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Hickey K, Şahin Y, Turner G, Nazarov T, Jitkov V, Pumphrey M, Smertenko A. Genotype-Specific Activation of Autophagy during Heat Wave in Wheat. Cells 2024; 13:1226. [PMID: 39056807 PMCID: PMC11274669 DOI: 10.3390/cells13141226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 07/04/2024] [Accepted: 07/15/2024] [Indexed: 07/28/2024] Open
Abstract
Recycling of unnecessary or dysfunctional cellular structures through autophagy plays a critical role in cellular homeostasis and environmental resilience. Therefore, the autophagy trait may have been unintentionally selected in wheat breeding programs for higher yields in arid climates. This hypothesis was tested by measuring the response of three common autophagy markers, ATG7, ATG8, and NBR1, to a heat wave under reduced soil moisture content in 16 genetically diverse spring wheat landraces originating from different geographical locations. We observed in the greenhouse trials that ATG8 and NBR1 exhibited genotype-specific responses to a 1 h, 40 °C heat wave, while ATG7 did not show a consistent response. Three genotypes from Uruguay, Mozambique, and Afghanistan showed a pattern consistent with higher autophagic activity: decreased or stable abundance of both ATG8 and NBR1 proteins, coupled with increased transcription of ATG8 and NBR1. In contrast, three genotypes from Pakistan, Ethiopia, and Egypt exhibited elevated ATG8 protein levels alongside reduced or unaltered ATG8 transcript levels, indicating a potential suppression or no change in autophagic activity. Principal component analysis demonstrated a correlation between lower abundance of ATG8 and NBR1 proteins and higher yield in the field trials. We found that (i) the combination of heat and drought activated autophagy only in several genotypes, suggesting that despite being a resilience mechanism, autophagy is a heat-sensitive process; (ii) higher autophagic activity correlates positively with greater yield; (iii) the lack of autophagic activity in some high-yielding genotypes suggests contribution of alternative stress-resilient mechanisms; and (iv) enhanced autophagic activity in response to heat and drought was independently selected by wheat breeding programs in different geographic locations.
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Affiliation(s)
- Kathleen Hickey
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99163, USA (Y.Ş.); (G.T.); (T.N.)
| | - Yunus Şahin
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99163, USA (Y.Ş.); (G.T.); (T.N.)
| | - Glenn Turner
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99163, USA (Y.Ş.); (G.T.); (T.N.)
| | - Taras Nazarov
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99163, USA (Y.Ş.); (G.T.); (T.N.)
| | - Vadim Jitkov
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA 99163, USA; (V.J.); (M.P.)
| | - Mike Pumphrey
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA 99163, USA; (V.J.); (M.P.)
| | - Andrei Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99163, USA (Y.Ş.); (G.T.); (T.N.)
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Yagyu M, Yoshimoto K. New insights into plant autophagy: molecular mechanisms and roles in development and stress responses. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1234-1251. [PMID: 37978884 DOI: 10.1093/jxb/erad459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 11/17/2023] [Indexed: 11/19/2023]
Abstract
Autophagy is an evolutionarily conserved eukaryotic intracellular degradation process. Although the molecular mechanisms of plant autophagy share similarities with those in yeast and mammals, certain unique mechanisms have been identified. Recent studies have highlighted the importance of autophagy during vegetative growth stages as well as in plant-specific developmental processes, such as seed development, germination, flowering, and somatic reprogramming. Autophagy enables plants to adapt to and manage severe environmental conditions, such as nutrient starvation, high-intensity light stress, and heat stress, leading to intracellular remodeling and physiological changes in response to stress. In the past, plant autophagy research lagged behind similar studies in yeast and mammals; however, recent advances have greatly expanded our understanding of plant-specific autophagy mechanisms and functions. This review summarizes current knowledge and latest research findings on the mechanisms and roles of plant autophagy with the objective of improving our understanding of this vital process in plants.
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Affiliation(s)
- Mako Yagyu
- Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
- Life Sciences Program, Graduate School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Kohki Yoshimoto
- Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
- Life Sciences Program, Graduate School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
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3
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Hawkins TJ, Kopischke M, Duckney PJ, Rybak K, Mentlak DA, Kroon JTM, Bui MT, Richardson AC, Casey M, Alexander A, De Jaeger G, Kalde M, Moore I, Dagdas Y, Hussey PJ, Robatzek S. NET4 and RabG3 link actin to the tonoplast and facilitate cytoskeletal remodelling during stomatal immunity. Nat Commun 2023; 14:5848. [PMID: 37730720 PMCID: PMC10511709 DOI: 10.1038/s41467-023-41337-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 08/29/2023] [Indexed: 09/22/2023] Open
Abstract
Members of the NETWORKED (NET) family are involved in actin-membrane interactions. Here we show that two members of the NET family, NET4A and NET4B, are essential for normal guard cell actin reorganization, which is a process critical for stomatal closure in plant immunity. NET4 proteins interact with F-actin and with members of the Rab7 GTPase RABG3 family through two distinct domains, allowing for simultaneous localization to actin filaments and the tonoplast. NET4 proteins interact with GTP-bound, active RABG3 members, suggesting their function being downstream effectors. We also show that RABG3b is critical for stomatal closure induced by microbial patterns. Taken together, we conclude that the actin cytoskeletal remodelling during stomatal closure involves a molecular link between actin filaments and the tonoplast, which is mediated by the NET4-RABG3b interaction. We propose that stomatal closure to microbial patterns involves the coordinated action of immune-triggered osmotic changes and actin cytoskeletal remodelling likely driving compact vacuolar morphologies.
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Affiliation(s)
- Timothy J Hawkins
- Department of Biosciences, University of Durham, South Road, Durham, DH1 3LE, UK
| | - Michaela Kopischke
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
- LMU Munich Biocenter, Großhadener Strasse 4, 82152, Planegg, DE, Germany
| | - Patrick J Duckney
- Department of Biosciences, University of Durham, South Road, Durham, DH1 3LE, UK
| | - Katarzyna Rybak
- LMU Munich Biocenter, Großhadener Strasse 4, 82152, Planegg, DE, Germany
| | - David A Mentlak
- Department of Biosciences, University of Durham, South Road, Durham, DH1 3LE, UK
| | - Johan T M Kroon
- Department of Biosciences, University of Durham, South Road, Durham, DH1 3LE, UK
| | - Mai Thu Bui
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter, Vienna, AUT, Austria
| | | | - Mary Casey
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | | | - Geert De Jaeger
- VIB-University Ghent, Center for Plant System Biology, Technologiepark 927, 9052, Ghent, BE, Belgium
| | - Monika Kalde
- Department of Plant Sciences, University of Oxford, South Parks Rd., Oxford, OX1 3RB, UK
| | - Ian Moore
- Department of Plant Sciences, University of Oxford, South Parks Rd., Oxford, OX1 3RB, UK
| | - Yasin Dagdas
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter, Vienna, AUT, Austria
| | - Patrick J Hussey
- Department of Biosciences, University of Durham, South Road, Durham, DH1 3LE, UK.
| | - Silke Robatzek
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK.
- LMU Munich Biocenter, Großhadener Strasse 4, 82152, Planegg, DE, Germany.
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4
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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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5
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Chen W, Hu Z, Yu M, Zhu S, Xing J, Song L, Pu W, Yu F. A molecular link between autophagy and circadian rhythm in plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1044-1058. [PMID: 35297190 DOI: 10.1111/jipb.13250] [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: 01/05/2022] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Extremely high or low autophagy levels disrupt plant survival under nutrient starvation. Recently, autophagy has been reported to display rhythms in animals. However, the mechanism of circadian regulation of autophagy is still unclear. Here, we observed that autophagy has a robust rhythm and that various autophagy-related genes (ATGs) are rhythmically expressed in Arabidopsis. Chromatin immunoprecipitation (ChIP) and dual-luciferase (LUC) analyses showed that the core oscillator gene TIMING OF CAB EXPRESSION 1 (TOC1) directly binds to the promoters of ATG (ATG1a, ATG2, and ATG8d) and negatively regulates autophagy activities under nutritional stress. Furthermore, autophagy defects might affect endogenous rhythms by reducing the rhythm amplitude of TOC1 and shortening the rhythm period of CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1). Autophagy is essential for the circadian clock pattern in seedling development and plant sensitivity to nutritional deficiencies. Taken together, our studies reveal a plant strategy in which the TOC1-ATG axis involved in autophagy-rhythm crosstalk to fine-tune the intensity of autophagy.
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Affiliation(s)
- Weijun Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
| | - Zhaotun Hu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
- Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province, School of Biological and Food Engineering, Huaihua College, Huaihua, 418008, China
| | - MengTing Yu
- Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province, School of Biological and Food Engineering, Huaihua College, Huaihua, 418008, China
| | - Sirui Zhu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
| | - Junjie Xing
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410125, China
| | - Limei Song
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
| | - Wenxuan Pu
- Technology Center, China Tobacco Hunan Industrial Co., Ltd., Changsha, 410007, China
| | - Feng Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410125, China
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6
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Kang BH, Anderson CT, Arimura SI, Bayer E, Bezanilla M, Botella MA, Brandizzi F, Burch-Smith TM, Chapman KD, Dünser K, Gu Y, Jaillais Y, Kirchhoff H, Otegui MS, Rosado A, Tang Y, Kleine-Vehn J, Wang P, Zolman BK. A glossary of plant cell structures: Current insights and future questions. THE PLANT CELL 2022; 34:10-52. [PMID: 34633455 PMCID: PMC8846186 DOI: 10.1093/plcell/koab247] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/29/2021] [Indexed: 05/03/2023]
Abstract
In this glossary of plant cell structures, we asked experts to summarize a present-day view of plant organelles and structures, including a discussion of outstanding questions. In the following short reviews, the authors discuss the complexities of the plant cell endomembrane system, exciting connections between organelles, novel insights into peroxisome structure and function, dynamics of mitochondria, and the mysteries that need to be unlocked from the plant cell wall. These discussions are focused through a lens of new microscopy techniques. Advanced imaging has uncovered unexpected shapes, dynamics, and intricate membrane formations. With a continued focus in the next decade, these imaging modalities coupled with functional studies are sure to begin to unravel mysteries of the plant cell.
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Affiliation(s)
- 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
| | - Charles T Anderson
- Department of Biology and Center for Lignocellulose Structure and Formation, The Pennsylvania State University, University Park, Pennsylvania 16802 USA
| | - Shin-ichi Arimura
- Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Emmanuelle Bayer
- Université de Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, Villenave d'Ornon F-33140, France
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Miguel A Botella
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortifruticultura Subtropical y Mediterránea “La Mayora,” Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Málaga 29071, Spain
| | - Federica Brandizzi
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, Michigan 48824 USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan 48824, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Kent D Chapman
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76203, USA
| | - Kai Dünser
- Faculty of Biology, Chair of Molecular Plant Physiology (MoPP) University of Freiburg, Freiburg 79104, Germany
- Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, Freiburg 79104, Germany
| | - Yangnan Gu
- Department of Plant and Microbial Biology, Innovative Genomics Institute, University of California, Berkeley, California 94720, USA
| | - Yvon Jaillais
- Laboratoire Reproduction et Développement des Plantes (RDP), Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, Lyon, France
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, USA
| | - Marisa S Otegui
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Wisconsin 53706, USA
| | - Abel Rosado
- Department of Botany, University of British Columbia, Vancouver V6T1Z4, Canada
| | - Yu Tang
- Department of Plant and Microbial Biology, Innovative Genomics Institute, University of California, Berkeley, California 94720, USA
| | - Jürgen Kleine-Vehn
- Faculty of Biology, Chair of Molecular Plant Physiology (MoPP) University of Freiburg, Freiburg 79104, Germany
- Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, Freiburg 79104, Germany
| | - Pengwei Wang
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Bethany Karlin Zolman
- Department of Biology, University of Missouri, St. Louis, St. Louis, Missouri 63121, USA
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7
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The Landscape of Autophagy-Related (ATG) Genes and Functional Characterization of TaVAMP727 to Autophagy in Wheat. Int J Mol Sci 2022; 23:ijms23020891. [PMID: 35055085 PMCID: PMC8776105 DOI: 10.3390/ijms23020891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Autophagy is an indispensable biological process and plays crucial roles in plant growth and plant responses to both biotic and abiotic stresses. This study systematically identified autophagy-related proteins (ATGs) in wheat and its diploid and tetraploid progenitors and investigated their genomic organization, structure characteristics, expression patterns, genetic variation, and regulation network. We identified a total of 77, 51, 29, and 30 ATGs in wheat, wild emmer, T. urartu and A. tauschii, respectively, and grouped them into 19 subfamilies. We found that these autophagy-related genes (ATGs) suffered various degrees of selection during the wheat’s domestication and breeding processes. The genetic variations in the promoter region of Ta2A_ATG8a were associated with differences in seed size, which might be artificially selected for during the domestication process of tetraploid wheat. Overexpression of TaVAMP727 improved the cold, drought, and salt stresses resistance of the transgenic Arabidopsis and wheat. It also promoted wheat heading by regulating the expression of most ATGs. Our findings demonstrate how ATGs regulate wheat plant development and improve abiotic stress resistance. The results presented here provide the basis for wheat breeding programs for selecting varieties of higher yield which are capable of growing in colder, drier, and saltier areas.
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8
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Rayevsky A, Ozheredov DS, Samofalova D, Ozheredov SP, Karpov PA, Blume YB. The Role of Posttranslational Acetylation in the Association of Autophagy Protein ATG8 with Microtubules in Plant Cells. CYTOL GENET+ 2021. [DOI: 10.3103/s0095452721060128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ishida H, Okashita Y, Ishida H, Hayashi M, Izumi M, Makino A, Bhuiyan NH, van Wijk KJ. GFS9 Affects Piecemeal Autophagy of Plastids in Young Seedlings of Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2021; 62:1372-1386. [PMID: 34086965 DOI: 10.1093/pcp/pcab084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 05/26/2021] [Accepted: 06/04/2021] [Indexed: 06/12/2023]
Abstract
Chloroplasts, and plastids in general, contain abundant protein pools that can be major sources of carbon and nitrogen for recycling. We have previously shown that chloroplasts are partially and sequentially degraded by piecemeal autophagy via the Rubisco-containing body. This degradation occurs during plant development and in response to the environment; however, little is known about the fundamental underlying mechanisms. To discover the mechanisms of piecemeal autophagy of chloroplasts/plastids, we conducted a forward-genetics screen following ethyl-methanesulfonate mutagenesis of an Arabidopsis (Arabidopsis thaliana) transgenic line expressing chloroplast-targeted green fluorescent protein (CT-GFP). This screen allowed us to isolate a mutant, gfs9-5, which hyperaccumulated cytoplasmic bodies labeled with CT-GFP of up to 1.0 μm in diameter in the young seedlings. We termed these structures plastid bodies (PBs). The mutant was defective in a membrane-trafficking factor, green fluorescent seed 9 (GFS9), and PB accumulation in gfs9-5 was promoted by darkness and nutrient deficiency. Transmission electron microscopy indicated that gfs9-5 hyperaccumulated structures corresponding to autophagosomes and PBs. gfs9-5 hyperaccumulated membrane-bound endogenous ATG8 proteins, transgenic yellow fluorescent protein (YFP)-ATG8e proteins and autophagosome-like structures labeled with YFP-ATG8e. The YFP-ATG8e signal was associated with the surface of plastids and their protrusions in gfs9-5. Double mutants of gfs9 and autophagy-defective 5 did not accumulate PBs. In gfs9-5, the YFP-ATG8e proteins and PBs could be delivered to the vacuole and autophagic flux was increased. We discuss a possible connection between GFS9 and autophagy and propose a potential use of gfs9-5 as a new tool to study piecemeal plastid autophagy.
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Affiliation(s)
- Hiroyuki Ishida
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba, Sendai 980-8572, Japan
- School of Integrative Plant Sciences, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA
| | - Yu Okashita
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba, Sendai 980-8572, Japan
| | - Hiromi Ishida
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba, Sendai 980-8572, Japan
- School of Integrative Plant Sciences, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA
| | - Makoto Hayashi
- Department of Bioscience, Nagahama Institute of Bioscience and Technology, Tamura 1266, Nagahama, Shiga 526-0829, Japan
| | - Masanori Izumi
- Center for Sustainable Resource Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Amane Makino
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba, Sendai 980-8572, Japan
| | - Nazmul H Bhuiyan
- School of Integrative Plant Sciences, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA
- Eurofins Lancaster Lab PSS, Richmond, VA, USA
| | - Klaas J van Wijk
- School of Integrative Plant Sciences, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA
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10
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Inácio V, Lobato C, Graça J, Morais-Cecílio L. Cork cells in cork oak periderms undergo programmed cell death and proanthocyanidin deposition. TREE PHYSIOLOGY 2021; 41:1701-1713. [PMID: 33611604 DOI: 10.1093/treephys/tpab031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 12/07/2020] [Accepted: 02/15/2021] [Indexed: 06/12/2023]
Abstract
Vascular plants with secondary growth develop a periderm mostly composed of dead suberized cork cells to face environmental hostile conditions. Cork oak has a highly active and long-living phellogen forming a remarkably thick periderm that is periodically debarked for industrial purposes. This wounding originates the quick formation of a new traumatic periderm, making cork oak an exceptional model to study the first periderm differentiation during normal development in young sprigs and traumatic (wound) periderm formation after debarking. Here, we studied the poorly known first periderm differentiation steps that involve cell wall suberization, polyphenolic accumulation and programmed cell death (PCD) by combining transmission electron microscopy, histochemical and molecular methods in periderms from young sprigs. These processes were further compared with traumatic periderms formed after wounding using molecular and histochemical techniques, such as the polyphenolic accumulation. In the first periderms from young sprigs, four distinct differentiation stages were defined according to the presence of PCD morphological features. First young and traumatic periderms showed an upregulation of genes related to suberin biosynthesis, proanthocyanidins biosynthesis and transport, autophagy, and PCD. Traumatic periderms revealed an overall upregulation of these genes, likely resulting from ontogeny differences and distinct phellogen origin associated with a faster metabolism, highlighting the impact of wounding on phellogen activity after debarking. First periderms from young sprigs showed gradual accumulation of proanthocyanidins in the vacuoles throughout PCD stages until total filled lumens, whereas in traumatic periderms, these compounds were found cell wall linked in already empty cells. This work enabled a comprehensive overview of the cork cells differentiation processes contributing to deepening the knowledge of the fundamental ontogenic program of this protective tissue, which is also a unique forest product, constituting the basis of a sustainable and profitable industry.
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Affiliation(s)
- Vera Inácio
- Linking Landscape, Environment, Agriculture and Food (LEAF), Institute of Agronomy, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, Portugal
- BioISI-Biosystems and Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Campo Grande 016, 1749-016 Lisboa, Portugal
| | - Carolina Lobato
- Linking Landscape, Environment, Agriculture and Food (LEAF), Institute of Agronomy, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, Portugal
- Institute of Environmental Biotechnology (UBT), Graz University of Technology, Petersgasse 12/I, 8010 Graz, Styria, Austria
| | - José Graça
- Forest Research Center (CEF), Institute of Agronomy, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, Portugal
| | - Leonor Morais-Cecílio
- Linking Landscape, Environment, Agriculture and Food (LEAF), Institute of Agronomy, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, Portugal
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11
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Field S, Conner WC, Roberts DM. Arabidopsis CALMODULIN-LIKE 38 Regulates Hypoxia-Induced Autophagy of SUPPRESSOR OF GENE SILENCING 3 Bodies. FRONTIERS IN PLANT SCIENCE 2021; 12:722940. [PMID: 34567037 PMCID: PMC8456008 DOI: 10.3389/fpls.2021.722940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/09/2021] [Indexed: 05/23/2023]
Abstract
During the energy crisis associated with submergence stress, plants restrict mRNA translation and rapidly accumulate stress granules that act as storage hubs for arrested mRNA complexes. One of the proteins associated with hypoxia-induced stress granules in Arabidopsis thaliana is the calcium-sensor protein CALMODULIN-LIKE 38 (CML38). Here, we show that SUPPRESSOR OF GENE SILENCING 3 (SGS3) is a CML38-binding protein, and that SGS3 and CML38 co-localize within hypoxia-induced RNA stress granule-like structures. Hypoxia-induced SGS3 granules are subject to turnover by autophagy, and this requires both CML38 as well as the AAA+-ATPase CELL DIVISION CYCLE 48A (CDC48A). CML38 also interacts directly with CDC48A, and CML38 recruits CDC48A to CML38 granules in planta. Together, this work demonstrates that SGS3 associates with stress granule-like structures during hypoxia stress that are subject to degradation by CML38 and CDC48-dependent autophagy. Further, the work identifies direct regulatory targets for the hypoxia calcium-sensor CML38, and suggest that CML38 association with stress granules and associated regulation of autophagy may be part of the RNA regulatory program during hypoxia stress.
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12
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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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13
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Zhen X, Zheng N, Yu J, Bi C, Xu F. Autophagy mediates grain yield and nitrogen stress resistance by modulating nitrogen remobilization in rice. PLoS One 2021; 16:e0244996. [PMID: 33444362 PMCID: PMC7808584 DOI: 10.1371/journal.pone.0244996] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 12/21/2020] [Indexed: 01/18/2023] Open
Abstract
Autophagy, a conserved cellular process in eukaryotes, has evolved to a sophisticated process to dispose of intracellular constituents and plays important roles in plant development, metabolism, and efficient nutrients remobilization under suboptimal nutrients conditions. Here, we show that OsATG8b, an AUTOPHAGY-RELATED8 (ATG8) gene in rice, was highly induced by nitrogen (N) starvation. Elevated expression of OsATG8b significantly increased ATG8 lipidation, autophagic flux, and grain yield in rice under both sufficient and deficient N conditions. Overexpressing of OsATG8b could greatly increase the activities of enzymes related to N metabolism. Intriguingly, the 15N-labeling assay further revealed that more N was remobilized to seeds in OsATG8b-overexpressing rice, which significantly increased the N remobilization efficiency (NRE), N harvest index, N utilization efficiency (NUE), and N uptake efficiency (NUpE). Conversely, the osatg8b knock-out mutants had the opposite results on these characters. The substantial transcriptional changes of the overexpressed transgenic lines indicated the presence of complex signaling to developmental, metabolic process, and hormone, etc. Excitingly, the transgenic rice under different backgrounds all similarly be boosted in yield and NUE with OsATG8b overexpression. This work provides an excellent candidate gene for improving N remobilization, utilization, and yield in crops simultaneously.
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Affiliation(s)
- Xiaoxi Zhen
- Key Laboratory of Northern Japonica Rice Genetics and Breeding, Ministry of Education and Liaoning Province, Key Laboratory of Northeast Rice Biology and Genetics and Breeding, Ministry of Agriculture, Rice Research Institute of Shenyang Agricultural University, Shenyang, China
- College of Agriculture, Shanxi Agricultural University, Taigu, China
| | - Naimeng Zheng
- Key Laboratory of Northern Japonica Rice Genetics and Breeding, Ministry of Education and Liaoning Province, Key Laboratory of Northeast Rice Biology and Genetics and Breeding, Ministry of Agriculture, Rice Research Institute of Shenyang Agricultural University, Shenyang, China
| | - Jinlei Yu
- Key Laboratory of Northern Japonica Rice Genetics and Breeding, Ministry of Education and Liaoning Province, Key Laboratory of Northeast Rice Biology and Genetics and Breeding, Ministry of Agriculture, Rice Research Institute of Shenyang Agricultural University, Shenyang, China
| | - Congyuan Bi
- Key Laboratory of Northern Japonica Rice Genetics and Breeding, Ministry of Education and Liaoning Province, Key Laboratory of Northeast Rice Biology and Genetics and Breeding, Ministry of Agriculture, Rice Research Institute of Shenyang Agricultural University, Shenyang, China
| | - Fan Xu
- Key Laboratory of Northern Japonica Rice Genetics and Breeding, Ministry of Education and Liaoning Province, Key Laboratory of Northeast Rice Biology and Genetics and Breeding, Ministry of Agriculture, Rice Research Institute of Shenyang Agricultural University, Shenyang, China
- * E-mail: ,
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14
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Xu L, Wang H, Zhang C, Wang J, Chen A, Chen Y, Ma Z. System-wide characterization of subtilases reveals that subtilisin-like protease FgPrb1 of Fusarium graminearum regulates fungal development and virulence. Fungal Genet Biol 2020; 144:103449. [PMID: 32890707 DOI: 10.1016/j.fgb.2020.103449] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 12/30/2022]
Abstract
Subtilases represent the second largest subfamily of serine proteases, and are important for various biological processes. However, the biological function of subtilases has not been systematically characterized in plant pathogens. In present study, 32 subtilases were identified in the genome of wheat scab fungus Fusarium graminearum, a devastating cereal plant pathogen. Deletion mutants of each subtilase were obtained and functionally characterized. Among them, the deletion of FgPrb1 resulted in greatly reduced virulence of F. graminearum. The regulatory mechanisms of FgPrb1 in virulence were investigated in details. Our results showed that the loss of FgPrb1 led to defects in deoxynivalenol (DON) production, responses to environmental stimuli, and lipid metabolism. Additionally, we found that FgPrb1 was involved in autophagy regulation. Taken together, the systematic functional characterization of subtilases showed that the FgPrb1 of F. graminearum is critical for plant infection by regulating multiple different cellular processes.
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Affiliation(s)
- Luona Xu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
| | - Hongkai Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
| | - Chengqi Zhang
- Department of Plant Pathology, College of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Jinli Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
| | - Ahai Chen
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China.
| | - Yun Chen
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
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15
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Sieńko K, Poormassalehgoo A, Yamada K, Goto-Yamada S. Microautophagy in Plants: Consideration of Its Molecular Mechanism. Cells 2020; 9:cells9040887. [PMID: 32260410 PMCID: PMC7226842 DOI: 10.3390/cells9040887] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 02/06/2023] Open
Abstract
Microautophagy is a type of autophagy. It is characterized by direct enclosing with the vacuolar/lysosomal membrane, which completes the isolation and uptake of cell components in the vacuole. Several publications present evidence that plants exhibit microautophagy. Plant microautophagy is involved in anthocyanin accumulation in the vacuole, eliminating damaged chloroplasts and degrading cellular components during starvation. However, information on the molecular mechanism of microautophagy is less available than that on the general macroautophagy, because the research focusing on microautophagy has not been widely reported. In yeast and animals, it is suggested that microautophagy can be classified into several types depending on morphology and the requirements of autophagy-related (ATG) genes. This review summarizes the studies on plant microautophagy and discusses possible techniques for a future study in this field while taking into account the information on microautophagy obtained from yeast and animals.
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16
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Kajikawa M, Fukuzawa H. Algal Autophagy Is Necessary for the Regulation of Carbon Metabolism Under Nutrient Deficiency. FRONTIERS IN PLANT SCIENCE 2020; 11:36. [PMID: 32117375 PMCID: PMC7012896 DOI: 10.3389/fpls.2020.00036] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/13/2020] [Indexed: 05/04/2023]
Abstract
Autophagy is a mechanism to recycle intracellular constituents such as amino acids and other carbon- and nitrogen (N)-containing compounds. Although autophagy-related (ATG) genes required for autophagy are encoded by many algal genomes, their functional importance in microalgae in nutrient-deficiency has not been appraised using ATG-defective mutants. Recently, by characterization of an insertional mutant of the ATG8 encoding a ubiquitin-like protein indispensable for autophagosome formation in a green alga Chlamydomonas reinhardtii, we have provided evidence that supports the following notions. ATG8 protein is required for the degradation of lipid droplets and triacylglycerol (TAG) triggered by resupply of N to cell culture in N-deficient conditions. ATG8 protein is also necessary for starch accumulation under phosphorus-deficient conditions. Algal autophagy is not necessary for inheritance of chloroplast and mitochondrial genomes. In this review, we discuss the physiological roles of algal autophagy associated with nutrient deficiency revealed by the genetic and biochemical analyses using disruption mutants and reagents that inhibit the fatty acid biosynthesis and vacuolar H+-ATPase.
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17
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Dündar G, Shao Z, Higashitani N, Kikuta M, Izumi M, Higashitani A. Autophagy mitigates high-temperature injury in pollen development of Arabidopsis thaliana. Dev Biol 2019; 456:190-200. [DOI: 10.1016/j.ydbio.2019.08.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 07/31/2019] [Accepted: 08/27/2019] [Indexed: 01/26/2023]
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18
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Dauphinee AN, Denbigh GL, Rollini A, Fraser M, Lacroix CR, Gunawardena AHLAN. The Function of Autophagy in Lace Plant Programmed Cell Death. FRONTIERS IN PLANT SCIENCE 2019; 10:1198. [PMID: 31695708 PMCID: PMC6817616 DOI: 10.3389/fpls.2019.01198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/30/2019] [Indexed: 05/07/2023]
Abstract
The lace plant (Aponogeton madagascariensis) is an aquatic monocot that utilizes programmed cell death (PCD) to form perforations throughout its mature leaves as part of normal development. The lace plant is an emerging model system representing a unique form of developmental PCD. The role of autophagy in lace plant PCD was investigated using live cell imaging, transmission electron microscopy (TEM), immunolocalization, and in vivo pharmacological experimentation. ATG8 immunostaining and acridine orange staining revealed that autophagy occurs in both healthy and dying cells. Autophagosome-like vesicles were also found in healthy and dying cells through ultrastructural analysis with TEM. Following autophagy modulation, there was a noticeable increase in vesicles and vacuolar aggregates. A novel cell death assay utilizing lace plant leaves revealed that autophagy enhancement with rapamycin significantly decreased cell death rates compared to the control, whereas inhibition of autophagosome formation with wortmannin or blocking the degradation of cargoes with concanamycin A had an opposite effect. Although autophagy modulation significantly affected cell death rates in cells that are destined to die, neither the promotion nor inhibition of autophagy in whole plants had a significant effect on the number of perforations formed in lace plant leaves. Our data indicate that autophagy predominantly contributes to cell survival, and we found no clear evidence for its direct involvement in the induction of developmental PCD during perforation formation in lace plant leaves.
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Affiliation(s)
- Adrian N. Dauphinee
- Department of Biology, Dalhousie University, Halifax, NS, Canada
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Alice Rollini
- Department of Biology, Dalhousie University, Halifax, NS, Canada
| | - Meredith Fraser
- Department of Biology, Dalhousie University, Halifax, NS, Canada
| | - Christian R. Lacroix
- Department of Biology, University of Prince Edward Island, Charlottetown, PE, Canada
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19
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Wang X, Liu Z, Fan F, Hou Y, Yang H, Meng X, Zhang Y, Ren F. Microfluidic chip and its application in autophagy detection. Trends Analyt Chem 2019. [DOI: 10.1016/j.trac.2019.05.043] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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20
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Kosmacz M, Gorka M, Schmidt S, Luzarowski M, Moreno JC, Szlachetko J, Leniak E, Sokolowska EM, Sofroni K, Schnittger A, Skirycz A. Protein and metabolite composition of Arabidopsis stress granules. THE NEW PHYTOLOGIST 2019; 222:1420-1433. [PMID: 30664249 DOI: 10.1111/nph.15690] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 01/11/2019] [Indexed: 05/06/2023]
Abstract
Stress granules (SGs) are evolutionary conserved aggregates of proteins and untranslated mRNAs formed in response to stress. Despite their importance for stress adaptation, no complete proteome composition has been reported for plant SGs. In this study, we addressed the existing gap. Importantly, we also provide evidence for metabolite sequestration within the SGs. To isolate SGs we used Arabidopsis seedlings expressing green fluorescent protein (GFP) fusion of the SGs marker protein, Rbp47b, and an experimental protocol combining differential centrifugation with affinity purification (AP). SGs isolates were analysed using mass spectrometry-based proteomics and metabolomics. A quarter of the identified proteins constituted known or predicted SG components. Intriguingly, the remaining proteins were enriched in key enzymes and regulators, such as cyclin-dependent kinase A (CDKA), that mediate plant responses to stress. In addition to proteins, nucleotides, amino acids and phospholipids also accumulated in SGs. Taken together, our results indicated the presence of a preexisting SG protein interaction network; an evolutionary conservation of the proteins involved in SG assembly and dynamics; an important role for SGs in moderation of stress responses by selective storage of proteins and metabolites.
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Affiliation(s)
- Monika Kosmacz
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Michał Gorka
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Stephan Schmidt
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Marcin Luzarowski
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Juan C Moreno
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Jagoda Szlachetko
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Ewa Leniak
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | | | - Kostika Sofroni
- Department of Developmental Biology, University of Hamburg, 22069, Hamburg, Germany
| | - Arp Schnittger
- Department of Developmental Biology, University of Hamburg, 22069, Hamburg, Germany
| | - Aleksandra Skirycz
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
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21
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Mei D, Chen B, He B, Liu H, Lin Z, Lin J, Zhang X, Sun N, Zhao L, Wang X, Zhang Q. Actively priming autophagic cell death with novel transferrin receptor-targeted nanomedicine for synergistic chemotherapy against breast cancer. Acta Pharm Sin B 2019; 9:1061-1077. [PMID: 31649854 PMCID: PMC6804482 DOI: 10.1016/j.apsb.2019.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/08/2019] [Accepted: 03/14/2019] [Indexed: 12/11/2022] Open
Abstract
Recently, considerable attention in the field of cancer therapy has been focused on the mammalian rapamycin target (mTOR), inhibition of which could result in autophagic cell death (ACD). Though novel combination chemotherapy of autophagy inducers with chemotherapeutic agents is extensively investigated, nanomedicine-based combination therapy for ACD remains in infancy. In attempt to actively trigger ACD for synergistic chemotherapy, here we incorporated autophagy inducer rapamycin (RAP) into 7pep-modified PEG-DSPE polymer micelles (7pep-M-RAP) to specifically target and efficiently priming ACD of MCF-7 human breast cancer cells with high expression of transferrin receptor (TfR). Cytotoxic paclitaxel (PTX)-loaded micelle (7pep-M-PTX) was regarded as chemotherapeutic drug model. We discovered that with superior intracellular uptake in vitro and more tumor accumulation of micelles in vivo, 7pep-M-RAP exhibited excellent autophagy induction and synergistic antitumor efficacy with 7pep-M-PTX. Mechanism study further revealed that 7pep-M-RAP and 7pep-M-PTX used in combination provided enhanced efficacy through induction of both apoptosis- and mitochondria-associated autophagic cell death. Together, our findings suggested that the targeted excess autophagy may provide a rational strategy to improve therapeutic outcome of breast cancer, and simultaneous induction of ACD and apoptosis may be a promising anticancer modality.
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22
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Rezabakhsh A, Rahbarghazi R, Malekinejad H, Fathi F, Montaseri A, Garjani A. Quercetin alleviates high glucose-induced damage on human umbilical vein endothelial cells by promoting autophagy. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2019; 56:183-193. [PMID: 30668339 DOI: 10.1016/j.phymed.2018.11.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/08/2018] [Accepted: 11/07/2018] [Indexed: 05/20/2023]
Abstract
BACKGROUND Quercetin, a flavonoid antioxidant, has been found to exert therapeutic effects in diabetic condition. Autophagy represents a homeostatic cellular mechanism for the turnover of unfolds proteins and damaged organelles through a lysosome-dependent degradation manner. We speculated that quercetin could protect endothelial cells against high glucose-induced damage by promoting autophagic responses. METHODS HUVECs viability was evaluated by MTT method. Griess and TBARS assays were used to monitor the levels of NO and MDA, respectively. Intracellular ROS generation was determined in DCFDA-stained cells analyzed by flow cytometry. To investigate the role of quercetin in endothelial cell migratory behavior, we used a scratch test. The level of autophagy proteins LC3, Beclin-1 and P62 were measured by western blotting technique. RESULTS Our results showed that quercetin had the potential to increase cell survival after exposure to high glucose (P < 0.05). Total levels of oxidative stress markers were profoundly decreased and the activity of GSH was increased by quercetin (P < 0.05). High glucose suppressed HUVECs migration to the scratched area (P < 0.05). However, a significant stimulation in cell migration was observed after exposure to quercetin (P < 0.05). Based on data, autophagy was blocked at the late stage by high glucose concentration while quercetin enhanced autophagic response by reducing the P62 level coincided with the induction of Beclin-1 and LC3-II to LC3-I ratio (P < 0.05). All these beneficial effects were reversed by 3-methyladenine as an autophagy inhibitor. CONCLUSION Together, our data suggest that quercetin could protect HUVECs from high glucose induced-damage possibly by activation of the autophagy response.
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Affiliation(s)
- Aysa Rezabakhsh
- Emergency Medicine Research Team, Tabriz University of Medical Sciences, Tabriz, Iran; Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Reza Rahbarghazi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Applied Cell Sciences, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Hassan Malekinejad
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran
| | - Farzaneh Fathi
- Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Azadeh Montaseri
- Department of Anatomical Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Alireza Garjani
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
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23
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Sedaghatmehr M, Thirumalaikumar VP, Kamranfar I, Marmagne A, Masclaux-Daubresse C, Balazadeh S. A regulatory role of autophagy for resetting the memory of heat stress in plants. PLANT, CELL & ENVIRONMENT 2019; 42:1054-1064. [PMID: 30136402 DOI: 10.1111/pce.13426] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 08/01/2018] [Accepted: 08/08/2018] [Indexed: 05/19/2023]
Abstract
As sessile life forms, plants are repeatedly confronted with adverse environmental conditions, which can impair development, growth, and reproduction. During evolution, plants have established mechanisms to orchestrate the delicate balance between growth and stress tolerance, to reset cellular biochemistry once stress vanishes, or to keep a molecular memory, which enables survival of a harsher stress that may arise later. Although there are several examples of memory in diverse plants species, the molecular machinery underlying the formation, duration, and resetting of stress memories is largely unknown so far. We report here that autophagy, a central self-degradative process, assists in resetting cellular memory of heat stress (HS) in Arabidopsis thaliana. Autophagy is induced by thermopriming (moderate HS) and, intriguingly, remains high long after stress termination. We demonstrate that autophagy mediates the specific degradation of heat shock proteins at later stages of the thermorecovery phase leading to the accumulation of protein aggregates after the second HS and a compromised heat tolerance. Autophagy mutants retain heat shock proteins longer than wild type and concomitantly display improved thermomemory. Our findings reveal a novel regulatory mechanism for HS memory in plants.
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Affiliation(s)
- Mastoureh Sedaghatmehr
- Department of Molecular Biology, University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Golm, Germany
- Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Golm, Germany
| | - Venkatesh P Thirumalaikumar
- Department of Molecular Biology, University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Golm, Germany
- Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Golm, Germany
| | - Iman Kamranfar
- Department of Molecular Biology, University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Golm, Germany
| | - Anne Marmagne
- Institut Jean-Pierre Bourgin (IJPB), INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Celine Masclaux-Daubresse
- Institut Jean-Pierre Bourgin (IJPB), INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Salma Balazadeh
- Department of Molecular Biology, University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Golm, Germany
- Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Golm, Germany
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24
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Chen Q, Soulay F, Saudemont B, Elmayan T, Marmagne A, Masclaux-Daubresse CL. Overexpression of ATG8 in Arabidopsis Stimulates Autophagic Activity and Increases Nitrogen Remobilization Efficiency and Grain Filling. PLANT & CELL PHYSIOLOGY 2019; 60:343-352. [PMID: 30407574 DOI: 10.1093/pcp/pcy214] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/27/2018] [Indexed: 05/20/2023]
Abstract
Autophagy knock-out mutants in maize and in Arabidopsis are impaired in nitrogen (N) recycling and exhibit reduced levels of N remobilization to their seeds. It is thus impoortant to determine whether higher autophagy activity could, conversely, improve N remobilization efficiency and seed protein content, and under what circumstances. As the autophagy machinery involves many genes amongst which 18 are important for the core machinery, the choice of which AUTOPHAGY (ATG) gene to manipulate to increase autophagy was examined. We choose ATG8 overexpression since it has been shown that this gene could increase autophagosome size and autophagic activity in yeast. The results we report here are original as they show for the first time that increasing ATG8 gene expression in plants increases autophagosome number and promotes autophagy activity. More importantly, our data demonstrate that, when cultivated under full nitrate conditions, known to repress N remobilization due to sufficient N uptake from the soil, N remobilization efficiency can nevertheless be sharply and significantly increased by overexpressing ATG8 genomic sequences under the control of the ubiquitin promoter. We show that overexpressors have improved seed N% and at the same time reduced N waste in their dry remains. In addition, we show that overexpressing ATG8 does not modify vegetative biomass or harvest index, and thus does not affect plant development.
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Affiliation(s)
- Qinwu Chen
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universit� Paris-Saclay, Versailles, France
| | - Fabienne Soulay
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universit� Paris-Saclay, Versailles, France
| | - Baptiste Saudemont
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universit� Paris-Saclay, Versailles, France
| | - Taline Elmayan
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universit� Paris-Saclay, Versailles, France
| | - Anne Marmagne
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universit� Paris-Saclay, Versailles, France
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25
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Abstract
Plants have evolved sophisticated mechanisms to recycle intracellular constituents, which are essential for developmental and metabolic transitions; for efficient nutrient reuse; and for the proper disposal of proteins, protein complexes, and even entire organelles that become obsolete or dysfunctional. One major route is autophagy, which employs specialized vesicles to encapsulate and deliver cytoplasmic material to the vacuole for breakdown. In the past decade, the mechanics of autophagy and the scores of components involved in autophagic vesicle assembly have been documented. Now emerging is the importance of dedicated receptors that help recruit appropriate cargo, which in many cases exploit ubiquitylation as a signal. Although operating at a low constitutive level in all plant cells, autophagy is upregulated during senescence and various environmental challenges and is essential for proper nutrient allocation. Its importance to plant metabolism and energy balance in particular places autophagy at the nexus of robust crop performance, especially under suboptimal conditions.
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Affiliation(s)
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, USA;
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26
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Kang S, Shin KD, Kim JH, Chung T. Autophagy-related (ATG) 11, ATG9 and the phosphatidylinositol 3-kinase control ATG2-mediated formation of autophagosomes in Arabidopsis. PLANT CELL REPORTS 2018; 37:653-664. [PMID: 29350244 DOI: 10.1007/s00299-018-2258-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 01/11/2018] [Indexed: 05/06/2023]
Abstract
Using quantitative assays for autophagy, we analyzed 4 classes of atg mutants, discovered new atg2 phenotypes and ATG gene interactions, and proposed a model of autophagosome formation in plants. Plant and other eukaryotic cells use autophagy to target cytoplasmic constituents for degradation in the vacuole. Autophagy is regulated and executed by a conserved set of proteins called autophagy-related (ATG). In Arabidopsis, several groups of ATG proteins have been characterized using genetic approaches. However, the genetic interactions between ATG genes have not been established and the relationship between different ATG groups in plants remains unclear. Here we analyzed atg2, atg7, atg9, and atg11 mutants and their double mutants at the physiological, biochemical, and subcellular levels. Involvement of phosphatidylinositol 3-kinase (PI3K) in autophagy was also tested using wortmannin, a PI3K inhibitor. Our mutant analysis using autophagy markers showed that atg7 and atg2 phenotypes are more severe than those of atg11 and atg9. Unlike other mutants, atg2 cells accumulated several autophagic vesicles that could not be delivered to the vacuole. Analysis of atg double mutants, combined with wortmannin treatment, indicated that ATG11, PI3K, and ATG9 act upstream of ATG2. Our data support a model in which plant ATG1 and PI3K complexes play a role in the initiation of autophagy, whereas ATG2 is involved in a later step during the biogenesis of autophagic vesicles.
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Affiliation(s)
- Sangwoo Kang
- Department of Biological Sciences, Pusan National University, Geumjeong-gu, Busan, 46241, Republic of Korea
| | - Kwang Deok Shin
- Department of Biological Sciences, Pusan National University, Geumjeong-gu, Busan, 46241, Republic of Korea
| | - Jeong Hun Kim
- Department of Biological Sciences, Pusan National University, Geumjeong-gu, Busan, 46241, Republic of Korea
| | - Taijoon Chung
- Department of Biological Sciences, Pusan National University, Geumjeong-gu, Busan, 46241, Republic of Korea.
- Institute of Systems Biology, Pusan National University, Geumjeong-gu, Busan, 46241, Republic of Korea.
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27
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Involvement of estrogen receptors in silibinin protection of pancreatic β-cells from TNFα- or IL-1β-induced cytotoxicity. Biomed Pharmacother 2018; 102:344-353. [PMID: 29571019 DOI: 10.1016/j.biopha.2018.01.128] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/26/2018] [Accepted: 01/28/2018] [Indexed: 01/09/2023] Open
Abstract
Silibinin is a polyphenolic flavonoid that exhibits anticarcinogenic, anti-inflammatory and cytoprotective effects. The effect of silibinin on pancreatic islet β-cell is yet largely unknown in spite of well documented-hepatoprotective effects. Protecting the functional insulin-producing β-cells in the pancreas is a major therapeutic challenge in the patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM). This study reports the effect of silibinin on the rat pancreatic β-cell line, INS-1, damaged with pro-inflammatory cytokine, TNFα or IL-1β. Exposure to TNFα or IL-1β for 48 h caused INS-1 cells to reduce the production of insulin as well as cell viability. These actions of TNFα or IL-1β are associated with suppression of the expression of estrogen receptors (ERs). Further study revealed that silibinin protected the suppression in the expression of both ERα and ERβ that were involved in insulin synthesis and release, respectively. Furthermore, evidence is obtained that silibinin may impede the loss of critical INS-1 cells by promoting autophagy and preventing apoptosis. Direct cytoprotective effects of silibinin on INS-1 cells suggest that silibinin may be therapeutically beneficial for diabetes.
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28
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Enrique Gomez R, Joubès J, Valentin N, Batoko H, Satiat-Jeunemaître B, Bernard A. Lipids in membrane dynamics during autophagy in plants. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1287-1299. [PMID: 29140451 DOI: 10.1093/jxb/erx392] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/09/2017] [Indexed: 05/19/2023]
Abstract
Autophagy is a critical pathway for plant adaptation to stress. Macroautophagy relies on the biogenesis of a specialized membrane named the phagophore that maturates into a double membrane vesicle. Proteins and lipids act synergistically to promote membrane structure and functions, yet research on autophagy has mostly focused on autophagy-related proteins while knowledge of supporting lipids in the formation of autophagic membranes remains scarce. This review expands on studies in plants with examples from other organisms to present and discuss our current understanding of lipids in membrane dynamics associated with the autophagy pathway in plants.
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Affiliation(s)
- Rodrigo Enrique Gomez
- CNRS, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
- Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
| | - Jérôme Joubès
- CNRS, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
- Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
| | - Nicolas Valentin
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Paris-Sud University, Avenue de la Terrasse, Gif-sur-Yvette, France
| | - Henri Batoko
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, Louvain-la-Neuve, Belgium
| | - Béatrice Satiat-Jeunemaître
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Paris-Sud University, Avenue de la Terrasse, Gif-sur-Yvette, France
| | - Amélie Bernard
- CNRS, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
- Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
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29
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Bárány I, Berenguer E, Solís MT, Pérez-Pérez Y, Santamaría ME, Crespo JL, Risueño MC, Díaz I, Testillano PS. Autophagy is activated and involved in cell death with participation of cathepsins during stress-induced microspore embryogenesis in barley. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1387-1402. [PMID: 29309624 PMCID: PMC6019037 DOI: 10.1093/jxb/erx455] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/30/2017] [Indexed: 05/02/2023]
Abstract
Microspores are reprogrammed towards embryogenesis by stress. Many microspores die after this stress, limiting the efficiency of microspore embryogenesis. Autophagy is a degradation pathway that plays critical roles in stress response and cell death. In animals, cathepsins have an integral role in autophagy by degrading autophagic material; less is known in plants. Plant cathepsins are papain-like C1A cysteine proteases involved in many physiological processes, including programmed cell death. We have analysed the involvement of autophagy in cell death, in relation to cathepsin activation, during stress-induced microspore embryogenesis in Hordeum vulgare. After stress, reactive oxygen species (ROS) and cell death increased and autophagy was activated, including HvATG5 and HvATG6 up-regulation and increase of ATG5, ATG8, and autophagosomes. Concomitantly, cathepsin L/F-, B-, and H-like activities were induced, cathepsin-like genes HvPap-1 and HvPap-6 were up-regulated, and HvPap-1, HvPap-6, and HvPap-19 proteins increased and localized in the cytoplasm, resembling autophagy structures. Inhibitors of autophagy and cysteine proteases reduced cell death and promoted embryogenesis. The findings reveal a role for autophagy in stress-induced cell death during microspore embryogenesis, and the participation of cathepsins. Similar patterns of activation, expression, and localization suggest a possible connection between cathepsins and autophagy. The results open up new possibilities to enhance microspore embryogenesis efficiency with autophagy and/or cysteine protease modulators.
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Affiliation(s)
| | | | | | | | | | - José Luis Crespo
- Institute of Plant Biochemistry and Photosynthesis, IBVF, CSIC, Seville, Spain
| | | | - Isabel Díaz
- Center of Plant Biotechnology and Genomics, CBGP, UPM, Madrid, Spain
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30
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Couso I, Pérez-Pérez ME, Martínez-Force E, Kim HS, He Y, Umen JG, Crespo JL. Autophagic flux is required for the synthesis of triacylglycerols and ribosomal protein turnover in Chlamydomonas. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1355-1367. [PMID: 29053817 PMCID: PMC6018900 DOI: 10.1093/jxb/erx372] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 09/28/2017] [Indexed: 05/19/2023]
Abstract
Autophagy is an intracellular catabolic process that allows cells to recycle unneeded or damaged material to maintain cellular homeostasis. This highly dynamic process is characterized by the formation of double-membrane vesicles called autophagosomes, which engulf and deliver the cargo to the vacuole. Flow of material through the autophagy pathway and its degradation in the vacuole is known as autophagic flux, and reflects the autophagic degradation activity. A number of assays have been developed to determine autophagic flux in yeasts, mammals, and plants, but it has not been examined yet in algae. Here we analyzed autophagic flux in the model green alga Chlamydomonas reinhardtii. By monitoring specific autophagy markers such as ATG8 lipidation and using immunofluorescence and electron microscopy techniques, we show that concanamycin A, a vacuolar ATPase inhibitor, blocks autophagic flux in Chlamydomonas. Our results revealed that vacuolar lytic function is needed for the synthesis of triacylglycerols and the formation of lipid bodies in nitrogen- or phosphate-starved cells. Moreover, we found that concanamycin A treatment prevented the degradation of ribosomal proteins RPS6 and RPL37 under nitrogen or phosphate deprivation. These results indicate that autophagy might play an important role in the regulation of lipid metabolism and the recycling of ribosomal proteins under nutrient limitation in Chlamydomonas.
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Affiliation(s)
- Inmaculada Couso
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Seville, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Seville, Spain
| | - Enrique Martínez-Force
- Instituto de la Grasa (CSIC), Edificio 46, Campus Universitario Pablo de Olavide, Seville, Spain
| | - Hee-Sik Kim
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Yonghua He
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - James G Umen
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Seville, Spain
- Correspondence:
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31
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Monitoring Autophagy in the Model Green Microalga Chlamydomonas reinhardtii. Cells 2017; 6:cells6040036. [PMID: 29065500 PMCID: PMC5755495 DOI: 10.3390/cells6040036] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/17/2017] [Accepted: 10/19/2017] [Indexed: 01/19/2023] Open
Abstract
Autophagy is an intracellular catabolic system that delivers cytoplasmic constituents and organelles in the vacuole. This degradative process is mediated by a group of proteins coded by autophagy-related (ATG) genes that are widely conserved from yeasts to plants and mammals. Homologs of ATG genes have been also identified in algal genomes including the unicellular model green alga Chlamydomonas reinhardtii. The development of specific tools to monitor autophagy in Chlamydomonas has expanded our current knowledge about the regulation and function of this process in algae. Recent findings indicated that autophagy is regulated by redox signals and the TOR network in Chlamydomonas and revealed that this process may play in important role in the control of lipid metabolism and ribosomal protein turnover in this alga. Here, we will describe the different techniques and approaches that have been reported to study autophagy and autophagic flux in Chlamydomonas.
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32
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Ueno N, Nihei S, Miyakawa N, Hirasawa T, Kanekatsu M, Marubashi W, van Doorn WG, Yamada T. Time course of programmed cell death, which included autophagic features, in hybrid tobacco cells expressing hybrid lethality. PLANT CELL REPORTS 2016; 35:2475-2488. [PMID: 27585575 DOI: 10.1007/s00299-016-2048-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/27/2016] [Indexed: 06/06/2023]
Abstract
KEY MESSAGE PCD with features of vacuolar cell death including autophagy-related features were detected in hybrid tobacco cells, and detailed time course of features of vacuolar cell death were established. A type of interspecific Nicotiana hybrid, Nicotiana suaveolens × N. tabacum exhibits temperature-sensitive lethality. This lethality results from programmed cell death (PCD) in hybrid seedlings, but this PCD occurs only in seedlings and suspension-cultured cells grown at 28 °C, not those grown at 36 °C. Plant PCD can be classified as vacuolar cell death or necrotic cell death. Induction of autophagy, vacuolar membrane collapse and actin disorganization are each known features of vacuolar cell death, but observed cases of PCD showing all these features simultaneously are rare. In this study, these features of vacuolar cell death were evident in hybrid tobacco cells expressing hybrid lethality. Ion leakage, plasma membrane disruption, increased activity of vacuolar processing enzyme, vacuolar membrane collapse, and formation of punctate F-actin foci were each evident in these cells. Transmission electron microscopy revealed that macroautophagic structures formed and tonoplasts ruptured in these cells. The number of cells that contained monodansylcadaverine (MDC)-stained structures and the abundance of nine autophagy-related gene transcripts increased just before cell death at 28 °C; these features were not evident at 36 °C. We assessed whether an autophagic inhibitor, wortmannin (WM), influenced lethality in hybrid cells. After the hybrid cell began to die, WM suppressed increases in ion leakage and cell deaths, and it decreased the number of cells containing MDC-stained structures. These results showed that several features indicative of autophagy and vacuolar cell death were evident in the hybrid tobacco cells subject to lethality. In addition, we documented a detailed time course of these vacuolar cell death features.
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Affiliation(s)
- Naoya Ueno
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Saori Nihei
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Naoto Miyakawa
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Tadashi Hirasawa
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
- Global Innovation Research Organization, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Motoki Kanekatsu
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Wataru Marubashi
- Faculty of Agricultural Science, Meiji University, Kanagawa, Japan
| | - Wouter G van Doorn
- Mann Laboratory, Department of Plant Sciences, University of California, Davis, CA, USA
- Global Innovation Research Organization, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Tetsuya Yamada
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan.
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan.
- Global Innovation Research Organization, Tokyo University of Agriculture and Technology, Tokyo, Japan.
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33
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Floyd BE, Morriss SC, MacIntosh GC, Bassham DC. Evidence for autophagy-dependent pathways of rRNA turnover in Arabidopsis. Autophagy 2016; 11:2199-212. [PMID: 26735434 DOI: 10.1080/15548627.2015.1106664] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Ribosomes account for a majority of the cell's RNA and much of its protein and represent a significant investment of cellular resources. The turnover and degradation of ribosomes has been proposed to play a role in homeostasis and during stress conditions. Mechanisms for the turnover of rRNA and ribosomal proteins have not been fully elucidated. We show here that the RNS2 ribonuclease and autophagy participate in RNA turnover in Arabidopsis thaliana under normal growth conditions. An increase in autophagosome formation was seen in an rns2-2 mutant, and this increase was dependent on the core autophagy genes ATG9 and ATG5. Autophagosomes and autophagic bodies in rns2-2 mutants contain RNA and ribosomes, suggesting that autophagy is activated as an attempt to compensate for loss of rRNA degradation. Total RNA accumulates in rns2-2, atg9-4, atg5-1, rns2-2 atg9-4, and rns2-2 atg5-1 mutants, suggesting a parallel role for autophagy and RNS2 in RNA turnover. rRNA accumulates in the vacuole in rns2-2 mutants. Vacuolar accumulation of rRNA was blocked by disrupting autophagy via an rns2-2 atg5-1 double mutant but not by an rns2-2 atg9-4 double mutant, indicating that ATG5 and ATG9 function differently in this process. Our results suggest that autophagy and RNS2 are both involved in homeostatic degradation of rRNA in the vacuole.
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Affiliation(s)
- Brice E Floyd
- a Department of Genetics , Development and Cell Biology; Iowa State University ; Ames , IA , USA
| | - Stephanie C Morriss
- b Roy J. Carver Department of Biochemistry Biophysics and Molecular Biology; Iowa State University ; Ames , IA USA
| | - Gustavo C MacIntosh
- b Roy J. Carver Department of Biochemistry Biophysics and Molecular Biology; Iowa State University ; Ames , IA USA.,c Plant Sciences Institute; Iowa State University ; Ames , IA USA
| | - Diane C Bassham
- a Department of Genetics , Development and Cell Biology; Iowa State University ; Ames , IA , USA.,c Plant Sciences Institute; Iowa State University ; Ames , IA USA
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Uemura T. Physiological Roles of Plant Post-Golgi Transport Pathways in Membrane Trafficking. PLANT & CELL PHYSIOLOGY 2016; 57:2013-2019. [PMID: 27649735 DOI: 10.1093/pcp/pcw149] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/12/2016] [Indexed: 05/02/2023]
Abstract
Membrane trafficking is the fundamental system through which proteins are sorted to their correct destinations in eukaryotic cells. Key regulators of this system include RAB GTPases and soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs). Interestingly, the numbers of RAB GTPases and SNAREs involved in post-Golgi transport pathways in plant cells are larger than those in animal and yeast cells, suggesting that plants have evolved unique and complex post-Golgi transport pathways. The trans-Golgi network (TGN) is an important organelle that acts as a sorting station in the post-Golgi transport pathways of plant cells. The TGN also functions as the early endosome, which is the first compartment to receive endocytosed proteins. Several endocytosed proteins on the plasma membrane (PM) are initially targeted to the TGN/EE, then recycled back to the PM or transported to the vacuole for degradation. The recycling and degradation of the PM localized proteins is essential for the development and environmental responses in plant. The present review describes the post-Golgi transport pathways that show unique physiological functions in plants.
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Affiliation(s)
- Tomohiro Uemura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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35
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Identification of Barley (Hordeum vulgare L.) Autophagy Genes and Their Expression Levels during Leaf Senescence, Chronic Nitrogen Limitation and in Response to Dark Exposure. AGRONOMY-BASEL 2016. [DOI: 10.3390/agronomy6010015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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36
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Escamez S, André D, Zhang B, Bollhöner B, Pesquet E, Tuominen H. METACASPASE9 modulates autophagy to confine cell death to the target cells during Arabidopsis vascular xylem differentiation. Biol Open 2016; 5:122-9. [PMID: 26740571 PMCID: PMC4823987 DOI: 10.1242/bio.015529] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We uncovered that the level of autophagy in plant cells undergoing programmed cell death determines the fate of the surrounding cells. Our approach consisted of using Arabidopsis thaliana cell cultures capable of differentiating into two different cell types: vascular tracheary elements (TEs) that undergo programmed cell death (PCD) and protoplast autolysis, and parenchymatic non-TEs that remain alive. The TE cell type displayed higher levels of autophagy when expression of the TE-specific METACASPASE9 (MC9) was reduced using RNAi (MC9-RNAi). Misregulation of autophagy in the MC9-RNAi TEs coincided with ectopic death of the non-TEs, implying the existence of an autophagy-dependent intercellular signalling from within the TEs towards the non-TEs. Viability of the non-TEs was restored when AUTOPHAGY2 (ATG2) was downregulated specifically in MC9-RNAi TEs, demonstrating the importance of autophagy in the spatial confinement of cell death. Our results suggest that other eukaryotic cells undergoing PCD might also need to tightly regulate their level of autophagy to avoid detrimental consequences for the surrounding cells. Summary: In cell cultures that simulate Arabidopsis xylem differentiation, METACASPASE9 modulates the level of autophagy during programmed cell death to prevent ectopic death of the surrounding cells.
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Affiliation(s)
- Sacha Escamez
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå 90187, Sweden
| | - Domenique André
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå 90187, Sweden
| | - Bo Zhang
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå 90187, Sweden
| | - Benjamin Bollhöner
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå 90187, Sweden
| | - Edouard Pesquet
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå 90187, Sweden
| | - Hannele Tuominen
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå 90187, Sweden
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38
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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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Li Y, Li B, Liu L, Chen H, Zhang H, Zheng X, Zhang Z. FgMon1, a guanine nucleotide exchange factor of FgRab7, is important for vacuole fusion, autophagy and plant infection in Fusarium graminearum. Sci Rep 2015; 5:18101. [PMID: 26657788 PMCID: PMC4674805 DOI: 10.1038/srep18101] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/11/2015] [Indexed: 11/08/2022] Open
Abstract
The Ccz1-Mon1 protein complex, the guanine nucleotide exchange factor (GEF) of the late endosomal Rab7 homolog Ypt7, is required for the late step of multiple vacuole delivery pathways, such as cytoplasm-to-vacuole targeting (Cvt) pathway and autophagy processes. Here, we identified and characterized the yeast Mon1 homolog in Fusarium graminearum, named FgMon1. FgMON1 encodes a trafficking protein and is well conserved in filamentous fungi. Targeted gene deletion showed that the ∆Fgmon1 mutant was defective in vegetative growth, asexual/sexual development, conidial germination and morphology, plant infection and deoxynivalenol production. Cytological examination revealed that the ∆Fgmon1 mutant was also defective in vacuole fusion and autophagy, and delayed in endocytosis. Yeast two hybrid and in vitro GST-pull down assays approved that FgMon1 physically interacts with a Rab GTPase FgRab7 which is also important for the development, infection, membrane fusion and autophagy in F. graminearum. FgMon1 likely acts as a GEF of FgRab7 and constitutively activated FgRab7 was able to rescue the defects of the ∆Fgmon1 mutant. In summary, our study provides evidences that FgMon1 and FgRab7 are critical components that modulate vesicle trafficking, endocytosis and autophagy, and thereby affect the development, plant infection and DON production of F. graminearum.
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Affiliation(s)
- Ying Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China
| | - Bing Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China
| | - Luping Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China
| | - Huaigu Chen
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Haifeng Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China
| | - Xiaobo Zheng
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China
| | - Zhengguang Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China
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Desclos-Théveniau M, Coquet L, Jouenne T, Etienne P. Proteomic analysis of residual proteins in blades and petioles of fallen leaves of Brassica napus. PLANT BIOLOGY (STUTTGART, GERMANY) 2015; 17:408-418. [PMID: 25294336 DOI: 10.1111/plb.12241] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 07/04/2014] [Indexed: 06/03/2023]
Abstract
Brassica napus L. is an important crop plant, characterised by high nitrogen (N) levels in fallen leaves, leading to a significant restitution of this element to the soil, with important consequences at the economic and environmental levels. It is now well established that the N in fallen leaves is due to weak N remobilisation that is especially related to incomplete degradation of foliar proteins during leaf senescence. Identification of residual proteins in a fallen leaf (i.e. incompletely degraded in the last step of the N remobilisation process) constitutes important information for improving nutrient use efficiency. Proteome analysis of the vascular system (petioles) and blades from fallen leaves of Brassica napus was performed, and the 30 most abundant residual proteins in each tissue were identified. Among them, several proteins involved in N recycling remain in the leaf after abscission. Moreover, this study reveals that some residual proteins are associated with energy metabolism, protection against oxidative stress, and more surprisingly, photosynthesis. Finally, comparison of blade and petiole proteomes show that, despite their different physiological roles in the non-senescing leaf, both organs redirect their metabolism in order to ensure catabolic reactions. Taken together, the results suggest that a better degradation of these leaf proteins during the senescence process could enable improvements in the N use efficiency of Brassica napus.
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Affiliation(s)
- M Desclos-Théveniau
- Normandie University, Caen, France; UNICAEN, UMR 950 Ecophysiologie Végétale, Agronomie et nutritions N, C, S, Caen, France; INRA, UMR 950 Ecophysiologie Végétale, Agronomie et nutritions N, C, S, Caen, France
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Voitsekhovskaja OV, Schiermeyer A, Reumann S. Plant peroxisomes are degraded by starvation-induced and constitutive autophagy in tobacco BY-2 suspension-cultured cells. FRONTIERS IN PLANT SCIENCE 2014; 5:629. [PMID: 25477890 PMCID: PMC4235271 DOI: 10.3389/fpls.2014.00629] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/23/2014] [Indexed: 05/07/2023]
Abstract
Very recently, autophagy has been recognized as an important degradation pathway for quality control of peroxisomes in Arabidopsis plants. To further characterize the role of autophagy in plant peroxisome degradation, we generated stable transgenic suspension-cultured cell lines of heterotrophic Nicotiana tabacum L. cv. Bright Yellow 2 expressing a peroxisome-targeted version of enhanced yellow fluorescent protein. Indeed, this cell line model system proved advantageous for detailed cytological analyses of autophagy stages and for quantification of cellular peroxisome pools under different culturing conditions and upon inhibitor applications. Complementary biochemical, cytological, and pharmacological analyses provided convincing evidence for peroxisome degradation by bulk autophagy during carbohydrate starvation. This degradation was slowed down by the inhibitor of autophagy, 3-methyladenine (3-MA), but the 3-MA effect ceased at advanced stages of starvation, indicating that another degradation mechanism for peroxisomes might have taken over. 3-MA also caused an increase particularly in peroxisomal proteins and cellular peroxisome numbers when applied under nutrient-rich conditions in the logarithmic growth phase, suggesting a high turnover rate for peroxisomes by basal autophagy under non-stress conditions. Together, our data demonstrate that a great fraction of the peroxisome pool is subject to extensive autophagy-mediated turnover under both nutrient starvation and optimal growth conditions. Our analyses of the cellular pool size of peroxisomes provide a new tool for quantitative investigations of the role of plant peroxisomes in reactive oxygen species metabolism.
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Affiliation(s)
- Olga V. Voitsekhovskaja
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität GöttingenGöttingen, Germany
- Komarov Botanical Institute, Russian Academy of Sciences, Laboratory of Plant Ecological PhysiologySaint Petersburg, Russia
| | - Andreas Schiermeyer
- Abteilung Pflanzenbiotechnologie, Fraunhofer-Institut für Molekularbiologie und Angewandte OekologieAachen, Germany
| | - Sigrun Reumann
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität GöttingenGöttingen, Germany
- Institute for Mathematics and Natural Sciences, Faculty of Science and Technology, Centre for Organelle Research, University of StavangerStavanger, Norway
- Faculty of Mathematics, Informatics and Natural Sciences, Biocentre Klein Flottbek, University of HamburgHamburg, Germany
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42
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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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Hanamata S, Kurusu T, Kuchitsu K. Roles of autophagy in male reproductive development in plants. FRONTIERS IN PLANT SCIENCE 2014; 5:457. [PMID: 25309556 PMCID: PMC4163999 DOI: 10.3389/fpls.2014.00457] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 08/23/2014] [Indexed: 05/18/2023]
Abstract
Autophagy, a major catabolic pathway in eukaryotic cells, is essential in development, maintenance of cellular homeostasis, immunity and programmed cell death (PCD) in multicellular organisms. In plant cells, autophagy plays roles in recycling of proteins and metabolites including lipids, and is involved in many physiological processes such as abiotic and biotic stress responses. However, its roles during reproductive development had remained poorly understood. Quantitative live cell imaging techniques for the autophagic flux and genetic studies in several plant species have recently revealed significant roles of autophagy in developmental processes, regulation of PCD and lipid metabolism. We here review the novel roles of autophagic fluxes in plant cells, and discuss their possible significance in PCD and metabolic regulation, with particular focus on male reproductive development during the pollen maturation.
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Affiliation(s)
- Shigeru Hanamata
- Department of Applied Biological Science, Tokyo University of ScienceNoda, Japan
- Department of Integrated Biosciences, University of TokyoKashiwa, Japan
| | - Takamitsu Kurusu
- Department of Applied Biological Science, Tokyo University of ScienceNoda, Japan
- School of Bioscience and Biotechnology, Tokyo University of TechnologyHachioji, Japan
- Research Institute for Science and Technology, Tokyo University of ScienceNoda, Japan
| | - Kazuyuki Kuchitsu
- Department of Applied Biological Science, Tokyo University of ScienceNoda, Japan
- Research Institute for Science and Technology, Tokyo University of ScienceNoda, Japan
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Morita MT, Shimada T. The Plant Endomembrane System—A Complex Network Supporting Plant Development and Physiology. ACTA ACUST UNITED AC 2014; 55:667-71. [DOI: 10.1093/pcp/pcu049] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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