1
|
Boscq S, Billoud B, Theodorou I, Joemmanbaks T, Dufourt T, Charrier B. MUM, a maternal unknown message, inhibits early establishment of the medio-lateral axis in the embryo of the kelp Saccharina latissima. Development 2024; 151:dev202732. [PMID: 39190296 PMCID: PMC11423915 DOI: 10.1242/dev.202732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 07/30/2024] [Indexed: 08/28/2024]
Abstract
Brown algae are multicellular photosynthetic organisms that have evolved independently of plants and other algae. Here, we have studied the determinism of body axis formation in the kelp Saccharina latissima. After microdissection of the embryo, we show that the stalk, an empty cell that retains the embryo on the maternal tissue, represses longitudinal cell divisions in the early embryo, thereby reinforcing the establishment of the initial apico-basal axis. In addition, it promotes cell growth and controls cell shape and arrangement in the flat oblong embryo composed of cells aligned in rows and columns. Although the stalk persists for several weeks until the embryo reaches at least 500 cells, proper embryogenesis requires connection to maternal tissue only during the first 4 days after fertilisation, i.e. before the embryo reaches the 8-cell stage. Transplantation experiments indicate that the maternal signal is not diffused in seawater, but requires contact between the embryo and the maternal tissue. This first global quantitative study of brown algal embryogenesis highlights the role of MUM, an unknown maternal message, in the control of growth axes and tissue patterning in kelp embryos.
Collapse
Affiliation(s)
- Samuel Boscq
- Morphogenesis of Macro Algae, UMR8227, CNRS - Sorbonne University, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France
| | - Bernard Billoud
- Morphogenesis of Macro Algae, UMR8227, CNRS - Sorbonne University, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France
| | - Ioannis Theodorou
- Morphogenesis of Macro Algae, UMR8227, CNRS - Sorbonne University, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France
| | - Tanweer Joemmanbaks
- Morphogenesis of Macro Algae, UMR8227, CNRS - Sorbonne University, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France
| | - Tanguy Dufourt
- Institut de Génomique Fonctionnelle de Lyon (IGFL), UMR5242, ENS-Lyon, CNRS, INRAE, UCBL, 32-34 Avenue Tony Garnier, 69007 Lyon, France
| | - Bénédicte Charrier
- Morphogenesis of Macro Algae, UMR8227, CNRS - Sorbonne University, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France
| |
Collapse
|
2
|
Batista RA, Wang L, Bogaert KA, Coelho SM. Insights into the molecular bases of multicellular development from brown algae. Development 2024; 151:dev203004. [PMID: 39302848 DOI: 10.1242/dev.203004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2024]
Abstract
The transition from simple to complex multicellularity represents a major evolutionary step that occurred in only a few eukaryotic lineages. Comparative analyses of these lineages provide insights into the molecular and cellular mechanisms driving this transition, but limited understanding of the biology of some complex multicellular lineages, such as brown algae, has hampered progress. This Review explores how recent advances in genetic and genomic technologies now allow detailed investigations into the molecular bases of brown algae development. We highlight how forward genetic techniques have identified mutants that enhance our understanding of pattern formation and sexual differentiation in these organisms. Additionally, the existence and nature of morphogens in brown algae and the potential influence of the microbiome in key developmental processes are examined. Outstanding questions, such as the identity of master regulators, the definition and characterization of cell types, and the molecular bases of developmental plasticity are discussed, with insights into how recent technical advances could provide answers. Overall, this Review highlights how brown algae are emerging as alternative model organisms, contributing to our understanding of the evolution of multicellular life and the diversity of body plans.
Collapse
Affiliation(s)
- Rita A Batista
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Liping Wang
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Kenny A Bogaert
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Susana M Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| |
Collapse
|
3
|
Pedrosa LDF, Fabi JP. Dietary fiber as a wide pillar of colorectal cancer prevention and adjuvant therapy. Crit Rev Food Sci Nutr 2024; 64:6177-6197. [PMID: 36606552 DOI: 10.1080/10408398.2022.2164245] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Colorectal cancer is the third most incident and second most lethal type of cancer worldwide. Lifestyle and dietary patterns are the key factors for higher disease development risk. The dietary fiber intake from fruits and vegetables, mainly formed by food hydrocolloids, can help to lower the incidence of this type of neoplasia. Different food polysaccharides have applications in anti-tumoral therapy, such as coadjuvant to mainstream drugs, carriage-like properties, or direct influence on tumoral cells. Some classes include inulin, β-glucans, pectins, fucoidans, alginates, mucilages, and gums. Therefore, it is fundamental to discuss colorectal cancer mechanisms and the roles played by different polysaccharides in intestinal health. Genetic, environmental, and immunological modulation of mutated pathways regarding colorectal cancer has been explored before. Microbial diversity, byproduct formation (primarily short-chain fatty acids), inflammatory profile control, and tumoral mutated pathways regulation are thoroughly explored mechanisms by which dietary fiber sources influence a healthy gut ambiance.
Collapse
Affiliation(s)
- Lucas de Freitas Pedrosa
- Department of Food Science and Experimental Nutrition, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - João Paulo Fabi
- Food and Nutrition Research Center (NAPAN), University of São Paulo, São Paulo, SP, Brazil
- Food Research Center (FoRC), CEPID-FAPESP (Research, Innovation and Dissemination Centers, São Paulo Research Foundation), São Paulo, SP, Brazil
| |
Collapse
|
4
|
Awanthi MGG, Umosa M, Yuguchi Y, Oku H, Kitahara K, Ito M, Tanaka A, Konishi T. Fractionation and characterization of cell wall polysaccharides from the brown alga Cladosiphon okamuranus. Carbohydr Res 2023; 523:108722. [PMID: 36459703 DOI: 10.1016/j.carres.2022.108722] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/01/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022]
Abstract
Brown algae contain a polysaccharide-rich cell wall, mainly composed of alginate and fucoidan which have been extensively studied for their individual structure and bioactivities. Particularly, the cell wall of Cladosiphon okamuranus is rich in fucoidan rather than alginate. However, little is known about its arrangement or interlinking with other polysaccharides such as cellulose in the cell wall. To determine its structure in detail, the cell wall was sequentially fractionated into five fractions: hot water (HW), ammonium oxalate, hemicellulose-I (HC-I), HC-II, and cellulose. Almost 80% of the total cell wall recovered from alcohol insoluble residue in C. okamuranus consisted of HW and HC-I, which mainly contained fucoidan composed of fucose, glucuronic acid, and sulfate in molar ratios of 1.0:0.3:0.9 and 1.0:0.2:0.3, respectively. Methylation analysis revealed that fucoidan in HW and HC-I structurally differed in terms of content of sulfate, and sugar residue which was 1,4-linked xylose and 1,4-linked fucose. Small angle X-ray scattering measurements also showed distinct conformational differences between HW and HC-I. These structural heterogeneities of fucoidan may be related to their localization, and fucoidan in HC-I may be involved in reinforcing cell wall structure by cross-linking to cellulose.
Collapse
Affiliation(s)
- Mahanama Geegana Gamage Awanthi
- United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima-shi, Kagoshima, 890-0065, Japan
| | - Manatsu Umosa
- Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa, 903-0213, Japan
| | - Yoshiaki Yuguchi
- Faculty of Engineering, Osaka Electro-Communication University, 18-8 Hatsucho, Neyagawa-shi, Osaka, 572-8530, Japan
| | - Hirosuke Oku
- United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima-shi, Kagoshima, 890-0065, Japan; Center of Molecular Biosciences, Tropical Biosphere Research Center, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa, 903-0213, Japan
| | - Kanefumi Kitahara
- United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima-shi, Kagoshima, 890-0065, Japan; Department of Food Science and Biotechnology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima-shi, Kagoshima, 890-0065, Japan
| | - Michihiro Ito
- Center of Molecular Biosciences, Tropical Biosphere Research Center, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa, 903-0213, Japan
| | - Atsuko Tanaka
- Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa, 903-0213, Japan
| | - Teruko Konishi
- United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima-shi, Kagoshima, 890-0065, Japan; Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa, 903-0213, Japan.
| |
Collapse
|
5
|
Clerc T, Boscq S, Attia R, Kaminski Schierle GS, Charrier B, Läubli NF. Cultivation and Imaging of S. latissima Embryo Monolayered Cell Sheets Inside Microfluidic Devices. Bioengineering (Basel) 2022; 9:bioengineering9110718. [PMID: 36421119 PMCID: PMC9687954 DOI: 10.3390/bioengineering9110718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/08/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
The culturing and investigation of individual marine specimens in lab environments is crucial to further our understanding of this highly complex ecosystem. However, the obtained results and their relevance are often limited by a lack of suitable experimental setups enabling controlled specimen growth in a natural environment while allowing for precise monitoring and in-depth observations. In this work, we explore the viability of a microfluidic device for the investigation of the growth of the alga Saccharina latissima to enable high-resolution imaging by confining the samples, which usually grow in 3D, to a single 2D plane. We evaluate the specimen’s health based on various factors such as its growth rate, cell shape, and major developmental steps with regard to the device’s operating parameters and flow conditions before demonstrating its compatibility with state-of-the-art microscopy imaging technologies such as the skeletonisation of the specimen through calcofluor white-based vital staining of its cell contours as well as the immunolocalisation of the specimen’s cell wall. Furthermore, by making use of the on-chip characterisation capabilities, we investigate the influence of altered environmental illuminations on the embryonic development using blue and red light. Finally, live tracking of fluorescent microspheres deposited on the surface of the embryo permits the quantitative characterisation of growth at various locations of the organism.
Collapse
Affiliation(s)
- Thomas Clerc
- Morphogenesis of Macroalgae, Laboratory of Integrative Biology of Marine Models, Station Biologique de Roscoff, CNRS, Sorbonne University, 29680 Roscoff, France
| | - Samuel Boscq
- Morphogenesis of Macroalgae, Laboratory of Integrative Biology of Marine Models, Station Biologique de Roscoff, CNRS, Sorbonne University, 29680 Roscoff, France
| | - Rafaele Attia
- Ecology of Marine Plankton, Laboratory of Adaptation and Diversity in the Marine Environment, Station Biologique de Roscoff, CNRS, Sorbonne University, 29680 Roscoff, France
| | - Gabriele S. Kaminski Schierle
- Molecular Neuroscience Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, UK
| | - Bénédicte Charrier
- Morphogenesis of Macroalgae, Laboratory of Integrative Biology of Marine Models, Station Biologique de Roscoff, CNRS, Sorbonne University, 29680 Roscoff, France
- Correspondence: (B.C.); (N.F.L.)
| | - Nino F. Läubli
- Molecular Neuroscience Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, UK
- Correspondence: (B.C.); (N.F.L.)
| |
Collapse
|
6
|
Graf L, Shin Y, Yang JH, Hwang IK, Yoon HS. Transcriptome analysis reveals the spatial and temporal differentiation of gene expression in the sporophyte of Undaria pinnatifida. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
7
|
Wu Q, Li Y, Lyu M, Luo Y, Shi H, Zhong S. Touch-induced seedling morphological changes are determined by ethylene-regulated pectin degradation. SCIENCE ADVANCES 2020; 6:6/48/eabc9294. [PMID: 33246960 PMCID: PMC7695475 DOI: 10.1126/sciadv.abc9294] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 10/15/2020] [Indexed: 05/08/2023]
Abstract
How mechanical forces regulate plant growth is a fascinating and long-standing question. After germination underground, buried seedlings have to dynamically adjust their growth to respond to mechanical stimulation from soil barriers. Here, we designed a lid touch assay and used atomic force microscopy to investigate the mechanical responses of seedlings during soil emergence. Touching seedlings induced increases in cell wall stiffness and decreases in cell elongation, which were correlated with pectin degradation. We revealed that PGX3, which encodes a polygalacturonase, mediates touch-imposed alterations in the pectin matrix and the mechanics of morphogenesis. Furthermore, we found that ethylene signaling is activated by touch, and the transcription factor EIN3 directly associates with PGX3 promoter and is required for touch-repressed PGX3 expression. By uncovering the link between mechanical forces and cell wall remodeling established via the EIN3-PGX3 module, this work represents a key step in understanding the molecular framework of touch-induced morphological changes.
Collapse
Affiliation(s)
- Qingqing Wu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yue Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Mohan Lyu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yiwen Luo
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Hui Shi
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Shangwei Zhong
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.
| |
Collapse
|
8
|
Sheng H, Chen S. Plant silicon-cell wall complexes: Identification, model of covalent bond formation and biofunction. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 155:13-19. [PMID: 32736240 DOI: 10.1016/j.plaphy.2020.07.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/12/2020] [Accepted: 07/13/2020] [Indexed: 05/10/2023]
Abstract
Silicon (Si) is the second most abundant element on earth crust, consisting primarily of silicate minerals. Si is found in the tissues of almost all terrestrial plants and is mostly deposited in specialized cells or cell walls as amorphous silica. Numerous discoveries have shown that in addition to non-covalent interactions through amorphous silica, Si can form covalent bonds with plant cell wall components such as hemicelluloses, pectin and lignin. The covalent bonds may be formed via Si-O-C linkages between monosilicic acid (H4SiO4) and cis-diols of cell wall polysaccharides or lignin. The covalently bound organosilicon, independent of amorphous inorganic silica, may play a crucial role in plant cell wall structure and remodeling and thus plant growth and its resistance against biotic and abiotic stresses. This review discusses the existing research on the discovery of plant silicon-cell wall complexes and proposes a model of their covalent bond formation and biofunction.
Collapse
Affiliation(s)
- Huachun Sheng
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, Shaanxi, 712100, PR China; College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, PR China.
| | - Shaolin Chen
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, Shaanxi, 712100, PR China; College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, PR China; Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, Northwest A&F University, Yangling, Shaanxi, 712100, PR China.
| |
Collapse
|
9
|
Halat L, Galway ME, Garbary DJ. Cell wall structural changes lead to separation and shedding of biofouled epidermal cell wall layers by the brown alga Ascophyllum nodosum. PROTOPLASMA 2020; 257:1319-1331. [PMID: 32507923 DOI: 10.1007/s00709-020-01502-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 03/18/2020] [Indexed: 06/11/2023]
Abstract
Marine plants control the accumulation of biofouling organisms (epibionts) on their surfaces by various chemical and physical means. Ascophyllum nodosum is a perennial multicellular brown alga known to shed patches of epidermal material, thus removing epibionts and exposing unfouled surfaces to another cycle of colonization. While surface shedding is documented in multiple marine macroalgae, the cell and developmental biology of the phenomenon is almost unexplored. A previous investigation of Ascophyllum not only revealed regular cycles of epibiont accumulation and epidermal shedding but also stimulated the development of methods to detect the corresponding changes in epidermal (meristoderm) cells that are reported here. Confocal laser scanning microscopy of cell walls and cytoplasm fluorescently stained with Solophenyl Flavine 7GFE (Direct Yellow 96) and the lipophilic dye Rhodamine B (respectively) was combined with light and electron microscopy of chemically fixed or freeze-substituted tissues. As epibionts accumulated, epidermal cells generated thick, apical cell walls in which differentially stained central layers subsequently developed, marking the site of future cell wall separation. During cell wall separation, the outermost part of the cell wall and its epibionts plus the upper parts of the anticlinal walls between neighboring cells detached in a layer from multiple epidermal cells, exposing the remaining inner part of the cell wall to new colonizing organisms. These findings highlight the dynamic nature of apical cell wall structure and composition in response to colonizing organisms and lay a foundation for further investigations on the periodic removal of biofouling epibionts from the surface of Ascophyllum fronds.
Collapse
Affiliation(s)
- Laryssa Halat
- Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 2W5, Canada
- Department of Botany, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Moira E Galway
- Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 2W5, Canada.
| | - David J Garbary
- Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 2W5, Canada
- Jack McLachlan Laboratory of Aquatic Plant Resources, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 2W5, Canada
| |
Collapse
|
10
|
Rabillé H, Torode TA, Tesson B, Le Bail A, Billoud B, Rolland E, Le Panse S, Jam M, Charrier B. Alginates along the filament of the brown alga Ectocarpus help cells cope with stress. Sci Rep 2019; 9:12956. [PMID: 31506545 PMCID: PMC6736953 DOI: 10.1038/s41598-019-49427-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/23/2019] [Indexed: 11/29/2022] Open
Abstract
Ectocarpus is a filamentous brown alga, which cell wall is composed mainly of alginates and fucans (80%), two non-crystalline polysaccharide classes. Alginates are linear chains of epimers of 1,4-linked uronic acids, β-D-mannuronic acid (M) and α-L-guluronic acid (G). Previous physico-chemical studies showed that G-rich alginate gels are stiffer than M-rich alginate gels when prepared in vitro with calcium. In order to assess the possible role of alginates in Ectocarpus, we first immunolocalised M-rich or G-rich alginates using specific monoclonal antibodies along the filament. As a second step, we calculated the tensile stress experienced by the cell wall along the filament, and varied it with hypertonic or hypotonic solutions. As a third step, we measured the stiffness of the cell along the filament, using cell deformation measurements and atomic force microscopy. Overlapping of the three sets of data allowed to show that alginates co-localise with the stiffest and most stressed areas of the filament, namely the dome of the apical cell and the shanks of the central round cells. In addition, no major distinction between M-rich and G-rich alginate spatial patterns could be observed. Altogether, these results support that both M-rich and G-rich alginates play similar roles in stiffening the cell wall where the tensile stress is high and exposes cells to bursting, and that these roles are independent from cell growth and differentiation.
Collapse
Affiliation(s)
- Hervé Rabillé
- CNRS, Sorbonne Université, Laboratoire de Biologie Intégrative des Modèles Marins LBI2M, Station Biologique, Roscoff, France
| | - Thomas A Torode
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, United Kingdom
| | - Benoit Tesson
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Aude Le Bail
- CNRS, Sorbonne Université, Laboratoire de Biologie Intégrative des Modèles Marins LBI2M, Station Biologique, Roscoff, France
- Department of Cell Biology, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
| | - Bernard Billoud
- CNRS, Sorbonne Université, Laboratoire de Biologie Intégrative des Modèles Marins LBI2M, Station Biologique, Roscoff, France
| | - Elodie Rolland
- CNRS, Sorbonne Université, Laboratoire de Biologie Intégrative des Modèles Marins LBI2M, Station Biologique, Roscoff, France
| | - Sophie Le Panse
- Platform Merimage, FR 2424, CNRS, Station Biologique, Roscoff, France
| | - Murielle Jam
- Marine Glycobiology team, UMR8227, CNRS-UPMC, Station Biologique, Roscoff, France
| | - Bénédicte Charrier
- CNRS, Sorbonne Université, Laboratoire de Biologie Intégrative des Modèles Marins LBI2M, Station Biologique, Roscoff, France.
| |
Collapse
|
11
|
Rabillé H, Billoud B, Tesson B, Le Panse S, Rolland É, Charrier B. The brown algal mode of tip growth: Keeping stress under control. PLoS Biol 2019; 17:e2005258. [PMID: 30640903 PMCID: PMC6347293 DOI: 10.1371/journal.pbio.2005258] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 01/25/2019] [Accepted: 12/20/2018] [Indexed: 01/09/2023] Open
Abstract
Tip growth has been studied in pollen tubes, root hairs, and fungal and oomycete hyphae and is the most widely distributed unidirectional growth process on the planet. It ensures spatial colonization, nutrient predation, fertilization, and symbiosis with growth speeds of up to 800 μm h-1. Although turgor-driven growth is intuitively conceivable, a closer examination of the physical processes at work in tip growth raises a paradox: growth occurs where biophysical forces are low, because of the increase in curvature in the tip. All tip-growing cells studied so far rely on the modulation of cell wall extensibility via the polarized excretion of cell wall-loosening compounds at the tip. Here, we used a series of quantitative measurements at the cellular level and a biophysical simulation approach to show that the brown alga Ectocarpus has an original tip-growth mechanism. In this alga, the establishment of a steep gradient in cell wall thickness can compensate for the variation in tip curvature, thereby modulating wall stress within the tip cell. Bootstrap analyses support the robustness of the process, and experiments with fluorescence recovery after photobleaching (FRAP) confirmed the active vesicle trafficking in the shanks of the apical cell, as inferred from the model. In response to auxin, biophysical measurements change in agreement with the model. Although we cannot strictly exclude the involvement of a gradient in mechanical properties in Ectocarpus morphogenesis, the viscoplastic model of cell wall mechanics strongly suggests that brown algae have evolved an alternative strategy of tip growth. This strategy is largely based on the control of cell wall thickness rather than fluctuations in cell wall mechanical properties.
Collapse
Affiliation(s)
- Hervé Rabillé
- CNRS, Sorbonne Université, Morphogenesis of Macro Algae, UMR8227, Station Biologique, Roscoff, France
| | - Bernard Billoud
- CNRS, Sorbonne Université, Morphogenesis of Macro Algae, UMR8227, Station Biologique, Roscoff, France
| | - Benoit Tesson
- SCRIPPS Institution of Oceanography, University of California, San Diego, San Diego, California, United States of America
| | - Sophie Le Panse
- MerImage platform, FR2424, CNRS, Sorbonne Université, Station Biologique, Roscoff, France
| | - Élodie Rolland
- CNRS, Sorbonne Université, Morphogenesis of Macro Algae, UMR8227, Station Biologique, Roscoff, France
| | - Bénédicte Charrier
- CNRS, Sorbonne Université, Morphogenesis of Macro Algae, UMR8227, Station Biologique, Roscoff, France
| |
Collapse
|