Biology subjects

Verger, S.

Publications and source records attributed to Verger, S..

9 recordsLinked to original sources

bioRxiv2026

CO2-concentrating nanoparticles drive progressive photosynthetic and cell-wall remodelling in Arabidopsis thaliana cells

Plant cells offer a distinctive platform for biohybrid engineering because they combine growth and proliferation with photosynthetic carbon acquisition and the continuous fabrication of structurally complex biomass. Harnessing these capabilities could enable living systems in which synthetic functionality develops together with cellular physiology and material organization. Yet nanomaterial engineering of proliferating plant cell populations remains largely unexplored. Here, we establish a biohybrid system combining photosynthetically active Arabidopsis thaliana suspension cells with chitosan-modified polyethyleneimine (gPEI-Chi) nanoparticles, a synthetic CO2-concentrating nanomaterial. By supplying fresh nanoparticles at each subculture, newly generated cell populations were successively functionalized, driving progressive changes in cellular and multicellular phenotypes. Nanoparticle functionalization reduced net headspace CO2 accumulation, increased chlorophyll content and induced stage-dependent reorganization of photosynthetic function and carbon-handling pathways. These physiological changes were accompanied by altered cell wall regeneration and progressive remodelling of cell wall composition, spatial organization and ultrastructure, ultimately promoting more cohesive multicellular aggregates. Our findings establish successive nanomaterial functionalization as a strategy to steer the evolving physiology and structural organization of proliferating plant cell populations, opening opportunities for plant biohybrid systems and engineered living materials.

plant biology↗

bioRxiv2026

Plant cell-based 4D engineered living materials

Engineered living materials (ELMs) seek to bridge the gap between static engineered matter and dynamic biological systems. Photosynthetic ELMs have emerged as a promising route towards autonomous and sustainable material systems; however, they remain largely based on microorganisms or isolated organelles, whereas the potential of living plant cells as multifunctional, adaptive building blocks remains largely unexplored. Here we establish plant cells as a distinct chassis for engineered living materials and demonstrate that their intrinsic metabolic plasticity, cell-wall biochemistry and mechanics can be harnessed to create adaptive, evolvable and programmable materials. Using Arabidopsis thaliana suspension cells and printable pectin-alginate bioinks, we fabricate two- and three-dimensional living materials that support growth, metabolic plasticity and, long-term viability. Non-photosynthetic ELMs undergo light-induced metabolic reprogramming to acquire photosynthetic activity, demonstrating adaptive behaviour, while continuous cell growth dynamically remodels the mechanical properties of the material, enabling evolution of material properties through intrinsic biological processes. We further exploit endogenous cell wall peroxidases to catalyse the biofabrication of conducting polymers, enabling programmable acquisition of electrochemical functionality without genetic modification. By integrating living plant cells with auxetic and honeycomb architectures, we show that biological activity and structural design jointly determine emergent mechanical behaviour, revealing a principle of geometry-dependent biological reinforcement for living mechanical metamaterials. Centimetre-scale plant ELMs retain robust photosynthetic activity, with electron transport rates approaching those of native Arabidopsis tissues despite the absence of leaf architecture. Together, these findings establish plant cells as versatile building blocks for multifunctional living materials and lay the foundation for self-powered autonomous materials with potential applications in soft robotics, bioelectronics, and carbon capture.

bioengineering↗

bioRxiv2026

Mechanical coordination of counter-gradient growth maintains organ curvature in apical hooks

How growing tissues convert mechanical tension into signals that stabilize form remains a central question in morphogenesis. Curved organ shapes in plants arise from differential growth, yet how such curvature is actively maintained while organs continuously grow remains poorly understood. In etiolated seedlings, the apical hook provides a tractable model to dissect this process, as its curvature is stably maintained over extended periods despite ongoing cell expansion. Using quantitative imaging and computational modeling, we show that antagonistic growth gradients at apical and basal regions are both necessary and sufficient to maintain hook curvature, with cuticle integrity being critical for establishing these counter-gradients. Mechanical cues linked to cuticle structure, coupled with apoplastic reactive oxygen species (ROS), coordinate cellular growth anisotropy, and disruptions in cuticle biosynthesis trigger defective hook development. These findings reveal that the apical hook curve maintenance is not a simple switch between growth promotion and repression, but a highly dynamic, tightly regulated process where mechanical and biochemical signals coordinate organ-scale morphogenesis, fundamentally reshaping how we understand developmental growth.

plant biology↗

bioRxiv2025

Outer epidermal edges mediate cell-cell adhesion for tissue integrity in plants

Cell-cell adhesion in plants is generally thought to be primarily mediated by the middle lamella, a supposedly thin adhesive layer of the cell wall. Here, we challenge this view. Through computational simulation we found that outer edges of cellular interfaces of the epidermis are hotspot for cell separating tensile stress. Characterization of the ultrastructure of those edges in planta revealed that they are locally thickened regions that harbor cellulose lamellae and pectin-based structural continuity across adjacent cells. We confirmed their dominant role for adhesion by studying mutants where those edges are defective and through direct mechanical testing. This reveals the key role of outer epidermal cell edges, rather than the middle lamella, in mediating cell-cell adhesion for tissue integrity in plants.

plant biology↗

bioRxiv2025

The Q-Warg Pipeline: A Robust and Versatile Workflow for Quantitative Analysis of Protoplast Culture Conditions

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, due to the absence of a CW, protoplasts are not considered "true" plant cells and 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 available and user-friendly solution for robust and unbiased characterization of protoplasts culture. The quantitative data generated by the pipeline may be useful in the future to decipher the mechanisms regulating protoplast viability and regeneration. Significance statementSeveral fields of plant biology, ranging from biotechnology to biomechanics, have recently regained a strong interest in using and studying protoplasts and single cells. Here, we developed a widely accessible quantitative workflow to characterize cell culture recovery after protoplasting along with the demonstration of its usefulness and versatility in various cases. We hope this tool can help other research groups to streamline the procedure needed to establish single plant cell approaches in their lab.

plant biology↗

bioRxiv2024

Rhamnogalacturonan-II dimerization deficiency impairs the coordination between growth and adhesion maintenance in plants

Cell adhesion is a fundamental feature of multicellular organisms. In plants, cell adhesion is mediated by the cell wall, but the control and maintenance of cell adhesion during growth and development remains poorly understood1. Here we uncover the role of a component of the cell wall, rhamnogalacturonan-II (RG-II) and its capacity to crosslink in the presence of Boron2, as a key regulator of plant cell adhesion maintenance. We show that RG-II dimerization deficiency leads to cell adhesion defects. Importantly, the analysis of mur1 mutants with RG-II dimerization defects uncovers a cell adhesion pathway that is distinct from that identified by the analysis of pectin deficient mutants3. We found that mutations in two cell wall integrity sensors, RESISTANCE TO FUSARIUM OXYSPORUM 1 and RECEPTOR-LIKE PROTEIN 44, as well as supplementation with the hormone brassinosteroid can partially rescue the adhesion defects associated with RG-II dimerization deficiency. We also show that adhesion defects associated with RG-II dimerization deficiency are related to increased epidermal tension as well as decreased homogalacturonan levels in the cell wall, which can also be rescued by supplementation with brassinosteroid. Overall, we propose that RG-II dimerization defects alter cell adhesion directly (reduced crosslinks) but also indirectly through cell wall integrity sensing, brassinosteroid signalling, cell wall remodelling and cell layer growth coordination. Thus, our results uncover the involvement of cell wall integrity sensors and hormonal signalling in the coordination between growth and adhesion maintenance in plants, which is a key feature for complex multicellularity. Highlights- RG-II dimerization is required for cell-cell adhesion in plants. - Cell wall integrity sensors and brassinosteroid signalling mediate cell adhesion downstream of RG-II dimerization. - Cell detachments due to defective RG-II dimerization are caused by weakened middle lamella and higher tissue tension.

plant biology↗

bioRxiv2023

Cell wall integrity modulates a PHYTOCHROME-INTERACTING FACTOR (PIF) - HOOKLESS1 (HLS1) signalling module controlling apical hook formation in Arabidopsis.

Etiolated seedlings of dicots form an apical hook to protect the meristems during soil emergence. Hook formation is the result of differential growth on both sides of the hypocotyl apex and is tightly controlled by environmental cues and hormones, among which auxin and gibberellins (GAs) are the main contributors. Cell expansion is tightly regulated by the cell wall, but whether and how feedback from this structure contributes to hook development is still unclear. Here we show that etiolated seedlings of the 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 FACTOR 4 and 5 (PIF4/5), positive regulators of hook formation, and accumulate reduced levels of the active gibberellin GA4. Treatment of wild-type seedlings with the cellulose inhibitor isoxaben (isx) also prevents hook development and represses HLS1 expression and PIF4 accumulation. Moreover, isx stabilizes the DELLA protein REPRESSOR OF ga1-3 (RGA), which inhibits HLS1 expression and hook formation. Exogenous GAs or HLS1 overexpression partially restore hook development in isx-treated seedlings. Notably, agar concentration in the medium restores, both in qua2 and isx-treated seedlings, hook development and WT-like levels of PIFs and HLS1. We propose that turgor-dependent signals link changes in cell wall integrity to the PIF4/5-HLS1 signalling module to repress differential cell elongation during hook formation. Significance statementCell wall integrity modulates apical hook development through poorly understood mechanisms. We show here that, in Arabidopsis, repression of hook formation by either mutations in pectin biosynthesis or by isoxaben treatment is at least partially mediated by the downregulation of a gibberellin-controlled signalling module that comprises PIF4/5 and HLS1. Our results indicate that the signals derived from changes in the cell wall can modulate hormone-mediated pathways to control asymmetric growth during plant development.

plant biology↗

bioRxiv2021

Turning plants from passive to active material: FERONIA and microtubules independently contribute to mechanical feedback

To survive, cells must constantly resist mechanical stress. In plants, this involves the reinforcement of cell walls, notably through microtubule-dependent cellulose deposition, and thus wall sensing. Several receptor-like kinases have been proposed to act as mechanosensors. Here we tested whether the microtubule response to stress acts downstream of known wall sensors. Using a multi-step screen with eleven mutant lines, we identify FERONIA as the primary candidate for controlling the microtubule response to stress. However, when performing mechanical perturbations, we show that the microtubule response to stress can be independent from 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 swell and burst like soap bubbles. 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 key components to turn plant cells from passive to active material.

plant biology↗

bioRxiv2020

External mechanical cues reveal core molecular pathway behind tissue bending in plants

Tissue folding is a central building block of plant and animal morphogenesis. In dicotyledonous plants, hypocotyl folds to form hook after seedling germination that protects their aerial stem cell niche during emergence from soil. Auxin response factors and auxin transport are classically thought to play a key role in this process. Here we show that the microtubule-severing enzyme katanin contributes to hook formation. However, by exposing hypocotyls to external mechanical cues mimicking the natural soil environment, we reveal that auxin response factors ARF7/ARF19, auxin influx carriers, and katanin are dispensable for apical hook formation, indicating that these factors primarily play the role of catalyzers of tissue bending in the absence of external mechanical cues. Instead, our results reveal the key roles of the non-canonical TMK-mediated auxin pathway, PIN efflux carriers and cellulose microfibrils as components of the core pathway behind hook formation in presence or absence of external mechanical cues.

plant biology↗