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Chiu CY, Lung HF, Chou WC, Lin LY, Chow HX, Kuo YH, Chien PS, Chiou TJ, Liu TY. Autophagy-Mediated Phosphate Homeostasis in Arabidopsis Involves Modulation of Phosphate Transporters. PLANT & CELL PHYSIOLOGY 2023; 64:519-535. [PMID: 36943363 DOI: 10.1093/pcp/pcad015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 01/31/2023] [Accepted: 03/01/2023] [Indexed: 05/17/2023]
Abstract
Autophagy in plants is regulated by diverse signaling cascades in response to environmental changes. Fine-tuning of its activity is critical for the maintenance of cellular homeostasis under basal and stressed conditions. In this study, we compared the Arabidopsis autophagy-related (ATG) system transcriptionally under inorganic phosphate (Pi) deficiency versus nitrogen deficiency and showed that most ATG genes are only moderately upregulated by Pi starvation, with relatively stronger induction of AtATG8f and AtATG8h among the AtATG8 family. We found that Pi shortage increased the formation of GFP-ATG8f-labeled autophagic structures and the autophagic flux in the differential zone of the Arabidopsis root. However, the proteolytic cleavage of GFP-ATG8f and the vacuolar degradation of endogenous ATG8 proteins indicated that Pi limitation does not drastically alter the autophagic flux in the whole roots, implying a cell type-dependent regulation of autophagic activities. At the organismal level, the Arabidopsis atg mutants exhibited decreased shoot Pi concentrations and smaller meristem sizes under Pi sufficiency. Under Pi limitation, these mutants showed enhanced Pi uptake and impaired root cell division and expansion. Despite a reduced steady-state level of several PHOSPHATE TRANSPORTER 1s (PHT1s) in the atg root, cycloheximide treatment analysis suggested that the protein stability of PHT1;1/2/3 is comparable in the Pi-replete wild type and atg5-1. By contrast, the degradation of PHT1;1/2/3 is enhanced in the Pi-deplete atg5-1. Our findings reveal that both basal autophagy and Pi starvation-induced autophagy are required for the maintenance of Pi homeostasis and may modulate the expression of PHT1s through different mechanisms.
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Affiliation(s)
- Chang-Yi Chiu
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Hui-Fang Lung
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Wen-Chun Chou
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Li-Yen Lin
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Hong-Xuan Chow
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Yu-Hao Kuo
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Pei-Shan Chien
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11529, Taiwan
| | - Tzyy-Jen Chiou
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11529, Taiwan
| | - Tzu-Yin Liu
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
- Department of Life Science, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
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2
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Wojciechowska N, Michalak KM, Bagniewska-Zadworna A. Autophagy-an underestimated coordinator of construction and destruction during plant root ontogeny. PLANTA 2021; 254:15. [PMID: 34184131 PMCID: PMC8238727 DOI: 10.1007/s00425-021-03668-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 06/20/2021] [Indexed: 05/13/2023]
Abstract
MAIN CONCLUSION Autophagy is a key but undervalued process in root ontogeny, ensuring both the proper development of root tissues as well as the senescence of the entire organ. Autophagy is a process which occurs during plant adaptation to changing environmental conditions as well as during plant ontogeny. Autophagy is also engaged in plant root development, however, the limitations of belowground studies make it challenging to understand the entirety of the developmental processes. We summarize and discuss the current data pertaining to autophagy in the roots of higher plants during their formation and degradation, from the beginning of root tissue differentiation and maturation; all the way to the aging of the entire organ. During root growth, autophagy participates in the processes of central vacuole formation in cortical tissue development, as well as vascular tissue differentiation and root senescence. At present, several key issues are still not entirely understood and remain to be addressed in future studies. The major challenge lies in the portrayal of the mechanisms of autophagy on subcellular events in belowground plant organs during the programmed control of cellular degradation pathways in roots. Given the wide range of technical areas of inquiry where root-related research can be applied, including cutting-edge cell biological methods to track, sort and screen cells from different root tissues and zones of growth, the identification of several lines of evidence pertaining to autophagy during root developmental processes is the most urgent challenge. Consequently, a substantial effort must be made to ensure whether the analyzed process is autophagy-dependent or not.
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Affiliation(s)
- Natalia Wojciechowska
- Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland.
| | - Kornel M Michalak
- Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland
| | - Agnieszka Bagniewska-Zadworna
- Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland
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3
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Qin Y, Yang L, Sun Z, Wang X, Wang Y, Zhang J, Rehman AU, Chen Z, Qi J, Wang B, Song C, Yang S, Gong Z. Redox-Mediated Endocytosis of a Receptor-Like Kinase during Distal Stem Cell Differentiation Depends on Its Tumor Necrosis Factor Receptor Domain. PLANT PHYSIOLOGY 2019; 181:1075-1095. [PMID: 31471454 PMCID: PMC6836819 DOI: 10.1104/pp.19.00616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 08/20/2019] [Indexed: 05/05/2023]
Abstract
Cellular redox status plays critical roles in cell division and differentiation, but the underlying mechanism is unclear. Here we explored the effect of redox status on stem cell identity in distal stem cells (DSCs) of Arabidopsis (Arabidopsis thaliana) roots. Treatment with the reductive reagent glutathione and the oxidative reagent H2O2 inhibited DSC differentiation, as did endogenously altering reactive oxygen species production via various mutations. This suggests that both highly reductive and oxidative environments inhibit specification of stem cell identity. In our observations of mutant components of the CLAVATA3/ENDOSPERM SURROUNDING REGION 40 (CLE40)-ARABIDOPSIS CRINKLY4 (ACR4)/CLAVATA1 (CLV1)-WUSCHEL RELATED HOMEOBOX5 (WOX5) module, both reductive and oxidative reagents influenced DSC differentiation in wox5-1 and clv1-1, but not in acr4-2 or cle40 mutant plants. The stability of the receptor-like kinase ACR4 is modulated by redox status through endocytosis in root tips. ACR4 with multiple Cys mutations in the tumor necrosis factor receptor (TNFR) extracellular domain failed to undergo endocytosis. ACR4 with a complete deletion of the TNFR domain was localized directly to endosomes, bypassing the plasma membrane. Both mutations affected DSC differentiation, but not seed filling. Conversely, the intracellular domain of the ACR4 protein is partially required for seed filling, but not for DSC differentiation. Our study uncovers an important biological role of the TNFR domain in redox-mediated endocytosis of ACR4 in root DSC differentiation.
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Affiliation(s)
- Yingying Qin
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Li Yang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhihui Sun
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiangfeng Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yu Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jing Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Amin Ur Rehman
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhizhong Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Junsheng Qi
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Baoshan Wang
- Key Laboratory of Plant Stress Research, College of Life Science, Shandong Normal University, Ji'nan 250014, China
| | - Chunpeng Song
- Collaborative Innovation Center of Crop Stress Biology, Henan Province, Institute of Plant Stress Biology, Henan University, Kaifeng 475001, China
| | - Shuhua Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhizhong Gong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
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4
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Jiao Y, Srba M, Wang J, Chen W. Correlation of Autophagosome Formation with Degradation and Endocytosis Arabidopsis Regulator of G-Protein Signaling (RGS1) through ATG8a. Int J Mol Sci 2019; 20:ijms20174190. [PMID: 31461856 PMCID: PMC6747245 DOI: 10.3390/ijms20174190] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/20/2019] [Accepted: 08/26/2019] [Indexed: 12/30/2022] Open
Abstract
Damaged or unwanted cellular proteins are degraded by either autophagy or the ubiquitin/proteasome pathway. In Arabidopsis thaliana, sensing of D-glucose is achieved by the heterotrimeric G protein complex and regulator of G-protein signaling 1 (AtRGS1). Here, we showed that starvation increases proteasome-independent AtRGS1 degradation, and it is correlated with increased autophagic flux. RGS1 promoted the production of autophagosomes and autophagic flux; RGS1-yellow fluorescent protein (YFP) was surrounded by vacuolar dye FM4-64 (red fluorescence). RGS1 and autophagosomes co-localized in the root cells of Arabidopsis and BY-2 cells. We demonstrated that the autophagosome marker ATG8a interacts with AtRGS1 and its shorter form with truncation of the seven transmembrane and RGS1 domains in planta. Altogether, our data indicated the correlation of autophagosome formation with degradation and endocytosis of AtRGS1 through ATG8a.
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Affiliation(s)
- Yue Jiao
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China
- College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Miroslav Srba
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12844 Prague, Czech Republic
| | - Jingchun Wang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China
- College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Wenli Chen
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China.
- College of Biophotonics, South China Normal University, Guangzhou 510631, China.
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5
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Avin-Wittenberg T, Baluška F, Bozhkov PV, Elander PH, Fernie AR, Galili G, Hassan A, Hofius D, Isono E, Le Bars R, Masclaux-Daubresse C, Minina EA, Peled-Zehavi H, Coll NS, Sandalio LM, Satiat-Jeunemaitre B, Sirko A, Testillano PS, Batoko H. Autophagy-related approaches for improving nutrient use efficiency and crop yield protection. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1335-1353. [PMID: 29474677 DOI: 10.1093/jxb/ery069] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/16/2018] [Indexed: 05/18/2023]
Abstract
Autophagy is a eukaryotic catabolic pathway essential for growth and development. In plants, it is activated in response to environmental cues or developmental stimuli. However, in contrast to other eukaryotic systems, we know relatively little regarding the molecular players involved in autophagy and the regulation of this complex pathway. In the framework of the COST (European Cooperation in Science and Technology) action TRANSAUTOPHAGY (2016-2020), we decided to review our current knowledge of autophagy responses in higher plants, with emphasis on knowledge gaps. We also assess here the potential of translating the acquired knowledge to improve crop plant growth and development in a context of growing social and environmental challenges for agriculture in the near future.
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Affiliation(s)
- Tamar Avin-Wittenberg
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Frantisek Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Pernilla H Elander
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - Gad Galili
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot Israel
| | - Ammar Hassan
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Daniel Hofius
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, Uppsala, Sweden
| | - Erika Isono
- Department of Biology, University of Konstanz, Universitätsstrasse, Konstanz, Germany
| | - Romain Le Bars
- Cell Biology Pôle Imagerie-Gif, Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Céline Masclaux-Daubresse
- INRA-AgroParisTech, Institut Jean-Pierre Bourgin, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, Versailles, France
| | - Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Hadas Peled-Zehavi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot Israel
| | - Núria S Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra-Cerdanyola del Valles, Catalonia, Spain
| | - Luisa M Sandalio
- Departmento de Bioquímica, Biología Celular y Molecular de Plantas Experimental del Zaidín, CSIC, Granada, Spain
| | - Béatrice Satiat-Jeunemaitre
- Cell Biology Pôle Imagerie-Gif, Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Agnieszka Sirko
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, ul. Pawinskiego, Warsaw, Poland
| | - Pilar S Testillano
- Pollen Biotechnology of Crop Plants group, Centro de Investigaciones Biológicas, Biological Research Centre (CIB), CSIC, Ramiro de Maeztu, Madrid, Spain
| | - Henri Batoko
- Université Catholique de Louvain, Institute of Life Sciences, Croix du Sud, Louvain-la-Neuve, Belgium
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6
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Sanchez-Vera V, Kenchappa CS, Landberg K, Bressendorff S, Schwarzbach S, Martin T, Mundy J, Petersen M, Thelander M, Sundberg E. Autophagy is required for gamete differentiation in the moss Physcomitrella patens. Autophagy 2017; 13:1939-1951. [PMID: 28837383 PMCID: PMC5788497 DOI: 10.1080/15548627.2017.1366406] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 07/17/2017] [Accepted: 08/08/2017] [Indexed: 12/21/2022] Open
Abstract
Autophagy, a major catabolic process in eukaryotes, was initially related to cell tolerance to nutrient depletion. In plants autophagy has also been widely related to tolerance to biotic and abiotic stresses (through the induction or repression of programmed cell death, PCD) as well as to promotion of developmentally regulated PCD, starch degradation or caloric restriction important for life span. Much less is known regarding its role in plant cell differentiation. Here we show that macroautophagy, the autophagy pathway driven by engulfment of cytoplasmic components by autophagosomes and its subsequent degradation in vacuoles, is highly active during germ cell differentiation in the early diverging land plant Physcomitrella patens. Our data provide evidence that suppression of ATG5-mediated autophagy results in reduced density of the egg cell-mediated mucilage that surrounds the mature egg, pointing toward a potential role of autophagy in extracellular mucilage formation. In addition, we found that ATG5- and ATG7-mediated autophagy is essential for the differentiation and cytoplasmic reduction of the flagellated motile sperm and hence for sperm fertility. The similarities between the need of macroautophagy for sperm differentiation in moss and mouse are striking, strongly pointing toward an ancestral function of autophagy not only as a protector against nutrient stress, but also in gamete differentiation.
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Affiliation(s)
- Victoria Sanchez-Vera
- Department of Plant Biology, Swedish University of Agricultural Sciences, The Linnean Centre of Plant Biology in Uppsala, Uppsala, Sweden
| | - Chandra Shekar Kenchappa
- Department of Plant Biology, Swedish University of Agricultural Sciences, The Linnean Centre of Plant Biology in Uppsala, Uppsala, Sweden
| | - Katarina Landberg
- Department of Plant Biology, Swedish University of Agricultural Sciences, The Linnean Centre of Plant Biology in Uppsala, Uppsala, Sweden
| | | | - Stefan Schwarzbach
- Department of Plant Biology, Swedish University of Agricultural Sciences, The Linnean Centre of Plant Biology in Uppsala, Uppsala, Sweden
| | - Tom Martin
- Department of Plant Biology, Swedish University of Agricultural Sciences, The Linnean Centre of Plant Biology in Uppsala, Uppsala, Sweden
| | - John Mundy
- Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Morten Petersen
- Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Mattias Thelander
- Department of Plant Biology, Swedish University of Agricultural Sciences, The Linnean Centre of Plant Biology in Uppsala, Uppsala, Sweden
| | - Eva Sundberg
- Department of Plant Biology, Swedish University of Agricultural Sciences, The Linnean Centre of Plant Biology in Uppsala, Uppsala, Sweden
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7
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Fiume E, Guyon V, Remoué C, Magnani E, Miquel M, Grain D, Lepiniec L. TWS1, a Novel Small Protein, Regulates Various Aspects of Seed and Plant Development. PLANT PHYSIOLOGY 2016; 172:1732-1745. [PMID: 27613850 PMCID: PMC5100777 DOI: 10.1104/pp.16.00915] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/05/2016] [Indexed: 05/27/2023]
Abstract
Small proteins have long been overlooked due to their poor annotation and the experimental challenges they pose. However, in recent years, their role in various processes has started to emerge, opening new research avenues. Here, we present the isolation and characterization of two allelic mutants, twisted seed1-1 (tws1-1) and tws1-2, which exhibit an array of developmental and biochemical phenotypes in Arabidopsis (Arabidopsis thaliana) seeds. We have identified AT5G01075 as the subtending gene encoding a small protein of 81 amino acids localized in the endoplasmic reticulum. TWS1 is strongly expressed in seeds, where it regulates both embryo development and accumulation of storage compounds. TWS1 loss-of-function seeds exhibit increased starch, sucrose, and protein accumulation at the detriment of fatty acids. TWS1 is also expressed in vegetative and reproductive tissues, where it is responsible for proper epidermal cell morphology and overall plant growth. At the cellular level, TWS1 is responsible for cuticle deposition on epidermal cells and organization of the endomembrane system. Finally, we show that TWS1 is a single-copy gene in Arabidopsis, and it is specifically conserved among angiosperms.
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Affiliation(s)
- Elisa Fiume
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78026 Versailles Cedex, France (E.F., V.G., C.R., E.M., M.M., D.G., L.L.); Biogemma, Centre de Recherche de Chappes, 63720 Chappes, France (V.G.); and Génétique Quantitative et Évolution Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France (C.R.)
| | - Virginie Guyon
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78026 Versailles Cedex, France (E.F., V.G., C.R., E.M., M.M., D.G., L.L.); Biogemma, Centre de Recherche de Chappes, 63720 Chappes, France (V.G.); and Génétique Quantitative et Évolution Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France (C.R.)
| | - Carine Remoué
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78026 Versailles Cedex, France (E.F., V.G., C.R., E.M., M.M., D.G., L.L.); Biogemma, Centre de Recherche de Chappes, 63720 Chappes, France (V.G.); and Génétique Quantitative et Évolution Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France (C.R.)
| | - Enrico Magnani
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78026 Versailles Cedex, France (E.F., V.G., C.R., E.M., M.M., D.G., L.L.); Biogemma, Centre de Recherche de Chappes, 63720 Chappes, France (V.G.); and Génétique Quantitative et Évolution Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France (C.R.)
| | - Martine Miquel
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78026 Versailles Cedex, France (E.F., V.G., C.R., E.M., M.M., D.G., L.L.); Biogemma, Centre de Recherche de Chappes, 63720 Chappes, France (V.G.); and Génétique Quantitative et Évolution Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France (C.R.)
| | - Damaris Grain
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78026 Versailles Cedex, France (E.F., V.G., C.R., E.M., M.M., D.G., L.L.); Biogemma, Centre de Recherche de Chappes, 63720 Chappes, France (V.G.); and Génétique Quantitative et Évolution Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France (C.R.)
| | - Loïc Lepiniec
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78026 Versailles Cedex, France (E.F., V.G., C.R., E.M., M.M., D.G., L.L.); Biogemma, Centre de Recherche de Chappes, 63720 Chappes, France (V.G.); and Génétique Quantitative et Évolution Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France (C.R.)
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8
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Yokawa K, Baluška F. The TOR Complex: An Emergency Switch for Root Behavior. PLANT & CELL PHYSIOLOGY 2016; 57:14-8. [PMID: 26644459 DOI: 10.1093/pcp/pcv191] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/20/2015] [Indexed: 05/10/2023]
Abstract
Target of rapamycin (TOR) kinase is known to be a controller of cell growth and aging, which determines the fine balance between growth rates and energy availabilities. It has been reported that many eukaryotes express TOR genes. In plants, TOR signaling modifies growth and development in response to a plant's energy status. An example of TOR action can be found in the root apices, which are active organs that explore the soil environment via vigorous growth and numerous tropisms. The exploratory nature of root apices requires a large energy supply for signaling, as well as for cell division and elongation. In the case of negative tropisms, roots must respond quickly to avoid patches of unfavorable soil conditions, again by consuming precious energy reserves. Here we review the current findings on TOR signaling in plants and animals, and propose possible roles for this important complex in driving plant root negative tropisms, particularly during light escape and salt avoidance behavior.
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Affiliation(s)
- Ken Yokawa
- IZMB, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan
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9
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Cho SK, Ben Chaabane S, Shah P, Poulsen CP, Yang SW. COP1 E3 ligase protects HYL1 to retain microRNA biogenesis. Nat Commun 2014; 5:5867. [PMID: 25532508 DOI: 10.1038/ncomms6867] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 11/14/2014] [Indexed: 12/31/2022] Open
Abstract
Constitutive photomorphogenic 1 (COP1) is a RING-finger E3 ligase that plays a central role in photomorphogenesis by destabilizing many light-regulated transcription factors and photoreceptors. Here, we reveal a novel function for COP1 E3 ligase in controlling global miRNA biogenesis in Arabidopsis thaliana. In cop1 mutants, the level of miRNAs is dramatically reduced because of the diminution of HYPONASTIC LEAVES 1 (HYL1), an RNA-binding protein required for precise miRNA processing. HYL1 is destabilized by an unidentified protease, which we tentatively call protease X, that specifically cleaves the N-terminal region from HYL1, thus neutralizing its function. Our results further show that the cytoplasmic partitioning of COP1 under light is essential to protect HYL1 against protease X. Taken together, we suggest a novel regulatory network involving HYL1, protease X, COP1 and light signalling that is indispensable for miRNA biogenesis in Arabidopsis thaliana.
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Affiliation(s)
- Seok Keun Cho
- Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Samir Ben Chaabane
- Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Pratik Shah
- Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Christian Peter Poulsen
- Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Seong Wook Yang
- Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
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10
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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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Lv X, Pu X, Qin G, Zhu T, Lin H. The roles of autophagy in development and stress responses in Arabidopsis thaliana. Apoptosis 2014; 19:905-21. [DOI: 10.1007/s10495-014-0981-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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12
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Hanamata S, Kurusu T, Okada M, Suda A, Kawamura K, Tsukada E, Kuchitsu K. In vivo imaging and quantitative monitoring of autophagic flux in tobacco BY-2 cells. PLANT SIGNALING & BEHAVIOR 2013; 8:e22510. [PMID: 23123450 PMCID: PMC3745557 DOI: 10.4161/psb.22510] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/10/2012] [Accepted: 10/10/2012] [Indexed: 05/18/2023]
Abstract
Autophagy has been shown to play essential roles in the growth, development and survival of eukaryotic cells. However, simple methods for quantification and visualization of autophagic flux remain to be developed in living plant cells. Here, we analyzed the autophagic flux in transgenic tobacco BY-2 cell lines expressing fluorescence-tagged NtATG8a as a marker for autophagosome formation. Under sucrose-starved conditions, the number of punctate signals of YFP-NtATG8a increased, and the fluorescence intensity of the cytoplasm and nucleoplasm decreased. Conversely, these changes were not observed in BY-2 cells expressing a C-terminal glycine deletion mutant of the NtATG8a protein (NtATG8aΔG). To monitor the autophagic flux more easily, we generated a transgenic BY-2 cell line expressing NtATG8a fused to a pH-sensitive fluorescent tag, a tandem fusion of the acid-insensitive RFP and the acid-sensitive YFP. In sucrose-rich conditions, both fluorescent signals were detected in the cytoplasm and only weakly in the vacuole. In contrast, under sucrose-starved conditions, the fluorescence intensity of the cytoplasm decreased, and the RFP signal clearly increased in the vacuole, corresponding to the fusion of the autophagosome to the vacuole and translocation of ATG8 from the cytoplasm to the vacuole. Moreover, we introduce a novel simple easy way to monitor the autophagic flux non-invasively by only measuring the ratio of fluorescence of RFP and YFP in the cell suspension using a fluorescent image analyzer without microscopy. The present in vivo quantitative monitoring system for the autophagic flux offers a powerful tool for determining the physiological functions and molecular mechanisms of plant autophagy induced by environmental stimuli.
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Affiliation(s)
- Shigeru Hanamata
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Takamitsu Kurusu
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
- Research Institute for Science and Technology; Tokyo University of Science; Noda, Chiba, Japan
| | - Masaaki Okada
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Akiko Suda
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Koki Kawamura
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Emi Tsukada
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Kazuyuki Kuchitsu
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
- Research Institute for Science and Technology; Tokyo University of Science; Noda, Chiba, Japan
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