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Rafińska K, Niedojadło K, Świdziński M, Bednarska-Kozakiewicz E. Distribution of exchangeable Ca 2+ during the process of Larix decidua Mill. pollination and germination. Sci Rep 2024; 14:5639. [PMID: 38454044 PMCID: PMC10920793 DOI: 10.1038/s41598-024-54903-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 02/18/2024] [Indexed: 03/09/2024] Open
Abstract
The involvement of Ca2+ ions in angiosperms sexual processes is well established, while in gymnosperms, such knowledge remains limited and is still a topic of discussion. In this study, we focused on Larix decidua, using Alizarin-red S staining and the pyroantimonate method to examine the tissue and subcellular distribution of free and loosely bound Ca2+ ions at different stages of the male gametophyte's development and its interaction with the ovule. Our findings show that in larch, both the germination of pollen grains and the growth of pollen tubes occur in an environment rich in Ca2+. These ions play a crucial role in the adhesion of the pollen grain to the stigmatic tip and its subsequent movement to the micropylar canal. There is a significant presence of free and loosely bound Ca2+ ions in both the fluid of the micropylar canal and the extracellular matrix of the nucellus. As the pollen tube extends through the nucellus, we observed a notable accumulation of Ca2+ ions just above the entry to the mature archegonium, a region likely crucial for the male gametophyte's directional growth. Meanwhile, the localized presence of free and loosely bound Ca2+ ions within the egg cell cytoplasm may inhibit the pollen tubes growth and rupture, playing an important role in fertilization.
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Affiliation(s)
- Katarzyna Rafińska
- Department of Environmental Chemistry and Bioanalysis, Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, 87-100, Toruń, Poland
| | - Katarzyna Niedojadło
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100, Toruń, Poland.
| | - Michał Świdziński
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100, Toruń, Poland
| | - Elżbieta Bednarska-Kozakiewicz
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100, Toruń, Poland
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2
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Expression of Clementine Asp-Rich Proteins (CcASP-RICH) in Tobacco Plants Interferes with the Mechanism of Pollen Tube Growth. Int J Mol Sci 2022; 23:ijms23147880. [PMID: 35887233 PMCID: PMC9316813 DOI: 10.3390/ijms23147880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 11/29/2022] Open
Abstract
Low-molecular-weight, aspartic-acid-rich proteins (ASP-RICH) have been assumed to be involved in the self-incompatibility process of clementine. The role of ASP-RICH is not known, but hypothetically they could sequester calcium ions (Ca2+) and affect Ca2+-dependent mechanisms. In this article, we analyzed the effects induced by clementine ASP-RICH proteins (CcASP-RICH) when expressed in the tobacco heterologous system, focusing on the male gametophyte. The aim was to gain insight into the mechanism of action of ASP-RICH in a well-known cellular system, i.e., the pollen tube. Pollen tubes of tobacco transgenic lines expressing CcASP-RICH were analyzed for Ca2+ distribution, ROS, proton gradient, as well as cytoskeleton and cell wall. CcASP-RICH modulated Ca2+ content and consequently affected cytoskeleton organization and the deposition of cell wall components. In turn, this affected the growth pattern of pollen tubes. Although the expression of CcASP-RICH did not exert a remarkable effect on the growth rate of pollen tubes, effects at the level of growth pattern suggest that the expression of ASP-RICH may exert a regulatory action on the mechanism of plant cell growth.
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3
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Çetinbaş-Genç A, Conti V, Cai G. Let's shape again: the concerted molecular action that builds the pollen tube. PLANT REPRODUCTION 2022; 35:77-103. [PMID: 35041045 DOI: 10.1007/s00497-022-00437-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
The pollen tube is being subjected to control by a complex network of communication that regulates its shape and the misfunction of a single component causes specific deformations. In flowering plants, the pollen tube is a tubular extension of the pollen grain required for successful sexual reproduction. Indeed, maintaining the unique shape of the pollen tube is essential for the pollen tube to approach the embryo sac. Many processes and molecules (such as GTPase activity, phosphoinositides, Ca2+ gradient, distribution of reactive oxygen species and nitric oxide, nonuniform pH values, organization of the cytoskeleton, balance between exocytosis and endocytosis, and cell wall structure) play key and coordinated roles in maintaining the cylindrical shape of pollen tubes. In addition, the above factors must also interact with each other so that the cell shape is maintained while the pollen tube follows chemical signals in the pistil that guide it to the embryo sac. Any intrinsic changes (such as erroneous signals) or extrinsic changes (such as environmental stresses) can affect the above factors and thus fertilization by altering the tube morphology. In this review, the processes and molecules that enable the development and maintenance of the unique shape of pollen tubes in angiosperms are presented emphasizing their interaction with specific tube shape. Thus, the purpose of the review is to investigate whether specific deformations in pollen tubes can help us to better understand the mechanism underlying pollen tube shape.
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Affiliation(s)
- Aslıhan Çetinbaş-Genç
- Department of Biology, Marmara University, Göztepe Campus, 34722, Kadıköy, Istanbul, Turkey.
| | - Veronica Conti
- Department of Life Sciences, University of Siena, via Mattioli 4, 53100, Siena, Italy
| | - Giampiero Cai
- Department of Life Sciences, University of Siena, via Mattioli 4, 53100, Siena, Italy
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4
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Guo J, He J, Dehesh K, Cui X, Yang Z. CamelliA-based simultaneous imaging of Ca2+ dynamics in subcellular compartments. PLANT PHYSIOLOGY 2022; 188:2253-2271. [PMID: 35218352 PMCID: PMC8968278 DOI: 10.1093/plphys/kiac020] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
As a universal second messenger, calcium (Ca2+) transmits specific cellular signals via a spatiotemporal signature generated from its extracellular source and internal stores. Our knowledge of the mechanisms underlying the generation of a Ca2+ signature is hampered by limited tools for simultaneously monitoring dynamic Ca2+ levels in multiple subcellular compartments. To overcome the limitation and to further improve spatiotemporal resolutions, we have assembled a molecular toolset (CamelliA lines) in Arabidopsis (Arabidopsis thaliana) that enables simultaneous and high-resolution monitoring of Ca2+ dynamics in multiple subcellular compartments through imaging different single-colored genetically encoded calcium indicators. We uncovered several Ca2+ signatures in three types of Arabidopsis cells in response to internal and external cues, including rapid oscillations of cytosolic Ca2+ and apical plasma membrane Ca2+ influx in fast-growing Arabidopsis pollen tubes, the spatiotemporal relationship of Ca2+ dynamics in four subcellular compartments of root epidermal cells challenged with salt, and a shockwave-like Ca2+ wave propagating in laser-wounded leaf epidermis. These observations serve as a testimony to the wide applicability of the CamelliA lines for elucidating the subcellular sources contributing to the Ca2+ signatures in plants.
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Affiliation(s)
- Jingzhe Guo
- Institute for Integrative Genome Biology, University of California, Riverside, 92521 California, USA
- Department of Botany and Plant Sciences, University of California, Riverside, 92521 California, USA
| | - Jiangman He
- Institute for Integrative Genome Biology, University of California, Riverside, 92521 California, USA
- Department of Botany and Plant Sciences, University of California, Riverside, 92521 California, USA
| | - Katayoon Dehesh
- Institute for Integrative Genome Biology, University of California, Riverside, 92521 California, USA
- Department of Botany and Plant Sciences, University of California, Riverside, 92521 California, USA
| | - Xinping Cui
- Institute for Integrative Genome Biology, University of California, Riverside, 92521 California, USA
- Department of Statistics, University of California, Riverside, 92521 California, USA
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5
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Resentini F, Ruberti C, Grenzi M, Bonza MC, Costa A. The signatures of organellar calcium. PLANT PHYSIOLOGY 2021; 187:1985-2004. [PMID: 33905517 PMCID: PMC8644629 DOI: 10.1093/plphys/kiab189] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/10/2021] [Indexed: 05/23/2023]
Abstract
Recent insights about the transport mechanisms involved in the in and out of calcium ions in plant organelles, and their role in the regulation of cytosolic calcium homeostasis in different signaling pathways.
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Affiliation(s)
| | - Cristina Ruberti
- Department of Biosciences, University of Milan, Milano 20133, Italy
| | - Matteo Grenzi
- Department of Biosciences, University of Milan, Milano 20133, Italy
| | | | - Alex Costa
- Department of Biosciences, University of Milan, Milano 20133, Italy
- Institute of Biophysics, National Research Council of Italy (CNR), Milano 20133, Italy
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6
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Resentini F, Grenzi M, Ancora D, Cademartori M, Luoni L, Franco M, Bassi A, Bonza MC, Costa A. Simultaneous imaging of ER and cytosolic Ca2+ dynamics reveals long-distance ER Ca2+ waves in plants. PLANT PHYSIOLOGY 2021; 187:603-617. [PMID: 34608947 PMCID: PMC8491065 DOI: 10.1093/plphys/kiab251] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/12/2021] [Indexed: 05/07/2023]
Abstract
Calcium ions (Ca2+) play a key role in cell signaling across organisms. In plants, a plethora of environmental and developmental stimuli induce specific Ca2+ increases in the cytosol as well as in different cellular compartments including the endoplasmic reticulum (ER). The ER represents an intracellular Ca2+ store that actively accumulates Ca2+ taken up from the cytosol. By exploiting state-of-the-art genetically encoded Ca2+ indicators, specifically the ER-GCaMP6-210 and R-GECO1, we report the generation and characterization of an Arabidopsis (Arabidopsis thaliana) line that allows for simultaneous imaging of Ca2+ dynamics in both the ER and cytosol at different spatial scales. By performing analyses in single cells, we precisely quantified (1) the time required by the ER to import Ca2+ from the cytosol into the lumen and (2) the time required to observe a cytosolic Ca2+ increase upon the pharmacological inhibition of the ER-localized P-Type IIA Ca2+-ATPases. Furthermore, live imaging of mature, soil-grown plants revealed the existence of a wounding-induced, long-distance ER Ca2+ wave propagating in injured and systemic rosette leaves. This technology enhances high-resolution analyses of intracellular Ca2+ dynamics at the cellular level and in adult organisms and paves the way to develop new methodologies aimed at defining the contribution of subcellular compartments in Ca2+ homeostasis and signaling.
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Affiliation(s)
| | - Matteo Grenzi
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Daniele Ancora
- Department of Physics, Politecnico di Milano, Milan 20133, Italy
| | - Mara Cademartori
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Laura Luoni
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Marianna Franco
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Andrea Bassi
- Department of Physics, Politecnico di Milano, Milan 20133, Italy
| | | | - Alex Costa
- Department of Biosciences, University of Milan, Milan 20133, Italy
- Institute of Biophysics, Consiglio Nazionale Delle Ricerche, Milan 20133, Italy
- Author for communication:
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7
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Grenzi M, Resentini F, Vanneste S, Zottini M, Bassi A, Costa A. Illuminating the hidden world of calcium ions in plants with a universe of indicators. PLANT PHYSIOLOGY 2021; 187:550-571. [PMID: 35237821 PMCID: PMC8491032 DOI: 10.1093/plphys/kiab339] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 07/15/2021] [Indexed: 05/20/2023]
Abstract
The tools available to carry out in vivo analysis of Ca2+ dynamics in plants are powerful and mature technologies that still require the proper controls.
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Affiliation(s)
- Matteo Grenzi
- Department of Biosciences, University of Milan, 20133 Milano, Italy
| | | | - Steffen Vanneste
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Department of Plants and Crops, Ghent University, 9000 Ghent, Belgium
- Laboratory of Plant Growth Analysis, Ghent University Global Campus, Incheon 21985, South Korea
| | - Michela Zottini
- Department of Biology, University of Padova, 35131 Padova, Italy
| | - Andrea Bassi
- Department of Physics, Politecnico di Milano, 20133 Milano, Italy
- Institute of Photonics and Nanotechnologies, National Research Council of Italy (CNR), 20133 Milano, Italy
| | - Alex Costa
- Department of Biosciences, University of Milan, 20133 Milano, Italy
- Institute of Biophysics, National Research Council of Italy (CNR), 20133 Milano, Italy
- Author for communication:
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8
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Deciphering the Role of Ion Channels in Early Defense Signaling against Herbivorous Insects. Cells 2021; 10:cells10092219. [PMID: 34571868 PMCID: PMC8470099 DOI: 10.3390/cells10092219] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 12/14/2022] Open
Abstract
Plants and insect herbivores are in a relentless battle to outwit each other. Plants have evolved various strategies to detect herbivores and mount an effective defense system against them. These defenses include physical and structural barriers such as spines, trichomes, cuticle, or chemical compounds, including secondary metabolites such as phenolics and terpenes. Plants perceive herbivory by both mechanical and chemical means. Mechanical sensing can occur through the perception of insect biting, piercing, or chewing, while chemical signaling occurs through the perception of various herbivore-derived compounds such as oral secretions (OS) or regurgitant, insect excreta (frass), or oviposition fluids. Interestingly, ion channels or transporters are the first responders for the perception of these mechanical and chemical cues. These transmembrane pore proteins can play an important role in plant defense through the induction of early signaling components such as plasma transmembrane potential (Vm) fluctuation, intracellular calcium (Ca2+), and reactive oxygen species (ROS) generation, followed by defense gene expression, and, ultimately, plant defense responses. In recent years, studies on early plant defense signaling in response to herbivory have been gaining momentum with the application of genetically encoded GFP-based sensors for real-time monitoring of early signaling events and genetic tools to manipulate ion channels involved in plant-herbivore interactions. In this review, we provide an update on recent developments and advances on early signaling events in plant-herbivore interactions, with an emphasis on the role of ion channels in early plant defense signaling.
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9
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Li K, Prada J, Damineli DSC, Liese A, Romeis T, Dandekar T, Feijó JA, Hedrich R, Konrad KR. An optimized genetically encoded dual reporter for simultaneous ratio imaging of Ca 2+ and H + reveals new insights into ion signaling in plants. THE NEW PHYTOLOGIST 2021; 230:2292-2310. [PMID: 33455006 PMCID: PMC8383442 DOI: 10.1111/nph.17202] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/23/2020] [Indexed: 05/07/2023]
Abstract
Whereas the role of calcium ions (Ca2+ ) in plant signaling is well studied, the physiological significance of pH-changes remains largely undefined. Here we developed CapHensor, an optimized dual-reporter for simultaneous Ca2+ and pH ratio-imaging and studied signaling events in pollen tubes (PTs), guard cells (GCs), and mesophyll cells (MCs). Monitoring spatio-temporal relationships between membrane voltage, Ca2+ - and pH-dynamics revealed interconnections previously not described. In tobacco PTs, we demonstrated Ca2+ -dynamics lag behind pH-dynamics during oscillatory growth, and pH correlates more with growth than Ca2+ . In GCs, we demonstrated abscisic acid (ABA) to initiate stomatal closure via rapid cytosolic alkalization followed by Ca2+ elevation. Preventing the alkalization blocked GC ABA-responses and even opened stomata in the presence of ABA, disclosing an important pH-dependent GC signaling node. In MCs, a flg22-induced membrane depolarization preceded Ca2+ -increases and cytosolic acidification by c. 2 min, suggesting a Ca2+ /pH-independent early pathogen signaling step. Imaging Ca2+ and pH resolved similar cytosol and nuclear signals and demonstrated flg22, but not ABA and hydrogen peroxide to initiate rapid membrane voltage-, Ca2+ - and pH-responses. We propose close interrelation in Ca2+ - and pH-signaling that is cell type- and stimulus-specific and the pH having crucial roles in regulating PT growth and stomata movement.
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Affiliation(s)
- Kunkun Li
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, Wuerzburg 97082, Germany
| | - Juan Prada
- Department of Bioinformatics, University of Wuerzburg, Wuerzburg 97074, Germany
| | - Daniel S. C. Damineli
- Department of Cell Biology & Molecular Genetics, University of Maryland, 2136 Bioscience Research Bldg, College Park, MD 20742-5815, USA
- Department of Pediatrics, Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP 01246-903, Brazil
| | - Anja Liese
- Leibniz Institute of Plant Biochemistry, Halle (Saale) 06120, Germany
| | - Tina Romeis
- Leibniz Institute of Plant Biochemistry, Halle (Saale) 06120, Germany
| | - Thomas Dandekar
- Department of Bioinformatics, University of Wuerzburg, Wuerzburg 97074, Germany
| | - José A. Feijó
- Department of Cell Biology & Molecular Genetics, University of Maryland, 2136 Bioscience Research Bldg, College Park, MD 20742-5815, USA
| | - Rainer Hedrich
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, Wuerzburg 97082, Germany
| | - Kai Robert Konrad
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, Wuerzburg 97082, Germany
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Hayashi M, Palmgren M. The quest for the central players governing pollen tube growth and guidance. PLANT PHYSIOLOGY 2021; 185:682-693. [PMID: 33793904 PMCID: PMC8133568 DOI: 10.1093/plphys/kiaa092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 12/06/2020] [Indexed: 05/02/2023]
Abstract
Recent insights into the mechanism of pollen tube growth and guidance point to the importance of H+ dynamics, which are regulated by the plasma membrane H+-ATPase.
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Affiliation(s)
- Maki Hayashi
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
| | - Michael Palmgren
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000,China
- Author for communication:
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11
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Ruan H, Li J, Wang T, Ren H. Secretory Vesicles Targeted to Plasma Membrane During Pollen Germination and Tube Growth. Front Cell Dev Biol 2021; 8:615447. [PMID: 33553150 PMCID: PMC7859277 DOI: 10.3389/fcell.2020.615447] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/14/2020] [Indexed: 12/12/2022] Open
Abstract
Pollen germination and pollen tube growth are important biological events in the sexual reproduction of higher plants, during which a large number of vesicle trafficking and membrane fusion events occur. When secretory vesicles are transported via the F-actin network in proximity to the apex of the pollen tube, the secretory vesicles are tethered and fused to the plasma membrane by tethering factors and SNARE proteins, respectively. The coupling and uncoupling between the vesicle membrane and plasma membrane are also regulated by dynamic cytoskeleton, proteins, and signaling molecules, including small G proteins, calcium, and PIP2. In this review, we focus on the current knowledge regarding secretory vesicle delivery, tethering, and fusion during pollen germination and tube growth and summarize the progress in research on how regulators and signaling molecules participate in the above processes.
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Affiliation(s)
- Huaqiang Ruan
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
| | - Jiang Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
| | - Ting Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
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12
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Xu Y, Huang S. Control of the Actin Cytoskeleton Within Apical and Subapical Regions of Pollen Tubes. Front Cell Dev Biol 2020; 8:614821. [PMID: 33344460 PMCID: PMC7744591 DOI: 10.3389/fcell.2020.614821] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/13/2020] [Indexed: 01/07/2023] Open
Abstract
In flowering plants, sexual reproduction involves a double fertilization event, which is facilitated by the delivery of two non-motile sperm cells to the ovule by the pollen tube. Pollen tube growth occurs exclusively at the tip and is extremely rapid. It strictly depends on an intact actin cytoskeleton, and is therefore an excellent model for uncovering the molecular mechanisms underlying dynamic actin cytoskeleton remodeling. There has been a long-term debate about the organization and dynamics of actin filaments within the apical and subapical regions of pollen tube tips. By combining state-of-the-art live-cell imaging with the usage of mutants which lack different actin-binding proteins, our understanding of the origin, spatial organization, dynamics and regulation of actin filaments within the pollen tube tip has greatly improved. In this review article, we will summarize the progress made in this area.
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Affiliation(s)
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
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13
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Dietrich P, Moeder W, Yoshioka K. Plant Cyclic Nucleotide-Gated Channels: New Insights on Their Functions and Regulation. PLANT PHYSIOLOGY 2020; 184:27-38. [PMID: 32576644 PMCID: PMC7479878 DOI: 10.1104/pp.20.00425] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/17/2020] [Indexed: 05/02/2023]
Abstract
Recent advances of plant cyclic nucleotide-gated channels give new insight into their molecular functions focusing on regulation, subunit assembly, and phosphorylation.
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Affiliation(s)
- Petra Dietrich
- Molecular Plant Physiology, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Wolfgang Moeder
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
| | - Keiko Yoshioka
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Center for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
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14
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Scholz P, Anstatt J, Krawczyk HE, Ischebeck T. Signalling Pinpointed to the Tip: The Complex Regulatory Network That Allows Pollen Tube Growth. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1098. [PMID: 32859043 PMCID: PMC7569787 DOI: 10.3390/plants9091098] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/18/2020] [Accepted: 08/23/2020] [Indexed: 12/13/2022]
Abstract
Plants display a complex life cycle, alternating between haploid and diploid generations. During fertilisation, the haploid sperm cells are delivered to the female gametophyte by pollen tubes, specialised structures elongating by tip growth, which is based on an equilibrium between cell wall-reinforcing processes and turgor-driven expansion. One important factor of this equilibrium is the rate of pectin secretion mediated and regulated by factors including the exocyst complex and small G proteins. Critically important are also non-proteinaceous molecules comprising protons, calcium ions, reactive oxygen species (ROS), and signalling lipids. Among the latter, phosphatidylinositol 4,5-bisphosphate and the kinases involved in its formation have been assigned important functions. The negatively charged headgroup of this lipid serves as an interaction point at the apical plasma membrane for partners such as the exocyst complex, thereby polarising the cell and its secretion processes. Another important signalling lipid is phosphatidic acid (PA), that can either be formed by the combination of phospholipases C and diacylglycerol kinases or by phospholipases D. It further fine-tunes pollen tube growth, for example by regulating ROS formation. How the individual signalling cues are intertwined or how external guidance cues are integrated to facilitate directional growth remain open questions.
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Affiliation(s)
- Patricia Scholz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig Weg 11, D-37077 Goettingen, Germany; (J.A.); (H.E.K.)
| | | | | | - Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig Weg 11, D-37077 Goettingen, Germany; (J.A.); (H.E.K.)
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15
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Adhikari PB, Liu X, Wu X, Zhu S, Kasahara RD. Fertilization in flowering plants: an odyssey of sperm cell delivery. PLANT MOLECULAR BIOLOGY 2020; 103:9-32. [PMID: 32124177 DOI: 10.1007/s11103-020-00987-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 02/26/2020] [Indexed: 05/22/2023]
Abstract
In light of the available discoveries in the field, this review manuscript discusses on plant reproduction mechanism and molecular players involved in the process. Sperm cells in angiosperms are immotile and are physically distant to the female gametophytes (FG). To secure the production of the next generation, plants have devised a clever approach by which the two sperm cells in each pollen are safely delivered to the female gametophyte where two fertilization events occur (by each sperm cell fertilizing an egg cell and central cell) to give rise to embryo and endosperm. Each of the successfully fertilized ovules later develops into a seed. Sets of macromolecules play roles in pollen tube (PT) guidance, from the stigma, through the transmitting tract and funiculus to the micropylar end of the ovule. Other sets of genetic players are involved in PT reception and in its rupture after it enters the ovule, and yet other sets of genes function in gametic fusion. Angiosperms have come long way from primitive reproductive structure development to today's sophisticated, diverse, and in most cases flamboyant organ. In this review, we will be discussing on the intricate yet complex molecular mechanism of double fertilization and how it might have been shaped by the evolutionary forces focusing particularly on the model plant Arabidopsis.
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Affiliation(s)
- Prakash B Adhikari
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Xiaoyan Liu
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Xiaoyan Wu
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Shaowei Zhu
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Ryushiro D Kasahara
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
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16
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Vigani G, Costa A. Harnessing the new emerging imaging technologies to uncover the role of Ca 2+ signalling in plant nutrient homeostasis. PLANT, CELL & ENVIRONMENT 2019; 42:2885-2901. [PMID: 31286524 DOI: 10.1111/pce.13611] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/03/2019] [Accepted: 07/05/2019] [Indexed: 05/26/2023]
Abstract
Increasing crop yields by using ecofriendly practices is of high priority to tackle problems regarding food security and malnutrition worldwide. A sustainable crop production requires a limited use of fertilizer and the employment of plant varieties with improved ability to acquire nutrients from soil. To reach these goals, the scientific community aims to understand plant nutrients homeostasis by deciphering the nutrient sensing and signalling mechanisms of plants. Several lines of evidence about the involvement of Ca2+ as the signal of an impaired nutrient availability have been reported. Ca2+ signalling is a tightly regulated process that requires specific protein toolkits to perceive external stimuli and to induce the specific responses in the plant needed to survive. Here, we summarize both older and recent findings concerning the involvement of Ca2+ signalling in the homeostasis of nutrients. In this review, we present new emerging technologies, based on the use of genetically encoded Ca2+ sensors and advanced microscopy, which offer the chance to perform in planta analyses of Ca2+ dynamics at cellular resolution. The harnessing of these technologies with different genetic backgrounds and subjected to different nutritional stresses will provide important insights to the still little-known mechanisms of nutrient sensing in plants.
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Affiliation(s)
- Gianpiero Vigani
- Department of Life Sciences and Systems Biology, University of Turin, Turin, 10135, Italy
| | - Alex Costa
- Department of Biosciences, University of Milan, Milan, 20133, Italy
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17
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Scheible N, McCubbin A. Signaling in Pollen Tube Growth: Beyond the Tip of the Polarity Iceberg. PLANTS (BASEL, SWITZERLAND) 2019; 8:E156. [PMID: 31181594 PMCID: PMC6630365 DOI: 10.3390/plants8060156] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/04/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022]
Abstract
The coordinated growth of pollen tubes through floral tissues to deliver the sperm cells to the egg and facilitate fertilization is a highly regulated process critical to the Angiosperm life cycle. Studies suggest that the concerted action of a variety of signaling pathways underlies the rapid polarized tip growth exhibited by pollen tubes. Ca2+ and small GTPase-mediated pathways have emerged as major players in the regulation of pollen tube growth. Evidence suggests that these two signaling pathways not only integrate with one another but also with a variety of other important signaling events. As we continue to elucidate the mechanisms involved in pollen tube growth, there is a growing importance in taking a holistic approach to studying these pathways in order to truly understand how tip growth in pollen tubes is orchestrated and maintained. This review considers our current state of knowledge of Ca2+-mediated and GTPase signaling pathways in pollen tubes, how they may intersect with one another, and other signaling pathways involved. There will be a particular focus on recent reports that have extended our understanding in these areas.
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Affiliation(s)
- Nolan Scheible
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA.
| | - Andrew McCubbin
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA.
- Center for Reproductive Biology, Pullman, WA, 99164, USA.
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18
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Parrotta L, Faleri C, Guerriero G, Cai G. Cold stress affects cell wall deposition and growth pattern in tobacco pollen tubes. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 283:329-342. [PMID: 31128704 DOI: 10.1016/j.plantsci.2019.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/29/2019] [Accepted: 03/15/2019] [Indexed: 05/08/2023]
Abstract
Cold is an abiotic stress seriously threatening crop productivity by decreasing biomass production. The pollen tube is a target of cold stress, but also a useful model to address questions on cell wall biosynthesis. We here provide (immuno)cytological data relative to the impact of cold on the pollen tube cell wall. We clearly show that the growth pattern is severely affected by the stress, since the typical pulsed-growth mechanism accompanied by the periodic deposition of pectin rings is absent/severely reduced. Additionally, pectins and cellulose accumulate in bulges provoked by the stress, while callose, which colocalizes with pectins in the periodic rings formed during pulsed growth, accumulates randomly in the stressed samples. The altered distribution of the cell wall components is accompanied by differences in the localization of glucan synthases: cellulose synthase shows a more diffuse localization, while callose synthase shows a more frequent cytoplasmic accumulation, thereby denoting a failure in plasma membrane insertion. The cell wall observations are complemented by the analysis of intracellular Ca2+, pH and reactive oxygen species (ROS): while in the case of pH no major differences are observed, a less focused Ca2+ and ROS gradients are present in the stressed samples. The standard oscillatory growth of pollen tubes is recovered by transient changes of turgor pressure induced by hypoosmotic media. Overall our data contribute to the understanding of the impact that cold stress has on the normal development of the pollen tube and unveil the cell wall-related aberrant features accompanying the observed alterations.
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Affiliation(s)
- Luigi Parrotta
- Università di Bologna, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Via Irnerio 42, Bologna, Italy
| | - Claudia Faleri
- Università di Siena, Dipartimento di Scienze della Vita, via P.A. Mattioli 4, Siena, Italy
| | - Gea Guerriero
- Research and Innovation Department, Luxembourg Institute of Science and Technology, 5 avenue des Hauts-Fourneaux, L-4362, Esch/Alzette, Luxembourg
| | - Giampiero Cai
- Università di Siena, Dipartimento di Scienze della Vita, via P.A. Mattioli 4, Siena, Italy.
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19
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Laggoun F, Dardelle F, Dehors J, Falconet D, Driouich A, Rochais C, Dallemagne P, Lehner A, Mollet JC. A chemical screen identifies two novel small compounds that alter Arabidopsis thaliana pollen tube growth. BMC PLANT BIOLOGY 2019; 19:152. [PMID: 31010418 PMCID: PMC6475968 DOI: 10.1186/s12870-019-1743-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 03/27/2019] [Indexed: 05/23/2023]
Abstract
BACKGROUND During sexual reproduction, pollen grains land on the stigma, rehydrate and produce pollen tubes that grow through the female transmitting-tract tissue allowing the delivery of the two sperm cells to the ovule and the production of healthy seeds. Because pollen tubes are single cells that expand by tip-polarized growth, they represent a good model to study the growth dynamics, cell wall deposition and intracellular machineries. Aiming to understand this complex machinery, we used a low throughput chemical screen approach in order to isolate new tip-growth disruptors. The effect of a chemical inhibitor of monogalactosyldiacylglycerol synthases, galvestine-1, was also investigated. The present work further characterizes their effects on the tip-growth and intracellular dynamics of pollen tubes. RESULTS Two small compounds among 258 were isolated based on their abilities to perturb pollen tube growth. They were found to disrupt in vitro pollen tube growth of tobacco, tomato and Arabidopsis thaliana. We show that these 3 compounds induced abnormal phenotypes (bulging and/or enlarged pollen tubes) and reduced pollen tube length in a dose dependent manner. Pollen germination was significantly reduced after treatment with the two compounds isolated from the screen. They also affected cell wall material deposition in pollen tubes. The compounds decreased anion superoxide accumulation, disorganized actin filaments and RIC4 dynamics suggesting that they may affect vesicular trafficking at the pollen tube tip. CONCLUSION These molecules may alter directly or indirectly ROP1 activity, a key regulator of pollen tube growth and vesicular trafficking and therefore represent good tools to further study cellular dynamics during polarized-cell growth.
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Affiliation(s)
- Ferdousse Laggoun
- Normandie Université, UNIROUEN, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale EA4358, Fédération de Recherche “NORVEGE”- FED 4277, 76000 Rouen, France
| | - Flavien Dardelle
- Normandie Université, UNIROUEN, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale EA4358, Fédération de Recherche “NORVEGE”- FED 4277, 76000 Rouen, France
- Present Address: LPS-BioSciences, Bâtiment 409, Université Paris-Sud, 91400 Orsay, France
| | - Jérémy Dehors
- Normandie Université, UNIROUEN, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale EA4358, Fédération de Recherche “NORVEGE”- FED 4277, 76000 Rouen, France
| | - Denis Falconet
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, CEA, INRA, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, CEA Grenoble, 38000 Grenoble, cedex 9 France
| | - Azeddine Driouich
- Normandie Université, UNIROUEN, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale EA4358, Fédération de Recherche “NORVEGE”- FED 4277, 76000 Rouen, France
| | - Christophe Rochais
- Normandie Université, UNICAEN, Centre d’Etudes et de Recherche sur le Médicament de Normandie, CNRS 3038 INC3M, SFR ICORE, 14032, Caen, France
| | - Patrick Dallemagne
- Normandie Université, UNICAEN, Centre d’Etudes et de Recherche sur le Médicament de Normandie, CNRS 3038 INC3M, SFR ICORE, 14032, Caen, France
| | - Arnaud Lehner
- Normandie Université, UNIROUEN, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale EA4358, Fédération de Recherche “NORVEGE”- FED 4277, 76000 Rouen, France
| | - Jean-Claude Mollet
- Normandie Université, UNIROUEN, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale EA4358, Fédération de Recherche “NORVEGE”- FED 4277, 76000 Rouen, France
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20
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Determination of Phototropism and Polarotropism in Fern Protonemal Cells. Methods Mol Biol 2019. [PMID: 30694464 DOI: 10.1007/978-1-4939-9015-3_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Fern protonemal cells grow at their apices as long, undivided filamentous cells toward red (or weak white) light and change their growth direction if the light direction is changed (i.e., phototropism). When protonemata growing between an agar surface and cover glass are irradiated with polarized red light through the glass on the protonemal side, they start growing at the point where the direction of the vibration plane of polarized light and the transition moment of the photoreceptor, which is parallel to the plasma membrane of the cell's apical part, are equal (i.e., polarotropism). Herein, the methods on how to induce and observe this protonemal phototropism and polarotropism are described.
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21
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Zheng RH, Su SD, Xiao H, Tian HQ. Calcium: A Critical Factor in Pollen Germination and Tube Elongation. Int J Mol Sci 2019; 20:E420. [PMID: 30669423 PMCID: PMC6358865 DOI: 10.3390/ijms20020420] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 12/20/2018] [Accepted: 12/25/2018] [Indexed: 02/07/2023] Open
Abstract
Pollen is the male gametophyte of higher plants. Its major function is to deliver sperm cells to the ovule to ensure successful fertilization. During this process, many interactions occur among pollen tubes and pistil cells and tissues, and calcium ion (Ca2+) dynamics mediate these interactions among cells to ensure that pollen reaches the embryo sac. Although the precise functions of Ca2+ dynamics in the cells are unknown, we can speculate about its roles on the basis of its spatial and temporal characteristics during these interactions. The results of many studies indicate that calcium is a critical element that is strongly related to pollen germination and pollen tube growth.
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Affiliation(s)
- Ren Hua Zheng
- The Key Laboratory of Timber Forest Breeding and Cultivation for Mountainous Areas in Southern China, Fujian Academy of Forestry, Fuzhou 350012, China.
| | - Shun De Su
- The Key Laboratory of Timber Forest Breeding and Cultivation for Mountainous Areas in Southern China, Fujian Academy of Forestry, Fuzhou 350012, China.
| | - Hui Xiao
- The Key Laboratory of Timber Forest Breeding and Cultivation for Mountainous Areas in Southern China, Fujian Academy of Forestry, Fuzhou 350012, China.
| | - Hui Qiao Tian
- School of Life Sciences, Xiamen University, Xiamen 361102, China.
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22
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Wu Y, Qin B, Feng K, Yan R, Kang E, Liu T, Shang Z. Extracellular ATP promoted pollen germination and tube growth of Nicotiana tabacum through promoting K + and Ca 2+ absorption. PLANT REPRODUCTION 2018; 31:399-410. [PMID: 29934740 DOI: 10.1007/s00497-018-0341-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 06/15/2018] [Indexed: 05/15/2023]
Abstract
Extracellular ATP (eATP) plays an essential role in plant growth, development, and stress tolerance. Here, we report that eATP participated in Nicotiana tabacum pollen germination (PG) and pollen tube growth (PTG) by regulating K+ and Ca2+ influx. Exogenous ATP or ADP effectively promoted PG and PTG in a dose-dependent manner; weakly hydrolysable ATP analog (ATPγS) showed a similar effect. AMP, adenosine, adenine, and phosphate did not affect PG or PTG. Within a certain range, higher concentrations of K+ or Ca2+ in the medium increased the effect of ATP in promoting PG and PTG. However, in mediums containing K+ or Ca2+ concentrations above this range, the effect of ATP was reversed, resulting in PG and PTG inhibition. Ca2+ chelators (EGTA), Ca2+ channel blockers, and K+ channel blockers suppressed ATP-promoted PG and PTG. Results from a patch clamp showed that ATP activated a K+ and Ca2+ influx in pollen protoplasts. These results suggest that, as an apoplastic signal, eATP may be involved in PG and PTG via regulating Ca2+ and K+ absorption.
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Affiliation(s)
- Yansheng Wu
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
- Department of Chemistry Engineering and Biological Technology, Xingtai University, Xingtai, 054001, Hebei, China
| | - Baozhi Qin
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Kaili Feng
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Ruolin Yan
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Erfang Kang
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Ting Liu
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Zhonglin Shang
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China.
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23
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Wu HC, Bulgakov VP, Jinn TL. Pectin Methylesterases: Cell Wall Remodeling Proteins Are Required for Plant Response to Heat Stress. FRONTIERS IN PLANT SCIENCE 2018; 9:1612. [PMID: 30459794 PMCID: PMC6232315 DOI: 10.3389/fpls.2018.01612] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 10/17/2018] [Indexed: 05/21/2023]
Abstract
Heat stress (HS) is expected to be of increasing worldwide concern in the near future, especially with regard to crop yield and quality as a consequence of rising or varying temperatures as a result of global climate change. HS response (HSR) is a highly conserved mechanism among different organisms but shows remarkable complexity and unique features in plants. The transcriptional regulation of HSR is controlled by HS transcription factors (HSFs) which allow the activation of HS-responsive genes, among which HS proteins (HSPs) are best characterized. Cell wall remodeling constitutes an important component of plant responses to HS to maintain overall function and growth; however, little is known about the connection between cell wall remodeling and HSR. Pectin controls cell wall porosity and has been shown to exhibit structural variation during plant growth and in response to HS. Pectin methylesterases (PMEs) are present in multigene families and encode isoforms with different action patterns by removal of methyl esters to influencing the properties of cell wall. We aimed to elucidate how plant cell walls respond to certain environmental cues through cell wall-modifying proteins in connection with modifications in cell wall machinery. An overview of recent findings shed light on PMEs contribute to a change in cell-wall composition/structure. The fine-scale modulation of apoplastic calcium ions (Ca2+) content could be mediated by PMEs in response to abiotic stress for both the assembly and disassembly of the pectic network. In particular, this modulation is prevalent in guard cell walls for regulating cell wall plasticity as well as stromal aperture size, which comprise critical determinants of plant adaptation to HS. These insights provide a foundation for further research to reveal details of the cell wall machinery and stress-responsive factors to provide targets and strategies to facilitate plant adaptation.
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Affiliation(s)
- Hui-Chen Wu
- Department of Biological Sciences and Technology, National University of Tainan, Tainan, Taiwan
| | - Victor P. Bulgakov
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, Vladivostok, Russia
| | - Tsung-Luo Jinn
- Department of Life Science, Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
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24
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Diao M, Qu X, Huang S. Calcium imaging in Arabidopsis pollen cells using G-CaMP5. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:897-906. [PMID: 29424471 DOI: 10.1111/jipb.12642] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 02/07/2018] [Indexed: 05/18/2023]
Abstract
Calcium (Ca2+ ) signaling has been implicated in pollen germination and pollen tube growth. To date, however, we still know very little about how exactly Ca2+ signaling links to various physiological subcellular processes during pollen germination and pollen tube growth. Given that Ca2+ signaling is tightly related to the cytosolic concentration and dynamics of Ca2+ , it is vital to trace the dynamic changes in Ca2+ levels in order to decode Ca2+ signaling. Here, we demonstrate that G-CaMP5 serves well as an indicator for monitoring cytosolic Ca2+ dynamics in pollen cells. Using this probe, we show that cytosolic Ca2+ changes dramatically during pollen germination, and, as reported previously, Ca2+ forms a tip-focused gradient in the pollen tube and undergoes oscillation in the tip region during pollen tube growth. In particular, using G-CaMP5 allowed us to capture the dynamic changes in the cytosolic Ca2+ concentration ([Ca2+ ]cyt ) in pollen tubes in response to various exogenous treatments. Our data suggest that G-CaMP5 is a suitable probe for monitoring the dynamics of [Ca2+ ]cyt in pollen cells.
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Affiliation(s)
- Min Diao
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
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25
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Hemelryck MV, Bernal R, Ispolatov Y, Dumais J. Lily Pollen Tubes Pulse According to a Simple Spatial Oscillator. Sci Rep 2018; 8:12135. [PMID: 30108317 PMCID: PMC6092427 DOI: 10.1038/s41598-018-30635-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/07/2018] [Indexed: 11/23/2022] Open
Abstract
Polar growth is a fundamental mode of cell morphogenesis observed in nearly all major groups of organisms. Among polarly growing cells, the angiosperm pollen tubes have emerged as powerful experimental systems in large part because of their oscillatory growth, which provides a window into the network of interactions regulating morphogenesis. Empirical studies of oscillatory pollen tubes have sought to uncover the temporal sequence of cellular and molecular events that constitutes an oscillatory cycle. Here we show that in lily pollen tubes the distance or wavelength (λ = 6.3 ± 1.7 μm) over which an oscillatory cycle unfolds is more robust than the period of oscillation (τ = 39.1 ± 17.6 s) (n = 159 cells). Moreover, the oscillatory cycle is divided into slow and fast phases, with each phase unfolding over precisely one half of the wavelength. Using these observations, we show that a simple spatial bi-oscillator predicts the most common modes of oscillation observed in pollen tubes. These results call into question the traditional view of pollen tube morphogenesis as a temporal succession of cellular events. Space, not time, may be the most natural metric to inteprete the morphogenetic dynamics of these cells.
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Affiliation(s)
| | - Roberto Bernal
- Departamento de Física, Universidad de Santiago de Chile, Santiago, 9170124, Chile
| | - Yaroslav Ispolatov
- Departamento de Física, Universidad de Santiago de Chile, Santiago, 9170124, Chile
| | - Jacques Dumais
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Viña del Mar, Region V, Chile.
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26
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Transcriptome Analysis Provides Insight into the Molecular Mechanisms Underlying gametophyte factor 2-Mediated Cross-Incompatibility in Maize. Int J Mol Sci 2018; 19:ijms19061757. [PMID: 29899298 PMCID: PMC6032218 DOI: 10.3390/ijms19061757] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/12/2018] [Accepted: 05/28/2018] [Indexed: 12/26/2022] Open
Abstract
In maize (Zea mays L.), unilateral cross-incompatibility (UCI) is controlled by Gametophyte factors (Ga), including Ga1, Ga2, and Tcb1; however, the molecular mechanisms underpinning this process remain unexplored. Here, we report the pollination phenotype of an inbred line, 511L, which carries a near-dominant Ga2-S allele. We performed a high-throughput RNA sequencing (RNA-Seq) analysis of the compatible and incompatible crosses between 511L and B73, to identify the transcriptomic differences associated with Ga2-mediated UCI. An in vivo kinetics analysis revealed that the growth of non-self pollen tubes was blocked at the early stages after pollination in 511L, maintaining the UCI barrier in Ga2. In total, 25,759 genes were expressed, of which, 2063 differentially expressed genes (DEGs) were induced by pollination (G_GG, G_GB, B_BB, B_BG). A gene ontology (GO) enrichment analysis revealed that these genes were specifically enriched in functions involved in cell wall strength and pectic product modification. Moreover, 1839, 4382, and 5041 genes were detected to differentially express under same pollination treatments, including B_G, BG_GG, and BB_GB, respectively. A total of 1467 DEGs were constitutively expressed between the two inbred lines following pollination treatments, which were enriched in metabolic processes, flavonoid biosynthesis, cysteine biosynthesis, and vacuole functions. Furthermore, we confirmed 14 DEGs related to cell wall modification and stress by qRT-PCR, which might be involved in Ga2-S-mediated UCI. Our results provide a comprehensive foundation for the molecular mechanisms involved in silks of UCI mediated by Ga2-S.
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27
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Barberini ML, Sigaut L, Huang W, Mangano S, Juarez SPD, Marzol E, Estevez J, Obertello M, Pietrasanta L, Tang W, Muschietti J. Calcium dynamics in tomato pollen tubes using the Yellow Cameleon 3.6 sensor. PLANT REPRODUCTION 2018; 31:159-169. [PMID: 29236154 DOI: 10.1007/s00497-017-0317-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 12/04/2017] [Indexed: 06/07/2023]
Abstract
In vitro tomato pollen tubes show a cytoplasmic calcium gradient that oscillates with the same period as growth. Pollen tube growth requires coordination between the tip-focused cytoplasmic calcium concentration ([Ca2+]cyt) gradient and the actin cytoskeleton. This [Ca2+]cyt gradient is necessary for exocytosis of small vesicles, which contributes to the delivery of new membrane and cell wall at the pollen tube tip. The mechanisms that generate and maintain this [Ca2+]cyt gradient are not completely understood. Here, we studied calcium dynamics in tomato (Solanum lycopersicum) pollen tubes using transgenic tomato plants expressing the Yellow Cameleon 3.6 gene under the pollen-specific promoter LAT52. We use tomato as an experimental model because tomato is a Solanaceous plant that is easy to transform, and has an excellent genomic database and genetic stock center, and unlike Arabidopsis, tomato pollen is a good system to do biochemistry. We found that tomato pollen tubes showed an oscillating tip-focused [Ca2+]cyt gradient with the same period as growth. Then, we used a pharmacological approach to disturb the intracellular Ca2+ homeostasis, evaluating how the [Ca2+]cyt gradient, pollen germination and in vitro pollen tube growth were affected. We found that cyclopiazonic acid (CPA), a drug that inhibits plant PIIA-type Ca2+-ATPases, increased [Ca2+]cyt in the subapical zone, leading to the disappearance of the Ca2+ oscillations and inhibition of pollen tube growth. In contrast, 2-aminoethoxydiphenyl borate (2-APB), an inhibitor of Ca2+ released from the endoplasmic reticulum to the cytoplasm in animals cells, completely reduced [Ca2+]cyt at the tip of the tube, blocked the gradient and arrested pollen tube growth. Although both drugs have antagonistic effects on [Ca2+]cyt, both inhibited pollen tube growth triggering the disappearance of the [Ca2+]cyt gradient. When CPA and 2-APB were combined, their individual inhibitory effects on pollen tube growth were partially compensated. Finally, we found that GsMTx-4, a peptide from spider venom that blocks stretch-activated Ca2+ channels, inhibited tomato pollen germination and had a heterogeneous effect on pollen tube growth, suggesting that these channels are also involved in the maintenance of the [Ca2+]cyt gradient. All these results indicate that tomato pollen tube is an excellent model to study calcium dynamics.
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Affiliation(s)
- María Laura Barberini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, "Dr. Héctor Torres" (INGEBI-CONICET), Vuelta de Obligado 2490, C1428ADN, Buenos Aires, Argentina
| | - Lorena Sigaut
- Instituto de Física de Buenos Aires (IFIBA-CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón I, C1428EHA, Buenos Aires, Argentina
| | - Weijie Huang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Silvina Mangano
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, CP C1405BWE, Buenos Aires, Argentina
| | - Silvina Paola Denita Juarez
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, CP C1405BWE, Buenos Aires, Argentina
| | - Eliana Marzol
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, CP C1405BWE, Buenos Aires, Argentina
| | - José Estevez
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, CP C1405BWE, Buenos Aires, Argentina
| | - Mariana Obertello
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, "Dr. Héctor Torres" (INGEBI-CONICET), Vuelta de Obligado 2490, C1428ADN, Buenos Aires, Argentina
| | - Lía Pietrasanta
- Instituto de Física de Buenos Aires (IFIBA-CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón I, C1428EHA, Buenos Aires, Argentina
- Centro de Microscopías Avanzadas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón I, C1428EHA, Buenos Aires, Argentina
| | - Weihua Tang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
| | - Jorge Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, "Dr. Héctor Torres" (INGEBI-CONICET), Vuelta de Obligado 2490, C1428ADN, Buenos Aires, Argentina.
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA, Buenos Aires, Argentina.
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Li J, Li Y, Deng Y, Chen P, Feng F, Chen W, Zhou X, Wang Y. A calcium-dependent protein kinase, ZmCPK32, specifically expressed in maize pollen to regulate pollen tube growth. PLoS One 2018; 13:e0195787. [PMID: 29813101 PMCID: PMC5973587 DOI: 10.1371/journal.pone.0195787] [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: 11/04/2017] [Accepted: 03/29/2018] [Indexed: 01/10/2023] Open
Abstract
Calcium-dependent protein kinases (CPKs) play an essential role in the regulation of pollen tube growth. Although CPK genes have been identified in maize, and some have been functionally characterized, the molecular function of ZmCPKs associated with pollen tube development remains less well studied. Here, we report that a pollen-specific CPK, ZmCPK32, is involved in the regulation of pollen germination and tube extension. ZmCPK32 exhibited CPK activity and was localized on the plasma membrane and punctate internal membrane compartments via N-terminal acylation. In situ hybridization and real-time PCR revealed that ZmCPK32 transcripts accumulated in pollen and expression was dramatically upregulated during shedding. To elucidate the function of this gene, we transiently expressed a ZmCPK32-GFP fusion protein in tobacco pollen using microparticle bombardment. ZmCPK32 accumulation inhibited pollen germination and reduced pollen tube growth, but this effect was abolished when the kinase-inactive variant was expressed, indicating that kinase activity is critical for its regulatory function. In addition, the plasma membrane localization of ZmCPK32 is essential for regulating polar growth, as pollen expressing the cytosol-localized kinase displayed reduced tube length but germinated well. Moreover, the constitutively active form of ZmCPK32 enhanced the reduction in the germination rate, indicating that the specific activation of ZmCPK32 via calcium ions at the cortical growth point is essential for regulating appropriate germination. The results suggest that ZmCPK32 is functionally associated with pollen tube growth, and could represent a potential target for breeding male-sterile maize.
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Affiliation(s)
- Jie Li
- Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Yihao Li
- Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Yanling Deng
- Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Ping Chen
- Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Fen Feng
- Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Wanwan Chen
- Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Xiaojin Zhou
- Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
- Department of Crop Genomic & Genetic Improvement, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail: (YDW); (XJZ)
| | - Yingdian Wang
- Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
- * E-mail: (YDW); (XJZ)
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29
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Gutermuth T, Herbell S, Lassig R, Brosché M, Romeis T, Feijó JA, Hedrich R, Konrad KR. Tip-localized Ca 2+ -permeable channels control pollen tube growth via kinase-dependent R- and S-type anion channel regulation. THE NEW PHYTOLOGIST 2018; 218:1089-1105. [PMID: 29522235 DOI: 10.1111/nph.15067] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/18/2018] [Indexed: 05/26/2023]
Abstract
Pollen tubes (PTs) are characterized by having tip-focused cytosolic calcium ion (Ca2+ ) concentration ([Ca2+ ]cyt ) gradients, which are believed to control PT growth. However, the mechanisms by which the apical [Ca2+ ]cyt orchestrates PT growth are not well understood. Here, we aimed to identify these mechanisms by combining reverse genetics, cell biology, electrophysiology, and live-cell Ca2+ and anion imaging. We triggered Ca2+ -channel activation by applying hyperpolarizing voltage pulses and observed that the evoked [Ca2+ ]cyt increases were paralleled by high anion channel activity and a decrease in the cytosolic anion concentration at the PT tip. We confirmed a functional correlation between these patterns by showing that inhibition of Ca2+ -permeable channels eliminated the [Ca2+ ]cyt increase, resulting in the abrogation of anion channel activity via Ca2+ -dependent protein kinases (CPKs). Functional characterization of CPK and anion-channel mutants revealed a CPK2/20/6-dependent activation of SLAH3 and ALMT12/13/14 anion channels. The impaired growth phenotypes of anion channel and CPK mutants support the physiological significance of a kinase- and Ca2+ -dependent pathway to control PT growth via anion channel activation. Other than unveiling this functional link, our membrane hyperpolarization method allows for unprecedented manipulation of the [Ca2+ ]cyt gradient or oscillations in the PT tips and opens an array of opportunities for channel screenings.
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Affiliation(s)
- Timo Gutermuth
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| | - Sarah Herbell
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| | - Roman Lassig
- Plant Biochemistry, Dahlem Centre of Plant Sciences, FU Berlin, Königin-Luise-Straße 12/16, 14195, Berlin, Germany
| | - Mikael Brosché
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Institute of Technology, University of Tartu, Nooruse 1, 50411, Tartu, Estonia
| | - Tina Romeis
- Plant Biochemistry, Dahlem Centre of Plant Sciences, FU Berlin, Königin-Luise-Straße 12/16, 14195, Berlin, Germany
| | - José Alberto Feijó
- Department of Cell Biology & Molecular Genetics, University of Maryland, 2136 Bioscience Research Building, College Park, MD, 20742-5815, USA
| | - Rainer Hedrich
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| | - Kai Robert Konrad
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
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30
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Simultaneous imaging and functional studies reveal a tight correlation between calcium and actin networks. Proc Natl Acad Sci U S A 2018; 115:E2869-E2878. [PMID: 29507239 DOI: 10.1073/pnas.1711037115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tip-growing cells elongate in a highly polarized manner via focused secretion of flexible cell-wall material. Calcium has been implicated as a vital factor in regulating the deposition of cell-wall material. However, deciphering the molecular and mechanistic calcium targets in vivo has remained challenging. Here, we investigated intracellular calcium dynamics in the moss Physcomitrella patens, which provides a system with an abundant source of genetically identical tip-growing cells, excellent cytology, and a large molecular genetic tool kit. To visualize calcium we used a genetically encoded cytosolic FRET probe, revealing a fluctuating tipward gradient with a complex oscillatory profile. Wavelet analysis coupled with a signal-sifting algorithm enabled the quantitative comparison of the calcium behavior in cells where growth was inhibited mechanically, pharmacologically, or genetically. We found that cells with suppressed growth have calcium oscillatory profiles with longer frequencies, suggesting that there is a feedback between the calcium gradient and growth. To investigate the mechanistic basis for this feedback we simultaneously imaged cytosolic calcium and actin, which has been shown to be essential for tip growth. We found that high cytosolic calcium promotes disassembly of a tip-focused actin spot, while low calcium promotes assembly. In support of this, abolishing the calcium gradient resulted in dramatic actin accumulation at the tip. Together these data demonstrate that tipward calcium is quantitatively linked to actin accumulation in vivo and that the moss P. patens provides a powerful system to uncover mechanistic links between calcium, actin, and growth.
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31
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Lamport DTA, Tan L, Held MA, Kieliszewski MJ. Pollen tube growth and guidance: Occam's razor sharpened on a molecular arabinogalactan glycoprotein Rosetta Stone. THE NEW PHYTOLOGIST 2018; 217:491-500. [PMID: 28990197 DOI: 10.1111/nph.14845] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Occam's Razor suggests a new model of pollen tube tip growth based on a novel Hechtian oscillator that integrates a periplasmic arabinogalactan glycoprotein-calcium (AGP-Ca2+ ) capacitor with tip-localized AGPs as the source of tip-focussed cytosolic Ca2+ oscillations: Hechtian adhesion between the plasma membrane and the cell wall of the growing tip acts as a piconewton force transducer that couples the internal stress of a rapidly growing wall to the plasma membrane. Such Hechtian transduction opens stretch-activated Ca2+ channels and activates H+ -ATPase proton pump efflux that dissociates periplasmic AGP-Ca2+ resulting in a Ca2+ influx that activates exocytosis of wall precursors. Thus, a highly simplified pectic primary cell wall regulates its own synthesis by a Hechtian growth oscillator that regulates overall tip growth. By analogy with the three cryptic inscriptions of the classical Rosetta Stone, the Hechtian Hypothesis translates classical AGP function as a Ca2+ capacitor, pollen tube guide and wall plasticizer into a simple but widely applicable model of tip growth. Even wider ramifications of the Hechtian oscillator may implicate AGPs in osmosensing or gravisensing and other tropisms, leading us yet further towards the Holy Grail of plant growth.
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Affiliation(s)
- Derek T A Lamport
- School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK
| | - Li Tan
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602-4712, USA
| | - Michael A Held
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH, 45701, USA
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32
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Candeo A, Doccula FG, Valentini G, Bassi A, Costa A. Light Sheet Fluorescence Microscopy Quantifies Calcium Oscillations in Root Hairs of Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2017; 58:1161-1172. [PMID: 28379562 PMCID: PMC6383626 DOI: 10.1093/pcp/pcx045] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Calcium oscillations play a role in the regulation of the development of tip-growing plant cells. Using optical microscopy, calcium oscillations have been observed in a few systems (e.g. pollen tubes, fungal hyphae and algal rhizoids). High-resolution, non-phototoxic and rapid imaging methods are required to study the calcium oscillation in root hairs. We show that light sheet fluorescence microscopy is optimal to image growing root hairs of Arabidopsis thaliana and to follow their oscillatory tip-focused calcium gradient. We describe a protocol for performing live imaging of root hairs in seedlings expressing the cytosol-localized ratiometric calcium indicator Yellow Cameleon 3.6. Using this protocol, we measured the calcium gradient in a large number of root hairs. We characterized their calcium oscillations and correlated them with the rate of hair growth. The method was then used to screen the effect of auxin on the properties of the growing root hairs.
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Affiliation(s)
- Alessia Candeo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Fabrizio G. Doccula
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Giovanni Celoria 26, 20133 Milano, Italy
| | - Gianluca Valentini
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Andrea Bassi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Alex Costa
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Giovanni Celoria 26, 20133 Milano, Italy
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33
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Damineli DSC, Portes MT, Feijó JA. Oscillatory signatures underlie growth regimes in Arabidopsis pollen tubes: computational methods to estimate tip location, periodicity, and synchronization in growing cells. JOURNAL OF EXPERIMENTAL BOTANY 2017. [PMID: 28369603 DOI: 10.5061/dryad.6806c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Oscillations in pollen tubes have been reported for many cellular processes, including growth, extracellular ion fluxes, and cytosolic ion concentrations. However, there is a shortage of quantitative methods to measure and characterize the different dynamic regimes observed. Herein, a suite of open-source computational methods and original algorithms were integrated into an automated analysis pipeline that we employed to characterize specific oscillatory signatures in pollen tubes of Arabidopsis thaliana (Col-0). Importantly, it enabled us to detect and quantify a Ca2+ spiking behaviour upon growth arrest and synchronized oscillations involving growth, extracellular H+ fluxes, and cytosolic Ca2+, providing the basis for novel hypotheses. Our computational approach includes a new tip detection method with subpixel resolution using linear regression, showing improved ability to detect oscillations when compared to currently available methods. We named this data analysis pipeline 'Computational Heuristics for Understanding Kymographs and aNalysis of Oscillations Relying on Regression and Improved Statistics', or CHUKNORRIS. It can integrate diverse data types (imaging, electrophysiology), extract quantitative and time-explicit estimates of oscillatory characteristics from isolated time series (period and amplitude) or pairs (phase relationships and delays), and evaluate their synchronization state. Here, its performance is tested with ratiometric and single channel kymographs, ion flux data, and growth rate analysis.
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Affiliation(s)
- Daniel S C Damineli
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - Maria Teresa Portes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - José A Feijó
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
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34
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Damineli DSC, Portes MT, Feijó JA. Oscillatory signatures underlie growth regimes in Arabidopsis pollen tubes: computational methods to estimate tip location, periodicity, and synchronization in growing cells. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3267-3281. [PMID: 28369603 PMCID: PMC5853864 DOI: 10.1093/jxb/erx032] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 01/17/2017] [Indexed: 05/18/2023]
Abstract
Oscillations in pollen tubes have been reported for many cellular processes, including growth, extracellular ion fluxes, and cytosolic ion concentrations. However, there is a shortage of quantitative methods to measure and characterize the different dynamic regimes observed. Herein, a suite of open-source computational methods and original algorithms were integrated into an automated analysis pipeline that we employed to characterize specific oscillatory signatures in pollen tubes of Arabidopsis thaliana (Col-0). Importantly, it enabled us to detect and quantify a Ca2+ spiking behaviour upon growth arrest and synchronized oscillations involving growth, extracellular H+ fluxes, and cytosolic Ca2+, providing the basis for novel hypotheses. Our computational approach includes a new tip detection method with subpixel resolution using linear regression, showing improved ability to detect oscillations when compared to currently available methods. We named this data analysis pipeline 'Computational Heuristics for Understanding Kymographs and aNalysis of Oscillations Relying on Regression and Improved Statistics', or CHUKNORRIS. It can integrate diverse data types (imaging, electrophysiology), extract quantitative and time-explicit estimates of oscillatory characteristics from isolated time series (period and amplitude) or pairs (phase relationships and delays), and evaluate their synchronization state. Here, its performance is tested with ratiometric and single channel kymographs, ion flux data, and growth rate analysis.
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Affiliation(s)
- Daniel S C Damineli
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - Maria Teresa Portes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - José A Feijó
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
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35
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Pulses of Ca 2+ coordinate actin assembly and exocytosis for stepwise cell extension. Proc Natl Acad Sci U S A 2017; 114:5701-5706. [PMID: 28507141 DOI: 10.1073/pnas.1700204114] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many eukaryotic cells grow by extending their cell periphery in pulses. The molecular mechanisms underlying this process are not yet fully understood. Here we present a comprehensive model of stepwise cell extension by using the unique tip growth system of filamentous fungi. Live-cell imaging analysis, including superresolution microscopy, revealed that the fungus Aspergillus nidulans extends the hyphal tip in an oscillatory manner. The amount of F-actin and secretory vesicles (SV) accumulating at the hyphal tip oscillated with a positive temporal correlation, whereas vesicle amounts were negatively correlated to the growth rate. The intracellular Ca2+ level also pulsed with a positive temporal correlation to the amount of F-actin and SV at the hyphal tip. Two Ca2+ channels, MidA and CchA, were needed for proper tip growth and the oscillations of actin polymerization, exocytosis, and the growth rate. The data indicate a model in which transient Ca2+ pluses cause depolymerization of F-actin at the cortex and promote SV fusion with the plasma membrane, thereby extending the cell tip. Over time, Ca2+ diffuses away and F-actin and SV accumulate again at the hyphal tip. Our data provide evidence that temporally controlled actin polymerization and exocytosis are coordinated by pulsed Ca2+ influx, resulting in stepwise cell extension.
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36
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Schoenaers S, Balcerowicz D, Costa A, Vissenberg K. The Kinase ERULUS Controls Pollen Tube Targeting and Growth in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2017; 8:1942. [PMID: 29184563 PMCID: PMC5694544 DOI: 10.3389/fpls.2017.01942] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/27/2017] [Indexed: 05/09/2023]
Abstract
In this paper, we describe the role of the receptor-like kinase ERULUS (ERU) in PT growth of Arabidopsis thaliana. In silico analysis and transcriptional reporter lines revealed that ERU is only expressed in pollen and root hairs (RHs), making it a tip growth-specific kinase. Deviations from Mendelian inheritance were observed in the offspring of self-pollinated heterozygous eru plants. We found that in vivo eru PT targeting was disturbed, providing a possible explanation for the observed decrease in eru fertilization competitiveness. Extracellular calcium perception and intracellular calcium dynamics lie at the basis of in vivo pollen tube (PT) tip growth and guidance. In vitro, ERU loss-of-function lines displayed no obvious PT phenotype, unless grown on low extracellular calcium ([Ca2+]ext) medium. When grown at 12 the normal [Ca2+]ext, eru PTs grew 37% slower relative to WT PTs. Visualization of cytoplasmic [Ca2+]cyt oscillations using the Yellow Cameleon 3.6 (YC3.6) calcium sensor showed that, unlike in WT PTs, eru apical [Ca2+]cyt oscillations occur at a lower frequency when grown at lower [Ca2+]ext, consistent with the observed reduced growth velocity. Our results show that the tip growth-specific kinase ERULUS is involved in regulating Ca2+-dependent PT growth, and most importantly, fertilization efficiency through successful PT targeting to the ovules.
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Affiliation(s)
- Sébastjen Schoenaers
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
| | - Daria Balcerowicz
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
| | - Alex Costa
- Department of Biosciences, University of Milan, Milan, Italy
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Milan, Italy
| | - Kris Vissenberg
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
- Plant Biochemistry and Biotechnology Lab, Technological Educational Institute of Crete: University of Applied Sciences, Crete, Greece
- *Correspondence: Kris Vissenberg,
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37
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Winship LJ, Rounds C, Hepler PK. Perturbation Analysis of Calcium, Alkalinity and Secretion during Growth of Lily Pollen Tubes. PLANTS 2016; 6:plants6010003. [PMID: 28042810 PMCID: PMC5371762 DOI: 10.3390/plants6010003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/24/2016] [Accepted: 12/26/2016] [Indexed: 01/07/2023]
Abstract
Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily (Lilium formosanum Wallace) pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a leader, may be an activator. To gain further insight herein we reversibly inhibited growth with potassium cyanide (KCN) and followed the re-establishment of calcium, pH and secretion patterns as growth resumed. While KCN markedly slows growth and causes the associated gradients of calcium and pH to sharply decline, its removal allows growth and vital processes to fully recover. The calcium gradient reappears before growth restarts; however, it is preceded by both the alkaline band and secretion, in which the alkaline band is slightly advanced over secretion. Thus the pH gradient, rather than the tip-focused calcium gradient, may regulate pollen tube growth.
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Affiliation(s)
| | - Caleb Rounds
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| | - Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
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38
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The role of Ca 2+ and Ca 2+ channels in the gametophytic self-incompatibility of Pyrus pyrifolia. Cell Calcium 2016; 60:299-308. [DOI: 10.1016/j.ceca.2016.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 06/23/2016] [Indexed: 11/15/2022]
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39
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Hafidh S, Fíla J, Honys D. Male gametophyte development and function in angiosperms: a general concept. PLANT REPRODUCTION 2016; 29:31-51. [PMID: 26728623 DOI: 10.1007/s00497-015-0272-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 12/19/2015] [Indexed: 05/23/2023]
Abstract
Overview of pollen development. Male gametophyte development of angiosperms is a complex process that requires coordinated activity of different cell types and tissues of both gametophytic and sporophytic origin and the appropriate specific gene expression. Pollen ontogeny is also an excellent model for the dissection of cellular networks that control cell growth, polarity, cellular differentiation and cell signaling. This article describes two sequential phases of angiosperm pollen ontogenesis-developmental phase leading to the formation of mature pollen grains, and a functional or progamic phase, beginning with the impact of the grains on the stigma surface and ending at double fertilization. Here we present an overview of important cellular processes in pollen development and explosive pollen tube growth stressing the importance of reserves accumulation and mobilization and also the mutual activation of pollen tube and pistil tissues, pollen tube guidance and the communication between male and female gametophytes. We further describe the recent advances in regulatory mechanisms involved such as posttranscriptional regulation (including mass transcript storage) and posttranslational modifications to modulate protein function, intracellular metabolic signaling, ionic gradients such as Ca(2+) and H(+) ions, cell wall synthesis, protein secretion and intercellular signaling within the reproductive tissues.
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Affiliation(s)
- Said Hafidh
- Institute of Experimental Botany ASCR, v.v.i., Rozvojová 263, 165 00, Prague 6, Czech Republic
| | - Jan Fíla
- Institute of Experimental Botany ASCR, v.v.i., Rozvojová 263, 165 00, Prague 6, Czech Republic
| | - David Honys
- Institute of Experimental Botany ASCR, v.v.i., Rozvojová 263, 165 00, Prague 6, Czech Republic.
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Viničná 5, 128 44, Prague 2, Czech Republic.
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40
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Bergs A, Ishitsuka Y, Evangelinos M, Nienhaus GU, Takeshita N. Dynamics of Actin Cables in Polarized Growth of the Filamentous Fungus Aspergillus nidulans. Front Microbiol 2016; 7:682. [PMID: 27242709 PMCID: PMC4860496 DOI: 10.3389/fmicb.2016.00682] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/26/2016] [Indexed: 12/20/2022] Open
Abstract
Highly polarized growth of filamentous fungi requires a continuous supply of proteins and lipids to the hyphal tip. This transport is managed by vesicle trafficking via the actin and microtubule cytoskeletons and their associated motor proteins. Particularly, actin cables originating from the hyphal tip are essential for hyphal growth. Although, specific marker proteins have been developed to visualize actin cables in filamentous fungi, the exact organization and dynamics of actin cables has remained elusive. Here, we observed actin cables using tropomyosin (TpmA) and Lifeact fused to fluorescent proteins in living Aspergillus nidulans hyphae and studied the dynamics and regulation. GFP tagged TpmA visualized dynamic actin cables formed from the hyphal tip with cycles of elongation and shrinkage. The elongation and shrinkage rates of actin cables were similar and approximately 0.6 μm/s. Comparison of actin markers revealed that high concentrations of Lifeact reduced actin dynamics. Simultaneous visualization of actin cables and microtubules suggests temporally and spatially coordinated polymerization and depolymerization between the two cytoskeletons. Our results provide new insights into the molecular mechanism of ordered polarized growth regulated by actin cables and microtubules.
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Affiliation(s)
- Anna Bergs
- Department of Microbiology, Institute for Applied Bioscience, Karlsruhe Institute of Technology Karlsruhe, Germany
| | - Yuji Ishitsuka
- Institute of Applied Physics, Karlsruhe Institute of Technology Karlsruhe, Germany
| | - Minoas Evangelinos
- Department of Microbiology, Institute for Applied Bioscience, Karlsruhe Institute of TechnologyKarlsruhe, Germany; Faculty of Biology, University of AthensAthens, Greece
| | - G U Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of TechnologyKarlsruhe, Germany; Institute of Toxicology and Genetics, Karlsruhe Institute of TechnologyEggenstein-Leopoldshafen, Germany; Institute of Nanotechnology, Karlsruhe Institute of TechnologyEggenstein-Leopoldshafen, Germany; Department of Physics, University of Illinois at Urbana-ChampaignUrbana-Champaign, IL, USA
| | - Norio Takeshita
- Department of Microbiology, Institute for Applied Bioscience, Karlsruhe Institute of TechnologyKarlsruhe, Germany; Faculty of Life and Environmental Sciences, University of TsukubaTsukuba, Japan
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Abstract
Filamentous fungi are extremely polarized organisms, exhibiting continuous growth at their hyphal tips. The hyphal form is related to their pathogenicity in animals and plants, and their high secretion ability for biotechnology. Polarized growth requires a sequential supply of proteins and lipids to the hyphal tip. This transport is managed by vesicle trafficking via the actin and microtubule cytoskeleton. Therefore, the arrangement of the cytoskeleton is a crucial step to establish and maintain the cell polarity. This review summarizes recent findings unraveling the mechanism of polarized growth with special emphasis on the role of actin and microtubule cytoskeleton and polarity marker proteins. Rapid insertions of membranes via highly active exocytosis at hyphal tips could quickly dilute the accumulated polarity marker proteins. Recent findings by a super-resolution microscopy indicate that filamentous fungal cells maintain their polarity at the tips by repeating transient assembly and disassembly of polarity sites.
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Affiliation(s)
- Norio Takeshita
- a Department of Microbiology , Institute for Applied Bioscience, Karlsruhe Institute of Technology (KIT) , Karlsruhe , Germany.,b Faculty of Life and Environmental Sciences , University of Tsukuba , Tsukuba , Japan
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Williams JH, Edwards JA, Ramsey AJ. Economy, efficiency, and the evolution of pollen tube growth rates. AMERICAN JOURNAL OF BOTANY 2016; 103:471-483. [PMID: 26936897 DOI: 10.3732/ajb.1500264] [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: 06/04/2015] [Accepted: 10/08/2015] [Indexed: 06/05/2023]
Abstract
PREMISE Pollen tube growth rate (PTGR) is an important aspect of male gametophyte performance because of its central role in the fertilization process. Theory suggests that under intense competition, PTGRs should evolve to be faster, especially if PTGR accurately reflects gametophyte quality. Oddly, we know remarkably little about how effectively the work of tube construction is translated to elongation (growth and growth rate). Here we test the prediction that pollen tubes grow equally efficiently by comparing the scaling of wall production rate (WPR) to PTGR in three water lilies that flower concurrently: Nymphaea odorata, Nuphar advena and Brasenia schreberi. METHODS Single-donor pollinations on flower or carpel pairs were fixed just after pollen germination (time A) and 45 min later (time B). Mean PTGR was calculated as the average increase in tube length over that growth period. Tube circumferences (C) and wall thicknesses (W) were measured at time B. For each donor, WPR = mean (C × W) × mean PTGR. KEY RESULTS Within species, pollen tubes maintained a constant WPR to PTGR ratio, but species had significantly different ratios. N. odorata and N. advena had similar PTGRs, but for any given PTGR, they had the lowest and highest WPRs, respectively. CONCLUSIONS We showed that growth rate efficiencies evolved by changes in the volume of wall material used for growth and in how that material was partitioned between lateral and length dimensions. The economics of pollen tube growth are determined by tube design, which is consequent on trade-offs between efficient growth and other pollen tube functions.
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Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA
| | - Jacob A Edwards
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA
| | - Adam J Ramsey
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA
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Cyclic nucleotide-gated channel 18 is an essential Ca2+ channel in pollen tube tips for pollen tube guidance to ovules in Arabidopsis. Proc Natl Acad Sci U S A 2016; 113:3096-101. [PMID: 26929345 DOI: 10.1073/pnas.1524629113] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In flowering plants, pollen tubes are guided into ovules by multiple attractants from female gametophytes to release paired sperm cells for double fertilization. It has been well-established that Ca(2+) gradients in the pollen tube tips are essential for pollen tube guidance and that plasma membrane Ca(2+) channels in pollen tube tips are core components that regulate Ca(2+) gradients by mediating and regulating external Ca(2+) influx. Therefore, Ca(2+) channels are the core components for pollen tube guidance. However, there is still no genetic evidence for the identification of the putative Ca(2+) channels essential for pollen tube guidance. Here, we report that the point mutations R491Q or R578K in cyclic nucleotide-gated channel 18 (CNGC18) resulted in abnormal Ca(2+) gradients and strong pollen tube guidance defects by impairing the activation of CNGC18 in Arabidopsis. The pollen tube guidance defects of cngc18-17 (R491Q) and of the transfer DNA (T-DNA) insertion mutant cngc18-1 (+/-) were completely rescued by CNGC18. Furthermore, domain-swapping experiments showed that CNGC18's transmembrane domains are indispensable for pollen tube guidance. Additionally, we found that, among eight Ca(2+) channels (including six CNGCs and two glutamate receptor-like channels), CNGC18 was the only one essential for pollen tube guidance. Thus, CNGC18 is the long-sought essential Ca(2+) channel for pollen tube guidance in Arabidopsis.
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Kang HK, Nam KH. Reverse function of ROS-induced CBL10 during salt and drought stress responses. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 243:49-55. [PMID: 26795150 DOI: 10.1016/j.plantsci.2015.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 11/14/2015] [Accepted: 11/21/2015] [Indexed: 05/27/2023]
Abstract
Cellular levels of Ca(2+) and reactive oxygen species (ROS) are maintained at low levels in the cytosol but fluctuate greatly when acting as second messengers to decode environmental and developmental signals. Phytohormones are primary signals leading to various changes in ROS or Ca(2+) signaling during synergistic and antagonistic cross-talk. In this study, we found that brassinosteroids (BRs), hormones involved in diverse plant developmental processes, promote ROS production. To identify downstream signaling components of ROS during BR-mediated plant development, we searched for genes whose expression remained unchanged by ROS only in BR- signaling mutants and found calcineurin B-like (CBL) 10, which encodes a CBL should be changed to CBL10. protein that senses calcium. ROS-induced CBL10 expression was nullified and endogenous CBL10 expression in the shoot was low in the BR-signaling mutant. Using a cbl10 mutant and a transgenic plant overexpressing CBL10, we showed that BR sensitivity during hypocotyl growth decreased in the cbl10 mutant under salt stress, providing an additional mechanism for positive regulation of salt stress by CBL10. We also demonstrated that CBL10 negatively affects tolerance to drought and is not mediated by abscisic acid-induced signaling. Our results suggest that Ca(2+) signaling through CBL10 differently affects the response to abiotic stresses, partly by regulating BR sensitivity of plant tissues.
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Affiliation(s)
- Hyun Kyung Kang
- Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Republic of Korea
| | - Kyoung Hee Nam
- Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Republic of Korea.
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45
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Cui Y, Ling Y, Zhou J, Li X. Interference of the Histone Deacetylase Inhibits Pollen Germination and Pollen Tube Growth in Picea wilsonii Mast. PLoS One 2015; 10:e0145661. [PMID: 26710276 PMCID: PMC4692408 DOI: 10.1371/journal.pone.0145661] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/07/2015] [Indexed: 12/17/2022] Open
Abstract
Histone deacetylase (HDAC) is a crucial component in the regulation of gene expression in various cellular processes in animal and plant cells. HDAC has been reported to play a role in embryogenesis. However, the effect of HDAC on androgamete development remains unclear, especially in gymnosperms. In this study, we used the HDAC inhibitors trichostatin A (TSA) and sodium butyrate (NaB) to examine the role of HDAC in Picea wilsonii pollen germination and pollen tube elongation. Measurements of the tip-focused Ca2+ gradient revealed that TSA and NaB influenced this gradient. Immunofluorescence showed that actin filaments were disrupted into disorganized fragments. As a result, the vesicle trafficking was disturbed, as determined by FM4-64 labeling. Moreover, the distribution of pectins and callose in cell walls was significantly altered in response to TSA and NaB. Our results suggest that HDAC affects pollen germination and polarized pollen tube growth in Picea wilsonii by affecting the intracellular Ca2+ concentration gradient, actin organization patterns, vesicle trafficking, as well as the deposition and configuration of cell wall components.
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Affiliation(s)
- Yaning Cui
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Yu Ling
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Junhui Zhou
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Xiaojuan Li
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
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Qian D, Nan Q, Yang Y, Li H, Zhou Y, Zhu J, Bai Q, Zhang P, An L, Xiang Y. Gelsolin-Like Domain 3 Plays Vital Roles in Regulating the Activities of the Lily Villin/Gelsolin/Fragmin Superfamily. PLoS One 2015; 10:e0143174. [PMID: 26587673 PMCID: PMC4654503 DOI: 10.1371/journal.pone.0143174] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 11/02/2015] [Indexed: 02/08/2023] Open
Abstract
The villin/gelsolin/fragmin superfamily is a major group of Ca2+-dependent actin-binding proteins (ABPs) involved in various cellular processes. Members of this superfamily typically possess three or six tandem gelsolin-like (G) domains, and each domain plays a distinct role in actin filament dynamics. Although the activities of most G domains have been characterized, the biochemical function of the G3 domain remains poorly understood. In this study, we carefully compared the detailed biochemical activities of ABP29 (a new member of this family that contains the G1-G2 domains of lily ABP135) and ABP135G1-G3 (which contains the G1-G3 domains of lily ABP135). In the presence of high Ca2+ levels in vitro (200 and 10 μM), ABP135G1-G3 exhibited greater actin severing and/or depolymerization and nucleating activities than ABP29, and these proteins had similar actin capping activities. However, in the presence of low levels of Ca2+ (41 nM), ABP135G1-G3 had a weaker capping activity than ABP29. In addition, ABP29 inhibited F-actin depolymerization, as shown by dilution-mediated depolymerization assay, differing from the typical superfamily proteins. In contrast, ABP135G1-G3 accelerated F-actin depolymerization. All of these results demonstrate that the G3 domain plays specific roles in regulating the activities of the lily villin/gelsolin/fragmin superfamily proteins.
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Affiliation(s)
- Dong Qian
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Qiong Nan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yueming Yang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Hui Li
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yuelong Zhou
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jingen Zhu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Qifeng Bai
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China
| | - Pan Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Lizhe An
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yun Xiang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
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Wang SS, Diao WZ, Yang X, Qiao Z, Wang M, Acharya BR, Zhang W. Arabidopsis thaliana CML25 mediates the Ca(2+) regulation of K(+) transmembrane trafficking during pollen germination and tube elongation. PLANT, CELL & ENVIRONMENT 2015; 38:2372-86. [PMID: 25923414 DOI: 10.1111/pce.12559] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 04/09/2015] [Indexed: 05/10/2023]
Abstract
The concentration alteration of cytosolic-free calcium ([Ca(2+) ]cyt ) is a well-known secondary messenger in plants and plays important roles during pollen grain germination and tube elongation. Here we demonstrate that CML25, a member of calmodulin-like proteins, has Ca(2+) -binding activity and plays a role in pollen grain germination, tube elongation and seed setting. CML25 transcript was abundant in mature pollen grains and pollen tubes, and its product CML25 protein was primarily directed to the cytoplasm. Two independent CML25 loss-of-function T-DNA insertion mutants suffered a major reduction in both the rate of pollen germination and the elongation of the pollen tube. Also, pollen grains of cml25 mutants were less sensitive to the external K(+) and Ca(2+) concentration than wild-type pollen. The disruption of CML25 increased the [Ca(2+) ]cyt in both the pollen grain and the pollen tube, which in turn impaired the Ca(2+) -dependent inhibition of whole-cell inward K(+) currents in protoplasts prepared from these materials (pollen grain and pollen tube). Complementation of cml25-1 mutant resulted in the recovery of wild-type phenotype. Our findings indicate that CML25 is an important transducer in the Ca(2+) -mediated regulation of K(+) influx during pollen germination and tube elongation.
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Affiliation(s)
- Shuang-Shuang Wang
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
| | - Wen-Zhu Diao
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
| | - Xue Yang
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
- College of Technological Gardening, Shandong Yingcai University, Jinan, 250104, China
| | - Zhu Qiao
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
| | - Mei Wang
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
| | - Biswa R Acharya
- Department of Biology, Pennsylvania State University University Park, State College, PA, 16802, USA
| | - Wei Zhang
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
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Ishitsuka Y, Savage N, Li Y, Bergs A, Grün N, Kohler D, Donnelly R, Nienhaus GU, Fischer R, Takeshita N. Superresolution microscopy reveals a dynamic picture of cell polarity maintenance during directional growth. SCIENCE ADVANCES 2015; 1:e1500947. [PMID: 26665168 PMCID: PMC4673053 DOI: 10.1126/sciadv.1500947] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 09/14/2015] [Indexed: 05/02/2023]
Abstract
Polar (directional) cell growth, a key cellular mechanism shared among a wide range of species, relies on targeted insertion of new material at specific locations of the plasma membrane. How these cell polarity sites are stably maintained during massive membrane insertion has remained elusive. Conventional live-cell optical microscopy fails to visualize polarity site formation in the crowded cell membrane environment because of its limited resolution. We have used advanced live-cell imaging techniques to directly observe the localization, assembly, and disassembly processes of cell polarity sites with high spatiotemporal resolution in a rapidly growing filamentous fungus, Aspergillus nidulans. We show that the membrane-associated polarity site marker TeaR is transported on microtubules along with secretory vesicles and forms a protein cluster at that point of the apical membrane where the plus end of the microtubule touches. There, a small patch of membrane is added through exocytosis, and the TeaR cluster gets quickly dispersed over the membrane. There is an incessant disassembly and reassembly of polarity sites at the growth zone, and each new polarity site locus is slightly offset from preceding ones. On the basis of our imaging results and computational modeling, we propose a transient polarity model that explains how cell polarity is stably maintained during highly active directional growth.
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Affiliation(s)
- Yuji Ishitsuka
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Natasha Savage
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Yiming Li
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Anna Bergs
- Department of Microbiology, Institute for Applied Biosciences, KIT, 76187 Karlsruhe, Germany
| | - Nathalie Grün
- Department of Microbiology, Institute for Applied Biosciences, KIT, 76187 Karlsruhe, Germany
| | - Daria Kohler
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Rebecca Donnelly
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - G. Ulrich Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
- Institute of Nanotechnology, KIT, 76344 Eggenstein-Leopoldshafen, Germany
- Institute of Toxicology and Genetics, KIT, 76344 Eggenstein-Leopoldshafen, Germany
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Corresponding author. E-mail: (G.U.N.); (R.F.); (N.T.)
| | - Reinhard Fischer
- Department of Microbiology, Institute for Applied Biosciences, KIT, 76187 Karlsruhe, Germany
- Corresponding author. E-mail: (G.U.N.); (R.F.); (N.T.)
| | - Norio Takeshita
- Department of Microbiology, Institute for Applied Biosciences, KIT, 76187 Karlsruhe, Germany
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
- Corresponding author. E-mail: (G.U.N.); (R.F.); (N.T.)
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Suwińska A, Lenartowski R, Smoliński DJ, Lenartowska M. Molecular evidence that rough endoplasmic reticulum is the site of calreticulin translation in Petunia pollen tubes growing in vitro. PLANT CELL REPORTS 2015; 34:1189-99. [PMID: 25732863 PMCID: PMC4464644 DOI: 10.1007/s00299-015-1777-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 01/23/2015] [Accepted: 02/17/2015] [Indexed: 05/20/2023]
Abstract
KEY MESSAGE In germinating pollen grains and growing pollen tubes, CRT is translated on ER membrane-bound ribosomes in the regions where its activity is required for stabilization of tip-focused Ca (2+) gradient. Pollen tube growth requires coordination of signaling, exocytosis, and actin cytoskeletal organization. Many of these processes are thought to be controlled by finely tuned regulation of cytoplasmic Ca(2+) in discrete regions of the tube cytoplasm. Most notably, a mechanism must function to maintain a steep gradient of Ca(2+) that exists at the tip of growing pollen tube. Several pieces of evidence point to calreticulin (CRT) as a key Ca(2+)-binding/-buffering protein involved in pollen germination and pollen tube growth. We previously hypothesized that in germinating pollen and growing tubes, CRT is translated on the ribosomes associated with endoplasmic reticulum (ER) in the regions where its activity might be required. In this report, we have addressed this idea by identifying the sites where CRT mRNA, CRT protein, 18S rRNA, and rough ER are localized in Petunia pollen tubes. We observed all four components in the germinal aperture of pollen grains and in subapical regions of elongating tubes. These results seem to support our idea that CRT is translated on ER membrane-bound ribosomes during pollen germination and pollen tube growth. In elongated pollen tubes, we found CRT mainly localized in the subapical zone, where ER and Golgi stacks are abundant. In eukaryotic cells, these organelles serve as mobile intracellular stores of easily releasable Ca(2+), which can be buffered by proteins such as CRT. Therefore, we postulate that subapical-localized CRT is involved in pollen tube growth by maintaining the stable tip-focused Ca(2+) gradient and thus modulating local Ca(2+) concentration within the tube cytoplasm.
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Affiliation(s)
- Anna Suwińska
- Laboratory of Developmental Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Robert Lenartowski
- Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Dariusz Jan Smoliński
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Marta Lenartowska
- Laboratory of Developmental Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
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50
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Zhou L, Lan W, Chen B, Fang W, Luan S. A calcium sensor-regulated protein kinase, CALCINEURIN B-LIKE PROTEIN-INTERACTING PROTEIN KINASE19, is required for pollen tube growth and polarity. PLANT PHYSIOLOGY 2015; 167:1351-60. [PMID: 25713341 PMCID: PMC4378171 DOI: 10.1104/pp.114.256065] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/17/2015] [Indexed: 05/17/2023]
Abstract
Calcium plays an essential role in pollen tube tip growth. However, little is known concerning the molecular basis of the signaling pathways involved. Here, we identified Arabidopsis (Arabidopsis thaliana) CALCINEURIN B-LIKE PROTEIN-INTERACTING PROTEIN KINASE19 (CIPK19) as an important element to pollen tube growth through a functional survey for CIPK family members. The CIPK19 gene was specifically expressed in pollen grains and pollen tubes, and its overexpression induced severe loss of polarity in pollen tube growth. In the CIPK19 loss-of-function mutant, tube growth and polarity were significantly impaired, as demonstrated by both in vitro and in vivo pollen tube growth assays. Genetic analysis indicated that disruption of CIPK19 resulted in a male-specific transmission defect. Furthermore, loss of polarity induced by CIPK19 overexpression was associated with elevated cytosolic Ca2+ throughout the bulging tip, whereas LaCl3, a Ca2+ influx blocker, rescued CIPK19 overexpression-induced growth inhibition. Our results suggest that CIPK19 may be involved in maintaining Ca2+ homeostasis through its potential function in the modulation of Ca2+ influx.
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Affiliation(s)
- Liming Zhou
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Wenzhi Lan
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Binqing Chen
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Wei Fang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Sheng Luan
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
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