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Bou Daher F, Serra L, Carter R, Jönsson H, Robinson S, Meyerowitz EM, Gray WM. Xyloglucan deficiency leads to a reduction in turgor pressure and changes in cell wall properties, affecting early seedling establishment. Curr Biol 2024:S0960-9822(24)00456-1. [PMID: 38677280 DOI: 10.1016/j.cub.2024.04.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/17/2024] [Accepted: 04/08/2024] [Indexed: 04/29/2024]
Abstract
Xyloglucan is believed to play a significant role in cell wall mechanics of dicot plants. Surprisingly, Arabidopsis plants defective in xyloglucan biosynthesis exhibit nearly normal growth and development. We investigated a mutant line, cslc-Δ5, lacking activity in all five Arabidopsis cellulose synthase like-C (CSLC) genes responsible for xyloglucan backbone biosynthesis. We observed that this xyloglucan-deficient line exhibited reduced cellulose crystallinity and increased pectin levels, suggesting the existence of feedback mechanisms that regulate wall composition to compensate for the absence of xyloglucan. These alterations in cell wall composition in the xyloglucan-absent plants were further linked to a decrease in cell wall elastic modulus and rupture stress, as observed through atomic force microscopy (AFM) and extensometer-based techniques. This raised questions about how plants with such modified cell wall properties can maintain normal growth. Our investigation revealed two key factors contributing to this phenomenon. First, measurements of turgor pressure, a primary driver of plant growth, revealed that cslc-Δ5 plants have reduced turgor, preventing the compromised walls from bursting while still allowing growth to occur. Second, we discovered the conservation of elastic asymmetry (ratio of axial to transverse wall elasticity) in the mutant, suggesting an additional mechanism contributing to the maintenance of normal growth. This novel feedback mechanism between cell wall composition and mechanical properties, coupled with turgor pressure regulation, plays a central role in the control of plant growth and is critical for seedling establishment in a mechanically challenging environment by affecting shoot emergence and root penetration.
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Affiliation(s)
- Firas Bou Daher
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN 55108, USA; Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK.
| | - Leo Serra
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK
| | - Ross Carter
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK
| | - Henrik Jönsson
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK
| | - Sarah Robinson
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK
| | - Elliot M Meyerowitz
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK; Howard Hughes Medical Institute and Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - William M Gray
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN 55108, USA
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2
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Cong X, Li S, Hu D. Stomatal aperture dynamics coupling mechanically passive and ionically active mechanisms. Plant Cell Environ 2024; 47:106-121. [PMID: 37743707 DOI: 10.1111/pce.14726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 07/16/2023] [Accepted: 09/10/2023] [Indexed: 09/26/2023]
Abstract
Stomata are the key nodes linking photosynthesis and transpiration. By regulating the opening degree of stomata, plants successively achieve the balance between water loss and carbon dioxide acquisition. The dynamic behaviour of stomata is an important cornerstone of plant adaptability. Though there have been miscellaneous experimental results on stomata and their constituent cells, the guard cells and the subsidiary cells, current theory of stomata regulation is far from clear and unified. In this work, we develop an integrated model to describe the stomatal dynamics of seed plants based on existing experimental results. The model includes three parts: (1) a passive mechanical model of the stomatal aperture as a bivariate function of the guard-cell turgor and the subsidiary-cell turgor; (2) an active regulation model with a target ion-content in guard cells as a function of their water potential; and (3) a dynamical model for the movement of potassium ions and water content. Our model has been used to reproduce abundant experimental phenomena semi-quantitatively. With accurately measured parameters, our model can also be used to predict stomatal responses to changes of environmental conditions.
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Affiliation(s)
- Xue Cong
- School of Mathematical Sciences, Institute of Natural Sciences, and MOE-LSC, Shanghai Jiao Tong University, Shanghai, China
| | - Sien Li
- Center for Agricultural Water Research in China, Agricultural University, Beijing, China
- Shiyanghe Experimental Station for Improving Water Use Efficiency in Agriculture, Ministry of Agriculture and Rural Affairs, Wuwei, China
| | - Dan Hu
- School of Mathematical Sciences, Institute of Natural Sciences, and MOE-LSC, Shanghai Jiao Tong University, Shanghai, China
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3
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Kanahama T, Sato M. Mechanics-based classification rule for plants. Proc Natl Acad Sci U S A 2023; 120:e2308319120. [PMID: 37801474 PMCID: PMC10576094 DOI: 10.1073/pnas.2308319120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 08/28/2023] [Indexed: 10/08/2023] Open
Abstract
The height of thick and solid plants, such as woody plants, is proportional to two-thirds of the power of their diameter at breast height. However, this rule cannot be applied to herbaceous plants that are thin and soft because the mechanisms supporting their bodies are fundamentally different. This study aims to clarify the rigidity control mechanism resulting from turgor pressure caused by internal water in herbaceous plants to formulate the corresponding scaling law. We modeled a herbaceous plant as a cantilever with the ground side as a fixed end, and the greatest height was formulated considering the axial tension force from the turgor pressure. The scaling law describing the relationship between the height and diameter in terms of the turgor pressure was theoretically derived. Moreover, we proposed a plant classification rule based on stress distribution.
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Affiliation(s)
- Tohya Kanahama
- Graduate School of Engineering, Hokkaido University, Sapporo060-8628, Japan
| | - Motohiro Sato
- Faculty of Engineering, Hokkaido University, Sapporo060-8628, Japan
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4
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Lemière J, Chang F. Quantifying turgor pressure in budding and fission yeasts based upon osmotic properties. bioRxiv 2023:2023.06.07.544129. [PMID: 37333400 PMCID: PMC10274794 DOI: 10.1101/2023.06.07.544129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Walled cells, such as plants, fungi, and bacteria cells, possess a high internal hydrostatic pressure, termed turgor pressure, that drives volume growth and contributes to cell shape determination. Rigorous measurement of turgor pressure, however, remains challenging, and reliable quantitative measurements, even in budding yeast are still lacking. Here, we present a simple and robust experimental approach to access turgor pressure in yeasts based upon the determination of isotonic concentration using protoplasts as osmometers. We propose three methods to identify the isotonic condition - 3D cell volume, cytoplasmic fluorophore intensity, and mobility of a cytGEMs nano-rheology probe - that all yield consistent values. Our results provide turgor pressure estimates of 1.0 ± 0.1 MPa for S. pombe, 0.49 ± 0.01 MPa for S. japonicus, 0.5 ± 0.1 MPa for S. cerevisiae W303a and 0.31 ± 0.03 MPa for S. cerevisiae BY4741. Large differences in turgor pressure and nano-rheology measurements between the S. cerevisiae strains demonstrate how fundamental biophysical parameters can vary even among wildtype strains of the same species. These side-by-side measurements of turgor pressure in multiple yeast species provide critical values for quantitative studies on cellular mechanics and comparative evolution.
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Affiliation(s)
- Joël Lemière
- Department of Cell and Tissue Biology, University of San Francisco, CA, USA
| | - Fred Chang
- Department of Cell and Tissue Biology, University of San Francisco, CA, USA
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5
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Crabos A, Huang Y, Boursat T, Maurel C, Ruffel S, Krouk G, Boursiac Y. Distinct early transcriptional regulations by turgor and osmotic potential in the roots of Arabidopsis. J Exp Bot 2023; 74:5917-5930. [PMID: 37603421 DOI: 10.1093/jxb/erad307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 07/28/2023] [Indexed: 08/23/2023]
Abstract
In a context of climate change, deciphering signaling pathways driving plant adaptation to drought, changes in water availability, and salt is key. A crossing point of these plant stresses is their impact on plant water potential (Ψ), a composite physico-chemical variable reflecting the availability of water for biological processes such as plant growth and stomatal aperture. The Ψ of plant cells is mainly driven by their turgor and osmotic pressures. Here we investigated the effect of a variety of osmotic treatments on the roots of Arabidopsis plants grown in hydroponics. We used, among others, a permeating solute as a way to differentiate variations on turgor from variations in osmotic pressure. Measurement of cortical cell turgor pressure with a cell pressure probe allowed us to monitor the intensity of the treatments and thereby preserve the cortex from plasmolysis. Transcriptome analyses at an early time point (15 min) showed specific and quantitative transcriptomic responses to both osmotic and turgor pressure variations. Our results highlight how water-related biophysical parameters can shape the transcriptome of roots under stress and provide putative candidates to explore further the early perception of water stress in plants.
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Affiliation(s)
- Amandine Crabos
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Yunji Huang
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Thomas Boursat
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
- Laboratoire de Mécanique et Génie Civil (LMGC), Univ Montpellier, CNRS, Montpellier, France
| | - Christophe Maurel
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Sandrine Ruffel
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Gabriel Krouk
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Yann Boursiac
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
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6
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Ortega JKE. Theoretical Analyses of Turgor Pressure during Stress Relaxation and Water Uptake, and after Changes in Expansive Growth Rate When Water Uptake Is Normal and Reduced. Plants (Basel) 2023; 12:plants12091891. [PMID: 37176947 PMCID: PMC10181280 DOI: 10.3390/plants12091891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/28/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023]
Abstract
Turgor pressure provides the force needed to stress and deform the cell walls of plants, algae, and fungi during expansive growth. However, turgor pressure plays another subtle but equally important role in expansive growth of walled cells: it connects the two biophysical processes of water uptake and wall deformation to ensure that the volumetric rates of water uptake and enlargement of the cell wall chamber are equal. In this study, the role of turgor pressure as a 'connector' is investigated analytically by employing validated and established biophysical equations. The objective is to determine the effect of 'wall loosening' on the magnitude of turgor pressure. It is known that an increase or decrease in turgor pressure and/or wall loosening rate increases or decreases the expansive growth rate, respectively. Interestingly, it is shown that an increase in the wall loosening rate decreases the turgor pressure slightly, thus reducing the effect of wall loosening on increasing the expansive growth rate. Other analyses reveal that reducing the rate of water uptake results in a larger decrease in turgor pressure with the same increase in wall loosening rate, which further reduces the effect of wall loosening on increasing the expansive growth rate.
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Affiliation(s)
- Joseph K E Ortega
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80217-3364, USA
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7
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Ali O, Cheddadi I, Landrein B, Long Y. Revisiting the relationship between turgor pressure and plant cell growth. New Phytol 2023; 238:62-69. [PMID: 36527246 DOI: 10.1111/nph.18683] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
Growth is central to plant morphogenesis. Plant cells are encased in rigid cell walls, and they must overcome physical confinement to grow to specific sizes and shapes. Cell wall tension and turgor pressure are the main mechanical components impacting plant cell growth. Cell wall mechanics has been the focus of most plant biomechanical studies, and turgor pressure was often considered as a constant and largely passive component. Nevertheless, it is increasingly accepted that turgor pressure plays a significant role in plant growth. Numerous theoretical and experimental studies suggest that turgor pressure can be both spatially inhomogeneous and actively modulated during morphogenesis. Here, we revisit the pressure-growth relationship by reviewing recent advances in investigating the interactions between cellular/tissular pressure and growth.
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Affiliation(s)
- Olivier Ali
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, Lyon Cedex 07, 69364, France
| | - Ibrahim Cheddadi
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, Lyon Cedex 07, 69364, France
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Benoit Landrein
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, Lyon Cedex 07, 69364, France
| | - Yuchen Long
- Department of Biological Sciences, The National University of Singapore, Singapore, 117543, Singapore
- Mechanobiology Institute, The National University of Singapore, Singapore, 117411, Singapore
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8
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Costa ÁVL, Oliveira TFDC, Posso DA, Reissig GN, Parise AG, Barros WS, Souza GM. Systemic Signals Induced by Single and Combined Abiotic Stimuli in Common Bean Plants. Plants (Basel) 2023; 12:924. [PMID: 36840271 PMCID: PMC9964927 DOI: 10.3390/plants12040924] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/10/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
To survive in a dynamic environment growing fixed to the ground, plants have developed mechanisms for monitoring and perceiving the environment. When a stimulus is perceived, a series of signals are induced and can propagate away from the stimulated site. Three distinct types of systemic signaling exist, i.e., (i) electrical, (ii) hydraulic, and (iii) chemical, which differ not only in their nature but also in their propagation speed. Naturally, plants suffer influences from two or more stimuli (biotic and/or abiotic). Stimuli combination can promote the activation of new signaling mechanisms that are explicitly activated, as well as the emergence of a new response. This study evaluated the behavior of electrical (electrome) and hydraulic signals after applying simple and combined stimuli in common bean plants. We used simple and mixed stimuli applications to identify biochemical responses and extract information from the electrical and hydraulic patterns. Time series analysis, comparing the conditions before and after the stimuli and the oxidative responses at local and systemic levels, detected changes in electrome and hydraulic signal profiles. Changes in electrome are different between types of stimulation, including their combination, and systemic changes in hydraulic and oxidative dynamics accompany these electrical signals.
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Affiliation(s)
- Ádrya Vanessa Lira Costa
- Laboratory of Plant Cognition and Electrophysiology, Department of Botany, Institute of Biology, Federal University of Pelotas, Capão do Leão CEP 96160-000, Rio Grande do Sul, Brazil
| | - Thiago Francisco de Carvalho Oliveira
- Laboratory of Plant Cognition and Electrophysiology, Department of Botany, Institute of Biology, Federal University of Pelotas, Capão do Leão CEP 96160-000, Rio Grande do Sul, Brazil
| | - Douglas Antônio Posso
- Laboratory of Plant Cognition and Electrophysiology, Department of Botany, Institute of Biology, Federal University of Pelotas, Capão do Leão CEP 96160-000, Rio Grande do Sul, Brazil
| | - Gabriela Niemeyer Reissig
- Laboratory of Plant Cognition and Electrophysiology, Department of Botany, Institute of Biology, Federal University of Pelotas, Capão do Leão CEP 96160-000, Rio Grande do Sul, Brazil
| | | | - Willian Silva Barros
- Laboratory of Plant Cognition and Electrophysiology, Department of Botany, Institute of Biology, Federal University of Pelotas, Capão do Leão CEP 96160-000, Rio Grande do Sul, Brazil
| | - Gustavo Maia Souza
- Laboratory of Plant Cognition and Electrophysiology, Department of Botany, Institute of Biology, Federal University of Pelotas, Capão do Leão CEP 96160-000, Rio Grande do Sul, Brazil
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9
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Lintilhac PM. Stochasticity and the limits of molecular signaling in plant development. Front Plant Sci 2022; 13:999304. [PMID: 36340340 PMCID: PMC9627605 DOI: 10.3389/fpls.2022.999304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Understanding plant development is in part a theoretical endeavor that can only succeed if it is based upon a correctly contrived axiomatic framework. Here I revisit some of the basic assumptions that frame our understanding of plant development and suggest that we consider an alternative informational ecosystem that more faithfully reflects the physical and architectural realities of plant tissue and organ growth. I discuss molecular signaling as a stochastic process and propose that the iterative and architectural nature of plant growth is more usefully represented by deterministic models based upon structural, surficial, and stress-mechanical information networks that come into play at the trans-cellular level.
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10
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Hou S, Huang Y. THESEUS1 activation by stress: isomerization and peptide perception? Trends Plant Sci 2022; 27:831-833. [PMID: 35660342 DOI: 10.1016/j.tplants.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/25/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Plant cell-wall perturbation upon environmental stress triggers adaptive cellular responses mediated by plasma membrane-resident sensors. We discuss a recent study by Bacete et al. showing that THESEUS1 (THE1) regulates plant cell adaptive responses to cell-wall disruption and update the working model for THE1 activation.
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Affiliation(s)
- Shuguo Hou
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, Shandong 250101, PR China.
| | - Yanyan Huang
- State Key Laboratory of Crop Gene Exploration and Utilization, Southwest China Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China
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11
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Hernandez-Santana V, Perez-Arcoiza A, Gomez-Jimenez MC, Diaz-Espejo A. Disentangling the link between leaf photosynthesis and turgor in fruit growth. Plant J 2021; 107:1788-1801. [PMID: 34250661 DOI: 10.1111/tpj.15418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/25/2021] [Accepted: 07/08/2021] [Indexed: 05/24/2023]
Abstract
Despite the importance of understanding plant growth, the mechanisms underlying how plant and fruit growth declines during drought remain poorly understood. Specifically, it remains unresolved whether carbon or water factors are responsible for limiting growth as drought progresses. We examine questions regarding the relative importance of water and carbon to fruit growth depending on the water deficit level and the fruit growth stage by measuring fruit diameter, leaf photosynthesis, and a proxy of cell turgor in olive (Olea europaea). Flow cytometry was also applied to determine the fruit cell division stage. We found that photosynthesis and turgor were related to fruit growth; specifically, the relative importance of photosynthesis was higher during periods of more intense cell division, while turgor had higher relative importance in periods where cell division comes close to ceasing and fruit growth is dependent mainly on cell expansion. This pattern was found regardless of the water deficit level, although turgor and growth ceased at more similar values of leaf water potential than photosynthesis. Cell division occurred even when fruit growth seemed to stop under water deficit conditions, which likely helped fruits to grow disproportionately when trees were hydrated again, compensating for periods with low turgor. As a result, the final fruit size was not severely penalized. We conclude that carbon and water processes are able to explain fruit growth, with importance placed on the combination of cell division and expansion. However, the major limitation to growth is turgor, which adds evidence to the sink limitation hypothesis.
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Affiliation(s)
- Virginia Hernandez-Santana
- Irrigation and Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda. Reina Mercedes, 41012, Seville, Spain
- Laboratory of Plant Molecular Ecophysiology, Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda. Reina Mercedes, 41012, Seville, Spain
| | - Adrián Perez-Arcoiza
- Irrigation and Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda. Reina Mercedes, 41012, Seville, Spain
| | - Maria C Gomez-Jimenez
- Plant Physiology, Faculty of Science, University of Extremadura, Avda de Elvas s/n, 06006, Badajoz, Spain
| | - Antonio Diaz-Espejo
- Irrigation and Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda. Reina Mercedes, 41012, Seville, Spain
- Laboratory of Plant Molecular Ecophysiology, Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda. Reina Mercedes, 41012, Seville, Spain
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12
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Wong F, Wilson S, Helbig R, Hegde S, Aftenieva O, Zheng H, Liu C, Pilizota T, Garner EC, Amir A, Renner LD. Understanding Beta-Lactam-Induced Lysis at the Single-Cell Level. Front Microbiol 2021; 12:712007. [PMID: 34421870 PMCID: PMC8372035 DOI: 10.3389/fmicb.2021.712007] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 06/30/2021] [Indexed: 12/04/2022] Open
Abstract
Mechanical rupture, or lysis, of the cytoplasmic membrane is a common cell death pathway in bacteria occurring in response to β-lactam antibiotics. A better understanding of the cellular design principles governing the susceptibility and response of individual cells to lysis could indicate methods of potentiating β-lactam antibiotics and clarify relevant aspects of cellular physiology. Here, we take a single-cell approach to bacterial cell lysis to examine three cellular features—turgor pressure, mechanosensitive channels, and cell shape changes—that are expected to modulate lysis. We develop a mechanical model of bacterial cell lysis and experimentally analyze the dynamics of lysis in hundreds of single Escherichia coli cells. We find that turgor pressure is the only factor, of these three cellular features, which robustly modulates lysis. We show that mechanosensitive channels do not modulate lysis due to insufficiently fast solute outflow, and that cell shape changes result in more severe cellular lesions but do not influence the dynamics of lysis. These results inform a single-cell view of bacterial cell lysis and underscore approaches of combatting antibiotic tolerance to β-lactams aimed at targeting cellular turgor.
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Affiliation(s)
- Felix Wong
- Department of Biological Engineering, Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, United States.,John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
| | - Sean Wilson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States.,Center for Systems Biology, Harvard University, Cambridge, MA, United States
| | - Ralf Helbig
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, Dresden, Germany
| | - Smitha Hegde
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Olha Aftenieva
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, Dresden, Germany
| | - Hai Zheng
- CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Chenli Liu
- CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Teuta Pilizota
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States.,Center for Systems Biology, Harvard University, Cambridge, MA, United States
| | - Ariel Amir
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
| | - Lars D Renner
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, Dresden, Germany
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13
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Oldewurtel ER, Kitahara Y, van Teeffelen S. Robust surface-to-mass coupling and turgor-dependent cell width determine bacterial dry-mass density. Proc Natl Acad Sci U S A 2021; 118:e2021416118. [PMID: 34341116 DOI: 10.1073/pnas.2021416118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Intracellular biomass density is an important variable for cellular physiology. It defines the crowded state of the cytoplasm and thus influences macromolecular interactions and transport. To control density during growth, bacteria must expand their cell volumes in synchrony with biomass. The regulation of volume growth and biomass density remain fundamentally not understood—in bacteria or any other organism. Using advanced microscopy, we demonstrate that cells control dry-mass density indirectly through two independent processes. First, cells expand surface area, rather than volume, in proportion with biomass growth. Second, cell width is controlled independently, with an important influence of turgor pressure. Our findings overturn a long-standing paradigm of mass-density constancy in bacteria and reveal fundamental determinants of dry-mass density and shape. During growth, cells must expand their cell volumes in coordination with biomass to control the level of cytoplasmic macromolecular crowding. Dry-mass density, the average ratio of dry mass to volume, is roughly constant between different nutrient conditions in bacteria, but it remains unknown whether cells maintain dry-mass density constant at the single-cell level and during nonsteady conditions. Furthermore, the regulation of dry-mass density is fundamentally not understood in any organism. Using quantitative phase microscopy and an advanced image-analysis pipeline, we measured absolute single-cell mass and shape of the model organisms Escherichia coli and Caulobacter crescentus with improved precision and accuracy. We found that cells control dry-mass density indirectly by expanding their surface, rather than volume, in direct proportion to biomass growth—according to an empirical surface growth law. At the same time, cell width is controlled independently. Therefore, cellular dry-mass density varies systematically with cell shape, both during the cell cycle or after nutrient shifts, while the surface-to-mass ratio remains nearly constant on the generation time scale. Transient deviations from constancy during nutrient shifts can be reconciled with turgor-pressure variations and the resulting elastic changes in surface area. Finally, we find that plastic changes of cell width after nutrient shifts are likely driven by turgor variations, demonstrating an important regulatory role of mechanical forces for width regulation. In conclusion, turgor-dependent cell width and a slowly varying surface-to-mass coupling constant are the independent variables that determine dry-mass density.
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Erickson HP. How Teichoic Acids Could Support a Periplasm in Gram-Positive Bacteria, and Let Cell Division Cheat Turgor Pressure. Front Microbiol 2021; 12:664704. [PMID: 34040598 PMCID: PMC8141598 DOI: 10.3389/fmicb.2021.664704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/06/2021] [Indexed: 12/17/2022] Open
Abstract
The cytoplasm of bacteria is maintained at a higher osmolality than the growth medium, which generates a turgor pressure. The cell membrane (CM) cannot support a large turgor, so there are two possibilities for transferring the pressure to the peptidoglycan cell wall (PGW): (1) the CM could be pressed directly against the PGW, or (2) the CM could be separated from the PGW by a periplasmic space that is isoosmotic with the cytoplasm. There is strong evidence for gram-negative bacteria that a periplasm exists and is isoosmotic with the cytoplasm. No comparable studies have been done for gram-positive bacteria. Here I suggest that a periplasmic space is probably essential in order for the periplasmic proteins to function, including especially the PBPs that remodel the peptidoglycan wall. I then present a semi-quantitative analysis of how teichoic acids could support a periplasm that is isoosmotic with the cytoplasm. The fixed anionic charge density of teichoic acids in the periplasm is ∼0.5 M, which would bring in ∼0.5 M Na+ neutralizing ions. This approximately balances the excess osmolality of the cytoplasm that would produce a turgor pressure of 19 atm. The 0.5 M fixed charge density is similar to that of proteoglycans in articular cartilage, suggesting a comparability ability to support pressure. An isoosmotic periplasm would be especially important for cell division, since it would allow CM constriction and PGW synthesis to avoid turgor pressure.
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Affiliation(s)
- Harold P Erickson
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
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15
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Coussement JR, Villers SLY, Nelissen H, Inzé D, Steppe K. Turgor-time controls grass leaf elongation rate and duration under drought stress. Plant Cell Environ 2021; 44:1361-1378. [PMID: 33373049 DOI: 10.1111/pce.13989] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/17/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
The process of leaf elongation in grasses is characterized by the creation and transformation of distinct cell zones. The prevailing turgor pressure within these cells is one of the key drivers for the rate at which these cells divide, expand and differentiate, processes that are heavily impacted by drought stress. In this article, a turgor-driven growth model for grass leaf elongation is presented, which combines mechanistic growth from the basis of turgor pressure with the ontogeny of the leaf. Drought-induced reductions in leaf turgor pressure result in a simultaneous inhibition of both cell expansion and differentiation, lowering elongation rate but increasing elongation duration due to the slower transitioning of cells from the dividing and elongating zone to mature cells. Leaf elongation is, therefore, governed by the magnitude of, and time spent under, growth-enabling turgor pressure, a metric which we introduce as turgor-time. Turgor-time is able to normalize growth patterns in terms of varying water availability, similar to how thermal time is used to do so under varying temperatures. Moreover, additional inclusion of temperature dependencies within our model pioneers a novel concept enabling the general expression of growth regardless of water availability or temperature.
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Affiliation(s)
- Jonas R Coussement
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Selwyn L Y Villers
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Hilde Nelissen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Dirk Inzé
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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16
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Sakurai G, Miklavcic SJ. On the Efficacy of Water Transport in Leaves. A Coupled Xylem-Phloem Model of Water and Solute Transport. Front Plant Sci 2021; 12:615457. [PMID: 33613602 PMCID: PMC7889512 DOI: 10.3389/fpls.2021.615457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/05/2020] [Indexed: 06/12/2023]
Abstract
In this paper, we present and use a coupled xylem/phloem mathematical model of passive water and solute transport through a reticulated vascular system of an angiosperm leaf. We evaluate the effect of leaf width-to-length proportion and orientation of second-order veins on the indexes of water transport into the leaves and sucrose transport from the leaves. We found that the most important factor affecting the steady-state pattern of hydraulic pressure distribution in the xylem and solute concentration in the phloem was leaf shape: narrower/longer leaves are less efficient in convecting xylem water and phloem solutes than wider/shorter leaves under all conditions studied. The degree of efficiency of transport is greatly influenced by the orientation of second-order veins relative to the main vein for all leaf proportions considered; the dependence is non-monotonic with efficiency maximized when the angle is approximately 45° to the main vein, although the angle of peak efficiency depends on other conditions. The sensitivity of transport efficiency to vein orientation increases with increasing vein conductivity. The vein angle at which efficiency is maximum tended to be smaller (relative to the main vein direction) in narrower leaves. The results may help to explain, or at least contribute to our understanding of, the evolution of parallel vein systems in monocot leaves.
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Affiliation(s)
- Gen Sakurai
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Stanley J. Miklavcic
- Phenomics and Bioinformatics Research Centre, University of South Australia, Mawson Lakes, SA, Australia
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17
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Marino G, Scalisi A, Guzmán-Delgado P, Caruso T, Marra FP, Lo Bianco R. Detecting Mild Water Stress in Olive with Multiple Plant-Based Continuous Sensors. Plants (Basel) 2021; 10:131. [PMID: 33440632 PMCID: PMC7827840 DOI: 10.3390/plants10010131] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/31/2020] [Accepted: 01/08/2021] [Indexed: 02/07/2023]
Abstract
A comprehensive characterization of water stress is needed for the development of automated irrigation protocols aiming to increase olive orchard environmental and economical sustainability. The main aim of this study is to determine whether a combination of continuous leaf turgor, fruit growth, and sap flow responses improves the detection of mild water stress in two olive cultivars characterized by different responses to water stress. The sensitivity of the tested indicators to mild stress depended on the main mechanisms that each cultivar uses to cope with water deficit. One cultivar showed pronounced day to day changes in leaf turgor and fruit relative growth rate in response to water withholding. The other cultivar reduced daily sap flows and showed a pronounced tendency to reach very low values of leaf turgor. Based on these responses, the sensitivity of the selected indicators is discussed in relation to drought response mechanisms, such as stomatal closure, osmotic adjustment, and tissue elasticity. The analysis of the daily dynamics of the monitored parameters highlights the limitation of using non-continuous measurements in drought stress studies, suggesting that the time of the day when data is collected has a great influence on the results and consequent interpretations, particularly when different genotypes are compared. Overall, the results highlight the need to tailor plant-based water management protocols on genotype-specific physiological responses to water deficit and encourage the use of combinations of plant-based continuously monitoring sensors to establish a solid base for irrigation management.
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Affiliation(s)
- Giulia Marino
- Department of Plant Sciences, University of California, Davis, CA 95616, USA;
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, 90133 Palermo, Italy; (A.S.); (T.C.); (F.P.M.)
| | - Alessio Scalisi
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, 90133 Palermo, Italy; (A.S.); (T.C.); (F.P.M.)
- Agriculture Victoria, Department of Jobs, Precincts and Regions, Tatura, VIC 3616, Australia
| | | | - Tiziano Caruso
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, 90133 Palermo, Italy; (A.S.); (T.C.); (F.P.M.)
| | - Francesco Paolo Marra
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, 90133 Palermo, Italy; (A.S.); (T.C.); (F.P.M.)
| | - Riccardo Lo Bianco
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, 90133 Palermo, Italy; (A.S.); (T.C.); (F.P.M.)
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18
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Saikia E, Läubli NF, Burri JT, Rüggeberg M, Vogler H, Burgert I, Herrmann HJ, Nelson BJ, Grossniklaus U, Wittel FK. Kinematics Governing Mechanotransduction in the Sensory Hair of the Venus flytrap. Int J Mol Sci 2020; 22:E280. [PMID: 33396579 DOI: 10.3390/ijms22010280] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/14/2022] Open
Abstract
Insects fall prey to the Venus flytrap (Dionaea muscipula) when they touch the sensory hairs located on the flytrap lobes, causing sudden trap closure. The mechanical stimulus imparted by the touch produces an electrical response in the sensory cells of the trigger hair. These cells are found in a constriction near the hair base, where a notch appears around the hair’s periphery. There are mechanosensitive ion channels (MSCs) in the sensory cells that open due to a change in membrane tension; however, the kinematics behind this process is unclear. In this study, we investigate how the stimulus acts on the sensory cells by building a multi-scale hair model, using morphometric data obtained from μ-CT scans. We simulated a single-touch stimulus and evaluated the resulting cell wall stretch. Interestingly, the model showed that high stretch values are diverted away from the notch periphery and, instead, localized in the interior regions of the cell wall. We repeated our simulations for different cell shape variants to elucidate how the morphology influences the location of these high-stretch regions. Our results suggest that there is likely a higher mechanotransduction activity in these ’hotspots’, which may provide new insights into the arrangement and functioning of MSCs in the flytrap. Dataset: 10.3929/ethz-b-000448954
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Kunieda T, Kishida K, Kawamura J, Demura T. Influence of osmotic condition on secondary cell wall formation of xylem vessel cells induced by the master transcription factor VND7. Plant Biotechnol (Tokyo) 2020; 37:465-469. [PMID: 33850435 PMCID: PMC8034666 DOI: 10.5511/plantbiotechnology.20.1127a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Xylem vessels, which conduct water from roots to aboveground tissues in vascular plants, are stiffened by secondary cell walls (SCWs). Protoxylem vessel cells deposit cellulose, hemicellulose, and lignin as SCW components in helical and/or annular patterns. The mechanisms underlying SCW patterning in the protoxylem vessel cells are not fully understood, although VASCULAR-RERATED NAC-DOMAIN 7 (VND7) has been identified as a master transcription factor in protoxylem vessel cell differentiation in Arabidopsis thaliana. Here, we investigated deposition patterns of SCWs throughout the tissues of Arabidopsis seedlings using an inducible transdifferentiation system that utilizes a chimeric protein in which VND7 is fused with the activation domain of VP16 and the glucocorticoid receptor (GR) (VND7-VP16-GR). In slender- and cylinder-shaped cells, such as petiole and hypocotyl cells, SCWs that were ectopically induced by the VND7-VP16-GR system were deposited linearly, resulting in helical and annular patterns similar to the endogenous patterns in protoxylem vessel cells. By contrast, concentrated linear SCW deposition was associated with unevenness on the surface of pavement cells in cotyledon leaf blades, suggesting the involvement of cell morphology in SCW patterning. When we exposed the seedlings to hypertonic conditions that induced plasmolysis, we observed aberrant deposition patterns in SCW formation. Because the turgor pressure becomes zero at the point when cells reach limiting plasmolysis, this result implies that proper turgor pressure is required for normal SCW patterning. Taken together, our results suggest that the deposition pattern of SCWs is affected by mechanical stimuli that are related to cell morphogenesis and turgor pressure.
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Affiliation(s)
- Tadashi Kunieda
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Keisuke Kishida
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Jumpei Kawamura
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Taku Demura
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- E-mail: Tel: +81-743-72-5460 Fax: +81-743-72-5469
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20
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Roumeli E, Ginsberg L, McDonald R, Spigolon G, Hendrickx R, Ohtani M, Demura T, Ravichandran G, Daraio C. Structure and Biomechanics during Xylem Vessel Transdifferentiation in Arabidopsis thaliana. Plants (Basel) 2020; 9:E1715. [PMID: 33291397 DOI: 10.3390/plants9121715] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/30/2020] [Accepted: 12/03/2020] [Indexed: 01/04/2023]
Abstract
Individual plant cells are the building blocks for all plantae and artificially constructed plant biomaterials, like biocomposites. Secondary cell walls (SCWs) are a key component for mediating mechanical strength and stiffness in both living vascular plants and biocomposite materials. In this paper, we study the structure and biomechanics of cultured plant cells during the cellular developmental stages associated with SCW formation. We use a model culture system that induces transdifferentiation of Arabidopsis thaliana cells to xylem vessel elements, upon treatment with dexamethasone (DEX). We group the transdifferentiation process into three distinct stages, based on morphological observations of the cell walls. The first stage includes cells with only a primary cell wall (PCW), the second covers cells that have formed a SCW, and the third stage includes cells with a ruptured tonoplast and partially or fully degraded PCW. We adopt a multi-scale approach to study the mechanical properties of cells in these three stages. We perform large-scale indentations with a micro-compression system in three different osmotic conditions. Atomic force microscopy (AFM) nanoscale indentations in water allow us to isolate the cell wall response. We propose a spring-based model to deconvolve the competing stiffness contributions from turgor pressure, PCW, SCW and cytoplasm in the stiffness of differentiating cells. Prior to triggering differentiation, cells in hypotonic pressure conditions are significantly stiffer than cells in isotonic or hypertonic conditions, highlighting the dominant role of turgor pressure. Plasmolyzed cells with a SCW reach similar levels of stiffness as cells with maximum turgor pressure. The stiffness of the PCW in all of these conditions is lower than the stiffness of the fully-formed SCW. Our results provide the first experimental characterization of the mechanics of SCW formation at single cell level.
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21
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Goeschl JD, Han L. A Proposed Drought Response Equation Added to the Münch-Horwitz Theory of Phloem Transport. Front Plant Sci 2020; 11:505153. [PMID: 33250905 PMCID: PMC7672028 DOI: 10.3389/fpls.2020.505153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 09/14/2020] [Indexed: 06/12/2023]
Abstract
Theoretical and experimental evidence for an effect of sieve tube turgor pressure on the mechanisms of phloem unloading near the root tips during moderate levels of drought stress is reviewed. An additional, simplified equation is proposed relating decreased turgor pressure to decreased rate kinetics of membrane bound transporters. The effect of such a mechanism would be to decrease phloem transport speed, but increase concentration and pressure, and thus prevent or delay negative pressure in the phloem. Experimental evidence shows this mechanism precedes and exceeds a reduction in stomatal conductance.
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Affiliation(s)
- John D. Goeschl
- Department of Industrial and Systems Engineering, College of Engineering, Texas A&M University, College Station, TX, United States
| | - Lifeng Han
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, United States
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22
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Zhang D, Zhang B. Pectin Drives Cell Wall Morphogenesis without Turgor Pressure. Trends Plant Sci 2020; 25:719-722. [PMID: 32513584 DOI: 10.1016/j.tplants.2020.05.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 05/21/2023]
Abstract
How the plant cell wall expands and forms shapes is a long-standing mystery. Traditional thought is that turgor pressure drives these processes. However, a recent study by Haas and colleagues shows for the first time that the expansion of pectin homogalacturonan nanofilaments drives morphogenesis without turgor pressure in plant epidermal cells.
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Affiliation(s)
- Dangquan Zhang
- Henan Province Engineering Research Center for Forest Biomass Value-Added Products, College of Forestry, Henan Agricultural University, Zhengzhou, Henan 450002, China.
| | - Baohong Zhang
- Department of Biology, East Carolina University, Greenville, NC 27858, USA.
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23
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Hagihara T, Toyota M. Mechanical Signaling in the Sensitive Plant Mimosa pudica L. Plants (Basel) 2020; 9:E587. [PMID: 32375332 PMCID: PMC7284940 DOI: 10.3390/plants9050587] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/01/2020] [Accepted: 05/02/2020] [Indexed: 01/10/2023]
Abstract
As sessile organisms, plants do not possess the nerves and muscles that facilitate movement in most animals. However, several plant species can move quickly in response to various stimuli (e.g., touch). One such plant species, Mimosa pudica L., possesses the motor organ pulvinus at the junction of the leaflet-rachilla, rachilla-petiole, and petiole-stem, and upon mechanical stimulation, this organ immediately closes the leaflets and moves the petiole. Previous electrophysiological studies have demonstrated that a long-distance and rapid electrical signal propagates through M. pudica in response to mechanical stimulation. Furthermore, the spatial and temporal patterns of the action potential in the pulvinar motor cells were found to be closely correlated with rapid movements. In this review, we summarize findings from past research and discuss the mechanisms underlying long-distance signal transduction in M. pudica. We also propose a model in which the action potential, followed by water flux (i.e., a loss of turgor pressure) in the pulvinar motor cells is a critical step to enable rapid movement.
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Affiliation(s)
- Takuma Hagihara
- Department of Biochemistry and Molecular Biology, Saitama University, Saitama 338-8570, Japan;
| | - Masatsugu Toyota
- Department of Biochemistry and Molecular Biology, Saitama University, Saitama 338-8570, Japan;
- Department of Botany, University of Wisconsin, Madison, WI 53706, USA
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Scalisi A, Marino G, Marra FP, Caruso T, Lo Bianco R. A Cultivar-Sensitive Approach for the Continuous Monitoring of Olive ( Olea europaea L.) Tree Water Status by Fruit and Leaf Sensing. Front Plant Sci 2020; 11:340. [PMID: 32265975 PMCID: PMC7108149 DOI: 10.3389/fpls.2020.00340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/06/2020] [Indexed: 06/11/2023]
Abstract
Sustainable irrigation is crucial to reduce water use and management costs in modern orchard systems. Continuous plant-based sensing is an innovative approach for the continuous monitoring of plant water status. Olive (Olea europaea L.) genotypes can respond to drought using different leaf and fruit physiological and morphological mechanisms. This study aimed to identify whether fruit and leaf water dynamics of two different olive cultivars were differently affected by water deficit and their response to changes of midday stem water potential (Ψstem), the most common indicator of plant water status. Plant water status indicators such as leaf stomatal conductance (gs) and Ψstem were measured in the Sicilian olive cultivars Nocellara del Belice (NB) and Olivo di Mandanici (MN), in stage II and III of fruit development. Fruit gauges and leaf patch clamp pressure probes were mounted on trees and their raw data were converted in relative rates of fruit diameter change (RRfruit) and leaf pressure change (RRleaf), sensitive indicators of tissue water exchanges. The analysis of diel, diurnal and nocturnal fluctuations of RRfruit and RRleaf highlighted differences, often opposite, between the two cultivars under water deficit. A combination of statistical parameters extrapolated from RRfruit and RRleaf diurnal and nocturnal curves were successfully used to obtain significant multiple linear models for the estimation of midday Ψstem. Fruit and leaf water exchanges suggest that olive cultivar can either privilege fruit or leaf water status, with MN likely preserving leaf water status and NB increasing fruit tissue elasticity under severe water deficit. The results highlight the advantages of the integration of fruit and leaf water dynamics to estimate plant water status and the need for genotype-specific models in olive.
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Affiliation(s)
- Alessio Scalisi
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, Palermo, Italy
- Agriculture Victoria, Department of Jobs, Precincts and Regions, Tatura, VIC, Australia
| | - Giulia Marino
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, Palermo, Italy
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
| | - Francesco Paolo Marra
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, Palermo, Italy
| | - Tiziano Caruso
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, Palermo, Italy
| | - Riccardo Lo Bianco
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, Palermo, Italy
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25
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Long Y, Cheddadi I, Mosca G, Mirabet V, Dumond M, Kiss A, Traas J, Godin C, Boudaoud A. Cellular Heterogeneity in Pressure and Growth Emerges from Tissue Topology and Geometry. Curr Biol 2020; 30:1504-1516.e8. [PMID: 32169211 DOI: 10.1016/j.cub.2020.02.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 01/13/2020] [Accepted: 02/11/2020] [Indexed: 01/22/2023]
Abstract
Cell-to-cell heterogeneity prevails in many systems, as exemplified by cell growth, although the origin and function of such heterogeneity are often unclear. In plants, growth is physically controlled by cell wall mechanics and cell hydrostatic pressure, alias turgor pressure. Whereas cell wall heterogeneity has received extensive attention, the spatial variation of turgor pressure is often overlooked. Here, combining atomic force microscopy and a physical model of pressurized cells, we show that turgor pressure is heterogeneous in the Arabidopsis shoot apical meristem, a population of stem cells that generates all plant aerial organs. In contrast with cell wall mechanical properties that appear to vary stochastically between neighboring cells, turgor pressure anticorrelates with cell size and cell neighbor number (local topology), in agreement with the prediction by our model of tissue expansion, which couples cell wall mechanics and tissue hydraulics. Additionally, our model predicts two types of correlations between pressure and cellular growth rate, where high pressure may lead to faster- or slower-than-average growth, depending on cell wall extensibility, yield threshold, osmotic pressure, and hydraulic conductivity. The meristem exhibits one of these two regimes, depending on conditions, suggesting that, in this tissue, water conductivity may contribute to growth control. Our results unravel cell pressure as a source of patterned heterogeneity and illustrate links between local topology, cell mechanical state, and cell growth, with potential roles in tissue homeostasis.
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Affiliation(s)
- Yuchen Long
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69342 Lyon, France.
| | - Ibrahim Cheddadi
- Université Grenoble Alpes, CNRS, Grenoble INP, TIMC-IMAG, 38000 Grenoble, France
| | - Gabriella Mosca
- Department of Plant and Microbial Biology, University of Zürich, Zollikerstrasse 107, 8008 Zürich, Switzerland
| | - Vincent Mirabet
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69342 Lyon, France; Lycée A. et L. Lumière, 69372 Lyon Cedex 08, France
| | - Mathilde Dumond
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69342 Lyon, France
| | - Annamaria Kiss
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69342 Lyon, France
| | - Jan Traas
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69342 Lyon, France
| | - Christophe Godin
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69342 Lyon, France
| | - Arezki Boudaoud
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, 69342 Lyon, France.
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Hernández-Hernández V, Benítez M, Boudaoud A. Interplay between turgor pressure and plasmodesmata during plant development. J Exp Bot 2020; 71:768-777. [PMID: 31563945 DOI: 10.1093/jxb/erz434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/09/2019] [Indexed: 06/10/2023]
Abstract
Plasmodesmata traverse cell walls, generating connections between neighboring cells. They allow intercellular movement of molecules such as transcription factors, hormones, and sugars, and thus create a symplasmic continuity within a tissue. One important factor that determines plasmodesmal permeability is their aperture, which is regulated during developmental and physiological processes. Regulation of aperture has been shown to affect developmental events such as vascular differentiation in the root, initiation of lateral roots, or transition to flowering. Extensive research has unraveled molecular factors involved in the regulation of plasmodesmal permeability. Nevertheless, many plant developmental processes appear to involve feedbacks mediated by mechanical forces, raising the question of whether mechanical forces and plasmodesmal permeability affect each other. Here, we review experimental data on how one of these forces, turgor pressure, and plasmodesmal permeability may mutually influence each other during plant development, and we discuss the questions raised by these data. Addressing such questions will improve our knowledge of how cellular patterns emerge during development, shedding light on the evolution of complex multicellular plants.
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Affiliation(s)
- Valeria Hernández-Hernández
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon, France
| | - Mariana Benítez
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología & Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Arezki Boudaoud
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon, France
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27
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van Wyk AS, Prinsloo G. Challenging current interpretation of sunflower movements. J Exp Bot 2019; 70:6049-6056. [PMID: 31504705 DOI: 10.1093/jxb/erz381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 08/14/2019] [Indexed: 06/10/2023]
Abstract
In the literature, Helianthus annuus L. (sunflower) movements are generally described as heliotropic. It is generally believed that the leaves and flowers of the growing H. annuus plant track the sun as the sun moves across the sky from east to west. This paper, however, challenges current interpretation regarding H. annuus movements, as the literature generally excludes the rotation of the earth around its own axis, gravity, and the possible role of gravitation. The general exclusion of the earth's rotation in the literature may also have resulted in flawed research design in studies conducted on H. annuus movements, which in turn may have directed researchers towards the misinterpretation of results. This paper aims to include the possible role of the Earth's rotation, gravity, and gravitation when describing H. annuus movements and to provide possible alternative explanations for the results achieved by researchers. This paper further includes concepts and examples relevant to plant movements, such as the rhythms often associated with plant movements, the physiology of plant movements, referring to turgor pressure as the main force behind plant movements, and plant rhythmic clocks and their characteristics, in order to explain the alternative views and to relate them to H. annuus movements.
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Affiliation(s)
- Anne S van Wyk
- Department of Environmental Sciences, University of South Africa, Florida campus, Florida, South Africa
| | - Gerhard Prinsloo
- Department of Agriculture and Animal Health, University of South Africa, Florida campus, Florida, South Africa
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28
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Echevin E, Le Gloanec C, Skowrońska N, Routier-Kierzkowska AL, Burian A, Kierzkowski D. Growth and biomechanics of shoot organs. J Exp Bot 2019; 70:3573-3585. [PMID: 31037307 DOI: 10.1093/jxb/erz205] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
Plant organs arise through complex interactions between biological and physical factors that control morphogenesis. While there has been tremendous progress in the understanding of the genetics behind development, we know much less about how mechanical forces control growth in plants. In recent years, new multidisciplinary research combining genetics, live-imaging, physics, and computational modeling has begun to fill this gap by revealing the crucial role of biomechanics in the establishment of plant organs. In this review, we provide an overview of our current understanding of growth during initiation, patterning, and expansion of shoot lateral organs. We discuss how growth is controlled by physical forces, and how mechanical stresses generated during growth can control morphogenesis at the level of both cells and tissues. Understanding the mechanical basis of growth and morphogenesis in plants is in its early days, and many puzzling facts are yet to be deciphered.
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Affiliation(s)
- Emilie Echevin
- Institut de Recherche en Biologie Végétale, Department of Biological Sciences, University of Montreal, Montréal, QC, Canada
| | - Constance Le Gloanec
- Institut de Recherche en Biologie Végétale, Department of Biological Sciences, University of Montreal, Montréal, QC, Canada
| | - Nikolina Skowrońska
- Department of Biophysics and Morphogenesis of Plants, University of Silesia, Jagiellońska, Katowice, Poland
| | - Anne-Lise Routier-Kierzkowska
- Institut de Recherche en Biologie Végétale, Department of Biological Sciences, University of Montreal, Montréal, QC, Canada
| | - Agata Burian
- Department of Biophysics and Morphogenesis of Plants, University of Silesia, Jagiellońska, Katowice, Poland
| | - Daniel Kierzkowski
- Institut de Recherche en Biologie Végétale, Department of Biological Sciences, University of Montreal, Montréal, QC, Canada
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29
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Yi H, Chen Y, Wang JZ, Puri VM, Anderson CT. The stomatal flexoskeleton: how the biomechanics of guard cell walls animate an elastic pressure vessel. J Exp Bot 2019; 70:3561-3572. [PMID: 30977824 DOI: 10.1093/jxb/erz178] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 04/08/2019] [Indexed: 06/09/2023]
Abstract
In plants, stomatal guard cells are one of the most dynamic cell types, rapidly changing their shape and size in response to environmental and intrinsic signals to control gas exchange at the plant surface. Quantitative and systematic knowledge of the biomechanical underpinnings of stomatal dynamics will enable strategies to optimize stomatal responsiveness and improve plant productivity by enhancing the efficiency of photosynthesis and water use. Recent developments in microscopy, mechanical measurements, and computational modeling have revealed new insights into the biomechanics of stomatal regulation and the genetic, biochemical, and structural origins of how plants achieve rapid and reliable stomatal function by tuning the mechanical properties of their guard cell walls. This review compares historical and recent experimental and modeling studies of the biomechanics of stomatal complexes, highlighting commonalities and contrasts between older and newer studies. Key gaps in our understanding of stomatal functionality are also presented, along with assessments of potential methods that could bridge those gaps.
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Affiliation(s)
- Hojae Yi
- Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Yintong Chen
- Department of Biology and Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA, USA
| | - James Z Wang
- College of Information Sciences and Technology The Pennsylvania State University, University Park, PA, USA
| | - Virendra M Puri
- Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Charles T Anderson
- Department of Biology and Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA, USA
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30
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Lee JW, Kim GH. Red And far-red regulation of filament movement correlates with the expression of phytochrome and FHY1 genes in Spirogyra varians (Zygnematales, Streptophyta) 1. J Phycol 2019; 55:688-699. [PMID: 30805922 DOI: 10.1111/jpy.12849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 02/05/2019] [Indexed: 06/09/2023]
Abstract
Spirogyra filaments show unique photomovement that differs in response to blue, red, and far-red light. Phototropins involved in the blue-light movement have been characterized together with downstream signaling components, but the photoreceptors and mechanical effectors of red- and far-red light movement are not yet characterized. The filaments of Spirogyra varians slowly bent and aggregated to form a tangled mass in red light. In far-red light, the filaments unbent, stretched rapidly, and separated from each other. Mannitol and/or sorbitol treatment significantly inhibited this far-red light movement suggesting that turgor pressure is the driving force of this movement. The bending and aggregating movements of filaments in red light were not affected by osmotic change. Three phytochrome homologues isolated from S. varians showed unique phylogenetic characteristics. Two canonical phytochromes, named SvPHY1 and SvPHY2, and a noncanonical phytochrome named SvPHYX2. SvPHY1 is the first PHY1 family phytochrome reported in zygnematalean algae. The gene involved in the transport of phytochromes into the nucleus was characterized, and its expression in response to red and far-red light was measured using quantitative PCR. Our results suggest that the phytochromes and the genes involved in the transport system into the nucleus are well conserved in S. varians.
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Affiliation(s)
- Ji Woong Lee
- Department of Biological Sciences, Kongju National University, Gongju, 32588, Korea
| | - Gwang Hoon Kim
- Department of Biological Sciences, Kongju National University, Gongju, 32588, Korea
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31
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Alvarez MD, Velarde C, Barrios L, Herranz B. Understanding the crispy-crunchy texture of raw red pepper and its change with storage time. J Texture Stud 2019; 51:120-133. [PMID: 31090068 DOI: 10.1111/jtxs.12443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/18/2019] [Accepted: 05/07/2019] [Indexed: 11/29/2022]
Abstract
Red sweet peppers held in cold storage were periodically sampled at 1-week intervals over a 3-weeks period using three-point bending, puncture, cutting, and Volodkevich (coupled with acoustic emission) tests, confocal laser scanning microscopy (CLSM) and other physicochemical measurements. At each sampling, tissue specimens were soaked in mannitol solutions (0.0-0.9M) and puncture test, dimension changes and CLSM were used to identify degrees of turgidity present in osmotically manipulated pepper tissue. Pepper texture became crumbly with increased storage time due to softening and wilting processes. The Young's modulus, derived from the bending test using the single-edge notched bend geometry without notches decreased progressively during cold storage and resulted as the best mechanical parameter for measuring the loss of whole-tissue stiffness by both decreased cell wall stiffness and turgor pressure. Osmotic adjustment indicated that the pepper structure is extremely anisotropic, with the specimen's "average" relative thickness (RT) being the dimension change more affected. Incipient plasmolysis was evident in the highest mannitol concentration (0.9M), therefore, the turgor pressure of nonsoaked tissue could not be inferred. However, significant correlations were found between RT and puncture parameters such as initial slope, initial and final distances, and the number of flesh and skin force peaks, which depended on the dilation or shrinkage caused by the osmotic adjustment. During storage, soaked tissues had lower crunchy texture than nonsoaked, reflecting that cell wall stiffness plays a more significant role in determining pepper crunchiness than cell turgor pressure.
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Affiliation(s)
- María Dolores Alvarez
- Department of Characterisation, Quality, and Safety, Institute of Food Science, Technology and Nutrition (ICTAN-CSIC), Madrid, Spain
| | - Cristina Velarde
- Department of Characterisation, Quality, and Safety, Institute of Food Science, Technology and Nutrition (ICTAN-CSIC), Madrid, Spain
| | - Laura Barrios
- Department of Statistics, Computing Centre (SGAI-CSIC), Madrid, Spain
| | - Beatriz Herranz
- Department of Characterisation, Quality, and Safety, Institute of Food Science, Technology and Nutrition (ICTAN-CSIC), Madrid, Spain
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Zhu J, Génard M, Poni S, Gambetta GA, Vivin P, Vercambre G, Trought MCT, Ollat N, Delrot S, Dai Z. Modelling grape growth in relation to whole-plant carbon and water fluxes. J Exp Bot 2019; 70:2505-2521. [PMID: 30357362 PMCID: PMC6487596 DOI: 10.1093/jxb/ery367] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/16/2018] [Indexed: 05/04/2023]
Abstract
The growth of fleshy fruits is still poorly understood as a result of the complex integration of water and solute fluxes, cell structural properties, and the regulation of whole plant source-sink relationships. To unravel the contribution of these processes to berry growth, a biophysical grape (Vitis vinifera L.) berry growth module was developed and integrated with a whole-plant functional-structural model, and was calibrated on two varieties, Cabernet Sauvignon and Sangiovese. The model captured well the variations in growth and sugar accumulation caused by environmental conditions, changes in leaf-to-fruit ratio, plant water status, and varietal differences, with obvious future application in predicting yield and maturity under a variety of production contexts and regional climates. Our analyses illustrated that grapevines strive to maintain proper ripening by partially compensating for a reduced source-sink ratio, and that under drought an enhanced berry sucrose uptake capacity can reverse berry shrinkage. Sensitivity analysis highlighted the importance of phloem hydraulic conductance, sugar uptake, and surface transpiration on growth, while suggesting that cell wall extensibility and the turgor threshold for cell expansion had minor effects. This study demonstrates that this integrated model is a useful tool in understanding the integration and relative importance of different processes in driving fleshy fruit growth.
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Affiliation(s)
- Junqi Zhu
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, ISVV, Villenave d’Ornon, France
- The New Zealand Institute for Plant and Food Research Limited (PFR) Marlborough, Blenheim, New Zealand
| | - Michel Génard
- INRA, UR 1115 Plantes et Systèmes de Culture Horticoles, Avignon, France
| | - Stefano Poni
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense, Piacenza, Italy
| | - Gregory A Gambetta
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, ISVV, Villenave d’Ornon, France
| | - Philippe Vivin
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, ISVV, Villenave d’Ornon, France
| | - Gilles Vercambre
- INRA, UR 1115 Plantes et Systèmes de Culture Horticoles, Avignon, France
| | - Michael C T Trought
- The New Zealand Institute for Plant and Food Research Limited (PFR) Marlborough, Blenheim, New Zealand
| | - Nathalie Ollat
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, ISVV, Villenave d’Ornon, France
| | - Serge Delrot
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, ISVV, Villenave d’Ornon, France
| | - Zhanwu Dai
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, ISVV, Villenave d’Ornon, France
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Epron D, Dannoura M, Ishida A, Kosugi Y. Estimation of phloem carbon translocation belowground at stand level in a hinoki cypress stand. Tree Physiol 2019; 39:320-331. [PMID: 29474703 DOI: 10.1093/treephys/tpy016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 01/15/2018] [Accepted: 01/27/2018] [Indexed: 06/08/2023]
Abstract
At stand level, carbon translocation in tree stems has to match canopy photosynthesis and carbohydrate requirements to sustain growth and the physiological activities of belowground sinks. This study applied the Hagen-Poiseuille equation to the pressure-flow hypothesis to estimate phloem carbon translocation and evaluate what percentage of canopy photosynthate can be transported belowground in a hinoki cypress (Chamaecyparis obtusa Sieb. et Zucc.) stand. An anatomical study revealed that, in contrast to sieve cell density, conductive phloem thickness and sieve cell hydraulic diameter at 1.3 m in height increased with increasing tree diameter, as did the concentration of soluble sugars in the phloem sap. At tree level, hydraulic conductivity increased by two orders of magnitude from the smallest to the largest trees in the stand, resulting in a stand-level hydraulic conductance of 1.7 × 10-15 m Pa-1 s-1. The osmotic potential of the sap extracted from the inner bark was -0.75 MPa. Assuming that phloem water potential equalled foliage water potential at predawn, the turgor pressure in the phloem at 1.3 m in height was estimated at 0.22 MPa, 0.59 MPa lower than values estimated in the foliage. With this maximal turgor pressure gradient, which would be lower during day-time when foliage water potential drops, the estimated stand-level rate of carbon translocation was 2.0 gC m-2 day-1 (30% of daily gross canopy photosynthesis), at a time of the year when aboveground growth and related respiration is thought to consume a large fraction of photosynthate, at the expense of belowground activity. Despite relying on some assumptions and approximations, this approach, when coupled with measurements of canopy photosynthesis, may further be used to provide qualitative insight into the seasonal dynamics of belowground carbon allocation.
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Affiliation(s)
- Daniel Epron
- Université de Lorraine, INRA, UMR SILVA, Faculté des Sciences et Technologies, Vandœuvre-lès-Nancy, France
- Kyoto University, Laboratory of Ecosystem Production and Dynamics, Graduate School of Global Environmental Studies, Kyoto, Japan
| | - Masako Dannoura
- Kyoto University, Laboratory of Ecosystem Production and Dynamics, Graduate School of Global Environmental Studies, Kyoto, Japan
- Kyoto University, Laboratory of Forest Utilization, Graduate School of Agriculture, Kyoto, Japan
| | - Atsushi Ishida
- Kyoto University, Center for Ecological Research, Otsu, Shiga, Japan
| | - Yoshiko Kosugi
- Kyoto University, Laboratory of Forest Hydrology, Graduate School of Agriculture, Kyoto, Japan
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34
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Lopez-Garrido J, Ojkic N, Khanna K, Wagner FR, Villa E, Endres RG, Pogliano K. Chromosome Translocation Inflates Bacillus Forespores and Impacts Cellular Morphology. Cell 2019; 172:758-770.e14. [PMID: 29425492 DOI: 10.1016/j.cell.2018.01.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 10/16/2017] [Accepted: 01/18/2018] [Indexed: 01/14/2023]
Abstract
The means by which the physicochemical properties of different cellular components together determine bacterial cell shape remain poorly understood. Here, we investigate a programmed cell-shape change during Bacillus subtilis sporulation, when a rod-shaped vegetative cell is transformed to an ovoid spore. Asymmetric cell division generates a bigger mother cell and a smaller, hemispherical forespore. The septum traps the forespore chromosome, which is translocated to the forespore by SpoIIIE. Simultaneously, forespore size increases as it is reshaped into an ovoid. Using genetics, timelapse microscopy, cryo-electron tomography, and mathematical modeling, we demonstrate that forespore growth relies on membrane synthesis and SpoIIIE-mediated chromosome translocation, but not on peptidoglycan or protein synthesis. Our data suggest that the hydrated nucleoid swells and inflates the forespore, displacing ribosomes to the cell periphery, stretching septal peptidoglycan, and reshaping the forespore. Our results illustrate how simple biophysical interactions between core cellular components contribute to cellular morphology.
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Affiliation(s)
- Javier Lopez-Garrido
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nikola Ojkic
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; Centre for Integrative Systems Biology and Bioinformatics, London SW7 2AZ, UK
| | - Kanika Khanna
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Felix R Wagner
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Elizabeth Villa
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Robert G Endres
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; Centre for Integrative Systems Biology and Bioinformatics, London SW7 2AZ, UK.
| | - Kit Pogliano
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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Scalisi A, O’Connell MG, Stefanelli D, Lo Bianco R. Fruit and Leaf Sensing for Continuous Detection of Nectarine Water Status. Front Plant Sci 2019; 10:805. [PMID: 31333685 PMCID: PMC6616271 DOI: 10.3389/fpls.2019.00805] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/04/2019] [Indexed: 05/14/2023]
Abstract
Continuous assessment of plant water status indicators provides the most precise information for irrigation management and automation, as plants represent an interface between soil and atmosphere. This study investigated the relationship of plant water status to continuous fruit diameter (FD) and inverse leaf turgor pressure rates (p p) in nectarine trees [Prunus persica (L.) Batsch] throughout fruit development. The influence of deficit irrigation treatments on stem (Ψ stem) and leaf water potential, leaf relative water content, leaf stomatal conductance, and fruit growth was studied across the stages of double-sigmoidal fruit development in 'September Bright' nectarines. Fruit relative growth rate (RGR) and leaf relative pressure change rate (RPCR) were derived from FD and p p to represent rates of water in- and outflows in the organs, respectively. Continuous RGR and RPCR dynamics were independently and jointly related to plant water status and environmental variables. The independent use of RGR and RPCR yielded significant associations with midday Ψ stem, the most representative index of tree water status in anisohydric species. However, a combination of nocturnal fruit and leaf parameters unveiled an even more significant relationship with Ψ stem, suggesting a changing behavior of fruit and leaf water flows in response to pronounced water deficit. In conclusion, we highlight the suitability of a dual-organ sensing approach for improved prediction of tree water status.
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Affiliation(s)
- Alessio Scalisi
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, Palermo, Italy
- Department of Jobs, Precincts and Regions, Agriculture Victoria, Tatura, VIC, Australia
- *Correspondence: Alessio Scalisi,
| | - Mark Glenn O’Connell
- Department of Jobs, Precincts and Regions, Agriculture Victoria, Tatura, VIC, Australia
| | - Dario Stefanelli
- Department of Jobs, Precincts and Regions, Agriculture Victoria, Tatura, VIC, Australia
| | - Riccardo Lo Bianco
- Department of Agricultural, Food and Forest Sciences (SAAF), University of Palermo, Palermo, Italy
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36
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Dong H, Bai L, Zhang Y, Zhang G, Mao Y, Min L, Xiang F, Qian D, Zhu X, Song CP. Modulation of Guard Cell Turgor and Drought Tolerance by a Peroxisomal Acetate-Malate Shunt. Mol Plant 2018; 11:1278-1291. [PMID: 30130577 DOI: 10.1016/j.molp.2018.07.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 07/13/2018] [Accepted: 07/31/2018] [Indexed: 06/08/2023]
Abstract
In plants, stomatal movements are tightly controlled by changes in cellular turgor pressure. Carbohydrates produced by glycolysis and the tricarboxylic acid cycle play an important role in regulating turgor pressure. Here, we describe an Arabidopsis mutant, bzu1, isolated in a screen for elevated leaf temperature in response to drought stress, which displays smaller stomatal pores and higher drought resistance than wild-type plants. BZU1 encodes a known acetyl-coenzyme A synthetase, ACN1, which acts in the first step of a metabolic pathway converting acetate to malate in peroxisomes. We showed that BZU1/ACN1-mediated acetate-to-malate conversion provides a shunt that plays an important role in osmoregulation of stomatal turgor. We found that the smaller stomatal pores in the bzu1 mutant are a consequence of reduced accumulation of malate, which acts as an osmoticum and/or a signaling molecule in the control of turgor pressure within guard cells, and these results provided new genetic evidence for malate-regulated stomatal movement. Collectively, our results indicate that a peroxisomal BZU1/ACN1-mediated acetate-malate shunt regulates drought resistance by controlling the turgor pressure of guard cells in Arabidopsis.
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Affiliation(s)
- Huan Dong
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China
| | - Ling Bai
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China
| | - Yu Zhang
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China
| | - Guozeng Zhang
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China
| | - Yanqing Mao
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China
| | - Lulu Min
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China
| | - Fuyou Xiang
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China
| | - Dongdong Qian
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China
| | - Xiaohong Zhu
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China
| | - Chun-Peng Song
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng 475001, China.
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37
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Zlinszky A, Barfod A. Short interval overnight laser scanning suggest sub-circadian periodicity of tree turgor. Plant Signal Behav 2018; 13:e1439655. [PMID: 29431575 PMCID: PMC5846560 DOI: 10.1080/15592324.2018.1439655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 02/01/2018] [Indexed: 06/02/2023]
Abstract
A recent study by Zlinszky et al., 1 uses high-resolution terrestrial laser scanning to investigate the variability of overnight movement of leaves and branches in vascular plants. This study finds among others that the investigated plants show periodic movements of around one centimetre in amplitude and 2-6 hour periodicity. Sub-circadian process dynamics of plants were so far not in focus of research, but here we compare the findings with other published cases of short-term periodicity in leaf turgor, sap flow and especially trunk diameter. Several authors have noted overnight variations in these parameters within periods of several hours and in absence of environmental changes with similar dynamics. We revisit the unknown questions of short-term plant movement and make a suggestion for future research.
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Affiliation(s)
- András Zlinszky
- Ecoinformatics and Biodiversity Section, Department of Bioscience, Aarhus University, Aarhus, Denmark
- Balaton Limnological Institute, Centre for Ecological Research, Hungarian Academy of Sciences, Tihany, Hungary
| | - Anders Barfod
- Ecoinformatics and Biodiversity Section, Department of Bioscience, Aarhus University, Aarhus, Denmark
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Zlinszky A, Barfod A. Short interval overnight laser scanning suggests sub-circadian periodicity of tree turgor. Plant Signal Behav 2018; 13:e1441656. [PMID: 29452027 PMCID: PMC5846552 DOI: 10.1080/15592324.2018.1441656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/15/2018] [Accepted: 01/29/2018] [Indexed: 06/08/2023]
Abstract
A recent study by Zlinszky et al., 1 uses high-resolution terrestrial laser scanning to investigate the variability of overnight movement of leaves and branches in vascular plants. This study finds among others that the investigated plants show periodic movements of around one centimetre in amplitude and 2-6 hour periodicity. Sub-circadian process dynamics of plants were so far not in focus of research, but here we compare the findings with other published cases of short-term periodicity in leaf turgor, sap flow and especially trunk diameter. Several authors have noted overnight variations in these parameters within periods of several hours and in absence of environmental changes with similar dynamics. We revisit the unknown questions of short-term plant movement and make a suggestion for future research.
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Affiliation(s)
- András Zlinszky
- Ecoinformatics and Biodiversity Section, Department of Bioscience, Aarhus University
- Balaton Limnological Institute, Centre for Ecological Research, Hungarian Academy of Sciences
| | - Anders Barfod
- Ecoinformatics and Biodiversity Section, Department of Bioscience, Aarhus University
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Abstract
Bacterial cytokinesis begins with the assembly of FtsZ into a Z ring at the center of the cell. The Z-ring constriction in Gram-negative bacteria may occur in an environment where the periplasm and the cytoplasm are isoosmotic, but in Gram-positive bacteria the constriction may have to overcome a substantial turgor pressure. We address three potential sources of invagination force. (1) FtsZ itself may generate force by curved protofilaments bending the attached membrane. This is sufficient to constrict liposomes in vitro. However, this force is on the order of a few pN, and would not be enough to overcome turgor. (2) Cell wall (CW) synthesis may generate force by pushing the plasma membrane from the outside. However, this would probably require some kind of Brownian ratchet to separate the CW and membrane sufficiently to allow a glycan strand to slip in. The elastic element is not obvious. (3) Excess membrane production has the potential to contribute significantly to the invagination force. If the excess membrane is produced under the CW, it would force the membrane to bleb inward. We propose here that a combination of FtsZ pulling from the inside, and excess membrane pushing membrane inward may generate a substantial constriction force at the division site. This combined force generation mechanism may be sufficient to overcome turgor pressure. This would abolish the need for a Brownian ratchet for CW growth, and would permit CW to operate by reinforcing the constrictions generated by FtsZ and excess membrane.
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Affiliation(s)
- Masaki Osawa
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
| | - Harold P Erickson
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
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Kampowski T, Mylo MD, Poppinga S, Speck T. How water availability influences morphological and biomechanical properties in the one-leaf plant Monophyllaea horsfieldii. R Soc Open Sci 2018; 5:171076. [PMID: 29410820 PMCID: PMC5792897 DOI: 10.1098/rsos.171076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/24/2017] [Indexed: 06/08/2023]
Abstract
In its natural habitat, the one-leaf plant Monophyllaea horsfieldii (Gesneriaceae) shows striking postural changes and dramatic loss of stability in response to intermittently occurring droughts. As the morphological, anatomical and biomechanical bases of these alterations are as yet unclear, we examined the influence of varying water contents on M. horsfieldii by conducting dehydration-rehydration experiments together with various imaging techniques as well as quantitative bending and turgor pressure measurements. As long as only moderate water stress was applied, gradual reductions in hypocotyl diameters and structural bending moduli during dehydration were almost always rapidly recovered in acropetal direction upon rehydration. On an anatomical scale, M. horsfieldii hypocotyls revealed substantial water stress-induced alterations in parenchymatous tissues, whereas the cell form and structure of epidermal and vascular tissues hardly changed. In summary, the functional morphology and biomechanics of M. horsfieldii hypocotyls directly correlated with water status alterations and associated physiological parameters (i.e. turgor pressure). Moreover, M. horsfieldii showed only little passive structural-functional adaptations to dehydration in comparison with poikilohydrous Ramonda myconi.
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Affiliation(s)
- Tim Kampowski
- Plant Biomechanics Group Freiburg, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany
- Freiburg Materials Research Center, University of Freiburg, Freiburg im Breisgau, Germany
| | - Max David Mylo
- Plant Biomechanics Group Freiburg, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany
| | - Simon Poppinga
- Plant Biomechanics Group Freiburg, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany
- Freiburg Materials Research Center, University of Freiburg, Freiburg im Breisgau, Germany
| | - Thomas Speck
- Plant Biomechanics Group Freiburg, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany
- Freiburg Materials Research Center, University of Freiburg, Freiburg im Breisgau, Germany
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Rojas ER, Huang KC, Theriot JA. Homeostatic Cell Growth Is Accomplished Mechanically through Membrane Tension Inhibition of Cell-Wall Synthesis. Cell Syst 2017; 5:578-590.e6. [PMID: 29203279 PMCID: PMC5985661 DOI: 10.1016/j.cels.2017.11.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Revised: 10/27/2017] [Accepted: 11/06/2017] [Indexed: 12/22/2022]
Abstract
Feedback mechanisms are required to coordinate balanced synthesis of subcellular components during cell growth. However, these coordination mechanisms are not apparent at steady state. Here, we elucidate the interdependence of cell growth, membrane tension, and cell-wall synthesis by observing their rapid re-coordination after osmotic shocks in Gram-positive bacteria. Single-cell experiments and mathematical modeling demonstrate that mechanical forces dually regulate cell growth: while turgor pressure produces mechanical stress within the cell wall that promotes its expansion through wall synthesis, membrane tension induces growth arrest by inhibiting wall synthesis. Tension inhibition occurs concurrently with membrane depolarization, and depolarization arrested growth independently of shock, indicating that electrical signals implement the negative feedback characteristic of homeostasis. Thus, competing influences of membrane tension and cell-wall mechanical stress on growth allow cells to rapidly correct for mismatches between membrane and wall synthesis rates, ensuring balanced growth.
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Affiliation(s)
- Enrique R Rojas
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
| | - Julie A Theriot
- Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Paljakka T, Jyske T, Lintunen A, Aaltonen H, Nikinmaa E, Hölttä T. Gradients and dynamics of inner bark and needle osmotic potentials in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst). Plant Cell Environ 2017; 40:2160-2173. [PMID: 28671720 DOI: 10.1111/pce.13017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 06/07/2023]
Abstract
Preconditions of phloem transport in conifers are relatively unknown. We studied the variation of needle and inner bark axial osmotic gradients and xylem water potential in Scots pine and Norway spruce by measuring needle and inner bark osmolality in saplings and mature trees over several periods within a growing season. The needle and inner bark osmolality was strongly related to xylem water potential in all studied trees. Sugar concentrations were measured in Scots pine, and they had similar dynamics to inner bark osmolality. The sucrose quantity remained fairly constant over time and position, whereas the other sugars exhibited a larger change with time and position. A small osmotic gradient existed from branch to stem base under pre-dawn conditions, and the osmotic gradient between upper stem and stem base was close to zero. The turgor in branches was significantly driven by xylem water potential, and the turgor loss point in branches was relatively close to daily minimum needle water potentials typically reported for Scots pine. Our results imply that xylem water potential considerably impacts the turgor pressure gradient driving phloem transport and that gravitation has a relatively large role in phloem transport in the stems of mature Scots pine trees.
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Affiliation(s)
- Teemu Paljakka
- Department of Forest Sciences, University of Helsinki, Helsinki, FI-00014, Finland
| | - Tuula Jyske
- Natural Resources Institute Finland (Luke), FI-02150, Espoo, Finland
| | - Anna Lintunen
- Department of Forest Sciences, University of Helsinki, Helsinki, FI-00014, Finland
| | - Heidi Aaltonen
- Department of Forest Sciences, University of Helsinki, Helsinki, FI-00014, Finland
| | - Eero Nikinmaa
- Department of Forest Sciences, University of Helsinki, Helsinki, FI-00014, Finland
| | - Teemu Hölttä
- Department of Forest Sciences, University of Helsinki, Helsinki, FI-00014, Finland
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Zait Y, Shapira O, Schwartz A. The effect of blue light on stomatal oscillations and leaf turgor pressure in banana leaves. Plant Cell Environ 2017; 40:1143-1152. [PMID: 28098339 DOI: 10.1111/pce.12907] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/02/2017] [Accepted: 01/04/2017] [Indexed: 06/06/2023]
Abstract
Stomatal oscillations are cyclic opening and closing of stomata, presumed to initiate from hydraulic mismatch between leaf water supply and transpiration rate. To test this assumption, mismatches between water supply and transpiration were induced using manipulations of vapour pressure deficit (VPD) and light spectrum in banana (Musa acuminata). Simultaneous measurements of gas exchange with changes in leaf turgor pressure were used to describe the hydraulic mismatches. An increase of VPD above a certain threshold caused stomatal oscillations with variable amplitudes. Oscillations in leaf turgor pressure were synchronized with stomatal oscillations and balanced only when transpiration equaled water supply. Surprisingly, changing the light spectrum from red and blue to red alone at constant VPD also induced stomatal oscillations - while the addition of blue (10%) to red light only ended oscillations. Blue light is known to induce stomatal opening and thus should increase the hydraulic mismatch, reduce the VPD threshold for oscillations and increase the oscillation amplitude. Unexpectedly, blue light reduced oscillation amplitude, increased VPD threshold and reduced turgor pressure loss. These results suggest that additionally, to the known effect of blue light on the hydroactive opening response of stomata, it can also effect stomatal movement by increased xylem-epidermis water supply.
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Affiliation(s)
- Yotam Zait
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Or Shapira
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Amnon Schwartz
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
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Coble AP, VanderWall B, Mau A, Cavaleri MA. How vertical patterns in leaf traits shift seasonally and the implications for modeling canopy photosynthesis in a temperate deciduous forest. Tree Physiol 2016; 36:1077-1091. [PMID: 27246164 DOI: 10.1093/treephys/tpw043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 04/12/2016] [Indexed: 06/05/2023]
Abstract
Leaf functional traits are used in modeling forest canopy photosynthesis (Ac) due to strong correlations between photosynthetic capacity, leaf mass per area (LMA) and leaf nitrogen per area (Narea). Vertical distributions of these traits may change over time in temperate deciduous forests as a result of acclimation to light, which may result in seasonal changes in Ac To assess both spatial and temporal variations in key traits, we measured vertical profiles of Narea and LMA from leaf expansion through leaf senescence in a sugar maple (Acer saccharum Marshall) forest. To investigate mechanisms behind coordinated changes in leaf morphology and function, we also measured vertical variation in leaf carbon isotope composition (δ(13)C), predawn turgor pressure, leaf water potential and osmotic potential. Finally, we assessed potential biases in Ac estimations by parameterizing models with and without vertical and seasonal Narea variations following leaf expansion. Our data are consistent with the hypothesis that hydrostatic constraints on leaf morphology drive the vertical increase in LMA with height early in the growing season; however, LMA in the upper canopy continued to increase over time during light acclimation, indicating that light is primarily driving gradients in LMA later in the growing season. Models with no seasonal variation in Narea overestimated Ac by up to 11% early in the growing season, while models with no vertical variation in Narea overestimated Ac by up to 60% throughout the season. According to the multilayer model, the upper 25% of leaf area contributed to over 50% of Ac, but when gradients of intercellular CO2, as estimated from δ(13)C, were accounted for, the upper 25% of leaf area contributed to 26% of total Ac Our results suggest that ignoring vertical variation of key traits can lead to considerable overestimation of Ac.
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Affiliation(s)
- Adam P Coble
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA Department of Natural Resources and the Environment, University of New Hampshire, 56 College Rd, Durham, NH 03824, USA
| | - Brittany VanderWall
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
| | - Alida Mau
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
| | - Molly A Cavaleri
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
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Goldenbogen B, Giese W, Hemmen M, Uhlendorf J, Herrmann A, Klipp E. Dynamics of cell wall elasticity pattern shapes the cell during yeast mating morphogenesis. Open Biol 2016; 6:160136. [PMID: 27605377 PMCID: PMC5043577 DOI: 10.1098/rsob.160136] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/08/2016] [Indexed: 12/17/2022] Open
Abstract
The cell wall defines cell shape and maintains integrity of fungi and plants. When exposed to mating pheromone, Saccharomyces cerevisiae grows a mating projection and alters in morphology from spherical to shmoo form. Although structural and compositional alterations of the cell wall accompany shape transitions, their impact on cell wall elasticity is unknown. In a combined theoretical and experimental approach using finite-element modelling and atomic force microscopy (AFM), we investigated the influence of spatially and temporally varying material properties on mating morphogenesis. Time-resolved elasticity maps of shmooing yeast acquired with AFM in vivo revealed distinct patterns, with soft material at the emerging mating projection and stiff material at the tip. The observed cell wall softening in the protrusion region is necessary for the formation of the characteristic shmoo shape, and results in wider and longer mating projections. The approach is generally applicable to tip-growing fungi and plants cells.
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Affiliation(s)
- Björn Goldenbogen
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Wolfgang Giese
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Marie Hemmen
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Jannis Uhlendorf
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Andreas Herrmann
- Molecular Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Edda Klipp
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
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Vogler H, Felekis D, Nelson BJ, Grossniklaus U. Measuring the Mechanical Properties of Plant Cell Walls. Plants (Basel) 2015; 4:167-82. [PMID: 27135321 DOI: 10.3390/plants4020167] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/05/2015] [Accepted: 03/11/2015] [Indexed: 11/21/2022]
Abstract
The size, shape and stability of a plant depend on the flexibility and integrity of its cell walls, which, at the same time, need to allow cell expansion for growth, while maintaining mechanical stability. Biomechanical studies largely vanished from the focus of plant science with the rapid progress of genetics and molecular biology since the mid-twentieth century. However, the development of more sensitive measurement tools renewed the interest in plant biomechanics in recent years, not only to understand the fundamental concepts of growth and morphogenesis, but also with regard to economically important areas in agriculture, forestry and the paper industry. Recent advances have clearly demonstrated that mechanical forces play a crucial role in cell and organ morphogenesis, which ultimately define plant morphology. In this article, we will briefly review the available methods to determine the mechanical properties of cell walls, such as atomic force microscopy (AFM) and microindentation assays, and discuss their advantages and disadvantages. But we will focus on a novel methodological approach, called cellular force microscopy (CFM), and its automated successor, real-time CFM (RT-CFM).
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Baccelli I. Cerato-platanin family proteins: one function for multiple biological roles? Front Plant Sci 2015; 5:769. [PMID: 25610450 PMCID: PMC4284994 DOI: 10.3389/fpls.2014.00769] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 12/12/2014] [Indexed: 05/24/2023]
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Moulia B, Coutand C, Julien JL. Mechanosensitive control of plant growth: bearing the load, sensing, transducing, and responding. Front Plant Sci 2015; 6:52. [PMID: 25755656 PMCID: PMC4337334 DOI: 10.3389/fpls.2015.00052] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 01/20/2015] [Indexed: 05/18/2023]
Abstract
As land plants grow and develop, they encounter complex mechanical challenges, especially from winds and turgor pressure. Mechanosensitive control over growth and morphogenesis is an adaptive trait, reducing the risks of breakage or explosion. This control has been mostly studied through experiments with artificial mechanical loads, often focusing on cellular or molecular mechanotransduction pathway. However, some important aspects of mechanosensing are often neglected. (i) What are the mechanical characteristics of different loads and how are loads distributed within different organs? (ii) What is the relevant mechanical stimulus in the cell? Is it stress, strain, or energy? (iii) How do mechanosensing cells signal to meristematic cells? Without answers to these questions we cannot make progress analyzing the mechanobiological effects of plant size, plant shape, tissue distribution and stiffness, or the magnitude of stimuli. This situation is rapidly changing however, as systems mechanobiology is being developed, using specific biomechanical and/or mechanobiological models. These models are instrumental in comparing loads and responses between experiments and make it possible to quantitatively test biological hypotheses describing the mechanotransduction networks. This review is designed for a general plant science audience and aims to help biologists master the models they need for mechanobiological studies. Analysis and modeling is broken down into four steps looking at how the structure bears the load, how the distributed load is sensed, how the mechanical signal is transduced, and then how the plant responds through growth. Throughout, two examples of adaptive responses are used to illustrate this approach: the thigmorphogenetic syndrome of plant shoots bending and the mechanosensitive control of shoot apical meristem (SAM) morphogenesis. Overall this should provide a generic understanding of systems mechanobiology at work.
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Affiliation(s)
- Bruno Moulia
- NRA, UMR 547 PIAFClermont-Ferrand, France
- Clermont Université, Université Blaise Pascal, UMR 547 PIAFClermont-Ferrand, France
- *Correspondence: Bruno Moulia, UMR, PIAF Integrative Physics and Physiology of Trees, Institut National de la Recherche Agronomique, 5 chemin de Beaulieu, F-63039 Clermont-Ferrand, France e-mail:
| | - Catherine Coutand
- NRA, UMR 547 PIAFClermont-Ferrand, France
- Clermont Université, Université Blaise Pascal, UMR 547 PIAFClermont-Ferrand, France
| | - Jean-Louis Julien
- NRA, UMR 547 PIAFClermont-Ferrand, France
- Clermont Université, Université Blaise Pascal, UMR 547 PIAFClermont-Ferrand, France
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Beauzamy L, Louveaux M, Hamant O, Boudaoud A. Mechanically, the Shoot Apical Meristem of Arabidopsis Behaves like a Shell Inflated by a Pressure of About 1 MPa. Front Plant Sci 2015; 6:1038. [PMID: 26635855 PMCID: PMC4659900 DOI: 10.3389/fpls.2015.01038] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 11/09/2015] [Indexed: 05/15/2023]
Abstract
In plants, the shoot apical meristem contains the stem cells and is responsible for the generation of all aerial organs. Mechanistically, organogenesis is associated with an auxin-dependent local softening of the epidermis. This has been proposed to be sufficient to trigger outgrowth, because the epidermis is thought to be under tension and stiffer than internal tissues in all the aerial part of the plant. However, this has not been directly demonstrated in the shoot apical meristem. Here we tested this hypothesis in Arabidopsis using indentation methods and modeling. We considered two possible scenarios: either the epidermis does not have unique properties and the meristem behaves as a homogeneous linearly-elastic tissue, or the epidermis is under tension and the meristem exhibits the response of a shell under pressure. Large indentation depths measurements with a large tip (~size of the meristem) were consistent with a shell-like behavior. This also allowed us to deduce a value of turgor pressure, estimated at 0.82±0.16 MPa. Indentation with atomic force microscopy provided local measurements of pressure in the epidermis, further confirming the range of values obtained from large deformations. Altogether, our data demonstrate that the Arabidopsis shoot apical meristem behaves like a shell under a MPa range pressure and support a key role for the epidermis in shaping the shoot apex.
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Affiliation(s)
- Léna Beauzamy
- Laboratoire Reproduction et Développement des Plantes, INRA, Centre National de la Recherche Scientifique, ENS de Lyon, UCB Lyon 1, Université de LyonLyon, France
- Laboratoire Joliot-Curie, Centre National de la Recherche Scientifique, ENS de Lyon, Université de LyonLyon, France
| | - Marion Louveaux
- Laboratoire Reproduction et Développement des Plantes, INRA, Centre National de la Recherche Scientifique, ENS de Lyon, UCB Lyon 1, Université de LyonLyon, France
- Laboratoire Joliot-Curie, Centre National de la Recherche Scientifique, ENS de Lyon, Université de LyonLyon, France
| | - Olivier Hamant
- Laboratoire Reproduction et Développement des Plantes, INRA, Centre National de la Recherche Scientifique, ENS de Lyon, UCB Lyon 1, Université de LyonLyon, France
- Laboratoire Joliot-Curie, Centre National de la Recherche Scientifique, ENS de Lyon, Université de LyonLyon, France
| | - Arezki Boudaoud
- Laboratoire Reproduction et Développement des Plantes, INRA, Centre National de la Recherche Scientifique, ENS de Lyon, UCB Lyon 1, Université de LyonLyon, France
- Laboratoire Joliot-Curie, Centre National de la Recherche Scientifique, ENS de Lyon, Université de LyonLyon, France
- Institut Universitaire de FranceParis, France
- *Correspondence: Arezki Boudaoud
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50
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Beauzamy L, Nakayama N, Boudaoud A. Flowers under pressure: ins and outs of turgor regulation in development. Ann Bot 2014; 114:1517-33. [PMID: 25288632 PMCID: PMC4204789 DOI: 10.1093/aob/mcu187] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 08/01/2014] [Indexed: 05/18/2023]
Abstract
BACKGROUND Turgor pressure is an essential feature of plants; however, whereas its physiological importance is unequivocally recognized, its relevance to development is often reduced to a role in cell elongation. SCOPE This review surveys the roles of turgor in development, the molecular mechanisms of turgor regulation and the methods used to measure turgor and related quantities, while also covering the basic concepts associated with water potential and water flow in plants. Three key processes in flower development are then considered more specifically: flower opening, anther dehiscence and pollen tube growth. CONCLUSIONS Many molecular determinants of turgor and its regulation have been characterized, while a number of methods are now available to quantify water potential, turgor and hydraulic conductivity. Data on flower opening, anther dehiscence and lateral root emergence suggest that turgor needs to be finely tuned during development, both spatially and temporally. It is anticipated that a combination of biological experiments and physical measurements will reinforce the existing data and reveal unexpected roles of turgor in development.
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Affiliation(s)
- Léna Beauzamy
- Reproduction et Développement des Plantes, INRA, CNRS, ENS de Lyon, UCBL Lyon I, 46 Allée d'Italie, 69364 Lyon Cedex 07, France Laboratoire Joliot-Curie, CNRS, ENS de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Naomi Nakayama
- Reproduction et Développement des Plantes, INRA, CNRS, ENS de Lyon, UCBL Lyon I, 46 Allée d'Italie, 69364 Lyon Cedex 07, France Laboratoire Joliot-Curie, CNRS, ENS de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France Institute of Molecular Plant Sciences, University of Edinburgh, Mayfield Rd, King's Buildings, Edinburgh EH9 3JH, UK
| | - Arezki Boudaoud
- Reproduction et Développement des Plantes, INRA, CNRS, ENS de Lyon, UCBL Lyon I, 46 Allée d'Italie, 69364 Lyon Cedex 07, France Laboratoire Joliot-Curie, CNRS, ENS de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
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