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Jin P, Ji Y, Huang Q, Li P, Pan J, Lu H, Liang Z, Guo Y, Zhong J, Beardall J, Xia J. A reduction in metabolism explains the tradeoffs associated with the long-term adaptation of phytoplankton to high CO 2 concentrations. THE NEW PHYTOLOGIST 2022; 233:2155-2167. [PMID: 34907539 DOI: 10.1111/nph.17917] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 11/28/2021] [Indexed: 06/14/2023]
Abstract
Phytoplankton are responsible for nearly half of global primary productivity and play crucial roles in the Earth's biogeochemical cycles. However, the long-term adaptive responses of phytoplankton to rising CO2 remains unknown. Here we examine the physiological and proteomics responses of a marine diatom, Phaeodactylum tricornutum, following long-term (c. 900 generations) selection to high CO2 conditions. Our results show that this diatom responds to long-term high CO2 selection by downregulating proteins involved in energy production (Calvin cycle, tricarboxylic acid cycle, glycolysis, oxidative pentose phosphate pathway), with a subsequent decrease in photosynthesis and respiration. Nearly similar extents of downregulation of photosynthesis and respiration allow the high CO2 -adapted populations to allocate the same fraction of carbon to growth, thereby maintaining their fitness during the long-term high CO2 selection. These results indicate an important role of metabolism reduction under high CO2 and shed new light on the adaptive mechanisms of phytoplankton in response to climate change.
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Affiliation(s)
- Peng Jin
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Yan Ji
- School of Biological & Chemical Engineering, Qingdao Technical College, Qingdao, 266555, China
| | - Quanting Huang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Peiyuan Li
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Jinmei Pan
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Hua Lu
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Zhe Liang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Yingyan Guo
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Jiahui Zhong
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton, Vic, 3800, Australia
| | - Jianrong Xia
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
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2
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Hippmann AA, Schuback N, Moon K, McCrow JP, Allen AE, Foster LF, Green BR, Maldonado MT. Proteomic analysis of metabolic pathways supports chloroplast-mitochondria cross-talk in a Cu-limited diatom. PLANT DIRECT 2022; 6:e376. [PMID: 35079683 PMCID: PMC8777261 DOI: 10.1002/pld3.376] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 05/19/2023]
Abstract
Diatoms are one of the most successful phytoplankton groups in our oceans, being responsible for over 20% of the Earth's photosynthetic productivity. Their chimeric genomes have genes derived from red algae, green algae, bacteria, and heterotrophs, resulting in multiple isoenzymes targeted to different cellular compartments with the potential for differential regulation under nutrient limitation. The resulting interactions between metabolic pathways are not yet fully understood. We previously showed how acclimation to Cu limitation enhanced susceptibility to overreduction of the photosynthetic electron transport chain and its reorganization to favor photoprotection over light harvesting in the oceanic diatom Thalassiosira oceanica (Hippmann et al., 2017, 10.1371/journal.pone.0181753). In order to gain a better understanding of the overall metabolic changes that help alleviate the stress of Cu limitation, we have further analyzed the comprehensive proteomic datasets generated in that study to identify differentially expressed proteins involved in carbon, nitrogen, and oxidative stress-related metabolic pathways. Metabolic pathway analysis showed integrated responses to Cu limitation. The upregulation of ferredoxin (Fdx) was correlated with upregulation of plastidial Fdx-dependent isoenzymes involved in nitrogen assimilation as well as enzymes involved in glutathione synthesis, thus suggesting an integration of nitrogen uptake and metabolism with photosynthesis and oxidative stress resistance. The differential expression of glycolytic isoenzymes located in the chloroplast and mitochondria may enable them to channel both excess electrons and/or ATP between these compartments. An additional support for chloroplast-mitochondrial cross-talk is the increased expression of chloroplast and mitochondrial proteins involved in the proposed malate shunt under Cu limitation.
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Affiliation(s)
- Anna A. Hippmann
- Department of Earth Ocean and Atmospheric ScienceUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Nina Schuback
- Department of Earth Ocean and Atmospheric ScienceUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Kyung‐Mee Moon
- Biochemistry and Molecular BiologyMichael Smith LaboratoriesVancouverBritish ColumbiaCanada
| | - John P. McCrow
- Microbial and Environmental GenomicsJ. Craig Venter InstituteLa JollaCAUSA
| | - Andrew E. Allen
- Microbial and Environmental GenomicsJ. Craig Venter InstituteLa JollaCAUSA
- Scripps Institution of OceanographyUniversity of CaliforniaSan DiegoCAUSA
| | - Leonard F. Foster
- Biochemistry and Molecular BiologyMichael Smith LaboratoriesVancouverBritish ColumbiaCanada
| | - Beverley R. Green
- Department of BotanyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Maria T. Maldonado
- Department of Earth Ocean and Atmospheric ScienceUniversity of British ColumbiaVancouverBritish ColumbiaCanada
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3
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Gruber A, Haferkamp I. Nucleotide Transport and Metabolism in Diatoms. Biomolecules 2019; 9:E761. [PMID: 31766535 PMCID: PMC6995639 DOI: 10.3390/biom9120761] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/11/2019] [Accepted: 11/18/2019] [Indexed: 01/01/2023] Open
Abstract
Plastids, organelles that evolved from cyanobacteria via endosymbiosis in eukaryotes, provide carbohydrates for the formation of biomass and for mitochondrial energy production to the cell. They generate their own energy in the form of the nucleotide adenosine triphosphate (ATP). However, plastids of non-photosynthetic tissues, or during the dark, depend on external supply of ATP. A dedicated antiporter that exchanges ATP against adenosine diphosphate (ADP) plus inorganic phosphate (Pi) takes over this function in most photosynthetic eukaryotes. Additional forms of such nucleotide transporters (NTTs), with deviating activities, are found in intracellular bacteria, and, surprisingly, also in diatoms, a group of algae that acquired their plastids from other eukaryotes via one (or even several) additional endosymbioses compared to algae with primary plastids and higher plants. In this review, we summarize what is known about the nucleotide synthesis and transport pathways in diatom cells, and discuss the evolutionary implications of the presence of the additional NTTs in diatoms, as well as their applications in biotechnology.
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Affiliation(s)
- Ansgar Gruber
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 1160/31, 370 05 České Budějovice, Czech Republic
| | - Ilka Haferkamp
- Pflanzenphysiologie, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany;
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4
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Schober AF, R�o B�rtulos C, Bischoff A, Lepetit B, Gruber A, Kroth PG. Organelle Studies and Proteome Analyses of Mitochondria and Plastids Fractions from the Diatom Thalassiosira pseudonana. PLANT & CELL PHYSIOLOGY 2019; 60:1811-1828. [PMID: 31179502 PMCID: PMC6683858 DOI: 10.1093/pcp/pcz097] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/14/2019] [Indexed: 05/19/2023]
Abstract
Diatoms are unicellular algae and evolved by secondary endosymbiosis, a process in which a red alga-like eukaryote was engulfed by a heterotrophic eukaryotic cell. This gave rise to plastids of remarkable complex architecture and ultrastructure that require elaborate protein importing, trafficking, signaling and intracellular cross-talk pathways. Studying both plastids and mitochondria and their distinctive physiological pathways in organello may greatly contribute to our understanding of photosynthesis, mitochondrial respiration and diatom evolution. The isolation of such complex organelles, however, is still demanding, and existing protocols are either limited to a few species (for plastids) or have not been reported for diatoms so far (for mitochondria). In this work, we present the first isolation protocol for mitochondria from the model diatom Thalassiosira pseudonana. Apart from that, we extended the protocol so that it is also applicable for the purification of a high-quality plastids fraction, and provide detailed structural and physiological characterizations of the resulting organelles. Isolated mitochondria were structurally intact, showed clear evidence of mitochondrial respiration, but the fractions still contained residual cell fragments. In contrast, plastid isolates were virtually free of cellular contaminants, featured structurally preserved thylakoids performing electron transport, but lost most of their stromal components as concluded from Western blots and mass spectrometry. Liquid chromatography electrospray-ionization mass spectrometry studies on mitochondria and thylakoids, moreover, allowed detailed proteome analyses which resulted in extensive proteome maps for both plastids and mitochondria thus helping us to broaden our understanding of organelle metabolism and functionality in diatoms.
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Affiliation(s)
- Alexander F Schober
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, Germany
- Corresponding author: E-mail, ; Fax, +49(0)7531-88-4047
| | - Carolina R�o B�rtulos
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Annsophie Bischoff
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Bernard Lepetit
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Ansgar Gruber
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, Germany
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovsk� 1160/31, Česk� Budějovice, Czech Republic
| | - Peter G Kroth
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, Germany
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5
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Río Bártulos C, Rogers MB, Williams TA, Gentekaki E, Brinkmann H, Cerff R, Liaud MF, Hehl AB, Yarlett NR, Gruber A, Kroth PG, van der Giezen M. Mitochondrial Glycolysis in a Major Lineage of Eukaryotes. Genome Biol Evol 2018; 10:2310-2325. [PMID: 30060189 PMCID: PMC6198282 DOI: 10.1093/gbe/evy164] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2018] [Indexed: 12/21/2022] Open
Abstract
The establishment of the mitochondrion is seen as a transformational step in the origin of eukaryotes. With the mitochondrion came bioenergetic freedom to explore novel evolutionary space leading to the eukaryotic radiation known today. The tight integration of the bacterial endosymbiont with its archaeal host was accompanied by a massive endosymbiotic gene transfer resulting in a small mitochondrial genome which is just a ghost of the original incoming bacterial genome. This endosymbiotic gene transfer resulted in the loss of many genes, both from the bacterial symbiont as well the archaeal host. Loss of genes encoding redundant functions resulted in a replacement of the bulk of the host’s metabolism for those originating from the endosymbiont. Glycolysis is one such metabolic pathway in which the original archaeal enzymes have been replaced by bacterial enzymes from the endosymbiont. Glycolysis is a major catabolic pathway that provides cellular energy from the breakdown of glucose. The glycolytic pathway of eukaryotes appears to be bacterial in origin, and in well-studied model eukaryotes it takes place in the cytosol. In contrast, here we demonstrate that the latter stages of glycolysis take place in the mitochondria of stramenopiles, a diverse and ecologically important lineage of eukaryotes. Although our work is based on a limited sample of stramenopiles, it leaves open the possibility that the mitochondrial targeting of glycolytic enzymes in stramenopiles might represent the ancestral state for eukaryotes.
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Affiliation(s)
- Carolina Río Bártulos
- Institut für Genetik, Technische Universität Braunschweig.,Fachbereich Biologie, Universität Konstanz, Germany
| | - Matthew B Rogers
- Biosciences, University of Exeter, United Kingdom.,Rangos Research Center, University of Pittsburgh, Children's Hospital, Pittsburgh, PA
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, United Kingdom
| | - Eleni Gentekaki
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Canada.,School of Science and Human Gut Microbiome for Health Research Unit, Mae Fah Luang University, Chiang Rai, Thailand
| | - Henner Brinkmann
- Département de Biochimie, Université de Montréal C.P. 6128, Montréal, Quebec, Canada.,Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Germany
| | - Rüdiger Cerff
- Institut für Genetik, Technische Universität Braunschweig
| | | | - Adrian B Hehl
- Institute of Parasitology, University of Zürich, Switzerland
| | - Nigel R Yarlett
- Department of Chemistry and Physical Sciences, Pace University
| | - Ansgar Gruber
- Fachbereich Biologie, Universität Konstanz, Germany.,Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Canada.,Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
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6
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Ewe D, Tachibana M, Kikutani S, Gruber A, Río Bártulos C, Konert G, Kaplan A, Matsuda Y, Kroth PG. The intracellular distribution of inorganic carbon fixing enzymes does not support the presence of a C4 pathway in the diatom Phaeodactylum tricornutum. PHOTOSYNTHESIS RESEARCH 2018; 137:263-280. [PMID: 29572588 DOI: 10.1007/s11120-018-0500-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/18/2018] [Indexed: 05/20/2023]
Abstract
Diatoms are unicellular algae and important primary producers. The process of carbon fixation in diatoms is very efficient even though the availability of dissolved CO2 in sea water is very low. The operation of a carbon concentrating mechanism (CCM) also makes the more abundant bicarbonate accessible for photosynthetic carbon fixation. Diatoms possess carbonic anhydrases as well as metabolic enzymes potentially involved in C4 pathways; however, the question as to whether a C4 pathway plays a general role in diatoms is not yet solved. While genome analyses indicate that the diatom Phaeodactylum tricornutum possesses all the enzymes required to operate a C4 pathway, silencing of the pyruvate orthophosphate dikinase (PPDK) in a genetically transformed cell line does not lead to reduced photosynthetic carbon fixation. In this study, we have determined the intracellular location of all enzymes potentially involved in C4-like carbon fixing pathways in P. tricornutum by expression of the respective proteins fused to green fluorescent protein (GFP), followed by fluorescence microscopy. Furthermore, we compared the results to known pathways and locations of enzymes in higher plants performing C3 or C4 photosynthesis. This approach revealed that the intracellular distribution of the investigated enzymes is quite different from the one observed in higher plants. In particular, the apparent lack of a plastidic decarboxylase in P. tricornutum indicates that this diatom does not perform a C4-like CCM.
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Affiliation(s)
- Daniela Ewe
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany.
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic.
| | - Masaaki Tachibana
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan
- Lion Corporation Pharmaceutical Laboratories No.1, Odawara, Kanagawa, 256-0811, Japan
| | - Sae Kikutani
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan
- Tech Manage Corp., Tokyo, 160-0023, Japan
| | - Ansgar Gruber
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Czech Republic
| | | | - Grzegorz Konert
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus-Givat Ram, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
| | - Yusuke Matsuda
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan
| | - Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
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7
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Moog D. In Silico Tools for the Prediction of Protein Import into Secondary Plastids. Methods Mol Biol 2018; 1829:381-394. [PMID: 29987735 DOI: 10.1007/978-1-4939-8654-5_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The in silico identification of proteins targeting to secondary plastids is a difficult task. Such plastids are complex in structure and can be surrounded by up to four membranes, which have to be crossed during import. Nucleus-encoded plastidial preproteins in organisms with secondary plastids contain specific N-terminal targeting signals, the so-called bipartite targeting signal (BTS) sequences consisting of a classical signal peptide followed by a transit peptide-like sequence, mediating this intricate process. As these signal sequences differ significantly from transit peptides of plastid preproteins in plants and other organisms with primary plastids, existing in silico tools for primary plastid targeting prediction are not directly suitable to detect nucleus-encoded proteins destined for the import into secondary plastids. In this chapter I describe the current state-of-the-art methods to reliably predict proteins that might be imported into secondary plastids of red- and green-algal origin using either the "classical" approach, which involves a combination of bits of information produced by existing in silico tools, or, if available, via consulting specifically developed algorithms.
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Affiliation(s)
- Daniel Moog
- Laboratory for Cell Biology, Philipps University Marburg, Marburg, Germany.
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8
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Gruber A, Kroth PG. Intracellular metabolic pathway distribution in diatoms and tools for genome-enabled experimental diatom research. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160402. [PMID: 28717012 PMCID: PMC5516111 DOI: 10.1098/rstb.2016.0402] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2017] [Indexed: 11/12/2022] Open
Abstract
Diatoms are important primary producers in the oceans and can also dominate other aquatic habitats. One reason for the success of this phylogenetically relatively young group of unicellular organisms could be the impressive redundancy and diversity of metabolic isoenzymes in diatoms. This redundancy is a result of the evolutionary origin of diatom plastids by a eukaryote-eukaryote endosymbiosis, a process that implies temporary redundancy of functionally complete eukaryotic genomes. During the establishment of the plastids, this redundancy was partially reduced via gene losses, and was partially retained via gene transfer to the nucleus of the respective host cell. These gene transfers required re-assignment of intracellular targeting signals, a process that simultaneously altered the intracellular distribution of metabolic enzymes compared with the ancestral cells. Genome annotation, the correct assignment of the gene products and the prediction of putative function, strongly depends on the correct prediction of the intracellular targeting of a gene product. Here again diatoms are very peculiar, because the targeting systems for organelle import are partially different to those in land plants. In this review, we describe methods of predicting intracellular enzyme locations, highlight findings of metabolic peculiarities in diatoms and present genome-enabled approaches to study their metabolism.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.
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Affiliation(s)
- Ansgar Gruber
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
| | - Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
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9
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Chu L, Gruber A, Ast M, Schmitz-Esser S, Altensell J, Neuhaus HE, Kroth PG, Haferkamp I. Shuttling of (deoxy-) purine nucleotides between compartments of the diatom Phaeodactylum tricornutum. THE NEW PHYTOLOGIST 2017; 213:193-205. [PMID: 27504715 DOI: 10.1111/nph.14126] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 06/25/2016] [Indexed: 05/10/2023]
Abstract
Diatom plastids show several peculiarities when compared with primary plastids of higher plants or algae. They are surrounded by four membranes and depend on nucleotide uptake because, unlike in plants, nucleotide de novo synthesis exclusively occurs in the cytosol. Previous analyses suggest that two specifically adapted nucleotide transporters (NTTs) facilitate the required passage of nucleotides across the innermost plastid membrane. However, nucleotide transport across the additional plastid membranes remains to be clarified. Phylogenetic studies, transport assays with the recombinant protein as well as GFP-based targeting analyses allowed detailed characterization of a novel isoform (PtNTT5) of the six NTTs of Phaeodactylum tricornutum. PtNTT5 exhibits low amino acid similarities and is only distantly related to all previously characterized NTTs. However, in a heterologous expression system, it acts as a nucleotide antiporter and prefers various (deoxy-) purine nucleotides as substrates. Interestingly, PtNTT5 is probably located in the endoplasmic reticulum, which in diatoms also represents the outermost plastid membrane. PtNTT5, with its unusual transport properties, phylogeny and localization, can be taken as further evidence for the establishment of a sophisticated and specifically adapted nucleotide transport system in diatom plastids.
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Affiliation(s)
- Lili Chu
- Pflanzliche Ökophysiologie, Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
| | - Ansgar Gruber
- Pflanzliche Ökophysiologie, Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
| | - Michelle Ast
- Pflanzenphysiologie, Technische Universität Kaiserslautern, 67653, Kaiserslautern, Germany
| | | | - Jacqueline Altensell
- Pflanzenphysiologie, Technische Universität Kaiserslautern, 67653, Kaiserslautern, Germany
| | - Horst Ekkehard Neuhaus
- Pflanzenphysiologie, Technische Universität Kaiserslautern, 67653, Kaiserslautern, Germany
| | - Peter G Kroth
- Pflanzliche Ökophysiologie, Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
| | - Ilka Haferkamp
- Pflanzenphysiologie, Technische Universität Kaiserslautern, 67653, Kaiserslautern, Germany
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10
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Gruber A, Rocap G, Kroth PG, Armbrust EV, Mock T. Plastid proteome prediction for diatoms and other algae with secondary plastids of the red lineage. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:519-28. [PMID: 25438865 PMCID: PMC4329603 DOI: 10.1111/tpj.12734] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 11/19/2014] [Accepted: 11/26/2014] [Indexed: 05/19/2023]
Abstract
The plastids of ecologically and economically important algae from phyla such as stramenopiles, dinoflagellates and cryptophytes were acquired via a secondary endosymbiosis and are surrounded by three or four membranes. Nuclear-encoded plastid-localized proteins contain N-terminal bipartite targeting peptides with the conserved amino acid sequence motif 'ASAFAP'. Here we identify the plastid proteomes of two diatoms, Thalassiosira pseudonana and Phaeodactylum tricornutum, using a customized prediction tool (ASAFind) that identifies nuclear-encoded plastid proteins in algae with secondary plastids of the red lineage based on the output of SignalP and the identification of conserved 'ASAFAP' motifs and transit peptides. We tested ASAFind against a large reference dataset of diatom proteins with experimentally confirmed subcellular localization and found that the tool accurately identified plastid-localized proteins with both high sensitivity and high specificity. To identify nucleus-encoded plastid proteins of T. pseudonana and P. tricornutum we generated optimized sets of gene models for both whole genomes, to increase the percentage of full-length proteins compared with previous assembly model sets. ASAFind applied to these optimized sets revealed that about 8% of the proteins encoded in their nuclear genomes were predicted to be plastid localized and therefore represent the putative plastid proteomes of these algae.
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Affiliation(s)
- Ansgar Gruber
- Fachbereich Biologie, Universität KonstanzKonstanz, 78457, Germany
| | - Gabrielle Rocap
- School of Oceanography, Center for Environmental Genomics, University of WashingtonSeattle, WA, 98195, USA
| | - Peter G Kroth
- Fachbereich Biologie, Universität KonstanzKonstanz, 78457, Germany
| | - E Virginia Armbrust
- School of Oceanography, Center for Environmental Genomics, University of WashingtonSeattle, WA, 98195, USA
| | - Thomas Mock
- School of Environmental Sciences, University of East AngliaNorwich Research Park, NR4 7TJ, Norwich, UK
- *
For correspondence (e-mail )
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