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Zhuang X, Li R, Jiang L. A century journey of organelles research in the plant endomembrane system. THE PLANT CELL 2024; 36:1312-1333. [PMID: 38226685 PMCID: PMC11062446 DOI: 10.1093/plcell/koae004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/14/2023] [Accepted: 01/09/2024] [Indexed: 01/17/2024]
Abstract
We are entering an exciting century in the study of the plant organelles in the endomembrane system. Over the past century, especially within the past 50 years, tremendous advancements have been made in the complex plant cell to generate a much clearer and informative picture of plant organelles, including the molecular/morphological features, dynamic/spatial behavior, and physiological functions. Importantly, all these discoveries and achievements in the identification and characterization of organelles in the endomembrane system would not have been possible without: (1) the innovations and timely applications of various state-of-art cell biology tools and technologies for organelle biology research; (2) the continuous efforts in developing and characterizing new organelle markers by the plant biology community; and (3) the landmark studies on the identification and characterization of the elusive organelles. While molecular aspects and results for individual organelles have been extensively reviewed, the development of the techniques for organelle research in plant cell biology is less appreciated. As one of the ASPB Centennial Reviews on "organelle biology," here we aim to take a journey across a century of organelle biology research in plants by highlighting the important tools (or landmark technologies) and key scientists that contributed to visualize organelles. We then highlight the landmark studies leading to the identification and characterization of individual organelles in the plant endomembrane systems.
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Affiliation(s)
- Xiaohong Zhuang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Ruixi Li
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- Institute of Plant Molecular Biology and Agricultural Biotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
- CUHK Shenzhen Research Institute, Shenzhen 518057, China
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2
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Yanagisawa M, Chuong SDX. Chloroplast Envelopes Play a Role in the Formation of Autophagy-Related Structures in Plants. PLANTS (BASEL, SWITZERLAND) 2023; 12:443. [PMID: 36771525 PMCID: PMC9920391 DOI: 10.3390/plants12030443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Autophagy is a degradation process of cytoplasmic components that is conserved in eukaryotes. One of the hallmark features of autophagy is the formation of double-membrane structures known as autophagosomes, which enclose cytoplasmic content destined for degradation. Although the membrane source for the formation of autophagosomes remains to be determined, recent studies indicate the involvement of various organelles in autophagosome biogenesis. In this study, we examined the autophagy process in Bienertia sinuspersici: one of four terrestrial plants capable of performing C4 photosynthesis in a single cell (single-cell C4 species). We demonstrated that narrow tubules (stromule-like structures) 30-50 nm in diameter appear to extend from chloroplasts to form the membrane-bound structures (autophagosomes or autophagy-related structures) in chlorenchyma cells of B. sinuspersici during senescence and under oxidative stress. Immunoelectron microscopic analysis revealed the localization of stromal proteins to the stromule-like structures, sequestering portions of the cytoplasm in chlorenchyma cells of oxidative stress-treated leaves of B. sinuspersici and Arabidopsis thaliana. Moreover, the fluorescent marker for autophagosomes GFP-ATG8, colocalized with the autophagic vacuole maker neutral red in punctate structures in close proximity to the chloroplasts of cells under oxidative stress conditions. Together our results implicate a role for chloroplast envelopes in the autophagy process induced during senescence or under certain stress conditions in plants.
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3
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Shimizu Y, Uemura T. The sorting of cargo proteins in the plant trans-Golgi network. FRONTIERS IN PLANT SCIENCE 2022; 13:957995. [PMID: 36035717 PMCID: PMC9402974 DOI: 10.3389/fpls.2022.957995] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/20/2022] [Indexed: 06/01/2023]
Abstract
Membrane trafficking contributes to distinct protein compositions of organelles and is essential for proper organellar maintenance and functions. The trans-Golgi network (TGN) acts as a sorting station where various cargo proteins are sorted and directed to post-Golgi compartments, such as the multivesicular body or pre-vacuolar compartment, vacuoles, and plasma membrane. The spatial and temporal segregation of cargo proteins within the TGN, which is mediated with different sets of regulators including small GTPases and cargo adaptors, is a fundamental process in the sorting machinery. Recent studies with powerful imaging technologies have suggested that the TGN possesses spatially distinct subdomains or zones for different trafficking pathways. In this review, we will summarize the spatially and dynamically characteristic features of the plant TGN and their relation to cargo protein trafficking.
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Affiliation(s)
- Yutaro Shimizu
- RIKEN Center for Sustainable Resource Science, Wako, Saitama, Japan
| | - Tomohiro Uemura
- Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo-ku, Tokyo, Japan
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4
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Cao W, Li Z, Huang S, Shi Y, Zhu Y, Lai MN, Lok PL, Wang X, Cui Y, Jiang L. Correlation of vacuole morphology with stomatal lineage development by whole-cell electron tomography. PLANT PHYSIOLOGY 2022; 188:2085-2100. [PMID: 35134219 PMCID: PMC8968265 DOI: 10.1093/plphys/kiac028] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/22/2021] [Indexed: 05/26/2023]
Abstract
Stomatal movement is essential for plants to optimize transpiration and therefore photosynthesis. Rapid changes in the stomatal aperture are accompanied by adjustment of vacuole volume and morphology in guard cells (GCs). In Arabidopsis (Arabidopsis thaliana) leaf epidermis, stomatal development undergoes a cell-fate transition including four stomatal lineage cells: meristemoid, guard mother cell, young GC, and GC. Little is known about the mechanism underlying vacuole dynamics and vacuole formation during stomatal development. Here, we utilized whole-cell electron tomography (ET) analysis to elucidate vacuole morphology, formation, and development in different stages of stomatal lineage cells at nanometer resolution. The whole-cell ET models demonstrated that large vacuoles were generated from small vacuole stepwise fusion/maturation along stomatal development stages. Further ET analyses verified the existence of swollen intraluminal vesicles inside distinct vacuoles at certain developmental stages of stomatal lineage cells, implying a role of multivesicular body fusion in stomatal vacuole formation. Collectively, our findings demonstrate a mechanism mediating vacuole formation in Arabidopsis stomatal development and may shed light on the role of vacuoles in stomatal movement.
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Affiliation(s)
- Wenhan Cao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Zhenping Li
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Shuxian Huang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yuwei Shi
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Ying Zhu
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Man Nga Lai
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Pui Lok Lok
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Xiangfeng Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yong Cui
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
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Gonçalves JR, Rocha DI, Dos Santos LS, Dalvi VC. The short but useful life of Prepusa montana Mart. (Gentianaceae Juss.) leaf colleters-anatomical, micromorphological, and ultrastructural aspects. PROTOPLASMA 2022; 259:187-201. [PMID: 33938994 DOI: 10.1007/s00709-021-01651-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
Colleters are secretory structures involved in the protection of young and developing plant organs. Although the presence of colleters in Gentianales is described as a synapomorphy, studies on the morphofunctionality of colleters and the mechanisms underlying the synthesis and release of colleter secretion in Gentianaceae are scarce. Here, we described the ontogeny and the morphological and functional aspects of colleters of Prepusa montana, revealed the nature of the key compounds present in the secretion, and explored the cellular aspects of the synthesis and release of secretion and senescence of colleters. Samples of the stem apical meristem with leaf primordium and young leaves; adult and senescent leaves were observed using light and electron microscopy. The colleters, located in the axil of the leaf, have a protodermal origin and develop asynchronously. They are digitiform, possessing a short peduncle and a secretory head containing homogeneous cells with dense cytoplasm and abundant endoplasmic reticulum and Golgi bodies. The secretion, composed of polysaccharides and proteins, is accumulated in schizogenous spaces and released through the separation of peripheral secretory cells and loosening of the external periclinal wall. Presumably, senescence is caused by programmed cell death. The morphoanatomical characterization of P. montana leaf colleters described here is the first record for the genus and the peculiar accumulation of colleter secretion in schizogenous spaces expanding our knowledge on the diversity of these secretory structures. Our results also provide insights into programmed cell death as an eminent topic related to secretory structures.
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Affiliation(s)
- Jailma Rodrigues Gonçalves
- Instituto Federal de Educação, Ciência e Tecnologia Goiano (IF Goiano, Campus Rio Verde), Rodovia Sul Goiana, Km 01, Zona Rural, Rio Verde, Goiás, CEP 75901-970, Brazil
| | - Diego Ismael Rocha
- Departamento de Agronomia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, CEP 36570-900, Brazil
| | - Luana Silva Dos Santos
- Instituto Federal de Educação, Ciência e Tecnologia Goiano (IF Goiano, Campus Rio Verde), Rodovia Sul Goiana, Km 01, Zona Rural, Rio Verde, Goiás, CEP 75901-970, Brazil
| | - Valdnéa Casagrande Dalvi
- Instituto Federal de Educação, Ciência e Tecnologia Goiano (IF Goiano, Campus Rio Verde), Rodovia Sul Goiana, Km 01, Zona Rural, Rio Verde, Goiás, CEP 75901-970, Brazil.
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Robert G, Yagyu M, Lascano HR, Masclaux-Daubresse C, Yoshimoto K. A proposed role for endomembrane trafficking processes in regulating tonoplast content and vacuole dynamics under ammonium stress conditions in Arabidopsis root cells. PLANT SIGNALING & BEHAVIOR 2021; 16:1924977. [PMID: 33955336 PMCID: PMC8280891 DOI: 10.1080/15592324.2021.1924977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
Ammonium (NH4+) stress has multiple effects on plant physiology, therefore, plant responses are complex, and multiple mechanisms are involved in NH4+ sensitivity and tolerance in plants. Root growth inhibition is an important quantitative readout of the effects of NH4+ stress on plant physiology, and cell elongation appear as the principal growth inhibition target. We recently proposed autophagy as a relevant physiological mechanisms underlying NH4+ sensitivity response in Arabidopsis. In a brief overview, the impaired macro-autophagic flux observed under NH4+ stress conditions has a detrimental impact on the cellular energetic balance, and therefore on the energy-demanding plant growth. In contrast to its inhibitory effect on the autophagosomes flux to vacuole, NH4+ toxicity induced a micro-autophagy-like process. Consistent with the reduced membrane flux to the vacuole related to macro-autophagy inhibition and the increased tonoplast degradation due to enhanced micro-autophagy, the vacuoles of the root cells of the NH4+-stressed plants showed lower tonoplast content and a decreased perimeter/area ratio. As the endosome-to-vacuole trafficking is another important process that contributes to membrane flux toward the vacuole, we evaluated the effects of NH4+ stress on this process. This allows us to propose that autophagy could contribute to vacuole development as well as possible avenues to follow for future studies.
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Affiliation(s)
- Germán Robert
- Plant Stress Biology Group, Unidad de Doble Dependencia INTA-CONICET (UDEA), Córdoba, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Fisiología y Recursos Genéticos Vegetales (IFRGV), Córdoba, Argentina
- Cátedra de Fisiología Vegetal, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mako Yagyu
- Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
| | - Hernán Ramiro Lascano
- Plant Stress Biology Group, Unidad de Doble Dependencia INTA-CONICET (UDEA), Córdoba, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Fisiología y Recursos Genéticos Vegetales (IFRGV), Córdoba, Argentina
- Cátedra de Fisiología Vegetal, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | | | - Kohki Yoshimoto
- Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
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Cui Y, Zhao Q, Hu S, Jiang L. Vacuole Biogenesis in Plants: How Many Vacuoles, How Many Models? TRENDS IN PLANT SCIENCE 2020; 25:538-548. [PMID: 32407694 DOI: 10.1016/j.tplants.2020.01.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 01/19/2020] [Accepted: 01/27/2020] [Indexed: 05/22/2023]
Abstract
Vacuoles are the largest membrane-bounded organelles and have essential roles in plant growth and development, but several important questions on the biogenesis and dynamics of lytic vacuoles (LVs) remain. Here, we summarize and discuss recent research and models of vacuole formation, and propose, with testable hypotheses, that besides inherited vacuoles, plant cells can also synthesize LVs de novo from multiple organelles and routes in response to growth and development or external factors. Therefore, LVs may be further classified into different subgroups and/or populations with different pH, cargos, and functions, among which multivesicular body (MVB)-derived small vacuoles are the main source for central vacuole formation in arabidopsis root cortical cells.
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Affiliation(s)
- Yong Cui
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
| | - Qiong Zhao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Shuai Hu
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; CUHK Shenzhen Research Institute, Shenzhen 518057, China.
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Fang X, Zhang Y, Wang M, Li P, Zhang Q, Si J, Wei B, Miao Y, Tian L, Cai X. Lysosome and proteasome pathways are distributed in laticifers of Euphorbia helioscopia L. PHYSIOLOGIA PLANTARUM 2019; 166:1026-1038. [PMID: 30414186 DOI: 10.1111/ppl.12869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 10/31/2018] [Accepted: 11/02/2018] [Indexed: 06/08/2023]
Abstract
At present, the lysosome pathway (LP) and proteasome pathway (PP) are known as major clearance systems in eukaryotic cells. The laticifer, a secretory tissue, degrades some cytoplasm during development. In this study, we investigated the distribution of LP and PP in non-articulated laticifers of Euphorbia helioscopia L. Electron microscopy revealed that, plastids, mitochondria and some cyotsol were degraded in the late development laticifers, where there were numerous vesicles originated from dicytosomes. Accordingly, some key proteins in LP and PP were detected in E. helioscopia latex using isobaric tags for relative and absolute quantitation (iTRAQ) proteomics. Further immunohistochemistry analysis revealed that the clathrin heavy chain (CHC) belonging to LP and the ubiquitin-mediated proteasome degradation increases gradually as the laticifer develops. Immuno-electron microscopy revealed that the cysteine protease, CHC and AP-2 complex subunit beta-1 belonging to LP were mainly distributed in vesicles deriving from dicytosomes, which we called lysosome-like vesicles. Ubiquitin was widely distributed in the cytosol, and proteasome activity was significantly reduced when various concentrations of the inhibitor MG132 were added to the latex total protein. We hypothesize that LP and PP are distributed in E. helioscopia laticifers; and it was speculated that LP and PP might be involved in the degradation of organelles and some cytoplasmic matrix in E. helioscopia laticifers.
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Affiliation(s)
- Xiaoai Fang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Yue Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Meng Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Peng Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Qing Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Jingjing Si
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Bofei Wei
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Yan Miao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Lanting Tian
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Xia Cai
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
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Machado SR, Rodrigues TM. Autophagy and vacuolar biogenesis during the nectary development. PLANTA 2019; 250:519-533. [PMID: 31104130 DOI: 10.1007/s00425-019-03190-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/14/2019] [Indexed: 05/26/2023]
Abstract
Different autophagy pathways are a driver of vacuolar biogenesis and are development stage specific during the extrafloral nectary development in Citharexylum myrianthum. Plant autophagy plays an important role in various developmental processes such as seed germination, pollen maturation and leaf senescence. However, studies that address the evidence of autophagy and its role in the development of plant glands are scarce and largely restricted to laticifers. Regarding nectary, studies have repeatedly pointed to signs of degradation associated with the end of the secretory cycle, without exploring autophagy. Likewise, the relationship between autophagy and biogenesis of vacuoles remains an unexplored issue. In this study, using conventional and microwave fixation in association with ultracytochemical methods for transmission electron microscopy, we investigated the occurrence of autophagy and its implication in the differentiation of extrafloral nectary in Citharexylum myrianthum (Verbenaceae) under natural conditions, focusing on the vacuole biogenesis. We described a variety of vacuole types associated with the stage of nectary epidermis development, which differs with respect to origin, function and nature of the products to be stored. Three distinct autophagy pathways were detected: macroautophagy, microautophagy (both restricted to the undifferentiated epidermal cells, at the presecretory stage) and megaautophagy (circumscribed to the differentiated epidermal cells, at the postsecretory stage). Our study clearly demonstrated that the vacuole variety and autophagy processes in the nectary epidermal cells are development specific. This study highlights the role of autophagy in vacuole biogenesis and its implications for the development of nectary and opens new venues for future studies on regulation mechanisms for autophagy in plant secretory structures under normal conditions.
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Affiliation(s)
- Silvia R Machado
- Department of Botany, Institute of Biosciences of Botucatu (IBB), São Paulo State University (UNESP), Botucatu City, SP, Brazil.
- Center of Electron Microscopy (CME), Institute of Biosciences of Botucatu (IBB), São Paulo State University (UNESP), Botucatu City, SP, Brazil.
| | - Tatiane M Rodrigues
- Department of Botany, Institute of Biosciences of Botucatu (IBB), São Paulo State University (UNESP), Botucatu City, SP, Brazil
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Marinho CR, Teixeira SP. Cellulases and pectinases act together on the development of articulated laticifers in Ficus montana and Maclura tinctoria (Moraceae). PROTOPLASMA 2019; 256:1093-1107. [PMID: 30927084 DOI: 10.1007/s00709-019-01367-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
The presence of articulated laticifers in the Moraceae family was recently discovered, which means that the location of pectinase and cellulase activities must be of great importance for their growth. Thus, the present study aimed to determine the role of these enzymes in the laticifer growth in Ficus montana and Maclura tinctoria. Reproductive meristems were collected and fixed in Karnovsky. Pectinase and cellulase labeling was performed in part of the samples, while another part was processed for usual TEM analyses. Pectinase and cellulase activities were detected in the vacuole and close to the middle lamella in both species. The presence of cellulases in the laticifers supports their articulated origin. Therefore, the occurrence of pectinase and cellulase activity in the laticifers points out that these enzymes could act in the dissolution of the transverse walls and in the processes of intrusive growth (through the dissolution of the middle lamella) and cell elongation (through the partial disassembly of components of the wall making it more plastic). Both enzymes are synthesized in the endoplasmic reticulum and transported to the cell wall by exocytosis or stored in the vacuole. The species studied showed a diverse subcellular composition, which is probably related to the species and not to the laticifer type (they present the same type) and to the composition of the latex (they show similar latex composition). We conclude that the presence of pectinases and cellulases can be used as a diagnostic condition for the laticifer types (articulated vs. non-articulated).
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Affiliation(s)
- Cristina Ribeiro Marinho
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café s/n, Ribeirao Preto, SP, 14040-903, Brazil
| | - Simone Pádua Teixeira
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café s/n, Ribeirao Preto, SP, 14040-903, Brazil.
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11
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Fan J, Yu L, Xu C. Dual Role for Autophagy in Lipid Metabolism in Arabidopsis. THE PLANT CELL 2019; 31:1598-1613. [PMID: 31036588 PMCID: PMC6635848 DOI: 10.1105/tpc.19.00170] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 03/26/2019] [Accepted: 04/19/2019] [Indexed: 05/18/2023]
Abstract
Autophagy is a major catabolic pathway whereby cytoplasmic constituents including lipid droplets (LDs), storage compartments for neutral lipids, are delivered to the lysosome or vacuole for degradation. The autophagic degradation of cytosolic LDs, a process termed lipophagy, has been extensively studied in yeast and mammals, but little is known about the role for autophagy in lipid metabolism in plants. Organisms maintain a basal level of autophagy under favorable conditions and upregulate the autophagic activity under stress including starvation. Here, we demonstrate that Arabidopsis (Arabidopsis thaliana) basal autophagy contributes to triacylglycerol (TAG) synthesis, whereas inducible autophagy contributes to LD degradation. We found that disruption of basal autophagy impedes organellar membrane lipid turnover and hence fatty acid mobilization from membrane lipids to TAG. We show that lipophagy is induced under starvation as indicated by colocalization of LDs with the autophagic marker and the presence of LDs in vacuoles. We additionally show that lipophagy occurs in a process morphologically resembling microlipophagy and requires the core components of the macroautophagic machinery. Together, this study provides mechanistic insight into lipophagy and reveals a dual role for autophagy in regulating lipid synthesis and turnover in plants.
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Affiliation(s)
- Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Linhui Yu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
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12
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Haddad IVN, de Sá-Haiad B, de Santiago-Fernandes LDR, Machado SR. Pollen grain development and male sterility in the perfect flowers of Maytenus obtusifolia Mart. (Celastraceae). PROTOPLASMA 2019; 256:745-761. [PMID: 30554375 DOI: 10.1007/s00709-018-01336-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 12/03/2018] [Indexed: 06/09/2023]
Abstract
Perfect flowers of Maytenus obtusifolia have partial sterility of pollen grains, resulting in collapsed and developed free microspores. However, the cellular events resulting in partial male sterility have not been determined. In pistillate flowers of this species, male sterility is related to the premature programmed cell death (PCD) in tapetum and sporogenic cells. The process occurs through autophagy via macroautophagy and massive autophagy and is associated with sporophytic cytoplasmic male sterility (CMS). Here, we characterised the development of pollen grains and investigated the cellular events that result in tapetum cells and free microspores PCD in perfect flowers, using light and transmission electron microscopy combined with the TUNEL (Terminal deoxynucleotidyl transferase mediated dUDP end-Labeling) assay and the ZIO (Zinc iodide-osmium tetroxide) method. Pollen grain development in perfect flowers was divided into eight developmental stages based on the characteristics of the pollen grains. Tapetum cells undergo PCD at the free microspore stage, through a macroautophagic process, by formation of autophagosomes and by autophagosomes giving rise to lytic vacuoles at maturity. In the final stage of PCD, massive autophagy occurs by rupture of the tonoplast. The development of viable and inviable microspores diverges at the vacuolated microspore stage, when PCD occurs in some free microspores, causing interruption of pollen development through necrosis. These events result in the observed partial male sterility. Viable microspores undergo mitosis and develop into tricellular pollen grains. Male sterility in hermaphrodite individuals is here interpreted as gametophytic CMS.
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Affiliation(s)
| | - Bárbara de Sá-Haiad
- Departamento de Botânica, Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 22940-040, Brazil
| | | | - Silvia Rodrigues Machado
- Departamento de Botânica, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP, 18618-000, Brazil
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13
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Baranowski Ł, Różańska E, Sańko-Sawczenko I, Matuszkiewicz M, Znojek E, Filipecki M, Grundler FMW, Sobczak M. Arabidopsis tonoplast intrinsic protein and vacuolar H +-adenosinetriphosphatase reflect vacuole dynamics during development of syncytia induced by the beet cyst nematode Heterodera schachtii. PROTOPLASMA 2019; 256:419-429. [PMID: 30187342 PMCID: PMC6510842 DOI: 10.1007/s00709-018-1303-4] [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: 03/12/2018] [Accepted: 08/24/2018] [Indexed: 05/20/2023]
Abstract
Plant parasitic cyst nematodes induce specific hypermetabolic syncytial nurse cell structures in host roots. A characteristic feature of syncytia is the lack of the central vacuole and the formation of numerous small and larger vesicles. We show that these structures are formed de novo via widening of ER cisternae during the entire development of syncytium, whereas in advanced stages of syncytium development, larger vacuoles are also formed via fusion of vesicles/tubules surrounding organelle-free pre-vacuole regions. Immunogold transmission electron microscopy of syncytia localised the vacuolar markers E subunit of vacuolar H+-adenosinetriphosphatase (V-ATPase) complex and tonoplast intrinsic protein (γ-TIP1;1) mostly in membranes surrounding syncytial vesicles, thus indicating that these structures are vacuoles and that some of them have a lytic character. To study the function of syncytial vacuoles, changes in expression of AtVHA-B1, AtVHA-B2 and AtVHA-B3 (coding for isoforms of subunit B of V-ATPase), and TIP1;1 and TIP1;2 (coding for γ-TIP proteins) genes were analysed. RT-qPCR revealed significant downregulation of AtVHA-B2, TIP1;1 and TIP1;2 at the examined stages of syncytium development compared to uninfected roots. Expression of VHA-B1 and VHA-B3 decreased at 3 dpi but reached the level of control at 7 dpi. These results were confirmed for TIP1;1 by monitoring At-γ-TIP-YFP reporter construct expression. Infection test conducted on tip1;1 mutant plants showed formation of larger syncytia and higher numbers of females in comparison to wild-type plants indicating that reduced levels or lack of TIP1;1 protein promote nematode development.
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Affiliation(s)
- Łukasz Baranowski
- Department of Botany, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-766, Warsaw, Poland
| | - Elżbieta Różańska
- Department of Botany, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-766, Warsaw, Poland
| | - Izabela Sańko-Sawczenko
- Department of Botany, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-766, Warsaw, Poland
| | - Mateusz Matuszkiewicz
- Department of Plant Genetics, Breeding and Biotechnology, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-766, Warsaw, Poland
| | - Ewa Znojek
- Department of Botany, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-766, Warsaw, Poland
| | - Marcin Filipecki
- Department of Plant Genetics, Breeding and Biotechnology, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-766, Warsaw, Poland
| | - Florian M W Grundler
- INRES - Molecular Phytomedicine, Rheinische Friedrich-Wilhelms-University of Bonn, Karlrobert-Kreiten-Straße 13, 53115, Bonn, Germany
| | - Mirosław Sobczak
- Department of Botany, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-766, Warsaw, Poland.
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14
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Cui Y, Cao W, He Y, Zhao Q, Wakazaki M, Zhuang X, Gao J, Zeng Y, Gao C, Ding Y, Wong HY, Wong WS, Lam HK, Wang P, Ueda T, Rojas-Pierce M, Toyooka K, Kang BH, Jiang L. A whole-cell electron tomography model of vacuole biogenesis in Arabidopsis root cells. NATURE PLANTS 2019; 5:95-105. [PMID: 30559414 DOI: 10.1038/s41477-018-0328-1] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 11/14/2018] [Indexed: 05/20/2023]
Abstract
Plant vacuoles are dynamic organelles that play essential roles in regulating growth and development. Two distinct models of vacuole biogenesis have been proposed: separate vacuoles are formed by the fusion of endosomes, or the single interconnected vacuole is derived from the endoplasmic reticulum. These two models are based on studies of two-dimensional (2D) transmission electron microscopy and 3D confocal imaging, respectively. Here, we performed 3D electron tomography at nanometre resolution to illustrate vacuole biogenesis in Arabidopsis root cells. The whole-cell electron tomography analysis first identified unique small vacuoles (SVs; 400-1,000 nm in diameter) as nascent vacuoles in early developmental cortical cells. These SVs contained intraluminal vesicles and were mainly derived/matured from multivesicular body (MVB) fusion. The whole-cell vacuole models and statistical analysis on wild-type root cells of different vacuole developmental stages demonstrated that central vacuoles were derived from MVB-to-SV transition and subsequent fusions of SVs. Further electron tomography analysis on mutants defective in MVB formation/maturation or vacuole fusion demonstrated that central vacuole formation required functional MVBs and membrane fusion machineries.
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Affiliation(s)
- Yong Cui
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
| | - Wenhan Cao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yilin He
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Qiong Zhao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Mayumi Wakazaki
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Xiaohong Zhuang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Jiayang Gao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yonglun Zeng
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Caiji Gao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yu Ding
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- Department of Food Science & Technology, School of Science and Technology, Jinan University, Guangzhou, China
| | - Hiu Yan Wong
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Wing Shing Wong
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Ham Karen Lam
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Pengfei Wang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Takashi Ueda
- Division of Cellular Dynamics, National Institute for Basic Biology, Okazaki, Japan
| | - Marcela Rojas-Pierce
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, USA
| | | | - Byung-Ho Kang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
- The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, China.
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15
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Cui Y, Cao W, He Y, Zhao Q, Wakazaki M, Zhuang X, Gao J, Zeng Y, Gao C, Ding Y, Wong HY, Wong WS, Lam HK, Wang P, Ueda T, Rojas-Pierce M, Toyooka K, Kang BH, Jiang L. A whole-cell electron tomography model of vacuole biogenesis in Arabidopsis root cells. NATURE PLANTS 2019; 5:95-105. [PMID: 30559414 DOI: 10.1038/s41477-018-0328-321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 11/14/2018] [Indexed: 05/28/2023]
Abstract
Plant vacuoles are dynamic organelles that play essential roles in regulating growth and development. Two distinct models of vacuole biogenesis have been proposed: separate vacuoles are formed by the fusion of endosomes, or the single interconnected vacuole is derived from the endoplasmic reticulum. These two models are based on studies of two-dimensional (2D) transmission electron microscopy and 3D confocal imaging, respectively. Here, we performed 3D electron tomography at nanometre resolution to illustrate vacuole biogenesis in Arabidopsis root cells. The whole-cell electron tomography analysis first identified unique small vacuoles (SVs; 400-1,000 nm in diameter) as nascent vacuoles in early developmental cortical cells. These SVs contained intraluminal vesicles and were mainly derived/matured from multivesicular body (MVB) fusion. The whole-cell vacuole models and statistical analysis on wild-type root cells of different vacuole developmental stages demonstrated that central vacuoles were derived from MVB-to-SV transition and subsequent fusions of SVs. Further electron tomography analysis on mutants defective in MVB formation/maturation or vacuole fusion demonstrated that central vacuole formation required functional MVBs and membrane fusion machineries.
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Affiliation(s)
- Yong Cui
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
| | - Wenhan Cao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yilin He
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Qiong Zhao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Mayumi Wakazaki
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Xiaohong Zhuang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Jiayang Gao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yonglun Zeng
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Caiji Gao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yu Ding
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- Department of Food Science & Technology, School of Science and Technology, Jinan University, Guangzhou, China
| | - Hiu Yan Wong
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Wing Shing Wong
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Ham Karen Lam
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Pengfei Wang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Takashi Ueda
- Division of Cellular Dynamics, National Institute for Basic Biology, Okazaki, Japan
| | - Marcela Rojas-Pierce
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, USA
| | | | - Byung-Ho Kang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
- The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, China.
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16
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Di Sansebastiano GP, Barozzi F, Piro G, Denecke J, de Marcos Lousa C. Trafficking routes to the plant vacuole: connecting alternative and classical pathways. JOURNAL OF EXPERIMENTAL BOTANY 2017; 69:79-90. [PMID: 29096031 DOI: 10.1093/jxb/erx376] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/27/2017] [Indexed: 05/02/2023]
Abstract
Due to the numerous roles plant vacuoles play in cell homeostasis, detoxification, and protein storage, the trafficking pathways to this organelle have been extensively studied. Recent evidence, however, suggests that our vision of transport to the vacuole is not as simple as previously imagined. Alternative routes have been identified and are being characterized. Intricate interconnections between routes seem to occur in various cases, complicating the interpretation of data. In this review, we aim to summarize the published evidence and link the emerging data with previous findings. We discuss the current state of information on alternative and classical trafficking routes to the plant vacuole.
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Affiliation(s)
- Gian Pietro Di Sansebastiano
- DiSTeBA (Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali), University of Salento, Campus ECOTEKNE, Italy
| | - Fabrizio Barozzi
- DiSTeBA (Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali), University of Salento, Campus ECOTEKNE, Italy
| | - Gabriella Piro
- DiSTeBA (Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali), University of Salento, Campus ECOTEKNE, Italy
| | | | - Carine de Marcos Lousa
- Centre for Plant Sciences, Leeds University, UK
- Leeds Beckett University, School of Applied and Clinical Sciences, UK
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17
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Krüger F, Schumacher K. Pumping up the volume - vacuole biogenesis in Arabidopsis thaliana. Semin Cell Dev Biol 2017; 80:106-112. [PMID: 28694113 DOI: 10.1016/j.semcdb.2017.07.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 07/06/2017] [Accepted: 07/06/2017] [Indexed: 01/05/2023]
Abstract
Plant architecture follows the need to collect CO2, solar energy, water and mineral nutrients via large surface areas. It is by the presence of a central vacuole that fills much of the cell volume that plants manage to grow at low metabolic cost. In addition vacuoles buffer the fluctuating supply of essential nutrients and help to detoxify the cytosol when plants are challenged by harmful molecules. Despite their large size and multiple important functions, our knowledge of vacuole biogenesis and the machinery underlying their amazing dynamics is still fragmentary. In this review, we try to reconcile past and present models for vacuole biogenesis with the current knowledge of multiple parallel vacuolar trafficking pathways and the molecular machineries driving membrane fusion and organelle shape.
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Affiliation(s)
- Falco Krüger
- Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, DE-69120 Heidelberg, Germany
| | - Karin Schumacher
- Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, DE-69120 Heidelberg, Germany.
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18
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Paradas WC, Tavares Salgado L, Pereira RC, Hellio C, Atella GC, de Lima Moreira D, do Carmo APB, Soares AR, Menezes Amado-Filho G. A Novel Antifouling Defense Strategy from Red Seaweed: Exocytosis and Deposition of Fatty Acid Derivatives at the Cell Wall Surface. PLANT & CELL PHYSIOLOGY 2016; 57:1008-1019. [PMID: 26936789 DOI: 10.1093/pcp/pcw039] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/16/2016] [Indexed: 06/05/2023]
Abstract
We investigated the organelles involved in the biosynthesis of fatty acid (FA) derivatives in the cortical cells of Laurencia translucida (Rhodophyta) and the effect of these compounds as antifouling (AF) agents. A bluish autofluorescence (with emission at 500 nm) within L. translucida cortical cells was observed above the thallus surface via laser scanning confocal microscopy (LSCM). A hexanic extract (HE) from L. translucida was split into two isolated fractions called hydrocarbon (HC) and lipid (LI), which were subjected to HPLC coupled to a fluorescence detector, and the same autofluorescence pattern as observed by LSCM analyses (emission at 500 nm) was revealed in the LI fraction. These fractions were analyzed by gas chromatography-mass spectrometry (GC-MS), which revealed that docosane is the primary constituent of HC, and hexadecanoic acid and cholesterol trimethylsilyl ether are the primary components of LI. Nile red (NR) labeling (lipid fluorochrome) presented a similar cellular localization to that of the autofluorescent molecules. Transmission and scanning electron microscopy (TEM and SEM) revealed vesicle transport processes involving small electron-lucent vesicles, from vacuoles to the inner cell wall. Both fractions (HC and LI) inhibited micro-fouling [HC, lower minimum inhibitory concentration (MIC) values of 0.1 µg ml(-1); LI, lower MIC value of 10 µg ml(-1)]. The results suggested that L. translucida cortical cells can produce FA derivatives (e.g. HCs and FAs) and secrete them to the thallus surface, providing a unique and novel protective mechanism against microfouling colonization in red algae.
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Affiliation(s)
- Wladimir Costa Paradas
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, 22460-030, Brazil
| | - Leonardo Tavares Salgado
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, 22460-030, Brazil
| | - Renato Crespo Pereira
- Departamento de Biologia Marinha, Universidade Federal Fluminense, Niterói, 100644, Brazil
| | - Claire Hellio
- Biodimar/LEMAR/IUEM, Université de Bretagne Occidentale (UBO), 6 Avenue Victor Le Gorgeu, CS93837, Brest cedex 3 29238, France
| | - Georgia Correa Atella
- Departamento de Bioquimica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-590, Brazil
| | - Davyson de Lima Moreira
- Instituto de Tecnologia em Fármacos, Instituto Oswaldo Cruz, Rio de Janeiro, 21041-250, Brazil
| | | | - Angélica Ribeiro Soares
- Núcleo de Pesquisas em Ecologia e Desenvolvimento Social de Macaé, Universidade Federal do Rio de Janeiro, Macaé, 27910-970, Brazil
| | - Gilberto Menezes Amado-Filho
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, 22460-030, Brazil
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19
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Fleurat-Lessard P, Béré E, Lallemand M, Dédaldéchamp F, Roblin G. Co-occurrence of tannin and tannin-less vacuoles in sensitive plants. PROTOPLASMA 2016; 253:821-834. [PMID: 26103934 DOI: 10.1007/s00709-015-0844-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 06/08/2015] [Indexed: 05/23/2023]
Abstract
Vacuoles of different types frequently coexist in the same plant cell, but the duality of the tannin/tannin-less vacuoles observed in Mimosa pudica L. is rare. In this plant, which is characterized by highly motile leaves, the development and original features of the double vacuolar compartment were detailed in primary pulvini from the young to the mature leaf stage. In young pulvini, the differentiation of tannin vacuoles first occurred in the epidermis and progressively spread toward the inner cortex. In motor cells of nonmotile pulvini, tannin deposits first lined the membranes of small vacuole profiles and then formed opaque clusters that joined together to form a large tannin vacuole (TV), the proportion of which in the cell was approximately 45%. At this stage, transparent vacuole profiles were rare and small, but as the parenchyma cells enlarged, these profiles coalesced to form a transparent vacuole with a convexity toward the larger-sized tannin vacuole. When leaf motility began to occur, the two vacuole types reached the same relative proportion (approximately 30%). Finally, in mature cells displaying maximum motility, the large transparent colloidal vacuole (CV) showed a relative proportion increasing to approximately 50%. At this stage, the proportion of the tannin vacuole, occurring in the vicinity of the nucleus, decreased to approximately 10%. The presence of the condensed type of tannins (proanthocyanidins) was proven by detecting their fluorescence under UV light and by specific chemical staining. This dual vacuolar profile was also observed in nonmotile parts of M. pudica (e.g., the petiole and the stem). Additional observations of leaflet pulvini showing more or less rapid movements showed that this double vacuolar structure was present in certain plants (Mimosa spegazzinii and Desmodium gyrans), but absent in others (Albizzia julibrissin, Biophytum sensitivum, and Cassia fasciculata). Taken together, these observations strongly suggest that a direct correlation cannot be found between the presence of a tannin vacuole and the osmoregulated motility of pulvini.
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Affiliation(s)
- Pierrette Fleurat-Lessard
- Laboratoire EBI (Ecologie et Biologie des Interactions), UMR CNRS 7267, Equipe SÈVE (Sucres & Échanges Végétaux- Environnement), Université de Poitiers, Bât. B 31, 3 rue Jacques Fort, TSA 51106, 86073, Poitiers Cedex 9, France
| | - Emile Béré
- Image UP, Service de Microscopie Electronique et Photonique, Pôle Biologie Santé, Université de Poitiers, 1 rue Georges Bonnet, TSA 51106, Poitiers Cedex 9, France
| | - Magali Lallemand
- Laboratoire EBI (Ecologie et Biologie des Interactions), UMR CNRS 7267, Equipe SÈVE (Sucres & Échanges Végétaux- Environnement), Université de Poitiers, Bât. B 31, 3 rue Jacques Fort, TSA 51106, 86073, Poitiers Cedex 9, France
| | - Fabienne Dédaldéchamp
- Laboratoire EBI (Ecologie et Biologie des Interactions), UMR CNRS 7267, Equipe SÈVE (Sucres & Échanges Végétaux- Environnement), Université de Poitiers, Bât. B 31, 3 rue Jacques Fort, TSA 51106, 86073, Poitiers Cedex 9, France.
| | - Gabriel Roblin
- Laboratoire EBI (Ecologie et Biologie des Interactions), UMR CNRS 7267, Equipe SÈVE (Sucres & Échanges Végétaux- Environnement), Université de Poitiers, Bât. B 31, 3 rue Jacques Fort, TSA 51106, 86073, Poitiers Cedex 9, France
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20
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Pedrazzini E, Caprera A, Fojadelli I, Stella A, Rocchetti A, Bassin B, Martinoia E, Vitale A. The Arabidopsis tonoplast is almost devoid of glycoproteins with complex N-glycans, unlike the rat lysosomal membrane. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:1769-81. [PMID: 26748395 PMCID: PMC4783361 DOI: 10.1093/jxb/erv567] [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] [Indexed: 05/02/2023]
Abstract
The distribution of the N-glycoproteome in integral membrane proteins of the vacuolar membrane (tonoplast) or the plasma membrane of Arabidopsis thaliana and, for further comparison, of the Rattus norvegicus lysosomal and plasma membranes, was analyzed. In silico analysis showed that potential N-glycosylation sites are much less frequent in tonoplast proteins. Biochemical analysis of Arabidopsis subcellular fractions with the lectin concanavalin A, which recognizes mainly unmodified N-glycans, or with antiserum against Golgi-modified N-glycans confirmed the in silico results and showed that, unlike the plant plasma membrane, the tonoplast is almost or totally devoid of N-glycoproteins with Golgi-modified glycans. Lysosomes share with vacuoles the hydrolytic functions and the position along the secretory pathway; however, our results indicate that their membranes had a divergent evolution. We propose that protection against the luminal hydrolases that are abundant in inner hydrolytic compartments, which seems to have been achieved in many lysosomal membrane proteins by extensive N-glycosylation of the luminal domains, has instead been obtained in the vast majority of tonoplast proteins by limiting the length of such domains.
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Affiliation(s)
| | | | | | | | | | - Barbara Bassin
- Institute of Plant Biology, University of Zurich, Zurich, Switzerland
| | - Enrico Martinoia
- Institute of Plant Biology, University of Zurich, Zurich, Switzerland
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21
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New Insight into the Mechanism and Function of Autophagy in Plant Cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 320:1-40. [PMID: 26614870 DOI: 10.1016/bs.ircmb.2015.07.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Autophagy is a degradation pathway that is conserved throughout eukaryotic organisms and plays important roles in the tolerance of abiotic and biotic stresses. It functions as a housekeeping process to remove unwanted cell components under normal conditions, and is induced during stress and senescence to break down damaged cellular contents and to recycle materials. The target components are engulfed into specialized transport structures termed autophagosomes and are subsequently delivered to the vacuole for degradation. Here, we review milestones in the study of autophagy in plants, discuss recent advances in our understanding of the mechanism and physiological roles of plant autophagy, and highlight potential future directions of research.
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22
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Yang W, Cai J, Zhou Z, Zhou G, Mei F, Wang L. Microautophagy involves programmed cell semi-death of sieve elements in developing caryopsis of Triticum aestivum L. Cell Biol Int 2015; 39:1364-75. [PMID: 26146941 DOI: 10.1002/cbin.10512] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 07/02/2015] [Indexed: 11/10/2022]
Abstract
Differentiation of sieve elements (SEs) involves programmed cell semi-death, in which a small amount of organelles is retained. However, the mechanisms by which a large amount of SE cytoplasm is degraded and the specific proteases involved are not clear. In this study, we confirmed that the degradation of cytoplasm outside of the vacuole was mediated by microautophagy of the vacuole, and that the tonoplast selectively fused with the plasma membrane after most of the cytoplasm in the vacuoles was degraded. The integration of space enclosed a small amount of cytoplasm. Therefore, that fraction of the cytoplasm was preserved. At the same time, the cytosol was weakly acidic during membrane fusion because part of the tonoplast was ruptured. We also demonstrated that wheat aspartic protease (WAP1) and proteases including cathepsin B activity (PICA) were involved in programmed cell semi-death of SEs. PICA showed strongest activity before mass of the cytoplasm was degraded, which might contribute toward SE stability. We found that WAP1 mainly degraded the cytoplasm. Therefore, programmed cell semi-death of SEs might result from the joint action of vacuoles and multiple proteases.
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Affiliation(s)
- Wenli Yang
- Laboratory of Cell Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jingtong Cai
- Laboratory of Cell Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhuqing Zhou
- Laboratory of Cell Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Guangsheng Zhou
- College of Plant Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Fangzhu Mei
- College of Plant Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Likai Wang
- Laboratory of Cell Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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Gendre D, Jonsson K, Boutté Y, Bhalerao RP. Journey to the cell surface--the central role of the trans-Golgi network in plants. PROTOPLASMA 2015; 252:385-98. [PMID: 25187082 DOI: 10.1007/s00709-014-0693-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 08/21/2014] [Indexed: 05/11/2023]
Abstract
The secretion of proteins, lipids, and carbohydrates to the cell surface is essential for plant development and adaptation. Secreted substances synthesized at the endoplasmic reticulum pass through the Golgi apparatus and trans-Golgi network (TGN) en route to the plasma membrane via the conventional secretion pathway. The TGN is morphologically and functionally distinct from the Golgi apparatus. The TGN is located at the crossroads of many trafficking pathways and regulates a range of crucial processes including secretion to the cell surface, transport to the vacuole, and the reception of endocytic cargo. This review outlines the TGN's central role in cargo secretion, showing that its behavior is more complex and controlled than the bulk-flow hypothesis suggests. Its formation, structure, and maintenance are discussed along with the formation and release of secretory vesicles.
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Affiliation(s)
- Delphine Gendre
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden,
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25
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Bassham DC. Methods for analysis of autophagy in plants. Methods 2014; 75:181-8. [PMID: 25239736 DOI: 10.1016/j.ymeth.2014.09.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/06/2014] [Accepted: 09/08/2014] [Indexed: 12/19/2022] Open
Abstract
The plant vacuole is a major site for the breakdown and recycling of cellular macromolecules. Cytoplasmic components destined for degradation are delivered to the vacuole in vesicles termed autophagosomes, and the breakdown products are transported back into the cytosol for reuse, with the overall process termed autophagy. In plants, autophagy is required for nutrient remobilization and recycling during senescence and nutrient deficiency, for clearance of protein aggregates and damaged organelles during environmental stress, for pathogen defense, and for general cellular maintenance under normal growth conditions. There is growing interest in autophagy in plants due to the wide range of processes in which it functions. While much of the work thus far has used the model plant Arabidopsis thaliana, autophagy is now under investigation in a number of other plants, particularly in economically important crop species. Here, I discuss methods for assessing autophagy activity in plant cells. Microscopic and biochemical assays are described, along with ways to distinguish the steady-state number of autophagosomes from flux through the autophagic pathway. Some deficiencies still exist in plant autophagy analysis, and there is a particular need for more accurate methods of quantifying autophagic flux in plants.
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Affiliation(s)
- Diane C Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA; Plant Sciences Institute, Iowa State University, Ames, IA 50011, USA.
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Niki T, Saito S, Gladish DK. Granular bodies in root primary meristem cells of Zea mays L. var. Cuscoensis K. (Poaceae) that enter young vacuoles by invagination: a novel ribophagy mechanism. PROTOPLASMA 2014; 251:1141-9. [PMID: 24585069 DOI: 10.1007/s00709-014-0622-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 01/29/2014] [Indexed: 05/26/2023]
Abstract
Because it has a very large, very rapidly growing primary root, we evaluated giant maize (Zea mays var. Cuscoensis) as a model organism for root research. Granular inclusions are a common feature of cells in many organisms, but they are not common in root meristems. We here report the presence of granules in root tip cells of giant maize. Seeds were germinated at 20 °C in sterile conditions. Four to 5-day-old primary roots were fixed, embedded, and sectioned for light and electron microscopy. Granules (1-2 μm) were observed in small vacuoles in all cell types of the apical meristem zone and mainly in parenchyma cells of the procambium in the primary meristem zone. Some sections were treated with ribonuclease and/or proteinase and then stained with toluidine blue, methyl green pyronin, or Coomassie brilliant blue. The results were used to determine that the granules were composed primarily of RNA and protein. In electron micrographs, consistent with the enzyme experiment results, granules appeared to be dense aggregates of polyribosomes and rough endoplasmic reticulum. They formed first in the cytosol, then invaginated into an adjacent vacuole. The granules are apparently ephemeral and therefore may not have a function other than being subject to autolysis. We speculate that they are part of a previously undescribed ribophagy system that operates during rapid cell growth and differentiation to regulate translation and recycle granule components.
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Affiliation(s)
- Teruo Niki
- Department of Biotechnology, Takushoku University, Tatemachi 815-1, Hachioji, Tokyo, 193-0985, Japan
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27
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Papini A, Mosti S, van Doorn WG. Classical macroautophagy in Lobivia rauschii (Cactaceae) and possible plastidial autophagy in Tillandsia albida (Bromeliaceae) tapetum cells. PROTOPLASMA 2014; 251:719-725. [PMID: 24158376 DOI: 10.1007/s00709-013-0567-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 10/09/2013] [Indexed: 06/02/2023]
Abstract
The tapetum in anthers is a tissue that undergoes programmed cell death (PCD) during the production of pollen. We observed two types of autophagy prior to cell death. In Lobivia rauschii (Cactaceae), tapetum cells showed plant-type autophagosomes-autolysosomes, which have been found previously exclusively in root meristem cells. The autophagic structures were formed by a network of tubules which apparently merged laterally, thereby sequestering a portion of the cytoplasm. The organelles observed in the sequestered material included multilamellar bodies, which have not been reported earlier in these organelles. By contrast, Tillandsia albida (Bromeliaceae) tapetum cells contained no such organelles but showed plastids that might possibly carry out autophagy, as they contained portions of the cytoplasm similar to the phenomenon reported earlier in Phaseolus and Dendrobium. However, the ultrastructure of the T. albida plastids was different from that in the previous reports. It is concluded that in L. rauschii classical plant macroautophagy was involved in degradation of the cytoplasm, while in T. albida such classical macroautophagy was not observed. Instead, the data in T. albida suggested the hypothesis that plastids are able to carry out degradation of the cytoplasm.
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Affiliation(s)
- Alessio Papini
- Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy,
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Autophagy-related direct membrane import from ER/cytoplasm into the vacuole or apoplast: a hidden gateway also for secondary metabolites and phytohormones? Int J Mol Sci 2014; 15:7462-74. [PMID: 24786101 PMCID: PMC4057683 DOI: 10.3390/ijms15057462] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/18/2014] [Accepted: 03/18/2014] [Indexed: 02/06/2023] Open
Abstract
Transportation of low molecular weight cargoes into the plant vacuole represents an essential plant cell function. Several lines of evidence indicate that autophagy-related direct endoplasmic reticulum (ER) to vacuole (and also, apoplast) transport plays here a more general role than expected. This route is regulated by autophagy proteins, including recently discovered involvement of the exocyst subcomplex. Traffic from ER into the vacuole bypassing Golgi apparatus (GA) acts not only in stress-related cytoplasm recycling or detoxification, but also in developmentally-regulated biopolymer and secondary metabolite import into the vacuole (or apoplast), exemplified by storage proteins and anthocyanins. We propose that this pathway is relevant also for some phytohormones’ (e.g., auxin, abscisic acid (ABA) and salicylic acid (SA)) degradation. We hypothesize that SA is not only an autophagy inducer, but also a cargo for autophagy-related ER to vacuole membrane container delivery and catabolism. ER membrane localized enzymes will potentially enhance the area of biosynthetic reactive surfaces, and also, abundant ER localized membrane importers (e.g., ABC transporters) will internalize specific molecular species into the autophagosome biogenesis domain of ER. Such active ER domains may create tubular invaginations of tonoplast into the vacuoles as import intermediates. Packaging of cargos into the ER-derived autophagosome-like containers might be an important mechanism of vacuole and exosome biogenesis and cytoplasm protection against toxic metabolites. A new perspective on metabolic transformations intimately linked to membrane trafficking in plants is emerging.
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Viotti C. ER and vacuoles: never been closer. FRONTIERS IN PLANT SCIENCE 2014; 5:20. [PMID: 24550928 PMCID: PMC3913007 DOI: 10.3389/fpls.2014.00020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 01/17/2014] [Indexed: 05/02/2023]
Abstract
The endoplasmic reticulum (ER) represents the gateway for intracellular trafficking of membrane proteins, soluble cargoes and lipids. In all eukaryotes, the best described mechanism of exiting the ER is via COPII-coated vesicles, which transport both membrane proteins and soluble cargoes to the cis-Golgi. The vacuole, together with the plasma membrane, is the most distal point of the secretory pathway, and many vacuolar proteins are transported from the ER through intermediate compartments. However, past results and recent findings demonstrate the presence of alternative transport routes from the ER towards the tonoplast, which are independent of Golgi- and post-Golgi trafficking. Moreover, the transport mechanism of the vacuolar proton pumps VHA-a3 and AVP1 challenges the current model of vacuole biogenesis, pointing to the endoplasmic reticulum for being the main membrane source for the biogenesis of the plant lytic compartment. This review gives an overview of the current knowledge on the transport routes towards the vacuole and discusses the possible mechanism of vacuole biogenesis in plants.
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Affiliation(s)
- Corrado Viotti
- *Correspondence: Corrado Viotti, Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Linnéusväg 6, 90187 Umeå, Sweden e-mail:
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Feeney M, Frigerio L, Kohalmi SE, Cui Y, Menassa R. Reprogramming cells to study vacuolar development. FRONTIERS IN PLANT SCIENCE 2013; 4:493. [PMID: 24348496 PMCID: PMC3848493 DOI: 10.3389/fpls.2013.00493] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 11/15/2013] [Indexed: 05/29/2023]
Abstract
During vegetative and embryonic developmental transitions, plant cells are massively reorganized to support the activities that will take place during the subsequent developmental phase. Studying cellular and subcellular changes that occur during these short transitional periods can sometimes present challenges, especially when dealing with Arabidopsis thaliana embryo and seed tissues. As a complementary approach, cellular reprogramming can be used as a tool to study these cellular changes in another, more easily accessible, tissue type. To reprogram cells, genetic manipulation of particular regulatory factors that play critical roles in establishing or repressing the seed developmental program can be used to bring about a change of cell fate. During different developmental phases, vacuoles assume different functions and morphologies to respond to the changing needs of the cell. Lytic vacuoles (LVs) and protein storage vacuoles (PSVs) are the two main vacuole types found in flowering plants such as Arabidopsis. Although both are morphologically distinct and carry out unique functions, they also share some similar activities. As the co-existence of the two vacuole types is short-lived in plant cells, how they replace each other has been a long-standing curiosity. To study the LV to PSV transition, LEAFY COTYLEDON2, a key transcriptional regulator of seed development, was overexpressed in vegetative cells to activate the seed developmental program. At the cellular level, Arabidopsis leaf LVs were observed to convert to PSV-like organelles. This presents the opportunity for further research to elucidate the mechanism of LV to PSV transitions. Overall, this example demonstrates the potential usefulness of cellular reprogramming as a method to study cellular processes that occur during developmental transitions.
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Affiliation(s)
- Mistianne Feeney
- Department of Biology, University of Western OntarioLondon, ON, Canada
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food CanadaLondon, ON, Canada
- School of Life Sciences, University of WarwickCoventry, UK
| | | | | | - Yuhai Cui
- Department of Biology, University of Western OntarioLondon, ON, Canada
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food CanadaLondon, ON, Canada
| | - Rima Menassa
- Department of Biology, University of Western OntarioLondon, ON, Canada
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food CanadaLondon, ON, Canada
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Wanner G, Schäfer T, Lütz-Meindl U. 3-D analysis of dictyosomes and multivesicular bodies in the green alga Micrasterias denticulata by FIB/SEM tomography. J Struct Biol 2013; 184:203-11. [PMID: 24135121 PMCID: PMC3899002 DOI: 10.1016/j.jsb.2013.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 09/30/2013] [Accepted: 10/02/2013] [Indexed: 12/24/2022]
Abstract
In the present study we employ FIB/SEM tomography for analyzing 3-D architecture of dictyosomes and formation of multivesicular bodies (MVB) in high pressure frozen and cryo-substituted interphase cells of the green algal model system Micrasterias denticulata. The ability of FIB/SEM of milling very thin ‘slices’ (5–10 nm), viewing the block face and of capturing cytoplasmic volumes of several hundred μm3 provides new insight into the close spatial connection of the ER–Golgi machinery in an algal cell particularly in z-direction, complementary to informations obtained by TEM serial sectioning or electron tomography. Our FIB/SEM series and 3-D reconstructions show that interphase dictyosomes of Micrasterias are not only closely associated to an ER system at their cis-side which is common in various plant cells, but are surrounded by a huge “trans-ER” sheath leading to an almost complete enwrapping of dictyosomes by the ER. This is particularly interesting as the presence of a trans-dictyosomal ER system is well known from mammalian secretory cells but not from cells of higher plants to which the alga Micrasterias is closely related. In contrast to findings in plant storage tissue indicating that MVBs originate from the trans-Golgi network or its derivatives our investigations show that MVBs in Micrasterias are in direct spatial contact with both, trans-Golgi cisternae and the trans-ER sheath which provides evidence that both endomembrane compartments are involved in their formation.
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Affiliation(s)
- Gerhard Wanner
- Ultrastructural Research, Faculty of Biology, Ludwig-Maximilians-University, Munich, Großhadernerstr. 2-4, D-82152 Planegg-Martinsried, Germany.
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32
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Viotti C, Krüger F, Krebs M, Neubert C, Fink F, Lupanga U, Scheuring D, Boutté Y, Frescatada-Rosa M, Wolfenstetter S, Sauer N, Hillmer S, Grebe M, Schumacher K. The endoplasmic reticulum is the main membrane source for biogenesis of the lytic vacuole in Arabidopsis. THE PLANT CELL 2013; 25:3434-49. [PMID: 24014545 PMCID: PMC3809542 DOI: 10.1105/tpc.113.114827] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/13/2013] [Accepted: 08/21/2013] [Indexed: 05/18/2023]
Abstract
Vacuoles are multifunctional organelles essential for the sessile lifestyle of plants. Despite their central functions in cell growth, storage, and detoxification, knowledge about mechanisms underlying their biogenesis and associated protein trafficking pathways remains limited. Here, we show that in meristematic cells of the Arabidopsis thaliana root, biogenesis of vacuoles as well as the trafficking of sterols and of two major tonoplast proteins, the vacuolar H(+)-pyrophosphatase and the vacuolar H(+)-adenosinetriphosphatase, occurs independently of endoplasmic reticulum (ER)-Golgi and post-Golgi trafficking. Instead, both pumps are found in provacuoles that structurally resemble autophagosomes but are not formed by the core autophagy machinery. Taken together, our results suggest that vacuole biogenesis and trafficking of tonoplast proteins and lipids can occur directly from the ER independent of Golgi function.
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Affiliation(s)
- Corrado Viotti
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, 69120 Heidelberg, Germany
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, 90187 Umea, Sweden
| | - Falco Krüger
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Melanie Krebs
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Christoph Neubert
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Fabian Fink
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Upendo Lupanga
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, 69120 Heidelberg, Germany
| | - David Scheuring
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Yohann Boutté
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, 90187 Umea, Sweden
| | - Márcia Frescatada-Rosa
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, 90187 Umea, Sweden
| | - Susanne Wolfenstetter
- Molecular Plant Physiology, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Norbert Sauer
- Molecular Plant Physiology, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Stefan Hillmer
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Markus Grebe
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, 90187 Umea, Sweden
| | - Karin Schumacher
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, 69120 Heidelberg, Germany
- Address correspondence to
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van Doorn WG, Kirasak K, Ketsa S. Amorphous areas in the cytoplasm of Dendrobium tepal cells: production through organelle degradation and destruction through macroautophagy? Autophagy 2013; 9:1159-66. [PMID: 23823702 DOI: 10.4161/auto.24784] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In Dendrobium flowers some tepal mesophyll cells showed cytoplasmic areas devoid of large organelles. Such amorphous areas comprised up to about 40% of the cross-section of a cell. The areas were not bound by a membrane. The origin of these areas is not known. We show data suggesting that they can be formed from vesicle-like organelles. The data imply that these organelles and other material become degraded inside the cytoplasm. This can be regarded as a form of autophagy. The amorphous areas became surrounded by small vacuoles, vesicles or double membranes. These seemed to merge and thereby sequester the areas. Degradation of the amorphous areas therefore seemed to involve macroautophagy.
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Affiliation(s)
- Wouter G van Doorn
- Mann Laboratory; Department of Plant Sciences; University of California, Davis; Davis, CA USA
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Yoshimoto K. Beginning to understand autophagy, an intracellular self-degradation system in plants. PLANT & CELL PHYSIOLOGY 2012; 53:1355-65. [PMID: 22764279 DOI: 10.1093/pcp/pcs099] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Autophagy is an evolutionarily conserved intracellular process for the vacuolar degradation of cytoplasmic components. There is no doubt that autophagy is very important to plant life, especially because plants are immobile and must survive in environmental extremes. Early studies of autophagy provided our first insights into the structural characteristics of the process in plants, but for a long time the molecular mechanisms and the physiological roles of autophagy were not understood. Genetic analyses of autophagy in the yeast Saccharomyces cerevisiae have greatly expanded our knowledge of the molecular aspects of autophagy in plants as well as in animals. Until recently our knowledge of plant autophagy was in its infancy compared with autophagy research in yeast and animals, but recent efforts by plant researchers have made many advances in our understanding of plant autophagy. Here I will introduce an overview of autophagy in plants, present current findings and discuss the physiological roles of self-degradation.
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Affiliation(s)
- Kohki Yoshimoto
- INRA, UMR1318, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France.
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35
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Abstract
Plants have developed sophisticated mechanisms to survive when in unfavorable environments. Autophagy is a macromolecule degradation pathway that recycles damaged or unwanted cell materials upon encountering stress conditions or during specific developmental processes. Over the past decade, our molecular and physiological understanding of plant autophagy has greatly increased. Most of the essential machinery required for autophagy seems to be conserved from yeast to plants. Plant autophagy has been shown to function in various stress responses, pathogen defense, and senescence. Some of its potential upstream regulators have also been identified. Here, we describe recent advances in our understanding of autophagy in plants, discuss areas of controversy, and highlight potential future directions in autophagy research.
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Affiliation(s)
- Yimo Liu
- Department of Genetics, Development, and Cell Biology and Interdepartmental Genetics Program, Iowa State University, Ames, IA 50011, USA
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36
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Oh-ye Y, Inoue Y, Moriyasu Y. Detecting autophagy in Arabidopsis roots by membrane-permeable cysteine protease inhibitor E-64d and endocytosis tracer FM4-64. PLANT SIGNALING & BEHAVIOR 2011; 6:1946-9. [PMID: 22105025 PMCID: PMC3337184 DOI: 10.4161/psb.6.12.18297] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Autophagy is the process by which cells degrade their own components in lysosomes or vacuoles. Autophagy in tobacco BY-2 cells cultured in sucrose-free medium takes place in formed, autolysosomes in the presence of a cysteine protease inhibitor. The autolysosomes in BY-2 cells are located in the endocytotic pathway and thus can be stained with fluorescent endocytosis marker FM4-64. In the present study, in order to detect autophagy in the root cells of Arabidopsis, we incubated root tips from Arabidopsis seedlings in culture medium containing the membrane-permeable cysteine protease inhibitor E-64d and FM4-64, and examined whether autolysosomes stained with FM4-64 are accumulated. The results suggest that autophagy accompanying the formation of autolysosomes also occurs in Arabidopsis root cells. Such autophagy appeared to occur constitutively in the root cells in nutrient-sufficient culture medium. Even in atg5 mutants in which an autophagy-related gene is disrupted, accumulation of the structures stained with FM4-64, which likely correspond to autolysosomes, was seen although at lower level than in wild type roots.
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Affiliation(s)
- Yuumi Oh-ye
- Graduate School of Science and Engineering; Saitama University; Saitama Japan
| | - Yuko Inoue
- Graduate School of Food and Nutritional Sciences; University of Shizuoka; Shizuoka, Japan
| | - Yuji Moriyasu
- Graduate School of Science and Engineering; Saitama University; Saitama Japan
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37
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Takatsuka C, Inoue Y, Higuchi T, Hillmer S, Robinson DG, Moriyasu Y. Autophagy in tobacco BY-2 cells cultured under sucrose starvation conditions: isolation of the autolysosome and its characterization. PLANT & CELL PHYSIOLOGY 2011; 52:2074-87. [PMID: 22039105 DOI: 10.1093/pcp/pcr137] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Tobacco culture cells carry out a large-scale degradation of intracellular proteins in order to survive under sucrose starvation conditions. We have previously suggested that this bulk degradation of cellular proteins is performed by autophagy, where autolysosomes formed de novo act as the major lytic compartments. The digestion process in autolysosomes can be retarded by addition of the cysteine protease inhibitor E-64c to the culture medium, resulting in the accumulation of autolysosomes. In the present study, we have investigated several properties of autolysosomes in tobacco cells. Electron microscopy showed that the autolysosomes contain osmiophilic particles, some of which resemble partially degraded mitochondria. It also revealed the presence of two kinds of autolysosome precursor structures; one resembled the isolation membrane and the other the autophagosome of mammalian cells. Immunofluorescence microscopy showed that autolysosomes contain acid phosphatase, in accordance with cytochemical enzyme analyses by light and electron microscopy in a previous study. Autolysosomes isolated by cell fractionation on Percoll gradients showed the localization of acid phosphatase, vacuolar H(+)-ATPase and cysteine protease. These results show that starvation-induced autophagy in tobacco cells follows a macroautophagic-type response similar to that described for other eukaryotes. However, our results indicate that, although the plant vacuole is often described as being equivalent to the lysosome of the animal cell, a new low pH lytic compartment-the autolysosome-also contributes to proteolytic degradation when tobacco cells are subjected to sucrose deprivation.
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Affiliation(s)
- Chihiro Takatsuka
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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38
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van Doorn WG. Classes of programmed cell death in plants, compared to those in animals. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:4749-61. [PMID: 21778180 DOI: 10.1093/jxb/err196] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Relatively little is known about programmed cell death (PCD) in plants. It is nonetheless suggested here that tonoplast rupture and the subsequent rapid destruction of the cytoplasm can distinguish two large PCD classes. One class, which is here called 'autolytic', shows this feature, whilst the second class (called 'non-autolytic') can include tonoplast rupture but does not show the rapid cytoplasm clearance. Examples of the 'autolytic' PCD class mainly occur during normal plant development and after mild abiotic stress. The 'non-autolytic' PCD class is mainly found during PCD that is due to plant-pathogen interactions. Three categories of PCD are currently recognized in animals: apoptosis, autophagy, and necrosis. An attempt is made to reconcile the recognized plant PCD classes with these groups. Apoptosis is apparently absent in plants. Autophagic PCD in animals is defined as being accompanied by an increase in the number of autophagosomes, autolysosomes, and small lytic vacuoles produced by autolysosomes. When very strictly adhering to this definition, there is no (proof for) autophagic PCD in plants. Upon a slightly more lenient definition, however, the 'autolytic' class of plant PCD can be merged with the autophagic PCD type in animal cells. The 'non-autolytic' class of plant PCD, as defined here, can be merged with necrotic PCD in animals.
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Affiliation(s)
- Wouter G van Doorn
- Mann Laboratory, Department of Plant Sciences, University of California, Davis, CA 95616, USA.
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Zheng H, Staehelin LA. Protein storage vacuoles are transformed into lytic vacuoles in root meristematic cells of germinating seedlings by multiple, cell type-specific mechanisms. PLANT PHYSIOLOGY 2011; 155:2023-35. [PMID: 21278307 PMCID: PMC3091105 DOI: 10.1104/pp.110.170159] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 01/24/2011] [Indexed: 05/18/2023]
Abstract
We have investigated the structural events associated with vacuole biogenesis in root tip cells of tobacco (Nicotiana tabacum) seedlings preserved by high-pressure freezing and freeze-substitution techniques. Our micrographs demonstrate that the lytic vacuoles (LVs) of root tip cells are derived from protein storage vacuoles (PSVs) by cell type-specific sets of transformation events. Analysis of the vacuole transformation pathways has been aided by the phytin-dependent black osmium staining of PSV luminal contents. In epidermal and outer cortex cells, the central LVs are formed by a process involving PSV fusion, storage protein degradation, and the gradual replacement of the PSV marker protein α-tonoplast intrinsic protein (TIP) with the LV marker protein γ-TIP. In contrast, in the inner cortex and vascular cylinder cells, the transformation events are more complex. During mobilization of the stored molecules, the PSV membranes collapse osmotically upon themselves, thereby squeezing the vacuolar contents into the remaining bulging vacuolar regions. The collapsed PSV membranes then differentiate into two domains: (1) vacuole "reinflation" domains that produce pre-LVs, and (2) multilamellar autophagosomal domains that are later engulfed by the pre-LVs. The multilamellar autophagosomal domains appear to originate from concentric sheets of PSV membranes that create compartments within which the cytoplasm begins to break down. Engulfment of the multilamellar autophagic vacuoles by the pre-LVs gives rise to the mature LVs. During pre-LV formation, the PSV marker α-TIP disappears and is replaced by the LV marker γ-TIP. These findings demonstrate that the central LVs of root cells arise from PSVs via cell type-specific transformation pathways.
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Affiliation(s)
- Huiqiong Zheng
- Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.
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van Doorn WG, Yoshimoto K. Role of chloroplasts and other plastids in ageing and death of plants and animals: a tale of Vishnu and Shiva. Ageing Res Rev 2010; 9:117-30. [PMID: 19720162 DOI: 10.1016/j.arr.2009.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2009] [Revised: 08/25/2009] [Accepted: 08/25/2009] [Indexed: 12/11/2022]
Abstract
Chloroplasts (chlorophyll-containing plastids) and other plastids are found in all plants and many animals. They are crucial to the survival of plants and most of the animals that harbour them. An example of a non-photosynthesizing plastid in animals is the apicoplast in the malaria-causing Plasmodium species, which is required for survival of the parasite. Many animals (such as sea slugs, sponges, reef corals, and clams) consume prey containing chloroplasts, or feed on algae. Some of these incorporate the chloroplasts from their food, or whole algal cells, into their own cells. Other species from these groups place algal cells between their own cells. Reef-building corals often lose their intracellular algae as a result of environmental changes, resulting in coral bleaching and death. The sensitivity of the chloroplast internal membranes to temperature stress is one of the reasons for coral death. Chloroplasts can also be a causal factor in the processes leading to whole-plant death, as the knockout of a gene encoding a chloroplast protein delayed the yellowing that proceeds death in tobacco plants. It is concluded that chloroplasts and other plastids are essential to individual survival in many species, including animals, and that they also play a role in triggering death in some plant and animal species.
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Autophagy in plants and phytopathogens. FEBS Lett 2010; 584:1350-8. [PMID: 20079356 DOI: 10.1016/j.febslet.2010.01.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 12/24/2009] [Accepted: 01/06/2010] [Indexed: 12/28/2022]
Abstract
Plants and plant-associated microorganisms including phytopathogens have to adapt to drastic changes in environmental conditions. Because of their immobility, plants must cope with various types of environmental stresses such as starvation, oxidative stress, drought stress, and invasion by phytopathogens during their differentiation, development, and aging processes. Here we briefly describe the early studies of plant autophagy, summarize recent studies on the molecular functions of ATG genes, and speculate on the role of autophagy in plants and phytopathogens. Autophagy regulates senescence and pathogen-induced cell death in plants, and autophagy and pexophagy play critical roles in differentiation and the invasion of host cells by phytopathogenic fungi.
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Cai X, Li W, Yin L. Ultrastructure and cytochemical localization of acid phosphatase of laticifers in Euphorbia kansui Liou. PROTOPLASMA 2009; 238:3-10. [PMID: 19649693 DOI: 10.1007/s00709-009-0065-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 07/13/2009] [Indexed: 05/23/2023]
Abstract
Acid phosphatase (AcPase) activities are involved in the degeneration process of cytoplasm in plants. In this study, acid phosphatase was detected by the method of lead nitrate and cytochemical electron microscopy during the development of nonarticulated laticifers in Euphorbia kansui Liou. The most important feature in the differentiation of the laticifers in E. kansui is that the development of small vacuoles arises from endoplasmic reticulum (ER). The mature laticifers possess a thin layer of electron-dense peripheral cytoplasm in which the organelle cannot be distinguished and a large central vacuole filled with latex particles. AcPase cytochemistry studies show AcPase reaction products congregated into heaps are distributed along the tonoplast of central vacuole and around the mitochondria and plastids. Some small vacuoles which develop at later developmental stages of laticifers contain AcPase reaction products. As a result, the central vacuole is formed by cellular autophagy and fusion of small vacuoles which apparently arises from ER.
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Affiliation(s)
- Xia Cai
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 710069, China.
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Wiltshire EJ, Collings DA. New Dynamics in an Old Friend: Dynamic Tubular Vacuoles Radiate Through the Cortical Cytoplasm of Red Onion Epidermal Cells. ACTA ACUST UNITED AC 2009; 50:1826-39. [DOI: 10.1093/pcp/pcp124] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Mitou G, Budak H, Gozuacik D. Techniques to study autophagy in plants. INTERNATIONAL JOURNAL OF PLANT GENOMICS 2009; 2009:451357. [PMID: 19730746 PMCID: PMC2734941 DOI: 10.1155/2009/451357] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2008] [Revised: 05/15/2009] [Accepted: 06/18/2009] [Indexed: 05/08/2023]
Abstract
Autophagy (or self eating), a cellular recycling mechanism, became the center of interest and subject of intensive research in recent years. Development of new molecular techniques allowed the study of this biological phenomenon in various model organisms ranging from yeast to plants and mammals. Accumulating data provide evidence that autophagy is involved in a spectrum of biological mechanisms including plant growth, development, response to stress, and defense against pathogens. In this review, we briefly summarize general and plant-related autophagy studies, and explain techniques commonly used to study autophagy. We also try to extrapolate how autophagy techniques used in other organisms may be adapted to plant studies.
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Affiliation(s)
- Géraldine Mitou
- Biological Science and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, Tuzla 34956, Istanbul, Turkey
| | - Hikmet Budak
- Biological Science and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, Tuzla 34956, Istanbul, Turkey
| | - Devrim Gozuacik
- Biological Science and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, Tuzla 34956, Istanbul, Turkey
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Chapter 3. New insights into plant vacuolar structure and dynamics. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 277:103-35. [PMID: 19766968 DOI: 10.1016/s1937-6448(09)77003-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The plant vacuole is a multifunctional organelle and is essential for plant development and growth. The most distinctive feature of the plant vacuole is its size, which usually occupies over 80-90% of the cell volume in well-developed somatic cells, and is therefore highly involved in cell growth and plant body size. Recent progress in the visualization of the vacuole, together with developments in image analysis, has revealed the highly organized and complex morphology of the vacuole, as well as its dynamics. The plant vacuolar membrane (VM) forms not only a typically large vacuole but also other structures, such as tubular structures, transvacuolar strands, bulbs, and sheets. In higher plant cells, actin microfilaments are mainly located near the VM and are involved in vacuolar shape changes with the actin-myosin systems. Most recently, microtubule-dependent regulation of vacuolar structures in moss plant cells was reported, suggesting a diversity of mechanisms regulating vacuolar morphogenesis.
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Vassalli JD, Granelli-Piperno A, Reich E. Neutral proteinases of leucocytes and the inflammatory process. CIBA FOUNDATION SYMPOSIUM 2008:381-95. [PMID: 399897 DOI: 10.1002/9780470720585.ch21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Plasminogen, the inactive precursor of plasmin, a general trypsin-like proteinase, is present at high concentration in blood and in body fluids. Most cells can recruit this proteolytic potential by secreting plasminogen activator (PA) to generate localized proteolysis in the surrounding microenvironment. PA and plasmin are serine enzymes whose pH optima match extracellular pH; further, in view of the large amount of circulating proenzyme and the broad substrate range of plasmin, the possibility that this proteolytic system can initiate a variety of proteolytic reactions or sequences should be kept in mind. PA production is precisely regulated by hormones, temporal programming, or both; and enzyme synthesis is correlated with some physiological and pathological processes requiring proteolysis. Thus PA production is coordinately regulated with ovulation, trophoblast implantation, spermatogenesis, polypeptide hormone synthesis, and some developmental phenomena; and with inflammation, tumour promotion, and neoplasia. Tissue remodelling and cell migration are common to many of these processes. Macrophage (monocyte) and polymorphonuclear leucocyte PA production is modulated by many biologically active substances. Enzyme synthesis is induced and stimulated by stimuli that recruit these cells to sites of inflammation, and it is repressed by anti-inflammatory agents, notably by glucocorticoids.
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Mortimore GE, Schworer CM. Application of liver perfusion as an in vitro model in studies of intracellular protein degradation. CIBA FOUNDATION SYMPOSIUM 2008:281-305. [PMID: 399892 DOI: 10.1002/9780470720585.ch17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Amino acids appear to be prime regulators of autophagy and proteolysis in liver. They both attain a maximum rapidly when livers from fed rats are perfused in the single-pass mode without amino acids and are suppressed to basal levels by amino acid additions. The fact that their greatest responsiveness to amino acids occurs slightly below normal plasma levels suggests that these cellular processes could play a role in regulating plasma amino acid concentrations in vivo. Autophagy and proteolysis are also inhibited by insulin and stimulated by glucagon. In the latter instance the hormonal action is not direct but mediated indirectly by depletion of intracellular glutamine, probably as a consequence of enhanced gluconeogenesis. Close correlations among (1) rates of intracellular proteolysis, (2) the aggregate volume of lysosomal elements, and (3) estimates of degradable protein internalized within lysosomes indicate that lysosomal function can explain total intracellular protein degradation (with the possible exception of rapidly turning over fractions) over the full range of proteolysis from maximum down to and including the basal state. Since ratios of degradable intralysosomal protein to corresponding rates of proteolysis in intact liver are constant over this range, protein internalization may be the rate-limiting step in lysosomal proteolysis.
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Poustka F, Irani NG, Feller A, Lu Y, Pourcel L, Frame K, Grotewold E. A trafficking pathway for anthocyanins overlaps with the endoplasmic reticulum-to-vacuole protein-sorting route in Arabidopsis and contributes to the formation of vacuolar inclusions. PLANT PHYSIOLOGY 2007; 145:1323-35. [PMID: 17921343 PMCID: PMC2151709 DOI: 10.1104/pp.107.105064] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 09/24/2007] [Indexed: 05/18/2023]
Abstract
Plants produce a very large number of specialized compounds that must be transported from their site of synthesis to the sites of storage or disposal. Anthocyanin accumulation has provided a powerful system to elucidate the molecular and cellular mechanisms associated with the intracellular trafficking of phytochemicals. Benefiting from the unique fluorescent properties of anthocyanins, we show here that in Arabidopsis (Arabidopsis thaliana), one route for anthocyanin transport to the vacuole involves vesicle-like structures shared with components of the secretory pathway. By colocalizing the red fluorescence of the anthocyanins with green fluorescent protein markers of the endomembrane system in Arabidopsis seedlings, we show that anthocyanins are also sequestered to the endoplasmic reticulum and to endoplasmic reticulum-derived vesicle-like structures targeted directly to the protein storage vacuole in a Golgi-independent manner. Moreover, our results indicate that vacuolar accumulation of anthocyanins does not depend solely on glutathione S-transferase activity or ATP-dependent transport mechanisms. Indeed, we observed a dramatic increase of anthocyanin-filled subvacuolar structures, without a significant effect on total anthocyanin levels, when we inhibited glutathione S-transferase activity, or the ATP-dependent transporters with vanadate, a general ATPase inhibitor. Taken together, these results provide evidence for an alternative novel mechanism of vesicular transport and vacuolar sequestration of anthocyanins in Arabidopsis.
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Affiliation(s)
- Frantisek Poustka
- Department of Plant Cellular and Molecular Biology and Plant Biotechnology Center, Ohio State University, Columbus, Ohio 43210, USA
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Bassham DC. Plant autophagy--more than a starvation response. CURRENT OPINION IN PLANT BIOLOGY 2007; 10:587-93. [PMID: 17702643 DOI: 10.1016/j.pbi.2007.06.006] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Accepted: 06/07/2007] [Indexed: 05/16/2023]
Abstract
Autophagy is a conserved mechanism for the degradation of cellular contents in order to recycle nutrients or break down damaged or toxic material. This occurs by the uptake of cytoplasmic constituents into the vacuole, where they are degraded by vacuolar hydrolases. In plants, autophagy has been known for some time to be important for nutrient remobilization during sugar and nitrogen starvation and leaf senescence, but recent research has uncovered additional crucial roles for plant autophagy. These roles include the degradation of oxidized proteins during oxidative stress, disposal of protein aggregates, and possibly even removal of damaged proteins and organelles during normal growth conditions as a housekeeping function. A surprising regulatory function for autophagy in programmed cell death during the hypersensitive response to pathogen infection has also been identified.
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Affiliation(s)
- Diane C Bassham
- Department of Genetics, Development and Cell Biology, 253 Bessey Hall, Iowa State University, Ames, IA 50011, USA.
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Makarenko SP, Konenkina TA, Dudareva LV. Fatty acids of plant vacuolar membrane lipids. BIOCHEMISTRY (MOSCOW) SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2007. [DOI: 10.1134/s1990747807030051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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