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Gao X, Yang B, Zhang J, Wang C, Ren H, Fu Y, Yang Z. PLEIOTROPIC REGULATORY LOCUS1 maintains actin microfilament integrity to regulate pavement cell morphogenesis. PLANT PHYSIOLOGY 2024; 195:356-369. [PMID: 38227494 DOI: 10.1093/plphys/kiae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 01/17/2024]
Abstract
Actin dynamics are critical for plant cell morphogenesis, but the underlying signaling mechanisms regulating these dynamics are not well understood. Here, we established that PLEIOTROPIC REGULATORY LOCUS1 (PRL1) modulates leaf pavement cell (PC) morphogenesis in Arabidopsis (Arabidopsis thaliana) by maintaining the dynamic homeostasis of actin microfilaments (MF). Our previous studies indicated that PC shape was determined by antagonistic RHO-RELATED GTPase FROM PLANTS 2 (ROP2) and RHO-RELATED GTPase FROM PLANTS 6 (ROP6) signaling pathways that promote cortical MF and microtubule organization, respectively. Our genetic screen for additional components in ROP6-mediated signaling identified prl1 alleles. Genetic analysis confirmed that PRL1 plays a key role in PC morphogenesis. Mutations in PRL1 caused cortical MF depolymerization, resulting in defective PC morphogenesis. Further genetic analysis revealed that PRL1 is epistatic to ROP2 and ROP6 in PC morphogenesis. Mutations in PRL1 enhanced the effects of ROP2 and ROP6 in PC morphogenesis, leading to a synergistic phenotype in the PCs of ROP2 prl1 and ROP6 prl1. Furthermore, the activities of ROP2 and ROP6 were differentially altered in prl1 mutants, suggesting that ROP2 and ROP6 function downstream of PRL1. Additionally, cortical MF depolymerization in prl1 mutants occurred independently of ROP2 and ROP6, implying that these proteins impact PC morphogenesis in the prl1 mutant through other cellular processes. Our research indicates that PRL1 preserves the structural integrity of actin and facilitates pavement cell morphogenesis in Arabidopsis.
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Affiliation(s)
- Xiaowei Gao
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Bo Yang
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jingjing Zhang
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chi Wang
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Huibo Ren
- Basic Forestry and Proteomics Research Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ying Fu
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhenbiao Yang
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA
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Smithers ET, Luo J, Dyson RJ. A continuum mechanics model of the plant cell wall reveals interplay between enzyme action and cell wall structure. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2024; 47:1. [PMID: 38183519 PMCID: PMC10771620 DOI: 10.1140/epje/s10189-023-00396-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 12/11/2023] [Indexed: 01/08/2024]
Abstract
Plant cell growth is regulated through manipulation of the cell wall network, which consists of oriented cellulose microfibrils embedded within a ground matrix incorporating pectin and hemicellulose components. There remain many unknowns as to how this manipulation occurs. Experiments have shown that cellulose reorients in cell walls as the cell expands, while recent data suggest that growth is controlled by distinct collections of hemicellulose called biomechanical hotspots, which join the cellulose molecule together. The enzymes expansin and Cel12A have both been shown to induce growth of the cell wall; however, while Cel12A's wall-loosening action leads to a reduction in the cell wall strength, expansin's has been shown to increase the strength of the cell wall. In contrast, members of the XTH enzyme family hydrolyse hemicellulose but do not appear to cause wall creep. This experimentally observed behaviour still awaits a full explanation. We derive and analyse a mathematical model for the effective mechanical properties of the evolving cell wall network, incorporating cellulose microfibrils, which reorient with cell growth and are linked via biomechanical hotspots made up of regions of crosslinking hemicellulose. Assuming a visco-elastic response for the cell wall and using a continuum approach, we calculate the total stress resultant of the cell wall for a given overall growth rate. By changing appropriate parameters affecting breakage rate and viscous properties, we provide evidence for the biomechanical hotspot hypothesis and develop mechanistic understanding of the growth-inducing enzymes.
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Affiliation(s)
- Euan T Smithers
- School of Mathematics, University of Birmingham, Birmingham, B15 2TT, UK.
- Sainsbury Laboratory, University of Cambridge, Bateman street, Cambridge, CB2 1LR, Cambridgeshire, UK.
| | - Jingxi Luo
- School of Mathematics, University of Birmingham, Birmingham, B15 2TT, UK
| | - Rosemary J Dyson
- School of Mathematics, University of Birmingham, Birmingham, B15 2TT, UK
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Piovesan A, Vancauwenberghe V, Van De Looverbosch T, Verboven P, Nicolaï B. X-ray computed tomography for 3D plant imaging. TRENDS IN PLANT SCIENCE 2021; 26:1171-1185. [PMID: 34404587 DOI: 10.1016/j.tplants.2021.07.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/05/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
X-ray computed tomography (CT) is a valuable tool for 3D imaging of plant tissues and organs. Applications include the study of plant development and organ morphogenesis, as well as modeling of transport processes in plants. Some challenges remain, however, including attaining higher contrast for easier quantification, increasing the resolution for imaging subcellular features, and decreasing image acquisition and processing time for high-throughput phenotyping. In addition, phase contrast, multispectral, dark-field, soft X-ray, and time-resolved imaging are emerging. At the same time, a large amount of 3D image data are becoming available, posing challenges for data management. We review recent advances in the area of X-ray CT for plant imaging, and describe opportunities for using such images for studying transport processes in plants.
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Affiliation(s)
- Agnese Piovesan
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium
| | - Valérie Vancauwenberghe
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium
| | - Tim Van De Looverbosch
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium
| | - Pieter Verboven
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium.
| | - Bart Nicolaï
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium; Flanders Centre of Postharvest Technology (VCBT), Willem de Croylaan 42, BE-3001 Leuven, Belgium
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Chen MJ, Kimpton LS, Whiteley JP, Castilho M, Malda J, Please CP, Waters SL, Byrne HM. Multiscale modelling and homogenisation of fibre-reinforced hydrogels for tissue engineering. EUROPEAN JOURNAL OF APPLIED MATHEMATICS 2020; 31:143-171. [PMID: 33149377 PMCID: PMC7116294 DOI: 10.1017/s0956792518000657] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Tissue engineering aims to grow artificial tissues in vitro to replace those in the body that have been damaged through age, trauma or disease. A recent approach to engineer artificial cartilage involves seeding cells within a scaffold consisting of an interconnected 3D-printed lattice of polymer fibres combined with a cast or printed hydrogel, and subjecting the construct (cell-seeded scaffold) to an applied load in a bioreactor. A key question is to understand how the applied load is distributed throughout the construct. To address this, we employ homogenisation theory to derive equations governing the effective macroscale material properties of a periodic, elastic-poroelastic composite. We treat the fibres as a linear elastic material and the hydrogel as a poroelastic material, and exploit the disparate length scales (small inter-fibre spacing compared with construct dimensions) to derive macroscale equations governing the response of the composite to an applied load. This homogenised description reflects the orthotropic nature of the composite. To validate the model, solutions from finite element simulations of the macroscale, homogenised equations are compared to experimental data describing the unconfined compression of the fibre-reinforced hydrogels. The model is used to derive the bulk mechanical properties of a cylindrical construct of the composite material for a range of fibre spacings and to determine the local mechanical environment experienced by cells embedded within the construct.
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Affiliation(s)
- M. J. Chen
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
- School of Mathematical Sciences, The University of Adelaide, North Terrace, Adelaide SA 5005, Australia
| | - L. S. Kimpton
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
| | - J. P. Whiteley
- Department of Computer Science, University of Oxford, Wolfson Building, Parks Road, Oxford OX1 3QD, UK
| | - M. Castilho
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - J. Malda
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - C. P. Please
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
| | - S. L. Waters
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
| | - H. M. Byrne
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
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Bidhendi AJ, Geitmann A. Methods to quantify primary plant cell wall mechanics. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3615-3648. [PMID: 31301141 DOI: 10.1093/jxb/erz281] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 06/26/2019] [Indexed: 05/23/2023]
Abstract
The primary plant cell wall is a dynamically regulated composite material of multiple biopolymers that forms a scaffold enclosing the plant cells. The mechanochemical make-up of this polymer network regulates growth, morphogenesis, and stability at the cell and tissue scales. To understand the dynamics of cell wall mechanics, and how it correlates with cellular activities, several experimental frameworks have been deployed in recent years to quantify the mechanical properties of plant cells and tissues. Here we critically review the application of biomechanical tool sets pertinent to plant cell mechanics and outline some of their findings, relevance, and limitations. We also discuss methods that are less explored but hold great potential for the field, including multiscale in silico mechanical modeling that will enable a unified understanding of the mechanical behavior across the scales. Our overview reveals significant differences between the results of different mechanical testing techniques on plant material. Specifically, indentation techniques seem to consistently report lower values compared with tensile tests. Such differences may in part be due to inherent differences among the technical approaches and consequently the wall properties that they measure, and partly due to differences between experimental conditions.
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Affiliation(s)
- Amir J Bidhendi
- Department of Plant Science, McGill University, Macdonald Campus, Lakeshore, Ste-Anne-de-Bellevue, Québec, Canada
- Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, Montreal, Quebec, Canada
| | - Anja Geitmann
- Department of Plant Science, McGill University, Macdonald Campus, Lakeshore, Ste-Anne-de-Bellevue, Québec, Canada
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Smithers ET, Luo J, Dyson RJ. Mathematical principles and models of plant growth mechanics: from cell wall dynamics to tissue morphogenesis. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3587-3600. [PMID: 31128070 DOI: 10.1093/jxb/erz253] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
Plant growth research produces a catalogue of complex open questions. We argue that plant growth is a highly mechanical process, and that mathematics gives an underlying framework with which to probe its fundamental unrevealed mechanisms. This review serves to illustrate the biological insights afforded by mathematical modelling and demonstrate the breadth of mathematically rich problems available within plant sciences, thereby promoting a mutual appreciation across the disciplines. On the one hand, we explain the general mathematical principles behind mechanical growth models; on the other, we describe how modelling addresses specific problems in microscale cell wall mechanics, tip growth, morphogenesis, and stress feedback. We conclude by identifying possible future directions for both biologists and mathematicians, including as yet unanswered questions within various topics, stressing that interdisciplinary collaboration is vital for tackling the challenge of understanding plant growth mechanics.
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Affiliation(s)
- Euan T Smithers
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham, UK
| | - Jingxi Luo
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham, UK
| | - Rosemary J Dyson
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham, UK
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