@article{jewaria_reduced_2025,
	title = {Reduced {RG}-{II} pectin dimerization disrupts differential growth by attenuating hormonal regulation},
	volume = {11},
	url = {https://www.science.org/doi/10.1126/sciadv.ads0760},
	doi = {10.1126/sciadv.ads0760},
	abstract = {Defects in cell wall integrity (CWI) profoundly affect plant growth, although, underlying mechanisms are not well understood. We show that in Arabidopsis mur1 mutant, CWI defects from compromising dimerization of RG-II pectin, a key component of cell wall, attenuate the expression of auxin response factors ARF7-ARF19. As a result, polar auxin transport components are misexpressed, disrupting auxin response asymmetry, leading to defective apical hook development. Accordingly, mur1 hook defects are suppressed by enhancing ARF7 expression. In addition, expression of brassinosteroid biosynthesis genes is down-regulated in mur1 mutant, and supplementing brassinosteroid or enhancing brassinosteroid signaling suppresses mur1 hook defects. Intriguingly, brassinosteroid enhances RG-II dimerization, showing hormonal feedback to the cell wall. Our results thus reveal a previously unrecognized link between cell wall defects from reduced RG-II dimerization and growth regulation mediated via modulation of auxin-brassinosteroid pathways in early seedling development.},
	number = {7},
	urldate = {2025-02-20},
	journal = {Science Advances},
	publisher = {American Association for the Advancement of Science},
	author = {Jewaria, Pawan Kumar and Aryal, Bibek and Begum, Rifat Ara and Wang, Yaowei and Sancho-Andrés, Gloria and Baba, Abu Imran and Yu, Meng and Li, Xiaojuan and Lin, Jinxing and Fry, Stephen C. and Verger, Stephane and Russinova, Eugenia and Jonsson, Kristoffer and Bhalerao, Rishikesh P.},
	month = feb,
	year = {2025},
	pages = {eads0760},
}

Defects in cell wall integrity (CWI) profoundly affect plant growth, although, underlying mechanisms are not well understood. We show that in Arabidopsis mur1 mutant, CWI defects from compromising dimerization of RG-II pectin, a key component of cell wall, attenuate the expression of auxin response factors ARF7-ARF19. As a result, polar auxin transport components are misexpressed, disrupting auxin response asymmetry, leading to defective apical hook development. Accordingly, mur1 hook defects are suppressed by enhancing ARF7 expression. In addition, expression of brassinosteroid biosynthesis genes is down-regulated in mur1 mutant, and supplementing brassinosteroid or enhancing brassinosteroid signaling suppresses mur1 hook defects. Intriguingly, brassinosteroid enhances RG-II dimerization, showing hormonal feedback to the cell wall. Our results thus reveal a previously unrecognized link between cell wall defects from reduced RG-II dimerization and growth regulation mediated via modulation of auxin-brassinosteroid pathways in early seedling development.

@article{bogdziewiez_q-warg_2025,
	title = {The {Q}-{Warg} {Pipeline}: {A} {Robust} and {Versatile} {Workflow} for {Quantitative} {Analysis} of {Protoplast} {Culture} {Conditions}},
	volume = {9},
	copyright = {© 2025 The Author(s). Plant Direct published by American Society of Plant Biologists and the Society for Experimental Biology and John Wiley \& Sons Ltd.},
	issn = {2475-4455},
	shorttitle = {The {Q}-{Warg} {Pipeline}},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pld3.70090},
	doi = {10.1002/pld3.70090},
	abstract = {Single cells offer a simplified model for investigating complex mechanisms such as cell–cell adhesion. Protoplasts, plant cells without cell walls (CWs), have been instrumental in plant research, industrial applications, and breeding. However, because of the absence of a CW, protoplasts are not considered “true” plant cells, making them less relevant for biophysical studies. Current protocols for CW recovery in protoplasts vary widely among laboratories and starting materials, requiring lab-specific optimizations that often depend on expert knowledge and qualitative assessments. To address this, we have developed a user-friendly streamlined workflow, the Q-Warg pipeline, which enables quantitative comparison of various conditions for CW recovery post-protoplasting. This pipeline employs fluorescence imaging and tailored processing to measure parameters such as morphometry, cell viability, and CW staining intensity. Using this approach, we optimized culture conditions to obtain single plant cells (SPCs) with recovered CWs. Additionally, we demonstrated the robustness and versatility of the workflow by quantifying different fluorescent signals in protoplast suspensions. Overall, the Q-Warg pipeline provides a widely accessible and user-friendly solution for robust and unbiased characterization of protoplasts culture. The quantitative data generated by the pipeline will be useful in the future to decipher the mechanisms regulating protoplast viability and regeneration.},
	language = {en},
	number = {7},
	urldate = {2025-07-25},
	journal = {Plant Direct},
	author = {Bogdziewiez, Léa and Froeling, Rik and Schöppl, Patricia and Juquel, Jeanne and Antoniadi, Ioanna and Skalický, Vladimìr and Mathey, Ambroise and Fattaccioli, Jacques and Sprakel, Joris and Verger, Stéphane},
	year = {2025},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/pld3.70090},
	keywords = {Arabidopsis thaliana, cell wall, fluorescence, protoplasts, quantification, recovery, regeneration, viability},
	pages = {e70090},
}

Single cells offer a simplified model for investigating complex mechanisms such as cell–cell adhesion. Protoplasts, plant cells without cell walls (CWs), have been instrumental in plant research, industrial applications, and breeding. However, because of the absence of a CW, protoplasts are not considered “true” plant cells, making them less relevant for biophysical studies. Current protocols for CW recovery in protoplasts vary widely among laboratories and starting materials, requiring lab-specific optimizations that often depend on expert knowledge and qualitative assessments. To address this, we have developed a user-friendly streamlined workflow, the Q-Warg pipeline, which enables quantitative comparison of various conditions for CW recovery post-protoplasting. This pipeline employs fluorescence imaging and tailored processing to measure parameters such as morphometry, cell viability, and CW staining intensity. Using this approach, we optimized culture conditions to obtain single plant cells (SPCs) with recovered CWs. Additionally, we demonstrated the robustness and versatility of the workflow by quantifying different fluorescent signals in protoplast suspensions. Overall, the Q-Warg pipeline provides a widely accessible and user-friendly solution for robust and unbiased characterization of protoplasts culture. The quantitative data generated by the pipeline will be useful in the future to decipher the mechanisms regulating protoplast viability and regeneration.

@article{baba_cell_2024,
	title = {Cell adhesion maintenance and controlled separation in plants},
	volume = {2},
	issn = {2813-821X},
	url = {https://www.frontiersin.org/journals/plant-physiology/articles/10.3389/fphgy.2024.1369575/full},
	doi = {10.3389/fphgy.2024.1369575},
	abstract = {{\textless}p{\textgreater}Cell-cell adhesion is a fundamental aspect of maintaining multicellular integrity while ensuring controlled cell and organ shedding, intercellular space formation and intrusive growth. Understanding of the precise mechanisms governing regulated cell separation, such as abscission, considerably progressed in recent decades. However, our comprehension of how plants maintain adhesion within tissues in which it is essential remains limited. Here we review some of the well-established knowledge along with latest discoveries that lead us to rethink the way developmentally controlled cell separation and adhesion maintenance may work. We also specifically explore the relationship between growth and adhesion, highlighting their similarities and coupling, and propose a plausible framework in which growth and adhesion are tightly co-regulated.{\textless}/p{\textgreater}},
	language = {English},
	urldate = {2024-10-09},
	journal = {Frontiers in Plant Physiology},
	publisher = {Frontiers},
	author = {Baba, Abu Imran and Verger, Stéphane},
	month = feb,
	year = {2024},
	keywords = {Abscission, Adhesion, Cell Wall, Growth, SEPARATION},
}

\textlessp\textgreaterCell-cell adhesion is a fundamental aspect of maintaining multicellular integrity while ensuring controlled cell and organ shedding, intercellular space formation and intrusive growth. Understanding of the precise mechanisms governing regulated cell separation, such as abscission, considerably progressed in recent decades. However, our comprehension of how plants maintain adhesion within tissues in which it is essential remains limited. Here we review some of the well-established knowledge along with latest discoveries that lead us to rethink the way developmentally controlled cell separation and adhesion maintenance may work. We also specifically explore the relationship between growth and adhesion, highlighting their similarities and coupling, and propose a plausible framework in which growth and adhesion are tightly co-regulated.\textless/p\textgreater

@article{lorrai_cell_2024,
	title = {Cell wall integrity modulates {HOOKLESS1} and {PHYTOCHROME} {INTERACTING} {FACTOR4} expression controlling apical hook formation},
	volume = {196},
	issn = {0032-0889},
	url = {https://doi.org/10.1093/plphys/kiae370},
	doi = {10.1093/plphys/kiae370},
	abstract = {Formation of the apical hook in etiolated dicot seedlings results from differential growth in the hypocotyl apex and is tightly controlled by environmental cues and hormones, among which auxin and gibberellins (GAs) play an important role. Cell expansion is tightly regulated by the cell wall, but whether and how feedback from this structure contributes to hook development are still unclear. Here, we show that etiolated seedlings of the Arabidopsis (Arabidopsis thaliana) quasimodo2-1 (qua2) mutant, defective in pectin biosynthesis, display severe defects in apical hook formation and maintenance, accompanied by loss of asymmetric auxin maxima and differential cell expansion. Moreover, qua2 seedlings show reduced expression of HOOKLESS1 (HLS1) and PHYTOCHROME INTERACTING FACTOR4 (PIF4), which are positive regulators of hook formation. Treatment of wild-type seedlings with the cellulose inhibitor isoxaben (isx) also prevents hook development and represses HLS1 and PIF4 expression. Exogenous GAs, loss of DELLA proteins, or HLS1 overexpression partially restore hook development in qua2 and isx-treated seedlings. Interestingly, increased agar concentration in the medium restores, both in qua2 and isx-treated seedlings, hook formation, asymmetric auxin maxima, and PIF4 and HLS1 expression. Analyses of plants expressing a Förster resonance energy transfer-based GA sensor indicate that isx reduces accumulation of GAs in the apical hook region in a turgor-dependent manner. Lack of the cell wall integrity sensor THESEUS 1, which modulates turgor loss point, restores hook formation in qua2 and isx-treated seedlings. We propose that turgor-dependent signals link changes in cell wall integrity to the PIF4-HLS1 signaling module to control differential cell elongation during hook formation.},
	number = {2},
	urldate = {2024-10-04},
	journal = {Plant Physiology},
	author = {Lorrai, Riccardo and Erguvan, Özer and Raggi, Sara and Jonsson, Kristoffer and Široká, Jitka and Tarkowská, Danuše and Novák, Ondřej and Griffiths, Jayne and Jones, Alexander M and Verger, Stéphane and Robert, Stéphanie and Ferrari, Simone},
	month = oct,
	year = {2024},
	pages = {1562--1578},
}

Formation of the apical hook in etiolated dicot seedlings results from differential growth in the hypocotyl apex and is tightly controlled by environmental cues and hormones, among which auxin and gibberellins (GAs) play an important role. Cell expansion is tightly regulated by the cell wall, but whether and how feedback from this structure contributes to hook development are still unclear. Here, we show that etiolated seedlings of the Arabidopsis (Arabidopsis thaliana) quasimodo2-1 (qua2) mutant, defective in pectin biosynthesis, display severe defects in apical hook formation and maintenance, accompanied by loss of asymmetric auxin maxima and differential cell expansion. Moreover, qua2 seedlings show reduced expression of HOOKLESS1 (HLS1) and PHYTOCHROME INTERACTING FACTOR4 (PIF4), which are positive regulators of hook formation. Treatment of wild-type seedlings with the cellulose inhibitor isoxaben (isx) also prevents hook development and represses HLS1 and PIF4 expression. Exogenous GAs, loss of DELLA proteins, or HLS1 overexpression partially restore hook development in qua2 and isx-treated seedlings. Interestingly, increased agar concentration in the medium restores, both in qua2 and isx-treated seedlings, hook formation, asymmetric auxin maxima, and PIF4 and HLS1 expression. Analyses of plants expressing a Förster resonance energy transfer-based GA sensor indicate that isx reduces accumulation of GAs in the apical hook region in a turgor-dependent manner. Lack of the cell wall integrity sensor THESEUS 1, which modulates turgor loss point, restores hook formation in qua2 and isx-treated seedlings. We propose that turgor-dependent signals link changes in cell wall integrity to the PIF4-HLS1 signaling module to control differential cell elongation during hook formation.

@article{qamar_segmentation_2024,
	title = {Segmentation and characterization of macerated fibers and vessels using deep learning},
	volume = {20},
	issn = {1746-4811},
	url = {https://plantmethods.biomedcentral.com/articles/10.1186/s13007-024-01244-w},
	doi = {10.1186/s13007-024-01244-w},
	abstract = {Abstract
            
              Purpose
              Wood comprises different cell types, such as fibers, tracheids and vessels, defining its properties. Studying cells’ shape, size, and arrangement in microscopy images is crucial for understanding wood characteristics. Typically, this involves macerating (soaking) samples in a solution to separate cells, then spreading them on slides for imaging with a microscope that covers a wide area, capturing thousands of cells. However, these cells often cluster and overlap in images, making the segmentation difficult and time-consuming using standard image-processing methods.
            
            
              Results
              
                In this work, we developed an automatic deep learning segmentation approach that utilizes the one-stage YOLOv8 model for fast and accurate segmentation and characterization of macerated fiber and vessel form aspen trees in microscopy images. The model can analyze 32,640 x 25,920 pixels images and demonstrate effective cell detection and segmentation, achieving a
                
                  
                    \$\${\textbackslash}hbox \{mAP\}\_\{0.5-0.95\}\$\$
                    
                      
                        mAP
                        
                          0.5
                          -
                          0.95
                        
                      
                    
                  
                
                of 78 \%. To assess the model’s robustness, we examined fibers from a genetically modified tree line known for longer fibers. The outcomes were comparable to previous manual measurements. Additionally, we created a user-friendly web application for image analysis and provided the code for use on Google Colab.
              
            
            
              Conclusion
              By leveraging YOLOv8’s advances, this work provides a deep learning solution to enable efficient quantification and analysis of wood cells suitable for practical applications.},
	language = {en},
	number = {1},
	urldate = {2024-08-30},
	journal = {Plant Methods},
	author = {Qamar, Saqib and Baba, Abu Imran and Verger, Stéphane and Andersson, Magnus},
	month = aug,
	year = {2024},
	pages = {126},
}

Abstract Purpose Wood comprises different cell types, such as fibers, tracheids and vessels, defining its properties. Studying cells’ shape, size, and arrangement in microscopy images is crucial for understanding wood characteristics. Typically, this involves macerating (soaking) samples in a solution to separate cells, then spreading them on slides for imaging with a microscope that covers a wide area, capturing thousands of cells. However, these cells often cluster and overlap in images, making the segmentation difficult and time-consuming using standard image-processing methods. Results In this work, we developed an automatic deep learning segmentation approach that utilizes the one-stage YOLOv8 model for fast and accurate segmentation and characterization of macerated fiber and vessel form aspen trees in microscopy images. The model can analyze 32,640 x 25,920 pixels images and demonstrate effective cell detection and segmentation, achieving a $$\hbox \mAP\_\0.5-0.95\$$ mAP 0.5 - 0.95 of 78 %. To assess the model’s robustness, we examined fibers from a genetically modified tree line known for longer fibers. The outcomes were comparable to previous manual measurements. Additionally, we created a user-friendly web application for image analysis and provided the code for use on Google Colab. Conclusion By leveraging YOLOv8’s advances, this work provides a deep learning solution to enable efficient quantification and analysis of wood cells suitable for practical applications.

@article{demes_high-throughput_2023,
	title = {High-throughput characterization of cortical microtubule arrays response to anisotropic tensile stress},
	volume = {21},
	issn = {1741-7007},
	url = {https://doi.org/10.1186/s12915-023-01654-7},
	doi = {10.1186/s12915-023-01654-7},
	abstract = {Plants can perceive and respond to mechanical signals. For instance, cortical microtubule (CMT) arrays usually reorganize following the predicted maximal tensile stress orientation at the cell and tissue level. While research in the last few years has started to uncover some of the mechanisms mediating these responses, much remains to be discovered, including in most cases the actual nature of the mechanosensors. Such discovery is hampered by the absence of adequate quantification tools that allow the accurate and sensitive detection of phenotypes, along with high throughput and automated handling of large datasets that can be generated with recent imaging devices.},
	number = {1},
	urldate = {2023-07-14},
	journal = {BMC Biology},
	author = {Demes, Elsa and Verger, Stéphane},
	month = jul,
	year = {2023},
	keywords = {Image analysis, Mechanical stress, Microtubules, Plants},
	pages = {154},
}

Plants can perceive and respond to mechanical signals. For instance, cortical microtubule (CMT) arrays usually reorganize following the predicted maximal tensile stress orientation at the cell and tissue level. While research in the last few years has started to uncover some of the mechanisms mediating these responses, much remains to be discovered, including in most cases the actual nature of the mechanosensors. Such discovery is hampered by the absence of adequate quantification tools that allow the accurate and sensitive detection of phenotypes, along with high throughput and automated handling of large datasets that can be generated with recent imaging devices.

@article{atakhani_characterising_2022,
	title = {Characterising the mechanics of cell–cell adhesion in plants},
	volume = {3},
	issn = {2632-8828},
	url = {https://www.cambridge.org/core/journals/quantitative-plant-biology/article/characterising-the-mechanics-of-cellcell-adhesion-in-plants/9D165A5D6EA6F2B1927B9F0F38F88AAC},
	doi = {10/gpjfdn},
	abstract = {, 

Cell–cell adhesion is a fundamental feature of multicellular organisms. To ensure multicellular integrity, adhesion needs to be tightly controlled and maintained. In plants, cell–cell adhesion remains poorly understood. Here, we argue that to be able to understand how cell–cell adhesion works in plants, we need to understand and quantitatively measure the mechanics behind it. We first introduce cell–cell adhesion in the context of multicellularity, briefly explain the notions of adhesion strength, work and energy and present the current knowledge concerning the mechanisms of cell–cell adhesion in plants. Because still relatively little is known in plants, we then turn to animals, but also algae, bacteria, yeast and fungi, and examine how adhesion works and how it can be quantitatively measured in these systems. From this, we explore how the mechanics of cell adhesion could be quantitatively characterised in plants, opening future perspectives for understanding plant multicellularity.},
	language = {en},
	urldate = {2022-02-16},
	journal = {Quantitative Plant Biology},
	author = {Atakhani, Asal and Bogdziewiez, Léa and Verger, Stéphane},
	month = feb,
	year = {2022},
	keywords = {adhesion strength, cell–cell adhesion, multicellularity, plant, single cell, tissue},
}

, Cell–cell adhesion is a fundamental feature of multicellular organisms. To ensure multicellular integrity, adhesion needs to be tightly controlled and maintained. In plants, cell–cell adhesion remains poorly understood. Here, we argue that to be able to understand how cell–cell adhesion works in plants, we need to understand and quantitatively measure the mechanics behind it. We first introduce cell–cell adhesion in the context of multicellularity, briefly explain the notions of adhesion strength, work and energy and present the current knowledge concerning the mechanisms of cell–cell adhesion in plants. Because still relatively little is known in plants, we then turn to animals, but also algae, bacteria, yeast and fungi, and examine how adhesion works and how it can be quantitatively measured in these systems. From this, we explore how the mechanics of cell adhesion could be quantitatively characterised in plants, opening future perspectives for understanding plant multicellularity.

@incollection{louveaux_how_2022,
	address = {Cham},
	title = {How to {Do} the {Deconstruction} of {Bioimage} {Analysis} {Workflows}: {A} {Case} {Study} with {SurfCut}},
	isbn = {978-3-030-76394-7},
	shorttitle = {How to {Do} the {Deconstruction} of {Bioimage} {Analysis} {Workflows}},
	url = {https://doi.org/10.1007/978-3-030-76394-7_6},
	doi = {10.1007/978-3-030-76394-7_6},
	abstract = {Published bioimage analysis workflows are designed for a specific biology use case and often hidden in the material and methods section of a biology paper. The art of the bioimage analyst is to find these workflows, deconstruct them and tune them to a new use case by replacing or modifying components of the workflow and/or linking them to other workflows.},
	language = {en},
	urldate = {2024-10-09},
	booktitle = {Bioimage {Data} {Analysis} {Workflows} ‒ {Advanced} {Components} and {Methods}},
	publisher = {Springer International Publishing},
	author = {Louveaux, Marion and Verger, Stéphane},
	editor = {Miura, Kota and Sladoje, Nataša},
	year = {2022},
	pages = {115--146},
}

Published bioimage analysis workflows are designed for a specific biology use case and often hidden in the material and methods section of a biology paper. The art of the bioimage analyst is to find these workflows, deconstruct them and tune them to a new use case by replacing or modifying components of the workflow and/or linking them to other workflows.

@article{kohorn_effects_2021,
	title = {Effects of {Arabidopsis} wall associated kinase mutations on {ESMERALDA1} and elicitor induced {ROS}},
	volume = {16},
	issn = {1932-6203},
	url = {https://dx.plos.org/10.1371/journal.pone.0251922},
	doi = {10/gkct4r},
	abstract = {Angiosperm cell adhesion is dependent on interactions between pectin polysaccharides which make up a significant portion of the plant cell wall. Cell adhesion in Arabidopsis may also be regulated through a pectin-related signaling cascade mediated by a putative O-fucosyltransferase ESMERALDA1 (ESMD1), and the Epidermal Growth Factor (EGF) domains of the pectin binding Wall associated Kinases (WAKs) are a primary candidate substrate for ESMD1 activity. Genetic interactions between WAKs and ESMD1 were examined using a dominant hyperactive allele of WAK2,
              WAK2cTAP
              , and a mutant of the putative O-fucosyltransferase ESMD1. WAK2cTAP expression results in a dwarf phenotype and activation of the stress response and reactive oxygen species (ROS) production, while
              esmd1
              is a suppressor of a pectin deficiency induced loss of adhesion. Here we find that
              esmd1
              suppresses the WAK2cTAP dwarf and stress response phenotype, including ROS accumulation and gene expression. Additional analysis suggests that mutations of the potential WAK EGF O-fucosylation site also abate the WAK2cTAP phenotype, yet only evidence for an N-linked but not O-linked sugar addition can be found. Moreover, a
              WAK
              locus deletion allele has no effect on the ability of
              esmd1
              to suppress an adhesion deficiency, indicating WAKs and their modification are not a required component of the potential ESMD1 signaling mechanism involved in the control of cell adhesion. The WAK locus deletion does however affect the induction of ROS but not the transcriptional response induced by the elicitors Flagellin, Chitin and oligogalacturonides (OGs).},
	language = {en},
	number = {5},
	urldate = {2021-06-03},
	journal = {PLOS ONE},
	author = {Kohorn, Bruce D. and Greed, Bridgid E. and Mouille, Gregory and Verger, Stéphane and Kohorn, Susan L.},
	editor = {Zabotina, Olga A.},
	month = may,
	year = {2021},
	pages = {e0251922},
}

Angiosperm cell adhesion is dependent on interactions between pectin polysaccharides which make up a significant portion of the plant cell wall. Cell adhesion in Arabidopsis may also be regulated through a pectin-related signaling cascade mediated by a putative O-fucosyltransferase ESMERALDA1 (ESMD1), and the Epidermal Growth Factor (EGF) domains of the pectin binding Wall associated Kinases (WAKs) are a primary candidate substrate for ESMD1 activity. Genetic interactions between WAKs and ESMD1 were examined using a dominant hyperactive allele of WAK2, WAK2cTAP , and a mutant of the putative O-fucosyltransferase ESMD1. WAK2cTAP expression results in a dwarf phenotype and activation of the stress response and reactive oxygen species (ROS) production, while esmd1 is a suppressor of a pectin deficiency induced loss of adhesion. Here we find that esmd1 suppresses the WAK2cTAP dwarf and stress response phenotype, including ROS accumulation and gene expression. Additional analysis suggests that mutations of the potential WAK EGF O-fucosylation site also abate the WAK2cTAP phenotype, yet only evidence for an N-linked but not O-linked sugar addition can be found. Moreover, a WAK locus deletion allele has no effect on the ability of esmd1 to suppress an adhesion deficiency, indicating WAKs and their modification are not a required component of the potential ESMD1 signaling mechanism involved in the control of cell adhesion. The WAK locus deletion does however affect the induction of ROS but not the transcriptional response induced by the elicitors Flagellin, Chitin and oligogalacturonides (OGs).

@article{baral_external_2021,
	title = {External {Mechanical} {Cues} {Reveal} a {Katanin}-{Independent} {Mechanism} behind {Auxin}-{Mediated} {Tissue} {Bending} in {Plants}},
	volume = {56},
	issn = {15345807},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S1534580720309837},
	doi = {10/ghtbf9},
	language = {en},
	number = {1},
	urldate = {2021-06-03},
	journal = {Developmental Cell},
	author = {Baral, Anirban and Aryal, Bibek and Jonsson, Kristoffer and Morris, Emily and Demes, Elsa and Takatani, Shogo and Verger, Stéphane and Xu, Tongda and Bennett, Malcolm and Hamant, Olivier and Bhalerao, Rishikesh P.},
	month = jan,
	year = {2021},
	pages = {67--80.e3},
}

@article{malivert_feronia_2021,
	title = {{FERONIA} and microtubules independently contribute to mechanical integrity in the {Arabidopsis} shoot},
	volume = {19},
	issn = {1545-7885},
	url = {https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001454},
	doi = {10/gpkx26},
	abstract = {To survive, cells must constantly resist mechanical stress. In plants, this involves the reinforcement of cell walls, notably through microtubule-dependent cellulose deposition. How wall sensing might contribute to this response is unknown. Here, we tested whether the microtubule response to stress acts downstream of known wall sensors. Using a multistep screen with 11 mutant lines, we identify FERONIA (FER) as the primary candidate for the cell’s response to stress in the shoot. However, this does not imply that FER acts upstream of the microtubule response to stress. In fact, when performing mechanical perturbations, we instead show that the expected microtubule response to stress does not require FER. We reveal that the feronia phenotype can be partially rescued by reducing tensile stress levels. Conversely, in the absence of both microtubules and FER, cells appear to swell and burst. Altogether, this shows that the microtubule response to stress acts as an independent pathway to resist stress, in parallel to FER. We propose that both pathways are required to maintain the mechanical integrity of plant cells.},
	language = {en},
	number = {11},
	urldate = {2022-02-25},
	journal = {PLOS Biology},
	author = {Malivert, Alice and Erguvan, Özer and Chevallier, Antoine and Dehem, Antoine and Friaud, Rodrigue and Liu, Mengying and Martin, Marjolaine and Peyraud, Théophile and Hamant, Olivier and Verger, Stéphane},
	month = nov,
	year = {2021},
	keywords = {Anisotropy, Cellulose, Hypocotyl, Mechanical stress, Microtubules, Pavement cells, Plant cotyledon, Seedlings},
	pages = {e3001454},
}

To survive, cells must constantly resist mechanical stress. In plants, this involves the reinforcement of cell walls, notably through microtubule-dependent cellulose deposition. How wall sensing might contribute to this response is unknown. Here, we tested whether the microtubule response to stress acts downstream of known wall sensors. Using a multistep screen with 11 mutant lines, we identify FERONIA (FER) as the primary candidate for the cell’s response to stress in the shoot. However, this does not imply that FER acts upstream of the microtubule response to stress. In fact, when performing mechanical perturbations, we instead show that the expected microtubule response to stress does not require FER. We reveal that the feronia phenotype can be partially rescued by reducing tensile stress levels. Conversely, in the absence of both microtubules and FER, cells appear to swell and burst. Altogether, this shows that the microtubule response to stress acts as an independent pathway to resist stress, in parallel to FER. We propose that both pathways are required to maintain the mechanical integrity of plant cells.

@article{takatani_microtubule_2020,
	title = {Microtubule {Response} to {Tensile} {Stress} {Is} {Curbed} by {NEK6} to {Buffer} {Growth} {Variation} in the {Arabidopsis} {Hypocotyl}},
	volume = {30},
	issn = {09609822},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0960982220301974},
	doi = {10.1016/j.cub.2020.02.024},
	language = {en},
	number = {8},
	urldate = {2021-06-07},
	journal = {Current Biology},
	author = {Takatani, Shogo and Verger, Stéphane and Okamoto, Takashi and Takahashi, Taku and Hamant, Olivier and Motose, Hiroyasu},
	month = apr,
	year = {2020},
	pages = {1491--1503.e2},
}

@article{raggi_polar_2020,
	title = {Polar expedition: mechanisms for protein polar localization},
	volume = {53},
	issn = {13695266},
	shorttitle = {Polar expedition},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S1369526619301165},
	doi = {10.1016/j.pbi.2019.12.001},
	language = {en},
	urldate = {2021-06-07},
	journal = {Current Opinion in Plant Biology},
	author = {Raggi, Sara and Demes, Elsa and Liu, Sijia and Verger, Stéphane and Robert, Stéphanie},
	month = feb,
	year = {2020},
	pages = {134--140},
}

@article{fruleux_feeling_2019,
	title = {Feeling {Stressed} or {Strained}? {A} {Biophysical} {Model} for {Cell} {Wall} {Mechanosensing} in {Plants}},
	volume = {10},
	issn = {1664-462X},
	shorttitle = {Feeling {Stressed} or {Strained}?},
	url = {https://www.frontiersin.org/article/10.3389/fpls.2019.00757/full},
	doi = {10/gg484c},
	urldate = {2021-06-07},
	journal = {Frontiers in Plant Science},
	author = {Fruleux, Antoine and Verger, Stéphane and Boudaoud, Arezki},
	month = jun,
	year = {2019},
	pages = {757},
}

@article{erguvan_imagej_2019,
	title = {{ImageJ} {SurfCut}: a user-friendly pipeline for high-throughput extraction of cell contours from {3D} image stacks},
	volume = {17},
	issn = {1741-7007},
	shorttitle = {{ImageJ} {SurfCut}},
	url = {https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-019-0657-1},
	doi = {10/gf2hww},
	language = {en},
	number = {1},
	urldate = {2021-06-07},
	journal = {BMC Biology},
	author = {Erguvan, Özer and Louveaux, Marion and Hamant, Olivier and Verger, Stéphane},
	month = dec,
	year = {2019},
	pages = {38},
}

@article{verger_mechanical_2019,
	title = {Mechanical {Conflicts} in {Twisting} {Growth} {Revealed} by {Cell}-{Cell} {Adhesion} {Defects}},
	volume = {10},
	issn = {1664-462X},
	url = {https://www.frontiersin.org/article/10.3389/fpls.2019.00173/full},
	doi = {10/gkf56m},
	urldate = {2021-06-07},
	journal = {Frontiers in Plant Science},
	author = {Verger, Stéphane and Liu, Mengying and Hamant, Olivier},
	month = feb,
	year = {2019},
	pages = {173},
}

@article{verger_tension-adhesion_2018,
	title = {A tension-adhesion feedback loop in plant epidermis},
	volume = {7},
	issn = {2050-084X},
	url = {https://doi.org/10.7554/eLife.34460},
	doi = {10/gdd8s2},
	abstract = {Mechanical forces have emerged as coordinating signals for most cell functions. Yet, because forces are invisible, mapping tensile stress patterns in tissues remains a major challenge in all kingdoms. Here we take advantage of the adhesion defects in the Arabidopsis mutant quasimodo1 (qua1) to deduce stress patterns in tissues. By reducing the water potential and epidermal tension in planta, we rescued the adhesion defects in qua1, formally associating gaping and tensile stress patterns in the mutant. Using suboptimal water potential conditions, we revealed the relative contributions of shape- and growth-derived stress in prescribing maximal tension directions in aerial tissues. Consistently, the tension patterns deduced from the gaping patterns in qua1 matched the pattern of cortical microtubules, which are thought to align with maximal tension, in wild-type organs. Conversely, loss of epidermis continuity in the qua1 mutant hampered supracellular microtubule alignments, revealing that coordination through tensile stress requires cell-cell adhesion.},
	urldate = {2021-06-07},
	journal = {eLife},
	publisher = {eLife Sciences Publications, Ltd},
	author = {Verger, Stéphane and Long, Yuchen and Boudaoud, Arezki and Hamant, Olivier},
	editor = {Hardtke, Christian S and Bergmann, Dominique C},
	month = apr,
	year = {2018},
	keywords = {cell adhesion, mechanical stress, microtubules, plant organs},
	pages = {e34460},
}

Mechanical forces have emerged as coordinating signals for most cell functions. Yet, because forces are invisible, mapping tensile stress patterns in tissues remains a major challenge in all kingdoms. Here we take advantage of the adhesion defects in the Arabidopsis mutant quasimodo1 (qua1) to deduce stress patterns in tissues. By reducing the water potential and epidermal tension in planta, we rescued the adhesion defects in qua1, formally associating gaping and tensile stress patterns in the mutant. Using suboptimal water potential conditions, we revealed the relative contributions of shape- and growth-derived stress in prescribing maximal tension directions in aerial tissues. Consistently, the tension patterns deduced from the gaping patterns in qua1 matched the pattern of cortical microtubules, which are thought to align with maximal tension, in wild-type organs. Conversely, loss of epidermis continuity in the qua1 mutant hampered supracellular microtubule alignments, revealing that coordination through tensile stress requires cell-cell adhesion.

@article{verger_image_2018,
	title = {An {Image} {Analysis} {Pipeline} to {Quantify} {Emerging} {Cracks} in {Materials} or {Adhesion} {Defects} in {Living} {Tissues}},
	volume = {8},
	issn = {2331-8325},
	url = {https://bio-protocol.org/e3036},
	doi = {10/gkf56f},
	language = {en},
	number = {19},
	urldate = {2021-06-07},
	journal = {BIO-PROTOCOL},
	author = {Verger, Stéphane and Cerutti, Guillaume and Hamant, Olivier},
	year = {2018},
}

@article{verger_plant_2018,
	title = {Plant {Physiology}: {FERONIA} {Defends} the {Cell} {Walls} against {Corrosion}},
	volume = {28},
	issn = {0960-9822},
	shorttitle = {Plant {Physiology}},
	url = {https://www.sciencedirect.com/science/article/pii/S0960982218300769},
	doi = {10/gc3gx6},
	abstract = {A new study uncovers the role of wall sensing and remodeling in the plant response to salt stress, identifying the FERONIA receptor kinase as a key player in that process, likely through direct sensing of cell wall pectins.},
	language = {en},
	number = {5},
	urldate = {2021-06-07},
	journal = {Current Biology},
	author = {Verger, Stéphane and Hamant, Olivier},
	month = mar,
	year = {2018},
	pages = {R215--R217},
}

A new study uncovers the role of wall sensing and remodeling in the plant response to salt stress, identifying the FERONIA receptor kinase as a key player in that process, likely through direct sensing of cell wall pectins.

@article{sapala_why_2018,
	title = {Why plants make puzzle cells, and how their shape emerges},
	volume = {7},
	issn = {2050-084X},
	url = {https://doi.org/10.7554/eLife.32794},
	doi = {10/gc3w3z},
	abstract = {The shape and function of plant cells are often highly interdependent. The puzzle-shaped cells that appear in the epidermis of many plants are a striking example of a complex cell shape, however their functional benefit has remained elusive. We propose that these intricate forms provide an effective strategy to reduce mechanical stress in the cell wall of the epidermis. When tissue-level growth is isotropic, we hypothesize that lobes emerge at the cellular level to prevent formation of large isodiametric cells that would bulge under the stress produced by turgor pressure. Data from various plant organs and species support the relationship between lobes and growth isotropy, which we test with mutants where growth direction is perturbed. Using simulation models we show that a mechanism actively regulating cellular stress plausibly reproduces the development of epidermal cell shape. Together, our results suggest that mechanical stress is a key driver of cell-shape morphogenesis.},
	urldate = {2021-06-07},
	journal = {eLife},
	publisher = {eLife Sciences Publications, Ltd},
	author = {Sapala, Aleksandra and Runions, Adam and Routier-Kierzkowska, Anne-Lise and Das Gupta, Mainak and Hong, Lilan and Hofhuis, Hugo and Verger, Stéphane and Mosca, Gabriella and Li, Chun-Biu and Hay, Angela and Hamant, Olivier and Roeder, Adrienne HK and Tsiantis, Miltos and Prusinkiewicz, Przemyslaw and Smith, Richard S},
	editor = {McCormick, Sheila},
	month = feb,
	year = {2018},
	keywords = {growth, modelling, morphogenesis, organ shape, pavement cells, plant development},
	pages = {e32794},
}

The shape and function of plant cells are often highly interdependent. The puzzle-shaped cells that appear in the epidermis of many plants are a striking example of a complex cell shape, however their functional benefit has remained elusive. We propose that these intricate forms provide an effective strategy to reduce mechanical stress in the cell wall of the epidermis. When tissue-level growth is isotropic, we hypothesize that lobes emerge at the cellular level to prevent formation of large isodiametric cells that would bulge under the stress produced by turgor pressure. Data from various plant organs and species support the relationship between lobes and growth isotropy, which we test with mutants where growth direction is perturbed. Using simulation models we show that a mechanism actively regulating cellular stress plausibly reproduces the development of epidermal cell shape. Together, our results suggest that mechanical stress is a key driver of cell-shape morphogenesis.

@article{verger_cell_2016,
	title = {Cell adhesion in plants is under the control of putative {O}-fucosyltransferases},
	volume = {143},
	issn = {0950-1991},
	url = {https://doi.org/10.1242/dev.132308},
	doi = {10/f9n5bb},
	abstract = {Cell-to-cell adhesion in plants is mediated by the cell wall and the presence of a pectin-rich middle lamella. However, we know very little about how the plant actually controls and maintains cell adhesion during growth and development and how it deals with the dynamic cell wall remodeling that takes place. Here we investigate the molecular mechanisms that control cell adhesion in plants. We carried out a genetic suppressor screen and a genetic analysis of cell adhesion-defective Arabidopsis thaliana mutants. We identified a genetic suppressor of a cell adhesion defect affecting a putative O-fucosyltransferase. Furthermore, we show that the state of cell adhesion is not directly linked with pectin content in the cell wall but instead is associated with altered pectin-related signaling. Our results suggest that cell adhesion is under the control of a feedback signal from the state of the pectin in the cell wall. Such a mechanism could be necessary for the control and maintenance of cell adhesion during growth and development.},
	number = {14},
	urldate = {2021-06-07},
	journal = {Development},
	author = {Verger, Stéphane and Chabout, Salem and Gineau, Emilie and Mouille, Grégory},
	month = jul,
	year = {2016},
	pages = {2536--2540},
}

Cell-to-cell adhesion in plants is mediated by the cell wall and the presence of a pectin-rich middle lamella. However, we know very little about how the plant actually controls and maintains cell adhesion during growth and development and how it deals with the dynamic cell wall remodeling that takes place. Here we investigate the molecular mechanisms that control cell adhesion in plants. We carried out a genetic suppressor screen and a genetic analysis of cell adhesion-defective Arabidopsis thaliana mutants. We identified a genetic suppressor of a cell adhesion defect affecting a putative O-fucosyltransferase. Furthermore, we show that the state of cell adhesion is not directly linked with pectin content in the cell wall but instead is associated with altered pectin-related signaling. Our results suggest that cell adhesion is under the control of a feedback signal from the state of the pectin in the cell wall. Such a mechanism could be necessary for the control and maintenance of cell adhesion during growth and development.

@article{galletti_developing_2016,
	title = {Developing a ‘thick skin’: a paradoxical role for mechanical tension in maintaining epidermal integrity?},
	volume = {143},
	issn = {0950-1991},
	shorttitle = {Developing a ‘thick skin’},
	url = {https://doi.org/10.1242/dev.132837},
	doi = {10.1242/dev.132837},
	abstract = {Plant aerial epidermal tissues, like animal epithelia, act as load-bearing layers and hence play pivotal roles in development. The presence of tension in the epidermis has morphogenetic implications for organ shapes but it also constantly threatens the integrity of this tissue. Here, we explore the multi-scale relationship between tension and cell adhesion in the plant epidermis, and we examine how tensile stress perception may act as a regulatory input to preserve epidermal tissue integrity and thus normal morphogenesis. From this, we identify parallels between plant epidermal and animal epithelial tissues and highlight a list of unexplored questions for future research.},
	number = {18},
	urldate = {2021-10-14},
	journal = {Development},
	author = {Galletti, Roberta and Verger, Stéphane and Hamant, Olivier and Ingram, Gwyneth C.},
	month = sep,
	year = {2016},
	pages = {3249--3258},
}

Plant aerial epidermal tissues, like animal epithelia, act as load-bearing layers and hence play pivotal roles in development. The presence of tension in the epidermis has morphogenetic implications for organ shapes but it also constantly threatens the integrity of this tissue. Here, we explore the multi-scale relationship between tension and cell adhesion in the plant epidermis, and we examine how tensile stress perception may act as a regulatory input to preserve epidermal tissue integrity and thus normal morphogenesis. From this, we identify parallels between plant epidermal and animal epithelial tissues and highlight a list of unexplored questions for future research.

@article{geshi_galactosyltransferase_2013,
	title = {A galactosyltransferase acting on arabinogalactan protein glycans is essential for embryo development in {Arabidopsis}},
	issn = {09607412},
	url = {http://doi.wiley.com/10.1111/tpj.12281},
	doi = {10/gkgdks},
	language = {en},
	urldate = {2021-06-08},
	journal = {The Plant Journal},
	author = {Geshi, Naomi and Johansen, Jorunn N. and Dilokpimol, Adiphol and Rolland, Aurélia and Belcram, Katia and Verger, Stéphane and Kotake, Toshihisa and Tsumuraya, Yoichi and Kaneko, Satoshi and Tryfona, Theodora and Dupree, Paul and Scheller, Henrik V. and Höfte, Herman and Mouille, Gregory},
	month = aug,
	year = {2013},
	pages = {n/a--n/a},
}