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Fujiwara T, Hirooka S, Yamashita S, Yagisawa F, Miyagishima SY. Development of a rapamycin-inducible protein-knockdown system in the unicellular red alga Cyanidioschyzon merolae. PLANT PHYSIOLOGY 2024; 196:77-94. [PMID: 38833589 PMCID: PMC11376382 DOI: 10.1093/plphys/kiae316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 04/25/2024] [Accepted: 05/14/2024] [Indexed: 06/06/2024]
Abstract
An inducible protein-knockdown system is highly effective for investigating the functions of proteins and mechanisms essential for the survival and growth of organisms. However, this technique is not available in photosynthetic eukaryotes. The unicellular red alga Cyanidioschyzon merolae possesses a very simple cellular and genomic architecture and is genetically tractable but lacks RNA interference machinery. In this study, we developed a protein-knockdown system in this alga. The constitutive system utilizes the destabilizing activity of the FK506-binding protein 12 (FKBP12)-rapamycin-binding (FRB) domain of human target of rapamycin kinase or its derivatives to knock down target proteins. In the inducible system, rapamycin treatment induces the heterodimerization of the human FRB domain fused to the target proteins with the human FKBP fused to S-phase kinase-associated protein 1 or Cullin 1, subunits of the SCF E3 ubiquitin ligase. This results in the rapid degradation of the target proteins through the ubiquitin-proteasome pathway. With this system, we successfully degraded endogenous essential proteins such as the chloroplast division protein dynamin-related protein 5B and E2 transcription factor, a regulator of the G1/S transition, within 2 to 3 h after rapamycin administration, enabling the assessment of resulting phenotypes. This rapamycin-inducible protein-knockdown system contributes to the functional analysis of genes whose disruption leads to lethality.
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Affiliation(s)
- Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka 411-8540, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Shizuoka 411-8540, Japan
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka 411-8540, Japan
| | - Shota Yamashita
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka 411-8540, Japan
| | - Fumi Yagisawa
- Research Facility Center, University of the Ryukyus, Okinawa 903-0213, Japan
| | - Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka 411-8540, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Shizuoka 411-8540, Japan
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2
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Testi S, Kuhn ML, Allasia V, Auroy P, Kong F, Peltier G, Pagnotta S, Cazareth J, Keller H, Panabières F. The Phytophthora parasitica effector AVH195 interacts with ATG8, attenuates host autophagy, and promotes biotrophic infection. BMC Biol 2024; 22:100. [PMID: 38679707 PMCID: PMC11057187 DOI: 10.1186/s12915-024-01899-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/22/2024] [Indexed: 05/01/2024] Open
Abstract
BACKGROUND Plant pathogens secrete effector proteins into host cells to suppress immune responses and manipulate fundamental cellular processes. One of these processes is autophagy, an essential recycling mechanism in eukaryotic cells that coordinates the turnover of cellular components and contributes to the decision on cell death or survival. RESULTS We report the characterization of AVH195, an effector from the broad-spectrum oomycete plant pathogen, Phytophthora parasitica. We show that P. parasitica expresses AVH195 during the biotrophic phase of plant infection, i.e., the initial phase in which host cells are maintained alive. In tobacco, the effector prevents the initiation of cell death, which is caused by two pathogen-derived effectors and the proapoptotic BAX protein. AVH195 associates with the plant vacuolar membrane system and interacts with Autophagy-related protein 8 (ATG8) isoforms/paralogs. When expressed in cells from the green alga, Chlamydomonas reinhardtii, the effector delays vacuolar fusion and cargo turnover upon stimulation of autophagy, but does not affect algal viability. In Arabidopsis thaliana, AVH195 delays the turnover of ATG8 from endomembranes and promotes plant susceptibility to P. parasitica and the obligate biotrophic oomycete pathogen Hyaloperonospora arabidopsidis. CONCLUSIONS Taken together, our observations suggest that AVH195 targets ATG8 to attenuate autophagy and prevent associated host cell death, thereby favoring biotrophy during the early stages of the infection process.
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Affiliation(s)
- Serena Testi
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech, 06903, Sophia Antipolis, France
- Present Address: Station Biologique de Roscoff, UMR8227 LBI2M, CNRS-Sorbonne Unversité, 29680, Roscoff, France
| | - Marie-Line Kuhn
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech, 06903, Sophia Antipolis, France
| | - Valérie Allasia
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech, 06903, Sophia Antipolis, France
| | - Pascaline Auroy
- Aix Marseille Université, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, 13108, Saint Paul-Lez-Durance, France
| | - Fantao Kong
- Aix Marseille Université, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, 13108, Saint Paul-Lez-Durance, France
- Present address: School of Bioengineering, Dalian University of Technology, Dalian, 116024, China
| | - Gilles Peltier
- Aix Marseille Université, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, 13108, Saint Paul-Lez-Durance, France
| | - Sophie Pagnotta
- Université Côte d'Azur, Centre Commun de Microscopie Appliquée, 06108, Nice, France
| | - Julie Cazareth
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 06903, Sophia Antipolis, France
| | - Harald Keller
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech, 06903, Sophia Antipolis, France.
| | - Franck Panabières
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech, 06903, Sophia Antipolis, France
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Rabeh K, Oubohssaine M, Hnini M. TOR in plants: Multidimensional regulators of plant growth and signaling pathways. JOURNAL OF PLANT PHYSIOLOGY 2024; 294:154186. [PMID: 38330538 DOI: 10.1016/j.jplph.2024.154186] [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: 09/01/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/10/2024]
Abstract
Target Of Rapamycin (TOR) represents a ubiquitous kinase complex that has emerged as a central regulator of cell growth and metabolism in nearly all eukaryotic organisms. TOR is an evolutionarily conserved protein kinase, functioning as a central signaling hub that integrates diverse internal and external cues to regulate a multitude of biological processes. These processes collectively exert significant influence on plant growth, development, nutrient assimilation, photosynthesis, fruit ripening, and interactions with microorganisms. Within the plant domain, the TOR complex comprises three integral components: TOR, RAPTOR, and LST8. This comprehensive review provides insights into various facets of the TOR protein, encompassing its origin, structure, function, and the regulatory and signaling pathways operative in photosynthetic organisms. Additionally, we explore future perspectives related to this pivotal protein kinase.
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Affiliation(s)
- Karim Rabeh
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco.
| | - Malika Oubohssaine
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco
| | - Mohamed Hnini
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco
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Guo J, Yao Q, Dong J, Hou J, Jia P, Chen X, Li G, Zhao Q, Wang J, Liu F, Wang Z, Shan Y, Zhang T, Fu A, Wang F. Immunophilin FKB20-2 participates in oligomerization of Photosystem I in Chlamydomonas. PLANT PHYSIOLOGY 2024; 194:1631-1645. [PMID: 38039102 DOI: 10.1093/plphys/kiad645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 10/26/2023] [Accepted: 11/05/2023] [Indexed: 12/03/2023]
Abstract
PSI is a sophisticated photosynthesis protein complex that fuels the light reaction of photosynthesis in algae and vascular plants. While the structure and function of PSI have been studied extensively, the dynamic regulation on PSI oligomerization and high light response is less understood. In this work, we characterized a high light-responsive immunophilin gene FKB20-2 (FK506-binding protein 20-2) required for PSI oligomerization and high light tolerance in Chlamydomonas (Chlamydomonas reinhardtii). Biochemical assays and 77-K fluorescence measurement showed that loss of FKB20-2 led to the reduced accumulation of PSI core subunits and abnormal oligomerization of PSI complexes and, particularly, reduced PSI intermediate complexes in fkb20-2. It is noteworthy that the abnormal PSI oligomerization was observed in fkb20-2 even under dark and dim light growth conditions. Coimmunoprecipitation, MS, and yeast 2-hybrid assay revealed that FKB20-2 directly interacted with the low molecular weight PSI subunit PsaG, which might be involved in the dynamic regulation of PSI-light-harvesting complex I supercomplexes. Moreover, abnormal PSI oligomerization caused accelerated photodamage to PSII in fkb20-2 under high light stress. Together, we demonstrated that immunophilin FKB20-2 affects PSI oligomerization probably by interacting with PsaG and plays pivotal roles during Chlamydomonas tolerance to high light.
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Affiliation(s)
- Jia Guo
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Qiang Yao
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Jie Dong
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Jinrong Hou
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Pulian Jia
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Xueying Chen
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Guoyang Li
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Qi Zhao
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
- Shaanxi Key Laboratory for Carbon Neutral Technology, Xi'an 710069, China
| | - Jingyi Wang
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
- Shaanxi Key Laboratory for Carbon Neutral Technology, Xi'an 710069, China
| | - Fang Liu
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Ziyu Wang
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Yuying Shan
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Tengyue Zhang
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
| | - Aigen Fu
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
- Shaanxi Key Laboratory for Carbon Neutral Technology, Xi'an 710069, China
| | - Fei Wang
- College of Life Sciences, Northwest University, Xi'an 710069, China
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China
- Shaanxi Key Laboratory for Carbon Neutral Technology, Xi'an 710069, China
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Wang Y, Wakelam MJO, Bankaitis VA, McDermott MI. The wide world of non-mammalian phospholipase D enzymes. Adv Biol Regul 2024; 91:101000. [PMID: 38081756 DOI: 10.1016/j.jbior.2023.101000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 02/25/2024]
Abstract
Phospholipase D (PLD) hydrolyses phosphatidylcholine (PtdCho) to produce free choline and the critically important lipid signaling molecule phosphatidic acid (PtdOH). Since the initial discovery of PLD activities in plants and bacteria, PLDs have been identified in a diverse range of organisms spanning the taxa. While widespread interest in these proteins grew following the discovery of mammalian isoforms, research into the PLDs of non-mammalian organisms has revealed a fascinating array of functions ranging from roles in microbial pathogenesis, to the stress responses of plants and the developmental patterning of flies. Furthermore, studies in non-mammalian model systems have aided our understanding of the entire PLD superfamily, with translational relevance to human biology and health. Increasingly, the promise for utilization of non-mammalian PLDs in biotechnology is also being recognized, with widespread potential applications ranging from roles in lipid synthesis, to their exploitation for agricultural and pharmaceutical applications.
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Affiliation(s)
- Y Wang
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA; Department of Microbiology, University of Washington, Seattle, WA98109, USA
| | - M J O Wakelam
- Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, United Kingdom
| | - V A Bankaitis
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA; Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX, 77843, USA; Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - M I McDermott
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA.
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6
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Hernández-García CI, Martínez-Jerónimo F. Changes in the morphology and cell ultrastructure of a microalgal community exposed to a commercial glyphosate formulation and a toxigenic cyanobacterium. Front Microbiol 2023; 14:1195776. [PMID: 37426024 PMCID: PMC10324582 DOI: 10.3389/fmicb.2023.1195776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/05/2023] [Indexed: 07/11/2023] Open
Abstract
Human activities significantly influence the health of aquatic ecosystems because many noxious chemical wastes are discharged into freshwater bodies. Intensive agriculture contributes to the deterioration by providing indirectly fertilizers, pesticides, and other agrochemicals that affect the aquatic biota. Glyphosate is one of the most used herbicides worldwide, and microalgae are particularly sensitive to its formulation, inducing displacement of some green microalgae from the phytoplankton that leads to alterations in the floristic composition, which fosters the abundance of cyanobacteria, some of which can be toxigenic. The combination of chemical stressors such as glyphosate and biological ones, like cyanotoxins and other secondary metabolites of cyanobacteria, could induce a combined effect potentially more noxious to microalgae, affecting not only their growth but also their physiology and morphology. In this study, we evaluated the combined effect of glyphosate (Faena®) and a toxigenic cyanobacterium on the morphology and ultrastructure of microalgae in an experimental phytoplankton community. For this purpose, Microcystis aeruginosa (a cosmopolitan cyanobacterium that forms harmful blooms) and the microalgae Ankistrodesmus falcatus, Chlorella vulgaris, Pseudokirchneriella subcapitata, and Scenedesmus incrassatulus were cultivated, individually and jointly, exposing them to sub-inhibitory concentrations of glyphosate (IC10, IC20, and IC40). Effects were evaluated through scanning electron (SEM) and transmission electron (TEM) microscopy. Exposure to Faena® produced alterations in the external morphology and ultrastructure of microalgae both individually and in combined cultures. SEM evidenced the loss of the typical shape and integrity of the cell wall and an increase in the biovolume. TEM revealed reduction and disorganization of the chloroplast, variation in starch and polyphosphate granules, formation of vesicles and vacuoles, cytoplasm degradation, and cell wall continuity loss. The presence of M. aeruginosa was, for microalgae, an additional stress factor adding to the chemical stress produced by Faena®, increasing the damage in their morphology and ultrastructure. These results alert to the effects that can be caused by glyphosate and the presence of toxigenic bacteria on the algal phytoplankton in contaminated and anthropic and eutrophic freshwater ecosystems.
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Dobesova M, Kolackova M, Pencik O, Capal P, Chaloupsky P, Svec P, Ridoskova A, Motola M, Cicmancova V, Sopha H, Macak JM, Richtera L, Adam V, Huska D. Transcriptomic hallmarks of in vitro TiO 2 nanotubes toxicity in Chlamydomonas reinhardtii. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2023; 256:106419. [PMID: 36807021 DOI: 10.1016/j.aquatox.2023.106419] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Recently, more accessible transcriptomic approaches have provided a new and deeper understanding of environmental toxicity. The present study focuses on the transcriptomic profiles of green microalgae Chlamydomonas reinhardtii exposed to new industrially promising material, TiO2 nanotubes (NTs), as an example of a widely used one-dimensional nanomaterial. The first algal in vitro assay included 2.5 and 7.5 mg/L TiO2 NTs, resulting in a dose-dependent negative effect on biological endpoints. At a working concentration of 7.5 mg/L, RNA-sequencing showed a mainly negative effect on the cells. In summary, the results indicated metabolic disruption, such as ATP loss, damage to mitochondria and chloroplasts, loss of solutes due to permeated membranes, and cell wall damage. Moreover, apoptosis-induced transcripts were detected. Interestingly, reactivation of transposons was observed. In signalling and transcription pathways, including chromatin remodelling and locking, the annotated genes were downregulated.
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Affiliation(s)
- Marketa Dobesova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Martina Kolackova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Ondrej Pencik
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Petr Capal
- Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Slechtitelu 241/27, 783 71, Olomouc, Czech Republic
| | - Pavel Chaloupsky
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Pavel Svec
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic; Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic
| | - Andrea Ridoskova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Martin Motola
- Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. Legii 565, 530 02 Pardubice, Czech Republic
| | - Veronika Cicmancova
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic; Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. Legii 565, 530 02 Pardubice, Czech Republic
| | - Hanna Sopha
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic; Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. Legii 565, 530 02 Pardubice, Czech Republic
| | - Jan M Macak
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic; Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. Legii 565, 530 02 Pardubice, Czech Republic
| | - Lukas Richtera
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic; Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic
| | - Vojtech Adam
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Dalibor Huska
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic.
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Morales-Pineda M, García-Gómez ME, Bedera-García R, García-González M, Couso I. CO 2 Levels Modulate Carbon Utilization, Energy Levels and Inositol Polyphosphate Profile in Chlorella. PLANTS (BASEL, SWITZERLAND) 2022; 12:plants12010129. [PMID: 36616258 PMCID: PMC9823770 DOI: 10.3390/plants12010129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 05/15/2023]
Abstract
Microalgae have a growing recognition of generating biomass and capturing carbon in the form of CO2. The genus Chlorella has especially attracted scientists' attention due to its versatility in algal mass cultivation systems and its potential in mitigating CO2. However, some aspects of how these green microorganisms respond to increasing concentrations of CO2 remain unclear. In this work, we analyzed Chlorella sorokiniana and Chlorella vulgaris cells under low and high CO2 levels. We monitored different processes related to carbon flux from photosynthetic capacity to carbon sinks. Our data indicate that high concentration of CO2 favors growth and photosynthetic capacity of the two Chlorella strains. Different metabolites related to the tricarboxylic acid cycle and ATP levels also increased under high CO2 concentrations in Chlorella sorokiniana, reaching up to two-fold compared to low CO2 conditions. The signaling molecules, inositol polyphosphates, that regulate photosynthetic capacity in green microalgae were also affected by the CO2 levels, showing a deep profile modification of the inositol polyphosphates that over-accumulated by up to 50% in high CO2 versus low CO2 conditions. InsP4 and InsP6 increased 3- and 0.8-fold, respectively, in Chlorella sorokiniana after being subjected to 5% CO2 condition. These data indicate that the availability of CO2 could control carbon flux from photosynthesis to carbon storage and impact cell signaling integration and energy levels in these green cells. The presented results support the importance of further investigating the connections between carbon assimilation and cell signaling by polyphosphate inositols in microalgae to optimize their biotechnological applications.
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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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The Rheb GTPase promotes pheromone blindness via a TORC1-independent pathway in the phytopathogenic fungus Ustilago maydis. PLoS Genet 2022; 18:e1010483. [DOI: 10.1371/journal.pgen.1010483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 11/28/2022] [Accepted: 10/17/2022] [Indexed: 11/15/2022] Open
Abstract
The target of the rapamycin (TOR) signaling pathway plays a negative role in controlling virulence in phytopathogenic fungi. However, the actual targets involved in virulence are currently unknown. Using the corn smut fungus Ustilago maydis, we tried to address the effects of the ectopic activation of TOR on virulence. We obtained gain-of-function mutations in the Rheb GTPase, one of the conserved TOR kinase regulators. We have found that unscheduled activation of Rheb resulted in the alteration of the proper localization of the pheromone receptor, Pra1, and thereby pheromone insensitivity. Since pheromone signaling triggers virulence in Ustilaginales, we believe that the Rheb-induced pheromone blindness was responsible for the associated lack of virulence. Strikingly, although these effects required the concourse of the Rsp5 ubiquitin ligase and the Art3 α-arrestin, the TOR kinase was not involved. Several eukaryotic organisms have shown that Rheb transmits environmental information through TOR-dependent and -independent pathways. Therefore, our results expand the range of signaling manners at which environmental conditions could impinge on the virulence of phytopathogenic fungi.
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Caló G, De Marco MA, Salerno GL, Martínez-Noël GMA. TOR signaling in the green picoalga Ostreococcus tauri. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 323:111390. [PMID: 35868347 DOI: 10.1016/j.plantsci.2022.111390] [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: 04/08/2022] [Revised: 06/29/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Target of rapamycin (TOR) is a master regulator that controls growth and metabolism by integrating external and internal signals. Although there was a great progress in the study of TOR in plants and in the model alga Chlamydomonas, scarce data are available in other green algae. Thus, in this work we studied TOR signaling in Ostreococcus tauri, the smallest free-living eukaryote described to date. This picoalga is particularly important because it has a key site at the base of the green lineage and is part of the marine phytoplankton, contributing to global photosynthesis. We investigated OtTOR complex in silico and experimentally, by using first- and second-generation TOR inhibitors, such as rapamycin and PP242. We analyzed the effect of TOR down-regulation on cell growth and on the accumulation of carbon reserves. The results showed that O. tauri responds to TOR inhibitors more similarly to plants than to Chlamydomonas, being PP242 a valuable tool to study this pathway. Besides, Ottor expression analysis revealed that the kinase is dynamically regulated under nutritional stress. Our data indicate that TOR signaling is conserved in O. tauri and we propose this alga as a good and simple model for studying TOR kinase and its regulation.
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Affiliation(s)
- Gonzalo Caló
- INBIOTEC, Vieytes, 3103, 7600 Mar del Plata, Argentina; FIBA, Vieytes 3103, 7600 Mar del Plata, Argentina
| | - María Agustina De Marco
- INBIOTEC, Vieytes, 3103, 7600 Mar del Plata, Argentina; FIBA, Vieytes 3103, 7600 Mar del Plata, Argentina
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12
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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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13
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Haq SIU, Shang J, Xie H, Qiu QS. Roles of TOR signaling in nutrient deprivation and abiotic stress. JOURNAL OF PLANT PHYSIOLOGY 2022; 274:153716. [PMID: 35597106 DOI: 10.1016/j.jplph.2022.153716] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/25/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
In living organisms, nutrient, energy, and environmental stimuli sensing and signaling are considered as the most primordial regulatory networks governing growth and development. Target of Rapamycin (TOR) is a diversified Serine/Threonine protein kinase existing in all eukaryotes that regulates distinct salient growth and developmental signaling pathways. TOR signaling acts as a central hub in plants that allows a variety of nutrients, energy, hormones, and environmental stimuli to be integrated. TOR is activated by several nutrients and promotes energy-consuming processes such as cell division, protein translation, mRNA translation and ribosome biogenesis. We summarized the recent findings on the TOR function in regulating the dynamic networks of nutrients, including sugar, sulfur, nitrogen, carbon, phosphorus, potassium, and amino acids. TOR's role in abiotic stress was discussed, in which TOR orchestrating stress signaling, including heat, cold, salt, and osmotic stress, to regulate transcriptional and metabolic reprogramming, as well as growth and development. The interconnections between TOR and SnRK1 kinase were discussed in controlling nutrient deprivation and abiotic stress.
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Affiliation(s)
- Syed Inzimam Ul Haq
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Jun Shang
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810000, China; Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau, Xining, Qinghai, 810008, China
| | - Huichun Xie
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810000, China; Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau, Xining, Qinghai, 810008, China
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China; Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810000, China.
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14
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Abstract
The target of rapamycin (TOR) kinase is a master regulator that integrates nutrient signals to promote cell growth in all eukaryotes. It is well established that amino acids and glucose are major regulators of TOR signaling in yeast and metazoan, but whether and how TOR responds to carbon availability in photosynthetic organisms is less understood. In this study, we showed that photosynthetic assimilation of CO2 by the Calvin-Benson-Bassham (CBB) cycle regulates TOR activity in the model single-celled microalga Chlamydomonas reinhardtii Stimulation of CO2 fixation boosted TOR activity, whereas inhibition of the CBB cycle and photosynthesis down-regulated TOR. We uncovered a tight link between TOR activity and the endogenous level of a set of amino acids including Ala, Glu, Gln, Leu, and Val through the modulation of CO2 fixation and the use of amino acid synthesis inhibitors. Moreover, the finding that the Chlamydomonas starch-deficient mutant sta6 displayed disproportionate TOR activity and high levels of most amino acids, particularly Gln, further connected carbon assimilation and amino acids to TOR signaling. Thus, our results showed that CO2 fixation regulates TOR signaling, likely through the synthesis of key amino acids.
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15
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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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16
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Ji H, Yu Z, He L, Zhu J, Cao X, Song X. Programmed cell death induced by modified clay in controlling Prorocentrum donghaiense bloom. J Environ Sci (China) 2021; 109:123-134. [PMID: 34607661 DOI: 10.1016/j.jes.2021.03.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 06/13/2023]
Abstract
Modified clay (MC), an effective material used for the emergency elimination of algal blooms, can rapidly reduce the biomass of harmful algal blooms (HABs) via flocculation. After that, MC can still control bloom population through indirect effects such as oxidative stress, which was initially proposed to be related to programmed cell death (PCD) at molecular level. To further study the MC induced cell death in residual bloom organisms, especially identifying PCD process, we studied the physiological state of the residual Prorocentrum donghaiense. The experimental results showed that flocculation changed the physiological state of the residual cells, as evidenced by growth inhibition and increased reactive oxygen species production. Moreover, this research provides biochemical and ultrastructural evidence showing that MC induces PCD in P. donghaiense. Nuclear changes were observed, and increased caspase-like activity, externalization of phosphatidylserine and DNA fragmentation were detected in MC-treated groups and quantified. And the mitochondrial apoptosis pathway was activated in both MC-treated groups. Besides, the features of MC-induced PCD in a unicellular organism were summarized and its concentration dependent manner was proved. All our preliminary results elucidate the mechanism through which MC can further control HABs by inducing PCD and suggest a promising application of PCD in bloom control.
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Affiliation(s)
- Hena Ji
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Zhiming Yu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Liyan He
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Jianan Zhu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Xihua Cao
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Xiuxian Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
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17
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Luo X, Tian T, Bonnave M, Tan X, Huang X, Li Z, Ren M. The Molecular Mechanisms of Phytophthora infestans in Response to Reactive Oxygen Species Stress. PHYTOPATHOLOGY 2021; 111:2067-2079. [PMID: 33787286 DOI: 10.1094/phyto-08-20-0321-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Reactive oxygen species (ROSs) are critical for the growth, development, proliferation, and pathogenicity of microbial pathogens; however, excessive levels of ROSs are toxic. Little is known about the signaling cascades in response to ROS stress in oomycetes such as Phytophthora infestans, the causal agent of potato late blight. Here, P. infestans was used as a model system to investigate the mechanism underlying the response to ROS stress in oomycete pathogens. Results showed severe defects in sporangium germination, mycelium growth, appressorium formation, and virulence of P. infestans in response to H2O2 stress. Importantly, these phenotypes mimic those of P. infestans treated with rapamycin, the inhibitor of target of rapamycin (TOR, 1-phosphatidylinositol-3-kinase). Strong synergism occurred when P. infestans was treated with a combination of H2O2 and rapamycin, suggesting that a crosstalk exists between ROS stress and the TOR signaling pathway. Comprehensive analysis of transcriptome, proteome, and phosphorylation omics showed that H2O2 stress significantly induced the operation of the TOR-mediated autophagy pathway. Monodansylcadaverine staining showed that in the presence of H2O2 and rapamycin, the autophagosome level increased in a dosage-dependent manner. Furthermore, transgenic potatoes containing double-stranded RNA of TOR in P. infestans (PiTOR) displayed high resistance to P. infestans. Therefore, TOR is involved in the ROS response and is a potential target for control of oomycete diseases, because host-mediated silencing of PiTOR increases potato resistance to late blight.
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Affiliation(s)
- Xiumei Luo
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610000, China
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Tingting Tian
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Maxime Bonnave
- Centre for Agriculture and Agro-Industry of Hainaut Province, Ath 7800, Belgium
| | - Xue Tan
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Xiaoqing Huang
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Zhengguo Li
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Maozhi Ren
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610000, China
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou 450000, China
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18
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Muñoz-Muñoz PLA, Mares-Alejandre RE, Meléndez-López SG, Ramos-Ibarra MA. Bioinformatic Analysis of Two TOR (Target of Rapamycin)-Like Proteins Encoded by Entamoeba histolytica Revealed Structural Similarities with Functional Homologs. Genes (Basel) 2021; 12:genes12081139. [PMID: 34440318 PMCID: PMC8391992 DOI: 10.3390/genes12081139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/21/2021] [Accepted: 07/24/2021] [Indexed: 01/04/2023] Open
Abstract
The target of rapamycin (TOR), also known as FKBP-rapamycin associated protein (FRAP), is a protein kinase belonging to the PIKK (phosphatidylinositol 3-kinase (PI3K)-related kinases) family. TOR kinases are involved in several signaling pathways that control cell growth and proliferation. Entamoeba histolytica, the protozoan parasite that causes human amoebiasis, contains two genes encoding TOR-like proteins: EhFRAP and EhTOR2. To assess their potential as drug targets to control the cell proliferation of E. histolytica, we studied the structural features of EhFRAP and EhTOR2 using a biocomputational approach. The overall results confirmed that both TOR amoebic homologs share structural similarities with functional TOR kinases, and show inherent abilities to form TORC complexes and participate in protein-protein interaction networks. To our knowledge, this study represents the first in silico characterization of the structure-function relationships of EhFRAP and EhTOR2.
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19
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Pancha I, Takaya K, Tanaka K, Imamura S. The Unicellular Red Alga Cyanidioschyzon merolae, an Excellent Model Organism for Elucidating Fundamental Molecular Mechanisms and Their Applications in Biofuel Production. PLANTS 2021; 10:plants10061218. [PMID: 34203949 PMCID: PMC8232737 DOI: 10.3390/plants10061218] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 11/16/2022]
Abstract
Microalgae are considered one of the best resources for the production of biofuels and industrially important compounds. Various models have been developed to understand the fundamental mechanism underlying the accumulation of triacylglycerols (TAGs)/starch and to enhance its content in cells. Among various algae, the red alga Cyanidioschyzonmerolae has been considered an excellent model system to understand the fundamental mechanisms behind the accumulation of TAG/starch in the microalga, as it has a smaller genome size and various biotechnological methods are available for it. Furthermore, C. merolae can grow and survive under high temperature (40 °C) and low pH (2–3) conditions, where most other organisms would die, thus making it a choice alga for large-scale production. Investigations using this alga has revealed that the target of rapamycin (TOR) kinase is involved in the accumulation of carbon-reserved molecules, TAGs, and starch. Furthermore, detailed molecular mechanisms of the role of TOR in controlling the accumulation of TAGs and starch were uncovered via omics analyses. Based on these findings, genetic engineering of the key gene and proteins resulted in a drastic increment of the amount of TAGs and starch. In addition to these studies, other trials that attempted to achieve the TAG increment in C. merolae have been summarized in this article.
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Affiliation(s)
- Imran Pancha
- Department of Biological Sciences, SRM University-AP, Amaravati, Andhra Pradesh 522502, India
- Correspondence: (I.P.); (S.I.); Tel.: +81-422-59-6179 (S.I.)
| | - Kazuhiro Takaya
- NTT Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, 3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan;
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama-shi, Kanagawa 226-8503, Japan;
| | - Sousuke Imamura
- NTT Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, 3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan;
- Correspondence: (I.P.); (S.I.); Tel.: +81-422-59-6179 (S.I.)
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20
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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: 9] [Impact Index Per Article: 3.0] [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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21
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Kang S, Jeon S, Kim S, Chang YK, Kim YC. Development of a pVEC peptide-based ribonucleoprotein (RNP) delivery system for genome editing using CRISPR/Cas9 in Chlamydomonas reinhardtii. Sci Rep 2020; 10:22158. [PMID: 33335164 PMCID: PMC7747696 DOI: 10.1038/s41598-020-78968-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 11/19/2020] [Indexed: 12/13/2022] Open
Abstract
Recent technical advances related to the CRISPR/Cas9-based genome editing system have enabled sophisticated genome editing in microalgae. Although the demand for research on genome editing in microalgae has increased over time, methodological research has not been established to date for the delivery of a ribonucleoprotein (Cas9/sgRNA complex) using a cell penetrating peptide into microalgal cell lines. Here, we present a ribonucleoprotein delivery system for Chlamydomonas reinhardtii mediated by the cell penetrating peptide pVEC (LLIILRRRIRKQAHAHSK) which is in a non-covalent form. Using this technically simple method, the ribonucleoprotein was successfully delivered into C. reinhardtii. Gene Maa7 and FKB12 were disrupted, and their distinguishing patterns of Indel mutations were analyzed with the observation of several insertions of sequences not originating from the genome DNA, such as chloroplast DNA, into the expected loci. In addition, the cytotoxicity of Cas9 and the ribonucleoprotein was investigated according to the concentration and time in the algal cells. It was observed that Cas9 alone without the sgRNA induces a more severe cytotoxicity compared to the ribonucleoprotein. Our study will not only contribute to algal cell biology and its genetic engineering for further applications involving various organisms but will also provide a deeper understating of the basic science of the CRISPR/Cas9 system.
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Affiliation(s)
- Seongsu Kang
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Republic of Korea
| | - Seungjib Jeon
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Republic of Korea
| | - Seungcheol Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Republic of Korea
| | - Yong Keun Chang
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Republic of Korea
| | - Yeu-Chun Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Republic of Korea.
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22
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Mugume Y, Kazibwe Z, Bassham DC. Target of Rapamycin in Control of Autophagy: Puppet Master and Signal Integrator. Int J Mol Sci 2020; 21:ijms21218259. [PMID: 33158137 PMCID: PMC7672647 DOI: 10.3390/ijms21218259] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023] Open
Abstract
The target of rapamycin (TOR) is an evolutionarily-conserved serine/threonine kinase that senses and integrates signals from the environment to coordinate developmental and metabolic processes. TOR senses nutrients, hormones, metabolites, and stress signals to promote cell and organ growth when conditions are favorable. However, TOR is inhibited when conditions are unfavorable, promoting catabolic processes such as autophagy. Autophagy is a macromolecular degradation pathway by which cells degrade and recycle cytoplasmic materials. TOR negatively regulates autophagy through phosphorylation of ATG13, preventing activation of the autophagy-initiating ATG1-ATG13 kinase complex. Here we review TOR complex composition and function in photosynthetic and non-photosynthetic organisms. We also review recent developments in the identification of upstream TOR activators and downstream effectors of TOR. Finally, we discuss recent developments in our understanding of the regulation of autophagy by TOR in photosynthetic organisms.
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23
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Ingargiola C, Turqueto Duarte G, Robaglia C, Leprince AS, Meyer C. The Plant Target of Rapamycin: A Conduc TOR of Nutrition and Metabolism in Photosynthetic Organisms. Genes (Basel) 2020; 11:genes11111285. [PMID: 33138108 PMCID: PMC7694126 DOI: 10.3390/genes11111285] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 12/15/2022] Open
Abstract
Living organisms possess many mechanisms to sense nutrients and favorable conditions, which allow them to grow and develop. Photosynthetic organisms are very diverse, from green unicellular algae to multicellular flowering plants, but most of them are sessile and thus unable to escape from the biotic and abiotic stresses they experience. The Target of Rapamycin (TOR) signaling pathway is conserved in all eukaryotes and acts as a central regulatory hub between growth and extrinsic factors, such as nutrients or stress. However, relatively little is known about the regulations and roles of this pathway in plants and algae. Although some features of the TOR pathway seem to have been highly conserved throughout evolution, others clearly differ in plants, perhaps reflecting adaptations to different lifestyles and the rewiring of this primordial signaling module to adapt to specific requirements. Indeed, TOR is involved in plant responses to a vast array of signals including nutrients, hormones, light, stresses or pathogens. In this review, we will summarize recent studies that address the regulations of TOR by nutrients in photosynthetic organisms, and the roles of TOR in controlling important metabolic pathways, highlighting similarities and differences with the other eukaryotes.
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Affiliation(s)
- Camille Ingargiola
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (C.I.); (G.T.D.); (A.-S.L.)
| | - Gustavo Turqueto Duarte
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (C.I.); (G.T.D.); (A.-S.L.)
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Christophe Robaglia
- Laboratoire de Génétique et Biophysique des Plantes, Faculté des Sciences de Luminy, UMR 7265, CEA, CNRS, BIAM, Aix Marseille Université, 13009 Marseille, France;
| | - Anne-Sophie Leprince
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (C.I.); (G.T.D.); (A.-S.L.)
- Faculté des Sciences et d’Ingénierie, Sorbonne Université, UFR 927, 4 Place Jussieu, 75252 Paris, France
| | - Christian Meyer
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (C.I.); (G.T.D.); (A.-S.L.)
- Correspondence:
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Smythers AL, McConnell EW, Lewis HC, Mubarek SN, Hicks LM. Photosynthetic Metabolism and Nitrogen Reshuffling Are Regulated by Reversible Cysteine Thiol Oxidation Following Nitrogen Deprivation in Chlamydomonas. PLANTS 2020; 9:plants9060784. [PMID: 32585825 PMCID: PMC7355495 DOI: 10.3390/plants9060784] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/01/2020] [Accepted: 06/19/2020] [Indexed: 12/13/2022]
Abstract
As global temperatures climb to historic highs, the far-reaching effects of climate change have impacted agricultural nutrient availability. This has extended to low latitude oceans, where a deficit in both nitrogen and phosphorus stores has led to dramatic decreases in carbon sequestration in oceanic phytoplankton. Although Chlamydomonas reinhardtii, a freshwater model green alga, has shown drastic systems-level alterations following nitrogen deprivation, the mechanisms through which these alterations are triggered and regulated are not fully understood. This study examined the role of reversible oxidative signaling in the nitrogen stress response of C. reinhardtii. Using oxidized cysteine resin-assisted capture enrichment coupled with label-free quantitative proteomics, 7889 unique oxidized cysteine thiol identifiers were quantified, with 231 significantly changing peptides from 184 proteins following 2 h of nitrogen deprivation. These results demonstrate that the cellular response to nitrogen assimilation, photosynthesis, pigment biosynthesis, and lipid metabolism are regulated by reversible oxidation. An enhanced role of non-damaging oxidative pathways is observed throughout the photosynthetic apparatus that provides a framework for further analysis in phototrophs.
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Pancha I, Chokshi K, Tanaka K, Imamura S. Microalgal Target of Rapamycin (TOR): A Central Regulatory Hub for Growth, Stress Response and Biomass Production. PLANT & CELL PHYSIOLOGY 2020; 61:675-684. [PMID: 32105317 DOI: 10.1093/pcp/pcaa023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
Target of rapamycin (TOR) is an evolutionarily conserved protein kinase that plays an important role in the regulation of cell growth and the sensing of nutrient and energy status in eukaryotes. In yeasts and mammals, the roles of TOR have been very well described and various functions of TOR signaling in plant lineages have also been revealed over the past 20 years. In the case of microalgae, the functions of TOR have been primarily studied in the model green alga Chlamydomonas reinhardtii and were summarized in an earlier single review article. However, the recent development of tools for the functional analysis of TOR has helped to reveal the involvement of TOR in various functions, including autophagy, transcription, translation, accumulation of energy storage molecules, etc., in microalgae. In the present review, we discuss recent novel findings relating to TOR signaling and its roles in microalgae along with relevant information on land plants and also provide details of topics that must be addressed in future studies to reveal how TOR regulates various physiological functions in microalgae.
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Affiliation(s)
- Imran Pancha
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
- Department of Biology, SRM University-AP, Amaravati, Andhra Pradesh 522502, India
| | - Kaumeel Chokshi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
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Serrano-Bueno G, Said FE, de Los Reyes P, Lucas-Reina EI, Ortiz-Marchena MI, Romero JM, Valverde F. CONSTANS-FKBP12 interaction contributes to modulation of photoperiodic flowering in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:1287-1302. [PMID: 31661582 DOI: 10.1111/tpj.14590] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/21/2019] [Indexed: 05/22/2023]
Abstract
Flowering time is a key process in plant development. Photoperiodic signals play a crucial role in the floral transition in Arabidopsis thaliana, and the protein CONSTANS (CO) has a central regulatory function that is tightly regulated at the transcriptional and post-translational levels. The stability of CO protein depends on a light-driven proteasome process that optimizes its accumulation in the evening to promote the production of the florigen FLOWERING LOCUS T (FT) and induce seasonal flowering. To further investigate the post-translational regulation of CO protein we have dissected its interactome network employing in vivo and in vitro assays and molecular genetics approaches. The immunophilin FKBP12 has been identified in Arabidopsis as a CO interactor that regulates its accumulation and activity. FKBP12 and CO interact through the CCT domain, affecting the stability and function of CO. fkbp12 insertion mutants show a delay in flowering time, while FKBP12 overexpression accelerates flowering, and these phenotypes can be directly related to a change in accumulation of FT protein. The interaction is conserved between the Chlamydomonas algal orthologs CrCO-CrFKBP12, revealing an ancient regulatory step in photoperiod regulation of plant development.
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Affiliation(s)
- Gloria Serrano-Bueno
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 49 Americo Vespucio, 41092, Sevilla, Spain
| | - Fatima E Said
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 49 Americo Vespucio, 41092, Sevilla, Spain
| | - Pedro de Los Reyes
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 49 Americo Vespucio, 41092, Sevilla, Spain
| | - Eva I Lucas-Reina
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 49 Americo Vespucio, 41092, Sevilla, Spain
| | - M Isabel Ortiz-Marchena
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 49 Americo Vespucio, 41092, Sevilla, Spain
| | - José M Romero
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 49 Americo Vespucio, 41092, Sevilla, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Reina Mercedes, 41012, Sevilla, Spain
| | - Federico Valverde
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 49 Americo Vespucio, 41092, Sevilla, Spain
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Kajikawa M, Fukuzawa H. Algal Autophagy Is Necessary for the Regulation of Carbon Metabolism Under Nutrient Deficiency. FRONTIERS IN PLANT SCIENCE 2020; 11:36. [PMID: 32117375 PMCID: PMC7012896 DOI: 10.3389/fpls.2020.00036] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/13/2020] [Indexed: 05/04/2023]
Abstract
Autophagy is a mechanism to recycle intracellular constituents such as amino acids and other carbon- and nitrogen (N)-containing compounds. Although autophagy-related (ATG) genes required for autophagy are encoded by many algal genomes, their functional importance in microalgae in nutrient-deficiency has not been appraised using ATG-defective mutants. Recently, by characterization of an insertional mutant of the ATG8 encoding a ubiquitin-like protein indispensable for autophagosome formation in a green alga Chlamydomonas reinhardtii, we have provided evidence that supports the following notions. ATG8 protein is required for the degradation of lipid droplets and triacylglycerol (TAG) triggered by resupply of N to cell culture in N-deficient conditions. ATG8 protein is also necessary for starch accumulation under phosphorus-deficient conditions. Algal autophagy is not necessary for inheritance of chloroplast and mitochondrial genomes. In this review, we discuss the physiological roles of algal autophagy associated with nutrient deficiency revealed by the genetic and biochemical analyses using disruption mutants and reagents that inhibit the fatty acid biosynthesis and vacuolar H+-ATPase.
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Couso I, Pérez-Pérez ME, Ford MM, Martínez-Force E, Hicks LM, Umen JG, Crespo JL. Phosphorus Availability Regulates TORC1 Signaling via LST8 in Chlamydomonas. THE PLANT CELL 2020; 32:69-80. [PMID: 31712405 PMCID: PMC6961625 DOI: 10.1105/tpc.19.00179] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 10/07/2019] [Accepted: 11/08/2019] [Indexed: 05/05/2023]
Abstract
Target of rapamycin complex 1 (TORC1) is a central regulator of cell growth. It balances anabolic and catabolic processes in response to nutrients, growth factors, and energy availability. Nitrogen- and carbon-containing metabolites have been shown to activate TORC1 in yeast, animals, and plants. Here, we show that phosphorus (P) regulates TORC1 signaling in the model green alga Chlamydomonas (Chlamydomonas reinhardtii) via LST8, a conserved TORC1 subunit that interacts with the kinase domain of TOR. P starvation results in a sharp decrease in LST8 abundance and downregulation of TORC1 activity. A hypomorphic lst8 mutation resulted in decreased LST8 abundance, and it both reduced TORC1 signaling and altered the cellular response to P starvation. Additionally, we found that LST8 levels and TORC1 activity were not properly regulated in a mutant defective in the transcription factor PSR1, which is the major mediator of P deprivation responses in Chlamydomonas. Unlike wild-type cells, the psr1 mutant failed to downregulate LST8 abundance and TORC1 activity when under P limitation. These results identify PSR1 as an upstream regulator of TORC1 and demonstrate that TORC1 is a key component in P signaling in Chlamydomonas.
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Affiliation(s)
- Inmaculada Couso
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla, 41092 Sevilla, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla, 41092 Sevilla, Spain
| | - Megan M Ford
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Enrique Martínez-Force
- Instituto de la Grasa (Consejo Superior de Investigaciones Científicas), Edificio 46, Campus Universitario Pablo de Olavide, 41013 Sevilla, Spain
| | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - James G Umen
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla, 41092 Sevilla, Spain
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29
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Ford MM, Smythers AL, McConnell EW, Lowery SC, Kolling DRJ, Hicks LM. Inhibition of TOR in Chlamydomonas reinhardtii Leads to Rapid Cysteine Oxidation Reflecting Sustained Physiological Changes. Cells 2019; 8:cells8101171. [PMID: 31569396 PMCID: PMC6829209 DOI: 10.3390/cells8101171] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/16/2019] [Accepted: 09/26/2019] [Indexed: 12/16/2022] Open
Abstract
The target of rapamycin (TOR) kinase is a master metabolic regulator with roles in nutritional sensing, protein translation, and autophagy. In Chlamydomonas reinhardtii, a unicellular green alga, TOR has been linked to the regulation of increased triacylglycerol (TAG) accumulation, suggesting that TOR or a downstream target(s) is responsible for the elusive “lipid switch” in control of increasing TAG accumulation under nutrient limitation. However, while TOR has been well characterized in mammalian systems, it is still poorly understood in photosynthetic systems, and little work has been done to show the role of oxidative signaling in TOR regulation. In this study, the TOR inhibitor AZD8055 was used to relate reversible thiol oxidation to the physiological changes seen under TOR inhibition, including increased TAG content. Using oxidized cysteine resin-assisted capture enrichment coupled with label-free quantitative proteomics, 401 proteins were determined to have significant changes in oxidation following TOR inhibition. These oxidative changes mirrored characterized physiological modifications, supporting the role of reversible thiol oxidation in TOR regulation of TAG production, protein translation, carbohydrate catabolism, and photosynthesis through the use of reversible thiol oxidation. The delineation of redox-controlled proteins under TOR inhibition provides a framework for further characterization of the TOR pathway in photosynthetic eukaryotes.
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Affiliation(s)
- Megan M Ford
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Amanda L Smythers
- Department of Chemistry, Marshall University, Huntington, WV 25755, USA.
| | - Evan W McConnell
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Sarah C Lowery
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | | | - Leslie M Hicks
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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30
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Tran QG, Yoon HR, Cho K, Lee SJ, Crespo JL, Ramanan R, Kim HS. Dynamic Interactions between Autophagosomes and Lipid Droplets in Chlamydomonas reinhardtii. Cells 2019; 8:E992. [PMID: 31466295 PMCID: PMC6769876 DOI: 10.3390/cells8090992] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 08/23/2019] [Accepted: 08/26/2019] [Indexed: 12/15/2022] Open
Abstract
Autophagy is a highly conserved catabolic process in eukaryotic cells by which waste cellular components are recycled to maintain growth in both favorable and stress conditions. Autophagy has been linked to lipid metabolism in microalgae; however, the mechanism underlying this interaction remains unclear. In this study, transgenic Chlamydomonas reinhardtii cells that stably express the red fluorescent protein (mCherry) tagged-ATG8 as an autophagy marker were established. By using this tool, we were able to follow the autophagy process in live microalgal cells under various conditions. Live-cell and transmission electron microscopy (TEM) imaging revealed physical contacts between lipid droplets and autophagic structures during the early stage of nitrogen starvation, while fusion of these two organelles was observed in prolonged nutritional deficiency, suggesting that an autophagy-related pathway might be involved in lipid droplet turnover in this alga. Our results thus shed light on the interplay between autophagy and lipid metabolism in C. reinhardtii, and this autophagy marker would be a valuable asset for further investigations on autophagic processes in microalgae.
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Affiliation(s)
- Quynh-Giao Tran
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
- Department of Environmental Biotechnology, KRIBB School of Biotechnology, University of Science and Technology, Daejeon 34113, Korea
| | - Hyang Ran Yoon
- Immunotherapy Convergence Research Center, KRIBB, Daejeon 34141, Korea
| | - Kichul Cho
- Environmental Safety Group, Korea Institute of Science and Technology (KIST) Europe, Campus E 7.1, 66123 Saarbrücken, Germany
| | - Seon-Jin Lee
- Environmental Disease Research Center, KRIBB, Daejeon 34141, Korea
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 41092 Sevilla, Spain
| | - Rishiram Ramanan
- Sustainable Resources Laboratory, Department of Environmental Science, Central University of Kerala, Kasaragod 671316, Kerala, India
| | - Hee-Sik Kim
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea.
- Department of Environmental Biotechnology, KRIBB School of Biotechnology, University of Science and Technology, Daejeon 34113, Korea.
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Prioretti L, Carriere F, Field B, Avilan L, Montané MH, Menand B, Gontero B. Targeting TOR signaling for enhanced lipid productivity in algae. Biochimie 2019; 169:12-17. [PMID: 31265860 DOI: 10.1016/j.biochi.2019.06.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/26/2019] [Indexed: 01/21/2023]
Abstract
Microalgae can produce large quantities of triacylglycerols (TAGs) and other neutral lipids that are suitable for making biofuels and as feedstocks for green chemistry. However, TAGs accumulate under stress conditions that also stop growth, leading to a trade-off between biomass production and TAG yield. Recently, in the model marine diatom Phaeodactylum tricornutum it was shown that inhibition of the target of rapamycin (TOR) kinase boosts lipid productivity by promoting TAG production without stopping growth. We believe that basic knowledge in this emerging field is required to develop innovative strategies to improve neutral lipid accumulation in oleaginous microalgae. In this minireview, we discuss current research on the TOR signaling pathway with a focus on its control on lipid homeostasis. We first provide an overview of the well characterized roles of TOR in mammalian lipogenesis, adipogenesis and lipolysis. We then present evidence of a role for TOR in controlling TAG accumulation in microalgae, and draw parallels between the situation in animals, plants and microalgae to propose a model of TOR signaling for TAG accumulation in microalgae.
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Affiliation(s)
- Laura Prioretti
- Aix Marseille Univ, CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, 13402, Marseille, Cedex 09, France
| | - Frédéric Carriere
- Aix Marseille Univ, CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, 13402, Marseille, Cedex 09, France
| | - Ben Field
- Aix Marseille Univ, CEA, CNRS, UMR 7265 BIAM, 163 Avenue de Luminy, 13288, Marseille, France
| | - Luisana Avilan
- Aix Marseille Univ, CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, 13402, Marseille, Cedex 09, France
| | - Marie-Hélène Montané
- Aix Marseille Univ, CEA, CNRS, UMR 7265 BIAM, 163 Avenue de Luminy, 13288, Marseille, France
| | - Benoît Menand
- Aix Marseille Univ, CEA, CNRS, UMR 7265 BIAM, 163 Avenue de Luminy, 13288, Marseille, France.
| | - Brigitte Gontero
- Aix Marseille Univ, CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, 13402, Marseille, Cedex 09, France.
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Saucedo S, González A, Gómez M, Contreras RA, Laporte D, Sáez CA, Zúñiga G, Moenne A. Oligo-carrageenan kappa increases glucose, trehalose and TOR-P and subsequently stimulates the expression of genes involved in photosynthesis, and basal and secondary metabolisms in Eucalyptus globulus. BMC PLANT BIOLOGY 2019; 19:258. [PMID: 31208344 PMCID: PMC6580502 DOI: 10.1186/s12870-019-1858-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 05/30/2019] [Indexed: 05/14/2023]
Abstract
BACKGROUND It has been previously shown that oligo-carrageenan (OC) kappa increases growth, photosynthesis and activities of enzymes involved in basal and secondary metabolisms in Eucalyptus globulus. However, it is not known whether OC kappa may induce the activation of TOR pathway and the increase in expression of genes encoding proteins involved in photosynthesis and enzymes of basal and secondary metabolisms. RESULTS E. globulus trees were sprayed on leaves with water (control) or with OC kappa 1 mg mL- 1, once a week, four times in total, and cultivated for 17 additional weeks (21 weeks in total). Treated trees showed a higher level of net photosynthesis than controls, beginning at week 3, a higher height, beginning at week 9, and those differences remained until week 21. In addition, treated trees showed an increase in the level of glucose beginning at week 1, trehalose at weeks 1-3, and in TOR-P level at week 1-2. On the other hand, transcripts encoding proteins involved in photosynthesis, and enzymes involved in glucose accumulation, C, N and S assimilation, and synthesis of secondary metabolites began at weeks 3-4 and with additional peaks at weeks 5-6, 8-11,13-14 and 17-19. Thus, OC kappa induced initial increases in glucose, trehalose and TOR-P levels that were followed by oscillatory increases in the level of transcripts coding for proteins involved in photosynthesis, and in basal and secondary metabolisms suggesting that initial increases in glucose, trehalose and TOR-P may trigger activation of gene expression. CONCLUSIONS The stimulation of growth induced by OC kappa in E. globulus trees is due, at least in part, to activation of TOR pathway and the increase in expression of genes encoding proteins involved in photosynthesis and enzymes of basal metabolism.
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Affiliation(s)
- Silvia Saucedo
- Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
- Facultad de Ciencias Agrarias, Universidad Técnica Estatal de Quevedo, 63 Quevedo, Ecuador
| | - Alberto González
- Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
| | - Melissa Gómez
- Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
| | - Rodrigo A. Contreras
- Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
| | - Daniel Laporte
- Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
| | - Claudio A. Sáez
- Laboratory of Coastal Environmental Research, Center of Advanced Studies, University of Playa Ancha, Viña del Mar, Chile
| | - Gustavo Zúñiga
- Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
| | - Alejandra Moenne
- Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago, Chile
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Montané MH, Menand B. TOR inhibitors: from mammalian outcomes to pharmacogenetics in plants and algae. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2297-2312. [PMID: 30773593 DOI: 10.1093/jxb/erz053] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/05/2019] [Indexed: 05/19/2023]
Abstract
Target of rapamycin (TOR) is a conserved eukaryotic phosphatidylinositol 3-kinase-related kinase that regulates growth and metabolism in response to environment in plants and algae. The study of the plant and algal TOR pathway has largely depended on TOR inhibitors first developed for non-photosynthetic eukaryotes. In animals and yeast, fundamental work on the TOR pathway has benefited from the allosteric TOR inhibitor rapamycin and more recently from ATP-competitive TOR inhibitors (asTORis) that circumvent the limitations of rapamycin. The asTORis, developed for medical application, inhibit TOR complex 1 (TORC1) more efficiently than rapamycin and also inhibit rapamycin-resistant TORCs. This review presents knowledge on TOR inhibitors from the mammalian field and underlines important considerations for plant and algal biologists. It discusses the use of rapamycin and asTORis in plants and algae and concludes with guidelines for physiological studies and genetic screens with TOR inhibitors.
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Affiliation(s)
- Marie-Hélène Montané
- Aix Marseille Université, CEA, CNRS, BIAM, Laboratoire de génétique et biophysique des plantes, Marseille, F-13009, France
| | - Benoît Menand
- Aix Marseille Université, CEA, CNRS, BIAM, Laboratoire de génétique et biophysique des plantes, Marseille, F-13009, France
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Jamsheer K M, Jindal S, Laxmi A. Evolution of TOR-SnRK dynamics in green plants and its integration with phytohormone signaling networks. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2239-2259. [PMID: 30870564 DOI: 10.1093/jxb/erz107] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/26/2019] [Indexed: 05/07/2023]
Abstract
The target of rapamycin (TOR)-sucrose non-fermenting 1 (SNF1)-related protein kinase 1 (SnRK1) signaling is an ancient regulatory mechanism that originated in eukaryotes to regulate nutrient-dependent growth. Although the TOR-SnRK1 signaling cascade shows highly conserved functions among eukaryotes, studies in the past two decades have identified many important plant-specific innovations in this pathway. Plants also possess SnRK2 and SnRK3 kinases, which originated from the ancient SnRK1-related kinases and have specialized roles in controlling growth, stress responses and nutrient homeostasis in plants. Recently, an integrative picture has started to emerge in which different SnRKs and TOR kinase are highly interconnected to control nutrient and stress responses of plants. Further, these kinases are intimately involved with phytohormone signaling networks that originated at different stages of plant evolution. In this review, we highlight the evolution and divergence of TOR-SnRK signaling components in plants and their communication with each other as well as phytohormone signaling to fine-tune growth and stress responses in plants.
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Affiliation(s)
- Muhammed Jamsheer K
- Amity Food & Agriculture Foundation, Amity University Uttar Pradesh, Noida, India
| | - Sunita Jindal
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Ashverya Laxmi
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
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Bakshi A, Moin M, Madhav MS, Kirti PB. Target of rapamycin, a master regulator of multiple signalling pathways and a potential candidate gene for crop improvement. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:190-205. [PMID: 30411830 DOI: 10.1111/plb.12935] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/05/2018] [Indexed: 06/08/2023]
Abstract
The target of rapamycin (TOR) protein regulates growth and development in photosynthetic and non-photosynthetic eukaryotes. Although the TOR regulatory networks are involved in nutrient and energy signalling, and transcriptional and translational control of multiple signalling pathways, the molecular mechanism of TOR regulation of plant abiotic stress responses is still unclear. The TOR-mediated transcriptional regulation of genes encoding ribosomal proteins (RP) is a necessity under stress conditions for balanced growth and productivity in plants. The activation of SnRKs (sucrose non-fermenting-related kinases) and the inactivation of TOR signalling in abiotic stresses is in line with the accumulation of ABA and transcriptional activation of stress responsive genes. Autophagy is induced under abiotic stress conditions, which results in degradation of proteins and the release of amino acids, which might possibly induce phosphorylation of TOR and, hence, its activation. TOR signalling also has a role in regulating ABA biosynthesis for transcriptional regulation of stress-related genes. The switch between activation and inactivation of TOR by its phosphorylation and de-phosphorylation maintains balanced growth in response to stresses. In the present review, we discuss the important signalling pathways that are regulated by TOR and try to assess the relationship between TOR signalling and tolerance to abiotic stresses in plants. The review also discusses possible cross-talk between TOR and RP genes in response to abiotic stresses.
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Affiliation(s)
- A Bakshi
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
| | - M Moin
- Department of Biotechnology, Indian Institute of Rice Research, Hyderabad, India
| | - M S Madhav
- Department of Biotechnology, Indian Institute of Rice Research, Hyderabad, India
| | - P B Kirti
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
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Werth EG, McConnell EW, Couso Lianez I, Perrine Z, Crespo JL, Umen JG, Hicks LM. Investigating the effect of target of rapamycin kinase inhibition on the Chlamydomonas reinhardtii phosphoproteome: from known homologs to new targets. THE NEW PHYTOLOGIST 2019; 221:247-260. [PMID: 30040123 DOI: 10.1111/nph.15339] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/11/2018] [Indexed: 05/20/2023]
Abstract
Target of rapamycin (TOR) kinase is a conserved regulator of cell growth whose activity is modulated in response to nutrients, energy and stress. Key proteins involved in the pathway are conserved in the model photosynthetic microalga Chlamydomonas reinhardtii, but the substrates of TOR kinase and downstream signaling network have not been elucidated. Our study provides a new resource for investigating the phosphorylation networks governed by the TOR kinase pathway in Chlamydomonas. We used quantitative phosphoproteomics to investigate the effects of inhibiting Chlamydomonas TOR kinase on dynamic protein phosphorylation. Wild-type and AZD-insensitive Chlamydomonas strains were treated with TOR-specific chemical inhibitors (rapamycin, AZD8055 and Torin1), after which differentially affected phosphosites were identified. Our quantitative phosphoproteomic dataset comprised 2547 unique phosphosites from 1432 different proteins. Inhibition of TOR kinase caused significant quantitative changes in phosphorylation at 258 phosphosites, from 219 unique phosphopeptides. Our results include Chlamydomonas homologs of TOR signaling-related proteins, including a site on RPS6 with a decrease in phosphorylation. Additionally, phosphosites on proteins involved in translation and carotenoid biosynthesis were identified. Follow-up experiments guided by these phosphoproteomic findings in lycopene beta/epsilon cyclase showed that carotenoid levels are affected by TORC1 inhibition and carotenoid production is under TOR control in algae.
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Affiliation(s)
- Emily G Werth
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Evan W McConnell
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Inmaculada Couso Lianez
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Avda. Américo Vespucio 49, 41092, Sevilla, Spain
| | - Zoee Perrine
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - Jose L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Avda. Américo Vespucio 49, 41092, Sevilla, Spain
| | - James G Umen
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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Takeuchi T, Benning C. Nitrogen-dependent coordination of cell cycle, quiescence and TAG accumulation in Chlamydomonas. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:292. [PMID: 31890020 PMCID: PMC6927116 DOI: 10.1186/s13068-019-1635-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 12/12/2019] [Indexed: 05/07/2023]
Abstract
Microalgae hold great promises as sustainable cellular factories for the production of alternative fuels, feeds, and biopharmaceuticals for human health. While the biorefinery approach for fuels along with the coproduction of high-value compounds with industrial, therapeutic, or nutraceutical applications have the potential to make algal biofuels more economically viable, a number of challenges continue to hamper algal production systems at all levels. One such hurdle includes the metabolic trade-off often observed between the increased yields of desired products, such as triacylglycerols (TAG), and the growth of an organism. Initial genetic engineering strategies to improve lipid productivity in microalgae, which focused on overproducing the enzymes involved in fatty acid and TAG biosynthesis or inactivating competing carbon (C) metabolism, have seen some successes albeit at the cost of often greatly reduced biomass. Emergent approaches that aim at modifying the dynamics of entire metabolic pathways by engineering of pertinent transcription factors or signaling networks appear to have successfully achieved a balance between growth and neutral lipid accumulation. However, the biological knowledge of key signaling networks and molecular components linking these two processes is still incomplete in photosynthetic eukaryotes, making it difficult to optimize metabolic engineering strategies for microalgae. Here, we focus on nitrogen (N) starvation of the model green microalga, Chlamydomonas reinhardtii, to present the current understanding of the nutrient-dependent switch between proliferation and quiescence, and the drastic reprogramming of metabolism that results in the storage of C compounds following N starvation. We discuss the potential components mediating the transcriptional repression of cell cycle genes and the establishment of quiescence in Chlamydomonas, and highlight the importance of signaling pathways such as those governed by the target of rapamycin (TOR) and sucrose nonfermenting-related (SnRK) kinases in the coordination of metabolic status with cellular growth. A better understanding of how the cell division cycle is regulated in response to nutrient scarcity and of the signaling pathways linking cellular growth to energy and lipid homeostasis, is essential to improve the prospects of biofuels and biomass production in microalgae.
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Affiliation(s)
- Tomomi Takeuchi
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 USA
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
| | - Christoph Benning
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 USA
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824 USA
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Heredia-Martínez LG, Andrés-Garrido A, Martínez-Force E, Pérez-Pérez ME, Crespo JL. Chloroplast Damage Induced by the Inhibition of Fatty Acid Synthesis Triggers Autophagy in Chlamydomonas. PLANT PHYSIOLOGY 2018; 178:1112-1129. [PMID: 30181343 PMCID: PMC6236622 DOI: 10.1104/pp.18.00630] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/23/2018] [Indexed: 05/19/2023]
Abstract
Fatty acids are synthesized in the stroma of plant and algal chloroplasts by the fatty acid synthase complex. Newly synthesized fatty acids are then used to generate plastidial lipids that are essential for chloroplast structure and function. Here, we show that inhibition of fatty acid synthesis in the model alga Chlamydomonas reinhardtii activates autophagy, a highly conserved catabolic process by which cells degrade intracellular material under adverse conditions to maintain cell homeostasis. Treatment of Chlamydomonas cells with cerulenin, a specific fatty acid synthase inhibitor, stimulated lipidation of the autophagosome protein ATG8 and enhanced autophagic flux. We found that inhibition of fatty acid synthesis decreased monogalactosyldiacylglycerol abundance, increased lutein content, down-regulated photosynthesis, and increased the production of reactive oxygen species. Electron microscopy revealed a high degree of thylakoid membrane stacking in cerulenin-treated cells. Moreover, global transcriptomic analysis of these cells showed an up-regulation of genes encoding chloroplast proteins involved in protein folding and oxidative stress and the induction of major catabolic processes, including autophagy and proteasome pathways. Thus, our results uncovered a link between lipid metabolism, chloroplast integrity, and autophagy through a mechanism that involves the activation of a chloroplast quality control system.
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Affiliation(s)
- Luis Gonzaga Heredia-Martínez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092 Seville, Spain
| | - Ascensión Andrés-Garrido
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092 Seville, Spain
| | - Enrique Martínez-Force
- Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, 41013 Seville, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092 Seville, Spain
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092 Seville, Spain
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Mubeen U, Jüppner J, Alpers J, Hincha DK, Giavalisco P. Target of Rapamycin Inhibition in Chlamydomonas reinhardtii Triggers de Novo Amino Acid Synthesis by Enhancing Nitrogen Assimilation. THE PLANT CELL 2018; 30:2240-2254. [PMID: 30228127 PMCID: PMC6241278 DOI: 10.1105/tpc.18.00159] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 07/30/2018] [Accepted: 09/13/2018] [Indexed: 05/19/2023]
Abstract
The Target of Rapamycin (TOR) kinase is a central regulator of growth and metabolism in all eukaryotic organisms, including animals, fungi, and plants. Even though the inputs and outputs of TOR signaling are well characterized for animals and fungi, our understanding of the upstream regulators of TOR and its downstream targets is still fragmentary in photosynthetic organisms. In this study, we employed the rapamycin-sensitive green alga Chlamydomonas reinhardtii to elucidate the molecular cause of the amino acid accumulation that occurs after rapamycin-induced inhibition of TOR. Using different growth conditions and stable 13C- and 15N-isotope labeling, we show that this phenotype is accompanied by increased nitrogen (N) uptake, which is induced within minutes of TOR inhibition. Interestingly, this increased N influx is accompanied by increased activities of glutamine synthetase and glutamine oxoglutarate aminotransferase, the main N-assimilating enzymes, which are responsible for the rise in levels of several amino acids, which occurs within a few minutes. Accordingly, we conclude that even though translation initiation and autophagy have been reported to be the main downstream targets of TOR, the upregulation of de novo amino acid synthesis seems to be one of the earliest responses induced after the inhibition of TOR in Chlamydomonas.
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Affiliation(s)
- Umarah Mubeen
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Jessica Jüppner
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Jessica Alpers
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Dirk K Hincha
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Patrick Giavalisco
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
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40
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Dong Q, Mao K, Duan D, Zhao S, Wang Y, Wang Q, Huang D, Li C, Liu C, Gong X, Ma F. Genome-wide analyses of genes encoding FK506-binding proteins reveal their involvement in abiotic stress responses in apple. BMC Genomics 2018; 19:707. [PMID: 30253753 PMCID: PMC6156878 DOI: 10.1186/s12864-018-5097-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 09/20/2018] [Indexed: 12/30/2022] Open
Abstract
Background The FK506-binding proteins (FKBPs) play diverse roles in numerous critical processes for plant growth, development, and abiotic stress responses. However, the FKBP gene family in the important fruit crop apple (Malus × domestica Borkh.) has not been studied as thoroughly as in other species. Our research objective was to investigate the mechanisms by which apple FKBPs enable apple plants to tolerate the effects of abiotic stresses. Results Using bioinformatics-based methods, RT-PCR, and qRT-PCR technologies, we identified 38 FKBP genes and cloned 16 of them in the apple genome. The phylogenetic analysis revealed three major groups within that family. The results from sequence alignments, 3-D structures, phylogenetics, and analyses of conserved domains indicated that apple FKBPs are highly and structurally conserved. Furthermore, genomics structure analysis showed that those genes are also highly and structurally conserved in several other species. Comprehensive qRT-PCR analysis found various expression patterns for MdFKBPs in different tissues and in plant responses to water-deficit and salt stresses. Based on the results from interaction network and co-expression analyses, we determined that the pairing in the MdFKBP62a/MdFKBP65a/b-mediated network is involved in water-deficit and salt-stress signaling, both of which are uniformly up-regulated through interactions with heat shock proteins in apple. Conclusions These results provide new insight for further study of FKBP genes and their functions in abiotic stress response and multiple metabolic and physiological processes in apple. Electronic supplementary material The online version of this article (10.1186/s12864-018-5097-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Qinglong Dong
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Ke Mao
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Dingyue Duan
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Shuang Zhao
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Yanpeng Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Qian Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Dong Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Chao Li
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Changhai Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Xiaoqing Gong
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Fengwang Ma
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China.
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Crozet P, Navarro FJ, Willmund F, Mehrshahi P, Bakowski K, Lauersen KJ, Pérez-Pérez ME, Auroy P, Gorchs Rovira A, Sauret-Gueto S, Niemeyer J, Spaniol B, Theis J, Trösch R, Westrich LD, Vavitsas K, Baier T, Hübner W, de Carpentier F, Cassarini M, Danon A, Henri J, Marchand CH, de Mia M, Sarkissian K, Baulcombe DC, Peltier G, Crespo JL, Kruse O, Jensen PE, Schroda M, Smith AG, Lemaire SD. Birth of a Photosynthetic Chassis: A MoClo Toolkit Enabling Synthetic Biology in the Microalga Chlamydomonas reinhardtii. ACS Synth Biol 2018; 7:2074-2086. [PMID: 30165733 DOI: 10.1021/acssynbio.8b00251] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microalgae are regarded as promising organisms to develop innovative concepts based on their photosynthetic capacity that offers more sustainable production than heterotrophic hosts. However, to realize their potential as green cell factories, a major challenge is to make microalgae easier to engineer. A promising approach for rapid and predictable genetic manipulation is to use standardized synthetic biology tools and workflows. To this end we have developed a Modular Cloning toolkit for the green microalga Chlamydomonas reinhardtii. It is based on Golden Gate cloning with standard syntax, and comprises 119 openly distributed genetic parts, most of which have been functionally validated in several strains. It contains promoters, UTRs, terminators, tags, reporters, antibiotic resistance genes, and introns cloned in various positions to allow maximum modularity. The toolkit enables rapid building of engineered cells for both fundamental research and algal biotechnology. This work will make Chlamydomonas the next chassis for sustainable synthetic biology.
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Affiliation(s)
- Pierre Crozet
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | | | - Felix Willmund
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Payam Mehrshahi
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Kamil Bakowski
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kyle J. Lauersen
- Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, 33615, Germany
| | - Maria-Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, 41092, Spain
| | - Pascaline Auroy
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues Cadarache, Aix Marseille University, CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
| | - Aleix Gorchs Rovira
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Susana Sauret-Gueto
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Justus Niemeyer
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Benjamin Spaniol
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Jasmine Theis
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Raphael Trösch
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Lisa-Desiree Westrich
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Konstantinos Vavitsas
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Baier
- Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, 33615, Germany
| | - Wolfgang Hübner
- Biomolecular Photonics, Department of Physics, Bielefeld University, Bielefeld, 33615, Germany
| | - Felix de Carpentier
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Mathieu Cassarini
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Antoine Danon
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Julien Henri
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Christophe H. Marchand
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Marcello de Mia
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Kevin Sarkissian
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - David C. Baulcombe
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Gilles Peltier
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues Cadarache, Aix Marseille University, CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
| | - José-Luis Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, 41092, Spain
| | - Olaf Kruse
- Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, 33615, Germany
| | - Poul-Erik Jensen
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Schroda
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Alison G. Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Stéphane D. Lemaire
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
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Ramanan R, Tran QG, Cho DH, Jung JE, Kim BH, Shin SY, Choi SH, Liu KH, Kim DS, Lee SJ, Crespo JL, Lee HG, Oh HM, Kim HS. The Ancient Phosphatidylinositol 3-Kinase Signaling System Is a Master Regulator of Energy and Carbon Metabolism in Algae. PLANT PHYSIOLOGY 2018; 177:1050-1065. [PMID: 29769325 PMCID: PMC6053016 DOI: 10.1104/pp.17.01780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/02/2018] [Indexed: 05/08/2023]
Abstract
Algae undergo a complete metabolic transformation under stress by arresting cell growth, inducing autophagy and hyper-accumulating biofuel precursors such as triacylglycerols and starch. However, the regulatory mechanisms behind this stress-induced transformation are still unclear. Here, we use biochemical, mutational, and "omics" approaches to demonstrate that PI3K signaling mediates the homeostasis of energy molecules and influences carbon metabolism in algae. In Chlamydomonas reinhardtii, the inhibition and knockdown (KD) of algal class III PI3K led to significantly decreased cell growth, altered cell morphology, and higher lipid and starch contents. Lipid profiling of wild-type and PI3K KD lines showed significantly reduced membrane lipid breakdown under nitrogen starvation (-N) in the KD. RNA-seq and network analyses showed that under -N conditions, the KD line carried out lipogenesis rather than lipid hydrolysis by initiating de novo fatty acid biosynthesis, which was supported by tricarboxylic acid cycle down-regulation and via acetyl-CoA synthesis from glycolysis. Remarkably, autophagic responses did not have primacy over inositide signaling in algae, unlike in mammals and vascular plants. The mutant displayed a fundamental shift in intracellular energy flux, analogous to that in tumor cells. The high free fatty acid levels and reduced mitochondrial ATP generation led to decreased cell viability. These results indicate that the PI3K signal transduction pathway is the metabolic gatekeeper restraining biofuel yields, thus maintaining fitness and viability under stress in algae. This study demonstrates the existence of homeostasis between starch and lipid synthesis controlled by lipid signaling in algae and expands our understanding of such processes, with biotechnological and evolutionary implications.
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Affiliation(s)
- Rishiram Ramanan
- Department of Environmental Science, School of Earth Science Systems, Central University of Kerala, Tejaswini Hills, Periya, Kasaragod 671316, Kerala, India
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Quynh-Giao Tran
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Daejeon 34141, Republic of Korea
- Department of Environmental Biotechnology, KRIBB School of Biotechnology, Korea University of Science and Technology, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Dae-Hyun Cho
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jae-Eun Jung
- Genome Research Center, KRIBB, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Byung-Hyuk Kim
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sang-Yoon Shin
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Daejeon 34141, Republic of Korea
- Department of Environmental Biotechnology, KRIBB School of Biotechnology, Korea University of Science and Technology, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sae-Hae Choi
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Kwang-Hyeon Liu
- College of Pharmacy, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Dae-Soo Kim
- Genome Research Center, KRIBB, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Seon-Jin Lee
- Biomedical Genomics Research Center, KRIBB, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - José L Crespo
- Instituto de Bioquimica Vegetal y Fotosintesis, Consejo Superior de Investigaciones Cientificas, Universidad de Sevilla, Seville 41092, Spain
| | - Hee-Gu Lee
- Biomedical Genomics Research Center, KRIBB, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hee-Mock Oh
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Daejeon 34141, Republic of Korea
- Department of Environmental Biotechnology, KRIBB School of Biotechnology, Korea University of Science and Technology, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hee-Sik Kim
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Daejeon 34141, Republic of Korea
- Department of Environmental Biotechnology, KRIBB School of Biotechnology, Korea University of Science and Technology, Yuseong-gu, Daejeon 34141, Republic of Korea
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43
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Abstract
Plants have evolved sophisticated mechanisms to recycle intracellular constituents, which are essential for developmental and metabolic transitions; for efficient nutrient reuse; and for the proper disposal of proteins, protein complexes, and even entire organelles that become obsolete or dysfunctional. One major route is autophagy, which employs specialized vesicles to encapsulate and deliver cytoplasmic material to the vacuole for breakdown. In the past decade, the mechanics of autophagy and the scores of components involved in autophagic vesicle assembly have been documented. Now emerging is the importance of dedicated receptors that help recruit appropriate cargo, which in many cases exploit ubiquitylation as a signal. Although operating at a low constitutive level in all plant cells, autophagy is upregulated during senescence and various environmental challenges and is essential for proper nutrient allocation. Its importance to plant metabolism and energy balance in particular places autophagy at the nexus of robust crop performance, especially under suboptimal conditions.
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Affiliation(s)
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, USA;
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44
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Couso I, Pérez-Pérez ME, Martínez-Force E, Kim HS, He Y, Umen JG, Crespo JL. Autophagic flux is required for the synthesis of triacylglycerols and ribosomal protein turnover in Chlamydomonas. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1355-1367. [PMID: 29053817 PMCID: PMC6018900 DOI: 10.1093/jxb/erx372] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 09/28/2017] [Indexed: 05/19/2023]
Abstract
Autophagy is an intracellular catabolic process that allows cells to recycle unneeded or damaged material to maintain cellular homeostasis. This highly dynamic process is characterized by the formation of double-membrane vesicles called autophagosomes, which engulf and deliver the cargo to the vacuole. Flow of material through the autophagy pathway and its degradation in the vacuole is known as autophagic flux, and reflects the autophagic degradation activity. A number of assays have been developed to determine autophagic flux in yeasts, mammals, and plants, but it has not been examined yet in algae. Here we analyzed autophagic flux in the model green alga Chlamydomonas reinhardtii. By monitoring specific autophagy markers such as ATG8 lipidation and using immunofluorescence and electron microscopy techniques, we show that concanamycin A, a vacuolar ATPase inhibitor, blocks autophagic flux in Chlamydomonas. Our results revealed that vacuolar lytic function is needed for the synthesis of triacylglycerols and the formation of lipid bodies in nitrogen- or phosphate-starved cells. Moreover, we found that concanamycin A treatment prevented the degradation of ribosomal proteins RPS6 and RPL37 under nitrogen or phosphate deprivation. These results indicate that autophagy might play an important role in the regulation of lipid metabolism and the recycling of ribosomal proteins under nutrient limitation in Chlamydomonas.
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Affiliation(s)
- Inmaculada Couso
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Seville, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Seville, Spain
| | - Enrique Martínez-Force
- Instituto de la Grasa (CSIC), Edificio 46, Campus Universitario Pablo de Olavide, Seville, Spain
| | - Hee-Sik Kim
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Yonghua He
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - James G Umen
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Seville, Spain
- Correspondence:
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45
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Avin-Wittenberg T, Baluška F, Bozhkov PV, Elander PH, Fernie AR, Galili G, Hassan A, Hofius D, Isono E, Le Bars R, Masclaux-Daubresse C, Minina EA, Peled-Zehavi H, Coll NS, Sandalio LM, Satiat-Jeunemaitre B, Sirko A, Testillano PS, Batoko H. Autophagy-related approaches for improving nutrient use efficiency and crop yield protection. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1335-1353. [PMID: 29474677 DOI: 10.1093/jxb/ery069] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/16/2018] [Indexed: 05/18/2023]
Abstract
Autophagy is a eukaryotic catabolic pathway essential for growth and development. In plants, it is activated in response to environmental cues or developmental stimuli. However, in contrast to other eukaryotic systems, we know relatively little regarding the molecular players involved in autophagy and the regulation of this complex pathway. In the framework of the COST (European Cooperation in Science and Technology) action TRANSAUTOPHAGY (2016-2020), we decided to review our current knowledge of autophagy responses in higher plants, with emphasis on knowledge gaps. We also assess here the potential of translating the acquired knowledge to improve crop plant growth and development in a context of growing social and environmental challenges for agriculture in the near future.
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Affiliation(s)
- Tamar Avin-Wittenberg
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Frantisek Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Pernilla H Elander
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - Gad Galili
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot Israel
| | - Ammar Hassan
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Daniel Hofius
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, Uppsala, Sweden
| | - Erika Isono
- Department of Biology, University of Konstanz, Universitätsstrasse, Konstanz, Germany
| | - Romain Le Bars
- Cell Biology Pôle Imagerie-Gif, Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Céline Masclaux-Daubresse
- INRA-AgroParisTech, Institut Jean-Pierre Bourgin, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, Versailles, France
| | - Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Hadas Peled-Zehavi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot Israel
| | - Núria S Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra-Cerdanyola del Valles, Catalonia, Spain
| | - Luisa M Sandalio
- Departmento de Bioquímica, Biología Celular y Molecular de Plantas Experimental del Zaidín, CSIC, Granada, Spain
| | - Béatrice Satiat-Jeunemaitre
- Cell Biology Pôle Imagerie-Gif, Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Agnieszka Sirko
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, ul. Pawinskiego, Warsaw, Poland
| | - Pilar S Testillano
- Pollen Biotechnology of Crop Plants group, Centro de Investigaciones Biológicas, Biological Research Centre (CIB), CSIC, Ramiro de Maeztu, Madrid, Spain
| | - Henri Batoko
- Université Catholique de Louvain, Institute of Life Sciences, Croix du Sud, Louvain-la-Neuve, Belgium
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46
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Alavilli H, Lee H, Park M, Yun DJ, Lee BH. Enhanced multiple stress tolerance in Arabidopsis by overexpression of the polar moss peptidyl prolyl isomerase FKBP12 gene. PLANT CELL REPORTS 2018; 37:453-465. [PMID: 29247292 DOI: 10.1007/s00299-017-2242-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 12/05/2017] [Indexed: 06/07/2023]
Abstract
PaFKBP12 overexpression in Arabidopsis resulted in stress tolerance to heat, ABA, drought, and salt stress, in addition to growth promotion under normal conditions. Polytrichastrum alpinum (alpine haircap moss) is one of polar organisms that can withstand the severe conditions of the Antarctic. In this study, we report the isolation of a peptidyl prolyl isomerase FKBP12 gene (PaFKBP12) from P. alpinum collected in the Antarctic and its functional implications in development and stress responses in plants. In P. alpinum, PaFKBP12 expression was induced by heat and ABA. Overexpression of PaFKBP12 in Arabidopsis increased the plant size, which appeared to result from increased rates of cell cycle. Under heat stress conditions, PaFKBP12-overexpressing lines (PaFKBP12-OE) showed better growth and survival than the wild type. PaFKBP12-OE also showed higher root elongation rates, better shoot growth and enhanced survival at higher concentrations of ABA in comparison to the wild type. In addition, PaFKBP12-OE were more tolerant to drought and salt stress than the wild type. All these phenotypes were accompanied with higher induction of the stress responsive genes in PaFKBP12-OE than in the wild type. Taken together, our findings revealed important functions of PaFKBP12 in plant development and abiotic stress responses.
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Affiliation(s)
| | - Hyoungseok Lee
- Unit of Polar Genomics, Korea Polar Research Institute, Incheon, 21990, South Korea
| | - Mira Park
- Department of Life Science, Sogang University, Seoul, 04107, South Korea
- Unit of Polar Genomics, Korea Polar Research Institute, Incheon, 21990, South Korea
| | - Dae-Jin Yun
- Department of Biomedical Science and Engineering, Konkuk University, Seoul, 05029, South Korea
| | - Byeong-Ha Lee
- Department of Life Science, Sogang University, Seoul, 04107, South Korea.
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47
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Jüppner J, Mubeen U, Leisse A, Caldana C, Wiszniewski A, Steinhauser D, Giavalisco P. The target of rapamycin kinase affects biomass accumulation and cell cycle progression by altering carbon/nitrogen balance in synchronized Chlamydomonas reinhardtii cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:355-376. [PMID: 29172247 DOI: 10.1111/tpj.13787] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/31/2017] [Accepted: 11/15/2017] [Indexed: 05/19/2023]
Abstract
Several metabolic processes tightly regulate growth and biomass accumulation. A highly conserved protein complex containing the target of rapamycin (TOR) kinase is known to integrate intra- and extracellular stimuli controlling nutrient allocation and hence cellular growth. Although several functions of TOR have been described in various heterotrophic eukaryotes, our understanding lags far behind in photosynthetic organisms. In the present investigation, we used the model alga Chlamydomonas reinhardtii to conduct a time-resolved analysis of molecular and physiological features throughout the diurnal cycle after TOR inhibition. Detailed examination of the cell cycle phases revealed that growth is not only repressed by 50%, but also that significant, non-linear delays in the progression can be observed. By using metabolomics analysis, we elucidated that the growth repression was mainly driven by differential carbon partitioning between anabolic and catabolic processes. Accordingly, the time-resolved analysis illustrated that metabolic processes including amino acid-, starch- and triacylglycerol synthesis, as well RNA degradation, were redirected within minutes of TOR inhibition. Here especially the high accumulation of nitrogen-containing compounds indicated that an active TOR kinase controls the carbon to nitrogen balance of the cell, which is responsible for biomass accumulation, growth and cell cycle progression.
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Affiliation(s)
- Jessica Jüppner
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Umarah Mubeen
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Andrea Leisse
- 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
- Brazilian Bioethanol Science and Technology Laboratory/CNPEM, Rua Giuseppe Máximo Scolfano 10000, 13083-970, Campinas, Brazil
| | - Andrew Wiszniewski
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Dirk Steinhauser
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Patrick Giavalisco
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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48
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Roustan V, Weckwerth W. Quantitative Phosphoproteomic and System-Level Analysis of TOR Inhibition Unravel Distinct Organellar Acclimation in Chlamydomonas reinhardtii. FRONTIERS IN PLANT SCIENCE 2018; 9:1590. [PMID: 30546371 PMCID: PMC6280106 DOI: 10.3389/fpls.2018.01590] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 10/15/2018] [Indexed: 05/13/2023]
Abstract
Rapamycin is an inhibitor of the evolutionary conserved Target of Rapamycin (TOR) kinase which promotes and coordinates translation with cell growth and division. In heterotrophic organisms, TOR regulation is based on intra- and extracellular stimuli such as amino acids level and insulin perception. However, how plant TOR pathways have evolved to integrate plastid endosymbiosis is a remaining question. Despite the close association of the TOR signaling with the coordination between protein turn-over and growth, proteome and phosphoproteome acclimation to a rapamycin treatment have not yet been thoroughly investigated in Chlamydomonas reinhardtii. In this study, we have used in vivo label-free phospho-proteomic analysis to profile both protein and phosphorylation changes at 0, 24, and 48 h in Chlamydomonas cells treated with rapamycin. Using multivariate statistics we highlight the impact of TOR inhibition on both the proteome and the phosphoproteome. Two-way ANOVA distinguished differential levels of proteins and phosphoproteins in response either to culture duration and rapamycin treatment or combined effects. Finally, protein-protein interaction networks and functional enrichment analysis underlined the relation between plastid and mitochondrial metabolism. Prominent changes of proteins involved in sulfur, cysteine, and methionine as well as nucleotide metabolism on the one hand, and changes in the TCA cycle on the other highlight the interplay of chloroplast and mitochondria metabolism. Furthermore, TOR inhibition revealed changes in the endomembrane trafficking system. Phosphoproteomics data, on the other hand, highlighted specific differentially regulated phosphorylation sites for calcium-regulated protein kinases as well as ATG7, S6K, and PP2C. To conclude we provide a first combined Chlamydomonas proteomics and phosphoproteomics dataset in response to TOR inhibition, which will support further investigations.
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Affiliation(s)
- Valentin Roustan
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Wolfram Weckwerth
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
- Vienna Metabolomics Center (VIME), University of Vienna, Vienna, Austria
- *Correspondence: Wolfram Weckwerth,
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49
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Efficient targeted DNA editing and replacement in Chlamydomonas reinhardtii using Cpf1 ribonucleoproteins and single-stranded DNA. Proc Natl Acad Sci U S A 2017; 114:13567-13572. [PMID: 29208717 DOI: 10.1073/pnas.1710597114] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The green alga Chlamydomonas reinhardtii is an invaluable reference organism to research fields including algal, plant, and ciliary biology. Accordingly, decades-long standing inefficiencies in targeted nuclear gene editing broadly hinder Chlamydomonas research. Here we report that single-step codelivery of CRISPR/Cpf1 ribonucleoproteins with single-stranded DNA repair templates results in precise and targeted DNA replacement with as much as ∼10% efficiency in C. reinhardtii We demonstrate its use in transgene- and selection-free generation of sequence-specific mutations and epitope tagging at an endogenous locus. As the direct delivery of gene-editing reagents bypasses the use of transgenes, this method is potentially applicable to a wider range of species without the need to develop methods for stable transformation.
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50
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Monitoring Autophagy in the Model Green Microalga Chlamydomonas reinhardtii. Cells 2017; 6:cells6040036. [PMID: 29065500 PMCID: PMC5755495 DOI: 10.3390/cells6040036] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/17/2017] [Accepted: 10/19/2017] [Indexed: 01/19/2023] Open
Abstract
Autophagy is an intracellular catabolic system that delivers cytoplasmic constituents and organelles in the vacuole. This degradative process is mediated by a group of proteins coded by autophagy-related (ATG) genes that are widely conserved from yeasts to plants and mammals. Homologs of ATG genes have been also identified in algal genomes including the unicellular model green alga Chlamydomonas reinhardtii. The development of specific tools to monitor autophagy in Chlamydomonas has expanded our current knowledge about the regulation and function of this process in algae. Recent findings indicated that autophagy is regulated by redox signals and the TOR network in Chlamydomonas and revealed that this process may play in important role in the control of lipid metabolism and ribosomal protein turnover in this alga. Here, we will describe the different techniques and approaches that have been reported to study autophagy and autophagic flux in Chlamydomonas.
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