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Ouonkap SVY, Palaniappan M, Pryze K, Jong E, Ali MF, Styler B, Almasaud RA, Harkey AF, Reid RW, Loraine AE, Smith SE, Muday GK, Pease JB, Palanivelu R, Johnson MA. Enhanced pollen tube performance at high temperature contributes to thermotolerant fruit production in tomato. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.01.606234. [PMID: 39149357 PMCID: PMC11326152 DOI: 10.1101/2024.08.01.606234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Rising temperature extremes during critical reproductive periods threaten the yield of major grain and fruit crops. Flowering plant reproduction depends on development of sufficient numbers of pollen grains and on their ability to generate a cellular extension, the pollen tube, which elongates through the pistil to deliver sperm cells to female gametes for double fertilization. These critical phases of the life cycle are sensitive to temperature and limit productivity under high temperature (HT). Previous studies have investigated the effects of HT on pollen development, but little is known about how HT applied during the pollen tube growth phase affects fertility. Here, we used tomato as a model fruit crop to determine how HT affects the pollen tube growth phase, taking advantage of cultivars noted for fruit production in exceptionally hot growing seasons. We found that exposure to HT solely during the pollen tube growth phase limits fruit biomass and seed set more significantly in thermosensitive cultivars than in thermotolerant cultivars. Importantly, we found that pollen tubes from the thermotolerant Tamaulipas cultivar have enhanced growth in vivo and in vitro under HT. Analysis of the pollen tube transcriptome's response to HT allowed us to develop hypotheses for the molecular basis of cellular thermotolerance in the pollen tube and we define two response modes (enhanced induction of stress responses, and higher basal levels of growth pathways repressed by heat stress) associated with reproductive thermotolerance. Importantly, we define key components of the pollen tube stress response identifying enhanced ROS homeostasis and pollen tube callose synthesis and deposition as important components of reproductive thermotolerance in Tamaulipas. Our work identifies the pollen tube growth phase as a viable target to enhance reproductive thermotolerance and delineates key pathways that are altered in crop varieties capable of fruiting under HT conditions.
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Affiliation(s)
| | | | | | - Emma Jong
- School of Plant Sciences; University of Arizona
| | | | - Benjamin Styler
- Department of Molecular Biology, Cell Biology, and Biochemistry; Brown University
| | | | | | - Robert W Reid
- Department of Bioinformatics and Genomics; UNC Charlotte
| | - Ann E Loraine
- Department of Bioinformatics and Genomics; UNC Charlotte
| | - Steven E Smith
- School of Natural Resources and the Environment; University of Arizona
| | | | - James B Pease
- Department of Evolution, Ecology and Organismal Biology; The Ohio State University
| | | | - Mark A Johnson
- Department of Molecular Biology, Cell Biology, and Biochemistry; Brown University
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2
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Kong W, Mosciatti Jofré A, Quiros M, Bogeat-Triboulot MB, Kolb E, Couturier E. Force generation by a cylindrical cell under stationary osmolyte synthesis. J R Soc Interface 2024; 21:20240204. [PMID: 39192726 DOI: 10.1098/rsif.2024.0204] [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: 03/26/2024] [Revised: 06/07/2024] [Accepted: 07/03/2024] [Indexed: 08/29/2024] Open
Abstract
Turgor is the driving force of plant growth, making it possible for roots to overcome soil resistance or for stems to counteract gravity. Maintaining a constant growth rate while avoiding cell content dilution, which would progressively stop the inward water flux, imposes the production or import of osmolytes in proportion to the increase of volume. We coin this phenomenon stationary osmoregulation. The article explores the quantitative consequences of this hypothesis on the interaction of a cylindrical cell growing axially against an obstacle. An instantaneous axial compression of a pressurized cylindrical cell generates a force and a pressure jump, which both decrease towards a lower value once water has flowed out of the cell to reach the water potential equilibrium. In the first part, the article derives analytical formulae for these forces and over-pressure both before and after relaxation. In the second part, we describe how the coupling of the Lockhart growth law with the stationary osmoregulation hypothesis predicts a transient slowdown in growth due to contact before a re-acceleration in growth. We finally compare these predictions with the output of an elastic growth model which ignores the osmotic origin of growth: models only match in the early phase of contact for a high-stiffness obstacle.
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Affiliation(s)
- Weiyuan Kong
- Laboratoire Matière et Systèmes Complexes, Université Paris Cité CNRS UMR 7057, 10 Rue Alice Domont et Léonie Ducquet , 75205 Paris, Cedex 13, France
| | - Antonio Mosciatti Jofré
- Laboratoire Matière et Systèmes Complexes, Université Paris Cité CNRS UMR 7057, 10 Rue Alice Domont et Léonie Ducquet , 75205 Paris, Cedex 13, France
| | - Manon Quiros
- PMMH, CNRS, ESPCI Paris, Université PSL, Sorbonne Université, Université de Paris , 75005 Paris, France
| | | | - Evelyne Kolb
- PMMH, CNRS, ESPCI Paris, Université PSL, Sorbonne Université, Université de Paris , 75005 Paris, France
| | - Etienne Couturier
- Laboratoire Matière et Systèmes Complexes, Université Paris Cité CNRS UMR 7057, 10 Rue Alice Domont et Léonie Ducquet , 75205 Paris, Cedex 13, France
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3
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Abstract
While the involvement of actin polymerization in cell migration is well-established, much less is known about the role of transmembrane water flow in cell motility. Here, we investigate the role of water influx in a prototypical migrating cell, the neutrophil, which undergoes rapid, directed movement to sites of injury, and infection. Chemoattractant exposure both increases cell volume and potentiates migration, but the causal link between these processes are not known. We combine single-cell volume measurements and a genome-wide CRISPR screen to identify the regulators of chemoattractant-induced neutrophil swelling, including NHE1, AE2, PI3K-gamma, and CA2. Through NHE1 inhibition in primary human neutrophils, we show that cell swelling is both necessary and sufficient for the potentiation of migration following chemoattractant stimulation. Our data demonstrate that chemoattractant-driven cell swelling complements cytoskeletal rearrangements to enhance migration speed.
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Affiliation(s)
- Tamas L Nagy
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Cardiovascular Research Institute, University of California, San FranciscoSan FranciscoUnited States
| | - Evelyn Strickland
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Cardiovascular Research Institute, University of California, San FranciscoSan FranciscoUnited States
| | - Orion D Weiner
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Cardiovascular Research Institute, University of California, San FranciscoSan FranciscoUnited States
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4
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Voothuluru P, Wu Y, Sharp RE. Not so hidden anymore: Advances and challenges in understanding root growth under water deficits. THE PLANT CELL 2024; 36:1377-1409. [PMID: 38382086 PMCID: PMC11062450 DOI: 10.1093/plcell/koae055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/09/2024] [Accepted: 02/15/2024] [Indexed: 02/23/2024]
Abstract
Limited water availability is a major environmental factor constraining plant development and crop yields. One of the prominent adaptations of plants to water deficits is the maintenance of root growth that enables sustained access to soil water. Despite early recognition of the adaptive significance of root growth maintenance under water deficits, progress in understanding has been hampered by the inherent complexity of root systems and their interactions with the soil environment. We highlight selected milestones in the understanding of root growth responses to water deficits, with emphasis on founding studies that have shaped current knowledge and set the stage for further investigation. We revisit the concept of integrated biophysical and metabolic regulation of plant growth and use this framework to review central growth-regulatory processes occurring within root growth zones under water stress at subcellular to organ scales. Key topics include the primary processes of modifications of cell wall-yielding properties and osmotic adjustment, as well as regulatory roles of abscisic acid and its interactions with other hormones. We include consideration of long-recognized responses for which detailed mechanistic understanding has been elusive until recently, for example hydrotropism, and identify gaps in knowledge, ongoing challenges, and opportunities for future research.
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Affiliation(s)
- Priya Voothuluru
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
- Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211, USA
| | - Yajun Wu
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA
| | - Robert E Sharp
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
- Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211, USA
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5
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Chocano-Coralla EJ, Vidali L. Myosin XI, a model of its conserved role in plant cell tip growth. Biochem Soc Trans 2024; 52:505-515. [PMID: 38629612 DOI: 10.1042/bst20220783] [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: 07/28/2023] [Revised: 03/21/2024] [Accepted: 03/26/2024] [Indexed: 04/25/2024]
Abstract
In eukaryotic cells, organelle and vesicle transport, positioning, and interactions play crucial roles in cytoplasmic organization and function. These processes are governed by intracellular trafficking mechanisms. At the core of that trafficking, the cytoskeleton and directional transport by motor proteins stand out as its key regulators. Plant cell tip growth is a well-studied example of cytoplasm organization by polarization. This polarization, essential for the cell's function, is driven by the cytoskeleton and its associated motors. This review will focus on myosin XI, a molecular motor critical for vesicle trafficking and polarized plant cell growth. We will center our discussion on recent data from the moss Physcomitrium patens and the liverwort Marchantia polymorpha. The biochemical properties and structure of myosin XI in various plant species are discussed, highlighting functional conservation across species. We further explore this conservation of myosin XI function in the process of vesicle transport in tip-growing cells. Existing evidence indicates that myosin XI actively organizes actin filaments in tip-growing cells by a mechanism based on vesicle clustering at their tips. A hypothetical model is presented to explain the essential function of myosin XI in polarized plant cell growth based on vesicle clustering at the tip. The review also provides insight into the in vivo localization and dynamics of myosin XI, emphasizing its role in cytosolic calcium regulation, which influences the polymerization of F-actin. Lastly, we touch upon the need for additional research to elucidate the regulation of myosin function.
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Affiliation(s)
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, U.S.A
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6
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Debora Gasperini. THE NEW PHYTOLOGIST 2024; 241:2337-2339. [PMID: 38279524 DOI: 10.1111/nph.19550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
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7
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Schoenaers S, Lee HK, Gonneau M, Faucher E, Levasseur T, Akary E, Claeijs N, Moussu S, Broyart C, Balcerowicz D, AbdElgawad H, Bassi A, Damineli DSC, Costa A, Feijó JA, Moreau C, Bonnin E, Cathala B, Santiago J, Höfte H, Vissenberg K. Rapid alkalinization factor 22 has a structural and signalling role in root hair cell wall assembly. NATURE PLANTS 2024; 10:494-511. [PMID: 38467800 DOI: 10.1038/s41477-024-01637-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/30/2024] [Indexed: 03/13/2024]
Abstract
Pressurized cells with strong walls make up the hydrostatic skeleton of plants. Assembly and expansion of such stressed walls depend on a family of secreted RAPID ALKALINIZATION FACTOR (RALF) peptides, which bind both a membrane receptor complex and wall-localized LEUCINE-RICH REPEAT EXTENSIN (LRXs) in a mutually exclusive way. Here we show that, in root hairs, the RALF22 peptide has a dual structural and signalling role in cell expansion. Together with LRX1, it directs the compaction of charged pectin polymers at the root hair tip into periodic circumferential rings. Free RALF22 induces the formation of a complex with LORELEI-LIKE-GPI-ANCHORED PROTEIN 1 and FERONIA, triggering adaptive cellular responses. These findings show how a peptide simultaneously functions as a structural component organizing cell wall architecture and as a feedback signalling molecule that regulates this process depending on its interaction partners. This mechanism may also underlie wall assembly and expansion in other plant cell types.
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Affiliation(s)
- Sébastjen Schoenaers
- Department of Biology, Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
- Institut Jean-Pierre Bourgin, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Hyun Kyung Lee
- Department of Plant Molecular Biology, The Plant Signaling Mechanisms Laboratory, University of Lausanne, Lausanne, Switzerland
| | - Martine Gonneau
- Institut Jean-Pierre Bourgin, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Elvina Faucher
- Institut Jean-Pierre Bourgin, AgroParisTech, Université Paris-Saclay, Versailles, France
| | | | - Elodie Akary
- Institut Jean-Pierre Bourgin, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Naomi Claeijs
- Department of Biology, Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
| | - Steven Moussu
- Department of Plant Molecular Biology, The Plant Signaling Mechanisms Laboratory, University of Lausanne, Lausanne, Switzerland
| | - Caroline Broyart
- Department of Plant Molecular Biology, The Plant Signaling Mechanisms Laboratory, University of Lausanne, Lausanne, Switzerland
| | - Daria Balcerowicz
- Department of Biology, Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
| | - Hamada AbdElgawad
- Department of Biology, Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
- Department of Botany and Microbiology, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - Andrea Bassi
- Department of Physics, Politecnico di Milano, Milan, Italy
| | - Daniel Santa Cruz Damineli
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- Center for Mathematics, Computing and Cognition, Federal University of ABC, Santo André, Brazil
| | - Alex Costa
- Department of Biosciences, University of Milan, Milan, Italy
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Milan, Italy
| | - José A Feijó
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | | | | | | | - Julia Santiago
- Department of Plant Molecular Biology, The Plant Signaling Mechanisms Laboratory, University of Lausanne, Lausanne, Switzerland.
| | - Herman Höfte
- Institut Jean-Pierre Bourgin, AgroParisTech, Université Paris-Saclay, Versailles, France.
| | - Kris Vissenberg
- Department of Biology, Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium.
- Department of Agriculture, Plant Biochemistry and Biotechnology Lab, Hellenic Mediterranean University, Heraklion, Greece.
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8
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Kamel H, Geitmann A. Strength in numbers: An isoform variety of homogalacturonan modifying enzymes may contribute to pollen tube fitness. PLANT PHYSIOLOGY 2023; 194:67-80. [PMID: 37819032 DOI: 10.1093/plphys/kiad544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 10/13/2023]
Abstract
Pectin is a major component of the cell wall in land plants. It plays crucial roles in cell wall assembly, cell growth, shaping, and signaling. The relative abundance of pectin in the cell wall is particularly high in rapidly growing organ regions and cell types. Homogalacturonan (HG), a polymer of 1,4-linked α-D-galacturonic acid, is a major pectin constituent in growing and dividing plant cells. In pollen tubes, an extremely rapidly growing cell type, HG is secreted at and inserted into the apical cell wall and is subject to further modification in muro by HG modifying enzymes (HGMEs). These enzymes, including pectin esterases and depolymerases, have multiple isoforms, some of which are specifically expressed in pollen. Given the importance of pectin chemistry for the fitness of pollen tubes, it is of interest to interrogate the potentially crucial roles these isoforms play in pollen germination and elongation. It is hypothesized that different HGME isoforms, through their action on apoplastic HG, may generate differential methylation and acetylation patterns endowing HG polysaccharides with specific, spatially and temporally varying properties that lead to a fine-tuned pattern of cell wall modification. In addition, these isoforms may be differentially activated and/or inhibited depending on the local conditions that may vary at subcellular resolution. In this Update we review the different HGME isoforms identified in recent years in Arabidopsis thaliana and postulate that the multiplicity of these isoforms may allow for specialized substrate recognition and conditional activation, leading to a sophisticated regulation scheme exemplified in the process that governs the dynamic properties of the cell wall in pollen tube growth.
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Affiliation(s)
- Hiba Kamel
- Department of Plant Science, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec H9X 3V9, Canada
| | - Anja Geitmann
- Department of Plant Science, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec H9X 3V9, Canada
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9
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Wang J, Shen J, Xu Y, Jiang Y, Qu X, Zhao W, Wang Y, Huang S. Differential sensitivity of ADF isovariants to a pH gradient promotes pollen tube growth. J Cell Biol 2023; 222:e202206074. [PMID: 37610419 PMCID: PMC10445753 DOI: 10.1083/jcb.202206074] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 12/20/2022] [Accepted: 08/09/2023] [Indexed: 08/24/2023] Open
Abstract
The actin cytoskeleton is one of the targets of the pH gradient in tip-growing cells, but how cytosolic pH regulates the actin cytoskeleton remains largely unknown. We here demonstrate that Arabidopsis ADF7 and ADF10 function optimally at different pH levels when disassembling actin filaments. This differential pH sensitivity allows ADF7 and ADF10 to respond to the cytosolic pH gradient to regulate actin dynamics in pollen tubes. ADF7 is an unusual actin-depolymerizing factor with a low optimum pH in in vitro actin depolymerization assays. ADF7 plays a dominant role in promoting actin turnover at the pollen tube apex. ADF10 has a typically high optimum pH in in vitro assays and plays a dominant role in regulating the turnover and organization of subapical actin filaments. Thus, functional specification and cooperation of ADF isovariants with different pH sensitivities enable the coordination of the actin cytoskeleton with the cytosolic pH gradient to support pollen tube growth.
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Affiliation(s)
- Juan Wang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jiangfeng Shen
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yanan Xu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuxiang Jiang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wanying Zhao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yingjie Wang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
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10
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Ortega JKE. Theoretical Analyses of Turgor Pressure during Stress Relaxation and Water Uptake, and after Changes in Expansive Growth Rate When Water Uptake Is Normal and Reduced. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12091891. [PMID: 37176947 PMCID: PMC10181280 DOI: 10.3390/plants12091891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/28/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023]
Abstract
Turgor pressure provides the force needed to stress and deform the cell walls of plants, algae, and fungi during expansive growth. However, turgor pressure plays another subtle but equally important role in expansive growth of walled cells: it connects the two biophysical processes of water uptake and wall deformation to ensure that the volumetric rates of water uptake and enlargement of the cell wall chamber are equal. In this study, the role of turgor pressure as a 'connector' is investigated analytically by employing validated and established biophysical equations. The objective is to determine the effect of 'wall loosening' on the magnitude of turgor pressure. It is known that an increase or decrease in turgor pressure and/or wall loosening rate increases or decreases the expansive growth rate, respectively. Interestingly, it is shown that an increase in the wall loosening rate decreases the turgor pressure slightly, thus reducing the effect of wall loosening on increasing the expansive growth rate. Other analyses reveal that reducing the rate of water uptake results in a larger decrease in turgor pressure with the same increase in wall loosening rate, which further reduces the effect of wall loosening on increasing the expansive growth rate.
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Affiliation(s)
- Joseph K E Ortega
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80217-3364, USA
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11
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Weng X, Shen Y, Jiang L, Zhao L, Wang H. Spatiotemporal organization and correlation of tip-focused exocytosis and endocytosis in regulating pollen tube tip growth. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 330:111633. [PMID: 36775070 DOI: 10.1016/j.plantsci.2023.111633] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/09/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Pollen tube polar growth is a key cellular process during plant fertilization and is regulated by tip-focused exocytosis and endocytosis. However, the spatiotemporal dynamics and localizations of apical exocytosis and endocytosis in the tip region are still a matter of debate. Here, we use a refined spinning-disk confocal microscope coupled with fluorescence recovery after photobleaching for sustained live imaging and quantitative analysis of rapid vesicular activities in growing pollen tube tips. We traced and analyzed the occurrence site of exocytic plasma membrane-targeting of Arabidopsis secretory carrier membrane protein 4 and its subsequent endocytosis in tobacco pollen tube tips. We demonstrated that the pollen tube apex is the site for both vesicle polar exocytic fusion and endocytosis to take place. In addition, we disrupted either tip-focused exocytosis or endocytosis and found that their dynamic activities are closely correlated with one another basing on the spatial organization of actin fringe. Collectively, our findings attempt to propose a new exocytosis and endocytosis-coordinated yin-yang working model underlying the apical membrane organization and dynamics during pollen tube tip growth.
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Affiliation(s)
- Xun Weng
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Yifan Shen
- Utahloy International School of Guangzhou, Guangzhou 510642, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; Institute of Plant Molecular Biology & Agricultural Biotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Lifeng Zhao
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China.
| | - Hao Wang
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China.
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12
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Ali O, Cheddadi I, Landrein B, Long Y. Revisiting the relationship between turgor pressure and plant cell growth. THE NEW PHYTOLOGIST 2023; 238:62-69. [PMID: 36527246 DOI: 10.1111/nph.18683] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
Growth is central to plant morphogenesis. Plant cells are encased in rigid cell walls, and they must overcome physical confinement to grow to specific sizes and shapes. Cell wall tension and turgor pressure are the main mechanical components impacting plant cell growth. Cell wall mechanics has been the focus of most plant biomechanical studies, and turgor pressure was often considered as a constant and largely passive component. Nevertheless, it is increasingly accepted that turgor pressure plays a significant role in plant growth. Numerous theoretical and experimental studies suggest that turgor pressure can be both spatially inhomogeneous and actively modulated during morphogenesis. Here, we revisit the pressure-growth relationship by reviewing recent advances in investigating the interactions between cellular/tissular pressure and growth.
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Affiliation(s)
- Olivier Ali
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, Lyon Cedex 07, 69364, France
| | - Ibrahim Cheddadi
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, Lyon Cedex 07, 69364, France
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Benoit Landrein
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, Lyon Cedex 07, 69364, France
| | - Yuchen Long
- Department of Biological Sciences, The National University of Singapore, Singapore, 117543, Singapore
- Mechanobiology Institute, The National University of Singapore, Singapore, 117411, Singapore
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13
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Xia Z, Wen B, Shao J, Zhang T, Hu M, Lin L, Zheng Y, Shi Z, Dong X, Song J, Li Y, Wu Y, Yuan Y, Wu J, Chen Q, Chen J. The transcription factor PbrbZIP52 positively affects pear pollen tube longevity by promoting callose synthesis. PLANT PHYSIOLOGY 2023; 191:1734-1750. [PMID: 36617219 PMCID: PMC10022607 DOI: 10.1093/plphys/kiad002] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
In pear (Pyrus bretschneideri), pollen tube growth is critical for the double fertilization associated with seed setting, which in turn affects fruit yield. The normal deposition of callose mediates the polar growth of pollen tubes. However, the mechanism regulating callose synthesis in pollen tubes remains relatively uncharacterized. In this study, we revealed that the typical pear pollen tube lifecycle has a semi-growth duration (GD50) of 16.16 h under in vitro culture conditions. Moreover, callose plugs were deposited throughout the pollen tube lifecycle. The formation of callose plugs was inhibited by 2-deoxy-D-glucose, which also accelerated the senescence of pear pollen tubes. Additionally, PbrCalS1B.1, which encodes a plasma membrane-localized callose synthase, was expressed specifically in pollen tubes and restored the fertility of the Arabidopsis (Arabidopsis thaliana) cals5 mutant, in which callose synthesis is inhibited. However, this restoration of fertility was impaired by the transient silencing of PbrCalS1B.1, which restricts callose plug formation and shortens the pear pollen tube lifecycle. More specifically, PbrbZIP52 regulated PbrCalS1B.1 transcription by binding to promoter A-box elements to maintain the periodic formation of callose plugs and normal pollen tube growth, ultimately leading to double fertilization. This study confirmed that PbrbZIP52 positively affects pear pollen tube longevity by promoting callose synthesis. This finding may be useful for breeding high-yielding pear cultivars and stabilizing fruit setting in commercial orchards.
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Affiliation(s)
- Zhongheng Xia
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Binxu Wen
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jing Shao
- Institute of Pomology, Jilin Academy of Agricultural Sciences, Gongzhuling 136100, China
| | - Tianci Zhang
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Mengmeng Hu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lin Lin
- Anxi College of Tea Science, Fujian Agriculture and Forestry University, Anxi 362406, China
| | - Yiping Zheng
- Fujian Academy of Agricultural Sciences Biotechnology Institute, Fuzhou 350003, China
| | - Zhixin Shi
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xinlin Dong
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Juanjuan Song
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yuanshan Li
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yongjie Wu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yafang Yuan
- Department of Horticulture and Landscape Architecture, Fujian Vocational College of Agriculture, Fuzhou 350119, China
| | - Juyou Wu
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Qingxi Chen
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jianqing Chen
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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14
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Etale A, Onyianta AJ, Turner SR, Eichhorn SJ. Cellulose: A Review of Water Interactions, Applications in Composites, and Water Treatment. Chem Rev 2023; 123:2016-2048. [PMID: 36622272 PMCID: PMC9999429 DOI: 10.1021/acs.chemrev.2c00477] [Citation(s) in RCA: 81] [Impact Index Per Article: 81.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cellulose is known to interact well with water, but is insoluble in it. Many polysaccharides such as cellulose are known to have significant hydrogen bond networks joining the molecular chains, and yet they are recalcitrant to aqueous solvents. This review charts the interaction of cellulose with water but with emphasis on the formation of both natural and synthetic fiber composites. Covering studies concerning the interaction of water with wood, the biosynthesis of cellulose in the cell wall, to its dispersion in aqueous suspensions and ultimately in water filtration and fiber-based composite materials this review explores water-cellulose interactions and how they can be exploited for synthetic and natural composites. The suggestion that cellulose is amphiphilic is critically reviewed, with relevance to its processing. Building on this, progress made in using various charged and modified forms of nanocellulose to stabilize oil-water emulsions is addressed. The role of water in the aqueous formation of chiral nematic liquid crystals, and subsequently when dried into composite films is covered. The review will also address the use of cellulose as an aid to water filtration as one area where interactions can be used effectively to prosper human life.
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Affiliation(s)
- Anita Etale
- Bristol Composites Institute, School of Civil, Aerospace and Mechanical Engineering, University of Bristol, University Walk, BristolBS8 1TR, United Kingdom
| | - Amaka J Onyianta
- Bristol Composites Institute, School of Civil, Aerospace and Mechanical Engineering, University of Bristol, University Walk, BristolBS8 1TR, United Kingdom
| | - Simon R Turner
- School of Biological Science, University of Manchester, Oxford Road, ManchesterM13 9PT, U.K
| | - Stephen J Eichhorn
- Bristol Composites Institute, School of Civil, Aerospace and Mechanical Engineering, University of Bristol, University Walk, BristolBS8 1TR, United Kingdom
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15
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Yan H, Zhuang M, Xu X, Li S, Yang M, Li N, Du X, Hu K, Peng X, Huang W, Wu H, Tse YC, Zhao L, Wang H. Autophagy and its mediated mitochondrial quality control maintain pollen tube growth and male fertility in Arabidopsis. Autophagy 2023; 19:768-783. [PMID: 35786359 PMCID: PMC9980518 DOI: 10.1080/15548627.2022.2095838] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Macroautophagy/autophagy, a major catabolic pathway in eukaryotes, participates in plant sexual reproduction including the processes of male gametogenesis and the self-incompatibility response. Rapid pollen tube growth is another essential reproductive process that is metabolically highly demanding to drive the vigorous cell growth for delivery of male gametes for fertilization in angiosperms. Whether and how autophagy operates to maintain the homeostasis of pollen tubes remains unknown. Here, we provide evidence that autophagy is elevated in growing pollen tubes and critically required during pollen tube growth and male fertility in Arabidopsis. We demonstrate that SH3P2, a critical non-ATG regulator of plant autophagy, colocalizes with representative ATG proteins during autophagosome biogenesis in growing pollen tubes. Downregulation of SH3P2 expression significantly disrupts Arabidopsis pollen germination and pollen tube growth. Further analysis of organelle dynamics reveals crosstalk between autophagosomes and prevacuolar compartments following the inhibition of phosphatidylinositol 3-kinase. In addition, time-lapse imaging and tracking of ATG8e-labeled autophagosomes and depolarized mitochondria demonstrate that they interact specifically via the ATG8-family interacting motif (AIM)-docking site to mediate mitophagy. Ultrastructural identification of mitophagosomes and two additional forms of autophagosomes imply that multiple types of autophagy are likely to function simultaneously within pollen tubes. Altogether, our results suggest that autophagy is functionally crucial for mediating mitochondrial quality control and canonical cytoplasm recycling during pollen tube growth.Abbreviations: AIM: ATG8-family interacting motif; ATG8: autophagy related 8; ATG5: autophagy related 5; ATG7: autophagy related 7; BTH: acibenzolar-S-methyl; DEX: dexamethasone; DNP: 2,4-dinitrophenol; GFP: green fluorescent protein; YFP: yellow fluorescent protein; PtdIns3K: phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PVC: prevacuolar compartment; SH3P2: SH3 domain-containing protein 2.
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Affiliation(s)
- He Yan
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Menglong Zhuang
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Xiaoyu Xu
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Shanshan Li
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Mingkang Yang
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou null China
| | - Nianle Li
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Xiaojuan Du
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Kangwei Hu
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Xiaomin Peng
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Wei Huang
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou null China
| | - Hong Wu
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou null China
| | - Yu Chung Tse
- Core Research Facilities, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Lifeng Zhao
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Hao Wang
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
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16
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Zhao F, Long Y. Mechanosensing, from forces to structures. FRONTIERS IN PLANT SCIENCE 2022; 13:1060018. [PMID: 36531357 PMCID: PMC9751800 DOI: 10.3389/fpls.2022.1060018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
Sessile plants evolve diverse structures in response to complex environmental cues. These factors, in essence, involve mechanical stimuli, which must be sensed and coordinated properly by the plants to ensure effective growth and development. While we have accumulated substantial knowledge on plant mechanobiology, how plants translate mechanical information into three-dimensional structures is still an open question. In this review, we summarize our current understanding of plant mechanosensing at different levels, particularly using Arabidopsis as a model plant system. We also attempt to abstract the mechanosensing process and link the gaps from mechanical cues to the generation of complex plant structures. Here we review the recent advancements on mechanical response and transduction in plant morphogenesis, and we also raise several questions that interest us in different sections.
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Affiliation(s)
- Feng Zhao
- Collaborative Innovation Center of Northwestern Polytechnical University, Shanghai, China
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Yuchen Long
- Department of Biological Sciences, The National University of Singapore, Singapore, Singapore
- Mechanobiology Institute, The National University of Singapore, Singapore, Singapore
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17
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Weng X, Wang H. Apical vesicles: Social networking at the pollen tube tip. REPRODUCTION AND BREEDING 2022. [DOI: 10.1016/j.repbre.2022.11.001] [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] Open
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18
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Municio-Diaz C, Muller E, Drevensek S, Fruleux A, Lorenzetti E, Boudaoud A, Minc N. Mechanobiology of the cell wall – insights from tip-growing plant and fungal cells. J Cell Sci 2022; 135:280540. [DOI: 10.1242/jcs.259208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ABSTRACT
The cell wall (CW) is a thin and rigid layer encasing the membrane of all plant and fungal cells. It ensures mechanical integrity by bearing mechanical stresses derived from large cytoplasmic turgor pressure, contacts with growing neighbors or growth within restricted spaces. The CW is made of polysaccharides and proteins, but is dynamic in nature, changing composition and geometry during growth, reproduction or infection. Such continuous and often rapid remodeling entails risks of enhanced stress and consequent damages or fractures, raising the question of how the CW detects and measures surface mechanical stress and how it strengthens to ensure surface integrity? Although early studies in model fungal and plant cells have identified homeostatic pathways required for CW integrity, recent methodologies are now allowing the measurement of pressure and local mechanical properties of CWs in live cells, as well as addressing how forces and stresses can be detected at the CW surface, fostering the emergence of the field of CW mechanobiology. Here, using tip-growing cells of plants and fungi as case study models, we review recent progress on CW mechanosensation and mechanical regulation, and their implications for the control of cell growth, morphogenesis and survival.
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Affiliation(s)
- Celia Municio-Diaz
- Université de Paris, CNRS, Institut Jacques Monod 1 , F-75006 Paris , France
- Equipe Labellisée LIGUE Contre le Cancer 2 , 75013 Paris , France
| | - Elise Muller
- LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris 3 , 91128 Palaiseau Cedex , France
| | - Stéphanie Drevensek
- LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris 3 , 91128 Palaiseau Cedex , France
| | - Antoine Fruleux
- LPTMS, CNRS, Université Paris-Saclay 4 , 91405 Orsay , France
| | - Enrico Lorenzetti
- LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris 3 , 91128 Palaiseau Cedex , France
| | - Arezki Boudaoud
- LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris 3 , 91128 Palaiseau Cedex , France
| | - Nicolas Minc
- Université de Paris, CNRS, Institut Jacques Monod 1 , F-75006 Paris , France
- Equipe Labellisée LIGUE Contre le Cancer 2 , 75013 Paris , France
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19
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Damineli DSC, Portes MT, Feijó JA. Electrifying rhythms in plant cells. Curr Opin Cell Biol 2022; 77:102113. [PMID: 35809387 DOI: 10.1016/j.ceb.2022.102113] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 05/10/2022] [Accepted: 06/05/2022] [Indexed: 12/12/2022]
Abstract
Physiological oscillations (or rhythms) pervade all spatiotemporal scales of biological organization, either because they perform critical functions or simply because they can arise spontaneously and may be difficult to prevent. Regardless of the case, they reflect regulatory relationships between control points of a given system and offer insights as read-outs of the concerted regulation of a myriad of biological processes. Here we review recent advances in understanding ultradian oscillations (period < 24h) in plant cells, with a special focus on single-cell oscillations. Ion channels are at the center stage due to their involvement in electrical/excitabile phenomena associated with oscillations and cell-cell communication. We highlight the importance of quantitative approaches to measure oscillations in appropriate physiological conditions, which are essential strategies to deal with the complexity of biological rhythms. Future development of optogenetics techniques in plants will further boost research on the role of membrane potential in oscillations and waves across multiple cell types.
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Affiliation(s)
- Daniel S C Damineli
- Department of Computer Science, Institute of Mathematics and Statistics, University of São Paulo, São Paulo, SP 05508-090, Brazil.
| | - Maria Teresa Portes
- Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, SP 05508-090, Brazil
| | - José A Feijó
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742-5815, USA
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20
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Cosgrove DJ. Building an extensible cell wall. PLANT PHYSIOLOGY 2022; 189:1246-1277. [PMID: 35460252 PMCID: PMC9237729 DOI: 10.1093/plphys/kiac184] [Citation(s) in RCA: 80] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/21/2022] [Indexed: 05/15/2023]
Abstract
This article recounts, from my perspective of four decades in this field, evolving paradigms of primary cell wall structure and the mechanism of surface enlargement of growing cell walls. Updates of the structures, physical interactions, and roles of cellulose, xyloglucan, and pectins are presented. This leads to an example of how a conceptual depiction of wall structure can be translated into an explicit quantitative model based on molecular dynamics methods. Comparison of the model's mechanical behavior with experimental results provides insights into the molecular basis of complex mechanical behaviors of primary cell wall and uncovers the dominant role of cellulose-cellulose interactions in forming a strong yet extensible network.
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Affiliation(s)
- Daniel J Cosgrove
- Department of Biology, Penn State University, Pennsylvania 16802, USA
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21
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Bronkhorst J, Kots K, de Jong D, Kasteel M, van Boxmeer T, Joemmanbaks T, Govers F, van der Gucht J, Ketelaar T, Sprakel J. An actin mechanostat ensures hyphal tip sharpness in Phytophthora infestans to achieve host penetration. SCIENCE ADVANCES 2022; 8:eabo0875. [PMID: 35687685 PMCID: PMC9187236 DOI: 10.1126/sciadv.abo0875] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 04/25/2022] [Indexed: 05/31/2023]
Abstract
Filamentous plant pathogens apply mechanical forces to pierce their hosts surface and penetrate its tissues. Devastating Phytophthora pathogens harness a specialized form of invasive tip growth to slice through the plant surface, wielding their hypha as a microscopic knife. Slicing requires a sharp hyphal tip that is not blunted at the site of the mechanical interaction. How tip shape is controlled, however, is unknown. We uncover an actin-based mechanostat in Phytophthora infestans that controls tip sharpness during penetration. Mechanical stimulation of the hypha leads to the emergence of an aster-like actin configuration, which shows fast, local, and quantitative feedback to the local stress. We evidence that this functions as an adaptive mechanical scaffold that sharpens the invasive weapon and prevents it from blunting. The hyphal tip mechanostat enables the efficient conversion of turgor into localized invasive pressures that are required to achieve host penetration.
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Affiliation(s)
- Jochem Bronkhorst
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, Netherlands
| | - Kiki Kots
- Laboratory of Phytopathology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands
- Laboratory of Cell Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands
| | - Djanick de Jong
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, Netherlands
| | - Michiel Kasteel
- Laboratory of Phytopathology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands
- Laboratory of Cell Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands
| | - Thomas van Boxmeer
- Laboratory of Cell Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands
| | - Tanweer Joemmanbaks
- Laboratory of Cell Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands
| | - Francine Govers
- Laboratory of Phytopathology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands
| | - Jasper van der Gucht
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, Netherlands
| | - Tijs Ketelaar
- Laboratory of Cell Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands
| | - Joris Sprakel
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, Netherlands
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, Netherlands
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22
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Miller K, Strychalski W, Nickaeen M, Carlsson A, Haswell ES. In vitro experiments and kinetic models of Arabidopsis pollen hydration mechanics show that MSL8 is not a simple tension-gated osmoregulator. Curr Biol 2022; 32:2921-2934.e3. [PMID: 35660140 DOI: 10.1016/j.cub.2022.05.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/12/2022] [Accepted: 05/12/2022] [Indexed: 10/18/2022]
Abstract
Pollen, a neighbor-less cell containing the male gametes, undergoes mechanical challenges during plant sexual reproduction, including desiccation and rehydration. It was previously shown that the pollen-specific mechanosensitive ion channel MscS-like (MSL)8 is essential for pollen survival during hydration and proposed that it functions as a tension-gated osmoregulator. Here, we test this hypothesis with a combination of mathematical modeling and laboratory experiments. Time-lapse imaging revealed that wild-type pollen grains swell, and then they stabilize in volume rapidly during hydration. msl8 mutant pollen grains, however, continue to expand and eventually burst. We found that a mathematical model, wherein MSL8 acts as a simple-tension-gated osmoregulator, does not replicate this behavior. A better fit was obtained from variations of the model, wherein MSL8 inactivates independent of its membrane tension gating threshold or MSL8 strengthens the cell wall without osmotic regulation. Experimental and computational testing of several perturbations, including hydration in an osmolyte-rich solution, hyper-desiccation of the grains, and MSL8-YFP overexpression, indicated that the cell wall strengthening model best simulated experimental responses. Finally, the expression of a nonconducting MSL8 variant did not complement the msl8 overexpansion phenotype. These data indicate that contrary to our hypothesis and to the current understanding of MS ion channel function in bacteria, MSL8 does not act as a simple membrane tension-gated osmoregulator. Instead, they support a model wherein ion flux through MSL8 is required to alter pollen cell wall properties. These results demonstrate the utility of pollen as a cellular scale model system and illustrate how mathematical models can correct intuitive hypotheses.
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Affiliation(s)
- Kari Miller
- Department of Biology, Washington University, St. Louis, MO 63130, USA; NSF Center for Engineering Mechanobiology, Cleveland, OH, USA
| | - Wanda Strychalski
- Department of Mathematics, Applied Mathematics, and Statistics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Masoud Nickaeen
- University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Anders Carlsson
- NSF Center for Engineering Mechanobiology, Cleveland, OH, USA; Department of Physics, Washington University, St. Louis, MO 63130, USA
| | - Elizabeth S Haswell
- Department of Biology, Washington University, St. Louis, MO 63130, USA; NSF Center for Engineering Mechanobiology, Cleveland, OH, USA.
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