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Negroni YL, Doro I, Tamborrino A, Luzzi I, Fortunato S, Hensel G, Khosravi S, Maretto L, Stevanato P, Lo Schiavo F, de Pinto MC, Krupinska K, Zottini M. The Arabidopsis Mitochondrial Nucleoid-Associated Protein WHIRLY2 Is Required for a Proper Response to Salt Stress. PLANT & CELL PHYSIOLOGY 2024; 65:576-589. [PMID: 38591870 PMCID: PMC11094760 DOI: 10.1093/pcp/pcae025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 03/04/2024] [Accepted: 03/07/2024] [Indexed: 04/10/2024]
Abstract
In the last years, plant organelles have emerged as central coordinators of responses to internal and external stimuli, which can induce stress. Mitochondria play a fundamental role as stress sensors being part of a complex communication network between the organelles and the nucleus. Among the different environmental stresses, salt stress poses a significant challenge and requires efficient signaling and protective mechanisms. By using the why2 T-DNA insertion mutant and a novel knock-out mutant prepared by CRISPR/Cas9-mediated genome editing, this study revealed that WHIRLY2 is crucial for protecting mitochondrial DNA (mtDNA) integrity during salt stress. Loss-of-function mutants show an enhanced sensitivity to salt stress. The disruption of WHIRLY2 causes the impairment of mtDNA repair that results in the accumulation of aberrant recombination products, coinciding with severe alterations in nucleoid integrity and overall mitochondria morphology besides a compromised redox-dependent response and misregulation of antioxidant enzymes. The results of this study revealed that WHIRLY2-mediated structural features in mitochondria (nucleoid compactness and cristae) are important for an effective response to salt stress.
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Affiliation(s)
- Yuri L Negroni
- Department of Biology, University of Padova, Via U. Bassi 58/b, Padova 35131, Italy
| | - Irene Doro
- Department of Biology, University of Padova, Via U. Bassi 58/b, Padova 35131, Italy
| | - Alberto Tamborrino
- Department of Biology, University of Padova, Via U. Bassi 58/b, Padova 35131, Italy
| | - Irene Luzzi
- Department of Biology, University of Padova, Via U. Bassi 58/b, Padova 35131, Italy
| | - Stefania Fortunato
- Department of Biosciences, Biotechnology and Environment, University of Bari, Campus Universitario, Via Orabona, 4, Bari 70125, Italy
| | - Götz Hensel
- Plant Reproductive Biology, Department of Physiology and Cell Biology, IPK, Corrensstraße 3, Seeland, Gatersleben D-06466, Germany
| | - Solmaz Khosravi
- Plant Reproductive Biology, Department of Physiology and Cell Biology, IPK, Corrensstraße 3, Seeland, Gatersleben D-06466, Germany
| | - Laura Maretto
- Department of Agronomy, Food, Natural Resources, Animal and Environment, University of Padova, Viale Università 16, Legnaro, Padova 35020, Italy
| | - Piergiorgio Stevanato
- Department of Agronomy, Food, Natural Resources, Animal and Environment, University of Padova, Viale Università 16, Legnaro, Padova 35020, Italy
| | - Fiorella Lo Schiavo
- Department of Biology, University of Padova, Via U. Bassi 58/b, Padova 35131, Italy
| | - Maria Concetta de Pinto
- Department of Biosciences, Biotechnology and Environment, University of Bari, Campus Universitario, Via Orabona, 4, Bari 70125, Italy
| | - Karin Krupinska
- Botanisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel D-24098, Germany
| | - Michela Zottini
- Department of Biology, University of Padova, Via U. Bassi 58/b, Padova 35131, Italy
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2
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Shu L, Li L, Jiang YQ, Yan J. Advances in membrane-tethered NAC transcription factors in plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 342:112034. [PMID: 38365003 DOI: 10.1016/j.plantsci.2024.112034] [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: 10/24/2023] [Revised: 02/08/2024] [Accepted: 02/11/2024] [Indexed: 02/18/2024]
Abstract
Transcription factors are central components in cell signal transduction networks and are critical regulators for gene expression. It is estimated that approximately 10% of all transcription factors are membrane-tethered. MTFs (membrane-bound transcription factors) are latent transcription factors that are inherently anchored in the cellular membrane in a dormant form. When plants encounter environmental stimuli, they will be released from the membrane by intramembrane proteases or by the ubiquitin proteasome pathway and then were translocated to the nucleus. The capacity to instantly activate dormant transcription factors is a critical strategy for modulating diverse cellular functions in response to external or internal signals, which provides an important transcriptional regulatory network in response to sudden stimulus and improves plant survival. NTLs (NTM1-like) are a small subset of NAC (NAM, ATAF1/2, CUC2) transcription factors, which contain a conserved NAC domain at the N-terminus and a transmembrane domain at the C-terminus. In the past two decades, several NTLs have been identified from several species, and most of them are involved in both development and stress response. In this review, we review the reports and findings on NTLs in plants and highlight the mechanism of their nuclear import as well as their functions in regulating plant growth and stress response.
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Affiliation(s)
- Lin Shu
- College of Plant Protection, Henan Agricultural University, Zhengzhou, Henan province 450002, China
| | - Longhui Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, Henan province 450002, China
| | - Yuan-Qing Jiang
- State Key Laboratory of Crop Stress Biology for Arid Areas and, College of Life Sciences, Northwest A & F University, Yangling, Shaanxi province 712100, China
| | - Jingli Yan
- College of Plant Protection, Henan Agricultural University, Zhengzhou, Henan province 450002, China.
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3
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Canal MV, Mansilla N, Gras DE, Ibarra A, Figueroa CM, Gonzalez DH, Welchen E. Cytochrome c levels affect the TOR pathway to regulate growth and metabolism under energy-deficient conditions. THE NEW PHYTOLOGIST 2024; 241:2039-2058. [PMID: 38191763 DOI: 10.1111/nph.19506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/03/2023] [Indexed: 01/10/2024]
Abstract
Mitochondrial function is essential for plant growth, but the mechanisms involved in adjusting growth and metabolism to changes in mitochondrial energy production are not fully understood. We studied plants with reduced expression of CYTC-1, one of two genes encoding the respiratory chain component cytochrome c (CYTc) in Arabidopsis, to understand how mitochondria communicate their status to coordinate metabolism and growth. Plants with CYTc deficiency show decreased mitochondrial membrane potential and lower ATP content, even when carbon sources are present. They also exhibit higher free amino acid content, induced autophagy, and increased resistance to nutritional stress caused by prolonged darkness, similar to plants with triggered starvation signals. CYTc deficiency affects target of rapamycin (TOR)-pathway activation, reducing S6 kinase (S6K) and RPS6A phosphorylation, as well as total S6K protein levels due to increased protein degradation via proteasome and autophagy. TOR overexpression restores growth and other parameters affected in cytc-1 mutants, even if mitochondrial membrane potential and ATP levels remain low. We propose that CYTc-deficient plants coordinate their metabolism and energy availability by reducing TOR-pathway activation as a preventive signal to adjust growth in anticipation of energy exhaustion, thus providing a mechanism by which changes in mitochondrial activity are transduced to the rest of the cell.
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Affiliation(s)
- María Victoria Canal
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Natanael Mansilla
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Diana E Gras
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Agustín Ibarra
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Carlos M Figueroa
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Daniel H Gonzalez
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Elina Welchen
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
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4
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Bychkov IA, Pojidaeva ES, Doroshenko AS, Khripach VA, Kudryakova NV, Kusnetsov VV. Phytohormones as Regulators of Mitochondrial Gene Expression in Arabidopsis thaliana. Int J Mol Sci 2023; 24:16924. [PMID: 38069246 PMCID: PMC10707152 DOI: 10.3390/ijms242316924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
The coordination of activities between nuclei and organelles in plant cells involves information exchange, in which phytohormones may play essential roles. Therefore, the dissection of the mechanisms of hormone-related integration between phytohormones and mitochondria is an important and challenging task. Here, we found that inputs from multiple hormones may cause changes in the transcript accumulation of mitochondrial-encoded genes and nuclear genes encoding mitochondrial (mt) proteins. In particular, treatments with exogenous hormones induced changes in the GUS expression in the reporter line possessing a 5'-deletion fragment of the RPOTmp promoter. These changes corresponded in part to the up- or downregulation of RPOTmp in wild-type plants, which affects the transcription of mt-encoded genes, implying that the promoter fragment of the RPOTmp gene is functionally involved in the responses to IAA (indole-3-acetic acid), ACC (1-aminocyclopropane-1-carboxylic acid), and ABA (abscisic acid). Hormone-dependent modulations in the expression of mt-encoded genes can also be mediated through mitochondrial transcription termination factors 15, 17, and 18 of the mTERF family and genes for tetratricopeptide repeat proteins that are coexpressed with mTERF genes, in addition to SWIB5 encoding a mitochondrial SWI/SNF (nucleosome remodeling) complex B protein. These genes specifically respond to hormone treatment, displaying both negative and positive regulation in a context-dependent manner. According to bioinformatic resources, their promoter region possesses putative cis-acting elements involved in responses to phytohormones. Alternatively, the hormone-related transcriptional activity of these genes may be modulated indirectly, which is especially relevant for brassinosteroids (BS). In general, the results of this study indicate that hormones are essential mediators that are able to cause alterations in the transcript accumulation of mt-related nuclear genes, which, in turn, trigger the expression of mt genes.
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Affiliation(s)
- Ivan A. Bychkov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; (I.A.B.); (E.S.P.); (A.S.D.)
| | - Elena S. Pojidaeva
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; (I.A.B.); (E.S.P.); (A.S.D.)
| | - Anastasia S. Doroshenko
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; (I.A.B.); (E.S.P.); (A.S.D.)
| | - Vladimir A. Khripach
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220072 Minsk, Belarus;
| | - Natalia V. Kudryakova
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; (I.A.B.); (E.S.P.); (A.S.D.)
| | - Victor V. Kusnetsov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; (I.A.B.); (E.S.P.); (A.S.D.)
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5
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Sajib SA, Kandel M, Prity SA, Oukacine C, Gakière B, Merendino L. Role of plastids and mitochondria in the early development of seedlings in dark growth conditions. FRONTIERS IN PLANT SCIENCE 2023; 14:1272822. [PMID: 37841629 PMCID: PMC10570830 DOI: 10.3389/fpls.2023.1272822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 09/12/2023] [Indexed: 10/17/2023]
Abstract
Establishment of the seedlings is a crucial stage of the plant life cycle. The success of this process is essential for the growth of the mature plant. In Nature, when seeds germinate under the soil, seedlings follow a dark-specific program called skotomorphogenesis, which is characterized by small, non-green cotyledons, long hypocotyl, and an apical hook-protecting meristematic cells. These developmental structures are required for the seedlings to emerge quickly and safely through the soil and gain autotrophy before the complete depletion of seed resources. Due to the lack of photosynthesis during this period, the seed nutrient stocks are the primary energy source for seedling development. The energy is provided by the bioenergetic organelles, mitochondria, and etioplast (plastid in the dark), to the cell in the form of ATP through mitochondrial respiration and etio-respiration processes, respectively. Recent studies suggest that the limitation of the plastidial or mitochondrial gene expression induces a drastic reprogramming of the seedling morphology in the dark. Here, we discuss the dark signaling mechanisms involved during a regular skotomorphogenesis and how the dysfunction of the bioenergetic organelles is perceived by the nucleus leading to developmental changes. We also describe the probable involvement of several plastid retrograde pathways and the interconnection between plastid and mitochondria during seedling development. Understanding the integration mechanisms of organellar signals in the developmental program of seedlings can be utilized in the future for better emergence of crops through the soil.
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Affiliation(s)
- Salek Ahmed Sajib
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
- Université Paris-Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
| | - Margot Kandel
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
- Université Paris-Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
| | - Sadia Akter Prity
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
- Université Paris-Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
| | - Cylia Oukacine
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
- Université Paris-Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
| | - Bertrand Gakière
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
- Université Paris-Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
| | - Livia Merendino
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
- Université Paris-Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Gif sur Yvette, France
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6
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Tran HC, Schmitt V, Lama S, Wang C, Launay-Avon A, Bernfur K, Sultan K, Khan K, Brunaud V, Liehrmann A, Castandet B, Levander F, Rasmusson AG, Mireau H, Delannoy E, Van Aken O. An mTRAN-mRNA interaction mediates mitochondrial translation initiation in plants. Science 2023; 381:eadg0995. [PMID: 37651534 DOI: 10.1126/science.adg0995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 08/02/2023] [Indexed: 09/02/2023]
Abstract
Plant mitochondria represent the largest group of respiring organelles on the planet. Plant mitochondrial messenger RNAs (mRNAs) lack Shine-Dalgarno-like ribosome-binding sites, so it is unknown how plant mitoribosomes recognize mRNA. We show that "mitochondrial translation factors" mTRAN1 and mTRAN2 are land plant-specific proteins, required for normal mitochondrial respiration chain biogenesis. Our studies suggest that mTRANs are noncanonical pentatricopeptide repeat (PPR)-like RNA binding proteins of the mitoribosomal "small" subunit. We identified conserved Adenosine (A)/Uridine (U)-rich motifs in the 5' regions of plant mitochondrial mRNAs. mTRAN1 binds this motif, suggesting that it is a mitoribosome homing factor to identify mRNAs. We demonstrate that mTRANs are likely required for translation of all plant mitochondrial mRNAs. Plant mitochondrial translation initiation thus appears to use a protein-mRNA interaction that is divergent from bacteria or mammalian mitochondria.
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Affiliation(s)
| | | | - Sbatie Lama
- Department of Biology, Lund University, Lund, Sweden
| | - Chuande Wang
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Alexandra Launay-Avon
- Université Paris-Saclay, CNRS, INRAE, Université d'Évry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France
- Université Paris Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Katja Bernfur
- Department of Chemistry, Lund University, Lund, Sweden
| | - Kristin Sultan
- Department of Immunotechnology, Lund University, Lund, Sweden
| | - Kasim Khan
- Department of Biology, Lund University, Lund, Sweden
| | - Véronique Brunaud
- Université Paris-Saclay, CNRS, INRAE, Université d'Évry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France
- Université Paris Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Arnaud Liehrmann
- Université Paris-Saclay, CNRS, INRAE, Université d'Évry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France
- Université Paris Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
- Université Paris-Saclay, CNRS, Université d'Évry, Laboratoire de Mathématiques et Modélisation d'Évry, 91037 Évry-Courcouronnes, France
| | - Benoît Castandet
- Université Paris-Saclay, CNRS, INRAE, Université d'Évry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France
- Université Paris Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Fredrik Levander
- Department of Immunotechnology, Lund University, Lund, Sweden
- National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Lund University, Lund, Sweden
| | | | - Hakim Mireau
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Etienne Delannoy
- Université Paris-Saclay, CNRS, INRAE, Université d'Évry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France
- Université Paris Cité, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
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7
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Iven V, Vanbuel I, Hendrix S, Cuypers A. The glutathione-dependent alarm triggers signalling responses involved in plant acclimation to cadmium. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:3300-3312. [PMID: 36882948 DOI: 10.1093/jxb/erad081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/28/2023] [Indexed: 06/08/2023]
Abstract
Cadmium (Cd) uptake from polluted soils inhibits plant growth and disturbs physiological processes, at least partly due to disturbances in the cellular redox environment. Although the sulfur-containing antioxidant glutathione is important in maintaining redox homeostasis, its role as an antioxidant can be overruled by its involvement in Cd chelation as a phytochelatin precursor. Following Cd exposure, plants rapidly invest in phytochelatin production, thereby disturbing the redox environment by transiently depleting glutathione concentrations. Consequently, a network of signalling responses is initiated, in which the phytohormone ethylene is an important player involved in the recovery of glutathione levels. Furthermore, these responses are intricately connected to organellar stress signalling and autophagy, and contribute to cell fate determination. In general, this may pave the way for acclimation (e.g. restoration of glutathione levels and organellar homeostasis) and plant tolerance in the case of mild stress conditions. This review addresses connections between these players and discusses the possible involvement of the gasotransmitter hydrogen sulfide in plant acclimation to Cd exposure.
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Affiliation(s)
- Verena Iven
- Environmental Biology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Isabeau Vanbuel
- Environmental Biology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Sophie Hendrix
- Environmental Biology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Ann Cuypers
- Environmental Biology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
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Kacprzak SM, Van Aken O. FRIENDLY is required for efficient dark-induced mitophagy and controlled senescence in Arabidopsis. Free Radic Biol Med 2023; 204:1-7. [PMID: 37085125 DOI: 10.1016/j.freeradbiomed.2023.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 03/17/2023] [Accepted: 04/11/2023] [Indexed: 04/23/2023]
Abstract
Mitochondria play essential roles in plant metabolism, supporting both development and stress responses. To maintain a healthy pool of mitochondria, several quality control systems are in place. Selected degradation of mitochondria by autophagy -mitophagy- has been extensively studied in yeast and animals, but information on mitophagy components in plants is limited. The 'Friendly Mitochondria' (FRIENDLY; FMT) protein, homologous to 'clustered mitochondria protein homolog' CLU in animals, was recently suggested to mediate mitophagy of depolarized mitochondria. In this study, we evaluated the role of FMT in carbon starvation- and dark senescence-induced mitophagy in Arabidopsis. Using mitophagy flux assays, we show that loss of FMT results in decreased mitophagy during dark-induced senescence. Mitophagy induced by inhibition of Target of Rapamycin (TOR) signalling is also partially impaired in fmt mutants. The FMT protein is mostly localised in the cytosol, but we show that during darkness FMT is redistributed into speckles, some of which associate with mitochondria. Fmt mutants were initially identified for their abnormal mitochondrial morphology, with mitochondria often forming clusters. We found that dark senescence strongly increases the number and size of mitochondrial clusters in fmt mutants. In agreement with a role for FMT in mitophagy, we show that fmt mutants show accelerated senescence phenotypes comparable to autophagy 11 (atg11) mutants, but less prominent than in atg5 mutants. Furthermore, FMT prevents excessive dark-induced cell death and hydrogen peroxide production, and supports mitophagy and greening in etiolated seedlings. Our findings thus indicate that FMT contributes to mitophagy and provide evidence that mitophagy is required for controlled senescence and prevention of accelerated cell death. We propose that FMT mediates efficient mitophagy by preventing mitochondrial clustering, thereby allowing mitochondria to be captured more effectively by autophagosomes, rather than by acting as a direct mitophagy receptor.
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9
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Kacprzak SM, Van Aken O. Carbon starvation, senescence and specific mitochondrial stresses, but not nitrogen starvation and general stresses, are major triggers for mitophagy in Arabidopsis. Autophagy 2022; 18:2894-2912. [PMID: 35311445 PMCID: PMC9673927 DOI: 10.1080/15548627.2022.2054039] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Selective degradation of mitochondria by autophagy (mitophagy) is thought to play an important role in mitochondrial quality control, but our understanding of which conditions induce mitophagy in plants is limited. Here, we developed novel reporter lines to monitor mitophagy in plants and surveyed the rate of mitophagy under a wide range of stresses and developmental conditions. Especially carbon starvation induced by dark-incubation causes a dramatic increase in mitophagy within a few hours, further increasing as dark-induced senescence progresses. Natural senescence was also a strong trigger of mitophagy, peaking when leaf yellowing became prominent. In contrast, nitrogen starvation, a trigger of general autophagy, does not induce strong increases in mitophagy. Similarly, general stresses such as hydrogen peroxide, heat, UV-B and hypoxia did not appear to trigger substantial mitophagy in plants. Additionally, we exposed plants to inhibitors of the mitochondrial electron transport chain, mitochondrial translation and protein import. Although short-term treatments did not induce high mitophagy rates, longer term exposures to uncoupling agent and inhibitors of mitochondrial protein import/translation could clearly increase mitophagic flux. These findings could further be confirmed using confocal microscopy. To validate that mitophagy is mediated by the autophagy pathway, we showed that mitophagic flux is abolished or strongly decreased in atg5/AuTophaGy 5 and atg11 mutants, respectively. Finally, we observed high rates of mitophagy in etiolated seedlings, which remarkably was completely repressed within 6 h after light exposure. In conclusion, we propose that dark-induced carbon starvation, natural senescence and specific mitochondrial stresses are key triggers of mitophagy in plants.Abbreviations: AA: antimycin A; ATG: AuToPhagy related; ConA: concanamycin A; DIS: dark-induced senescence; Dox: doxycycline; FCCP: carbonyl cyanide-p-trifluoromethoxyphenylhydrazone; GFP: green fluorescent protein; IDH1: isocitrate dehydrogenase 1; MB: MitoBlock-6; Mito-GFP: transgenic Arabidopsis line expressing a mitochondrially targeted protein fused to GFP; mtETC: mitochondrial electron transport chain; OXPHOS: oxidative phosphorylation; PQC: protein quality control; TOM20: Translocase of Outer Membrane 20.
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Affiliation(s)
| | - Olivier Van Aken
- Department of Biology, Lund University, Lund, Sweden,CONTACT Olivier Van Aken Molecular Cell Biology, Department of Biology, Lund, Sweden
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10
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He C, Liew LC, Yin L, Lewsey MG, Whelan J, Berkowitz O. The retrograde signaling regulator ANAC017 recruits the MKK9-MPK3/6, ethylene, and auxin signaling pathways to balance mitochondrial dysfunction with growth. THE PLANT CELL 2022; 34:3460-3481. [PMID: 35708648 PMCID: PMC9421482 DOI: 10.1093/plcell/koac177] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 05/29/2022] [Indexed: 05/12/2023]
Abstract
In plant cells, mitochondria are ideally positioned to sense and balance changes in energy metabolism in response to changing environmental conditions. Retrograde signaling from mitochondria to the nucleus is crucial for adjusting the required transcriptional responses. We show that ANAC017, the master regulator of mitochondrial stress, directly recruits a signaling cascade involving the plant hormones ethylene and auxin as well as the MAP KINASE KINASE (MKK) 9-MAP KINASE (MPK) 3/6 pathway in Arabidopsis thaliana. Chromatin immunoprecipitation followed by sequencing and overexpression demonstrated that ANAC017 directly regulates several genes of the ethylene and auxin pathways, including MKK9, 1-AMINO-CYCLOPROPANE-1-CARBOXYLATE SYNTHASE 2, and YUCCA 5, in addition to genes encoding transcription factors regulating plant growth and stress responses such as BASIC REGION/LEUCINE ZIPPER MOTIF (bZIP) 60, bZIP53, ANAC081/ATAF2, and RADICAL-INDUCED CELL DEATH1. A time-resolved RNA-seq experiment established that ethylene signaling precedes the stimulation of auxin signaling in the mitochondrial stress response, with a large part of the transcriptional regulation dependent on ETHYLENE-INSENSITIVE 3. These results were confirmed by mutant analyses. Our findings identify the molecular components controlled by ANAC017, which integrates the primary stress responses to mitochondrial dysfunction with whole plant growth via the activation of regulatory and partly antagonistic feedback loops.
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Affiliation(s)
- Cunman He
- Department of Animal, Plant and Soil Science, La Trobe University, Bundoora, Victoria 3086, Australia
- ARC Centre of Excellence in Plant Energy Biology, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Lim Chee Liew
- Department of Animal, Plant and Soil Science, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Lingling Yin
- Department of Animal, Plant and Soil Science, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Mathew G Lewsey
- Department of Animal, Plant and Soil Science, La Trobe University, Bundoora, Victoria 3086, Australia
| | - James Whelan
- Department of Animal, Plant and Soil Science, La Trobe University, Bundoora, Victoria 3086, Australia
- ARC Centre of Excellence in Plant Energy Biology, La Trobe University, Bundoora, Victoria 3086, Australia
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11
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Tao Y, Wan JX, Liu YS, Yang XZ, Shen RF, Zhu XF. The NAC transcription factor ANAC017 regulates aluminum tolerance by regulating the cell wall-modifying genes. PLANT PHYSIOLOGY 2022; 189:2517-2534. [PMID: 35512200 PMCID: PMC9342997 DOI: 10.1093/plphys/kiac197] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/28/2022] [Indexed: 05/06/2023]
Abstract
Aluminum (Al) toxicity is one of the key factors limiting crop production in acid soils; however, little is known about its transcriptional regulation in plants. In this study, we characterized the role of a NAM, ATAF1/2, and cup-shaped cotyledon 2 (NAC) transcription factors (TFs), ANAC017, in the regulation of Al tolerance in Arabidopsis (Arabidopsis thaliana). ANAC017 was localized in the nucleus and exhibited constitutive expression in the root, stem, leaf, flower, and silique, although its expression and protein accumulation were repressed by Al stress. Loss of function of ANAC017 enhanced Al tolerance when compared with wild-type Col-0 and was accompanied by lower root and root cell wall Al content. Furthermore, both hemicellulose and xyloglucan content decreased in the anac017 mutants, indicating the possible interaction between ANAC017 and xyloglucan endotransglucosylase/hydrolase (XTH). Interestingly, the expression of XTH31, which is responsible for xyloglucan modification, was downregulated in the anac017 mutants regardless of Al supply, supporting the possible interaction between ANAC017 and XTH31. Yeast one-hybrid, dual-luciferase reporter assay, and chromatin immunoprecipitation-quantitative PCR analysis revealed that ANAC017 positively regulated the expression of XTH31 through directly binding to the XTH31 promoter region, and overexpression of XTH31 in the anac017 mutant background rescued its Al-tolerance phenotype. In conclusion, we identified that the tTF ANAC017 acts upstream of XTH31 to regulate Al tolerance in Arabidopsis.
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Affiliation(s)
| | | | - Yu Song Liu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao Zheng Yang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ren Fang Shen
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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12
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De Backer J, Van Breusegem F, De Clercq I. Proteolytic Activation of Plant Membrane-Bound Transcription Factors. FRONTIERS IN PLANT SCIENCE 2022; 13:927746. [PMID: 35774815 PMCID: PMC9237531 DOI: 10.3389/fpls.2022.927746] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 05/23/2022] [Indexed: 06/03/2023]
Abstract
Due to the presence of a transmembrane domain, the subcellular mobility plan of membrane-bound or membrane-tethered transcription factors (MB-TFs) differs from that of their cytosolic counterparts. The MB-TFs are mostly locked in (sub)cellular membranes, until they are released by a proteolytic cleavage event or when the transmembrane domain (TMD) is omitted from the transcript due to alternative splicing. Here, we review the current knowledge on the proteolytic activation mechanisms of MB-TFs in plants, with a particular focus on regulated intramembrane proteolysis (RIP), and discuss the analogy with the proteolytic cleavage of MB-TFs in animal systems. We present a comprehensive inventory of all known and predicted MB-TFs in the model plant Arabidopsis thaliana and examine their experimentally determined or anticipated subcellular localizations and membrane topologies. We predict proteolytically activated MB-TFs by the mapping of protease recognition sequences and structural features that facilitate RIP in and around the TMD, based on data from metazoan intramembrane proteases. Finally, the MB-TF functions in plant responses to environmental stresses and in plant development are considered and novel functions for still uncharacterized MB-TFs are forecasted by means of a regulatory network-based approach.
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Affiliation(s)
- Jonas De Backer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB)-Center for Plant Systems Biology, Ghent, Belgium
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB)-Center for Plant Systems Biology, Ghent, Belgium
| | - Inge De Clercq
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB)-Center for Plant Systems Biology, Ghent, Belgium
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13
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Zhang Y, Lu Y, El Sayyed H, Bian J, Lin J, Li X. Transcription factor dynamics in plants: Insights and technologies for in vivo imaging. PLANT PHYSIOLOGY 2022; 189:23-36. [PMID: 35134239 PMCID: PMC9070795 DOI: 10.1093/plphys/kiac042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
Biochemical and genetic approaches have been extensively used to study transcription factor (TF) functions, but their dynamic behaviors and the complex ways in which they regulate transcription in plant cells remain unexplored, particularly behaviors such as translocation and binding to DNA. Recent developments in labeling and imaging techniques provide the necessary sensitivity and resolution to study these behaviors in living cells. In this review, we present an up-to-date portrait of the dynamics and regulation of TFs under physiologically relevant conditions and then summarize recent advances in fluorescent labeling strategies and imaging techniques. We then discuss future prospects and challenges associated with the application of these techniques to examine TFs' intricate dance in living plants.
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Affiliation(s)
- Yuan Zhang
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Yuqing Lu
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Hafez El Sayyed
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Jiahui Bian
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Jinxing Lin
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
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14
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Møller IM, Rasmusson AG, Van Aken O. Plant mitochondria - past, present and future. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:912-959. [PMID: 34528296 DOI: 10.1111/tpj.15495] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
The study of plant mitochondria started in earnest around 1950 with the first isolations of mitochondria from animal and plant tissues. The first 35 years were spent establishing the basic properties of plant mitochondria and plant respiration using biochemical and physiological approaches. A number of unique properties (compared to mammalian mitochondria) were observed: (i) the ability to oxidize malate, glycine and cytosolic NAD(P)H at high rates; (ii) the partial insensitivity to rotenone, which turned out to be due to the presence of a second NADH dehydrogenase on the inner surface of the inner mitochondrial membrane in addition to the classical Complex I NADH dehydrogenase; and (iii) the partial insensitivity to cyanide, which turned out to be due to an alternative oxidase, which is also located on the inner surface of the inner mitochondrial membrane, in addition to the classical Complex IV, cytochrome oxidase. With the appearance of molecular biology methods around 1985, followed by genomics, further unique properties were discovered: (iv) plant mitochondrial DNA (mtDNA) is 10-600 times larger than the mammalian mtDNA, yet it only contains approximately 50% more genes; (v) plant mtDNA has kept the standard genetic code, and it has a low divergence rate with respect to point mutations, but a high recombinatorial activity; (vi) mitochondrial mRNA maturation includes a uniquely complex set of activities for processing, splicing and editing (at hundreds of sites); (vii) recombination in mtDNA creates novel reading frames that can produce male sterility; and (viii) plant mitochondria have a large proteome with 2000-3000 different proteins containing many unique proteins such as 200-300 pentatricopeptide repeat proteins. We describe the present and fairly detailed picture of the structure and function of plant mitochondria and how the unique properties make their metabolism more flexible allowing them to be involved in many diverse processes in the plant cell, such as photosynthesis, photorespiration, CAM and C4 metabolism, heat production, temperature control, stress resistance mechanisms, programmed cell death and genomic evolution. However, it is still a challenge to understand how the regulation of metabolism and mtDNA expression works at the cellular level and how retrograde signaling from the mitochondria coordinates all those processes.
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Affiliation(s)
- Ian Max Møller
- Department of Molecular Biology and Genetics, Aarhus University, Forsøgsvej 1, DK-4200, Slagelse, Denmark
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15
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Welchen E, Gonzalez DH. Breaking boundaries: exploring short- and long-distance mitochondrial signalling in plants. THE NEW PHYTOLOGIST 2021; 232:494-501. [PMID: 34255867 DOI: 10.1111/nph.17614] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/29/2021] [Indexed: 05/20/2023]
Abstract
Communication of mitochondria with other cell compartments is essential for the coordination of cellular functions. Mitochondria send retrograde signals through metabolites, redox changes, direct organelle contacts and protein trafficking. Accumulating evidence indicates that, in animal systems, changes in mitochondrial function also trigger responses in other, either neighbouring or distantly located, cells. Although not clearly established, there are indications that this type of communication may also be operative in plants. Grafting experiments suggested that the translocation of entire mitochondria or submitochondrial vesicles between neighbouring cells is possible in plants, as already documented in animals. Changes in mitochondrial function also regulate cell-to-cell communication via plasmodesmata and may be transmitted over long distances through plant hormones acting as mitokines to relay mitochondrial signals to distant tissues. Long-distance movement of transcripts encoding mitochondrial proteins involved in crucial aspects of metabolism and retrograde signalling was also described. Finally, changes in mitochondrial reactive species (ROS) production may affect the 'ROS wave' that triggers systemic acquired acclimation throughout the plant. In this review, we summarise available evidence suggesting that mitochondria establish sophisticated communications not only within the cell but also with neighbouring cells and distant tissues to coordinate plant growth and stress responses in a cell nonautonomous manner.
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Affiliation(s)
- Elina Welchen
- Facultad de Bioquímica y Ciencias Biológicas, Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Universidad Nacional del Litoral, Santa Fe, 3000, Argentina
| | - Daniel H Gonzalez
- Facultad de Bioquímica y Ciencias Biológicas, Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Universidad Nacional del Litoral, Santa Fe, 3000, Argentina
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16
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Oxidative signalling in seed germination and early seedling growth: an emerging role for ROS trafficking and inter-organelle communication. Biochem J 2021; 478:1977-1984. [PMID: 34047788 DOI: 10.1042/bcj20200934] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/09/2021] [Accepted: 05/11/2021] [Indexed: 12/17/2022]
Abstract
Underground early development of higher plants includes two distinct developmental processes, seed germination and then skotomorphogenesis, a mechanism which favours elongation of the hypocotyl and helps the seedling to find light. Interestingly, both processes, which are regulated by plant hormones, have been shown to depend on reactive oxygen species metabolism and to be related to mitochondrial retrograde signalling. Here we review the recent outcomes in this field of research and highlight the emerging role of ROS communication between organelles and cell compartments. We point out the role of mitochondria as an environmental and developmental sensor organelle that regulates ROS homeostasis and downstream events and we propose future directions of research that should help better understanding the roles of ROS in germination and seedling emergence.
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17
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Van Aken O. Mitochondrial redox systems as central hubs in plant metabolism and signaling. PLANT PHYSIOLOGY 2021; 186:36-52. [PMID: 33624829 PMCID: PMC8154082 DOI: 10.1093/plphys/kiab101] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 02/11/2021] [Indexed: 05/06/2023]
Abstract
Plant mitochondria are indispensable for plant metabolism and are tightly integrated into cellular homeostasis. This review provides an update on the latest research concerning the organization and operation of plant mitochondrial redox systems, and how they affect cellular metabolism and signaling, plant development, and stress responses. New insights into the organization and operation of mitochondrial energy systems such as the tricarboxylic acid cycle and mitochondrial electron transport chain (mtETC) are discussed. The mtETC produces reactive oxygen and nitrogen species, which can act as signals or lead to cellular damage, and are thus efficiently removed by mitochondrial antioxidant systems, including Mn-superoxide dismutase, ascorbate-glutathione cycle, and thioredoxin-dependent peroxidases. Plant mitochondria are tightly connected with photosynthesis, photorespiration, and cytosolic metabolism, thereby providing redox-balancing. Mitochondrial proteins are targets of extensive post-translational modifications, but their functional significance and how they are added or removed remains unclear. To operate in sync with the whole cell, mitochondria can communicate their functional status via mitochondrial retrograde signaling to change nuclear gene expression, and several recent breakthroughs here are discussed. At a whole organism level, plant mitochondria thus play crucial roles from the first minutes after seed imbibition, supporting meristem activity, growth, and fertility, until senescence of darkened and aged tissue. Finally, plant mitochondria are tightly integrated with cellular and organismal responses to environmental challenges such as drought, salinity, heat, and submergence, but also threats posed by pathogens. Both the major recent advances and outstanding questions are reviewed, which may help future research efforts on plant mitochondria.
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Affiliation(s)
- Olivier Van Aken
- Department of Biology, Lund University, Lund, Sweden
- Author for communication:
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18
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Welchen E, Canal MV, Gras DE, Gonzalez DH. Cross-talk between mitochondrial function, growth, and stress signalling pathways in plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4102-4118. [PMID: 33369668 DOI: 10.1093/jxb/eraa608] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/22/2020] [Indexed: 05/16/2023]
Abstract
Plant mitochondria harbour complex metabolic routes that are interconnected with those of other cell compartments, and changes in mitochondrial function remotely influence processes in different parts of the cell. This implies the existence of signals that convey information about mitochondrial function to the rest of the cell. Increasing evidence indicates that metabolic and redox signals are important for this process, but changes in ion fluxes, protein relocalization, and physical contacts with other organelles are probably also involved. Besides possible direct effects of these signalling molecules on cellular functions, changes in mitochondrial physiology also affect the activity of different signalling pathways that modulate plant growth and stress responses. As a consequence, mitochondria influence the responses to internal and external factors that modify the activity of these pathways and associated biological processes. Acting through the activity of hormonal signalling pathways, mitochondria may also exert remote control over distant organs or plant tissues. In addition, an intimate cross-talk of mitochondria with energy signalling pathways, such as those represented by TARGET OF RAPAMYCIN and SUCROSE NON-FERMENTING1-RELATED PROTEIN KINASE 1, can be envisaged. This review discusses available evidence on the role of mitochondria in shaping plant growth and stress responses through various signalling pathways.
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Affiliation(s)
- Elina Welchen
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
| | - María Victoria Canal
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
| | - Diana E Gras
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
| | - Daniel H Gonzalez
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
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19
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Depaepe T, Hendrix S, Janse van Rensburg HC, Van den Ende W, Cuypers A, Van Der Straeten D. At the Crossroads of Survival and Death: The Reactive Oxygen Species-Ethylene-Sugar Triad and the Unfolded Protein Response. TRENDS IN PLANT SCIENCE 2021; 26:338-351. [PMID: 33431325 DOI: 10.1016/j.tplants.2020.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/09/2020] [Accepted: 12/14/2020] [Indexed: 05/13/2023]
Abstract
Upon stress, a trade-off between plant growth and defense responses defines the capacity for survival. Stress can result in accumulation of misfolded proteins in the endoplasmic reticulum (ER) and other organelles. To cope with these proteotoxic effects, plants rely on the unfolded protein response (UPR). The involvement of reactive oxygen species (ROS), ethylene (ETH), and sugars, as well as their crosstalk, in general stress responses is well established, yet their role in UPR deserves further scrutiny. Here, a synopsis of current evidence for ROS-ETH-sugar crosstalk in UPR is discussed. We propose that this triad acts as a major signaling hub at the crossroads of survival and death, integrating information from ER, chloroplasts, and mitochondria, thereby facilitating a coordinated stress response.
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Affiliation(s)
- Thomas Depaepe
- Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Sophie Hendrix
- Environmental Biology, Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium
| | - Henry C Janse van Rensburg
- Laboratory of Molecular Plant Biology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001, Leuven, Belgium
| | - Wim Van den Ende
- Laboratory of Molecular Plant Biology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001, Leuven, Belgium
| | - Ann Cuypers
- Environmental Biology, Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium.
| | - Dominique Van Der Straeten
- Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium.
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20
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Jurdak R, Launay-Avon A, Paysant-Le Roux C, Bailly C. Retrograde signalling from the mitochondria to the nucleus translates the positive effect of ethylene on dormancy breaking of Arabidopsis thaliana seeds. THE NEW PHYTOLOGIST 2021; 229:2192-2205. [PMID: 33020928 DOI: 10.1111/nph.16985] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/21/2020] [Indexed: 05/22/2023]
Abstract
Ethylene and reactive oxygen species (ROS) regulate seed dormancy alleviation, but the molecular basis of their action and crosstalk remains largely unknown. Here we studied the mechanism of Arabidopsis seed dormancy release by ethylene using cell imaging, and genetic and transcriptomics approaches, in order to tackle its possible interaction with ROS homeostasis. We found that the effect of ethylene on seed germination required ROS production by the mitochondrial electron transport chain. Seed response to ethylene involved a mitochondrial retrograde response (MRR) through nuclear ROS production and upregulation of the MRR components AOX1a and ANAC013, but also required the activation of the ethylene canonical pathway. Together our data allowed deciphering of the mode of action of ethylene on seed germination and the associated dynamics of ROS production. Our findings highlight the occurrence of retrograde signalling in seed germination.
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Affiliation(s)
- Rana Jurdak
- IBPS, CNRS, UMR 7622 Biologie du Développement, Sorbonne Université, Paris, F-75005, France
- Biodiversity and Functional Genomics Laboratory, Université Saint-Joseph de Beyrouth, Beyrouth, 1107 2050, Lebanon
| | - Alexandra Launay-Avon
- CNRS, INRAE, Université d'Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, Orsay, 91405, France
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, Orsay, 91405, France
| | - Christine Paysant-Le Roux
- CNRS, INRAE, Université d'Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, Orsay, 91405, France
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, Orsay, 91405, France
| | - Christophe Bailly
- IBPS, CNRS, UMR 7622 Biologie du Développement, Sorbonne Université, Paris, F-75005, France
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21
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Tran HC, Van Aken O. Mitochondrial unfolded protein-related responses across kingdoms: similar problems, different regulators. Mitochondrion 2020; 53:166-177. [PMID: 32502630 DOI: 10.1016/j.mito.2020.05.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/19/2020] [Accepted: 05/22/2020] [Indexed: 02/06/2023]
Abstract
Mitochondria are key components of eukaryotic cells, so their proper functioning is monitored via different mitochondrial signalling responses. One of these mitochondria-to-nuclear 'retrograde' responses to maintain mitochondrial homeostasis is the mitochondrial unfolded protein response (UPRmt), which can be activated by a variety of defects including blocking mitochondrial translation, respiration, protein import or transmembrane potential. Although UPRmt was first reported in cultured mammalian cells, this signalling pathway has also been extensively studied in the nematode Caenorhabditis elegans. In yeast, there are no published studies focusing on UPRmt in a strict sense, but other unfolded protein responses (UPR) that appear related to UPRmt have been described, such as the UPR activated by protein mistargeting (UPRam) and mitochondrial compromised protein import response (mitoCPR). In plants, very little is known about UPRmt and only recently some of the regulators have been identified. In this paper, we summarise and compare the current knowledge of the UPRmt and related responses across eukaryotic kingdoms: animals, fungi and plants. Our comparison suggests that each kingdom has evolved its own specific set of regulators, however, the functional categories represented among UPRmt-related target genes appear to be largely overlapping. This indicates that the strategies for preserving proper mitochondrial functions are partially conserved, targeting mitochondrial chaperones, proteases, import components, dynamics and stress response, but likely also non-mitochondrial functions including growth regulators/hormone balance and amino acid metabolism. We also identify homologs of known UPRmt regulators and responsive genes across kingdoms, which may be interesting targets for future research.
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22
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Pfannschmidt T, Terry MJ, Van Aken O, Quiros PM. Retrograde signals from endosymbiotic organelles: a common control principle in eukaryotic cells. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190396. [PMID: 32362267 DOI: 10.1098/rstb.2019.0396] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Endosymbiotic organelles of eukaryotic cells, the plastids, including chloroplasts and mitochondria, are highly integrated into cellular signalling networks. In both heterotrophic and autotrophic organisms, plastids and/or mitochondria require extensive organelle-to-nucleus communication in order to establish a coordinated expression of their own genomes with the nuclear genome, which encodes the majority of the components of these organelles. This goal is achieved by the use of a variety of signals that inform the cell nucleus about the number and developmental status of the organelles and their reaction to changing external environments. Such signals have been identified in both photosynthetic and non-photosynthetic eukaryotes (known as retrograde signalling and retrograde response, respectively) and, therefore, appear to be universal mechanisms acting in eukaryotes of all kingdoms. In particular, chloroplasts and mitochondria both harbour crucial redox reactions that are the basis of eukaryotic life and are, therefore, especially susceptible to stress from the environment, which they signal to the rest of the cell. These signals are crucial for cell survival, lifespan and environmental adjustment, and regulate quality control and targeted degradation of dysfunctional organelles, metabolic adjustments, and developmental signalling, as well as induction of apoptosis. The functional similarities between retrograde signalling pathways in autotrophic and non-autotrophic organisms are striking, suggesting the existence of common principles in signalling mechanisms or similarities in their evolution. Here, we provide a survey for the newcomers to this field of research and discuss the importance of retrograde signalling in the context of eukaryotic evolution. Furthermore, we discuss commonalities and differences in retrograde signalling mechanisms and propose retrograde signalling as a general signalling mechanism in eukaryotic cells that will be also of interest for the specialist. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.
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Affiliation(s)
- Thomas Pfannschmidt
- Institute of Botany, Plant Physiology, Leibniz University Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany
| | - Matthew J Terry
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Olivier Van Aken
- Department of Biology, Lund University, Sölvegatan 35, 223 62 Lund, Sweden
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