Subcellular and supracellular mechanical stress prescribes cytoskeleton behavior in Arabidopsis cotyledon pavement cells
- California Institute of Technology, United States
- University of Cambridge, United Kingdom
- Lund University, Sweden
- INRA-CNRS-UCBL-ENS Lyon, France
- Bruker Nano GmbH, Germany
- Howard Hughes Medical Institute, California Institute of Technology, United States
Figures
Figure 1 with 3 supplements
Mechanical heterogeneity of pavement cells correlates with microtubule patterns.
(A) Microtubule bundling persits in indenting regions of pavement cells over time. Scale bars 20 μm. (B) Microtubule anisotropy over time, lines represent average orientation of microtubule arrays …
Figure 1—figure supplement 1
Microtubule organization and mechanical heterogeneity.
Additional examples of microtubule bundling persisting along the indenting regions of pavement cells over time, far right panels shows lines representing the average orientation of microtubule …
Figure 1—figure supplement 2
Microtubule organization and mechanical heterogeneity.
Additional example of stiffness map of the outer walls in another cotyledon obtained with AFM.
Figure 1—figure supplement 3
Microtubule organization and mechanical heterogeneity.
(A and B) Microtubule orientation on the outer (A) and inner (B) side of epidermal pavement cells Scale bar 25 μm.
Figure 2 with 3 supplements
Microtubule patterns correlate with physical stress patterns.
(A) Mesh showing stress directions, with the corresponding microtubule organization shown in panel B. Highlighted cells in green are represented in panels C–E and Figure 2—figure supplement 1A–C. (C)…
Figure 2—figure supplement 1
Microtubule organization and correlation with stress patterns.
(A–C) Example cell from Figure 2A showing correlation between predicted physical stresses and microtubule organization. Scale bars 20 μm.
Figure 2—figure supplement 2
Simulation of single pressurized pavement cell shape A and D.
3D cell with epidermal, bottom, and anticlinal wall. (B and E) The bottom wall removed and replaced with boundary conditions at the bottom of the anticlinal wall. (C and F) Surface model of …
Figure 2—figure supplement 3
Microtubule organization and correlation with stress patterns.
Color map of the cosine of angle between first principal stress without (white lines) and with anisotropic material and feedback to stress direction (black lines).
Figure 3 with 4 supplements
Extrinsic perturbation of mechanical forces induce directional changes in microtubule arrays.
(A and B) Mechanical models showing changes in stress directions upon ablation. (C) Large scale ablation of cotyledons result in circumferential distribution of microtubule arrays around the site of …
Figure 3—figure supplement 1
Mechanical compression leads to increased microtubule anisotropy in pavement cells.
(A and B) Mechanical models predict an increase in mechanical stress compression. (C and D) Depth color-coded Z-stack of microtubules, immediately after applying compressive forces (C) and after 7 …
Figure 3—figure supplement 2
Compression of pavement cells results in stabilization of microtubule array orientation.
Note the increased MT anisotropy during compression and reduced MT anisotropy upon release of compression.Scale bars 25 μm.
Figure 3—figure supplement 3
Cotyledon epidermis is under tension.
(A) Time series images of a cut cotyledon. Scale bar 500 μm. (B) Kymograph along the dashed red line in panel (A) showing gap opening immediately after physical laceration of the cotyledon, and …
Figure 3—figure supplement 4
Microtubule response to changes in physical forces in katanin mutant.
Depth color-coded Z stack of microtubule arrays before (A) and 8 hr after compression in botero 1-7 (B). Scale bar 50 μm. (C) Transect along dashed line in (B) showing flattening of cell due to …
Figure 4 with 2 supplements
Stress intensity regulates microtubule alignment.
(A and B) Simulation showing less pronounced circumferential rearrangements of stresses after ablation of single cell. Images of microtubule reporter line before (C) and 7 hr after (D) ablation of …
Figure 4—figure supplement 1
Microtubule array organization in guard cells remains unaffected by changes in directional force field.
Close up image of microtubule arrays in guard cell before (A) and 7 hr after (B) large-scale ablation. Majority of the guard cells retain the transverse pattern of microtubule arrays after …
Figure 4—figure supplement 2
Microtubule response to isoxaben treatment.
Changes in microtubule arrays before (A) and after treatment with 40 μM isoxaben for 16 hr (B). (C) Histogram showing increase in nematic tensor values after isoxaben treatment. Error bars represent …
Figure 5
Mechanical perturbations increase bundling by promoting severing.
3D surface plot of YFP microtubule time series images representing a typical microtubule severing event (A), arrowheads indicate microtubule-severing at a crossover sites. Scale bar 5 μm. (B) …
Figure 6
Mechanical forces regulate pavement cell shape by controlling microtubule organization and cellulose deposition.
https://doi.org/10.7554/eLife.01967.025
Author response image 1
Simulation of pressurized doubly curved, saddle-like shape.
The color map shows the value of the second principal stress. Blue-low, red-high, black-values below zero. The region in the valley close to the boundary is under compression, which transforms to …
Author response image 2
Simulation of single pressurized pavement cell shape.
A and D. 3D cell with epidermal, bottom and anticlinal wall. B and E. The cell model with bottom wall removed and replaced with boundary conditions at the bottom of anticlinal walls. C and F surface …
Author response image 3
Simulation of ablation with 3D anticlinal walls included. The color map shows the value of first (A, C) and second (B, D) principal stresses (blue-low, red-high) before (A, B) and after (C, D) …
Author response image 4
Close up of a merged image of cell boundary movement before (white) and after (red) ablation.
Scale bar 1 micrometer.
Author response image 5
Simulation showing less pronounced circumferential rearrangements of stresses (white lines indicate maximal tensile stress directions) after ablation of a single cell (grey cell). (A) Before …
Author response image 6
Images of microtubule reporter line before (A) and 7h after (B) ablation of single cell, showing aligned microtubule arrays not completely circumferential after ablation of single cell. Scale bars …
Author response image 7
Close up image of microtubule arrays in guard cell before and after large-scale ablation.
Majority of the guard cells retain the transverse pattern of microtubule arrays after laceration.
Author response image 8
Color map shows total displacement (including z coordinate) in a single pressurized 3D pavement cell model.
The left edges of the cell were fixed, simulating attachment to unaltered tissue. The right side of the cell is next to ablated region. The tips of the lobes in ablation neighborhood show low values …
Videos
Video 1
Depth color-coded time series images showing changes in microtubule organization following compression.
Scale bar 20 µm.
Video 2
Laceration of cotyledon shows outward displacement of cut edges.
Scale bar 500 µm.
Video 3
Video of computational simulation showing circumferential distribution of stress and increase in MT anisotropy after ablation.
https://doi.org/10.7554/eLife.01967.018
Video 4
Depth color-coded time series images showing microtubule arrays in botero 1-7 does not induce hyper-alignment of microtubule arrays after compression.
Scale bar 50 µm.
Video 5
Video showing severing of microtubule immediately after and 4 hr post ablation of cells. Red dots mark sites of microtubule severing.
Scale bar 25 µm.
Additional files
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Supplementary file 1
Additional information about computational models.
- https://doi.org/10.7554/eLife.01967.026
