts the importance of MT severing, which we confirm experimentally. This work is a first step toward assessing quantitatively how cellular geometry contributes to the control of cytoskeletal organization in living plant cells.

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