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Erlichman OA, Weiss S, Abu Arkia M, Ankary-Khaner M, Soroka Y, Jasinska W, Rosental L, Brotman Y, Avin-Wittenberg T. Autophagy in maternal tissues contributes to Arabidopsis seed development. PLANT PHYSIOLOGY 2023; 193:611-626. [PMID: 37313772 DOI: 10.1093/plphys/kiad350] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 06/15/2023]
Abstract
Seeds are an essential food source, providing nutrients for germination and early seedling growth. Degradation events in the seed and the mother plant accompany seed development, including autophagy, which facilitates cellular component breakdown in the lytic organelle. Autophagy influences various aspects of plant physiology, specifically nutrient availability and remobilization, suggesting its involvement in source-sink interactions. During seed development, autophagy affects nutrient remobilization from mother plants and functions in the embryo. However, it is impossible to distinguish between the contribution of autophagy in the source (i.e. the mother plant) and the sink tissue (i.e. the embryo) when using autophagy knockout (atg mutant) plants. To address this, we employed an approach to differentiate between autophagy in source and sink tissues. We investigated how autophagy in the maternal tissue affects seed development by performing reciprocal crosses between wild type and atg mutant Arabidopsis (Arabidopsis thaliana) plants. Although F1 seedlings possessed a functional autophagy mechanism, etiolated F1 plants from maternal atg mutants displayed reduced growth. This was attributed to altered protein but not lipid accumulation in the seeds, suggesting autophagy differentially regulates carbon and nitrogen remobilization. Surprisingly, F1 seeds of maternal atg mutants exhibited faster germination, resulting from altered seed coat development. Our study emphasizes the importance of examining autophagy in a tissue-specific manner, revealing valuable insights into the interplay between different tissues during seed development. It also sheds light on the tissue-specific functions of autophagy, offering potential for research into the underlying mechanisms governing seed development and crop yield.
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Affiliation(s)
- Ori Avraham Erlichman
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Shahar Weiss
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Maria Abu Arkia
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Moria Ankary-Khaner
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Yoram Soroka
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Weronika Jasinska
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Leah Rosental
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Yariv Brotman
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Tamar Avin-Wittenberg
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
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2
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Wang Y, Ye H, Gao K, Li G, Xu Q, Deng X, Li J, Mei F, Zhou Z. The opening of mitochondrial permeability transition pore (mPTP) and the inhibition of electron transfer chain (ETC) induce mitophagy in wheat roots under waterlogging stress. PROTOPLASMA 2023; 260:1179-1191. [PMID: 36745240 DOI: 10.1007/s00709-022-01834-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/22/2022] [Indexed: 06/07/2023]
Abstract
Mitochondria are crucial for the regulation of intracellular energy metabolism, biosynthesis, and cell survival. And studies have demonstrated the role of mitochondria in oxidative stress-induced autophagy in plants. Previous studies found that waterlogging stress can induce the opening of mitochondrial permeability transition pore (mPTP) and the release of cytochrome c in endosperm cells, which proved that mPTP plays an important role in the programmed cell death of endosperm cells under waterlogging stress. This study investigated the effects of the opening of mPTP and the inhibition of ETC on mitophagy in wheat roots under waterlogging stress. The results showed that autophagy related genes in the mitochondria of wheat root cells could respond to waterlogging stress; waterlogging stress led to the degradation of the characteristic proteins cytochrome c and COXII in the mitochondria of root cells. With the prolongation of waterlogging time, the protein degradation degree and the occurrence of mitophagy gradually increased. Under waterlogging stress, exogenous mPTP opening inhibitor CsA inhibited mitophagy in root cells and alleviated mitophagy induced by flooding stress, while exogenous mPTP opening inducer CCCP induced mitophagy in root cells; exogenous mPTP opening inducer CCCP induced mitophagy in root cells. The electron transfer chain inhibitor antimycin A induces mitophagy in wheat root cells and exacerbates mitochondrial degradation. In conclusion, waterlogging stress led to the degradation of mitochondrial characteristic proteins and the occurrence of mitophagy in wheat root cells, and the opening of mPTP and the inhibition of ETC induced the occurrence of mitophagy.
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Affiliation(s)
- Yueli Wang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Hailong Ye
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Kaiyue Gao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Gege Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Qiutao Xu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Xiangyi Deng
- College of Food and Biological Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Jiwei Li
- College of Food and Biological Science and Technology, Wuhan Institute of Design and Sciences, Wuhan, 430070, Hubei, China
| | - Fangzhu Mei
- Division of Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Zhuqing Zhou
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
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3
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Nick P, Kölreuter JG. FfF: Foundations for Food (security) are cellular. PROTOPLASMA 2023:10.1007/s00709-023-01869-z. [PMID: 37264254 DOI: 10.1007/s00709-023-01869-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- Peter Nick
- Joseph Gottlieb Kölreuter Institute for Plant Sciences, Karlsruhe Institute of Technology, Karlsruhe, Germany.
| | - Joseph Gottlieb Kölreuter
- Joseph Gottlieb Kölreuter Institute for Plant Sciences, Karlsruhe Institute of Technology, Karlsruhe, Germany
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4
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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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Creighton MT, Nemie-Feyissa D, Zaman N, Johansen SS, Dysjaland H, Heidari B, Lillo C. Loss of LEUCINE CARBOXYL METHYLTRANSFERASE 1 interferes with metal homeostasis in Arabidopsis and enhances susceptibility to environmental stresses. JOURNAL OF PLANT PHYSIOLOGY 2022; 279:153843. [PMID: 36265226 DOI: 10.1016/j.jplph.2022.153843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 09/30/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
The biochemical function of LEUCINE CARBOXYL METHYLTRANSFERASE 1 (LCMT1) is to transfer a methyl group from the methyl donor S-adenosylmethionine (SAM) to the catalytic subunits of PROTEIN PHOSPHATASE 2A (PP2Ac), PP4 and PP6. This post-translational modification by LCMT1 is found throughout eukaryotes from yeast to animals and plants, indicating that its function is essential. However, Arabidopsis with knocked out LCMT1 still grows and develops almost normally, at least under optimal growth conditions. We therefore proposed that the presence of LCMT1 would be important under non-optimal growth conditions and favoured plant survival during evolution. To shed light on the physiological functions of plant LCMT1, phenotypes of the lcmt1 mutant and wild type Arabidopsis were compared under various conditions including exposure to heavy metals, variable chelator concentrations, and increased temperature. The lcmt1 mutant was found to be more susceptible to these environmental changes than wild type and resulted in poor growth of seedlings and rosette stage plants. Element analysis of rosette stage plants mainly showed a difference between the lcmt1 mutant and wild type regarding concentrations of sodium and boron, two-fold up or halved, respectively. In both lcmt1 and wild type, lack of EDTA in the growth medium resulted in enhanced concentration of copper, manganese, zinc and sulphur, and especially lcmt1 growth was hampered by these conditions. The altered phenotype in response to stress, the element and mRNA transcript analysis substantiate that LCMT1 has an important role in metal homeostasis and show that functional LCMT1 is necessary to prevent damages from heat, heavy metals or lack of chelator.
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Affiliation(s)
- Maria T Creighton
- IKBM, Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway
| | - Dugassa Nemie-Feyissa
- IKBM, Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway
| | - Nabeela Zaman
- IKBM, Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway
| | - Sverre S Johansen
- IKBM, Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway
| | - Hege Dysjaland
- IKBM, Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway
| | - Behzad Heidari
- IKBM, Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway
| | - Cathrine Lillo
- IKBM, Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway.
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6
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Popov VN, Syromyatnikov MY, Franceschi C, Moskalev AA, Krutovsky KV, Krutovsky KV. Genetic mechanisms of aging in plants: What can we learn from them? Ageing Res Rev 2022; 77:101601. [PMID: 35278719 DOI: 10.1016/j.arr.2022.101601] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 02/03/2022] [Accepted: 03/02/2022] [Indexed: 12/18/2022]
Abstract
Plants hold all records in longevity. Their aging is a complex process. In the presented review, we analyzed published data on various aspects of plant aging with focus on any inferences that could shed a light on aging in animals and help to fight it in human. Plant aging can be caused by many factors, such as telomere depletion, genomic instability, loss of proteostasis, changes in intercellular interaction, desynchronosis, autophagy misregulation, epigenetic changes and others. Plants have developed a number of mechanisms to increase lifespan. Among these mechanisms are gene duplication ("genetic backup"), the active work of telomerases, abundance of meristematic cells, capacity of maintaining the meristems permanently active and continuous activity of phytohormones. Plant aging usually occurs throughout the whole perennial life, but could be also seasonal senescence. Study of causes for seasonal aging can also help to uncover the mechanisms of plant longevity. The influence of different factors such as microbiome communities, glycation, alternative oxidase activity, mitochondrial dysfunction on plant longevity was also reviewed. Adaptive mechanisms of long-lived plants are considered. Further comparative study of the mechanisms underlying longevity of plants is necessary. This will allow us to reach a potentially new level of understanding of the aging process of plants.
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Proteomic and Phosphoryproteomic Investigations Reveal that Autophagy-Related Protein 1, a Protein Kinase for Autophagy Initiation, Synchronously Deploys Phosphoregulation on the Ubiquitin-Like Conjugation System in the Mycopathogen Beauveria bassiana. mSystems 2022; 7:e0146321. [PMID: 35133188 PMCID: PMC8823290 DOI: 10.1128/msystems.01463-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Autophagy is a conserved intracellular degradation mechanism in eukaryotes and is initiated by the protein kinase autophagy-related protein 1 (Atg1). However, except for the autophosphorylation activity of Atg1, the target proteins phosphorylated by Atg1 are largely unknown in filamentous fungi. In Beauveria bassiana (a filamentous insect-pathogenic fungus), Atg1 is indispensable for autophagy and is associated with fungal development. Comparative omics-based analyses revealed that B. bassiana Atg1 (BbAtg1) has key influence on the proteome and phosphoproteome during conidiogenesis. In terms of its physiological functions, the BbAtg1-mediated phosphoproteome is primarily associated with metabolism, signal transduction, cell cycle, and autophagy. At the proteomic level, BbAtg1 mainly regulates genes involved in protein synthesis, protein fate, and protein with binding function. Furthermore, integrative analyses of phosphoproteomic and proteomic data led to the identification of several potential targets regulated by BbAtg1 phosphorylation activity. Notably, we demonstrated that BbAtg1 phosphorylated BbAtg3, an essential component of the ubiquitin-like conjugation system in autophagic progress. Our findings indicate that in addition to being a critical component of the autophagy initiation, Atg1 orchestrates autophagosome elongation via its phosphorylation activity. The data from our study will facilitate future studies on the noncanonical targets of Atg1 and help decipher the Atg1-mediated phosphorylation networks. IMPORTANCE Autophagy-related protein 1 (Atg1) is a serine/threonine protein kinase for autophagy initiation. In contrast to the unicellular yeast, the target proteins phosphorylated by Atg1 are largely unknown in filamentous fungi. In this study, the entomopathogenic fungus Beauveria bassiana was used as a representative of filamentous fungi due to its importance in the applied and fundamental research. We revealed that Atg1 mediates the comprehensive proteome and phosphoproteome, which differ from those revealed in yeast. Further investigation revealed that Atg1 directly phosphorylates the E2-like enzyme Atg3 of the ubiquitin-like conjugation system (ULCS), and the phosphorylation of Atg3 is indispensable for ULCS functionality. Interestingly, the phosphorylation site of Atg3 is conserved among a set of insect- and plant-pathogenic fungi but not in human-pathogenic fungi. This study reveals new regulatory mechanisms of autophagy and provides new insights into the evolutionary diversity of the Atg1 kinase signaling pathways among different pathogenic fungi.
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8
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Wang H, Ding Z, Gou M, Hu J, Wang Y, Wang L, Wang Y, Di T, Zhang X, Hao X, Wang X, Yang Y, Qian W. Genome-wide identification, characterization, and expression analysis of tea plant autophagy-related genes (CsARGs) demonstrates that they play diverse roles during development and under abiotic stress. BMC Genomics 2021; 22:121. [PMID: 33596831 PMCID: PMC7891152 DOI: 10.1186/s12864-021-07419-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/31/2021] [Indexed: 12/12/2022] Open
Abstract
Background Autophagy, meaning ‘self-eating’, is required for the degradation and recycling of cytoplasmic constituents under stressful and non-stressful conditions, which helps to maintain cellular homeostasis and delay aging and longevity in eukaryotes. To date, the functions of autophagy have been heavily studied in yeast, mammals and model plants, but few studies have focused on economically important crops, especially tea plants (Camellia sinensis). The roles played by autophagy in coping with various environmental stimuli have not been fully elucidated to date. Therefore, investigating the functions of autophagy-related genes in tea plants may help to elucidate the mechanism governing autophagy in response to stresses in woody plants. Results In this study, we identified 35 C. sinensis autophagy-related genes (CsARGs). Each CsARG is highly conserved with its homologues from other plant species, except for CsATG14. Tissue-specific expression analysis demonstrated that the abundances of CsARGs varied across different tissues, but CsATG8c/i showed a degree of tissue specificity. Under hormone and abiotic stress conditions, most CsARGs were upregulated at different time points during the treatment. In addition, the expression levels of 10 CsARGs were higher in the cold-resistant cultivar ‘Longjing43’ than in the cold-susceptible cultivar ‘Damianbai’ during the CA period; however, the expression of CsATG101 showed the opposite tendency. Conclusions We performed a comprehensive bioinformatic and physiological analysis of CsARGs in tea plants, and these results may help to establish a foundation for further research investigating the molecular mechanisms governing autophagy in tea plant growth, development and response to stress. Meanwhile, some CsARGs could serve as putative molecular markers for the breeding of cold-resistant tea plants in future research. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07419-2.
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Affiliation(s)
- Huan Wang
- College of Horticulture, Qingdao Agricultural University, Qingdao, 266109, China
| | - Zhaotang Ding
- College of Horticulture, Qingdao Agricultural University, Qingdao, 266109, China
| | - Mengjie Gou
- College of Horticulture, Qingdao Agricultural University, Qingdao, 266109, China
| | - Jianhui Hu
- College of Horticulture, Qingdao Agricultural University, Qingdao, 266109, China
| | - Yu Wang
- College of Horticulture, Qingdao Agricultural University, Qingdao, 266109, China
| | - Lu Wang
- National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China.,Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou, 310008, China
| | - Yuchun Wang
- College of Agriculture and Food Science, Zhejiang A&F University, Hangzhou, 311300, China
| | - Taimei Di
- National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China.,Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou, 310008, China
| | - Xinfu Zhang
- College of Horticulture, Qingdao Agricultural University, Qingdao, 266109, China
| | - Xinyuan Hao
- National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China.,Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou, 310008, China
| | - Xinchao Wang
- National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China.,Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou, 310008, China
| | - Yajun Yang
- National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China.,Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou, 310008, China
| | - Wenjun Qian
- College of Horticulture, Qingdao Agricultural University, Qingdao, 266109, China.
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Wang X, Song Y, Liu B, Hang W, Li R, Cui H, Li R, Jia X. Enhancement of astaxanthin biosynthesis in Haematococcus pluvialis via inhibition of autophagy by 3-methyladenine under high light. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101991] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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10
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Zhang S, He Y, Sen B, Wang G. Reactive oxygen species and their applications toward enhanced lipid accumulation in oleaginous microorganisms. BIORESOURCE TECHNOLOGY 2020; 307:123234. [PMID: 32245673 DOI: 10.1016/j.biortech.2020.123234] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
Oleaginous microorganisms are among the most promising alternative sources of lipids for oleochemicals and biofuels. However, in the course of lipid production, reactive oxygen species (ROS) are generated inevitably as byproducts of aerobic metabolisms. Although excessive accumulation of ROS leads to lipid peroxidation, DNA damage, and protein denaturation, ROS accumulation has been suggested to enhance lipid synthesis in these microorganisms. There are many unresolved questions concerning this dichotomous view of ROS influence on lipid accumulation. These include what level of ROS triggers lipid overproduction, what mechanisms and targets are vital and whether ROS act as toxic byproducts or cellular messengers in these microorganisms? Here we review the current state of knowledge on ROS generation, antioxidative defense system, the dual effects of ROS on microbial lipid production, and ROS-induced lipid peroxidation and accumulation mechanisms. Toward the end, the review summarizes strategies that enhance lipid production based on ROS manipulation.
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Affiliation(s)
- Sai Zhang
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yaodong He
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Biswarup Sen
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Guangyi Wang
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Qingdao Institute Ocean Engineering of Tianjin University, Qingdao 266237, China.
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11
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Wawrzyńska A, Sirko A. The Role of Selective Protein Degradation in the Regulation of Iron and Sulfur Homeostasis in Plants. Int J Mol Sci 2020; 21:E2771. [PMID: 32316330 PMCID: PMC7215296 DOI: 10.3390/ijms21082771] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/08/2020] [Accepted: 04/14/2020] [Indexed: 02/07/2023] Open
Abstract
Plants are able to synthesize all essential metabolites from minerals, water, and light to complete their life cycle. This plasticity comes at a high energy cost, and therefore, plants need to tightly allocate resources in order to control their economy. Being sessile, plants can only adapt to fluctuating environmental conditions, relying on quality control mechanisms. The remodeling of cellular components plays a crucial role, not only in response to stress, but also in normal plant development. Dynamic protein turnover is ensured through regulated protein synthesis and degradation processes. To effectively target a wide range of proteins for degradation, plants utilize two mechanistically-distinct, but largely complementary systems: the 26S proteasome and the autophagy. As both proteasomal- and autophagy-mediated protein degradation use ubiquitin as an essential signal of substrate recognition, they share ubiquitin conjugation machinery and downstream ubiquitin recognition modules. Recent progress has been made in understanding the cellular homeostasis of iron and sulfur metabolisms individually, and growing evidence indicates that complex crosstalk exists between iron and sulfur networks. In this review, we highlight the latest publications elucidating the role of selective protein degradation in the control of iron and sulfur metabolism during plant development, as well as environmental stresses.
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Affiliation(s)
- Anna Wawrzyńska
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, 02-106 Warsaw, Poland;
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12
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Borek S, Stefaniak S, Śliwiński J, Garnczarska M, Pietrowska-Borek M. Autophagic Machinery of Plant Peroxisomes. Int J Mol Sci 2019; 20:E4754. [PMID: 31557865 PMCID: PMC6802006 DOI: 10.3390/ijms20194754] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 09/22/2019] [Accepted: 09/23/2019] [Indexed: 12/28/2022] Open
Abstract
Peroxisomes are cell organelles that play an important role in plants in many physiological and developmental processes. The plant peroxisomes harbor enzymes of the β-oxidation of fatty acids and the glyoxylate cycle; photorespiration; detoxification of reactive oxygen and nitrogen species; as well as biosynthesis of hormones and signal molecules. The function of peroxisomes in plant cells changes during plant growth and development. They are transformed from organelles involved in storage lipid breakdown during seed germination and seedling growth into leaf peroxisomes involved in photorespiration in green parts of the plant. Additionally, intensive oxidative metabolism of peroxisomes causes damage to their components. Therefore, unnecessary or damaged peroxisomes are degraded by selective autophagy, called pexophagy. This is an important element of the quality control system of peroxisomes in plant cells. Despite the fact that the mechanism of pexophagy has already been described for yeasts and mammals, the molecular mechanisms by which plant cells recognize peroxisomes that will be degraded via pexophagy still remain unclear. It seems that a plant-specific mechanism exists for the selective degradation of peroxisomes. In this review, we describe the physiological role of pexophagy in plant cells and the current hypotheses concerning the mechanism of plant pexophagy.
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Affiliation(s)
- Sławomir Borek
- Department of Plant Physiology, Faculty of Biology, Adam Mickiewicz University Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
| | - Szymon Stefaniak
- Department of Plant Physiology, Faculty of Biology, Adam Mickiewicz University Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
| | - Jan Śliwiński
- Department of Plant Physiology, Faculty of Biology, Adam Mickiewicz University Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
| | - Małgorzata Garnczarska
- Department of Plant Physiology, Faculty of Biology, Adam Mickiewicz University Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
| | - Małgorzata Pietrowska-Borek
- Department of Biochemistry and Biotechnology, Faculty of Agronomy and Bioengineering, Poznań University of Life Sciences, Dojazd 11, 60-632 Poznań, Poland.
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13
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Jiao Y, Srba M, Wang J, Chen W. Correlation of Autophagosome Formation with Degradation and Endocytosis Arabidopsis Regulator of G-Protein Signaling (RGS1) through ATG8a. Int J Mol Sci 2019; 20:ijms20174190. [PMID: 31461856 PMCID: PMC6747245 DOI: 10.3390/ijms20174190] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/20/2019] [Accepted: 08/26/2019] [Indexed: 12/30/2022] Open
Abstract
Damaged or unwanted cellular proteins are degraded by either autophagy or the ubiquitin/proteasome pathway. In Arabidopsis thaliana, sensing of D-glucose is achieved by the heterotrimeric G protein complex and regulator of G-protein signaling 1 (AtRGS1). Here, we showed that starvation increases proteasome-independent AtRGS1 degradation, and it is correlated with increased autophagic flux. RGS1 promoted the production of autophagosomes and autophagic flux; RGS1-yellow fluorescent protein (YFP) was surrounded by vacuolar dye FM4-64 (red fluorescence). RGS1 and autophagosomes co-localized in the root cells of Arabidopsis and BY-2 cells. We demonstrated that the autophagosome marker ATG8a interacts with AtRGS1 and its shorter form with truncation of the seven transmembrane and RGS1 domains in planta. Altogether, our data indicated the correlation of autophagosome formation with degradation and endocytosis of AtRGS1 through ATG8a.
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Affiliation(s)
- Yue Jiao
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China
- College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Miroslav Srba
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12844 Prague, Czech Republic
| | - Jingchun Wang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China
- College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Wenli Chen
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China.
- College of Biophotonics, South China Normal University, Guangzhou 510631, China.
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14
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Lin HY, Wang JJ, Feng MG, Ying SH. Autophagy-related gene ATG7 participates in the asexual development, stress response and virulence of filamentous insect pathogenic fungus Beauveria bassiana. Curr Genet 2019; 65:1015-1024. [PMID: 30879087 DOI: 10.1007/s00294-019-00955-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/06/2019] [Accepted: 03/12/2019] [Indexed: 12/21/2022]
Abstract
Autophagy is a sophisticated mechanism for maintaining cellular homeostasis, in which E1-like enzyme (ATG7) controls the activation of ubiquitin-like conjugation system in the autophagy pathway. In the insect pathogenic fungus Beauveria bassiana, a yeast ortholog of ATG7 was identified and functionally analyzed. Ablation of BbATG7 gene blocks the autophagic process under starvation stress. The mutant ΔBbATG7 exhibited impaired growth on the media with chitin as single nitrogen source. On rich media, gene loss did not cause notable effect on vegetative growth, but resulted in a considerable reduction in conidiation (71.6%) and blastospore yield (61.1%) in the mutant. In addition, the ΔBbATG7 mutant displayed increased sensitivity to stress caused by menadione and Congo red. The virulence of ΔBbATG7 mutant was significantly attenuated as indicated in topical and intrahemocoel injection assays. Our study indicates that BbATG7 contributes to B. bassiana virulence via regulating autophagy pathway and playing non-autophagic functions in the infection cycle.
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Affiliation(s)
- Hai-Yan Lin
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jia-Jia Wang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
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15
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Pottier M, Dumont J, Masclaux-Daubresse C, Thomine S. Autophagy is essential for optimal translocation of iron to seeds in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:859-869. [PMID: 30395253 PMCID: PMC6363094 DOI: 10.1093/jxb/ery388] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/23/2018] [Indexed: 05/18/2023]
Abstract
Micronutrient deficiencies affect a large part of the world's population. These deficiencies are mostly due to the consumption of grains with insufficient content of iron (Fe) or zinc (Zn). Both de novo uptake by roots and recycling from leaves may provide seeds with nutrients. Autophagy, which is a conserved mechanism for nutrient recycling in eukaryotes, was shown to be involved in nitrogen remobilization to seeds. Here, we have investigated the role of this mechanism in micronutrient translocation to seeds. We found that Arabidopsis thaliana plants impaired in autophagy display defects in nutrient remobilization to seeds. In the atg5-1 mutant, which is completely defective in autophagy, the efficiency of Fe translocation from vegetative organs to seeds was severely decreased even when Fe was provided during seed formation. Combining atg5-1 with the sid2 mutation that counteracts premature senescence associated with autophagy deficiency and using 57Fe pulse labeling, we propose a two-step mechanism in which Fe taken up de novo during seed formation is first accumulated in vegetative organs and subsequently remobilized to seeds. Finally, we show that translocation of Zn and manganese (Mn) to seeds is also dependent on autophagy. Fine-tuning autophagy during seed formation opens up new possibilities to improve micronutrient remobilization to seeds.
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Affiliation(s)
- Mathieu Pottier
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
- Present address: InBioS, PhytoSYSTEMS, Laboratory of Plant Physiology, University of Liège, Sart Tilman Campus Quartier Vallée 1, Chemin de la Vallée 4, B-4000, Liège, Belgium
| | - Jean Dumont
- UT2A, Hélioparc Pau Pyrénées, 2, avenue du président Angot, 64053 Pau, France
| | - Céline Masclaux-Daubresse
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Sébastien Thomine
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
- Correspondence:
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16
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Ying SH, Feng MG. Insight into vital role of autophagy in sustaining biological control potential of fungal pathogens against pest insects and nematodes. Virulence 2018; 10:429-437. [PMID: 30257619 PMCID: PMC6550541 DOI: 10.1080/21505594.2018.1518089] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Autophagy is a conserved self-degradation mechanism that governs a large array of cellular processes in filamentous fungi. Filamentous insect and nematode mycopthogens function in the natural control of host populations and have been widely applied for biological control of insect and nematode pests. Entomopathogenic and nematophagous fungi have conserved “core” autophagy machineries that are analogous to those found in yeast but also feature several proteins involved in specific aspects of the autophagic pathways. Here, we review the functions of autophagy in protecting fungal cells from starvation and stress cues and sustaining cell differentiation, asexual development and virulence. An emphasis is placed upon the regulatory mechanisms involved in autophagic and non-autophagic roles of some autophagy-related genes. Methods used for monitoring conserved or specific autophagic events in fungal pathogens are also discussed.
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Affiliation(s)
- Sheng-Hua Ying
- a Institute of Microbiology, College of Life Sciences , Zhejiang University , Hangzhou , China
| | - Ming-Guang Feng
- a Institute of Microbiology, College of Life Sciences , Zhejiang University , Hangzhou , China
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17
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Broda M, Millar AH, Van Aken O. Mitophagy: A Mechanism for Plant Growth and Survival. TRENDS IN PLANT SCIENCE 2018; 23:434-450. [PMID: 29576328 DOI: 10.1016/j.tplants.2018.02.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/13/2018] [Accepted: 02/23/2018] [Indexed: 05/17/2023]
Abstract
Mitophagy is a conserved cellular process that is important for autophagic removal of damaged mitochondria to maintain a healthy mitochondrial population. Mitophagy also appears to occur in plants and has roles in development, stress response, senescence, and programmed cell death. However, many of the genes that control mitophagy in yeast and animal cells are absent from plants, and no plant proteins marking defunct mitochondria for autophagic degradation are yet known. New insights implicate general autophagy-related proteins in mitophagy, affecting the senescence of plant tissues. Mitophagy control and its importance for energy metabolism, survival, signaling, and cell death in plants are discussed. Furthermore, we suggest mitochondrial membrane proteins containing ATG8-interacting motifs, which might serve as mitophagy receptor proteins in plant mitochondria.
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Affiliation(s)
- Martyna Broda
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia, Australia
| | - A Harvey Millar
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia, Australia
| | - Olivier Van Aken
- Department of Biology, Lund University, Sölvegatan 35, 223 62 Lund, Sweden.
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18
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Marion J, Le Bars R, Besse L, Batoko H, Satiat-Jeunemaitre B. Multiscale and Multimodal Approaches to Study Autophagy in Model Plants. Cells 2018; 7:E5. [PMID: 29315263 PMCID: PMC5789278 DOI: 10.3390/cells7010005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 01/05/2018] [Accepted: 01/05/2018] [Indexed: 12/31/2022] Open
Abstract
Autophagy is a catabolic process used by eukaryotic cells to maintain or restore cellular and organismal homeostasis. A better understanding of autophagy in plant biology could lead to an improvement of the recycling processes of plant cells and thus contribute, for example, towards reducing the negative ecological consequences of nitrogen-based fertilizers in agriculture. It may also help to optimize plant adaptation to adverse biotic and abiotic conditions through appropriate plant breeding or genetic engineering to incorporate useful traits in relation to this catabolic pathway. In this review, we describe useful protocols for studying autophagy in the plant cell, taking into account some specificities of the plant model.
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Affiliation(s)
- Jessica Marion
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91 198 Gif-sur-Yvette, France; (J.M.); (R.L.B.); (L.B.); (B.S.-J.)
| | - Romain Le Bars
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91 198 Gif-sur-Yvette, France; (J.M.); (R.L.B.); (L.B.); (B.S.-J.)
| | - Laetitia Besse
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91 198 Gif-sur-Yvette, France; (J.M.); (R.L.B.); (L.B.); (B.S.-J.)
| | - Henri Batoko
- Institute of Life Sciences, UCL/ISV, University of Louvain, Croix du Sud 4, L7.07.14, 1348 Louvain-la-Neuve, Belgium
| | - Béatrice Satiat-Jeunemaitre
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91 198 Gif-sur-Yvette, France; (J.M.); (R.L.B.); (L.B.); (B.S.-J.)
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19
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Demidchik V, Tyutereva EV, Voitsekhovskaja OV. The role of ion disequilibrium in induction of root cell death and autophagy by environmental stresses. FUNCTIONAL PLANT BIOLOGY : FPB 2018; 45:28-46. [PMID: 32291019 DOI: 10.1071/fp16380] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 12/09/2016] [Indexed: 05/26/2023]
Abstract
Environmental stresses such as salinity, drought, oxidants, heavy metals, hypoxia, extreme temperatures and others can induce autophagy and necrosis-type programmed cell death (PCD) in plant roots. These reactions are accompanied by the generation of reactive oxygen species (ROS) and ion disequilibrium, which is induced by electrolyte/K+ leakage through ROS-activated ion channels, such as the outwardly-rectifying K+ channel GORK and non-selective cation channels. Here, we discuss mechanisms of the stress-induced ion disequilibrium and relate it with ROS generation and onset of morphological, biochemical and genetic symptoms of autophagy and PCD in roots. Based on our own data and that in the literature, we propose a hypothesis on the induction of autophagy and PCD in roots by loss of cytosolic K+. To support this, we present data showing that in conditions of salt stress-induced autophagy, gork1-1 plants lacking root K+ efflux channel have fewer autophagosomes compared with the wild type. Overall, literature analyses and presented data strongly suggest that stress-induced root autophagy and PCD are controlled by the level of cytosolic potassium and ROS.
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Affiliation(s)
- Vadim Demidchik
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, ul. Professora Popova 2, 197376St Petersburg, Russia
| | - Elena V Tyutereva
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, ul. Professora Popova 2, 197376St Petersburg, Russia
| | - Olga V Voitsekhovskaja
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, ul. Professora Popova 2, 197376St Petersburg, Russia
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20
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Zhang Z, Sun D, Cheng KW, Chen F. Inhibition of autophagy modulates astaxanthin and total fatty acid biosynthesis in Chlorella zofingiensis under nitrogen starvation. BIORESOURCE TECHNOLOGY 2018; 247:610-615. [PMID: 28985609 DOI: 10.1016/j.biortech.2017.09.133] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/15/2017] [Accepted: 09/19/2017] [Indexed: 05/16/2023]
Abstract
The present study showed that inhibition of autophagy significantly increased cellular levels of reactive oxygen species in Chlorella zofingiensis under nitrogen starvation. This was accompanied with increased expression of PSY, and enhanced accumulation of astaxanthin after 48h of cultivation. Nevertheless, the proportion of astaxanthin in secondary carotenoids remained unchanged. Meanwhile, the expression level of ACCase was also elevated in the 3-MA-treated cells compared to the control despite a >20% lower content of fatty acid in the former than the latter. This phenomenon might be due to inhibition of recycling of cellular components by 3-MA and suggests the potential involvement of post-transcriptional regulation in fatty acid biosynthesis. In summary, our work has been the first to report a potentially important role of autophagy in fatty acid and astaxanthin accumulation in C. zofingiensis under stress conditions. The findings might provide valuable insights to guide further research in this area.
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Affiliation(s)
- Zhao Zhang
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing 100871, China; BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Dongzhe Sun
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Ka-Wing Cheng
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Feng Chen
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing 100871, China; BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China.
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21
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Zientara-Rytter K, Sirko A. To deliver or to degrade - an interplay of the ubiquitin-proteasome system, autophagy and vesicular transport in plants. FEBS J 2017; 283:3534-3555. [PMID: 26991113 DOI: 10.1111/febs.13712] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 02/21/2016] [Accepted: 03/14/2016] [Indexed: 12/21/2022]
Abstract
The efficient utilization and subsequent reuse of cell components is a key factor in determining the proper growth and functioning of all cells under both optimum and stress conditions. The process of intracellular and intercellular recycling is especially important for the appropriate control of cellular metabolism and nutrient management in immobile organisms, such as plants. Therefore, the accurate recycling of amino acids, lipids, carbohydrates or micro- and macronutrients available in the plant cell becomes a critical factor that ensures plant survival and growth. Plant cells possess two main degradation mechanisms: a ubiquitin-proteasome system and autophagy, which, as a part of an intracellular trafficking system, is based on vesicle transport. This review summarizes knowledge of both the ubiquitin-proteasome system and autophagy pathways, describes the cross-talk between the two and discusses the relationships between autophagy and the vesicular transport systems.
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Affiliation(s)
| | - Agnieszka Sirko
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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22
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Reumann S, Chowdhary G, Lingner T. Characterization, prediction and evolution of plant peroxisomal targeting signals type 1 (PTS1s). BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1863:790-803. [PMID: 26772785 DOI: 10.1016/j.bbamcr.2016.01.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 01/01/2016] [Accepted: 01/04/2016] [Indexed: 12/22/2022]
Abstract
Our knowledge of the proteome of plant peroxisomes and their functional plasticity is far from being complete, primarily due to major technical challenges in experimental proteome research of the fragile cell organelle. Several unexpected novel plant peroxisome functions, for instance in biotin and phylloquinone biosynthesis, have been uncovered recently. Nevertheless, very few regulatory and membrane proteins of plant peroxisomes have been identified and functionally described up to now. To define the matrix proteome of plant peroxisomes, computational methods have emerged as important powerful tools. Novel prediction approaches of high sensitivity and specificity have been developed for peroxisome targeting signals type 1 (PTS1) and have been validated by in vivo subcellular targeting analyses and thermodynamic binding studies with the cytosolic receptor, PEX5. Accordingly, the algorithms allow the correct prediction of many novel peroxisome-targeted proteins from plant genome sequences and the discovery of additional organelle functions. In this review, we provide an overview of methodologies, capabilities and accuracies of available prediction algorithms for PTS1 carrying proteins. We also summarize and discuss recent quantitative, structural and mechanistic information of the interaction of PEX5 with PTS1 carrying proteins in relation to in vivo import efficiency. With this knowledge, we develop a model of how proteins likely evolved peroxisomal targeting signals in the past and still nowadays, in which order the two import pathways might have evolved in the ancient eukaryotic cell, and how the secondary loss of the PTS2 pathway probably happened in specific organismal groups.
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Affiliation(s)
- S Reumann
- Department of Plant Biochemistry and Infection Biology, Biocentre Klein Flottbek, University of Hamburg, D-22609 Hamburg, Germany; Centre for Organelle Research, University of Stavanger, N-4036 Stavanger, Norway.
| | - G Chowdhary
- Centre for Organelle Research, University of Stavanger, N-4036 Stavanger, Norway; KIIT School of Biotechnology, Campus XI, KIIT University, I-751024 Bhubaneswar, India.
| | - T Lingner
- Department of Bioinformatics, Institute for Microbiology and Genetics, D-37077 Goettingen, Germany.
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23
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Voitsekhovskaja OV, Tyutereva EV. Chlorophyll b in angiosperms: Functions in photosynthesis, signaling and ontogenetic regulation. JOURNAL OF PLANT PHYSIOLOGY 2015; 189:51-64. [PMID: 26513460 DOI: 10.1016/j.jplph.2015.09.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 05/22/2023]
Abstract
Chlorophyll b (Chlb) is an antenna chlorophyll. The binding of Chlb by antenna proteins is crucial for the correct assembly of the antenna complexes in thylakoid membranes. Since the levels of the proteins of major and minor antenna are affected to different extents by Chlb binding, the availability of Chlb influences the composition and the size of antenna complexes which in turn determine the supramolecular organization of the thylakoid membranes in grana. Therefore, Chlb synthesis levels have a major impact on lateral mobility and diffusion of membrane molecules, and thus affect not only light harvesting and thermal energy dissipation processes, but also linear electron transport and repair processes in grana. Furthermore, in angiosperms Chlb synthesis affects plant functions beyond chloroplasts. First, the stability of pigment-protein complexes in the antennae, which depends on Chlb, is an important factor in the regulation of plant ontogenesis, and Chlb levels were recently shown to influence plant ontogenetic signaling. Second, the amounts of minor antenna proteins in chloroplasts, which depend on the availability of Chlb, were recently shown to affect ABA levels and signaling in plants. These mechanisms can be examined in mutants where Chlb synthesis is reduced or abolished. The dramatic effects caused by the lack of Chlb on plant productivity are interpreted in this review in light of the pleiotropic effects on photosynthesis and signaling, and the potential to manipulate Chlb biosynthesis for the improvement of crop production is discussed.
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Affiliation(s)
- O V Voitsekhovskaja
- Komarov Botanical Institute, Russian Academy of Sciences, Plant Ecological Physiology, ul. Professora Popova, 2, 197376 St. Petersburg, Russia.
| | - E V Tyutereva
- Komarov Botanical Institute, Russian Academy of Sciences, Plant Ecological Physiology, ul. Professora Popova, 2, 197376 St. Petersburg, Russia
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24
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Avin-Wittenberg T, Bajdzienko K, Wittenberg G, Alseekh S, Tohge T, Bock R, Giavalisco P, Fernie AR. Global analysis of the role of autophagy in cellular metabolism and energy homeostasis in Arabidopsis seedlings under carbon starvation. THE PLANT CELL 2015; 27:306-22. [PMID: 25649436 PMCID: PMC4456922 DOI: 10.1105/tpc.114.134205] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/29/2014] [Accepted: 01/19/2015] [Indexed: 05/18/2023]
Abstract
Germination and early seedling establishment are developmental stages in which plants face limited nutrient supply as their photosynthesis mechanism is not yet active. For this reason, the plant must mobilize the nutrient reserves provided by the mother plant in order to facilitate growth. Autophagy is a catabolic process enabling the bulk degradation of cellular constituents in the vacuole. The autophagy mechanism is conserved among eukaryotes, and homologs of many autophagy-related (ATG) genes have been found in Arabidopsis thaliana. T-DNA insertion mutants (atg mutants) of these genes display higher sensitivity to various stresses, particularly nutrient starvation. However, the direct impact of autophagy on cellular metabolism has not been well studied. In this work, we used etiolated Arabidopsis seedlings as a model system for carbon starvation. atg mutant seedlings display delayed growth in response to carbon starvation compared with wild-type seedlings. High-throughput metabolomic, lipidomic, and proteomic analyses were performed, as well as extensive flux analyses, in order to decipher the underlying causes of the phenotype. Significant differences between atg mutants and wild-type plants have been demonstrated, suggesting global effects of autophagy on central metabolism during carbon starvation as well as severe energy deprivation, resulting in a morphological phenotype.
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Affiliation(s)
| | - Krzysztof Bajdzienko
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany
| | - Gal Wittenberg
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany
| | - Saleh Alseekh
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany
| | - Takayuki Tohge
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany
| | - Patrick Giavalisco
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany
| | - Alisdair R Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany
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25
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Voitsekhovskaja OV, Schiermeyer A, Reumann S. Plant peroxisomes are degraded by starvation-induced and constitutive autophagy in tobacco BY-2 suspension-cultured cells. FRONTIERS IN PLANT SCIENCE 2014; 5:629. [PMID: 25477890 PMCID: PMC4235271 DOI: 10.3389/fpls.2014.00629] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/23/2014] [Indexed: 05/07/2023]
Abstract
Very recently, autophagy has been recognized as an important degradation pathway for quality control of peroxisomes in Arabidopsis plants. To further characterize the role of autophagy in plant peroxisome degradation, we generated stable transgenic suspension-cultured cell lines of heterotrophic Nicotiana tabacum L. cv. Bright Yellow 2 expressing a peroxisome-targeted version of enhanced yellow fluorescent protein. Indeed, this cell line model system proved advantageous for detailed cytological analyses of autophagy stages and for quantification of cellular peroxisome pools under different culturing conditions and upon inhibitor applications. Complementary biochemical, cytological, and pharmacological analyses provided convincing evidence for peroxisome degradation by bulk autophagy during carbohydrate starvation. This degradation was slowed down by the inhibitor of autophagy, 3-methyladenine (3-MA), but the 3-MA effect ceased at advanced stages of starvation, indicating that another degradation mechanism for peroxisomes might have taken over. 3-MA also caused an increase particularly in peroxisomal proteins and cellular peroxisome numbers when applied under nutrient-rich conditions in the logarithmic growth phase, suggesting a high turnover rate for peroxisomes by basal autophagy under non-stress conditions. Together, our data demonstrate that a great fraction of the peroxisome pool is subject to extensive autophagy-mediated turnover under both nutrient starvation and optimal growth conditions. Our analyses of the cellular pool size of peroxisomes provide a new tool for quantitative investigations of the role of plant peroxisomes in reactive oxygen species metabolism.
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Affiliation(s)
- Olga V. Voitsekhovskaja
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität GöttingenGöttingen, Germany
- Komarov Botanical Institute, Russian Academy of Sciences, Laboratory of Plant Ecological PhysiologySaint Petersburg, Russia
| | - Andreas Schiermeyer
- Abteilung Pflanzenbiotechnologie, Fraunhofer-Institut für Molekularbiologie und Angewandte OekologieAachen, Germany
| | - Sigrun Reumann
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität GöttingenGöttingen, Germany
- Institute for Mathematics and Natural Sciences, Faculty of Science and Technology, Centre for Organelle Research, University of StavangerStavanger, Norway
- Faculty of Mathematics, Informatics and Natural Sciences, Biocentre Klein Flottbek, University of HamburgHamburg, Germany
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26
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Sakuraba Y, Lee SH, Kim YS, Park OK, Hörtensteiner S, Paek NC. Delayed degradation of chlorophylls and photosynthetic proteins in Arabidopsis autophagy mutants during stress-induced leaf yellowing. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3915-25. [PMID: 24510943 PMCID: PMC4106435 DOI: 10.1093/jxb/eru008] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plant autophagy, one of the essential proteolysis systems, balances proteome and nutrient levels in cells of the whole plant. Autophagy has been studied by analysing Arabidopsis thaliana autophagy-defective atg mutants, but the relationship between autophagy and chlorophyll (Chl) breakdown during stress-induced leaf yellowing remains unclear. During natural senescence or under abiotic-stress conditions, extensive cell death and early yellowing occurs in the leaves of atg mutants. A new finding is revealed that atg5 and atg7 mutants exhibit a functional stay-green phenotype under mild abiotic-stress conditions, but leaf yellowing proceeds normally in wild-type leaves under these conditions. Under mild salt stress, atg5 leaves retained high levels of Chls and all photosystem proteins and maintained a normal chloroplast structure. Furthermore, a double mutant of atg5 and non-functional stay-green nonyellowing1-1 (atg5 nye1-1) showed a much stronger stay-green phenotype than either single mutant. Taking these results together, it is proposed that autophagy functions in the non-selective catabolism of Chls and photosynthetic proteins during stress-induced leaf yellowing, in addition to the selective degradation of Chl-apoprotein complexes in the chloroplasts through the senescence-induced STAY-GREEN1/NYE1 and Chl catabolic enzymes.
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Affiliation(s)
- Yasuhito Sakuraba
- Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
| | - Sang-Hwa Lee
- Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
| | - Ye-Sol Kim
- Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
| | - Ohkmae K Park
- Department of Life Sciences, Korea University, Seoul 136-701, Korea
| | | | - Nam-Chon Paek
- Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
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Morita MT, Shimada T. The Plant Endomembrane System—A Complex Network Supporting Plant Development and Physiology. ACTA ACUST UNITED AC 2014; 55:667-71. [DOI: 10.1093/pcp/pcu049] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Merkulova EA, Guiboileau A, Naya L, Masclaux-Daubresse C, Yoshimoto K. Assessment and optimization of autophagy monitoring methods in Arabidopsis roots indicate direct fusion of autophagosomes with vacuoles. PLANT & CELL PHYSIOLOGY 2014; 55:715-26. [PMID: 24566535 DOI: 10.1093/pcp/pcu041] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Autophagy is a degradation pathway that recycles cell materials upon encountering stress conditions or during specific developmental processes. To better understand the physiological roles of autophagy, proper monitoring methods are very important. In mammals and yeast, monitoring of autophagy is often performed with a green fluorescent protein (GFP)-ATG8 fusion protein or with acidotropic dyes such as monodansylcadaverine (MDC) and LysoTracker Red (LTR). To evaluate these monitoring methods, here we examined these systems by inducing autophagy in Arabidopsis thaliana roots as a model for monitoring autophagy in planta. Under carbon- and nitrogen-starved conditions, the number and size of vesicles labeled by GFP-ATG8 was increased for several hours and then gradually decreased to a level higher than that observed before the start of the experiment. We also observed the disappearance of GFP-ATG8-labeled vesicles after treatment with wortmannin, a phosphatidylinositol 3-kinase inhibitor known as an autophagy inhibitor, showing that the GFP-ATG8 transgenic line constitutes an excellent method for monitoring autophagy. These data were compared with plants stained with MDC and LTR. There was no appreciable MDC/LTR staining of small organelles in the root under the induction of autophagy. Some vesicles were eventually observed in the root tip only, but co-localization experiments, as well as experiments with autophagy-deficient atg mutants, provided the evidence that these structures were located in the vacuole and were not manifestly autophagosomes and/or autolysosomes. Extreme caution should therefore be used when monitoring autophagy with the aid of MDC/LTR. Additionally, our observations strongly suggest that autophagosomes fuse directly to vacuoles in Arabidopsis roots.
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Ishida H, Izumi M, Wada S, Makino A. Roles of autophagy in chloroplast recycling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:512-21. [PMID: 24269172 DOI: 10.1016/j.bbabio.2013.11.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/01/2013] [Accepted: 11/07/2013] [Indexed: 01/04/2023]
Abstract
Chloroplasts are the primary energy suppliers for plants, and much of the total leaf nitrogen is distributed to these organelles. During growth and reproduction, chloroplasts in turn represent a major source of nitrogen to be recovered from senescing leaves and used in newly-forming and storage organs. Chloroplast proteins also can be an alternative substrate for respiration under suboptimal conditions. Autophagy is a process of bulk degradation and nutrient sequestration that is conserved in all eukaryotes. Autophagy can selectively target chloroplasts as whole organelles and or as Rubisco-containing bodies that are enclosed by the envelope and specifically contain the stromal portion of the chloroplast. Although information is still limited, recent work indicates that chloroplast recycling via autophagy plays important roles not only in developmental processes but also in organelle quality control and adaptation to changing environments. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
- Hiroyuki Ishida
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
| | - Masanori Izumi
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Shinya Wada
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
| | - Amane Makino
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
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Farmer LM, Rinaldi MA, Young PG, Danan CH, Burkhart SE, Bartel B. Disrupting autophagy restores peroxisome function to an Arabidopsis lon2 mutant and reveals a role for the LON2 protease in peroxisomal matrix protein degradation. THE PLANT CELL 2013; 25:4085-100. [PMID: 24179123 PMCID: PMC3877801 DOI: 10.1105/tpc.113.113407] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 09/09/2013] [Accepted: 10/08/2013] [Indexed: 05/18/2023]
Abstract
Peroxisomes house critical metabolic reactions that are essential for seedling development. As seedlings mature, metabolic requirements change, and peroxisomal contents are remodeled. The resident peroxisomal protease LON2 is positioned to degrade obsolete or damaged peroxisomal proteins, but data supporting such a role in plants have remained elusive. Arabidopsis thaliana lon2 mutants display defects in peroxisomal metabolism and matrix protein import but appear to degrade matrix proteins normally. To elucidate LON2 functions, we executed a forward-genetic screen for lon2 suppressors, which revealed multiple mutations in key autophagy genes. Disabling core autophagy-related gene (ATG) products prevents autophagy, a process through which cytosolic constituents, including organelles, can be targeted for vacuolar degradation. We found that atg2, atg3, and atg7 mutations suppressed lon2 defects in auxin metabolism and matrix protein processing and rescued the abnormally large size and small number of lon2 peroxisomes. Moreover, analysis of lon2 atg mutants uncovered an apparent role for LON2 in matrix protein turnover. Our data suggest that LON2 facilitates matrix protein degradation during peroxisome content remodeling, provide evidence for the existence of pexophagy in plants, and indicate that peroxisome destruction via autophagy is enhanced when LON2 is absent.
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Zhang L, Wang J, Xie XQ, Keyhani NO, Feng MG, Ying SH. The autophagy gene BbATG5, involved in the formation of the autophagosome, contributes to cell differentiation and growth but is dispensable for pathogenesis in the entomopathogenic fungus Beauveria bassiana. Microbiology (Reading) 2013. [DOI: 10.1099/mic.0.062646-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Lei Zhang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, PR China
| | - Jie Wang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, PR China
| | - Xue-Qin Xie
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, PR China
| | - Nemat O. Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, PR China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, PR China
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Kim SH, Kwon C, Lee JH, Chung T. Genes for plant autophagy: functions and interactions. Mol Cells 2012; 34:413-23. [PMID: 22772908 PMCID: PMC3887786 DOI: 10.1007/s10059-012-0098-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/22/2012] [Accepted: 05/23/2012] [Indexed: 12/21/2022] Open
Abstract
Autophagy, or self-consuming of cytoplasmic constituents in a lytic compartment, plays a crucial role in nutrient recycling, development, cell homeostasis, and defense against pathogens and toxic products. Autophagy in plant cells uses a conserved machinery of core Autophagy-related (Atg) proteins. Recently, research on plant autophagy has been expanding and other components interacting with the core Atg proteins are being revealed. In addition, growing evidence suggests that autophagy communicates with other cellular pathways such as the ubiquitin-proteasome system, protein secretory pathway, and endocytic pathway. An increase in our understanding of plant autophagy will undoubtedly help test the hypothesized functions of plant autophagy in programmed cell death, vacuole biogenesis, and responses to biotic, abiotic, and nutritional stresses. In this review, we summarize recent progress on these topics and suggest topics for future research, after inspecting common phenotypes of current Arabidopsis atg mutants.
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Affiliation(s)
- Soon-Hee Kim
- Department of Biological Sciences, Pusan National University, Busan 609-735,
Korea
| | | | | | - Taijoon Chung
- Department of Biological Sciences, Pusan National University, Busan 609-735,
Korea
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33
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Akpinar BA, Avsar B, Lucas SJ, Budak H. Plant abiotic stress signaling. PLANT SIGNALING & BEHAVIOR 2012; 7:1450-5. [PMID: 22990453 PMCID: PMC3548870 DOI: 10.4161/psb.21894] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Stress signaling is central to plants which--as immobile organisms--have to endure environmental fluctuations that constantly interfere with vigorous growth. As a result, plant-specific, elaborate mechanisms have evolved to perceive and respond to stress conditions. Currently, these stress responses are plausibly being revealed to involve crosstalks with energy signaling pathways as any growth-limiting factor alters plant's energy status. Among these, autophagy, conventionally regarded as the mechanism whereby plants recycle and remobilize nutrients in bulk, has frequently been associated with stress responses. With the recent discoveries, however, autophagy has attained a novel role in stress signaling. In this review, major elements of abitoic stress signaling are summarized along with autophagy pathway, and in the light of recent discoveries, a putative, state-of-art role of autophagy is discussed.
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34
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Minibayeva F, Dmitrieva S, Ponomareva A, Ryabovol V. Oxidative stress-induced autophagy in plants: the role of mitochondria. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 59:11-9. [PMID: 22386760 DOI: 10.1016/j.plaphy.2012.02.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 02/09/2012] [Indexed: 05/08/2023]
Abstract
The strictly regulated removal of oxidized structures is a universal stress response of eukaryotic cells that targets damaged or toxic components for vacuolar or lysosomal degradation. Autophagy stands at the crossroad between cell survival and death. It promotes survival by degrading proteins and organelles damaged during oxidative stress, but it is also activated as a part of death programs, when the damage cannot be overcome. Evidence is accumulating that the cellular sites of ROS production and signaling may be primary targets of autophagy. Therefore, autophagosomal targeting of mitochondria (mitophagy) is of particular importance. Mitophagy is a selective process that can specifically target dysfunctional mitochondria, but also mitophagy may play a role in controlling the number and quality of mitochondria during stress. Here we review the mechanisms of both non-specific autophagy and mitochondrial targeting in plants, drawing analogies and emphasizing differences with yeast and mammalian systems.
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Affiliation(s)
- Farida Minibayeva
- Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, PO Box 30, Kazan 420111, Russian Federation.
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35
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Jiang Q, Zhao L, Dai J, Wu Q. Analysis of autophagy genes in microalgae: Chlorella as a potential model to study mechanism of autophagy. PLoS One 2012; 7:e41826. [PMID: 22848622 PMCID: PMC3407069 DOI: 10.1371/journal.pone.0041826] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 06/26/2012] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Microalgae, with the ability to mitigate CO(2) emission and produce carbohydrates and lipids, are considered one of the most promising resources for producing bioenergy. Recently, we discovered that autophagy plays a critical role in the metabolism of photosynthetic system and lipids production. So far, more than 30-autophagy related (ATG) genes in all subtypes of autophagy have been identified. However, compared with yeast and mammals, in silico and experimental research of autophagy pathways in microalgae remained limited and fragmentary. PRINCIPAL FINDINGS In this article, we performed a genome-wide analysis of ATG genes in 7 microalgae species and explored their distributions, domain structures and evolution. Eighteen "core autophagy machinery" proteins, four mammalian-specific ATG proteins and more than 30 additional proteins (including "receptor-adaptor" complexes) in all subtypes of autophagy were analyzed. Data revealed that receptor proteins in cytoplasm-to-vacuole targeting and mitophagy seem to be absent in microalgae. However, most of the "core autophagy machinery" and mammalian-specific proteins are conserved among microalgae, except for the ATG9-cycling system in Chlamydomonas reinhardtii and the second ubiquitin-like protein conjugation complex in several algal species. The catalytic and binding residues in ATG3, ATG5, ATG7, ATG8, ATG10 and ATG12 are also conserved and the phylogenetic tree of ATG8 coincides well with the phylogenies. Chlorella contains the entire set of the core autophagy machinery. In addition, RT-PCR analysis verified that all crucial ATG genes tested are expressed during autophagy in both Chlorella and Chlamydomonas reinhardtii. Finally, we discovered that addition of 3-Methyladenine (a PI3K specific inhibitor) could suppress the formation of autophagic vacuoles in Chlorella. CONCLUSIONS Taken together, Chlorella may represent a potential model organism to investigate autophagy pathways in photosynthetic eukaryotes. The study will not only promote understanding of the general features of autophagic pathways, but also benefit the production of Chlorella-derived biofuel with future commercial applications.
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Affiliation(s)
- Qiao Jiang
- MOE Key Laboratory of Bioinformatics and Center for Epigenetics and Chromatin, School of Life Sciences, Tsinghua University, Beijing, China
| | - Li Zhao
- MOE Key Laboratory of Bioinformatics and Center for Epigenetics and Chromatin, School of Life Sciences, Tsinghua University, Beijing, China
| | - Junbiao Dai
- MOE Key Laboratory of Bioinformatics and Center for Epigenetics and Chromatin, School of Life Sciences, Tsinghua University, Beijing, China
- * E-mail: (JD); (QW)
| | - Qingyu Wu
- MOE Key Laboratory of Bioinformatics and Center for Epigenetics and Chromatin, School of Life Sciences, Tsinghua University, Beijing, China
- * E-mail: (JD); (QW)
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36
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Guiboileau A, Masclaux-Daubresse C. L’autophagie chez les plantes : mécanismes, régulations et fonctions. C R Biol 2012; 335:375-88. [DOI: 10.1016/j.crvi.2012.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/13/2012] [Accepted: 04/14/2012] [Indexed: 12/20/2022]
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37
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Guiboileau A, Yoshimoto K, Soulay F, Bataillé MP, Avice JC, Masclaux-Daubresse C. Autophagy machinery controls nitrogen remobilization at the whole-plant level under both limiting and ample nitrate conditions in Arabidopsis. THE NEW PHYTOLOGIST 2012; 194:732-740. [PMID: 22404536 DOI: 10.1111/j.1469-8137.2012.04084.x] [Citation(s) in RCA: 173] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
• Processes allowing the recycling of organic nitrogen and export to young leaves and seeds are important determinants of plant yield, especially when plants are nitrate-limited. Because autophagy is induced during leaf ageing and in response to nitrogen starvation, its role in nitrogen remobilization was suspected. It was recently shown that autophagy participates in the trafficking of Rubisco-containing bodies to the vacuole. • To investigate the role of autophagy in nitrogen remobilization, several autophagy-defective (atg) Arabidopsis mutants were grown under low and high nitrate supplies and labeled with at the vegetative stage in order to determine (15) N partitioning in seeds at harvest. Because atg mutants displayed earlier and more rapid leaf senescence than wild type, we investigated whether their defects in nitrogen remobilization were related to premature leaf cell death by studying the stay-green atg5.sid2 and atg5.NahG mutants. • Results showed that nitrogen remobilization efficiency was significantly lower in all the atg mutants irrespective of biomass defects, harvest index reduction, leaf senescence phenotypes and nitrogen conditions. • We conclude that autophagy core machinery is needed for nitrogen remobilization and seed filling.
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Affiliation(s)
- Anne Guiboileau
- INRA, UMR1318, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Kohki Yoshimoto
- INRA, UMR1318, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
- RIKEN, Plant Science Center, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Fabienne Soulay
- INRA, UMR1318, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Marie-Paule Bataillé
- INRA, UMR INRA-UCBN 950, Ecophysiologie Végétale, Agronomie et Nutritions N, C, S, Université de Caen, 14000 Caen, France
| | - Jean-Christophe Avice
- INRA, UMR INRA-UCBN 950, Ecophysiologie Végétale, Agronomie et Nutritions N, C, S, Université de Caen, 14000 Caen, France
| | - Céline Masclaux-Daubresse
- INRA, UMR1318, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
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38
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Avin-Wittenberg T, Honig A, Galili G. Variations on a theme: plant autophagy in comparison to yeast and mammals. PROTOPLASMA 2012; 249:285-99. [PMID: 21660427 DOI: 10.1007/s00709-011-0296-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 05/22/2011] [Indexed: 05/18/2023]
Abstract
Autophagy is an evolutionary conserved process of bulk degradation and nutrient sequestration that occurs in all eukaryotic cells. Yet, in recent years, autophagy has also been shown to play a role in the specific degradation of individual proteins or protein aggregates as well as of damaged organelles. The process was initially discovered in yeast and has also been very well studied in mammals and, to a lesser extent, in plants. In this review, we summarize what is known regarding the various functions of autopahgy in plants but also attempt to address some specific issues concerning plant autophagy, such as the insufficient knowledge regarding autophagy in various plant species other than Arabidopsis, the fact that some genes belonging to the core autophagy machinery in various organisms are still missing in plants, the existence of autophagy multigene families in plants and the possible operation of selective autophagy in plants, a study that is still in its infancy. In addition, we point to plant-specific autophagy processes, such as the participation of autophagy during development and germination of the seed, a unique plant organ. Throughout this review, we demonstrate that the use of innovative bioinformatic resources, together with recent biological discoveries (such as the ATG8-interacting motif), should pave the way to a more comprehensive understanding of the multiple functions of plant autophagy.
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Abstract
Plants have developed sophisticated mechanisms to survive when in unfavorable environments. Autophagy is a macromolecule degradation pathway that recycles damaged or unwanted cell materials upon encountering stress conditions or during specific developmental processes. Over the past decade, our molecular and physiological understanding of plant autophagy has greatly increased. Most of the essential machinery required for autophagy seems to be conserved from yeast to plants. Plant autophagy has been shown to function in various stress responses, pathogen defense, and senescence. Some of its potential upstream regulators have also been identified. Here, we describe recent advances in our understanding of autophagy in plants, discuss areas of controversy, and highlight potential future directions in autophagy research.
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Affiliation(s)
- Yimo Liu
- Department of Genetics, Development, and Cell Biology and Interdepartmental Genetics Program, Iowa State University, Ames, IA 50011, USA
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40
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Jiao BB, Wang JJ, Zhu XD, Zeng LJ, Li Q, He ZH. A novel protein RLS1 with NB-ARM domains is involved in chloroplast degradation during leaf senescence in rice. MOLECULAR PLANT 2012; 5:205-17. [PMID: 21980143 DOI: 10.1093/mp/ssr081] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Leaf senescence, a type of programmed cell death (PCD) characterized by chlorophyll degradation, is important to plant growth and crop productivity. It emerges that autophagy is involved in chloroplast degradation during leaf senescence. However, the molecular mechanism(s) involved in the process is not well understood. In this study, the genetic and physiological characteristics of the rice rls1 (rapid leaf senescence 1) mutant were identified. The rls1 mutant developed small, yellow-brown lesions resembling disease scattered over the whole surfaces of leaves that displayed earlier senescence than those of wild-type plants. The rapid loss of chlorophyll content during senescence was the main cause of accelerated leaf senescence in rls1. Microscopic observation indicated that PCD was misregulated, probably resulting in the accelerated degradation of chloroplasts in rls1 leaves. Map-based cloning of the RLS1 gene revealed that it encodes a previously uncharacterized NB (nucleotide-binding site)-containing protein with an ARM (armadillo) domain at the carboxyl terminus. Consistent with its involvement in leaf senescence, RLS1 was up-regulated during dark-induced leaf senescence and down-regulated by cytokinin. Intriguingly, constitutive expression of RLS1 also slightly accelerated leaf senescence with decreased chlorophyll content in transgenic rice plants. Our study identified a previously uncharacterized NB-ARM protein involved in PCD during plant growth and development, providing a unique tool for dissecting possible autophagy-mediated PCD during senescence in plants.
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Affiliation(s)
- Bin-Bin Jiao
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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41
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Zientara-Rytter K, Lukomska J, Moniuszko G, Gwozdecki R, Surowiecki P, Lewandowska M, Liszewska F, Wawrzyńska A, Sirko A. Identification and functional analysis of Joka2, a tobacco member of the family of selective autophagy cargo receptors. Autophagy 2011; 7:1145-58. [PMID: 21670587 PMCID: PMC3242614 DOI: 10.4161/auto.7.10.16617] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 05/26/2011] [Accepted: 05/27/2011] [Indexed: 12/27/2022] Open
Abstract
Two main mechanisms of protein turnover exist in eukaryotic cells: the ubiquitin-proteasome system and the autophagy-lysosomal pathway. Autophagy is an emerging important constituent of many physiological and pathological processes, such as response to nutrient deficiency, programmed cell death and innate immune response. In mammalian cells the selectivity of autophagy is ensured by the presence of cargo receptors, such as p62/SQSTM1 and NBR1, responsible for sequestration of the ubiquitinated proteins. In plants no selective cargo receptors have been identified yet. The present report indicates that structural and functional homologs of p62 and NBR1 proteins exist in plants. The tobacco protein, named Joka2, has been identified in yeast two-hybrid search as a binding partner of a small coiled-coil protein, a member of UP9/LSU family of unknown function, encoded by the UP9C gene strongly and specifically induced during sulfur deficiency. The typical domains of p62 and NBR1 are conserved in Joka2. Similarly to p62, Joka2-YFP has dual localization (cytosolic speckles and the nucleus); it forms homodimers and interacts with a member of the ATG8 family. Increased expression of Joka2 and ATG8f was observed in roots of tobacco plants grown for two days in nutrient-deficient conditions. Constitutive ectopic expression of Joka2-YFP in tobacco resulted in attenuated response (manifested by lesser yellowing of the leaves) to nutrient deficiency. In conclusion, Joka2, and presumably the process of selective autophagy, might constitute an important part of plant response to environmental stresses.
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42
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Hayward AP, Dinesh-Kumar SP. What can plant autophagy do for an innate immune response? ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:557-76. [PMID: 21370973 DOI: 10.1146/annurev-phyto-072910-095333] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Autophagy plays an established role in the execution of senescence, starvation, and stress responses in plants. More recently, an emerging role for autophagy has been discovered during the plant innate immune response. Recent papers have shown autophagy to restrict, and conversely, to also promote programmed cell death (PCD) at the site of pathogen infection. These initial studies have piqued our excitement, but they have also revealed gaps in our understanding of plant autophagy regulation, in our ability to monitor autophagy in plant cells, and in our ability to manipulate autophagic activity. In this review, we present the most pressing questions now facing the field of plant autophagy in general, with specific focus on autophagy as it occurs during a plant-pathogen interaction. To begin to answer these questions, we place recent findings in the context of studies of autophagy and immunity in other systems, and in the context of the mammalian immune response in particular.
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Affiliation(s)
- Andrew P Hayward
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
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