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Lizarrondo J, Wilfling F. Selective Autophagy of Macromolecular Complexes: What Does It Take to be Taken? J Mol Biol 2024:168574. [PMID: 38636617 DOI: 10.1016/j.jmb.2024.168574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 04/08/2024] [Accepted: 04/11/2024] [Indexed: 04/20/2024]
Abstract
Proteins are known to perform an astonishing array of functions thanks to their ability to cooperate and modulate each other's properties. Inside cells, proteins can assemble into large multi-subunit complexes to carry out complex cellular functions. The correct assembly and maintenance of the functional state of macromolecular protein complexes is crucial for human health. Failure to do so leads to loss of function and potential accumulation of harmful materials, which is associated with a variety of human diseases such as neurodegeneration and cancer. Autophagy engulfs cytosolic material in autophagosomes, and therefore is best suited to eliminate intact macromolecular complexes without disassembling them, which could interfere with de novo assembly. In this review, we discuss the role of autophagy in the selective degradation of macromolecular complexes. We highlight the current state of knowledge for different macromolecular complexes and their selective autophagic degradation. We emphasize the gaps in our understanding of what it takes for these large macromolecular complexes to be degraded and point to future work that may shed light on the regulation of the selective degradation of macromolecular complexes by autophagy.
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Affiliation(s)
- Javier Lizarrondo
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, Frankfurt a.M. 60598, Germany
| | - Florian Wilfling
- Mechanisms of Cellular Quality Control, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, Frankfurt a.M. 60438, Germany.
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2
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Cadena-Ramos AI, De-la-Peña C. Picky eaters: selective autophagy in plant cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:364-384. [PMID: 37864806 DOI: 10.1111/tpj.16508] [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: 07/14/2023] [Revised: 09/21/2023] [Accepted: 10/10/2023] [Indexed: 10/23/2023]
Abstract
Autophagy, a fundamental cellular process, plays a vital role in maintaining cellular homeostasis by degrading damaged or unnecessary components. While selective autophagy has been extensively studied in animal cells, its significance in plant cells has only recently gained attention. In this review, we delve into the intriguing realm selective autophagy in plants, with specific focus on its involvement in nutrient recycling, organelle turnover, and stress response. Moreover, recent studies have unveiled the interesting interplay between selective autophagy and epigenetic mechanisms in plants, elucidating the significance of epigenetic regulation in modulating autophagy-related gene expression and finely tuning the selective autophagy process in plants. By synthesizing existing knowledge, this review highlights the emerging field of selective autophagy in plant cells, emphasizing its pivotal role in maintaining nutrient homeostasis, facilitating cellular adaptation, and shedding light on the epigenetic regulation that governs these processes. Our comprehensive study provides the way for a deeper understanding of the dynamic control of cellular responses to nutrient availability and stress conditions, opening new avenues for future research in this field of autophagy in plant physiology.
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Affiliation(s)
- Alexis I Cadena-Ramos
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Calle 43 No. 130 x 32 y 34 Col. Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
| | - Clelia De-la-Peña
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Calle 43 No. 130 x 32 y 34 Col. Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
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3
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Sun Y, Li J, Zhang L, Lin R. Regulation of chloroplast protein degradation. J Genet Genomics 2023:S1673-8527(23)00049-8. [PMID: 36863685 DOI: 10.1016/j.jgg.2023.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/02/2023] [Accepted: 02/14/2023] [Indexed: 03/04/2023]
Abstract
Chloroplasts are unique organelles that not only provide sites for photosynthesis and many metabolic processes, but also are sensitive to various environmental stresses. Chloroplast proteins are encoded by genes from both nuclear and chloroplast genomes. During chloroplast development and responses to stresses, the robust protein quality control systems are essential for regulation of protein homeostasis and the integrity of chloroplast proteome. In this review, we summarize the regulatory mechanisms of chloroplast protein degradation refer to protease system, ubiquitin-proteasome system, and the chloroplast autophagy. These mechanisms symbiotically play a vital role in chloroplast development and photosynthesis under both normal or stress conditions.
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Affiliation(s)
- Yang Sun
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, Henan 475001, China
| | - Jialong Li
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, Henan 475001, China.
| | - Rongcheng Lin
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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4
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Research progress on maintaining chloroplast homeostasis under stress conditions: a review. Acta Biochim Biophys Sin (Shanghai) 2023; 55:173-182. [PMID: 36840466 PMCID: PMC10157539 DOI: 10.3724/abbs.2023022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
On a global scale, drought, salinity, extreme temperature, and other abiotic stressors severely limit the quality and yield of crops. Therefore, it is crucial to clarify the adaptation strategies of plants to harsh environments. Chloroplasts are important environmental sensors in plant cells. For plants to thrive in different habitats, chloroplast homeostasis must be strictly regulated, which is necessary to maintain efficient plant photosynthesis and other metabolic reactions under stressful environments. To maintain normal chloroplast physiology, two important biological processes are needed: the import and degradation of chloroplast proteins. The orderly import of chloroplast proteins and the timely degradation of damaged chloroplast components play a key role in adapting plants to their environment. In this review, we briefly described the mechanism of chloroplast TOC-TIC protein transport. The importance and recent progress of chloroplast protein turnover, retrograde signaling, and chloroplast protein degradation under stress are summarized. Furthermore, the potential of targeted regulation of chloroplast homeostasis is emphasized to improve plant adaptation to environmental stresses.
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5
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Yanagisawa M, Chuong SDX. Chloroplast Envelopes Play a Role in the Formation of Autophagy-Related Structures in Plants. PLANTS (BASEL, SWITZERLAND) 2023; 12:443. [PMID: 36771525 PMCID: PMC9920391 DOI: 10.3390/plants12030443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Autophagy is a degradation process of cytoplasmic components that is conserved in eukaryotes. One of the hallmark features of autophagy is the formation of double-membrane structures known as autophagosomes, which enclose cytoplasmic content destined for degradation. Although the membrane source for the formation of autophagosomes remains to be determined, recent studies indicate the involvement of various organelles in autophagosome biogenesis. In this study, we examined the autophagy process in Bienertia sinuspersici: one of four terrestrial plants capable of performing C4 photosynthesis in a single cell (single-cell C4 species). We demonstrated that narrow tubules (stromule-like structures) 30-50 nm in diameter appear to extend from chloroplasts to form the membrane-bound structures (autophagosomes or autophagy-related structures) in chlorenchyma cells of B. sinuspersici during senescence and under oxidative stress. Immunoelectron microscopic analysis revealed the localization of stromal proteins to the stromule-like structures, sequestering portions of the cytoplasm in chlorenchyma cells of oxidative stress-treated leaves of B. sinuspersici and Arabidopsis thaliana. Moreover, the fluorescent marker for autophagosomes GFP-ATG8, colocalized with the autophagic vacuole maker neutral red in punctate structures in close proximity to the chloroplasts of cells under oxidative stress conditions. Together our results implicate a role for chloroplast envelopes in the autophagy process induced during senescence or under certain stress conditions in plants.
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6
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Autophagic degradation of membrane-bound organelles in plants. Biosci Rep 2023; 43:232379. [PMID: 36562332 PMCID: PMC9842949 DOI: 10.1042/bsr20221204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/19/2022] [Accepted: 12/22/2022] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic cells have evolved membrane-bound organelles, including the endoplasmic reticulum (ER), Golgi, mitochondria, peroxisomes, chloroplasts (in plants and green algae) and lysosomes/vacuoles, for specialized functions. Organelle quality control and their proper interactions are crucial both for normal cell homeostasis and function and for environmental adaption. Dynamic turnover of organelles is tightly controlled, with autophagy playing an essential role. Autophagy is a programmed process for efficient clearing of unwanted or damaged macromolecules or organelles, transporting them to vacuoles for degradation and recycling and thereby enhancing plant environmental plasticity. The specific autophagic engulfment of organelles requires activation of a selective autophagy pathway, recognition of the organelle by a receptor, and selective incorporation of the organelle into autophagosomes. While some of the autophagy machinery and mechanisms for autophagic removal of organelles is conserved across eukaryotes, plants have also developed unique mechanisms and machinery for these pathways. In this review, we discuss recent progress in understanding autophagy regulation in plants, with a focus on autophagic degradation of membrane-bound organelles. We also raise some important outstanding questions to be addressed in the future.
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7
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Luong AM, Koestel J, Bhati KK, Batoko H. Cargo receptors and adaptors for selective autophagy in plant cells. FEBS Lett 2022; 596:2104-2132. [PMID: 35638898 DOI: 10.1002/1873-3468.14412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/08/2022] [Accepted: 05/23/2022] [Indexed: 11/06/2022]
Abstract
Plant selective (macro)autophagy is a highly regulated process whereby eukaryotic cells spatiotemporally degrade some of their constituents that have become superfluous or harmful. The identification and characterization of the factors determining this selectivity make it possible to integrate selective (macro)autophagy into plant cell physiology and homeostasis. The specific cargo receptors and/or scaffold proteins involved in this pathway are generally not structurally conserved, as are the biochemical mechanisms underlying recognition and integration of a given cargo into the autophagosome in different cell types. This review discusses the few specific cargo receptors described in plant cells to highlight key features of selective autophagy in the plant kingdom and its integration with plant physiology, so as to identify evolutionary convergence and knowledge gaps to be filled by future research.
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Affiliation(s)
- Ai My Luong
- Louvain Institute of Biomolecular Science and Technology, University of Louvain Croix du Sud 4, L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Jérôme Koestel
- Louvain Institute of Biomolecular Science and Technology, University of Louvain Croix du Sud 4, L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Kaushal Kumar Bhati
- Louvain Institute of Biomolecular Science and Technology, University of Louvain Croix du Sud 4, L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Henri Batoko
- Louvain Institute of Biomolecular Science and Technology, University of Louvain Croix du Sud 4, L7.07.14, 1348, Louvain-la-Neuve, Belgium
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8
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Shedding Light on the Role of Phosphorylation in Plant Autophagy. FEBS Lett 2022; 596:2172-2185. [DOI: 10.1002/1873-3468.14352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/30/2022] [Accepted: 04/04/2022] [Indexed: 11/07/2022]
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9
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Shen J, Chen Q, Li Z, Zheng Q, Xu Y, Zhou H, Mao H, Shen Q, Liu P. Proteomic and metabolomic analysis of Nicotiana benthamiana under dark stress. FEBS Open Bio 2022; 12:231-249. [PMID: 34792288 PMCID: PMC8727940 DOI: 10.1002/2211-5463.13331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 10/15/2021] [Accepted: 11/13/2021] [Indexed: 11/08/2022] Open
Abstract
Exposure to extended periods of darkness is a common source of abiotic stress that significantly affects plant growth and development. To understand how Nicotiana benthamiana responds to dark stress, the proteomes and metabolomes of leaves treated with darkness were studied. In total, 5763 proteins and 165 primary metabolites were identified following dark treatment. Additionally, the expression of autophagy-related gene (ATG) proteins was transiently upregulated. Weighted gene coexpression network analysis (WGCNA) was utilized to find the protein modules associated with the response to dark stress. A total of four coexpression modules were obtained. The results indicated that heat-shock protein (HSP70), SnRK1-interacting protein 1, 2A phosphatase-associated protein of 46 kDa (Tap46), and glutamate dehydrogenase (GDH) might play crucial roles in N. benthamiana's response to dark stress. Furthermore, a protein-protein interaction (PPI) network was constructed and top-degreed proteins were predicted to identify potential key factors in the response to dark stress. These proteins include isopropylmalate isomerase (IPMI), eukaryotic elongation factor 5A (ELF5A), and ribosomal protein 5A (RPS5A). Finally, metabolic analysis suggested that some amino acids and sugars were involved in the dark-responsive pathways. Thus, these results provide a new avenue for understanding the defensive mechanism against dark stress at the protein and metabolic levels in N. benthamiana.
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Affiliation(s)
- Juan‐Juan Shen
- College of ChemistryZhengzhou UniversityZhengzhouChina
- Chemistry Research Institution of Henan Academy of SciencesZhengzhouChina
| | - Qian‐Si Chen
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Ze‐Feng Li
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Qing‐Xia Zheng
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Ya‐Long Xu
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Hui‐Na Zhou
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
| | - Hong‐Yan Mao
- College of ChemistryZhengzhou UniversityZhengzhouChina
| | - Qi Shen
- College of ChemistryZhengzhou UniversityZhengzhouChina
| | - Ping‐Ping Liu
- Zhengzhou Tobacco Research Institute of CNTCZhengzhouChina
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10
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Arabidopsis PII Proteins Form Characteristic Foci in Chloroplasts Indicating Novel Properties in Protein Interaction and Degradation. Int J Mol Sci 2021; 22:ijms222312666. [PMID: 34884470 PMCID: PMC8657445 DOI: 10.3390/ijms222312666] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 11/16/2021] [Accepted: 11/21/2021] [Indexed: 11/16/2022] Open
Abstract
The PII protein is an evolutionary, highly conserved regulatory protein found in both bacteria and higher plants. In bacteria, it modulates the activity of several enzymes, transporters, and regulatory factors by interacting with them and thereby regulating important metabolic hubs, such as carbon/nitrogen homeostasis. More than two decades ago, the PII protein was characterized for the first time in plants, but its physiological role is still not sufficiently resolved. To gain more insights into the function of this protein, we investigated the interaction behavior of AtPII with candidate proteins by BiFC and FRET/FLIM in planta and with GFP/RFP traps in vitro. In the course of these studies, we found that AtPII interacts in chloroplasts with itself as well as with known interactors such as N-acetyl-L-glutamate kinase (NAGK) in dot-like aggregates, which we named PII foci. In these novel protein aggregates, AtPII also interacts with yet unknown partners, which are known to be involved in plastidic protein degradation. Further studies revealed that the C-terminal component of AtPII is crucial for the formation of PII foci. Altogether, the discovery and description of PII foci indicate a novel mode of interaction between PII proteins and other proteins in plants. These findings may represent a new starting point for the elucidation of physiological functions of PII proteins in plants.
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11
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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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12
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Nakamura S, Hagihara S, Izumi M. Mitophagy in plants. Biochim Biophys Acta Gen Subj 2021; 1865:129916. [PMID: 33932484 DOI: 10.1016/j.bbagen.2021.129916] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/06/2021] [Accepted: 04/26/2021] [Indexed: 12/11/2022]
Abstract
Mitochondria play a central role in primary metabolism in plants as well as in heterotrophic eukaryotes. Plants must control the quality and number of mitochondria in response to a changing environment, across cell types and developmental stages. Mitophagy is defined as the degradation of mitochondria by autophagy, an evolutionarily conserved system for the removal and recycling of intracellular components. Recent studies have highlighted the importance of mitophagy in plant stress responses. This review article summarizes our current knowledge of plant mitophagy and discusses the underlying mechanisms. In plants, chloroplasts cooperate with mitochondria for energy production, and autophagy also targets chloroplasts through a process known as chlorophagy. Advances in plant autophagy studies now allow a comparative analysis of the autophagic turnover of mitochondria and chloroplasts, via the selective degradation of their soluble proteins, fragments, or entire organelles.
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Affiliation(s)
- Sakuya Nakamura
- Center for Sustainable Resource Science (CSRS), RIKEN, 351-0198 Wako, Japan
| | - Shinya Hagihara
- Center for Sustainable Resource Science (CSRS), RIKEN, 351-0198 Wako, Japan
| | - Masanori Izumi
- Center for Sustainable Resource Science (CSRS), RIKEN, 351-0198 Wako, Japan.
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13
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Alomrani S, Kunert KJ, Foyer CH. Papain-like cysteine proteases are required for the regulation of photosynthetic gene expression and acclimation to high light stress. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3441-3454. [PMID: 33686435 PMCID: PMC8256631 DOI: 10.1093/jxb/erab101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 03/01/2021] [Indexed: 05/24/2023]
Abstract
Chloroplasts are considered to be devoid of cysteine proteases. Using transgenic Arabidopsis lines expressing the rice cystatin, oryzacystatin I (OC-I), in the chloroplasts (PC lines) or cytosol (CYS lines), we explored the hypothesis that cysteine proteases regulate photosynthesis. The CYS and PC lines flowered later than the wild type (WT) and accumulated more biomass after flowering. In contrast to the PC rosettes, which accumulated more leaf chlorophyll and carotenoid pigments than the WT, the CYS lines had lower amounts of leaf pigments. High-light-dependent decreases in photosynthetic carbon assimilation and the abundance of the Rubisco large subunit protein, the D1 protein, and the phosphorylated form of D1 proteins were attenuated in the CYS lines and reversed in the PC lines relative to the WT. However, the transgenic lines had higher amounts of LHC, rbcs, pasbA, and pasbD transcripts than the WT, and also showed modified chloroplast to nucleus signalling. We conclude that cysteine proteases accelerate the reconfiguration of the chloroplast proteome after flowering and in response to high-light stress. Inhibition of cysteine proteases, such as AtCEP1, slows chloroplast protein degradation and stimulates photosynthetic gene expression and chloroplast to nucleus signalling, enhancing stress tolerance traits.
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Affiliation(s)
- Sarah Alomrani
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Karl J Kunert
- Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Christine H Foyer
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
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14
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Yoshitake Y, Nakamura S, Shinozaki D, Izumi M, Yoshimoto K, Ohta H, Shimojima M. RCB-mediated chlorophagy caused by oversupply of nitrogen suppresses phosphate-starvation stress in plants. PLANT PHYSIOLOGY 2021; 185:318-330. [PMID: 33721901 PMCID: PMC8133631 DOI: 10.1093/plphys/kiaa030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 10/28/2020] [Indexed: 05/26/2023]
Abstract
Inorganic phosphate (Pi) and nitrogen (N) are essential nutrients for plant growth. We found that a five-fold oversupply of nitrate rescues Arabidopsis (Arabidopsis thaliana) plants from Pi-starvation stress. Analyses of transgenic plants that overexpressed GFP-AUTOPHAGY8 showed that an oversupply of nitrate induced autophagy flux under Pi-depleted conditions. Expression of DIN6 and DIN10, the carbon (C) starvation-responsive genes, was upregulated when nitrate was oversupplied under Pi starvation, which suggested that the plants recognized the oversupply of nitrate as C starvation stress because of the reduction in the C/N ratio. Indeed, formation of Rubisco-containing bodies (RCBs), which contain chloroplast stroma and are induced by C starvation, was enhanced when nitrate was oversupplied under Pi starvation. Moreover, autophagy-deficient mutants did not release Pi (unlike wild-type plants), exhibited no RCB accumulation inside vacuoles, and were hypersensitive to Pi starvation, indicating that RCB-mediated chlorophagy is involved in Pi starvation tolerance. Thus, our results showed that the Arabidopsis response to Pi starvation is closely linked with N and C availability and that autophagy is a key factor that controls plant growth under Pi starvation.
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Affiliation(s)
- Yushi Yoshitake
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8501, Japan
- Department of Life Science, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
| | - Sakuya Nakamura
- Center for Sustainable Resource Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Daiki Shinozaki
- Department of Life Science, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
- Life Science Program, Graduate School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
| | - Masanori Izumi
- Center for Sustainable Resource Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Kohki Yoshimoto
- Department of Life Science, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
- Life Science Program, Graduate School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
| | - Hiroyuki Ohta
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8501, Japan
| | - Mie Shimojima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8501, Japan
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15
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Sandhu N, Sethi M, Kumar A, Dang D, Singh J, Chhuneja P. Biochemical and Genetic Approaches Improving Nitrogen Use Efficiency in Cereal Crops: A Review. FRONTIERS IN PLANT SCIENCE 2021; 12:657629. [PMID: 34149755 PMCID: PMC8213353 DOI: 10.3389/fpls.2021.657629] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 04/06/2021] [Indexed: 05/22/2023]
Abstract
Nitrogen is an essential nutrient required in large quantities for the proper growth and development of plants. Nitrogen is the most limiting macronutrient for crop production in most of the world's agricultural areas. The dynamic nature of nitrogen and its tendency to lose soil and environment systems create a unique and challenging environment for its proper management. Exploiting genetic diversity, developing nutrient efficient novel varieties with better agronomy and crop management practices combined with improved crop genetics have been significant factors behind increased crop production. In this review, we highlight the various biochemical, genetic factors and the regulatory mechanisms controlling the plant nitrogen economy necessary for reducing fertilizer cost and improving nitrogen use efficiency while maintaining an acceptable grain yield.
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Ma D, Endo S, Betsuyaku S, Shimotohno A, Fukuda H. CLE2 regulates light-dependent carbohydrate metabolism in Arabidopsis shoots. PLANT MOLECULAR BIOLOGY 2020; 104:561-574. [PMID: 32980951 DOI: 10.1007/s11103-020-01059-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 08/21/2020] [Indexed: 05/05/2023]
Abstract
This study focused on the role of CLE1-CLE7 peptides as environmental mediators and indicated that root-induced CLE2 functions systemically in light-dependent carbohydrate metabolism in shoots. Plants sense environmental stimuli and convert them into cellular signals, which are transmitted to distinct cells and tissues to induce adequate responses. Plant hormones and small secretory peptides often function as environmental stress mediators. In this study, we investigated whether CLAVATA3/EMBRYO SURROUNDING REGION-RELATED proteins, CLE1-CLE7, which share closely related CLE domains, mediate environmental stimuli in Arabidopsis thaliana. Expression analysis of CLE1-CLE7 revealed that these genes respond to different environmental stimuli, such as nitrogen deprivation, nitrogen replenishment, cold, salt, dark, and sugar starvation, in a sophisticated manner. To further investigate the function of CLE2, we generated transgenic Arabidopsis lines expressing the β-glucuronidase gene under the control of the CLE2 promoter or expressing the CLE2 gene under the control of an estradiol-inducible promoter. We also generated cle2-1 and cle2-2 mutants using the CRISPR/Cas9 technology. In these transgenic lines, dark induced the expression of CLE2 in the root vasculature. Additionally, induction of CLE2 in roots induced the expression of various genes not only in roots but also in shoots, and genes related to light-dependent carbohydrate metabolism were particularly induced in shoots. In addition, cle2 mutant plants showed chlorosis when subjected to a shade treatment. These results suggest that root-induced CLE2 functions systemically in light-dependent carbohydrate metabolism in shoots.
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Affiliation(s)
- Dichao Ma
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Satoshi Endo
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shigeyuki Betsuyaku
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
- Microbiology Research Center for Sustainability, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
| | - Akie Shimotohno
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hiroo Fukuda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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17
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Wijerathna-Yapa A, Stroeher E, Fenske R, Li L, Duncan O, Millar AH. Proteomics for Autophagy Receptor and Cargo Identification in Plants. J Proteome Res 2020; 20:129-138. [PMID: 33241938 DOI: 10.1021/acs.jproteome.0c00609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Autophagy is a catabolic process facilitating the degradation of cytoplasmic proteins and organelles in a lysosome- or vacuole-dependent manner in plants, animals, and fungi. Proteomic studies have demonstrated that autophagy controls and shapes the proteome and has identified both receptor and cargo proteins inside autophagosomes. In a smaller selection of studies, proteomics has been used for the analysis of post-translational modifications that target proteins for elimination and protein-protein interactions between receptors and cargo, providing a better understanding of the complex regulatory processes controlling autophagy. In this perspective, we highlight how proteomic studies have contributed to our understanding of autophagy in plants against the backdrop of yeast and animal studies. We then provide a framework for how the future application of proteomics in plant autophagy can uncover the mechanisms and outcomes of sculpting organelles during plant development, particularly through the identification of autophagy receptors and cargo in plants.
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Affiliation(s)
- Akila Wijerathna-Yapa
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, 6009 Crawley, Western Australia, Australia
| | - Elke Stroeher
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, 6009 Crawley, Western Australia, Australia
| | - Ricarda Fenske
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, 6009 Crawley, Western Australia, Australia
| | - Lei Li
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, 6009 Crawley, Western Australia, Australia.,Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, 300071 Tianjin, China
| | - Owen Duncan
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, 6009 Crawley, Western Australia, Australia
| | - A Harvey Millar
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, 6009 Crawley, Western Australia, Australia
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18
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Dündar G, Teranishi M, Hidema J. Autophagy-deficient Arabidopsis mutant atg5, which shows ultraviolet-B sensitivity, cannot remove ultraviolet-B-induced fragmented mitochondria. Photochem Photobiol Sci 2020; 19:1717-1729. [PMID: 33237047 DOI: 10.1039/c9pp00479c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mitochondria damaged by ultraviolet-B radiation (UV-B, 280-315 nm) are removed by mitophagy, a selective autophagic process. Recently, we demonstrated that autophagy-deficient Arabidopsis thaliana mutants exhibit a UV-B-sensitive phenotype like that of cyclobutane pyrimidine dimer (CPD)-specific photolyase (PHR1)-deficient mutants. To explore the relationship between UV-B sensitivity and autophagy in UV-B-damaged plants, we monitored mitochondrial dynamics and autophagy in wild-type Arabidopsis (ecotype Columbia); an autophagy-deficient mutant, atg5; a PHR1-deficient mutant, phr1; an atg5 phr1 double mutant; and AtPHR1-overexpressing (AtPHR1ox) plants following high-dose UV-B exposure (1.5 W m-2 for 1 h). At 10 h after exposure, the number of mitochondria per mesophyll leaf cell was increased and the volumes of individual mitochondria were decreased independently of UV-B-induced CPD accumulation in all genotypes. At 24 h after exposure, the mitochondrial number had recovered or almost recovered to pre-exposure levels in plants with functional autophagy (WT, phr1, and AtPHR1ox), but had increased even further in atg5. This suggested that the high dose of UV-B led to the inactivation and fragmentation of mitochondria, which were removed by mitophagy activated by UV-B. The UV-B-sensitive phenotype of the atg5 phr1 double mutant was more severe than that of atg5 or phr1. In wild-type, phr1, and AtPHR1ox plants, autophagy-related genes were strongly expressed following UV-B exposure independently of UV-B-induced CPD accumulation. Therefore, mitophagy might be one of the important repair mechanisms for UV-B-induced damage. The severe UV-B-sensitive phenotype of atg5 phr1 is likely an additive effect of deficiencies in independent machineries for UV-B protection, autophagy, and CPD photorepair.
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Affiliation(s)
- Gönül Dündar
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
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19
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High-throughput sequencing reveals the molecular mechanisms determining the stay-green characteristic in soybeans. J Biosci 2020. [DOI: 10.1007/s12038-020-00074-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Li S, Yan H, Mei WM, Tse YC, Wang H. Boosting autophagy in sexual reproduction: a plant perspective. THE NEW PHYTOLOGIST 2020; 226:679-689. [PMID: 31917864 DOI: 10.1111/nph.16414] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/21/2019] [Indexed: 06/10/2023]
Abstract
The key process of sexual reproduction is the successful fusion of the sperm and egg cell. Distinct from dynamic and flagellated animal sperm cells, higher flowering plant sperm cells are immotile. Therefore, plants have evolved a novel reproductive system to achieve fertilization and generate progenies. Plant sexual reproduction consists of multiple steps, mainly including gametophyte development, pollen-pistil recognition, pollen germination, double fertilization and postfertilization. During reproduction, active production, consumption and recycling of cellular components and energy are critically required to achieve fertilization. However, the underlying machinery of cellular degradation and turnover remains largely unexplored. Autophagy, the major catabolic pathway in eukaryotic cells, participates in regulating multiple aspects of plant activities, including abiotic and biotic stress resistance, pathogen response, senescence, nutrient remobilization and plant development. Nevertheless, a key unanswered question is how autophagy regulates plant fertilization and reproduction. Here, we focus on comparing and contrasting autophagy in several key reproductive processes of plant and animal systems to feature important distinctions and highlight future research directions of autophagy in angiosperm reproduction. We further discuss the potential crosstalk between autophagy and programmed cell death, which are often considered as two disconnected events in plant sexual reproduction.
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Affiliation(s)
- Shanshan Li
- College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - He Yan
- College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Wei-Ming Mei
- Outpatient Department of Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510275, China
| | - Yu Chung Tse
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment and Department of Biology, Southern University of Science and Technology, Shenzhen, 518005, China
| | - Hao Wang
- College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China
- Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, 510642, China
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21
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Yamashita H, Kambe Y, Ohshio M, Kunihiro A, Tanaka Y, Suzuki T, Nakamura Y, Morita A, Ikka T. Integrated Metabolome and Transcriptome Analyses Reveal Etiolation-Induced Metabolic Changes Leading to High Amino Acid Contents in a Light-Sensitive Japanese Albino Tea Cultivar. FRONTIERS IN PLANT SCIENCE 2020; 11:611140. [PMID: 33537046 PMCID: PMC7847902 DOI: 10.3389/fpls.2020.611140] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/15/2020] [Indexed: 05/16/2023]
Abstract
Plant albinism causes the etiolation of leaves because of factors such as deficiency of chloroplasts or chlorophylls. In general, albino tea leaves accumulate higher free amino acid (FAA) contents than do conventional green tea leaves. To explore the metabolic changes of etiolated leaves (EL) in the light-sensitive Japanese albino tea cultivar "Koganemidori," we performed integrated metabolome and transcriptome analyses by comparing EL with green leaves induced by bud-sport mutation (BM) or shading treatments (S-EL). Comparative omics analyses indicated that etiolation-induced molecular responses were independent of the light environment and were largely influenced by the etiolation itself. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and pathway analyses revealed the downregulation of genes involved in chloroplast development and chlorophyll biosynthesis and upregulation of protein degradation-related pathways, such as the ubiquitin-proteasome system and autophagy in EL. Metabolome analysis showed that most quantified FAAs in EL were highly accumulated compared with those in BM and S-EL. Genes involved in the tricarboxylic acid (TCA) cycle, nitrogen assimilation, and the urea cycle, including the drastically downregulated Arginase-1 homolog, which functions in nitrogen excretion for recycling, showed lower expression levels in EL. The high FAA contents in EL might result from the increased FAA pool and nitrogen source contributed by protein degradation, low N consumption, and stagnation of the urea cycle rather than through enhanced amino acid biosynthesis.
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Affiliation(s)
- Hiroto Yamashita
- Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
- United Graduate School of Agricultural Science, Gifu University, Gifu, Japan
| | - Yuka Kambe
- Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
| | - Megumi Ohshio
- Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
| | - Aya Kunihiro
- Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
| | - Yasuno Tanaka
- Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
- United Graduate School of Agricultural Science, Gifu University, Gifu, Japan
| | - Toshikazu Suzuki
- Tea Research Center, Shizuoka Prefectural Research Institute of Agriculture and Forestry, Shizuoka, Japan
| | - Yoriyuki Nakamura
- Graduate Division of Nutritional and Environmental Science, Tea Science Center, University of Shizuoka, Shizuoka, Japan
| | - Akio Morita
- Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
- Institute for Tea Science, Shizuoka University, Shizuoka, Japan
| | - Takashi Ikka
- Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
- Institute for Tea Science, Shizuoka University, Shizuoka, Japan
- *Correspondence: Takashi Ikka,
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22
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Frank S, Hollmann J, Mulisch M, Matros A, Carrión CC, Mock HP, Hensel G, Krupinska K. Barley cysteine protease PAP14 plays a role in degradation of chloroplast proteins. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6057-6069. [PMID: 31403664 PMCID: PMC6859807 DOI: 10.1093/jxb/erz356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 07/31/2019] [Indexed: 05/18/2023]
Abstract
Chloroplast protein degradation is known to occur both inside chloroplasts and in the vacuole. Genes encoding cysteine proteases have been found to be highly expressed during leaf senescence. However, it remains unclear where they participate in chloroplast protein degradation. In this study HvPAP14, which belongs to the C1A family of cysteine proteases, was identified in senescing barley (Hordeum vulgare L.) leaves by affinity enrichment using the mechanism-based probe DCG-04 targeting cysteine proteases and subsequent mass spectrometry. Biochemical analyses and expression of a HvPAP14:RFP fusion construct in barley protoplasts was used to identify the subcellular localization and putative substrates of HvPAP14. The HvPAP14:RFP fusion protein was detected in the endoplasmic reticulum and in vesicular bodies. Immunological studies showed that HvPAP14 was mainly located in chloroplasts, where it was found in tight association with thylakoid membranes. The recombinant enzyme was activated by low pH, in accordance with the detection of HvPAP14 in the thylakoid lumen. Overexpression of HvPAP14 in barley revealed that the protease can cleave LHCB proteins and PSBO as well as the large subunit of Rubisco. HvPAP14 is involved in the normal turnover of chloroplast proteins and may have a function in bulk protein degradation during leaf senescence.
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Affiliation(s)
- Susann Frank
- Institute of Botany, Christian-Albrechts-University of Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Julien Hollmann
- Institute of Botany, Christian-Albrechts-University of Kiel, Olshausenstraße 40, 24098 Kiel, Germany
- Solana Research, Eichenallee 9, Windeby, Germany
| | - Maria Mulisch
- Institute of Botany, Christian-Albrechts-University of Kiel, Olshausenstraße 40, 24098 Kiel, Germany
- Central Microscopy, Christian-Albrechts-University of Kiel, Olshausenstraße 40, Kiel, Germany
| | - Andrea Matros
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, Seeland, OT Gatersleben, Germany
| | - Cristian C Carrión
- Instituto de Fisiología Vegetal, INFIVE, CONICET-UNLP, cc 327, 1900 La Plata, Argentina
| | - Hans-Peter Mock
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, Seeland, OT Gatersleben, Germany
| | - Götz Hensel
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, Seeland, OT Gatersleben, Germany
| | - Karin Krupinska
- Institute of Botany, Christian-Albrechts-University of Kiel, Olshausenstraße 40, 24098 Kiel, Germany
- Correspondence:
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23
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Trupkin SA, Astigueta FH, Baigorria AH, García MN, Delfosse VC, González SA, Pérez de la Torre MC, Moschen S, Lía VV, Fernández P, Heinz RA. Identification and expression analysis of NAC transcription factors potentially involved in leaf and petal senescence in Petunia hybrida. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 287:110195. [PMID: 31481223 DOI: 10.1016/j.plantsci.2019.110195] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/17/2019] [Accepted: 07/19/2019] [Indexed: 05/23/2023]
Abstract
Progression of leaf senescence depends on several families of transcription factors. In Arabidopsis, the NAC family plays crucial roles in the modulation of leaf senescence; however, the mechanisms involved in this NAC-mediated regulation have not been extensively explored in agronomic species. Petunia hybrida is an ornamental plant that is commonly found worldwide. Decreasing the rate of leaf and petal senescence in P. hybrida is essential for maintaining plant quality. In this study, we examined the NAC-mediated networks involved in regulating senescence in this species. From 41 NAC genes, the expression of which changed in Arabidopsis during leaf senescence, we identified 29 putative orthologs in P. hybrida. Analysis using quantitative real-time-PCR indicated that 24 genes in P. hybrida changed their transcript levels during natural leaf senescence. Leaf-expressed genes were subsequently assessed in petals undergoing natural and pollination-induced senescence. Expression data and phylogenetic analysis were used to generate a list of 10-15 candidate genes; 7 of these were considered key regulatory candidates in senescence because of their consistent upregulation in the three senescence processes examined. Altogether, we identified common and distinct patterns of gene expression at different stages of leaf and petal development and during progression of senescence. The results obtained in this study will contribute to the understanding of NAC-mediated regulatory networks in petunia.
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Affiliation(s)
- Santiago A Trupkin
- Instituto de Floricultura, Centro de Investigación de Recursos Naturales, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina
| | - Francisco H Astigueta
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Amilcar H Baigorria
- Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Martín N García
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo - INTA-CONICET), Centro de Investigaciones en Ciencias Agronómicas y Veterinarias, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires, Argentina
| | - Verónica C Delfosse
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Sergio A González
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina
| | - Mariana Cecilia Pérez de la Torre
- Instituto de Floricultura, Centro de Investigación de Recursos Naturales, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires, Argentina
| | - Sebastián Moschen
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina
| | - Verónica V Lía
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo - INTA-CONICET), Centro de Investigaciones en Ciencias Agronómicas y Veterinarias, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Paula Fernández
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo - INTA-CONICET), Centro de Investigaciones en Ciencias Agronómicas y Veterinarias, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina.
| | - Ruth A Heinz
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo - INTA-CONICET), Centro de Investigaciones en Ciencias Agronómicas y Veterinarias, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
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24
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Gandullo J, Monreal JA, Álvarez R, Díaz I, García-Mauriño S, Echevarría C. Anionic Phospholipids Induce Conformational Changes in Phosphoenolpyruvate Carboxylase to Increase Sensitivity to Cathepsin Proteases. FRONTIERS IN PLANT SCIENCE 2019; 10:582. [PMID: 31143196 PMCID: PMC6521631 DOI: 10.3389/fpls.2019.00582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 04/18/2019] [Indexed: 06/09/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC) is a cytosolic, homotetrameric enzyme that serves a variety of functions in plants, acting as the primary form of CO2 fixation in the C4 photosynthesis pathway (C4-PEPC). In a previous work we have shown that C4-PEPC bind anionic phospholipids, resulting in PEPC inactivation. Also, we showed that PEPC can associate with membranes and to be partially proteolyzed. However, the mechanism controlling this remains unknown. Using semi purified-PEPC from sorghum leaf and a panel of PEPC-specific antibodies, we analyzed the conformational changes in PEPC induced by anionic phospholipids to cause the inactivation of the enzyme. Conformational changes observed involved the exposure of the C-terminus of PEPC from the native, active enzyme conformation. Investigation of the protease activity associated with PEPC demonstrated that cysteine proteases co-purify with the enzyme, with protease-specific substrates revealing cathepsin B and L as the major protease species present. The anionic phospholipid-induced C-terminal exposed conformation of PEPC appeared highly sensitive to the identified cathepsin protease activity and showed initial proteolysis of the enzyme beginning at the N-terminus. Taken together, these data provide the first evidence that anionic phospholipids promote not only the inactivation of the PEPC enzyme, but also its proteolysis.
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Affiliation(s)
- Jacinto Gandullo
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - José-Antonio Monreal
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Rosario Álvarez
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Isabel Díaz
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, Madrid, Spain
| | - Sofía García-Mauriño
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Cristina Echevarría
- Departamento de Biología Vegetal, Facultad de Biología, Universidad de Sevilla, Seville, Spain
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25
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Izumi M, Nakamura S, Li N. Autophagic Turnover of Chloroplasts: Its Roles and Regulatory Mechanisms in Response to Sugar Starvation. FRONTIERS IN PLANT SCIENCE 2019; 10:280. [PMID: 30967883 PMCID: PMC6439420 DOI: 10.3389/fpls.2019.00280] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 02/20/2019] [Indexed: 05/29/2023]
Abstract
Photosynthetic reactions in chloroplasts convert atmospheric carbon dioxide into starch and soluble sugars during the day. Starch, a transient storage form of sugar, is broken down into sugars as a source for respiratory energy production at night. Chloroplasts thus serve as the main sites of sugar production for photoautotrophic plant growth. Autophagy is an evolutionarily conserved intracellular process in eukaryotes that degrades organelles and proteins. Numerous studies have shown that autophagy is actively induced in sugar-starved plants. When photosynthetic sugar production is inhibited by environmental cues, chloroplasts themselves may become an attractive alternative energy source to sugars via their degradation. Here, we summarize the process of autophagic turnover of chloroplasts and its roles in plants in response to sugar starvation. We hypothesize that piecemeal-type chloroplast autophagy is specifically activated in plants in response to sugar starvation.
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Affiliation(s)
- Masanori Izumi
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Sakuya Nakamura
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Nan Li
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
- College of Life Sciences, Liaocheng University, Liaocheng, China
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26
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Young PG, Passalacqua MJ, Chappell K, Llinas RJ, Bartel B. A facile forward-genetic screen for Arabidopsis autophagy mutants reveals twenty-one loss-of-function mutations disrupting six ATG genes. Autophagy 2019; 15:941-959. [PMID: 30734619 PMCID: PMC6526838 DOI: 10.1080/15548627.2019.1569915] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Macroautophagy is a process through which eukaryotic cells degrade large substrates including organelles, protein aggregates, and invading pathogens. Over 40 autophagy-related (ATG) genes have been identified through forward-genetic screens in yeast. Although homology-based analyses have identified conserved ATG genes in plants, only a few atg mutants have emerged from forward-genetic screens in Arabidopsis thaliana. We developed a screen that consistently recovers Arabidopsis atg mutations by exploiting mutants with defective LON2/At5g47040, a protease implicated in peroxisomal quality control. Arabidopsis lon2 mutants exhibit reduced responsiveness to the peroxisomally-metabolized auxin precursor indole-3-butyric acid (IBA), heightened degradation of several peroxisomal matrix proteins, and impaired processing of proteins harboring N-terminal peroxisomal targeting signals; these defects are ameliorated by preventing autophagy. We optimized a lon2 suppressor screen to expedite recovery of additional atg mutants. After screening mutagenized lon2-2 seedlings for restored IBA responsiveness, we evaluated stabilization and processing of peroxisomal proteins, levels of several ATG proteins, and levels of the selective autophagy receptor NBR1/At4g24690, which accumulates when autophagy is impaired. We recovered 21 alleles disrupting 6 ATG genes: ATG2/At3g19190, ATG3/At5g61500, ATG5/At5g17290, ATG7/At5g45900, ATG16/At5g50230, and ATG18a/At3g62770. Twenty alleles were novel, and 3 of the mutated genes lack T-DNA insertional alleles in publicly available repositories. We also demonstrate that an insertional atg11/At4g30790 allele incompletely suppresses lon2 defects. Finally, we show that NBR1 is not necessary for autophagy of lon2 peroxisomes and that NBR1 overexpression is not sufficient to trigger autophagy of seedling peroxisomes, indicating that Arabidopsis can use an NBR1-independent mechanism to target peroxisomes for autophagic degradation. Abbreviations: ATG: autophagy-related; ATI: ATG8-interacting protein; Col-0: Columbia-0; DSK2: dominant suppressor of KAR2; EMS: ethyl methanesulfonate; GFP: green fluorescent protein; IAA: indole-3-acetic acid; IBA: indole-3-butyric acid; ICL: isocitrate lyase; MLS: malate synthase; NBR1: Next to BRCA1 gene 1; PEX: peroxin; PMDH: peroxisomal malate dehydrogenase; PTS: peroxisomal targeting signal; thiolase: 3-ketoacyl-CoA thiolase; UBA: ubiquitin-associated; WT: wild type
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Affiliation(s)
- Pierce G Young
- a Department of Biosciences , Rice University , Houston , TX , USA
| | | | - Kevin Chappell
- a Department of Biosciences , Rice University , Houston , TX , USA.,b Department of Biology , University of Mary Hardin-Baylor , Belton , TX , USA
| | - Roxanna J Llinas
- a Department of Biosciences , Rice University , Houston , TX , USA
| | - Bonnie Bartel
- a Department of Biosciences , Rice University , Houston , TX , USA
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27
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Abstract
As a major intracellular degradation pathway, autophagy contributes to nutrient recycling and is indispensable during plant senescence. Here we describe methods used for investigating the autophagic process during leaf senescence. These include transcript analysis of core machinery autophagy genes, immunoblotting of ATG8, and microscopic observation of autophagosome formation.
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28
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Wojciechowska N, Marzec-Schmidt K, Kalemba EM, Zarzyńska-Nowak A, Jagodziński AM, Bagniewska-Zadworna A. Autophagy counteracts instantaneous cell death during seasonal senescence of the fine roots and leaves in Populus trichocarpa. BMC PLANT BIOLOGY 2018; 18:260. [PMID: 30373512 PMCID: PMC6206944 DOI: 10.1186/s12870-018-1439-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 09/24/2018] [Indexed: 05/22/2023]
Abstract
BACKGROUND Senescence, despite its destructive character, is a process that is precisely-regulated. The control of senescence is required to achieve remobilization of resources, a principle aspect of senescence. Remobilization allows plants to recapture valuable resources that would otherwise be lost to the environment with the senescing organ. Autophagy is one of the critical processes that is switched on during senescence. This evolutionarily conserved process plays dual, antagonistic roles. On the one hand, it counteracts instantaneous cell death and allows the process of remobilization to be set in motion, while on the other hand, it participates in the degradation of cellular components. Autophagy has been demonstrated to occur in many plant species during the senescence of leaves and flower petals. Little is known, however, about the senescence process in other ephemeral organs, such as fine roots, whose lifespan is also relatively short. We hypothesized that, like the case of seasonal leaf senescence, autophagy also plays a role in the senescence of fine roots, and that both processes are synchronized in their timing. RESULTS We evaluated which morphological and cytological symptoms are universal or unique in the senescence of fine roots and leaves. The results of our study confirmed that autophagy plays a key role in the senescence of fine roots, and is associated also with the process of cellular components degradation. In both organs, structures related to autophagy were observed, such as autophagic bodies and autophagosomes. The role of autophagy in the senescence of these plant organs was further confirmed by an analysis of ATG gene expression and protein detection. CONCLUSIONS The present study is the first one to examine molecular mechanisms associated with the senescence of fine roots, and provide evidence that can be used to determine whether senescence of fine roots can be treated as another example of developmentally programmed cell death (dPCD). Our results indicate that there is a strong similarity between the senescence of fine roots and other ephemeral organs, suggesting that this process occurs by the same autophagy-related mechanisms in all plant ephemeral organs.
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Affiliation(s)
- Natalia Wojciechowska
- Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Katarzyna Marzec-Schmidt
- Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Ewa M Kalemba
- Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland
| | - Aleksandra Zarzyńska-Nowak
- Department of Virusology and Bacteriology, Institute of Plant Protection, Węgorka 20, 60-318 Poznań, Poland
| | - Andrzej M Jagodziński
- Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland
| | - Agnieszka Bagniewska-Zadworna
- Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
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29
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Hirota T, Izumi M, Wada S, Makino A, Ishida H. Vacuolar Protein Degradation via Autophagy Provides Substrates to Amino Acid Catabolic Pathways as an Adaptive Response to Sugar Starvation in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2018; 59:1363-1376. [PMID: 29390157 DOI: 10.1093/pcp/pcy005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/04/2018] [Indexed: 05/28/2023]
Abstract
The vacuolar lytic degradation of proteins releases free amino acids that plants can use instead of sugars for respiratory energy production. Autophagy is a major cellular process leading to the transport of proteins into the vacuole for degradation. Here, we examine the contribution of autophagy to the amino acid metabolism response to sugar starvation in mature leaves of Arabidopsis thaliana. During sugar starvation arising from the exposure of wild-type (WT) plants to darkness, autophagic transport of chloroplast stroma, which contains most of the proteins in a leaf, into the vacuolar lumen was induced within 2 d. During this time, the level of soluble proteins, primarily Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase), decreased and the amount of free amino acid increased. In dark-treated autophagy-defective (atg) mutants, the decrease of soluble proteins was suppressed, which resulted in the compromised release of basic amino acids, branched-chain amino acids (BCAAs) and aromatic amino acids. The impairment of BCAA catabolic pathways in the knockout mutants of the electron transfer flavoprotein (ETF)/ETF:ubiquinone oxidoreductase (etfqo) complex and the electron donor protein isovaleryl-CoA dehydrogenase (ivdh) caused a reduced tolerance to dark treatment similar to that in the atg mutants. The enhanced accumulation of BCAAs in the ivdh and etfqo mutants during the dark treatment was reduced by additional autophagy deficiency. These results indicate that vacuolar protein degradation via autophagy serves as an adaptive response to disrupted photosynthesis by providing substrates to amino acid catabolic pathways, including BCAA catabolism mediated by IVDH and ETFQO.
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Affiliation(s)
- Takaaki Hirota
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, Aramaki Aza Aoba, Sendai, Japan
| | - Masanori Izumi
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aramaki Aza Aoba, Sendai, Japan
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Katahira, Sendai, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Shinya Wada
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, Aramaki Aza Aoba, Sendai, Japan
| | - Amane Makino
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, Aramaki Aza Aoba, Sendai, Japan
| | - Hiroyuki Ishida
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, Aramaki Aza Aoba, Sendai, Japan
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30
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Avin-Wittenberg T, Baluška F, Bozhkov PV, Elander PH, Fernie AR, Galili G, Hassan A, Hofius D, Isono E, Le Bars R, Masclaux-Daubresse C, Minina EA, Peled-Zehavi H, Coll NS, Sandalio LM, Satiat-Jeunemaitre B, Sirko A, Testillano PS, Batoko H. Autophagy-related approaches for improving nutrient use efficiency and crop yield protection. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1335-1353. [PMID: 29474677 DOI: 10.1093/jxb/ery069] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/16/2018] [Indexed: 05/18/2023]
Abstract
Autophagy is a eukaryotic catabolic pathway essential for growth and development. In plants, it is activated in response to environmental cues or developmental stimuli. However, in contrast to other eukaryotic systems, we know relatively little regarding the molecular players involved in autophagy and the regulation of this complex pathway. In the framework of the COST (European Cooperation in Science and Technology) action TRANSAUTOPHAGY (2016-2020), we decided to review our current knowledge of autophagy responses in higher plants, with emphasis on knowledge gaps. We also assess here the potential of translating the acquired knowledge to improve crop plant growth and development in a context of growing social and environmental challenges for agriculture in the near future.
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Affiliation(s)
- Tamar Avin-Wittenberg
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Frantisek Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Pernilla H Elander
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - Gad Galili
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot Israel
| | - Ammar Hassan
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Daniel Hofius
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, Uppsala, Sweden
| | - Erika Isono
- Department of Biology, University of Konstanz, Universitätsstrasse, Konstanz, Germany
| | - Romain Le Bars
- Cell Biology Pôle Imagerie-Gif, Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Céline Masclaux-Daubresse
- INRA-AgroParisTech, Institut Jean-Pierre Bourgin, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, Versailles, France
| | - Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Hadas Peled-Zehavi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot Israel
| | - Núria S Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra-Cerdanyola del Valles, Catalonia, Spain
| | - Luisa M Sandalio
- Departmento de Bioquímica, Biología Celular y Molecular de Plantas Experimental del Zaidín, CSIC, Granada, Spain
| | - Béatrice Satiat-Jeunemaitre
- Cell Biology Pôle Imagerie-Gif, Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Agnieszka Sirko
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, ul. Pawinskiego, Warsaw, Poland
| | - Pilar S Testillano
- Pollen Biotechnology of Crop Plants group, Centro de Investigaciones Biológicas, Biological Research Centre (CIB), CSIC, Ramiro de Maeztu, Madrid, Spain
| | - Henri Batoko
- Université Catholique de Louvain, Institute of Life Sciences, Croix du Sud, Louvain-la-Neuve, Belgium
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31
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Kalinowska K, Isono E. All roads lead to the vacuole-autophagic transport as part of the endomembrane trafficking network in plants. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1313-1324. [PMID: 29165603 DOI: 10.1093/jxb/erx395] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/14/2017] [Indexed: 05/10/2023]
Abstract
Plants regulate their development and response to the changing environment by sensing and interpreting environmental signals. Intracellular trafficking pathways including endocytic-, vacuolar-, and autophagic trafficking are important for the various aspects of responses in plants. Studies in the last decade have shown that the autophagic transport pathway uses common key components of endomembrane trafficking as well as specific regulators. A number of factors previously described for their function in endosomal trafficking have been discovered to be involved in the regulation of autophagy in plants. These include conserved endocytic machineries, such as the endosomal sorting complex required for transport (ESCRT), subunits of the HOPS and exocyst complexes, SNAREs, and RAB GTPases as well as plant-specific proteins. Defects in these factors have been shown to cause impairment of autophagosome formation, transport, fusion, and degradation, suggesting crosstalk between autophagy and other intracellular trafficking processes. In this review, we focus mainly on possible functions of endosomal trafficking components in autophagy.
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32
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Abstract
Most assimilated nutrients in the leaves of land plants are stored in chloroplasts as photosynthetic proteins, where they mediate CO2 assimilation during growth. During senescence or under suboptimal conditions, chloroplast proteins are degraded, and the amino acids released during this process are used to produce young tissues, seeds, or respiratory energy. Protein degradation machineries contribute to the quality control of chloroplasts by removing damaged proteins caused by excess energy from sunlight. Whereas previous studies revealed that chloroplasts contain several types of intraplastidic proteases that likely derived from an endosymbiosed prokaryotic ancestor of chloroplasts, recent reports have demonstrated that multiple extraplastidic pathways also contribute to chloroplast protein turnover in response to specific cues. One such pathway is autophagy, an evolutionarily conserved process that leads to the vacuolar or lysosomal degradation of cytoplasmic components in eukaryotic cells. Here, we describe and contrast the extraplastidic pathways that degrade chloroplasts. This review shows that diverse pathways participate in chloroplast turnover during sugar starvation, senescence, and oxidative stress. Elucidating the mechanisms that regulate these pathways will help decipher the relationship among the diverse pathways mediating chloroplast protein turnover.
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Affiliation(s)
- Masanori Izumi
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan.
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Kawaguchi 332-0012, Japan.
| | - Sakuya Nakamura
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
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33
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Abstract
As a representative form of plant senescence, leaf senescence has received the most attention during the last two decades. In this chapter we summarize the initiation of leaf senescence by various internal and external signals, the progression of senescence including switches in gene expression, as well as changes at the biochemical and cellular levels during leaf senescence. Impacts of leaf senescence in agriculture and genetic approaches that have been used in manipulating leaf senescence of crop plants are discussed.
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Affiliation(s)
- Akhtar Ali
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong, China.,Nuclear Institute for Food and Agriculture, Peshawar, Pakistan
| | - Xiaoming Gao
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong, China
| | - Yongfeng Guo
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong, China.
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34
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Izumi M, Nakamura S. Partial or entire: Distinct responses of two types of chloroplast autophagy. PLANT SIGNALING & BEHAVIOR 2017; 12:e1393137. [PMID: 29040052 PMCID: PMC5703251 DOI: 10.1080/15592324.2017.1393137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 10/12/2017] [Indexed: 05/24/2023]
Abstract
Autophagy carries out intracellular degradation of cytoplasmic components, which is important for the removal of dysfunctional organelles and for efficient nutrient recycling in eukaryotic cells. Most proteins in plant green tissues are found in chloroplasts, mainly as photosynthetic proteins that constantly accumulate damage caused by sunlight. Our recent study investigated the involvement of autophagy in the turnover of damaged chloroplasts and found that entire photodamaged chloroplasts are transported into the vacuole for degradation via an autophagy process termed chlorophagy. Our previous studies also established that autophagy can also degrade chloroplast components piecemeal: chloroplast stroma is transported for degradation via autophagy vesicles termed Rubisco-containing bodies (RCB). During sugar starvation-induced senescence in darkened leaves, the RCB pathway is preferentially active. By contrast, we observed active chlorophagy without prior induction of RCB production in photodamaged leaves. These distinct responses between the RCB pathway and chlorophagy support the notion that the induction of the partial-type and entire-organelle-type chloroplast autophagy are differentially regulated by individual upstream molecules. This finding further suggests that the two types of autophagy are coordinated to achieve the controlled chloroplast turnover in response to specific conditions.
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Affiliation(s)
- Masanori Izumi
- Creative Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Sakuya Nakamura
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
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35
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Bao Y, Mugume Y, Bassham DC. Biochemical Methods to Monitor Autophagic Responses in Plants. Methods Enzymol 2016; 588:497-513. [PMID: 28237117 DOI: 10.1016/bs.mie.2016.09.090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The study of autophagy in plants is rapidly increasing, due to its pivotal and fundamental roles in responding to stressful stimuli, recycling nutrients during senescence, and maintaining growth under normal conditions. Assays for detecting autophagy in plants have generally been based on microscopic observations, providing qualitative information on autophagy activity. Here, we discuss biochemical assays for detecting autophagy, which have the potential for providing more quantitative information, with a focus on immunoblotting with antibodies against ATG8, NBR1, or epitope tags fused to ATG proteins.
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Affiliation(s)
- Y Bao
- Iowa State University, Ames, IA, United States
| | - Y Mugume
- Iowa State University, Ames, IA, United States
| | - D C Bassham
- Iowa State University, Ames, IA, United States.
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36
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New Insight into the Mechanism and Function of Autophagy in Plant Cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 320:1-40. [PMID: 26614870 DOI: 10.1016/bs.ircmb.2015.07.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Autophagy is a degradation pathway that is conserved throughout eukaryotic organisms and plays important roles in the tolerance of abiotic and biotic stresses. It functions as a housekeeping process to remove unwanted cell components under normal conditions, and is induced during stress and senescence to break down damaged cellular contents and to recycle materials. The target components are engulfed into specialized transport structures termed autophagosomes and are subsequently delivered to the vacuole for degradation. Here, we review milestones in the study of autophagy in plants, discuss recent advances in our understanding of the mechanism and physiological roles of plant autophagy, and highlight potential future directions of research.
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37
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Zhou XM, Zhao P, Wang W, Zou J, Cheng TH, Peng XB, Sun MX. A comprehensive, genome-wide analysis of autophagy-related genes identified in tobacco suggests a central role of autophagy in plant response to various environmental cues. DNA Res 2015; 22:245-57. [PMID: 26205094 PMCID: PMC4535619 DOI: 10.1093/dnares/dsv012] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/21/2015] [Indexed: 11/14/2022] Open
Abstract
Autophagy is an evolutionarily conserved mechanism in both animals and plants, which has been shown to be involved in various essential developmental processes in plants. Nicotiana tabacum is considered to be an ideal model plant and has been widely used for the study of the roles of autophagy in the processes of plant development and in the response to various stresses. However, only a few autophagy-related genes (ATGs) have been identified in tobacco up to now. Here, we identified 30 ATGs belonging to 16 different groups in tobacco through a genome-wide survey. Comprehensive expression profile analysis reveals an abroad expression pattern of these ATGs, which could be detected in all tissues tested under normal growth conditions. Our series tests further reveal that majority of ATGs are sensitive and responsive to different stresses including nutrient starvation, plant hormones, heavy metal and other abiotic stresses, suggesting a central role of autophagy, likely as an effector, in plant response to various environmental cues. This work offers a detailed survey of all ATGs in tobacco and also suggests manifold functions of autophagy in both normal plant growth and plant response to environmental stresses.
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Affiliation(s)
- Xue-mei Zhou
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Peng Zhao
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Wei Wang
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Jie Zou
- Molecular Genetics Key Laboratory of China Tobacco, Guizhou Academy of Tobacco Science, Guiyang 550081, China
| | - Tian-he Cheng
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Xiong-bo Peng
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Meng-xiang Sun
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
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38
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van Wijk KJ. Protein maturation and proteolysis in plant plastids, mitochondria, and peroxisomes. ANNUAL REVIEW OF PLANT BIOLOGY 2015; 66:75-111. [PMID: 25580835 DOI: 10.1146/annurev-arplant-043014-115547] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plastids, mitochondria, and peroxisomes are key organelles with dynamic proteomes in photosynthetic eukaryotes. Their biogenesis and activity must be coordinated and require intraorganellar protein maturation, degradation, and recycling. The three organelles together are predicted to contain ∼200 presequence peptidases, proteases, aminopeptidases, and specific protease chaperones/adaptors, but the substrates and substrate selection mechanisms are poorly understood. Similarly, lifetime determinants of organellar proteins, such as N-end degrons and tagging systems, have not been identified, but the substrate recognition mechanisms likely share similarities between organelles. Novel degradomics tools for systematic analysis of protein lifetime and proteolysis could define such protease-substrate relationships, degrons, and protein lifetime. Intraorganellar proteolysis is complemented by autophagy of whole organelles or selected organellar content, as well as by cytosolic protein ubiquitination and degradation by the proteasome. This review summarizes (putative) plant organellar protease functions and substrate-protease relationships. Examples illustrate key proteolytic events.
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Affiliation(s)
- Klaas J van Wijk
- Department of Plant Biology, Cornell University, Ithaca, New York 14853;
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39
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Izumi M, Hidema J, Ishida H. From Arabidopsis to cereal crops: Conservation of chloroplast protein degradation by autophagy indicates its fundamental role in plant productivity. PLANT SIGNALING & BEHAVIOR 2015; 10:e1101199. [PMID: 26440746 PMCID: PMC4883919 DOI: 10.1080/15592324.2015.1101199] [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] [Indexed: 05/08/2023]
Abstract
Autophagy is an evolutionarily conserved process leading to the degradation of intracellular components in eukaryotes, which is important for nutrient recycling especially in response to starvation conditions. Nutrient recycling is an essential process that underpins productivity in crop plants, such that remobilized nitrogen derived from older organs supports the formation of new organs or grain-filling within a plant. We extended our understanding of autophagy in a model plant, Arabidopsis thaliana, to an important cereal, rice (Oryza sativa). Through analysis of transgenic rice plants stably expressing fluorescent marker proteins for autophagy or chloroplast stroma, we revealed that chloroplast proteins are partially degraded in the vacuole via Rubisco-containing bodies (RCBs), a type of autophagosomes containing stroma. We further reported evidence that the RCB pathway functions during natural leaf senescence to facilitate subsequent nitrogen remobilization into newly expanding leaves. Thus, our recent studies establish the importance of autophagy in biomass production of cereals.
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Affiliation(s)
- Masanori Izumi
- Frontier Research Institute for Interdisciplinary Sciences; Tohoku University; Sendai, Japan
- Department of Environmental Life Sciences; Graduate School of Life Sciences; Tohoku University; Sendai, Japan
| | - Jun Hidema
- Department of Environmental Life Sciences; Graduate School of Life Sciences; Tohoku University; Sendai, Japan
| | - Hiroyuki Ishida
- Department of Applied Plant Science; Graduate School of Agricultural Sciences; Tohoku University; Sendai, Japan
- Correspondence to: Hiroyuki Ishida;
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40
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Reddy MM, Ulaganathan K. Nitrogen Nutrition, Its Regulation and Biotechnological Approaches to Improve Crop Productivity. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/ajps.2015.618275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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41
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Broderick SR, Wijeratne S, Wijeratn AJ, Chapin LJ, Meulia T, Jones ML. RNA-sequencing reveals early, dynamic transcriptome changes in the corollas of pollinated petunias. BMC PLANT BIOLOGY 2014; 14:307. [PMID: 25403317 PMCID: PMC4245787 DOI: 10.1186/s12870-014-0307-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/27/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND Pollination reduces flower longevity in many angiosperms by accelerating corolla senescence. This response requires hormone signaling between the floral organs and results in the degradation of macromolecules and organelles within the petals to allow for nutrient remobilization to developing seeds. To investigate early pollination-induced changes in petal gene expression, we utilized high-throughput sequencing to identify transcripts that were differentially expressed between corollas of pollinated Petunia × hybrida flowers and their unpollinated controls at 12, 18, and 24 hours after opening. RESULTS In total, close to 0.5 billion Illumina 101 bp reads were generated, de novo assembled, and annotated, resulting in an EST library of approximately 33 K genes. Over 4,700 unique, differentially expressed genes were identified using comparisons between the pollinated and unpollinated libraries followed by pairwise comparisons of pollinated libraries to unpollinated libraries from the same time point (i.e. 12-P/U, 18-P/U, and 24-P/U) in the Bioconductor R package DESeq2. Over 500 gene ontology terms were enriched. The response to auxin stimulus and response to 1-aminocyclopropane-1-carboxylic acid terms were enriched by 12 hours after pollination (hap). Using weighted gene correlation network analysis (WGCNA), three pollination-specific modules were identified. Module I had increased expression across pollinated corollas at 12, 18, and 24 h, and modules II and III had a peak of expression in pollinated corollas at 18 h. A total of 15 enriched KEGG pathways were identified. Many of the genes from these pathways were involved in metabolic processes or signaling. More than 300 differentially expressed transcription factors were identified. CONCLUSIONS Gene expression changes in corollas were detected within 12 hap, well before fertilization and corolla wilting or ethylene evolution. Significant changes in gene expression occurred at 18 hap, including the up-regulation of autophagy and down-regulation of ribosomal genes and genes involved in carbon fixation. This transcriptomic database will greatly expand the genetic resources available in petunia. Additionally, it will guide future research aimed at identifying the best targets for increasing flower longevity by delaying corolla senescence.
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Affiliation(s)
- Shaun R Broderick
- />Department of Horticulture and Crop Science, The Ohio Agricultural Research and Development Center, The Ohio State University, 1680 Madison Ave, Wooster, OH 44691 USA
| | - Saranga Wijeratne
- />Molecular and Cellular Imaging Center, The Ohio Agricultural Research and Development Center, The Ohio State University, 1680 Madison Ave, Wooster, OH 44691 USA
| | - Asela J Wijeratn
- />Molecular and Cellular Imaging Center, The Ohio Agricultural Research and Development Center, The Ohio State University, 1680 Madison Ave, Wooster, OH 44691 USA
| | - Laura J Chapin
- />Department of Horticulture and Crop Science, The Ohio Agricultural Research and Development Center, The Ohio State University, 1680 Madison Ave, Wooster, OH 44691 USA
| | - Tea Meulia
- />Molecular and Cellular Imaging Center, The Ohio Agricultural Research and Development Center, The Ohio State University, 1680 Madison Ave, Wooster, OH 44691 USA
| | - Michelle L Jones
- />Department of Horticulture and Crop Science, The Ohio Agricultural Research and Development Center, The Ohio State University, 1680 Madison Ave, Wooster, OH 44691 USA
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Senescence-Associated Vacuoles, a Specific Lytic Compartment for Degradation of Chloroplast Proteins? PLANTS 2014; 3:498-512. [PMID: 27135516 PMCID: PMC4844279 DOI: 10.3390/plants3040498] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 09/14/2014] [Accepted: 09/15/2014] [Indexed: 11/21/2022]
Abstract
Degradation of chloroplasts and chloroplast components is a distinctive feature of leaf senescence. In spite of its importance in the nutrient economy of plants, knowledge about the mechanism(s) involved in the breakdown of chloroplast proteins is incomplete. A novel class of vacuoles, “senescence-associated vacuoles” (SAVs), characterized by intense proteolytic activity appear during senescence in chloroplast-containing cells of leaves. Since SAVs contain some chloroplast proteins, they are candidate organelles to participate in chloroplast breakdown. In this review we discuss the characteristics of SAVs, and their possible involvement in the degradation of Rubisco, the most abundant chloroplast protein. Finally, SAVs are compared with other extra-plastidial protein degradation pathways operating in senescing leaves.
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Michaeli S, Honig A, Levanony H, Peled-Zehavi H, Galili G. Arabidopsis ATG8-INTERACTING PROTEIN1 is involved in autophagy-dependent vesicular trafficking of plastid proteins to the vacuole. THE PLANT CELL 2014; 26:4084-101. [PMID: 25281689 PMCID: PMC4247578 DOI: 10.1105/tpc.114.129999] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 08/28/2014] [Accepted: 09/18/2014] [Indexed: 05/18/2023]
Abstract
Selective autophagy has been extensively studied in various organisms, but knowledge regarding its functions in plants, particularly in organelle turnover, is limited. We have recently discovered ATG8-INTERACTING PROTEIN1 (ATI1) from Arabidopsis thaliana and showed that following carbon starvation it is localized on endoplasmic reticulum (ER)-associated bodies that are subsequently transported to the vacuole. Here, we show that following carbon starvation ATI1 is also located on bodies associating with plastids, which are distinct from the ER ATI bodies and are detected mainly in senescing cells that exhibit plastid degradation. Additionally, these plastid-localized bodies contain a stroma protein marker as cargo and were observed budding and detaching from plastids. ATI1 interacts with plastid-localized proteins and was further shown to be required for the turnover of one of them, as a representative. ATI1 on the plastid bodies also interacts with ATG8f, which apparently leads to the targeting of the plastid bodies to the vacuole by a process that requires functional autophagy. Finally, we show that ATI1 is involved in Arabidopsis salt stress tolerance. Taken together, our results implicate ATI1 in autophagic plastid-to-vacuole trafficking through its ability to interact with both plastid proteins and ATG8 of the core autophagy machinery.
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Affiliation(s)
- Simon Michaeli
- Department of Plant Science, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Arik Honig
- Department of Plant Science, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hanna Levanony
- Department of Plant Science, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hadas Peled-Zehavi
- Department of Plant Science, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Gad Galili
- Department of Plant Science, The Weizmann Institute of Science, Rehovot 76100, Israel
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Abstract
Stay-green (sometimes staygreen) refers to the heritable delayed foliar senescence character in model and crop plant species. In a cosmetic stay-green, a lesion interferes with an early step in chlorophyll catabolism. The possible contribution of synthesis to chlorophyll turnover in cosmetic stay-greens is considered. In functional stay-greens, the transition from the carbon capture period to the nitrogen mobilization (senescence) phase of canopy development is delayed, and/or the senescence syndrome proceeds slowly. Yield and composition in high-carbon (C) crops such as cereals, and in high-nitrogen (N) species such as legumes, reflect the source-sink relationship with canopy C capture and N remobilization. Quantitative trait loci studies show that functional stay-green is a valuable trait for improving crop stress tolerance, and is associated with the domestication syndrome in cereals. Stay-green variants reveal how autumnal senescence and dormancy are coordinated in trees. The stay-green phenotype can be the result of alterations in hormone metabolism and signalling, particularly affecting networks involving cytokinins and ethylene. Members of the WRKY and NAC families, and an ever-expanding cast of additional senescence-associated transcription factors, are identifiable by mutations that result in stay-green. Empirical selection for functional stay-green has contributed to increasing crop yields, particularly where it is part of a strategy that also targets other traits such as sink capacity and environmental sensitivity and is associated with appropriate crop management methodology. The onset and progress of senescence are phenological metrics that show climate change sensitivity, indicating that understanding stay-green can contribute to the design of appropriate crop types for future environments.
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Affiliation(s)
- Howard Thomas
- IBERS, Edward Llwyd Building, Aberystwyth University, Ceredigion SY23 3FG, UK
| | - Helen Ougham
- IBERS, Edward Llwyd Building, Aberystwyth University, Ceredigion SY23 3FG, UK
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45
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Avice JC, Etienne P. Leaf senescence and nitrogen remobilization efficiency in oilseed rape (Brassica napus L.). JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3813-24. [PMID: 24790115 DOI: 10.1093/jxb/eru177] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Despite its worldwide economic importance for food (oil, meal) and non-food (green energy and chemistry) uses, oilseed rape has a low nitrogen (N) use efficiency (NUE), mainly due to the low N remobilization efficiency (NRE) observed during the vegetative phase when sequential leaf senescence occurs. Assuming that improvement of NRE is the main lever for NUE optimization, unravelling the cellular mechanisms responsible for the recycling of proteins (the main N source in leaf) during sequential senescence is a prerequisite for identifying the physiological and molecular determinants that are associated with high NRE. The development of a relevant molecular indicator (SAG12/Cab) of leaf senescence progression in combination with a (15)N-labelling method were used to decipher the N remobilization associated with sequential senescence and to determine modulation of this process by abiotic factors especially N deficiency. Interestingly, in young leaves, N starvation delayed senescence and induced BnD22, a water-soluble chlorophyll-binding protein that acts against oxidative alterations of chlorophylls and exhibits a protease inhibitor activity. Through its dual function, BnD22 may help to sustain sink growth of stressed plants and contribute to a better utilization of N recycled from senescent leaves, a physiological trait that could improve NUE. Proteomics approaches have revealed that proteolysis involves chloroplastic FtsH protease in the early stages of senescence, aspartic protease during the course of leaf senescence, and the proteasome β1 subunit, mitochondria processing protease and SAG12 (cysteine protease) during the later senescence phases. Overall, the results constitute interesting pathways for screening genotypes with high NRE and NUE.
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Affiliation(s)
- Jean-Christophe Avice
- Normandie University, F-14032 Caen, France UCBN, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & nutritions N.C.S., F-14032 Caen, France INRA, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & nutritions N.C.S., F-14032 Caen, France
| | - Philippe Etienne
- Normandie University, F-14032 Caen, France UCBN, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & nutritions N.C.S., F-14032 Caen, France INRA, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & nutritions N.C.S., F-14032 Caen, France
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46
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Distelfeld A, Avni R, Fischer AM. Senescence, nutrient remobilization, and yield in wheat and barley. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3783-98. [PMID: 24470467 DOI: 10.1093/jxb/ert477] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Cereals including wheat and barley are of primary importance to ensure food security for the 21st century. A combination of lab- and field-based approaches has led to a considerably improved understanding of the importance of organ and particularly of whole-plant (monocarpic) senescence for wheat and barley yield and quality. A delicate balance between senescence timing, grain nutrient content, nutrient-use efficiency, and yield needs to be considered to (further) improve cereal varieties for a given environment and end use. The recent characterization of the Gpc-1 (NAM-1) genes in wheat and barley demonstrates the interdependence of these traits. Lines or varieties with functional Gpc-1 genes demonstrate earlier senescence and enhanced grain protein and micronutrient content but, depending on the environment, somewhat reduced yields. A major effort is needed to dissect regulatory networks centred on additional wheat and barley transcription factors and signalling pathways influencing the senescence process. Similarly, while important molecular details of nutrient (particularly nitrogen) remobilization from senescing organs to developing grains have been identified, important knowledge gaps remain. The genes coding for the major proteases involved in senescence-associated plastidial protein degradation are largely unknown. Membrane transport proteins involved in the different transport steps occurring between senescing organ (such as leaf mesophyll) cells and protein bodies in the endosperm of developing grains remain to be identified or further characterized. Existing data suggest that an improved understanding of all these steps will reveal additional, important targets for continued cereal improvement.
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Affiliation(s)
- Assaf Distelfeld
- Faculty of Life Sciences, Department of Molecular Biology and Ecology of Plants, Tel Aviv University, 69978, Israel
| | - Raz Avni
- Faculty of Life Sciences, Department of Molecular Biology and Ecology of Plants, Tel Aviv University, 69978, Israel
| | - Andreas M Fischer
- Department of Plant Sciences and Plant Pathology, 119 Plant BioScience Building, Montana State University, Bozeman, MT 59717-3150, USA
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Chen Y, Chen X, Wang H, Bao Y, Zhang W. Examination of the leaf proteome during flooding stress and the induction of programmed cell death in maize. Proteome Sci 2014; 12:33. [PMID: 25028572 PMCID: PMC4099015 DOI: 10.1186/1477-5956-12-33] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/30/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Maize is a major economic crop worldwide, with substantial crop loss attributed to flooding. During a stress response, programmed cell death (PCD) can be an effective way for plants better adapt. To identify flooding stress related PCD proteins in maize leaves, proteomic analysis was performed using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and mass spectrometry. RESULTS Comparative proteomics was combined with physiological and biochemical analysis of maize leaves under flooding stress. Fv/Fm, qP, qN and relative water content (RWC) were found to be altered in response to flooding stress, with an increase in H2O2 content noted in vivo. Furthermore, DNA ladder detection indicated that PCD had occurred under flooding treatment. The maize leaf proteome was analyzed via 2D-DIGE gel, with a total of 32 differentially expressed spots isolated, 31 spots were successfully identified via MALDI-TOF/TOF MS which represent 28 proteins. The identified proteins were related to energy metabolism and photosynthesis, PCD, phytohormones and polyamines. To better characterize the role of translationally controlled tumor protein (TCTP) in PCD during a stress response, mRNA expression was examined in different plants by stress-induced PCD. These included heat stress induced rice protoplasts, Tobacco Mosaic Virus infected tobacco leaves and dark induced rice and Arabidopsis thaliana leaves, all of which showed active PCD, and TCTP expression was increased in different degrees. Moreover, S-adenosylmethionine synthase 2 (SAMS2) and S-adenosylmethionine decarboxylase (SAMDC) mRNA expression were also increased, but ACC synthase (ACS) and ACC oxidase (ACO) mRNA expression were not found in maize leaves following flooding. Lastly, ethylene and polyamine concentrations were increased in response to flooding treatment in maize leaves. CONCLUSIONS Following flooding stress, the photosynthetic systems were damaged, resulting in a disruption in energy metabolism, with the noted photosynthetic decline also possibly attributed to ROS production. The observed PCD could be regulated by TCTP with a possible role for H2O2 in TCTP induction under flooding stress. Additionally, increased SAMS2 expression was closely associated with an increased polyamine synthesis during flooding treatment.
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Affiliation(s)
- Yu Chen
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR, China
| | - Xi Chen
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR, China
| | - Hongjuan Wang
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR, China
| | - Yiqun Bao
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR, China
| | - Wei Zhang
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR, China
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Masclaux-Daubresse C, Clément G, Anne P, Routaboul JM, Guiboileau A, Soulay F, Shirasu K, Yoshimoto K. Stitching together the Multiple Dimensions of Autophagy Using Metabolomics and Transcriptomics Reveals Impacts on Metabolism, Development, and Plant Responses to the Environment in Arabidopsis. THE PLANT CELL 2014; 26:1857-1877. [PMID: 24808053 PMCID: PMC4079355 DOI: 10.1105/tpc.114.124677] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 03/21/2014] [Accepted: 04/13/2014] [Indexed: 05/18/2023]
Abstract
Autophagy is a fundamental process in the plant life story, playing a key role in immunity, senescence, nutrient recycling, and adaptation to the environment. Transcriptomics and metabolomics of the rosette leaves of Arabidopsis thaliana autophagy mutants (atg) show that autophagy is essential for cell homeostasis and stress responses and that several metabolic pathways are affected. Depletion of hexoses, quercetins, and anthocyanins parallel the overaccumulation of several amino acids and related compounds, such as glutamate, methionine, glutathione, pipecolate, and 2-aminoadipate. Transcriptomic data show that the pathways for glutathione, methionine, raffinose, galacturonate, and anthocyanin are perturbed. Anthocyanin depletion in atg mutants, which was previously reported as a possible defect in flavonoid trafficking to the vacuole, appears due to the downregulation of the master genes encoding the enzymes and regulatory proteins involved in flavonoid biosynthesis. Overexpression of the PRODUCTION OF ANTHOCYANIN PIGMENT1 transcription factor restores anthocyanin accumulation in vacuoles of atg mutants. Transcriptome analyses reveal connections between autophagy and (1) salicylic acid biosynthesis and response, (2) cytokinin perception, (3) oxidative stress and plant defense, and possible interactions between autophagy and the COP9 signalosome machinery. The metabolic and transcriptomic signatures identified for the autophagy mutants are discussed and show consistencies with the observed phenotypes.
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Affiliation(s)
- Céline Masclaux-Daubresse
- Unité Mixte de Recherche 1318, INRA, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France AgroParisTech, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
| | - Gilles Clément
- Unité Mixte de Recherche 1318, INRA, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France AgroParisTech, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
| | - Pauline Anne
- Unité Mixte de Recherche 1318, INRA, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France AgroParisTech, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
| | - Jean-Marc Routaboul
- Unité Mixte de Recherche 1318, INRA, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France AgroParisTech, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
| | - Anne Guiboileau
- Unité Mixte de Recherche 1318, INRA, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France AgroParisTech, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
| | - Fabienne Soulay
- Unité Mixte de Recherche 1318, INRA, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France AgroParisTech, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
| | - Ken Shirasu
- RIKEN, Plant Science Center, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Kohki Yoshimoto
- Unité Mixte de Recherche 1318, INRA, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France AgroParisTech, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France RIKEN, Plant Science Center, Tsurumi-ku, Yokohama 230-0045, Japan
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49
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Griffiths CA, Gaff DF, Neale AD. Drying without senescence in resurrection plants. FRONTIERS IN PLANT SCIENCE 2014; 5:36. [PMID: 24575108 PMCID: PMC3922084 DOI: 10.3389/fpls.2014.00036] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 01/27/2014] [Indexed: 05/16/2023]
Abstract
Research into extreme drought tolerance in resurrection plants using species such as Craterostigma plantagineum, C. wilmsii, Xerophyta humilis, Tortula ruralis, and Sporobolus stapfianus has provided some insight into the desiccation tolerance mechanisms utilized by these plants to allow them to persist under extremely adverse environmental conditions. Some of the mechanisms used to ensure cellular preservation during severe dehydration appear to be peculiar to resurrection plants. Apart from the ability to preserve vital cellular components during drying and rehydration, such mechanisms include the ability to down-regulate growth-related metabolism rapidly in response to changes in water availability, and the ability to inhibit dehydration-induced senescence programs enabling reconstitution of photosynthetic capacity quickly following a rainfall event. Extensive research on the molecular mechanism of leaf senescence in non-resurrection plants has revealed a multi-layered regulatory network operates to control programed cell death pathways. However, very little is known about the molecular mechanisms that resurrection plants employ to avoid undergoing drought-related senescence during the desiccation process. To survive desiccation, dehydration in the perennial resurrection grass S. stapfianus must proceed slowly over a period of 7 days or more. Leaves detached from the plant before 60% relative water content (RWC) is attained are desiccation-sensitive indicating that desiccation tolerance is conferred in vegetative tissue of S. stapfianus when the leaf RWC has declined to 60%. Whilst some older leaves remaining attached to the plant during dehydration will senesce, suggesting dehydration-induced senescence may be influenced by leaf age or the rate of dehydration in individual leaves, the majority of leaves do not senesce. Rather these leaves dehydrate to air-dryness and revive fully following rehydration. Hence it seems likely that there are genes expressed in younger leaf tissues of resurrection plants that enable suppression of drought-related senescence pathways. As very few studies have directly addressed this phenomenon, this review aims to discuss current literature surrounding the activation and suppression of senescence pathways and how these pathways may differ in resurrection plants.
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Affiliation(s)
| | | | - Alan D. Neale
- School of Biological Sciences, Monash UniversityClayton, VIC, Australia
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50
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Li SP, Hu KD, Hu LY, Li YH, Jiang AM, Xiao F, Han Y, Liu YS, Zhang H. Hydrogen sulfide alleviates postharvest senescence of broccoli by modulating antioxidant defense and senescence-related gene expression. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:1119-29. [PMID: 24422501 DOI: 10.1021/jf4047122] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Accumulating evidence has shown that hydrogen sulfide (H₂S) acts as a signaling regulator in plants. Here we show that H₂S delays the postharvest senescence of broccoli in a dose-dependent manner. H₂S maintains higher levels of metabolites, such as carotenoids, anthocyanin, and ascorbate, and reduces the accumulation of malondialdehyde, H₂O₂, and the superoxide anion. Further investigations showed that H₂S sustained higher activities of guaiacol peroxidase, ascorbate peroxidase, catalase, and glutathione reductase and lower activities of lipoxygenase, polyphenol oxidase, phenylalanine ammonia lyase, and protease than those of water control. Moreover, the expression of the chlorophyll degradation related genes BoSGR, BoCLH2, BoPaO, BoRCCR, as well as cysteine protease BoCP1 and lipoxygenase gene BoLOX1, was down-regulated in postharvest broccoli treated with H₂S. The functions of H₂S on the senescence of other vegetables and fruits suggest its universal role acting as a senescence regulator.
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Affiliation(s)
- Shi-Ping Li
- School of Biotechnology and Food Engineering, Hefei University of Technology , Hefei 230009, China
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