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Foresi N, De Marco MA, Del Castello F, Ramirez L, Nejamkin A, Calo G, Grimsley N, Correa-Aragunde N, Martínez-Noël GMA. The tiny giant of the sea, Ostreococcus's unique adaptations. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 211:108661. [PMID: 38735153 DOI: 10.1016/j.plaphy.2024.108661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 04/14/2024] [Accepted: 04/23/2024] [Indexed: 05/14/2024]
Abstract
Ostreococcus spp. are unicellular organisms with one of the simplest cellular organizations. The sequencing of the genomes of different Ostreococcus species has reinforced this status since Ostreococcus tauri has one most compact nuclear genomes among eukaryotic organisms. Despite this, it has retained a number of genes, setting it apart from other organisms with similar small genomes. Ostreococcus spp. feature a substantial number of selenocysteine-containing proteins, which, due to their higher catalytic activity compared to their selenium-lacking counterparts, may require a reduced quantity of proteins. Notably, O. tauri encodes several ammonium transporter genes, that may provide it with a competitive edge for acquiring nitrogen (N). This characteristic makes it an intriguing model for studying the efficient use of N in eukaryotes. Under conditions of low N availability, O. tauri utilizes N from abundant proteins or amino acids, such as L-arginine, similar to higher plants. However, the presence of a nitric oxide synthase (L-arg substrate) sheds light on a new metabolic pathway for L-arg in algae. The metabolic adaptations of O. tauri to day and night cycles offer valuable insights into carbon and iron metabolic configuration. O. tauri has evolved novel strategies to optimize iron uptake, lacking the classic components of the iron absorption mechanism. Overall, the cellular and genetic characteristics of Ostreococcus contribute to its evolutionary success, making it an excellent model for studying the physiological and genetic aspects of how green algae have adapted to the marine environment. Furthermore, given its potential for lipid accumulation and its marine habitat, it may represent a promising avenue for third-generation biofuels.
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Affiliation(s)
- Noelia Foresi
- Instituto de Investigaciones Biológicas-UNMdP-CONICET, Mar del Plata, Argentina.
| | - María Agustina De Marco
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC)-CONICET-FIBA, Mar del Plata, Argentina
| | | | - Leonor Ramirez
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, SE-901 87, Umeå, Sweden
| | - Andres Nejamkin
- Instituto de Investigaciones Biológicas-UNMdP-CONICET, Mar del Plata, Argentina
| | - Gonzalo Calo
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC)-CONICET-FIBA, Mar del Plata, Argentina
| | - Nigel Grimsley
- CNRS, LBBM, Sorbonne Université OOB, 1 Avenue de Pierre Fabre, 66650, Banyuls-sur-Mer, France
| | | | - Giselle M A Martínez-Noël
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC)-CONICET-FIBA, Mar del Plata, Argentina.
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Helliwell KE. Emerging trends in nitrogen and phosphorus signalling in photosynthetic eukaryotes. TRENDS IN PLANT SCIENCE 2023; 28:344-358. [PMID: 36372648 DOI: 10.1016/j.tplants.2022.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/12/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Phosphorus (P) and nitrogen (N) are the major nutrients that constrain plant and algal growth in nature. Recent advances in understanding nutrient signalling mechanisms of these organisms have revealed molecular attributes to optimise N and P acquisition. This has illuminated the importance of interplay between N and P regulatory networks, highlighting a need to study synergistic interactions rather than single-nutrient effects. Emerging insights of nutrient signalling in polyphyletic model plants and algae hint that, although core P-starvation signalling components are conserved, distinct mechanisms for P (and N) sensing have arisen. Here, the N and P signalling mechanisms of diverse photosynthetic eukaryotes are examined, drawing parallels and differences between taxa. Future directions to understand their molecular basis, evolution, and ecology are proposed.
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Affiliation(s)
- Katherine E Helliwell
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK; Marine Biological Association, Citadel Hill, Plymouth PL1 2PB, UK.
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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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Hou J, Li C, Cheng Y, Jiang C, Li Y, Ge Y, Li J. Roles of calcium-dependent protein kinases mediated reactive oxygen species homeostasis in inducing resistance of apples by acibenzolar-S-methyl. Food Chem 2021; 346:128881. [PMID: 33482531 DOI: 10.1016/j.foodchem.2020.128881] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 11/30/2020] [Accepted: 12/14/2020] [Indexed: 10/22/2022]
Abstract
This study was carried out to investigate the effect of acibenzolar-S-methyl (ASM) and ethylenebis (oxyethylenenitrilo) tetraacetic acid (EGTA) treatments on calcium-dependent protein kinases (CDPKs) and reactive oxygen species (ROS) metabolism in apples. Postharvest ASM treatment increased H2O2 content, reduced glutathione and ascorbic acid contents, and NADPH oxidase, peroxidase, ascorbate peroxidase, superoxide dismutase and glutathione reductase activities and retarded catalase activity and MdCAT expression in apples. ASM treatment enhanced MdSOD, MdPOD, MdAPX, MdGR, MdCDPK1, MdCDPK4, MdCDPK5, MdCDPK7, and MdCDPK21 expressions in apples. However, EGTA + ASM treatments suppressed H2O2, glutathione and ascorbic acid contents, NADPH oxidase, peroxidase, superoxide dismutase, ascorbate peroxidase and glutathione reductase activities. EGTA + ASM treatments suppressed the selected genes expressions in ROS metabolism and CDPKs, but up-regulated MdCAT expression in apples. These findings suggest that CDPKs play a vital role in regulating ROS metabolism and involve in inducing resistance in apples by ASM.
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Affiliation(s)
- Jiabao Hou
- College of Food Science and Technology, Bohai University, Jinzhou 121013, PR China; National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, PR China
| | - Canying Li
- College of Food Science and Technology, Bohai University, Jinzhou 121013, PR China; National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, PR China
| | - Yuan Cheng
- College of Food Science and Technology, Bohai University, Jinzhou 121013, PR China; National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, PR China
| | - Chaonan Jiang
- College of Food Science and Technology, Bohai University, Jinzhou 121013, PR China; National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, PR China
| | - Yihan Li
- College of Food Science and Technology, Bohai University, Jinzhou 121013, PR China; National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, PR China
| | - Yonghong Ge
- College of Food Science and Technology, Bohai University, Jinzhou 121013, PR China; National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, PR China.
| | - Jianrong Li
- College of Food Science and Technology, Bohai University, Jinzhou 121013, PR China; National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, PR China.
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Sanchez F, Geffroy S, Norest M, Yau S, Moreau H, Grimsley N. Simplified Transformation of Ostreococcus tauri Using Polyethylene Glycol. Genes (Basel) 2019; 10:E399. [PMID: 31130696 PMCID: PMC6562926 DOI: 10.3390/genes10050399] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/16/2019] [Accepted: 05/21/2019] [Indexed: 12/21/2022] Open
Abstract
Ostreococcustauri is an easily cultured representative of unicellular algae (class Mamiellophyceae) that abound in oceans worldwide. Eight complete 13-22 Mb genomes of phylogenetically divergent species within this class are available, and their DNA sequences are nearly always present in metagenomic data produced from marine samples. Here we describe a simplified and robust transformation protocol for the smallest of these algae (O. tauri). Polyethylene glycol (PEG) treatment was much more efficient than the previously described electroporation protocol. Short (2 min or less) incubation times in PEG gave >104 transformants per microgram DNA. The time of cell recovery after transformation could be reduced to a few hours, permitting the experiment to be done in a day rather than overnight as used in previous protocols. DNA was randomly inserted in the O. tauri genome. In our hands PEG was 20-40-fold more efficient than electroporation for the transformation of O. tauri, and this improvement will facilitate mutagenesis of all of the dispensable genes present in the tiny O. tauri genome.
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Affiliation(s)
- Frédéric Sanchez
- CNRS UMR7232 BIOM (Biologie Intégrative des Organismes Marin) Sorbonne University, 66650 Banyuls sur Mer, France.
| | - Solène Geffroy
- IFREMER, Centre Atlantique, 44331 Nantes CEDEX 03, France.
| | - Manon Norest
- CNRS UMR7232 BIOM (Biologie Intégrative des Organismes Marin) Sorbonne University, 66650 Banyuls sur Mer, France.
| | - Sheree Yau
- CNRS UMR7232 BIOM (Biologie Intégrative des Organismes Marin) Sorbonne University, 66650 Banyuls sur Mer, France.
| | - Hervé Moreau
- CNRS UMR7232 BIOM (Biologie Intégrative des Organismes Marin) Sorbonne University, 66650 Banyuls sur Mer, France.
| | - Nigel Grimsley
- CNRS UMR7232 BIOM (Biologie Intégrative des Organismes Marin) Sorbonne University, 66650 Banyuls sur Mer, France.
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Li Y, Fei X, Dai H, Li J, Zhu W, Deng X. Genome-Wide Identification of Calcium-Dependent Protein Kinases in Chlamydomonas reinhardtii and Functional Analyses in Nitrogen Deficiency-Induced Oil Accumulation. FRONTIERS IN PLANT SCIENCE 2019; 10:1147. [PMID: 31695707 PMCID: PMC6818280 DOI: 10.3389/fpls.2019.01147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 08/22/2019] [Indexed: 05/15/2023]
Abstract
Calcium-dependent protein kinases (CDPKs) are recognized as important calcium (Ca2+) sensors in signal transduction and play multiple roles in plant growth and developmental processes, as well as in response to various environmental stresses. However, little information is available about the CDPK family in the green microalga Chlamydomonas reinhardtii. In this study, 15 CrCDPK genes were identified in C. reinhardtii genome, and their functions in nitrogen (N) deficiency-induced oil accumulation were analyzed. Our results showed that all CrCDPK proteins harbored the typical elongation factor (EF)-hand Ca2+-binding and protein kinase domains. Phylogenetic analysis revealed that these CrCDPKs were clustered into one group together with a subclade of several CPKs from Arabidopsis and rice, clearly separating from the remaining AtCPKs and OsCPKs. These genes were located in 10 chromosomes and one scaffold of C. reinhardtii and contained 6-17 exons. RNA sequencing and quantitative reverse transcription (qRT)-PCR assays indicated that most of these CrCDPKs were significantly induced by N deficiency and salt stress. Lanthanum chloride (LaCl3), a plasma membrane Ca2+ channel blocker, limited oil accumulation in C. reinhardtii under N-deficient conditions, suggesting that Ca2+ was involved in N deficiency-induced oil accumulation. Furthermore, RNA interference (RNAi) silencing analyses demonstrated that six CrCDPKs played positive roles and three CrCDPKs played negative roles in N deficiency-induced oil accumulation in C. reinhardtii.
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Affiliation(s)
- Yajun Li
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Xiaowen Fei
- Biochemistry and Molecular Biology Department, Hainan Medical College, Haikou, China
| | - Haofu Dai
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Jiangyue Li
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Weiju Zhu
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Xiaodong Deng
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
- *Correspondence: Xiaodong Deng,
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Prasinovirus Attack of Ostreococcus Is Furtive by Day but Savage by Night. J Virol 2018; 92:JVI.01703-17. [PMID: 29187539 PMCID: PMC5790953 DOI: 10.1128/jvi.01703-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/09/2017] [Indexed: 12/12/2022] Open
Abstract
Prasinoviruses are large DNA viruses that infect diverse genera of green microalgae worldwide in aquatic ecosystems, but molecular knowledge of their life cycles is lacking. Several complete genomes of both these viruses and their marine algal hosts are now available and have been used to show the pervasive presence of these species in microbial metagenomes. We have analyzed the life cycle of Ostreococcus tauri virus 5 (OtV5), a lytic virus, using transcriptome sequencing (RNA-Seq) from 12 time points of healthy or infected Ostreococcus tauri cells over a day/night cycle in culture. In the day, viral gene transcription remained low while host nitrogen metabolism gene transcription was initially strongly repressed for two successive time points before being induced for 8 h, but during the night, viral transcription increased steeply while host nitrogen metabolism genes were repressed and many host functions that are normally reduced in the dark appeared to be compensated either by genes expressed from the virus or by increased expression of a subset of 4.4% of the host's genes. Some host cells underwent lysis progressively during the night, but a larger proportion were lysed the following morning. Our data suggest that the life cycles of algal viruses mirror the diurnal rhythms of their hosts.IMPORTANCE Prasinoviruses are common in marine environments, and although several complete genomes of these viruses and their hosts have been characterized, little is known about their life cycles. Here we analyze in detail the transcriptional changes occurring over a 27-h-long experiment in a natural diurnal rhythm, in which the growth of host cells is to some extent synchronized, so that host DNA replication occurs late in the day or early in the night and cell division occurs during the night. Surprisingly, viral transcription remains quiescent over the daytime, when the most energy (from light) is available, but during the night viral transcription activates, accompanied by expression of a few host genes that are probably required by the virus. Although our experiment was accomplished in the lab, cyclical changes have been documented in host transcription in the ocean. Our observations may thus be relevant for eukaryotic phytoplankton in natural environments.
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