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D’Alessandro S, Velay F, Lebrun R, Zafirov D, Mehrez M, Romand S, Saadouni R, Forzani C, Citerne S, Montané MH, Robaglia C, Menand B, Meyer C, Field B. Posttranslational regulation of photosynthetic activity via the TOR kinase in plants. SCIENCE ADVANCES 2024; 10:eadj3268. [PMID: 38896607 PMCID: PMC11186500 DOI: 10.1126/sciadv.adj3268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 05/13/2024] [Indexed: 06/21/2024]
Abstract
Chloroplasts are the powerhouse of the plant cell, and their activity must be matched to plant growth to avoid photooxidative damage. We have identified a posttranslational mechanism linking the eukaryotic target of rapamycin (TOR) kinase that promotes growth and the guanosine tetraphosphate (ppGpp) signaling pathway of prokaryotic origins that regulates chloroplast activity and photosynthesis in particular. We find that RelA SpoT homolog 3 (RSH3), a nuclear-encoded enzyme responsible for ppGpp biosynthesis, interacts directly with the TOR complex via a plant-specific amino-terminal region which is phosphorylated in a TOR-dependent manner. Down-regulating TOR activity causes a rapid increase in ppGpp synthesis in RSH3 overexpressors and reduces photosynthetic capacity in an RSH-dependent manner in wild-type plants. The TOR-RSH3 signaling axis therefore regulates the equilibrium between chloroplast activity and plant growth, setting a precedent for the regulation of organellar function by TOR.
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Affiliation(s)
- Stefano D’Alessandro
- Aix Marseille Univ, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France
- Università di Torino, Dipartimento di Scienze della vita e Biologia dei Sistemi, 10135 Torino, Italy
| | - Florent Velay
- Aix Marseille Univ, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France
| | - Régine Lebrun
- Aix Marseille Univ, CNRS, Plate-forme Protéomique, Marseille Protéomique (MaP), IMM FR 3479, 31 Chemin Joseph Aiguier, 13009 Marseille, France
| | - Delyan Zafirov
- Aix Marseille Univ, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France
| | - Marwa Mehrez
- Aix Marseille Univ, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France
- Faculty of Sciences of Tunis, University of Tunis El Manar, 2092 Tunis, Tunisia
| | - Shanna Romand
- Aix Marseille Univ, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France
| | - Rim Saadouni
- Aix Marseille Univ, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France
- Aix Marseille Univ, CNRS, Plate-forme Protéomique, Marseille Protéomique (MaP), IMM FR 3479, 31 Chemin Joseph Aiguier, 13009 Marseille, France
| | - Céline Forzani
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Sylvie Citerne
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | | | | | - Benoît Menand
- Aix Marseille Univ, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France
| | - Christian Meyer
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Ben Field
- Aix Marseille Univ, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France
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2
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Foresi N, De Marco MA, Del Castello F, Ramirez L, Nejamkin A, Calo G, Grimsley N, Correa-Aragunde N, Martínez-Noël GMA. The tiny giant of the sea, Ostreococcus's unique adaptations. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 211:108661. [PMID: 38735153 DOI: 10.1016/j.plaphy.2024.108661] [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: 12/17/2023] [Revised: 04/14/2024] [Accepted: 04/23/2024] [Indexed: 05/14/2024]
Abstract
Ostreococcus spp. are unicellular organisms with one of the simplest cellular organizations. The sequencing of the genomes of different Ostreococcus species has reinforced this status since Ostreococcus tauri has one most compact nuclear genomes among eukaryotic organisms. Despite this, it has retained a number of genes, setting it apart from other organisms with similar small genomes. Ostreococcus spp. feature a substantial number of selenocysteine-containing proteins, which, due to their higher catalytic activity compared to their selenium-lacking counterparts, may require a reduced quantity of proteins. Notably, O. tauri encodes several ammonium transporter genes, that may provide it with a competitive edge for acquiring nitrogen (N). This characteristic makes it an intriguing model for studying the efficient use of N in eukaryotes. Under conditions of low N availability, O. tauri utilizes N from abundant proteins or amino acids, such as L-arginine, similar to higher plants. However, the presence of a nitric oxide synthase (L-arg substrate) sheds light on a new metabolic pathway for L-arg in algae. The metabolic adaptations of O. tauri to day and night cycles offer valuable insights into carbon and iron metabolic configuration. O. tauri has evolved novel strategies to optimize iron uptake, lacking the classic components of the iron absorption mechanism. Overall, the cellular and genetic characteristics of Ostreococcus contribute to its evolutionary success, making it an excellent model for studying the physiological and genetic aspects of how green algae have adapted to the marine environment. Furthermore, given its potential for lipid accumulation and its marine habitat, it may represent a promising avenue for third-generation biofuels.
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Affiliation(s)
- Noelia Foresi
- Instituto de Investigaciones Biológicas-UNMdP-CONICET, Mar del Plata, Argentina.
| | - María Agustina De Marco
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC)-CONICET-FIBA, Mar del Plata, Argentina
| | | | - Leonor Ramirez
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, SE-901 87, Umeå, Sweden
| | - Andres Nejamkin
- Instituto de Investigaciones Biológicas-UNMdP-CONICET, Mar del Plata, Argentina
| | - Gonzalo Calo
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC)-CONICET-FIBA, Mar del Plata, Argentina
| | - Nigel Grimsley
- CNRS, LBBM, Sorbonne Université OOB, 1 Avenue de Pierre Fabre, 66650, Banyuls-sur-Mer, France
| | | | - Giselle M A Martínez-Noël
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC)-CONICET-FIBA, Mar del Plata, Argentina.
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3
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Perdoux R, Barrada A, Boulaiz M, Garau C, Belbachir C, Lecampion C, Montané MH, Menand B. A drug-resistant mutation in plant target of rapamycin validates the specificity of ATP-competitive TOR inhibitors in vivo. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:1344-1355. [PMID: 38011587 DOI: 10.1111/tpj.16564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/27/2023] [Accepted: 11/13/2023] [Indexed: 11/29/2023]
Abstract
Kinases are major components of cellular signaling pathways, regulating key cellular activities through phosphorylation. Kinase inhibitors are efficient tools for studying kinase targets and functions, however assessing their kinase specificity in vivo is essential. The identification of resistant kinase mutants has been proposed to be the most convincing approach to achieve this goal. Here, we address this issue in plants via a pharmacogenetic screen for mutants resistant to the ATP-competitive TOR inhibitor AZD-8055. The eukaryotic TOR (Target of Rapamycin) kinase is emerging as a major hub controlling growth responses in plants largely thanks to the use of ATP-competitive inhibitors. We identified a dominant mutation in the DFG motif of the Arabidopsis TOR kinase domain that leads to very strong resistance to AZD-8055. This resistance was characterized by measuring root growth, photosystem II (PSII) activity in leaves and phosphorylation of YAK1 (Yet Another Kinase 1) and RPS6 (Ribosomal protein S6), a direct and an indirect target of TOR respectively. Using other ATP-competitive TOR inhibitors, we also show that the dominant mutation is particularly efficient for resistance to drugs structurally related to AZD-8055. Altogether, this proof-of-concept study demonstrates that a pharmacogenetic screen in Arabidopsis can be used to successfully identify the target of a kinase inhibitor in vivo and therefore to demonstrate inhibitor specificity. Thanks to the conservation of kinase families in eukaryotes, and the possibility of creating amino acid substitutions by genome editing, this work has great potential for extending studies on the evolution of signaling pathways in eukaryotes.
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Affiliation(s)
- Romain Perdoux
- Aix-Marseille Univ, CEA, CNRS, BIAM, LGBP Team, Marseille, France
| | - Adam Barrada
- Aix-Marseille Univ, CEA, CNRS, BIAM, LGBP Team, Marseille, France
| | - Manal Boulaiz
- Aix-Marseille Univ, CEA, CNRS, BIAM, LGBP Team, Marseille, France
| | - Camille Garau
- Aix-Marseille Univ, CEA, CNRS, BIAM, LGBP Team, Marseille, France
| | | | - Cécile Lecampion
- Aix-Marseille Univ, CEA, CNRS, BIAM, LGBP Team, Marseille, France
| | | | - Benoît Menand
- Aix-Marseille Univ, CEA, CNRS, BIAM, LGBP Team, Marseille, France
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4
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Mallén-Ponce MJ, Pérez-Pérez ME, Crespo JL. Deciphering the function and evolution of the target of rapamycin signaling pathway in microalgae. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:6993-7005. [PMID: 35710309 PMCID: PMC9664231 DOI: 10.1093/jxb/erac264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
Microalgae constitute a highly diverse group of photosynthetic microorganisms that are widely distributed on Earth. The rich diversity of microalgae arose from endosymbiotic events that took place early in the evolution of eukaryotes and gave rise to multiple lineages including green algae, the ancestors of land plants. In addition to their fundamental role as the primary source of marine and freshwater food chains, microalgae are essential producers of oxygen on the planet and a major biotechnological target for sustainable biofuel production and CO2 mitigation. Microalgae integrate light and nutrient signals to regulate cell growth. Recent studies identified the target of rapamycin (TOR) kinase as a central regulator of cell growth and a nutrient sensor in microalgae. TOR promotes protein synthesis and regulates processes that are induced under nutrient stress such as autophagy and the accumulation of triacylglycerol and starch. A detailed analysis of representative genomes from the entire microalgal lineage revealed that the highly conserved central components of the TOR pathway are likely to have been present in the last eukaryotic common ancestor, and the loss of specific TOR signaling elements at an early stage in the evolution of microalgae. Here we examine the evolutionary conservation of TOR signaling components in diverse microalgae and discuss recent progress of this signaling pathway in these organisms.
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Affiliation(s)
- Manuel J Mallén-Ponce
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Sevilla, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Sevilla, Spain
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5
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Li L, Zhu T, Huang L, Ren M. Target of Rapamycin Signaling Involved in the Regulation of Photosynthesis and Cellular Metabolism in Chlorella sorokiniana. Int J Mol Sci 2022; 23:ijms23137451. [PMID: 35806454 PMCID: PMC9266951 DOI: 10.3390/ijms23137451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 06/24/2022] [Accepted: 06/28/2022] [Indexed: 11/16/2022] Open
Abstract
Target of rapamycin (TOR) is a serine/threonine protein kinase that plays a central regulating role in cell proliferation, growth, and metabolism, but little is known about the TOR signaling pathway in Chlorella sorokiniana. In this study, a Chlorella sorokiniana DP-1 strain was isolated and identified, and its nutritional compositions were analyzed. Based on homologous sequence analysis, the conserved CsTOR protein was found in the genome of Chlorella sorokiniana. In addition, the key components of TOR complex 1 (TORC1) were present, but the components of TORC2 (RICTOR and SIN1) were absent in Chlorella sorokiniana. Pharmacological assays showed that Chlorella sorokiniana DP-1 was insensitive to rapamycin, Torin1 and KU0063794, whereas AZD8055 could significantly inhibit the growth of Chlorella sorokiniana. RNA-seq analysis showed that CsTOR regulated various metabolic processes and signal transduction pathways in AZD8055-treated Chlorella sorokiniana DP-1. Most genes involved in photosynthesis and carbon fixation in Chlorella sorokiniana DP-1 were significantly downregulated under CsTOR inhibition, indicating that CsTOR positively regulated the photosynthesis in Chlorella sorokiniana. Furthermore, CsTOR controlled protein synthesis and degradation by positively regulating ribosome synthesis and negatively regulating autophagy. These observations suggested that CsTOR plays an important role in photosynthesis and cellular metabolism, and provide new insights into the function of CsTOR in Chlorella sorokiniana.
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6
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A biophotoelectrode based on boronic acid-modified Chlorella vulgaris cells integrated within a redox polymer. Bioelectrochemistry 2022; 146:108128. [DOI: 10.1016/j.bioelechem.2022.108128] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/22/2022] [Accepted: 03/29/2022] [Indexed: 12/31/2022]
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7
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Artins A, Caldana C. The metabolic homeostaTOR: The balance of holding on or letting grow. CURRENT OPINION IN PLANT BIOLOGY 2022; 66:102196. [PMID: 35219142 DOI: 10.1016/j.pbi.2022.102196] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/18/2022] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
Plants, as autotrophic organisms, capture light energy to convert carbon dioxide into ATP, NADPH, and sugars, which are essential for the biosynthesis of building blocks, cell proliferation, biomass accumulation, and reproductive fitness. The Target Of Rapamycin (TOR) signalling pathway is a master regulator in sensing energy and nutrients, adapting the metabolic network and cell behaviour in response to environmental resource availability. In the past years, exciting advances in this endeavour have pointed out this pathway's importance in controlling metabolic homeostasis in various biological processes and systems. In this review, we discuss these recent discoveries highlighting the need for a metabolic threshold for the proper function of this kinase complex at the cellular level and across distinct tissues and organs to control growth and development in plants.
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Affiliation(s)
- Anthony Artins
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
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8
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Coordination of Chloroplast Activity with Plant Growth: Clues Point to TOR. PLANTS 2022; 11:plants11060803. [PMID: 35336685 PMCID: PMC8953291 DOI: 10.3390/plants11060803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 11/17/2022]
Abstract
Photosynthesis is the defining function of most autotrophic organisms. In the plantae kingdom, chloroplasts host this function and ensure growth. However, these organelles are very sensitive to stressful conditions and the photosynthetic process can cause photooxidative damage if not perfectly regulated. In addition, their function is energivorous in terms of both chemical energy and nutrients. To coordinate chloroplast activity with the cell’s need, continuous signaling is required: from chloroplasts to cytoplasm and from nucleus to chloroplasts. In this opinion article, several mechanisms that ensure this communication are reported and the many clues that point to an important role of the Target of Rapamycin (TOR) kinase in the coordination between the eukaryotic and prokaryotic sides of plants are highlighted.
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9
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Whelehan LM, Funnekotter B, Bunn E, Mancera RL. Review: The case for studying mitochondrial function during plant cryopreservation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 315:111134. [PMID: 35067304 DOI: 10.1016/j.plantsci.2021.111134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/04/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Cryopreservation has several advantages over other ex situ conservation methods, and indeed is the only viable storage method for the long term conservation of most plant species. However, despite many advances in this field, it is increasingly clear that some species are ill-equipped to overcome the intense stress imposed by the cryopreservation process, making protocol development incredibly difficult using traditional trial and error methods. Cryobiotechnology approaches have been recently recognised as a strategic way forward, utilising intimate understanding of biological systems to inform development of more effective cryopreservation protocols. Mitochondrial function is a model candidate for a cryobiotechnological approach, as it underpins not only energy provision, but also several other key determinants of germplasm outcome, including stress response, reduction-oxidation status, and programmed cell death. Extensive research in animal cell and tissue cryopreservation has established a clear link between mitochondrial health and cryopreservation survival, but also indicates that mitochondria are routinely subject to damage from multiple aspects of the cryopreservation process. Evidence is already emerging that mitochondrial dysfunction may also occur in plant cryopreservation, and this research can be greatly expanded by using considered applications of innovative technologies. A range of mitochondria-targeted prophylactic and therapeutic interventions already exist with potential to improve cryopreservation outcomes through mitochondrial function.
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Affiliation(s)
- Lily M Whelehan
- Curtin Medical School, Curtin University, Perth, WA, Australia; Kings Park Science, Department of Biodiversity, Conservation and Attractions, Perth, WA, Australia.
| | - Bryn Funnekotter
- Curtin Medical School, Curtin University, Perth, WA, Australia; Kings Park Science, Department of Biodiversity, Conservation and Attractions, Perth, WA, Australia.
| | - Eric Bunn
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Perth, WA, Australia.
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10
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Couso I, Smythers AL, Ford MM, Umen JG, Crespo JL, Hicks LM. Inositol polyphosphates and target of rapamycin kinase signalling govern photosystem II protein phosphorylation and photosynthetic function under light stress in Chlamydomonas. THE NEW PHYTOLOGIST 2021; 232:2011-2025. [PMID: 34529857 DOI: 10.1111/nph.17741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 09/09/2021] [Indexed: 05/28/2023]
Abstract
Stress and nutrient availability influence cell proliferation through complex intracellular signalling networks. In a previous study it was found that pyro-inositol polyphosphates (InsP7 and InsP8 ) produced by VIP1 kinase, and target of rapamycin (TOR) kinase signalling interacted synergistically to control cell growth and lipid metabolism in the green alga Chlamydomonas reinhardtii. However, the relationship between InsPs and TOR was not completely elucidated. We used an in vivo assay for TOR activity together with global proteomic and phosphoproteomic analyses to assess differences between wild-type and vip1-1 in the presence and absence of rapamycin. We found that TOR signalling is more severely affected by the inhibitor rapamycin in a vip1-1 mutant compared with wild-type, indicating that InsP7 and InsP8 produced by VIP1 act independently but also coordinately with TOR. Additionally, among hundreds of differentially phosphorylated peptides detected, an enrichment for photosynthesis-related proteins was observed, particularly photosystem II proteins. The significance of these results was underscored by the finding that vip1-1 strains show multiple defects in photosynthetic physiology that were exacerbated under high light conditions. These results suggest a novel role for inositol pyrophosphates and TOR signalling in coordinating photosystem phosphorylation patterns in Chlamydomonas cells in response to light stress and possibly other stresses.
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Affiliation(s)
- Inmaculada Couso
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Avda. Américo Vespucio, 49, Sevilla, 41092, Spain
| | - Amanda L Smythers
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Megan M Ford
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - James G Umen
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Avda. Américo Vespucio, 49, Sevilla, 41092, Spain
| | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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11
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Song Y, Alyafei MS, Masmoudi K, Jaleel A, Ren M. Contributions of TOR Signaling on Photosynthesis. Int J Mol Sci 2021; 22:ijms22168959. [PMID: 34445664 PMCID: PMC8396432 DOI: 10.3390/ijms22168959] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/22/2021] [Accepted: 07/29/2021] [Indexed: 12/15/2022] Open
Abstract
The target of rapamycin (TOR) protein kinase is an atypical Ser/Thr protein kinase and evolutionally conserved among yeasts, plants, and mammals. TOR has been established as a central hub for integrating nutrient, energy, hormone, and environmental signals in all the eukaryotes. Despite the conserved functions across eukaryotes, recent research has shed light on the multifaceted roles of TOR signaling in plant-specific functional and mechanistic features. One of the most specific features is the involvement of TOR in plant photosynthesis. The recent development of tools for the functional analysis of plant TOR has helped to uncover the involvement of TOR signaling in several steps preceding photoautotrophy and maintenance of photosynthesis. Here, we present recent novel findings relating to TOR signaling and its roles in regulating plant photosynthesis, including carbon nutrient sense, light absorptions, and leaf and chloroplast development. We also provide some gaps in our understanding of TOR function in photosynthesis that need to be addressed in the future.
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Affiliation(s)
- Yun Song
- School of Life Sciences, Liaocheng University, Liaocheng 252000, China;
| | - Mohammed Salem Alyafei
- Department of Integrative Agriculture, College of Food and Agriculture, United Arab Emirates University, Al Ain 15551, United Arab Emirates; (M.S.A.); (K.M.); (A.J.)
| | - Khaled Masmoudi
- Department of Integrative Agriculture, College of Food and Agriculture, United Arab Emirates University, Al Ain 15551, United Arab Emirates; (M.S.A.); (K.M.); (A.J.)
| | - Abdul Jaleel
- Department of Integrative Agriculture, College of Food and Agriculture, United Arab Emirates University, Al Ain 15551, United Arab Emirates; (M.S.A.); (K.M.); (A.J.)
| | - Maozhi Ren
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China
- Correspondence: ; Tel.: +86-13527313471
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12
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da Silva VCH, Martins MCM, Calderan-Rodrigues MJ, Artins A, Monte Bello CC, Gupta S, Sobreira TJP, Riaño-Pachón DM, Mafra V, Caldana C. Shedding Light on the Dynamic Role of the "Target of Rapamycin" Kinase in the Fast-Growing C 4 Species Setaria viridis, a Suitable Model for Biomass Crops. FRONTIERS IN PLANT SCIENCE 2021; 12:637508. [PMID: 33927734 PMCID: PMC8078139 DOI: 10.3389/fpls.2021.637508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
The Target of Rapamycin (TOR) kinase pathway integrates energy and nutrient availability into metabolism promoting growth in eukaryotes. The overall higher efficiency on nutrient use translated into faster growth rates in C4 grass plants led to the investigation of differential transcriptional and metabolic responses to short-term chemical TOR complex (TORC) suppression in the model Setaria viridis. In addition to previously described responses to TORC inhibition (i.e., general growth arrest, translational repression, and primary metabolism reprogramming) in Arabidopsis thaliana (C3), the magnitude of changes was smaller in S. viridis, particularly regarding nutrient use efficiency and C allocation and partitioning that promote biosynthetic growth. Besides photosynthetic differences, S. viridis and A. thaliana present several specificities that classify them into distinct lineages, which also contribute to the observed alterations mediated by TOR. Indeed, cell wall metabolism seems to be distinctly regulated according to each cell wall type, as synthesis of non-pectic polysaccharides were affected in S. viridis, whilst assembly and structure in A. thaliana. Our results indicate that the metabolic network needed to achieve faster growth seems to be less stringently controlled by TORC in S. viridis.
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Affiliation(s)
| | | | | | - Anthony Artins
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | | | - Saurabh Gupta
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany
| | | | | | - Valéria Mafra
- National Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Camila Caldana
- National Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
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13
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A Tour of TOR Complex Signaling in Plants. Trends Biochem Sci 2020; 46:417-428. [PMID: 33309324 DOI: 10.1016/j.tibs.2020.11.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/26/2020] [Accepted: 11/09/2020] [Indexed: 01/07/2023]
Abstract
To identify the appropriate times for growth and development, organisms must sense and process information about the availability of nutrients, energy status, and environmental cues. For sessile eukaryotes such as plants, integrating such information can be critical in life or death decisions. For nearly 30 years, the conserved phosphatidylinositol 3-kinase-related protein kinases (PIKKs) target of rapamycin (TOR) has been established as a central hub for integrating external and internal metabolic cues. Despite the functional conservation across eukaryotes, the TOR complex has evolved specific functional and mechanistic features in plants. Here, we present recent findings on the plant TOR complex that highlight the conserved and unique nature of this critical growth regulator and its role in multiple aspects of plant life.
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14
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Brunkard JO. Exaptive Evolution of Target of Rapamycin Signaling in Multicellular Eukaryotes. Dev Cell 2020; 54:142-155. [PMID: 32649861 PMCID: PMC7346820 DOI: 10.1016/j.devcel.2020.06.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/12/2020] [Accepted: 06/18/2020] [Indexed: 12/16/2022]
Abstract
Target of rapamycin (TOR) is a protein kinase that coordinates metabolism with nutrient and energy availability in eukaryotes. TOR and its primary interactors, RAPTOR and LST8, have been remarkably evolutionarily static since they arose in the unicellular last common ancestor of plants, fungi, and animals, but the upstream regulatory mechanisms and downstream effectors of TOR signaling have evolved considerable diversity in these separate lineages. Here, I focus on the roles of exaptation and adaptation in the evolution of novel signaling axes in the TOR network in multicellular eukaryotes, concentrating especially on amino acid sensing, cell-cell signaling, and cell differentiation.
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Affiliation(s)
- Jacob O. Brunkard
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA,Plant Gene Expression Center, U.S. Department of Agriculture Agricultural Research Service, Albany, CA 94710, USA,Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA,Corresponding author
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