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Lichtscheidl I, Lancelle S, Weidinger M, Adlassnig W, Koller-Peroutka M, Bauer S, Krammer S, Hepler PK. Gland cell responses to feeding in Drosera capensis, a carnivorous plant. PROTOPLASMA 2021; 258:1291-1306. [PMID: 34155556 PMCID: PMC8523503 DOI: 10.1007/s00709-021-01667-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/11/2021] [Indexed: 05/08/2023]
Abstract
Glands of Drosera absorb and transport nutrients from captured prey, but the mechanism and dynamics remain unclear. In this study, we offered animal proteins in the form of fluorescent albumin (FITC-BSA) and observed the reactions of the glands by live cell imaging and fluorescence microscopy. The ultrastructure of these highly dynamic processes was also assessed in high-pressure frozen and freeze substituted (HPF-FS) cells. HPF-FS yielded excellent preservation of the cytoplasm of all cell types, although the cytosol looked different in gland cells as compared to endodermoid and stalk cells. Especially prominent were the ER and its contacts with the plasma membrane, plasmodesmata, and other organelles as well as continuities between organelles. Also distinct were actin microfilaments in association with ER and organelles. Application of FITC-BSA to glands caused the formation of fluorescent endosomes that pinched off the plasma membrane. Endosomes fused to larger aggregates, and accumulated in the bulk cytoplasm around the nucleus. They did not fuse with the cell sap vacuole but remained for at least three days; in addition, fluorescent vesicles also proceeded through endodermoid and transfer cells to the epidermal and parenchymal cells of the tentacle stalk.
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Affiliation(s)
- Irene Lichtscheidl
- Cell Imaging and Ultrastructure Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Sue Lancelle
- Biology Department, University of Massachusetts Amherst, 221 Morrill Science Center III; 611 North Pleasant Street, Amherst, MA 01003-9297 USA
| | - Marieluise Weidinger
- Cell Imaging and Ultrastructure Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Wolfram Adlassnig
- Cell Imaging and Ultrastructure Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Marianne Koller-Peroutka
- Cell Imaging and Ultrastructure Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Sonja Bauer
- Cell Imaging and Ultrastructure Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Stefanie Krammer
- Cell Imaging and Ultrastructure Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Peter K. Hepler
- Biology Department, University of Massachusetts Amherst, 221 Morrill Science Center III; 611 North Pleasant Street, Amherst, MA 01003-9297 USA
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Liu Z, Gao J, Cui Y, Klumpe S, Xiang Y, Erdmann PS, Jiang L. Membrane imaging in the plant endomembrane system. PLANT PHYSIOLOGY 2021; 185:562-576. [PMID: 33793889 PMCID: PMC8133680 DOI: 10.1093/plphys/kiaa040] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/11/2020] [Indexed: 05/10/2023]
Abstract
Recent studies on membrane imaging in the plant endomembrane system by 2-D/3-D CLSM and TEM provide future perspectives of whole-cell ET and cryo-FIB-aided cryo-ET analysis.
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Affiliation(s)
- Zhiqi Liu
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Jiayang Gao
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Yong Cui
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Sven Klumpe
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Yun Xiang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Philipp S Erdmann
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Liwen Jiang
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, Hong Kong
- CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China
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Mai KKK, Gao P, Kang BH. Electron Microscopy Views of Dimorphic Chloroplasts in C4 Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:1020. [PMID: 32719711 PMCID: PMC7350421 DOI: 10.3389/fpls.2020.01020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 06/22/2020] [Indexed: 05/02/2023]
Abstract
C4 plants enhance photosynthesis efficiency by concentrating CO2 to the site of Rubisco action. Chloroplasts in C4 plants exhibit structural dimorphism because thylakoid architectures vary depending on energy requirements. Advances in electron microscopy imaging capacity and sample preparation technologies allowed characterization of thylakoid structures and their macromolecular arrangements with unprecedented precision mostly in C3 plants. The thylakoid is assembled during chloroplast biogenesis through collaboration between the plastid and nuclear genomes. Recently, the membrane dynamics involved in the assembly process has been investigated with 3D electron microscopy, and molecular factors required for thylakoid construction have been characterized. The two classes of chloroplasts in C4 plants arise from common precursors, but little is known about how a single type of chloroplasts grow, divide, and differentiate to mature into distinct chloroplasts. Here, we outline the thylakoid structure and its assembly processes in C3 plants to discuss ultrastructural analyses of dimorphic chloroplast biogenesis in C4 plant species. Future directions for electron microscopy research of C4 photosynthetic systems are also proposed.
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Mai KKK, Yeung WT, Han SY, Cai X, Hwang I, Kang BH. Electron Tomography Analysis of Thylakoid Assembly and Fission in Chloroplasts of a Single-Cell C4 plant, Bienertia sinuspersici. Sci Rep 2019; 9:19640. [PMID: 31873131 PMCID: PMC6927967 DOI: 10.1038/s41598-019-56083-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/02/2019] [Indexed: 01/31/2023] Open
Abstract
Bienertia sinuspersici is a single-cell C4 plant species of which chlorenchyma cells have two distinct groups of chloroplasts spatially segregated in the cytoplasm. The central vacuole encloses most chloroplasts at the cell center and confines the rest of the chloroplasts near the plasma membrane. Young chlorenchyma cells, however, do not have large vacuoles and their chloroplasts are homogenous. Therefore, maturing Bienertia chlorenchyma cells provide a unique opportunity to investigate chloroplast proliferation in the central cluster and the remodeling of chloroplasts that have been displaced by the vacuole to the cell periphery. Chloroplast numbers and sizes increased, more notably, during later stages of maturation than the early stages. Electron tomography analyses indicated that chloroplast enlargement is sustained by thylakoid growth and that invaginations from the inner envelope membrane contributed to thylakoid assembly. Grana stacks acquired more layers, differentiating them from stroma thylakoids as central chloroplasts matured. In peripheral chloroplasts, however, grana stacks stretched out to a degree that the distinction between grana stacks and stroma thylakoids was obscured. In central chloroplasts undergoing division, thylakoids inside the cleavage furrow were kinked and severed. Grana stacks in the division zone were disrupted, and large complexes in their membranes were dislocated, suggesting the existence of a thylakoid fission machinery.
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Affiliation(s)
- Keith Ka Ki Mai
- Centre for Cell and Developmental Biology, State Key Laboratory for Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Wai-Tsun Yeung
- Centre for Cell and Developmental Biology, State Key Laboratory for Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Sang-Yun Han
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Xiaohao Cai
- Mullard Space Science laboratory, Holmbury St. Mary Dorking, Surrey, RH5 6NT, UK
| | - Inhwan Hwang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Byung-Ho Kang
- Centre for Cell and Developmental Biology, State Key Laboratory for Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
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Genetic Suppressor Screen Using an Inducible FREE1-RNAi Line to Detect ESCRT Genetic Interactors in Arabidopsis thaliana. Methods Mol Biol 2019. [PMID: 31250309 DOI: 10.1007/978-1-4939-9492-2_20] [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
FREE1 (FYVE domain protein required for endosomal sorting 1), a newly identified component of endosomal sorting complex required for transport I (ESCRT I), plays multiple roles in regulating protein trafficking and organelle biogenesis in Arabidopsis. Similar to other ESCRT components, FREE1 is essential for plant growth and development because free1 mutant is seedling lethal. To identify key components that genetically interact with FREE1, we performed forward genetic suppressor screening using a dexamethasone (DEX)-inducible FREE1-RNAi line. Here we describe the detailed protocol of identifying novel FREE1 regulators using an inducible FREE1-RNAi line for the genetic suppressor screen. This protocol represents a whole procedure for identifying ESCRT genetic interactors in Arabidopsis thaliana.
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Chemical Fixation, Immunofluorescence, and Immunogold Labeling of Electron Microscopical Sections. Methods Mol Biol 2019. [PMID: 31148030 DOI: 10.1007/978-1-4939-9469-4_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
Knowledge about the spatiotemporal distribution patterns of proteins and other molecules of the cell is essential for understanding their function. A widely used technique is immunolabeling which uses specific antibodies to reveal the distribution of molecular components at various structural levels. Immunofluorescence gives an overview about the distribution of molecules at the level of the fluorescence or confocal laser scanning microscope. Electron microscopy offers the highest resolution of morphological techniques and is thus an indispensable tool for the analysis of molecule distribution patterns at the subcellular level. In this chapter we describe selected routine methods for immunofluorescence and for labeling ultrathin sections of resin-embedded material with antibodies conjugated to colloidal gold, including protocols for chemical fixation, embedding, and sectioning.
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Hunziker P, Schulz A. Transmission Electron Microscopy of the Phloem with Minimal Artifacts. Methods Mol Biol 2019; 2014:17-27. [PMID: 31197783 DOI: 10.1007/978-1-4939-9562-2_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
It is a universal feature of seed plants that their phloem consists of a continuous sieve-tube system throughout the plant that is highly pressurized by its sugar contents. Cellular continuity and the pressure flow, osmotically generated in the source leaves, allow the assimilates to reach all sinks organs. However, both phloem features, the cellular continuity and the high pressure, are challenges when fixing the phloem for transmission electron microscopy. With very few exceptions, the tissue preparation necessary for the fixation evokes rapid wound responses that eventually result in artifacts.This chapter describes the steps necessary to minimize development of artifacts in the phloem and includes preparation of fixatives, a dissection procedure that optimizes penetration of the fixatives and application to axial and lateral plant organs. Moreover, as alternative to the established fixation of fresh hand sections, we suggest a xylem-assisted perfusion fixation method for herbaceous plants. After the initial fixation, the subsequent dehydration, embedding, and ultrathin sectioning of the material follow routine procedures, which are briefly discussed, as is the orientation of samples for obtaining transverse and longitudinal phloem sections.
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Affiliation(s)
- Pascal Hunziker
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Alexander Schulz
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.
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Mai KKK, Kang BH. Semiautomatic Segmentation of Plant Golgi Stacks in Electron Tomograms Using 3dmod. Methods Mol Biol 2017; 1662:97-104. [PMID: 28861820 DOI: 10.1007/978-1-4939-7262-3_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electron tomography is a powerful tool for visualizing subcellular organelles. With the advances in cryo-fixation techniques, it is now possible to reconstruct complex structures in cells preserved close to their native states in three-dimension (3D) using electron tomography. In order to better visualize these objects, 3D models are made from outlines of organelles in individual tomographic slices, which can be used to display morphological features and quantify structural parameters. While outlines of simple organelles can be drawn by hand fairly quickly, it is possible to accelerate 3D modeling of more complex organelles by means of semiautomatic segmentation. In this chapter, we use the example of reconstructing Golgi cisternae of a plant cell into 3D models using the semiautomatic protocol.
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Affiliation(s)
- Keith Ka Ki Mai
- State Key Laboratory of Agrobiotechnology, Centre for Cell and Developmental Biology, School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Byung-Ho Kang
- State Key Laboratory of Agrobiotechnology, Centre for Cell and Developmental Biology, School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China.
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Yim S, Khare D, Kang J, Hwang JU, Liang W, Martinoia E, Zhang D, Kang B, Lee Y. Postmeiotic development of pollen surface layers requires two Arabidopsis ABCG-type transporters. PLANT CELL REPORTS 2016; 35:1863-73. [PMID: 27271688 DOI: 10.1007/s00299-016-2001-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/23/2016] [Indexed: 05/02/2023]
Abstract
Two Arabidopsis ABC transporters, ABCG1 and ABCG16, are expressed in the tapetal layer, specifically after postmeiotic microspore release, and play important roles in pollen surface development. The male gametophytic cells of terrestrial plants, the pollen grains, travel far before fertilization, and thus require strong protective layers, which take the form of a pollen coat and a pollen wall. The protective surface structures are generated by the tapetum, the tissue surrounding the developing gametophytes. Many ABC transporters, including Arabidopsis thaliana ABCG1 and ABCG16, have been shown to play essential roles in the development of such protective layers. However, the details of the mechanism of their function remain to be clarified. In this study, we show that ABCG1 and ABCG16 are localized at the plasma membrane of tapetal cells, specifically after postmeiotic microspore release, and play critical roles in the postmeiotic stages of male gametophyte development. Consistent with this stage-specific expression, the abcg1 abcg16 double knockout mutant exhibited defects in pollen development after postmeiotic microspore release; their microspores lacked intact nexine and intine layers, exhibited defects in pollen mitosis I, displayed ectopic deposits of arabinogalactan proteins, failed to complete cytokinesis, and lacked sperm cells. Interestingly, the double mutant exhibited abnormalities in the internal structures of tapetal cells, too; the storage organelles of tapetal cells, tapetosomes and elaioplasts, were morphologically altered. Thus, this work reveals that the lack of ABCG1 and ABCG16 at the tapetal cell membrane causes a broad range of defects in pollen, as well as in tapetal cells themselves. Furthermore, these results suggest that normal pollen surface development is necessary for normal development of the pollen cytoplasm.
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Affiliation(s)
- Sojeong Yim
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Deepa Khare
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Joohyun Kang
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Jae-Ung Hwang
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Center for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Enrico Martinoia
- Department of Plant and Microbial Biology, University Zurich, 8008, Zurich, Switzerland
| | - Dabing Zhang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Center for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Byungho Kang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Youngsook Lee
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea.
- Division of Integrative Biosciences and Biotechnology, POSTECH, Pohang, 37673, Korea.
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Immunoelectron Microscopy of Cryofixed and Freeze-Substituted Plant Tissues. Methods Mol Biol 2016. [PMID: 27515084 DOI: 10.1007/978-1-4939-6352-2_14] [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
Cryofixation and freeze-substitution techniques provide excellent preservation of plant ultrastructure. The advantage of cryofixation is not only in structural preservation, as seen in the smooth plasma membrane, but also in the speed in arresting cell activity. Immunoelectron microscopy reveals the subcellular localization of molecules within cells. Immunolabeling in combination with cryofixation and freeze-substitution techniques provides more detailed information on the immunoelectron-microscopic localization of molecules in the plant cell than can be obtained from chemically fixed tissues. Here, we introduce methods for immunoelectron microscopy of cryofixed and freeze-substituted plant tissues.
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