1
|
Lundquist CR, Rudall PJ, Sukri RS, Conejero M, Smith A, Lopez-Garcia M, Vignolini S, Metali F, Whitney HM. Living jewels: iterative evolution of iridescent blue leaves from helicoidal cell walls. ANNALS OF BOTANY 2024; 134:131-150. [PMID: 38551515 PMCID: PMC11161568 DOI: 10.1093/aob/mcae045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 04/15/2024] [Indexed: 06/09/2024]
Abstract
BACKGROUND AND AIMS Structural colour is responsible for the remarkable metallic blue colour seen in the leaves of several plants. Species belonging to only ten genera have been investigated to date, revealing four photonic structures responsible for structurally coloured leaves. One of these is the helicoidal cell wall, known to create structural colour in the leaf cells of five taxa. Here we investigate a broad selection of land plants to understand the phylogenetic distribution of this photonic structure in leaves. METHODS We identified helicoidal structures in the leaf epidermal cells of 19 species using transmission electron microscopy. Pitch measurements of the helicoids were compared with the reflectance spectra of circularly polarized light from the cells to confirm the structure-colour relationship. RESULTS By incorporating species examined with a polarizing filter, our results increase the number of taxa with photonic helicoidal cell walls to species belonging to at least 35 genera. These include 19 monocot genera, from the orders Asparagales (Orchidaceae) and Poales (Cyperaceae, Eriocaulaceae, Rapateaceae) and 16 fern genera, from the orders Marattiales (Marattiaceae), Schizaeales (Anemiaceae) and Polypodiales (Blechnaceae, Dryopteridaceae, Lomariopsidaceae, Polypodiaceae, Pteridaceae, Tectariaceae). CONCLUSIONS Our investigation adds considerably to the recorded diversity of plants with structurally coloured leaves. The iterative evolution of photonic helicoidal walls has resulted in a broad phylogenetic distribution, centred on ferns and monocots. We speculate that the primary function of the helicoidal wall is to provide strength and support, so structural colour could have evolved as a potentially beneficial chance function of this structure.
Collapse
Affiliation(s)
- Clive R Lundquist
- School of Biological Sciences, University of Bristol, Bristol, UK
- Jodrell Laboratory, Royal Botanic Gardens Kew, Richmond, Surrey, UK
| | - Paula J Rudall
- Jodrell Laboratory, Royal Botanic Gardens Kew, Richmond, Surrey, UK
| | - Rahayu S Sukri
- Faculty of Science, Universiti Brunei Darussalam, Bandar Seri Begawan, Brunei Darussalam
| | - María Conejero
- Jodrell Laboratory, Royal Botanic Gardens Kew, Richmond, Surrey, UK
| | - Alyssa Smith
- Department of Chemistry, University of Cambridge, UK
| | - Martin Lopez-Garcia
- Department of Nanophotonics, International Iberian Nanotechnology Laboratory, 4715-330 Braga, Portugal
| | - Silvia Vignolini
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Faizah Metali
- Faculty of Science, Universiti Brunei Darussalam, Bandar Seri Begawan, Brunei Darussalam
| | | |
Collapse
|
2
|
Sleboda DA, Geitmann A, Sharif-Naeini R. Multiscale structural anisotropy steers plant organ actuation. Curr Biol 2023; 33:639-646.e3. [PMID: 36608688 DOI: 10.1016/j.cub.2022.12.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/30/2022] [Accepted: 12/07/2022] [Indexed: 01/07/2023]
Abstract
Leaf movement in vascular plants is executed by joint-like structures called pulvini. Many structural features of pulvini have been described at subcellular, cellular, and tissue scales of organization; however, how the characteristic hierarchical architecture of plant tissue influences pulvinus-mediated actuation remains poorly understood. To investigate the influence of multiscale structure on turgor-driven pulvinus movements, we visualized Mimosa pudica pulvinus morphology and anatomy at multiple hierarchical scales of organization and used osmotic perturbations to experimentally swell pulvini in incremental states of dissection. We observed directional cellulose microfibril reinforcement, oblong, spindle-shaped primary pit fields, and longitudinally slightly compressed cell geometries in the parenchyma of M. pudica. Consistent with these observations, isolated parenchyma tissues displayed highly anisotropic swelling behaviors indicating a high degree of mechanical anisotropy. Swelling behaviors at higher scales of pulvinus organization were also influenced by the presence of the pulvinus epidermis, which displayed oblong epidermal cells oriented transverse to the pulvinus long axis. Our findings indicate that structural specializations spanning multiple hierarchical scales of organization guide hydraulic deformation of pulvini, suggesting that multiscale mechanics are crucial to the translation of cell-level turgor variations into organ-scale pulvinus motion in vivo.
Collapse
Affiliation(s)
- David A Sleboda
- Department of Physiology, McGill University, 3649 Promenade Sir William Osler, Montreal, QC H3G 0B1, Canada; Department of Plant Science, McGill University, 21111 Rue Lakeshore, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada.
| | - Anja Geitmann
- Department of Plant Science, McGill University, 21111 Rue Lakeshore, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada.
| | - Reza Sharif-Naeini
- Department of Physiology, McGill University, 3649 Promenade Sir William Osler, Montreal, QC H3G 0B1, Canada
| |
Collapse
|
3
|
Chen B, Dang X, Bai W, Liu M, Li Y, Zhu L, Yang Y, Yu P, Ren H, Huang D, Pan X, Wang H, Qin Y, Feng S, Wang Q, Lin D. The IPGA1-ANGUSTIFOLIA module regulates microtubule organisation and pavement cell shape in Arabidopsis. THE NEW PHYTOLOGIST 2022; 236:1310-1325. [PMID: 35975703 DOI: 10.1111/nph.18433] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
Plant cells continuously experience mechanical stress resulting from the cell wall that bears internal turgor pressure. Cortical microtubules align with the predicted maximal tensile stress direction to guide cellulose biosynthesis and therefore results in cell wall reinforcement. We have previously identified Increased Petal Growth Anisotropy (IPGA1) as a putative microtubule-associated protein in Arabidopsis, but the function of IPGA1 remains unclear. Here, using the Arabidopsis cotyledon pavement cell as a model, we demonstrated that IPGA1 forms protein granules and interacts with ANGUSTIFOLIA (AN) to cooperatively regulate microtubule organisation in response to stress. Application of mechanical perturbations, such as cell ablation, led to microtubule reorganisation into aligned arrays in wild-type cells. This microtubule response to stress was enhanced in the IPGA1 loss-of-function mutant. Mechanical perturbations promoted the formation of IPGA1 granules on microtubules. We further showed that IPGA1 physically interacted with AN both in vitro and on microtubules. The ipga1 mutant alleles exhibited reduced interdigitated growth of pavement cells, with smooth shape. IPGA1 and AN had a genetic interaction in regulating pavement cell shape. Furthermore, IPGA1 genetically and physically interacted with the microtubule-severing enzyme KATANIN. We propose that the IPGA1-AN module regulates microtubule organisation and pavement cell shape.
Collapse
Affiliation(s)
- Binqing Chen
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, China
| | - Xie Dang
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wenting Bai
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Min Liu
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Ying Li
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lilan Zhu
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yanqiu Yang
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- Agricultural Ecology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, 350013, China
| | - Peihang Yu
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Huibo Ren
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Dingquan Huang
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xue Pan
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
| | - Haifeng Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530004, China
| | - Yuan Qin
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Shiliang Feng
- Smart Materials and Advanced Structure Laboratory, School of Mechanical Engineering and Mechanics, Ningbo University, Ningbo, 315211, China
| | - Qin Wang
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Deshu Lin
- Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| |
Collapse
|
4
|
Pfaff SA, Wang X, Wagner ER, Wilson LA, Kiemle SN, Cosgrove DJ. Detecting the orientation of newly-deposited crystalline cellulose with fluorescent CBM3. Cell Surf 2022; 8:100089. [DOI: 10.1016/j.tcsw.2022.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/10/2022] [Accepted: 11/11/2022] [Indexed: 11/15/2022] Open
|
5
|
Cosgrove D. Plant biology: Peering deeply into the structure of the onion epidermal cell wall. Curr Biol 2022; 32:R515-R517. [PMID: 35671723 DOI: 10.1016/j.cub.2022.04.087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cell wall ultrastructure has previously been assessed by thin-section transmission electron microscopy and by surface-based methods, such as atomic force microscopy. A new study uses electron tomography to image cellulose and pectin organization deep inside a thick epidermal cell wall.
Collapse
Affiliation(s)
- Daniel Cosgrove
- Department of Biology, Pennsylvania State University, University Park, PA, USA.
| |
Collapse
|
6
|
Cell wall composition determines handedness reversal in helicoidal cellulose architectures of Pollia condensata fruits. Proc Natl Acad Sci U S A 2021; 118:2111723118. [PMID: 34911759 PMCID: PMC8713805 DOI: 10.1073/pnas.2111723118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2021] [Indexed: 11/18/2022] Open
Abstract
Helicoidal architectures are widespread in nature; several species adopt this structure to produce brilliant colorations. Such chiral architectures are usually left-handed in plants, with the only exception found in the cell walls of epicarp cells of Pollia condensata, where both handednesses are observed. Here, we aim to understand the origin of handednesses by analyzing optical and mechanical responses of single cells. Surprisingly, we discover that left-handed and right-handed cells show different distributions of spectra and elasticity. We verified by using finite element analysis simulation that the elasticity of helicoids is sensitive to the ratio of cellulose/cell wall matrix. Our findings reveal that cell wall composition affects the helicoidal architectures, suggesting that chemical composition plays a role in morphogenesis of the chirality reversal. Chiral asymmetry is important in a wide variety of disciplines and occurs across length scales. While several natural chiral biomolecules exist only with single handedness, they can produce complex hierarchical structures with opposite chiralities. Understanding how the handedness is transferred from molecular to the macroscopic scales is far from trivial. An intriguing example is the transfer of the handedness of helicoidal organizations of cellulose microfibrils in plant cell walls. These cellulose helicoids produce structural colors if their dimension is comparable to the wavelength of visible light. All previously reported examples of a helicoidal structure in plants are left-handed except, remarkably, in the Pollia condensata fruit; both left- and right-handed helicoidal cell walls are found in neighboring cells of the same tissue. By simultaneously studying optical and mechanical responses of cells with different handednesses, we propose that the chirality of helicoids results from differences in cell wall composition. In detail, here we showed statistical substantiation of three different observations: 1) light reflected from right-handed cells is red shifted compared to light reflected from left-handed cells, 2) right-handed cells occur more rarely than left-handed ones, and 3) right-handed cells are located mainly in regions corresponding to interlocular divisions. Finally, 4) right-handed cells have an average lower elastic modulus compared to left-handed cells of the same color. Our findings, combined with mechanical simulation, suggest that the different chiralities of helicoids in the cell wall may result from different chemical composition, which strengthens previous hypotheses that hemicellulose might mediate the rotations of cellulose microfibrils.
Collapse
|
7
|
Integument-Specific Transcriptional Regulation in the Mid-Stage of Flax Seed Development Influences the Release of Mucilage and the Seed Oil Content. Cells 2021; 10:cells10102677. [PMID: 34685657 PMCID: PMC8534900 DOI: 10.3390/cells10102677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022] Open
Abstract
Flax (Linum usitatissimum L.) seed oil, which accumulates in the embryo, and mucilage, which is synthesized in the seed coat, are of great economic importance for food, pharmaceutical as well as chemical industries. Theories on the link between oil and mucilage production in seeds consist in the spatio-temporal competition of both compounds for photosynthates during the very early stages of seed development. In this study, we demonstrate a positive relationship between seed oil production and seed coat mucilage extrusion in the agronomic model, flax. Three recombinant inbred lines were selected for low, medium and high mucilage and seed oil contents. Metabolite and transcript profiling (1H NMR and DNA oligo-microarrays) was performed on the seeds during seed development. These analyses showed main changes in the seed coat transcriptome during the mid-phase of seed development (25 Days Post-Anthesis), once the mucilage biosynthesis and modification processes are thought to be finished. These transcriptome changes comprised genes that are putatively involved in mucilage chemical modification and oil synthesis, as well as gibberellic acid (GA) metabolism. The results of this integrative biology approach suggest that transcriptional regulations of seed oil and fatty acid (FA) metabolism could occur in the seed coat during the mid-stage of seed development, once the seed coat carbon supplies have been used for mucilage biosynthesis and mechanochemical properties of the mucilage secretory cells.
Collapse
|
8
|
Xiao N, Felhofer M, Antreich SJ, Huss JC, Mayer K, Singh A, Bock P, Gierlinger N. Twist and lock: nutshell structures for high strength and energy absorption. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210399. [PMID: 34430046 PMCID: PMC8355673 DOI: 10.1098/rsos.210399] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/20/2021] [Indexed: 05/04/2023]
Abstract
Nutshells achieve remarkable properties by optimizing structure and chemistry at different hierarchical levels. Probing nutshells from the cellular down to the nano- and molecular level by microchemical and nanomechanical imaging techniques reveals insights into nature's packing concepts. In walnut and pistachio shells, carbohydrate and lignin polymers assemble to form thick-walled puzzle cells, which interlock three-dimensionally and show high tissue strength. Pistachio additionally achieves high-energy absorption by numerous lobes interconnected via ball-joint-like structures. By contrast, the three times more lignified walnut shells show brittle LEGO-brick failure, often along the numerous pit channels. In both species, cell walls (CWs) show distinct lamellar structures. These lamellae involve a helicoidal arrangement of cellulose macrofibrils as a recurring motif. Between the two nutshell species, these lamellae show differences in thickness and pitch angle, which can explain the different mechanical properties on the nanolevel. Our in-depth study of the two nutshell tissues highlights the role of cell form and their interlocking as well as plant CW composition and structure for mechanical protection. Understanding these plant shell concepts might inspire biomimetic material developments as well as using walnut and pistachio shell waste as sustainable raw material in future applications.
Collapse
Affiliation(s)
- Nannan Xiao
- Institute of Biophysics, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria
| | - Martin Felhofer
- Institute of Biophysics, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria
| | - Sebastian J. Antreich
- Institute of Biophysics, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria
| | - Jessica C. Huss
- Institute of Biophysics, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria
| | - Konrad Mayer
- Institute of Biophysics, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria
| | - Adya Singh
- Institute of Biophysics, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria
| | - Peter Bock
- Institute of Biophysics, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria
| | - Notburga Gierlinger
- Institute of Biophysics, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria
| |
Collapse
|
9
|
Xin A, Fry SC. Cutin:xyloglucan transacylase (CXT) activity covalently links cutin to a plant cell-wall polysaccharide. JOURNAL OF PLANT PHYSIOLOGY 2021; 262:153446. [PMID: 34051591 DOI: 10.1016/j.jplph.2021.153446] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 05/26/2023]
Abstract
The shoot epidermal cell wall in land-plants is associated with a polyester, cutin, which controls water loss and possibly organ expansion. Covalent bonds between cutin and its neighbouring cell-wall polysaccharides have long been proposed. However, the lack of biochemical evidence makes cutin-polysaccharide linkages largely conjectural. Here we optimised a portfolio of radiochemical assays to look for cutin-polysaccharide ester bonds in the epidermis of pea epicotyls, ice-plant leaves and tomato fruits, based on the hypothesis that a transacylase remodels cutin in a similar fashion to cutin synthase and cutin:cutin transacylase activities. Through in-situ enzyme assays and chemical degradations coupled with chromatographic analysis of the 3H-labelled products, we observed that among several wall-related oligosaccharides tested, only a xyloglucan oligosaccharide ([3H]XXXGol) could acquire ester-bonds from endogenous cutin, suggesting a cutin:xyloglucan transacylase (CXT). CXT activity was heat-labile, time-dependent, and maximal at near-neutral pH values. In-situ CXT activity peaked in nearly fully expanded tomato fruits and ice-plant leaves. CXT activity positively correlated with organ growth rate, suggesting that it contributes to epidermal integrity during rapid expansion. This study uncovers hitherto unappreciated re-structuring processes in the plant epidermis and provides a step towards the identification of CXT and its engineering for biotechnological applications.
Collapse
Affiliation(s)
- Anzhou Xin
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Stephen C Fry
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK.
| |
Collapse
|
10
|
Xin A, Fei Y, Molnar A, Fry SC. Cutin:cutin-acid endo-transacylase (CCT), a cuticle-remodelling enzyme activity in the plant epidermis. Biochem J 2021; 478:777-798. [PMID: 33511979 PMCID: PMC7925011 DOI: 10.1042/bcj20200835] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/17/2021] [Accepted: 01/28/2021] [Indexed: 01/08/2023]
Abstract
Cutin is a polyester matrix mainly composed of hydroxy-fatty acids that occurs in the cuticles of shoots and root-caps. The cuticle, of which cutin is a major component, protects the plant from biotic and abiotic stresses, and cutin has been postulated to constrain organ expansion. We propose that, to allow cutin restructuring, ester bonds in this net-like polymer can be transiently cleaved and then re-formed (transacylation). Here, using pea epicotyl epidermis as the main model, we first detected a cutin:cutin-fatty acid endo-transacylase (CCT) activity. In-situ assays used endogenous cutin as the donor substrate for endogenous enzymes; the exogenous acceptor substrate was a radiolabelled monomeric cutin-acid, 16-hydroxy-[3H]hexadecanoic acid (HHA). High-molecular-weight cutin became ester-bonded to intact [3H]HHA molecules, which thereby became unextractable except by ester-hydrolysing alkalis. In-situ CCT activity correlated with growth rate in Hylotelephium leaves and tomato fruits, suggesting a role in loosening the outer epidermal wall during organ growth. The only well-defined cutin transacylase in the apoplast, CUS1 (a tomato cutin synthase), when produced in transgenic tobacco, lacked CCT activity. This finding provides a reference for future CCT protein identification, which can adopt our sensitive enzyme assay to screen other CUS1-related enzymes.
Collapse
Affiliation(s)
- Anzhou Xin
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh EH9 3BF, U.K
| | - Yue Fei
- Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh EH9 3BF, U.K
| | - Attila Molnar
- Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh EH9 3BF, U.K
| | - Stephen C. Fry
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh EH9 3BF, U.K
| |
Collapse
|
11
|
Lin W, Yang Z. Unlocking the mechanisms behind the formation of interlocking pavement cells. CURRENT OPINION IN PLANT BIOLOGY 2020; 57:142-154. [PMID: 33128897 DOI: 10.1016/j.pbi.2020.09.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 08/30/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
The leaf epidermal pavement cells with the puzzle-piece shape offer an attractive system for studying the mechanisms underpinning cell morphogenesis in a plant tissue. The formation of the interdigitated lobes and indentations in these interlocking cells relies on the integration of chemical and mechanical signals and cell-to-cell signals to establish interdigitated polar sites defining lobes and indentations. Recent computational and experimental studies have suggested new roles of cell walls, their interplay with mechanical signals, cell polarity signaling regulated by auxin and brassinosteriods, and the cytoskeleton in the regulation of pavement cell morphogenesis. This review summarizes the current state of knowledge on these regulatory mechanisms behind pavement cell morphogenesis in plants and discusses how they could be integrated spatiotemporally to generate the interdigitated polarity patterns and the interlocking shape in pavement cells.
Collapse
Affiliation(s)
- Wenwei Lin
- Institute for Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - Zhenbiao Yang
- Institute for Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, USA.
| |
Collapse
|
12
|
Segado P, Heredia-Guerrero JA, Heredia A, Domínguez E. Cutinsomes and CUTIN SYNTHASE1 Function Sequentially in Tomato Fruit Cutin Deposition. PLANT PHYSIOLOGY 2020; 183:1622-1637. [PMID: 32457092 PMCID: PMC7401130 DOI: 10.1104/pp.20.00516] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 05/09/2020] [Indexed: 05/19/2023]
Abstract
The aerial parts of plants, including the leaves, fruits and non-lignified stems, are covered with a protective cuticle, largely composed of the polyester cutin. Two mechanisms of cutin deposition have been identified in tomato (Solanum lycopersicum) fruit. The contribution of each mechanism to cutin synthesis and deposition has shown a temporal and coordinated sequence that correlates with the two periods of organ growth, cell division and cell expansion. Cutinsomes, self-assembled particles composed of esterified cutin monomers, are involved in the synthesis of the procuticle during cell division and provide a template for further cutin deposition. CUTIN SYNTHASE1 (CUS1), an acyl transferase enzyme that links cutin monomers, contributes to massive cuticle deposition during the early stages of the cell expansion period by incorporating additional cutin to the procuticle template. However, cutin deposition and polymerization appear to be part of a more complex biological scenario, which is yet not fully understood. CUS1 is also associated with the coordinated growth of the cutinized and non-cutinized domains of the outer epidermal wall, and affects cell size. A dynamic and complex interplay linking cutin synthesis with cell wall development and epidermal cell size has been identified.
Collapse
Affiliation(s)
- Patricia Segado
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga - Consejo Superior de Investigaciones Científicas Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, E-29071 Málaga, Spain
| | - José Alejandro Heredia-Guerrero
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga - Consejo Superior de Investigaciones Científicas, Departamento de Mejora Genética y Biotecnología, Estación Experimental La Mayora, Algarrobo-Costa, E-29750 Málaga, Spain
| | - Antonio Heredia
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga - Consejo Superior de Investigaciones Científicas Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, E-29071 Málaga, Spain
| | - Eva Domínguez
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga - Consejo Superior de Investigaciones Científicas, Departamento de Mejora Genética y Biotecnología, Estación Experimental La Mayora, Algarrobo-Costa, E-29750 Málaga, Spain
| |
Collapse
|
13
|
Kutschera U, Khanna R. Auxin action in developing maize coleoptiles: challenges and open questions. PLANT SIGNALING & BEHAVIOR 2020; 15:1762327. [PMID: 32403974 PMCID: PMC8570730 DOI: 10.1080/15592324.2020.1762327] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 04/24/2020] [Accepted: 04/26/2020] [Indexed: 06/11/2023]
Abstract
The year 2020 marks the 150th anniversary of the elucidation of the process of plant organ growth at the cellular level by Julius Sachs (1870). In this Addendum to a Review Article in Molecular Plant, we describe this fundamental discovery and argue that the etiolated grass coleoptile still represents the system of choice for the experimental analysis of auxin (indole-3-acetic acid, IAA)-action. With reference to the phenomenon of 'tissue tension', we discuss the acid-growth hypotheses of IAA-induced wall loosening and the process of vacuolar expansion, respectively. IAA-mediated elongation appears to be independent of wall acidification, and may be regulated via the secretion of glycoproteins into the outer epidermal wall, whereby turgor (and tissue) pressure provides the 'driving force' for growth. As predicted by the "acid growth-hypothesis", the fungal phytotoxin Fusicoccin (Fc) induces organ elongation via the rapid secretion of protons. We conclude that "cell elongation" can only be understood at the level of the entire organ that displays biomechanical features not established by single cells. This systems-level approach can be traced back to the work of Sachs (1870).
Collapse
Affiliation(s)
- Ulrich Kutschera
- I-Cultiver, Inc., San Francisco, CA, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Rajnish Khanna
- I-Cultiver, Inc., San Francisco, CA, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| |
Collapse
|
14
|
Xin X, Lei L, Zheng Y, Zhang T, Pingali SV, O’Neill H, Cosgrove DJ, Li S, Gu Y. Cellulose synthase interactive1- and microtubule-dependent cell wall architecture is required for acid growth in Arabidopsis hypocotyls. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:2982-2994. [PMID: 32016356 PMCID: PMC7260726 DOI: 10.1093/jxb/eraa063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 02/02/2020] [Indexed: 05/02/2023]
Abstract
Auxin-induced cell elongation relies in part on the acidification of the cell wall, a process known as acid growth that presumably triggers expansin-mediated wall loosening via altered interactions between cellulose microfibrils. Cellulose microfibrils are a major determinant for anisotropic growth and they provide the scaffold for cell wall assembly. Little is known about how acid growth depends on cell wall architecture. To explore the relationship between acid growth-mediated cell elongation and plant cell wall architecture, two mutants (jia1-1 and csi1-3) that are defective in cellulose biosynthesis and cellulose microfibril organization were analyzed. The study revealed that cell elongation is dependent on CSI1-mediated cell wall architecture but not on the overall crystalline cellulose content. We observed a correlation between loss of crossed-polylamellate walls and loss of auxin- and fusicoccin-induced cell growth in csi1-3. Furthermore, induced loss of crossed-polylamellate walls via disruption of cortical microtubules mimics the effect of csi1 in acid growth. We hypothesize that CSI1- and microtubule-dependent crossed-polylamellate walls are required for acid growth in Arabidopsis hypocotyls.
Collapse
Affiliation(s)
- Xiaoran Xin
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Lei Lei
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Yunzhen Zheng
- Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Tian Zhang
- Department of Biology, Pennsylvania State University, University Park, PA, USA
| | | | - Hugh O’Neill
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Daniel J Cosgrove
- Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Shundai Li
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Ying Gu
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| |
Collapse
|
15
|
Zhang T, Tang H, Vavylonis D, Cosgrove DJ. Disentangling loosening from softening: insights into primary cell wall structure. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:1101-1117. [PMID: 31469935 DOI: 10.1111/tpj.14519] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/08/2019] [Accepted: 08/19/2019] [Indexed: 05/13/2023]
Abstract
How cell wall elasticity, plasticity, and time-dependent extension (creep) relate to one another, to plant cell wall structure and to cell growth remain unsettled topics. To examine these issues without the complexities of living tissues, we treated cell-free strips of onion epidermal walls with various enzymes and other agents to assess which polysaccharides bear mechanical forces in-plane and out-of-plane of the cell wall. This information is critical for integrating concepts of wall structure, wall material properties, tissue mechanics and mechanisms of cell growth. With atomic force microscopy we also monitored real-time changes in the wall surface during treatments. Driselase, a potent cocktail of wall-degrading enzymes, removed cellulose microfibrils in superficial lamellae sequentially, layer-by-layer, and softened the wall (reduced its mechanical stiffness), yet did not induce wall loosening (creep). In contrast Cel12A, a bifunctional xyloglucanase/cellulase, induced creep with only subtle changes in wall appearance. Both Driselase and Cel12A increased the tensile compliance, but differently for elastic and plastic components. Homogalacturonan solubilization by pectate lyase and calcium chelation greatly increased the indentation compliance without changing tensile compliances. Acidic buffer induced rapid cell wall creep via endogenous α-expansins, with negligible effects on wall compliances. We conclude that these various wall properties are not tightly coupled and therefore reflect distinctive aspects of wall structure. Cross-lamellate networks of cellulose microfibrils influenced creep and tensile stiffness whereas homogalacturonan influenced indentation mechanics. This information is crucial for constructing realistic molecular models that define how wall mechanics and growth depend on primary cell wall structure.
Collapse
Affiliation(s)
- Tian Zhang
- Department of Biology and Center for Lignocellulose Structure and Formation, 208 Mueller Laboratory, Pennsylvania State University, University Park, State College, Pennsylvania, 16802, USA
| | - Haosu Tang
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania, 18015, USA
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania, 18015, USA
| | - Daniel J Cosgrove
- Department of Biology and Center for Lignocellulose Structure and Formation, 208 Mueller Laboratory, Pennsylvania State University, University Park, State College, Pennsylvania, 16802, USA
| |
Collapse
|
16
|
Wong JH, Kato T, Belteton SA, Shimizu R, Kinoshita N, Higaki T, Sakumura Y, Szymanski DB, Hashimoto T. Basic Proline-Rich Protein-Mediated Microtubules Are Essential for Lobe Growth and Flattened Cell Geometry. PLANT PHYSIOLOGY 2019; 181:1535-1551. [PMID: 31601644 PMCID: PMC6878025 DOI: 10.1104/pp.19.00811] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/30/2019] [Indexed: 05/09/2023]
Abstract
Complex cell shapes are generated first by breaking symmetry, and subsequent polar growth. Localized bending of anticlinal walls initiates lobe formation in the epidermal pavement cells of cotyledons and leaves, but how the microtubule cytoskeleton mediates local cell growth, and how plant pavement cells benefit from adopting jigsaw puzzle-like shapes, are poorly understood. In Arabidopsis (Arabidopsis thaliana), the basic Pro-rich protein (BPP) microtubule-associated protein family comprises seven members. We analyzed lobe morphogenesis in cotyledon pavement cells of a BPP1;BPP2;BPP5 triple knockout mutant. New image analysis methods (MtCurv and BQuant) showed that anticlinal microtubule bundles were significantly reduced and cortical microtubules that fan out radially across the periclinal wall did not enrich at the convex side of developing lobes. Despite these microtubule defects, new lobes were initiated at the same frequency as in wild-type cells, but they did not expand into well-defined protrusions. Eventually, mutant cells formed nearly polygonal shapes and adopted concentric microtubule patterns. The mutant periclinal cell wall bulged outward. The radius of the calculated inscribed circle of the pavement cells, a proposed proxy for maximal stress in the cell wall, was consistently larger in the mutant cells during cotyledon development, and correlated with an increase in cell height. These bpp mutant phenotypes provide genetic and cell biological evidence that initiation and growth of lobes are distinct morphogenetic processes, and that interdigitated cell geometry effectively suppresses large outward bulging of pavement cells.
Collapse
Affiliation(s)
- Jeh Haur Wong
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Takehide Kato
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Samuel A Belteton
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Rie Shimizu
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Nene Kinoshita
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Takumi Higaki
- International Research Organization for Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
| | - Yuichi Sakumura
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Daniel B Szymanski
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
| | - Takashi Hashimoto
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| |
Collapse
|
17
|
Chen D, Melton LD, McGillivray DJ, Ryan TM, Harris PJ. Changes in the orientations of cellulose microfibrils during the development of collenchyma cell walls of celery (Apium graveolens L.). PLANTA 2019; 250:1819-1832. [PMID: 31463558 DOI: 10.1007/s00425-019-03262-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 08/14/2019] [Indexed: 06/10/2023]
Abstract
During development, cellulose microfibrils in collenchyma walls become increasingly longitudinal, as determined by small-angle X-ray scattering, despite the walls maintaining a fine structure indicative of a crossed-polylamellate structure. Collenchyma cells have thickened primary cell walls and provide mechanical support during plant growth. During their development, these cells elongate and their walls thicken considerably. We used microscopy and synchrotron small-angle X-ray scattering to study changes in the orientations of cellulose microfibrils that occur during development in the walls of collenchyma cells present in peripheral strands in celery (Apium graveolens) petioles. Transmission electron microscopy showed that the walls consisted of many lamellae (polylamellate), with lamellae containing longitudinally oriented cellulose microfibrils alternating with microfibrils oriented at higher angles. The lamellae containing longitudinally oriented microfibrils predominated at later stages of development. Nevertheless, transmission electron microscopy of specially stained, oblique sections provided evidence that the cellulose microfibrils were ordered throughout development as crossed-polylamellate structures. These results are consistent with our synchrotron small-angle X-ray scattering results that showed the cellulose microfibrils become oriented increasingly longitudinally during development. Some passive reorientation of cellulose microfibrils may occur during development, but extensive reorientation throughout the wall would destroy ordered structures. Atomic force microscopy and field emission scanning electron microscopy were used to determine the orientations of newly deposited cellulose microfibrils. These were found to vary widely among different cells, which could be consistent with the formation of crossed-polylamellate structures. These newly deposited cellulose microfibrils are deposited in a layer of pectic polysaccharides that lies immediately outside the plasma membrane. Overall, our results show that during development of collenchyma walls, the cellulose microfibrils become increasingly longitudinal in orientation, yet organized, crossed-polylamellate structures are maintained.
Collapse
Affiliation(s)
- Da Chen
- School of Chemical Sciences, The University of Auckland, Auckland Mail Centre, Private Bag 92019, Auckland, 1142, New Zealand
- Department of Food Science, Purdue University, 745 Agriculture Mall Drive, West Lafayette, IN, 47907, USA
| | - Laurence D Melton
- School of Chemical Sciences, The University of Auckland, Auckland Mail Centre, Private Bag 92019, Auckland, 1142, New Zealand
| | - Duncan J McGillivray
- School of Chemical Sciences, The University of Auckland, Auckland Mail Centre, Private Bag 92019, Auckland, 1142, New Zealand
- The MacDiarmid Institute, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand
| | - Timothy M Ryan
- The MacDiarmid Institute, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand
- The Australian Synchrotron, 800 Blackburn Rd, Clayton, VIC, 3168, Australia
| | - Philip J Harris
- School of Biological Sciences, The University of Auckland, Auckland Mail Centre, Private Bag 92019, Auckland, 1142, New Zealand.
| |
Collapse
|
18
|
Uchida N, Torii KU. Stem cells within the shoot apical meristem: identity, arrangement and communication. Cell Mol Life Sci 2019; 76:1067-1080. [PMID: 30523363 PMCID: PMC11105333 DOI: 10.1007/s00018-018-2980-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/06/2018] [Accepted: 11/26/2018] [Indexed: 10/27/2022]
Abstract
Stem cells are specific cells that renew themselves and also provide daughter cells for organ formation. In plants, primary stem cell populations are nurtured within shoot and root apical meristems (SAM and RAM) for the production of aerial and underground parts, respectively. This review article summarizes recent progress on control of stem cells in the SAM from studies of the model plant Arabidopsis thaliana. To that end, a brief overview of the RAM is provided first to emphasize similarities and differences between the two apical meristems, which would help in better understanding of stem cells in the SAM. Subsequently, we will discuss in depth how stem cells are arranged in an organized manner in the SAM, how dynamically the stem cell identity is regulated, what factors participate in stem cell control, and how intercellular communication by mobile signals modulates stem cell behaviors within the SAM. Remaining questions and perspectives are also presented for future studies.
Collapse
Affiliation(s)
- Naoyuki Uchida
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.
| | - Keiko U Torii
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA
| |
Collapse
|
19
|
Rudall PJ, Bateman RM. Leaf surface development and the plant fossil record: stomatal patterning in Bennettitales. Biol Rev Camb Philos Soc 2019; 94:1179-1194. [DOI: 10.1111/brv.12497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 11/28/2022]
|
20
|
Bou Daher F, Chen Y, Bozorg B, Clough J, Jönsson H, Braybrook SA. Anisotropic growth is achieved through the additive mechanical effect of material anisotropy and elastic asymmetry. eLife 2018; 7:e38161. [PMID: 30226465 PMCID: PMC6143341 DOI: 10.7554/elife.38161] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/28/2018] [Indexed: 11/13/2022] Open
Abstract
Fast directional growth is a necessity for the young seedling; after germination, it needs to quickly penetrate the soil to begin its autotrophic life. In most dicot plants, this rapid escape is due to the anisotropic elongation of the hypocotyl, the columnar organ between the root and the shoot meristems. Anisotropic growth is common in plant organs and is canonically attributed to cell wall anisotropy produced by oriented cellulose fibers. Recently, a mechanism based on asymmetric pectin-based cell wall elasticity has been proposed. Here we present a harmonizing model for anisotropic growth control in the dark-grown Arabidopsis thaliana hypocotyl: basic anisotropic information is provided by cellulose orientation) and additive anisotropic information is provided by pectin-based elastic asymmetry in the epidermis. We quantitatively show that hypocotyl elongation is anisotropic starting at germination. We present experimental evidence for pectin biochemical differences and wall mechanics providing important growth regulation in the hypocotyl. Lastly, our in silico modelling experiments indicate an additive collaboration between pectin biochemistry and cellulose orientation in promoting anisotropic growth.
Collapse
Affiliation(s)
- Firas Bou Daher
- Department of Molecular, Cell and Developmental BiologyUniversity of California, Los AngelesLos AngelesUnited States
- The Sainsbury LaboratoryUniversity of CambridgeCambridgeUnited Kingdom
| | - Yuanjie Chen
- The Sainsbury LaboratoryUniversity of CambridgeCambridgeUnited Kingdom
| | - Behruz Bozorg
- The Sainsbury LaboratoryUniversity of CambridgeCambridgeUnited Kingdom
- Computational Biology and Biological Physics GroupLund UniversityLundSweden
| | - Jack Clough
- The Sainsbury LaboratoryUniversity of CambridgeCambridgeUnited Kingdom
| | - Henrik Jönsson
- The Sainsbury LaboratoryUniversity of CambridgeCambridgeUnited Kingdom
- Computational Biology and Biological Physics GroupLund UniversityLundSweden
- Department of Applied Mathematics and Theoretical PhysicsUniversity of CambridgeCambridgeUnited Kingdom
| | - Siobhan A Braybrook
- Department of Molecular, Cell and Developmental BiologyUniversity of California, Los AngelesLos AngelesUnited States
- The Sainsbury LaboratoryUniversity of CambridgeCambridgeUnited Kingdom
- Molecular Biology InstituteUniversity of California, Los AngelesLos AngelesUnited States
| |
Collapse
|
21
|
Ye D, Kiemle SN, Rongpipi S, Wang X, Wang C, Cosgrove DJ, Gomez EW, Gomez ED. Resonant soft X-ray scattering reveals cellulose microfibril spacing in plant primary cell walls. Sci Rep 2018; 8:12449. [PMID: 30127533 PMCID: PMC6102304 DOI: 10.1038/s41598-018-31024-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 08/10/2018] [Indexed: 12/22/2022] Open
Abstract
Cellulose microfibrils are crucial for many of the remarkable mechanical properties of primary cell walls. Nevertheless, many structural features of cellulose microfibril organization in cell walls are not yet fully described. Microscopy techniques provide direct visualization of cell wall organization, and quantification of some aspects of wall microstructure is possible through image processing. Complementary to microscopy techniques, scattering yields structural information in reciprocal space over large sample areas. Using the onion epidermal wall as a model system, we introduce resonant soft X-ray scattering (RSoXS) to directly quantify the average interfibril spacing. Tuning the X-ray energy to the calcium L-edge enhances the contrast between cellulose and pectin due to the localization of calcium ions to homogalacturonan in the pectin matrix. As a consequence, RSoXS profiles reveal an average center-to-center distance between cellulose microfibrils or microfibril bundles of about 20 nm.
Collapse
Affiliation(s)
- Dan Ye
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, United States
| | - Sarah N Kiemle
- Department of Biology, The Pennsylvania State University, University Park, PA, 16802, United States
| | - Sintu Rongpipi
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, United States
| | - Xuan Wang
- Department of Biology, The Pennsylvania State University, University Park, PA, 16802, United States
| | - Cheng Wang
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, United States
| | - Daniel J Cosgrove
- Department of Biology, The Pennsylvania State University, University Park, PA, 16802, United States
| | - Esther W Gomez
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, United States.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, United States.
| | - Enrique D Gomez
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, United States.
- Department of Materials Science and Engineering and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, United States.
| |
Collapse
|
22
|
Robinson S, Kuhlemeier C. Global Compression Reorients Cortical Microtubules in Arabidopsis Hypocotyl Epidermis and Promotes Growth. Curr Biol 2018; 28:1794-1802.e2. [DOI: 10.1016/j.cub.2018.04.028] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 01/22/2018] [Accepted: 04/09/2018] [Indexed: 12/17/2022]
|
23
|
Kutschera U, Niklas KJ. Julius Sachs (1868): The father of plant physiology. AMERICAN JOURNAL OF BOTANY 2018; 105:656-666. [PMID: 29772073 DOI: 10.1002/ajb2.1078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 01/31/2018] [Indexed: 05/10/2023]
Abstract
The year 2018 marks the 150th anniversary of the first publication of Julius von Sachs' (1832-1897) Lehrbuch der Botanik (Textbook of Botany), which provided a comprehensive summary of what was then known about the plant sciences. Three years earlier, in 1865, Sachs produced the equally impressive Handbuch der Experimental-Physiologie der Pflanzen (Handbook of Experimental Plant Physiology), which summarized the state of knowledge in all aspects of the discipline known today as plant physiology. Both of these books provided numerous insights based on Sachs' seminal experiments. By virtue of a reliance on detailed empirical observation and the rigorous application of chemical and physical principles, it is fair to say that the publication of these two monumental works marked the beginning of what can be called "modern-day" plant science. Moreover, Sachs' Lehrbuch der Botanik prefigured the ascendance of plant molecular biology and the systems biology of photoautotrophic organisms. Regrettably, many of the insights of this great scientist have been forgotten by the generations who followed. It is only fitting, therefore, that the anniversary of the publication of the Lehrbuch der Botanik and the career of "the father of plant physiology" should be honored and reviewed, particularly because Sachs established the physiology of green organisms as an integral branch of botany and incorporated a Darwinian perspective into plant biology. Here we highlight key insights, with particular emphasis on Sachs' detailed discussion of sexual reproduction at the cellular level and his endorsement of Darwinian evolution.
Collapse
Affiliation(s)
- Ulrich Kutschera
- Institute of Biology, University of Kassel, Heinrich-Plett-Str. 40, D-34132, Kassel, Germany
| | - Karl J Niklas
- Plant Science Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| |
Collapse
|
24
|
Zheng Y, Wang X, Chen Y, Wagner E, Cosgrove DJ. Xyloglucan in the primary cell wall: assessment by FESEM, selective enzyme digestions and nanogold affinity tags. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:211-226. [PMID: 29160933 DOI: 10.1111/tpj.13778] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/02/2017] [Accepted: 11/06/2017] [Indexed: 05/02/2023]
Abstract
Xyloglucan has been hypothesized to bind extensively to cellulose microfibril surfaces and to tether microfibrils into a load-bearing network, thereby playing a central role in wall mechanics and growth, but this view is challenged by newer results. Here we combined high-resolution imaging by field emission scanning electron microscopy (FESEM) with nanogold affinity tags and selective endoglucanase treatments to assess the spatial location and conformation of xyloglucan in onion cell walls. FESEM imaging of xyloglucanase-digested cell walls revealed an altered microfibril organization but did not yield clear evidence of xyloglucan conformations. Backscattered electron detection provided excellent detection of nanogold affinity tags in the context of wall fibrillar organization. Labelling with xyloglucan-specific CBM76 conjugated with nanogold showed that xyloglucans were associated with fibril surfaces in both extended and coiled conformations, but tethered configurations were not observed. Labelling with nanogold-conjugated CBM3, which binds the hydrophobic surface of crystalline cellulose, was infrequent until the wall was predigested with xyloglucanase, whereupon microfibril labelling was extensive. When tamarind xyloglucan was allowed to bind to xyloglucan-depleted onion walls, CBM76 labelling gave positive evidence for xyloglucans in both extended and coiled conformations, yet xyloglucan chains were not directly visible by FESEM. These results indicate that an appreciable, but still small, surface of cellulose microfibrils in the onion wall is tightly bound with extended xyloglucan chains and that some of the xyloglucan has a coiled conformation.
Collapse
Affiliation(s)
- Yunzhen Zheng
- Center for Lignocellulose Structure and Formation, Penn State University, University Park, PA, 16802, USA
- Department of Biology, Penn State University, University Park, PA, 16802, USA
| | - Xuan Wang
- Center for Lignocellulose Structure and Formation, Penn State University, University Park, PA, 16802, USA
- Department of Biology, Penn State University, University Park, PA, 16802, USA
| | - Yuning Chen
- Department of Biology, Penn State University, University Park, PA, 16802, USA
| | - Edward Wagner
- Department of Biology, Penn State University, University Park, PA, 16802, USA
| | - Daniel J Cosgrove
- Center for Lignocellulose Structure and Formation, Penn State University, University Park, PA, 16802, USA
- Department of Biology, Penn State University, University Park, PA, 16802, USA
| |
Collapse
|
25
|
Xia X, Zhang HM, Offler CE, Patrick JW. A Structurally Specialized Uniform Wall Layer is Essential for Constructing Wall Ingrowth Papillae in Transfer Cells. FRONTIERS IN PLANT SCIENCE 2017; 8:2035. [PMID: 29259611 PMCID: PMC5723425 DOI: 10.3389/fpls.2017.02035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 11/14/2017] [Indexed: 05/29/2023]
Abstract
Transfer cells are characterized by wall labyrinths with either a flange or reticulate architecture. A literature survey established that reticulate wall ingrowth papillae ubiquitously arise from a modified component of their wall labyrinth, termed the uniform wall layer; a structure absent from flange transfer cells. This finding sparked an investigation of the deposition characteristics and role of the uniform wall layer using a Vicia faba cotyledon culture system. On transfer of cotyledons to culture, their adaxial epidermal cells spontaneously trans-differentiate to a reticulate architecture comparable to their abaxial epidermal transfer cell counterparts formed in planta. Uniform wall layer construction commenced once adaxial epidermal cell expansion had ceased to overlay the original outer periclinal wall on its inner surface. In contrast to the dense ring-like lattice of cellulose microfibrils in the original primary wall, the uniform wall layer was characterized by a sparsely dispersed array of linear cellulose microfibrils. A re-modeled cortical microtubule array exerted no influence on uniform wall layer formation or on its cellulose microfibril organization. Surprisingly, formation of the uniform wall layer was not dependent upon depositing a cellulose scaffold. In contrast, uniform wall cellulose microfibrils were essential precursors for constructing wall ingrowth papillae. On converging to form wall ingrowth papillae, the cellulose microfibril diameters increased 3-fold. This event correlated with up-regulated differential, and transfer-cell specific, expression of VfCesA3B while transcript levels of other cellulose biosynthetic-related genes linked with primary wall construction were substantially down-regulated.
Collapse
|
26
|
Möller B, Poeschl Y, Plötner R, Bürstenbinder K. PaCeQuant: A Tool for High-Throughput Quantification of Pavement Cell Shape Characteristics. PLANT PHYSIOLOGY 2017; 175:998-1017. [PMID: 28931626 PMCID: PMC5664455 DOI: 10.1104/pp.17.00961] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/17/2017] [Indexed: 05/05/2023]
Abstract
Pavement cells (PCs) are the most frequently occurring cell type in the leaf epidermis and play important roles in leaf growth and function. In many plant species, PCs form highly complex jigsaw-puzzle-shaped cells with interlocking lobes. Understanding of their development is of high interest for plant science research because of their importance for leaf growth and hence for plant fitness and crop yield. Studies of PC development, however, are limited, because robust methods are lacking that enable automatic segmentation and quantification of PC shape parameters suitable to reflect their cellular complexity. Here, we present our new ImageJ-based tool, PaCeQuant, which provides a fully automatic image analysis workflow for PC shape quantification. PaCeQuant automatically detects cell boundaries of PCs from confocal input images and enables manual correction of automatic segmentation results or direct import of manually segmented cells. PaCeQuant simultaneously extracts 27 shape features that include global, contour-based, skeleton-based, and PC-specific object descriptors. In addition, we included a method for classification and analysis of lobes at two-cell junctions and three-cell junctions, respectively. We provide an R script for graphical visualization and statistical analysis. We validated PaCeQuant by extensive comparative analysis to manual segmentation and existing quantification tools and demonstrated its usability to analyze PC shape characteristics during development and between different genotypes. PaCeQuant thus provides a platform for robust, efficient, and reproducible quantitative analysis of PC shape characteristics that can easily be applied to study PC development in large data sets.
Collapse
Affiliation(s)
- Birgit Möller
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Yvonne Poeschl
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
- German Integrative Research Center for Biodiversity (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany
| | - Romina Plötner
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Katharina Bürstenbinder
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| |
Collapse
|
27
|
Abstract
Liquid crystals play an important role in biology because the combination of order and mobility is a basic requirement for self-organisation and structure formation in living systems. Cholesteric liquid crystals are omnipresent in living matter under both in vivo and in vitro conditions and address the major types of molecules essential to life. In the animal and plant kingdoms, the cholesteric structure is a recurring design, suggesting a convergent evolution to an optimised left-handed helix. Herein, we review the recent advances in the cholesteric organisation of DNA, chromatin, chitin, cellulose, collagen, viruses, silk and cholesterol ester deposition in atherosclerosis. Cholesteric structures can be found in bacteriophages, archaea, eukaryotes, bacterial nucleoids, chromosomes of unicellular algae, sperm nuclei of many vertebrates, cuticles of crustaceans and insects, bone, tendon, cornea, fish scales and scutes, cuttlebone and squid pens, plant cell walls, virus suspensions, silk produced by spiders and silkworms, and arterial wall lesions. This article specifically aims at describing the consequences of the cholesteric geometry in living matter, which are far from being fully defined and understood, and discusses various perspectives. The roles and functions of biological cholesteric liquid crystals include maximisation of packing efficiency, morphogenesis, mechanical stability, optical information, radiation protection and evolution pressure.
Collapse
Affiliation(s)
- Michel Mitov
- Centre d'Elaboration de Matériaux et d'Etudes Structurales (CEMES), CNRS, BP 94347, 29 rue Jeanne-Marvig, F-31055 Toulouse Cedex 4, France.
| |
Collapse
|
28
|
Segado P, Domínguez E, Heredia A. Ultrastructure of the Epidermal Cell Wall and Cuticle of Tomato Fruit (Solanum lycopersicum L.) during Development. PLANT PHYSIOLOGY 2016; 170:935-46. [PMID: 26668335 PMCID: PMC4734585 DOI: 10.1104/pp.15.01725] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/08/2015] [Indexed: 05/20/2023]
Abstract
The epidermis plays a pivotal role in plant development and interaction with the environment. However, it is still poorly understood, especially its outer epidermal wall: a singular wall covered by a cuticle. Changes in the cuticle and cell wall structures are important to fully understand their functions. In this work, an ultrastructure and immunocytochemical approach was taken to identify changes in the cuticle and the main components of the epidermal cell wall during tomato fruit development. A thin and uniform procuticle was already present before fruit set. During cell division, the inner side of the procuticle showed a globular structure with vesicle-like particles in the cell wall close to the cuticle. Transition between cell division and elongation was accompanied by a dramatic increase in cuticle thickness, which represented more than half of the outer epidermal wall, and the lamellate arrangement of the non-cutinized cell wall. Changes in this non-cutinized outer wall during development showed specific features not shared with other cell walls. The coordinated nature of the changes observed in the cuticle and the epidermal cell wall indicate a deep interaction between these two supramolecular structures. Hence, the cuticle should be interpreted within the context of the outer epidermal wall.
Collapse
Affiliation(s)
- Patricia Segado
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga - Consejo Superior de Investigaciones Científicas, Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, E-29071 Málaga, Spain (P.S., A.H.); andDepartamento de Mejora Genética y Biotecnología, Estación Experimental La Mayora, Algarrobo-Costa, E-29750 Málaga, Spain. (E.D.)
| | - Eva Domínguez
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga - Consejo Superior de Investigaciones Científicas, Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, E-29071 Málaga, Spain (P.S., A.H.); andDepartamento de Mejora Genética y Biotecnología, Estación Experimental La Mayora, Algarrobo-Costa, E-29750 Málaga, Spain. (E.D.)
| | - Antonio Heredia
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga - Consejo Superior de Investigaciones Científicas, Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, E-29071 Málaga, Spain (P.S., A.H.); andDepartamento de Mejora Genética y Biotecnología, Estación Experimental La Mayora, Algarrobo-Costa, E-29750 Málaga, Spain. (E.D.)
| |
Collapse
|
29
|
Youssef C, Aubry C, Montrichard F, Beucher D, Juchaux M, Ben C, Prosperi JM, Teulat B. Cell length instead of cell number becomes the predominant factor contributing to hypocotyl length genotypic differences under abiotic stress in Medicago truncatula. PHYSIOLOGIA PLANTARUM 2016; 156:108-124. [PMID: 26303328 DOI: 10.1111/ppl.12379] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/19/2015] [Accepted: 06/18/2015] [Indexed: 06/04/2023]
Abstract
Hypocotyl elongation in the dark is a crucial process to ensure seedling emergence. It relies both on the cell number and cell length. The contribution of these two factors to the maximal hypocotyl length and the impact of environmental conditions on this contribution are not known. This is surprising considering the agronomic and economical importance of seedling emergence in crop establishment. Using 14 genotypes from a nested core collection representing Medicago truncatula (barrel medic) natural variation, we investigated how epidermal cell number and cell length contribute to hypocotyl length under optimal, low temperature (8°C) and water deficit (-0.50 MPa) conditions. Both cell number and length vary according to genotypes and contribute to maximal hypocotyl length differences between genotypes. This contribution, however, depends on growth conditions. Cell number is the major contributor under optimal conditions (60%) whereas cell length becomes the major determinant under stress. Maximal hypocotyl length is correlated with hypocotyl elongation rate under both stresses but not under optimal condition, revealing contrasted genotypes for cell elongation capacity under stress. To identify the genetic regulators determining cell number and cell length, quantitative trait loci (QTLs) were detected using a recombinant inbred lines population exhibiting segregation in maximal hypocotyl length. Two QTLs controlling cell number and three QTLs controlling cell length at low temperature were detected. One QTL for cell number and two for cell length were found to be associated with hypocotyl length under low temperature. This study provides new information to improve seedling emergence under abiotic stress.
Collapse
Affiliation(s)
- Chvan Youssef
- Institut de Recherche en Horticulture et Semences (UMR 1345 IRHS), Agrocampus Ouest, SFR 4207 QuaSaV, Beaucouzé Cedex, France
| | - Catherine Aubry
- Institut de Recherche en Horticulture et Semences (UMR 1345 IRHS), Université d'Angers, SFR 4207 QuaSaV, Beaucouzé Cedex, France
| | - Françoise Montrichard
- Institut de Recherche en Horticulture et Semences (UMR 1345 IRHS), Université d'Angers, SFR 4207 QuaSaV, Beaucouzé Cedex, France
| | - Daniel Beucher
- Institut de Recherche en Horticulture et Semences (UMR 1345 IRHS), Agrocampus Ouest, SFR 4207 QuaSaV, Beaucouzé Cedex, France
| | | | - Cécile Ben
- Laboratoire Ecologie Fonctionnelle et Environnement (UMR 5245, EcoLab), Université de Toulouse, INP, UPS, ENSAT, Castanet Tolosan, France
- Laboratoire Ecologie Fonctionnelle et Environnement (UMR 5245, EcoLab), CNRS, Castanet Tolosan, France
| | - Jean-Marie Prosperi
- Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales (UMR 1334 AGAP), INRA, Montpellier, France
| | - Béatrice Teulat
- Institut de Recherche en Horticulture et Semences (UMR 1345 IRHS), Agrocampus Ouest, SFR 4207 QuaSaV, Beaucouzé Cedex, France
| |
Collapse
|
30
|
Kutschera U, Wang ZY. Growth-limiting proteins in maize coleoptiles and the auxin-brassinosteroid hypothesis of mesocotyl elongation. PROTOPLASMA 2016; 253:3-14. [PMID: 25772679 PMCID: PMC6609159 DOI: 10.1007/s00709-015-0787-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/27/2015] [Indexed: 05/08/2023]
Abstract
The shoot of grass coleoptiles consists of the mesocotyl, the node, and the coleoptile (with enclosed primary leaf). Since the 1930s, it is known that auxin (indole-3-acetic acid, IAA), produced in the tip of the coleoptile, is the central regulator of turgor-driven organ growth. Fifty years ago, it was discovered that antibiotics that suppress protein biosynthesis, such as cycloheximide, inhibit auxin (IAA)-induced cell elongation in excised sections of coleoptiles and stems. Based on such inhibitor studies, the concept of "growth-limiting proteins (GLPs)" emerged that was subsequently elaborated and modified. Here, we summarize the history of this idea with reference to IAA-mediated shoot elongation in maize (Zea mays) seedlings and recent studies on the molecular mechanism underlying auxin action in Arabidopsis thaliana. In addition, the analysis of light-induced inhibition of shoot elongation in intact corn seedlings is discussed. We propose a concept to account for the GLP-mediated epidermal wall-loosening process in coleoptile segments and present a more general model of growth regulation in intact maize seedlings. Quantitative proteomic and genomic studies led to a refinement of the classic "GLP concept" to explain phytohormone-mediated cell elongation at the molecular level (i.e., the recently proposed theory of a "central growth regulation network," CGRN). Novel data show that mesocotyl elongation not only depends on auxin but also on brassinosteroids (BRs). However, the biochemical key processes that regulate the IAA/BR-mediated loosening of the expansion-limiting epidermal wall(s) have not yet been elucidated.
Collapse
Affiliation(s)
- Ulrich Kutschera
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA.
| | - Zhi-Yong Wang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| |
Collapse
|
31
|
Zhang T, Zheng Y, Cosgrove DJ. Spatial organization of cellulose microfibrils and matrix polysaccharides in primary plant cell walls as imaged by multichannel atomic force microscopy. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:179-92. [PMID: 26676644 DOI: 10.1111/tpj.13102] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/20/2015] [Accepted: 11/27/2015] [Indexed: 05/02/2023]
Abstract
We used atomic force microscopy (AFM), complemented with electron microscopy, to characterize the nanoscale and mesoscale structure of the outer (periclinal) cell wall of onion scale epidermis - a model system for relating wall structure to cell wall mechanics. The epidermal wall contains ~100 lamellae, each ~40 nm thick, containing 3.5-nm wide cellulose microfibrils oriented in a common direction within a lamella but varying by ~30 to 90° between adjacent lamellae. The wall thus has a crossed polylamellate, not helicoidal, wall structure. Montages of high-resolution AFM images of the newly deposited wall surface showed that single microfibrils merge into and out of short regions of microfibril bundles, thereby forming a reticulated network. Microfibril direction within a lamella did not change gradually or abruptly across the whole face of the cell, indicating continuity of the lamella across the outer wall. A layer of pectin at the wall surface obscured the underlying cellulose microfibrils when imaged by FESEM, but not by AFM. The AFM thus preferentially detects cellulose microfibrils by probing through the soft matrix in these hydrated walls. AFM-based nanomechanical maps revealed significant heterogeneity in cell wall stiffness and adhesiveness at the nm scale. By color coding and merging these maps, the spatial distribution of soft and rigid matrix polymers could be visualized in the context of the stiffer microfibrils. Without chemical extraction and dehydration, our results provide multiscale structural details of the primary cell wall in its near-native state, with implications for microfibrils motions in different lamellae during uniaxial and biaxial extensions.
Collapse
Affiliation(s)
- Tian Zhang
- Department of Biology and Center for Lignocellulose Structure and Formation, Penn State University, 208 Mueller Laboratory, University Park, PA, 16802, USA
| | - Yunzhen Zheng
- Department of Biology and Center for Lignocellulose Structure and Formation, Penn State University, 208 Mueller Laboratory, University Park, PA, 16802, USA
| | - Daniel J Cosgrove
- Department of Biology and Center for Lignocellulose Structure and Formation, Penn State University, 208 Mueller Laboratory, University Park, PA, 16802, USA
| |
Collapse
|
32
|
Kutschera U, Briggs WR. Phototropic solar tracking in sunflower plants: an integrative perspective. ANNALS OF BOTANY 2016; 117:1-8. [PMID: 26420201 PMCID: PMC4701145 DOI: 10.1093/aob/mcv141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 07/30/2015] [Indexed: 05/04/2023]
Abstract
BACKGROUND One of the best-known plant movements, phototropic solar tracking in sunflower (Helianthus annuus), has not yet been fully characterized. Two questions are still a matter of debate. (1) Is the adaptive significance solely an optimization of photosynthesis via the exposure of the leaves to the sun? (2) Is shade avoidance involved in this process? In this study, these concepts are discussed from a historical perspective and novel insights are provided. SCOPE AND METHODS Results from the primary literature on heliotropic growth movements led to the conclusion that these responses cease before anthesis, so that the flowering heads point to the East. Based on observations on 10-week-old plants, the diurnal East-West oscillations of the upper fifth of the growing stem and leaves in relation to the position of the sun (inclusive of nocturnal re-orientation) were documented, and photon fluence rates on the leaf surfaces on clear, cloudy and rainy days were determined. In addition, the light-response curve of net CO2 assimilation was determined on the upper leaves of the same batch of plants, and evidence for the occurrence of shade-avoidance responses in growing sunflower plants is summarized. CONCLUSIONS Only elongating, vegetative sunflower shoots and the upper leaves perform phototropic solar tracking. Photon fluence response and CO2 assimilation measurements cast doubt on the 'photosynthesis-optimization hypothesis' as the sole explanation for the evolution of these plant movements. We suggest that the shade-avoidance response, which maximizes light-driven CO2 assimilation, plays a major role in solar tracking populations of competing sunflower plants, and an integrative scheme of these growth movements is provided.
Collapse
Affiliation(s)
- Ulrich Kutschera
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Winslow R Briggs
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| |
Collapse
|
33
|
Jensen OE, Fozard JA. Multiscale models in the biomechanics of plant growth. Physiology (Bethesda) 2015; 30:159-66. [PMID: 25729061 DOI: 10.1152/physiol.00030.2014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Plant growth occurs through the coordinated expansion of tightly adherent cells, driven by regulated softening of cell walls. It is an intrinsically multiscale process, with the integrated properties of multiple cell walls shaping the whole tissue. Multiscale models encode physical relationships to bring new understanding to plant physiology and development.
Collapse
Affiliation(s)
- Oliver E Jensen
- School of Mathematics, University of Manchester, Manchester, United Kingdom; and
| | - John A Fozard
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington, United Kingdom
| |
Collapse
|
34
|
Zörb C, Mühling KH, Kutschera U, Geilfus CM. Salinity stiffens the epidermal cell walls of salt-stressed maize leaves: is the epidermis growth-restricting? PLoS One 2015; 10:e0118406. [PMID: 25760715 PMCID: PMC4356557 DOI: 10.1371/journal.pone.0118406] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 01/15/2015] [Indexed: 01/19/2023] Open
Abstract
As a result of salt (NaCl)-stress, sensitive varieties of maize (Zea mays L.) respond with a strong inhibition of organ growth. The reduction of leaf elongation investigated here has several causes, including a modification of the mechanical properties of the cell wall. Among the various tissues that form the leaf, the epidermis plays a special role in controlling organ growth, because it is thought to form a rigid outer leaf coat that can restrict elongation by interacting with the inner cell layers. This study was designed to determine whether growth-related changes in the leaf epidermis and its cell wall correspond to the overall reduction in cell expansion of maize leaves during an osmotic stress-phase induced by salt treatment. Two different maize varieties contrasting in their degree of salt resistance (i.e., the hybrids Lector vs. SR03) were compared in order to identify physiological features contributing to resistance towards salinity. Wall loosening-related parameters, such as the capacity of the epidermal cell wall to expand, β-expansin abundance and apoplastic pH values, were analysed. Our data demonstrate that, in the salt-tolerant maize hybrid which maintained leaf growth under salinity, the epidermal cell wall was more extensible under salt stress. This was associated with a shift of the epidermal apoplastic pH into a range more favourable for acid growth. The more sensitive hybrid that displayed a pronounced leaf growth-reduction was shown to have stiffer epidermal cell walls under stress. This may be attributable to the reduced abundance of cell wall-loosening β-expansin proteins following a high salinity-treatment in the nutrient solution (100 mM NaCl, 8 days). This study clearly documents that salt stress impairs epidermal wall-loosening in growth-reduced maize leaves.
Collapse
Affiliation(s)
- Christian Zörb
- Institute of Crop Science, Quality of Plant Products, University of Hohenheim, Stuttgart, Germany
| | - Karl H. Mühling
- Institute of Plant Nutrition and Soil Science, Christian-Albrechts-University Kiel, Kiel, Germany
| | | | - Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Christian-Albrechts-University Kiel, Kiel, Germany
| |
Collapse
|
35
|
Application of X-ray and neutron small angle scattering techniques to study the hierarchical structure of plant cell walls: a review. Carbohydr Polym 2015; 125:120-34. [PMID: 25857967 DOI: 10.1016/j.carbpol.2015.02.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/06/2015] [Accepted: 02/09/2015] [Indexed: 11/23/2022]
Abstract
Plant cell walls present an extremely complex structure of hierarchically assembled cellulose microfibrils embedded in a multi-component matrix. The biosynthesis process determines the mechanism of cellulose crystallisation and assembly, as well as the interaction of cellulose with other cell wall components. Thus, a knowledge of cellulose microfibril and bundle architecture, and the structural role of matrix components, is crucial for understanding cell wall functional and technological roles. Small angle scattering techniques, combined with complementary methods, provide an efficient approach to characterise plant cell walls, covering a broad and relevant size range while minimising experimental artefacts derived from sample treatment. Given the system complexity, approaches such as component extraction and the use of plant cell wall analogues are typically employed to enable the interpretation of experimental results. This review summarises the current research status on the characterisation of the hierarchical structure of plant cell walls using small angle scattering techniques.
Collapse
|
36
|
Creff A, Brocard L, Ingram G. A mechanically sensitive cell layer regulates the physical properties of the Arabidopsis seed coat. Nat Commun 2015; 6:6382. [DOI: 10.1038/ncomms7382] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/23/2015] [Indexed: 01/28/2023] Open
|
37
|
Thermophysical properties of lignocellulose: a cell-scale study down to 41 K. PLoS One 2014; 9:e114821. [PMID: 25532131 PMCID: PMC4273982 DOI: 10.1371/journal.pone.0114821] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 10/19/2014] [Indexed: 11/19/2022] Open
Abstract
Thermal energy transport is of great importance in lignocellulose pyrolysis for biofuels. The thermophysical properties of lignocellulose significantly affect the overall properties of bio-composites and the related thermal transport. In this work, cell-scale lignocellulose (mono-layer plant cells) is prepared to characterize their thermal properties from room temperature down to ∼40 K. The thermal conductivities of cell-scale lignocellulose along different directions show a little anisotropy due to the cell structure anisotropy. It is found that with temperature going down, the volumetric specific heat of the lignocellulose shows a slower decreasing trend against temperature than microcrystalline cellulose, and its value is always higher than that of microcrystalline cellulose. The thermal conductivity of lignocellulose decreases with temperature from 243 K to 317 K due to increasing phonon-phonon scatterings. From 41 K to 243 K, the thermal conductivity rises with temperature and its change mainly depends on the heat capacity's change.
Collapse
|
38
|
Szymanski DB. The kinematics and mechanics of leaf expansion: new pieces to the Arabidopsis puzzle. CURRENT OPINION IN PLANT BIOLOGY 2014; 22:141-148. [PMID: 25460079 DOI: 10.1016/j.pbi.2014.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 05/20/2023]
Abstract
Leaves are the primary organs for photosynthesis, and their angle, size, and timing of deployment determine the light capture efficiency of the canopy. Therefore, leaf development is an important trait in both natural and managed populations. In dicot leaves, the spatial and temporal patterns of cell division and expansion are heterogeneous, and a long-standing challenge has been to understand how subcellular and cellular growth processes can operate across broad spatial scales to influence the macroscopic growth of leaves. This review focuses on recent time-lapse analyses that help to clarify relationships between the polarized growth of individual cells, the growth behaviors of cell clusters, and leaf morphology.
Collapse
Affiliation(s)
- Daniel B Szymanski
- Purdue University, Department of Botany and Plant Pathology, United States; Purdue University, Department of Biological Sciences, United States.
| |
Collapse
|
39
|
Guzmán P, Fernández V, Graça J, Cabral V, Kayali N, Khayet M, Gil L. Chemical and structural analysis of Eucalyptus globulus and E. camaldulensis leaf cuticles: a lipidized cell wall region. FRONTIERS IN PLANT SCIENCE 2014; 5:481. [PMID: 25278953 PMCID: PMC4165216 DOI: 10.3389/fpls.2014.00481] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/30/2014] [Indexed: 05/04/2023]
Abstract
The plant cuticle has traditionally been conceived as an independent hydrophobic layer that covers the external epidermal cell wall. Due to its complexity, the existing relationship between cuticle chemical composition and ultra-structure remains unclear to date. This study aimed to examine the link between chemical composition and structure of isolated, adaxial leaf cuticles of Eucalyptus camaldulensis and E. globulus by the gradual extraction and identification of lipid constituents (cutin and soluble lipids), coupled to spectroscopic and microscopic analyses. The soluble compounds and cutin monomers identified could not be assigned to a concrete internal cuticle ultra-structure. After cutin depolymerization, a cellulose network resembling the cell wall was observed, with different structural patterns in the regions ascribed to the cuticle proper and cuticular layer, respectively. Our results suggest that the current cuticle model should be revised, stressing the presence and major role of cell wall polysaccharides. It is concluded that the cuticle may be interpreted as a modified cell wall region which contains additional lipids. The major heterogeneity of the plant cuticle makes it difficult to establish a direct link between cuticle chemistry and structure with the existing methodologies.
Collapse
Affiliation(s)
- Paula Guzmán
- Forest Genetics and Ecophysiology Research Group, School of Forest Engineering, Technical University of MadridMadrid, Spain
| | - Victoria Fernández
- Forest Genetics and Ecophysiology Research Group, School of Forest Engineering, Technical University of MadridMadrid, Spain
| | - José Graça
- Instituto Superior de Agronomia, Centro de Estudos Florestais, Universidade de LisboaLisboa, Portugal
| | - Vanessa Cabral
- Instituto Superior de Agronomia, Centro de Estudos Florestais, Universidade de LisboaLisboa, Portugal
| | - Nour Kayali
- Mass Spectrometry Unit, Faculty of Chemistry, University Complutense of MadridMadrid, Spain
| | - Mohamed Khayet
- Department of Applied Physics I, Faculty of Physics, University Complutense of MadridMadrid, Spain
| | - Luis Gil
- Forest Genetics and Ecophysiology Research Group, School of Forest Engineering, Technical University of MadridMadrid, Spain
| |
Collapse
|
40
|
Sebaa HS, Harche MK. Anatomical structure and ultrastructure of the endocarp cell walls of Argania spinosa (L.) Skeels (Sapotaceae). Micron 2014; 67:100-106. [PMID: 25125280 DOI: 10.1016/j.micron.2014.07.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 07/02/2014] [Accepted: 07/08/2014] [Indexed: 11/17/2022]
Abstract
The anatomical and histochemical study of young and adult endocarps of Argania spinosa (sampled from Tindouf; Algeria) shows a general structure that is similar to that of majority of stone fruits. These samples consist of tissues that contain lignified and cellulosic cell walls. The majority of the tissues are composed of sclerenchyma cells; with very thick lignified cell walls and conducting tissues. Coniferyl lignins are abundant in the majority of the lignified tissues. However, the coniferyl lignins appear at the primary xylem during lignification. Syringyl lignins are present in small quantities. The electron microscopy observation of the sclerenchyma cell walls of the young endocarp shows polylamellate strates and, cellular microfibrils in arced patterns. This architecture is observed in the cell walls of the adult endocarp only after the incubation of the tissue in methylamine. These configurations (arcs) are the result of a regular and complete rotation with a 180° variation in the microfibril angle; the complete and symmetrical arcs show a helicoidal mode of construction. The observation of the sclerenchyma cells revealed the capacity of helicoidal morphogenesis to adjust itself under the influence of topological constraints, such as the presence of a large number of pit canals, which maintain symplastic transport.
Collapse
Affiliation(s)
- H S Sebaa
- Laboratoire des Productions, Valorisations Végétales et Microbiennes, Département deBiotechnologie, Université des sciences et de la technologie d'Oran Mohamed Boudiaf (USTO-MB), BP 1505, El M'naouer, Oran, Algérie.
| | - M Kaid Harche
- Laboratoire des Productions, Valorisations Végétales et Microbiennes, Département deBiotechnologie, Université des sciences et de la technologie d'Oran Mohamed Boudiaf (USTO-MB), BP 1505, El M'naouer, Oran, Algérie.
| |
Collapse
|
41
|
Komis G, Mistrik M, Šamajová O, Doskočilová A, Ovečka M, Illés P, Bartek J, Šamaj J. Dynamics and organization of cortical microtubules as revealed by superresolution structured illumination microscopy. PLANT PHYSIOLOGY 2014; 165:129-48. [PMID: 24686112 PMCID: PMC4012574 DOI: 10.1104/pp.114.238477] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 03/28/2014] [Indexed: 05/07/2023]
Abstract
Plants employ acentrosomal mechanisms to organize cortical microtubule arrays essential for cell growth and differentiation. Using structured illumination microscopy (SIM) adopted for the optimal documentation of Arabidopsis (Arabidopsis thaliana) hypocotyl epidermal cells, dynamic cortical microtubules labeled with green fluorescent protein fused to the microtubule-binding domain of the mammalian microtubule-associated protein MAP4 and with green fluorescent protein-fused to the alpha tubulin6 were comparatively recorded in wild-type Arabidopsis plants and in the mitogen-activated protein kinase mutant mpk4 possessing the former microtubule marker. The mpk4 mutant exhibits extensive microtubule bundling, due to increased abundance and reduced phosphorylation of the microtubule-associated protein MAP65-1, thus providing a very useful genetic tool to record intrabundle microtubule dynamics at the subdiffraction level. SIM imaging revealed nano-sized defects in microtubule bundling, spatially resolved microtubule branching and release, and finally allowed the quantification of individual microtubules within cortical bundles. Time-lapse SIM imaging allowed the visualization of subdiffraction, short-lived excursions of the microtubule plus end, and dynamic instability behavior of both ends during free, intrabundle, or microtubule-templated microtubule growth and shrinkage. Finally, short, rigid, and nondynamic microtubule bundles in the mpk4 mutant were observed to glide along the parent microtubule in a tip-wise manner. In conclusion, this study demonstrates the potential of SIM for superresolution time-lapse imaging of plant cells, showing unprecedented details accompanying microtubule dynamic organization.
Collapse
Affiliation(s)
- George Komis
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Martin Mistrik
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Olga Šamajová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Anna Doskočilová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Miroslav Ovečka
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Peter Illés
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Jiri Bartek
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | | |
Collapse
|
42
|
Wilts BD, Whitney HM, Glover BJ, Steiner U, Vignolini S. Natural Helicoidal Structures: Morphology, Self-assembly and Optical Properties. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.matpr.2014.09.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
43
|
Jacques E, Verbelen JP, Vissenberg K. Review on shape formation in epidermal pavement cells of the Arabidopsis leaf. FUNCTIONAL PLANT BIOLOGY 2014; 41:914-921. [PMID: 0 DOI: 10.1071/fp13338] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 04/22/2014] [Indexed: 05/19/2023]
Abstract
Epidermal pavement cells appear with a fascinating irregular wavy shape in the Arabidopsis thaliana leaf. This review addresses the questions of why this particular shape is produced during leaf development and how this is accomplished. To answer the first question most probably waviness offers some biomechanical benefits over other organisations. Different positions of lobe-formation are therefore explored and discussed. At the moment, however, no hard evidence that favours any one morphology is available. The latter question comprises the biomechanical accomplishment of shape and refers to the cell wall and cytoskeletal involvement herein. A current model for pavement cell development is discussed but remaining questions and pitfalls are put forward. Moreover, an overview of the genetic and biochemical regulatory pathways that are described up to date in the literature is presented.
Collapse
|
44
|
Ivakov A, Persson S. Plant cell shape: modulators and measurements. FRONTIERS IN PLANT SCIENCE 2013; 4:439. [PMID: 24312104 PMCID: PMC3832843 DOI: 10.3389/fpls.2013.00439] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/14/2013] [Indexed: 05/19/2023]
Abstract
Plant cell shape, seen as an integrative output, is of considerable interest in various fields, such as cell wall research, cytoskeleton dynamics and biomechanics. In this review we summarize the current state of knowledge on cell shape formation in plants focusing on shape of simple cylindrical cells, as well as in complex multipolar cells such as leaf pavement cells and trichomes. We summarize established concepts as well as recent additions to the understanding of how cells construct cell walls of a given shape and the underlying processes. These processes include cell wall synthesis, activity of the actin and microtubule cytoskeletons, in particular their regulation by microtubule associated proteins, actin-related proteins, GTP'ases and their effectors, as well as the recently-elucidated roles of plant hormone signaling and vesicular membrane trafficking. We discuss some of the challenges in cell shape research with a particular emphasis on quantitative imaging and statistical analysis of shape in 2D and 3D, as well as novel developments in this area. Finally, we review recent examples of the use of novel imaging techniques and how they have contributed to our understanding of cell shape formation.
Collapse
Affiliation(s)
- Alexander Ivakov
- *Correspondence: Alexander Ivakov and Staffan Persson, Max-Planck-Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany e-mail: ;
| | - Staffan Persson
- *Correspondence: Alexander Ivakov and Staffan Persson, Max-Planck-Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany e-mail: ;
| |
Collapse
|
45
|
Characterization of crystalline cellulose in biomass: Basic principles, applications, and limitations of XRD, NMR, IR, Raman, and SFG. KOREAN J CHEM ENG 2013. [DOI: 10.1007/s11814-013-0162-0] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
46
|
Jacques E, Verbelen JP, Vissenberg K. Mechanical stress in Arabidopsis leaves orients microtubules in a 'continuous' supracellular pattern. BMC PLANT BIOLOGY 2013; 13:163. [PMID: 24138025 PMCID: PMC3853881 DOI: 10.1186/1471-2229-13-163] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 10/09/2013] [Indexed: 05/02/2023]
Abstract
BACKGROUND Cortical microtubules form a dynamic network and continuously undergo shrinking (catastrophe), pausing and rebuilding (rescue). The advantage of such a dynamic system is that it may mediate appropriate responses in a short time span. Microtubules are known to play a pivotal role in determining the orientation of the cellulose microfibril deposition in the plant cell wall. The latter is a solid exoskeleton surrounding the protoplast. It forms the physical framework that interconnects most cells and has to bear the tensile stresses within the tissue. Here we describe the effect of externally applied pressure on microtubule organization in growing Arabidopsis leaves. RESULTS Confocal microscopy examination of transgenic plants bearing GFP-tagged TUA6 proteins led to the observation that application of an additional mechanical pressure on growing Arabidopsis leaves triggers an excessive bundling of microtubules within the individual cell. Besides, the microtubules seem to align in neighboring cells, creating a 'continuous' supracellular pattern. This effect occurs within 3 hours after applied external force and is age-dependent, whereby only cells of leaves up to 19 days after sowing (DAS) are susceptible to the applied pressure. CONCLUSIONS Upon externally applied pressure on developing Arabidopsis leaves, microtubules bundle and rearrange to form seemingly continuous supracellular patterns. As microtubules guide the cellulose synthase complexes, this observed reorganisation pattern probably affects the cellulose deposition, contributing to the reinforcement of the cell wall in a particular position to cope with the extra-applied pressure. The age-effect is reasonable, since younger cells, which are actively shaping their cell walls, are more vulnerable to altered mechanical stresses while in leaves older than 19 DAS, the walls are more robust and therefore can sustain the applied forces.
Collapse
Affiliation(s)
- Eveline Jacques
- Department Biology, Plant Growth and Development, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Jean-Pierre Verbelen
- Department Biology, Plant Growth and Development, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Kris Vissenberg
- Department Biology, Plant Growth and Development, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| |
Collapse
|
47
|
Strout G, Russell SD, Pulsifer DP, Erten S, Lakhtakia A, Lee DW. Silica nanoparticles aid in structural leaf coloration in the Malaysian tropical rainforest understorey herb Mapania caudata. ANNALS OF BOTANY 2013; 112:1141-8. [PMID: 23960046 PMCID: PMC3783236 DOI: 10.1093/aob/mct172] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 06/11/2013] [Indexed: 05/22/2023]
Abstract
BACKGROUND AND AIMS Blue-green iridescence in the tropical rainforest understorey sedge Mapania caudata creates structural coloration in its leaves through a novel photonic mechanism. Known structures in plants producing iridescent blues consist of altered cellulose layering within cell walls and in special bodies, and thylakoid membranes in specialized plastids. This study was undertaken in order to determine the origin of leaf iridescence in this plant with particular attention to nano-scale components contributing to this coloration. METHODS Adaxial walls of leaf epidermal cells were characterized using high-pressure-frozen freeze-substituted specimens, which retain their native dimensions during observations using transmission and scanning microscopy, accompanied by energy-dispersive X-ray spectroscopy to identify the role of biogenic silica in wall-based iridescence. Biogenic silica was experimentally removed using aqueous Na2CO3 and optical properties were compared using spectral reflectance. KEY RESULTS AND CONCLUSIONS Blue iridescence is produced in the adaxial epidermal cell wall, which contains helicoid lamellae. The blue iridescence from cell surfaces is left-circularly polarized. The position of the silica granules is entrained by the helicoid microfibrillar layers, and granules accumulate at a uniform position within the helicoids, contributing to the structure that produces the blue iridescence, as part of the unit cell responsible for 2 ° Bragg scatter. Removal of silica from the walls eliminated the blue colour. Addition of silica nanoparticles on existing cellulosic lamellae is a novel mechanism for adding structural colour in organisms.
Collapse
Affiliation(s)
- Greg Strout
- Samuel Roberts Noble Electron Microscopy Laboratory, University of Oklahoma, Norman, OK 73019, USA
| | - Scott D. Russell
- Samuel Roberts Noble Electron Microscopy Laboratory, University of Oklahoma, Norman, OK 73019, USA
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Drew P. Pulsifer
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, USA
| | - Sema Erten
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, USA
| | - Akhlesh Lakhtakia
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, USA
| | - David W. Lee
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| |
Collapse
|
48
|
Nick P. Microtubules, signalling and abiotic stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:309-23. [PMID: 23311499 DOI: 10.1111/tpj.12102] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 12/06/2012] [Accepted: 12/17/2012] [Indexed: 05/18/2023]
Abstract
Plant microtubules, in addition to their role in cell division and axial cell expansion, convey a sensory function that is relevant for the perception of mechanical membrane stress and its derivatives, such as osmotic or cold stress. During development, sensory microtubules participate in the mechanical integration of plant architecture, including the patterning of incipient organogenesis and the alignment with gravity-dependent load. The sensory function of microtubules depends on dynamic instability, and often involves a transient elimination of cortical microtubules followed by adaptive events accompanied by subsequent formation of stable microtubule bundles. It is proposed that microtubules, because of their relative rigidity in combination with their innate nonlinear dynamics, are pre-adapted for a function as mechanosensors and, in concert with the flexible actin filaments and the anisotropic cell wall, comprise a tensegral system that allows plant cells to sense geometry and to respond to fields of mechanical strains such that the load is minimized. Microtubules are proposed as elements of a sensory hub that decodes stress-related signal signatures, with phospholipase D as an important player.
Collapse
Affiliation(s)
- Peter Nick
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76128 Karlsruhe, Germany.
| |
Collapse
|
49
|
|
50
|
Kutschera U, Niklas KJ. Cell division and turgor-driven stem elongation in juvenile plants: a synthesis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 207:45-56. [PMID: 23602098 DOI: 10.1016/j.plantsci.2013.02.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 01/16/2013] [Accepted: 02/08/2013] [Indexed: 05/23/2023]
Abstract
The growth of hypocotyls and epicotyls has been attributed to the turgor-driven enlargement of cells, a process that is under the control of phytohormones such as auxin. However, the experiments presented here and elsewhere using developing sunflower (Helianthus annuus L.) seedlings raised either in darkness (skotomorphogenesis) or in white light (WL) (photomorphogenesis) indicate that auxin-mediated segment elongation ceases after 1 day, whereas hypocotyl growth continues in the intact system. Based on these results and data from the literature, we propose that hypocotyl growth consists of three inter-related processes: (1) cell division in the apical meristematic regions; (2) turgor-driven cell elongation along the stem; and (3) cell maturation in the basal region of the organ. We document that the closed apical hook (or the corresponding region after opening in WL) is the location where cell division occurs, and suggest that the epidermis and the outer cortex plays an important role in a "pacemaker system" for cell division. Results from the literature support the hypothesis that pectin metabolism in the expansion-limiting epidermal cell wall(s) is involved in wall-loosening and -stiffening. During hypocotyl growth in darkness and WL, turgor pressure is largely maintained, i.e., in H. annuus no hydrostatic pressure-regulated growth occurs. These data do not support the "loss of stability theory" of cell expansion. Finally, we document that turgor maintenance during organ elongation is caused by sucrose catabolism via vacuolar acid invertases, resulting in the generation of hexoses (osmoregulation). Based on these data, we present an integrative model of axial elongation in developing seedlings of dicotyledonous plants and discuss open questions.
Collapse
Affiliation(s)
- Ulrich Kutschera
- Institute of Biology, University of Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany.
| | | |
Collapse
|