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Ray A, Kundu P, Ghosh A. Reconstruction of a Genome-Scale Metabolic Model of Scenedesmus obliquus and Its Application for Lipid Production under Three Trophic Modes. ACS Synth Biol 2023; 12:3463-3481. [PMID: 37852251 DOI: 10.1021/acssynbio.3c00516] [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: 10/20/2023]
Abstract
Green microalgae have emerged as beneficial feedstocks for biofuel production. A systems-level understanding of the biochemical network is needed to harness the microalgal metabolic capacity for bioproduction. Genome-scale metabolic modeling (GEM) showed immense potential in rational metabolic engineering, utilizing biochemical flux distribution analysis. Here, we report the first GEM for the green microalga, Scenedesmus obliquus (iAR632), a promising biodiesel feedstock with high lipid-storing capability. iAR632 comprises 1467 reactions, 734 metabolites, and 632 genes distributed among 7 compartments. The model was optimized under three different trophic modes of microalgal cultivation, i.e., autotrophy, mixotrophy, and heterotrophy. The robustness of the reconstructed network was confirmed by analyzing its sensitivity to the biomass components. Pathway-level flux profiles were analyzed, and significant flux space expansion was noticed majorly in reactions associated with lipid biosynthesis. In agreement with the experimental observation, iAR632 predicted about 3.8-fold increased biomass and almost 4-fold higher lipid under mixotrophy than the other trophic modes. Thus, the assessment of the condition-specific metabolic flux distribution of iAR632 suggested that mixotrophy is the preferred cultivation condition for improved microalgal growth and lipid production. Overall, the reconstructed GEM and subsequent analyses will provide a systematic framework for developing model-driven strategies to improve microalgal bioproduction.
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Affiliation(s)
- Ayusmita Ray
- P.K. Sinha Centre for Bioenergy and Renewables, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Pritam Kundu
- School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Amit Ghosh
- School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
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2
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Murison V, Hérault J, Côme M, Guinio S, Lebon A, Chamot C, Bénard M, Galas L, Schoefs B, Marchand J, Bardor M, Ulmann L. Comparison of two Phaeodactylum tricornutum ecotypes under nitrogen starvation and resupply reveals distinct lipid accumulation strategies but a common degradation process. FRONTIERS IN PLANT SCIENCE 2023; 14:1257500. [PMID: 37810403 PMCID: PMC10556672 DOI: 10.3389/fpls.2023.1257500] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/04/2023] [Indexed: 10/10/2023]
Abstract
Introduction Phaeodactylum tricornutum is a model species frequently used to study lipid metabolism in diatoms. When exposed to a nutrient limitation or starvation, diatoms are known to accumulate neutral lipids in cytoplasmic lipid droplets (LDs). Those lipids are produced partly de novo and partly from the recycle of plastid membrane lipids. Under a nitrogen resupply, the accumulated lipids are catabolized, a phenomenon about which only a few data are available. Various strains of P. tricornutum have been isolated around the world that may differ in lipid accumulation patterns. Methods To get further information on this topic, two genetically distant ecotypes of P. tricornutum (Pt1 and Pt4) have been cultivated under nitrogen deprivation during 11 days followed by a resupply period of 3 days. The importance of cytoplasmic LDs relative to the plastid was assessed by a combination of confocal laser scanning microscopy and cell volume estimation using bright field microscopy pictures. Results and discussion We observed that in addition to a basal population of small LDs (0.005 μm3 to 0.7 μm3) present in both strains all along the experiment, Pt4 cells immediately produced two large LDs (up to 12 μm3 after 11 days) while Pt1 cells progressively produced a higher number of smaller LDs (up to 7 μm3 after 11 days). In this work we showed that, in addition to intracellular available space, lipid accumulation may be limited by the pre-starvation size of the plastid as a source of membrane lipids to be recycled. After resupplying nitrogen and for both ecotypes, a fragmentation of the largest LDs was observed as well as a possible migration of LDs to the vacuoles that would suggest an autophagic degradation. Altogether, our results deepen the understanding of LDs dynamics and open research avenues for a better knowledge of lipid degradation in diatoms.
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Affiliation(s)
- Victor Murison
- Biology of Organisms, Stress, Health and Environment, IUT Département Génie Biologique, Le Mans Université, IUML-FR 3473 CNRS, Laval, France
| | - Josiane Hérault
- Biology of Organisms, Stress, Health and Environment, IUT Département Génie Biologique, Le Mans Université, IUML-FR 3473 CNRS, Laval, France
| | - Martine Côme
- Biology of Organisms, Stress, Health and Environment, IUT Département Génie Biologique, Le Mans Université, IUML-FR 3473 CNRS, Laval, France
| | - Sabrina Guinio
- Biology of Organisms, Stress, Health and Environment, IUT Département Génie Biologique, Le Mans Université, IUML-FR 3473 CNRS, Laval, France
| | - Alexis Lebon
- Université de Rouen Normandie, INSERM, CNRS, HeRacLeS US51 UAR2026, PRIMACEN, Rouen, France
| | - Christophe Chamot
- Université de Rouen Normandie, INSERM, CNRS, HeRacLeS US51 UAR2026, PRIMACEN, Rouen, France
| | - Magalie Bénard
- Université de Rouen Normandie, INSERM, CNRS, HeRacLeS US51 UAR2026, PRIMACEN, Rouen, France
| | - Ludovic Galas
- Université de Rouen Normandie, INSERM, CNRS, HeRacLeS US51 UAR2026, PRIMACEN, Rouen, France
| | - Benoît Schoefs
- Biology of Organisms, Stress, Health and Environment, UFR Sciences et Techniques, Le Mans Université, IUML-FR 3473 CNRS, Le Mans, France
| | - Justine Marchand
- Biology of Organisms, Stress, Health and Environment, UFR Sciences et Techniques, Le Mans Université, IUML-FR 3473 CNRS, Le Mans, France
| | - Muriel Bardor
- Université de Rouen Normandie, Laboratoire GlycoMEV UR4358, SFR Normandie Végétal FED 4277, Innovation Chimie Carnot, Rouen, France
| | - Lionel Ulmann
- Biology of Organisms, Stress, Health and Environment, IUT Département Génie Biologique, Le Mans Université, IUML-FR 3473 CNRS, Laval, France
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3
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Córdoba SC, Tong H, Burgos A, Zhu F, Alseekh S, Fernie AR, Nikoloski Z. Identification of gene function based on models capturing natural variability of Arabidopsis thaliana lipid metabolism. Nat Commun 2023; 14:4897. [PMID: 37580345 PMCID: PMC10425450 DOI: 10.1038/s41467-023-40644-9] [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: 03/17/2023] [Accepted: 08/04/2023] [Indexed: 08/16/2023] Open
Abstract
Lipids play fundamental roles in regulating agronomically important traits. Advances in plant lipid metabolism have until recently largely been based on reductionist approaches, although modulation of its components can have system-wide effects. However, existing models of plant lipid metabolism provide lumped representations, hindering detailed study of component modulation. Here, we present the Plant Lipid Module (PLM) which provides a mechanistic description of lipid metabolism in the Arabidopsis thaliana rosette. We demonstrate that the PLM can be readily integrated in models of A. thaliana Col-0 metabolism, yielding accurate predictions (83%) of single lethal knock-outs and 75% concordance between measured transcript and predicted flux changes under extended darkness. Genome-wide associations with fluxes obtained by integrating the PLM in diel condition- and accession-specific models identify up to 65 candidate genes modulating A. thaliana lipid metabolism. Using mutant lines, we validate up to 40% of the candidates, paving the way for identification of metabolic gene function based on models capturing natural variability in metabolism.
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Affiliation(s)
- Sandra Correa Córdoba
- Bioinformatics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
- Systems Biology and Mathematical Modelling, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany.
| | - Hao Tong
- Bioinformatics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Systems Biology and Mathematical Modelling, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Asdrúbal Burgos
- Department of Zoology and Botany, University of Guadalajara, Guadalajara, Mexico
| | - Feng Zhu
- National R&D Center for Citrus Preservation, Hubei Hongshan Laboratory, National Key Laboratory for Germplasm Innovation and Utilization for Horticultural Crops, Huazhong Agricultural University, Wuhan, China
| | - Saleh Alseekh
- Central Metabolism, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
- Center of Plant Systems Biology and Biotechnology, Plovdiv, 4000, Bulgaria
| | - Alisdair R Fernie
- Central Metabolism, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
- Center of Plant Systems Biology and Biotechnology, Plovdiv, 4000, Bulgaria
| | - Zoran Nikoloski
- Bioinformatics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
- Systems Biology and Mathematical Modelling, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany.
- Center of Plant Systems Biology and Biotechnology, Plovdiv, 4000, Bulgaria.
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4
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Cheng W, Hwang S, Guo Q, Qian L, Liu W, Yu Y, Liu L, Tao Y, Cao H. The Special and General Mechanism of Cyanobacterial Harmful Algal Blooms. Microorganisms 2023; 11:microorganisms11040987. [PMID: 37110410 PMCID: PMC10144548 DOI: 10.3390/microorganisms11040987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/29/2023] Open
Abstract
Cyanobacterial harmful algal blooms (CyanoHABs) are longstanding aquatic hazards worldwide, of which the mechanism is not yet fully understood, i.e., the process in which cyanobacteria establish dominance over coexisting algae in the same eutrophic waters. The dominance of CyanoHABs represents a deviation from their low abundance under conventional evolution in the oligotrophic state, which has been the case since the origin of cyanobacteria on early Earth. To piece together a comprehensive mechanism of CyanoHABs, we revisit the origin and adaptive radiation of cyanobacteria in oligotrophic Earth, demonstrating ubiquitous adaptive radiation enabled by corresponding biological functions under various oligotrophic conditions. Next, we summarize the biological functions (ecophysiology) which drive CyanoHABs and ecological evidence to synthesize a working mechanism at the population level (the special mechanism) for CyanoHABs: CyanoHABs are the consequence of the synergistic interaction between superior cyanobacterial ecophysiology and elevated nutrients. Interestingly, these biological functions are not a result of positive selection by water eutrophication, but an adaptation to a longstanding oligotrophic state as all the genes in cyanobacteria are under strong negative selection. Last, to address the relative dominance of cyanobacteria over coexisting algae, we postulate a "general" mechanism of CyanoHABs at the community level from an energy and matter perspective: cyanobacteria are simpler life forms and thus have lower per capita nutrient demand for growth than coexisting eukaryotic algae. We prove this by comparing cyanobacteria and eukaryotic algae in cell size and structure, genome size, size of genome-scale metabolic networks, cell content, and finally the golden standard-field studies with nutrient supplementation in the same waters. To sum up, the comprehensive mechanism of CyanoHABs comprises a necessary condition, which is the general mechanism, and a sufficient condition, which is the special mechanism. One prominent prediction based on this tentative comprehensive mechanism is that eukaryotic algal blooms will coexist with or replace CyanoHABs if eutrophication continues and goes over the threshold nutrient levels for eukaryotic algae. This two-fold comprehensive mechanism awaits further theoretic and experimental testing and provides an important guide to control blooms of all algal species.
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Affiliation(s)
- Wenduo Cheng
- Division of Natural and Applied Sciences, Duke Kunshan University, 8 Duke Ave, Kunshan 215316, China
| | - Somin Hwang
- Division of Natural and Applied Sciences, Duke Kunshan University, 8 Duke Ave, Kunshan 215316, China
| | - Qisen Guo
- Division of Natural and Applied Sciences, Duke Kunshan University, 8 Duke Ave, Kunshan 215316, China
| | - Leyuan Qian
- Division of Natural and Applied Sciences, Duke Kunshan University, 8 Duke Ave, Kunshan 215316, China
| | - Weile Liu
- Division of Natural and Applied Sciences, Duke Kunshan University, 8 Duke Ave, Kunshan 215316, China
| | - Yang Yu
- Division of Natural and Applied Sciences, Duke Kunshan University, 8 Duke Ave, Kunshan 215316, China
| | - Li Liu
- Division of Natural and Applied Sciences, Duke Kunshan University, 8 Duke Ave, Kunshan 215316, China
| | - Yi Tao
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Huansheng Cao
- Division of Natural and Applied Sciences, Duke Kunshan University, 8 Duke Ave, Kunshan 215316, China
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5
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Wendering P, Nikoloski Z. Toward mechanistic modeling and rational engineering of plant respiration. PLANT PHYSIOLOGY 2023; 191:2150-2166. [PMID: 36721968 PMCID: PMC10069892 DOI: 10.1093/plphys/kiad054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
Plant respiration not only provides energy to support all cellular processes, including biomass production, but also plays a major role in the global carbon cycle. Therefore, modulation of plant respiration can be used to both increase the plant yield and mitigate the effects of global climate change. Mechanistic modeling of plant respiration at sufficient biochemical detail can provide key insights for rational engineering of this process. Yet, despite its importance, plant respiration has attracted considerably less modeling effort in comparison to photosynthesis. In this update review, we highlight the advances made in modeling of plant respiration, emphasizing the gradual but important change from phenomenological to models based on first principles. We also provide a detailed account of the existing resources that can contribute to resolving the challenges in modeling plant respiration. These resources point at tangible improvements in the representation of cellular processes that contribute to CO2 evolution and consideration of kinetic properties of underlying enzymes to facilitate mechanistic modeling. The update review emphasizes the need to couple biochemical models of respiration with models of acclimation and adaptation of respiration for their effective usage in guiding breeding efforts and improving terrestrial biosphere models tailored to future climate scenarios.
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Affiliation(s)
- Philipp Wendering
- Systems Biology and Mathematical Modeling, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
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6
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Systems biology's role in leveraging microalgal biomass potential: Current status and future perspectives. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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7
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Broddrick JT, Ware MA, Jallet D, Palsson BO, Peers G. Integration of physiologically relevant photosynthetic energy flows into whole genome models of light-driven metabolism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:603-621. [PMID: 36053127 PMCID: PMC9826171 DOI: 10.1111/tpj.15965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 08/25/2022] [Accepted: 08/31/2022] [Indexed: 06/01/2023]
Abstract
Characterizing photosynthetic productivity is necessary to understand the ecological contributions and biotechnology potential of plants, algae, and cyanobacteria. Light capture efficiency and photophysiology have long been characterized by measurements of chlorophyll fluorescence dynamics. However, these investigations typically do not consider the metabolic network downstream of light harvesting. By contrast, genome-scale metabolic models capture species-specific metabolic capabilities but have yet to incorporate the rapid regulation of the light harvesting apparatus. Here, we combine chlorophyll fluorescence parameters defining photosynthetic and non-photosynthetic yield of absorbed light energy with a metabolic model of the pennate diatom Phaeodactylum tricornutum. This integration increases the model predictive accuracy regarding growth rate, intracellular oxygen production and consumption, and metabolic pathway usage. Through the quantification of excess electron transport, we uncover the sequential activation of non-radiative energy dissipation processes, cross-compartment electron shuttling, and non-photochemical quenching as the rapid photoacclimation strategy in P. tricornutum. Interestingly, the photon absorption thresholds that trigger the transition between these mechanisms were consistent at low and high incident photon fluxes. We use this understanding to explore engineering strategies for rerouting cellular resources and excess light energy towards bioproducts in silico. Overall, we present a methodology for incorporating a common, informative data type into computational models of light-driven metabolism and show its utilization within the design-build-test-learn cycle for engineering of photosynthetic organisms.
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Affiliation(s)
- Jared T. Broddrick
- Division of Biological SciencesUniversity of California, San DiegoLa JollaCA92093USA
- Department of BioengineeringUniversity of California, San DiegoLa JollaCA92093USA
- Space Biosciences Research BranchNASA Ames Research CenterMoffett FieldCA94035USA
| | - Maxwell A. Ware
- Department of BiologyColorado State UniversityFort CollinsCO80524USA
| | - Denis Jallet
- Department of BiologyColorado State UniversityFort CollinsCO80524USA
| | - Bernhard O. Palsson
- Department of BioengineeringUniversity of California, San DiegoLa JollaCA92093USA
| | - Graham Peers
- Department of BiologyColorado State UniversityFort CollinsCO80524USA
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8
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Dvoretsky DS, Temnov MS, Markin IV, Ustinskaya YV, Es’kova MA. Problems in the Development of Efficient Biotechnology for the Synthesis of Valuable Components from Microalgae Biomass. THEORETICAL FOUNDATIONS OF CHEMICAL ENGINEERING 2022. [DOI: 10.1134/s0040579522040224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Chen J, Huang Y, Shu Y, Hu X, Wu D, Jiang H, Wang K, Liu W, Fu W. Recent Progress on Systems and Synthetic Biology of Diatoms for Improving Algal Productivity. Front Bioeng Biotechnol 2022; 10:908804. [PMID: 35646842 PMCID: PMC9136054 DOI: 10.3389/fbioe.2022.908804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
Microalgae have drawn much attention for their potential applications as a sustainable source for developing bioactive compounds, functional foods, feeds, and biofuels. Diatoms, as one major group of microalgae with high yields and strong adaptability to the environment, have shown advantages in developing photosynthetic cell factories to produce value-added compounds, including heterologous bioactive products. However, the commercialization of diatoms has encountered several obstacles that limit the potential mass production, such as the limitation of algal productivity and low photosynthetic efficiency. In recent years, systems and synthetic biology have dramatically improved the efficiency of diatom cell factories. In this review, we discussed first the genome sequencing and genome-scale metabolic models (GEMs) of diatoms. Then, approaches to optimizing photosynthetic efficiency are introduced with a focus on the enhancement of biomass productivity in diatoms. We also reviewed genome engineering technologies, including CRISPR (clustered regularly interspaced short palindromic repeats) gene-editing to produce bioactive compounds in diatoms. Finally, we summarized the recent progress on the diatom cell factory for producing heterologous compounds through genome engineering to introduce foreign genes into host diatoms. This review also pinpointed the bottlenecks in algal engineering development and provided critical insights into the future direction of algal production.
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Affiliation(s)
- Jiwei Chen
- Department of Marine Science, Ocean College, Zhejiang University, Hangzhou, China
| | - Yifan Huang
- Department of Marine Science, Ocean College, Zhejiang University, Hangzhou, China
| | - Yuexuan Shu
- Department of Marine Science, Ocean College, Zhejiang University, Hangzhou, China
| | - Xiaoyue Hu
- Center for Data Science, Zhejiang University, Hangzhou, China
- School of Mathematical Sciences, Zhejiang University, Hangzhou, China
| | - Di Wu
- Department of Marine Science, Ocean College, Zhejiang University, Hangzhou, China
| | - Hangjin Jiang
- Center for Data Science, Zhejiang University, Hangzhou, China
| | - Kui Wang
- Department of Marine Science, Ocean College, Zhejiang University, Hangzhou, China
| | - Weihua Liu
- School of Mathematical Sciences, Zhejiang University, Hangzhou, China
| | - Weiqi Fu
- Department of Marine Science, Ocean College, Zhejiang University, Hangzhou, China
- Center for Systems Biology and Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
- *Correspondence: Weiqi Fu,
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10
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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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Passi A, Tibocha-Bonilla JD, Kumar M, Tec-Campos D, Zengler K, Zuniga C. Genome-Scale Metabolic Modeling Enables In-Depth Understanding of Big Data. Metabolites 2021; 12:14. [PMID: 35050136 PMCID: PMC8778254 DOI: 10.3390/metabo12010014] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/18/2021] [Accepted: 12/20/2021] [Indexed: 11/16/2022] Open
Abstract
Genome-scale metabolic models (GEMs) enable the mathematical simulation of the metabolism of archaea, bacteria, and eukaryotic organisms. GEMs quantitatively define a relationship between genotype and phenotype by contextualizing different types of Big Data (e.g., genomics, metabolomics, and transcriptomics). In this review, we analyze the available Big Data useful for metabolic modeling and compile the available GEM reconstruction tools that integrate Big Data. We also discuss recent applications in industry and research that include predicting phenotypes, elucidating metabolic pathways, producing industry-relevant chemicals, identifying drug targets, and generating knowledge to better understand host-associated diseases. In addition to the up-to-date review of GEMs currently available, we assessed a plethora of tools for developing new GEMs that include macromolecular expression and dynamic resolution. Finally, we provide a perspective in emerging areas, such as annotation, data managing, and machine learning, in which GEMs will play a key role in the further utilization of Big Data.
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Affiliation(s)
- Anurag Passi
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760, USA; (A.P.); (M.K.); (D.T.-C.); (K.Z.)
| | - Juan D. Tibocha-Bonilla
- Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760, USA;
| | - Manish Kumar
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760, USA; (A.P.); (M.K.); (D.T.-C.); (K.Z.)
| | - Diego Tec-Campos
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760, USA; (A.P.); (M.K.); (D.T.-C.); (K.Z.)
- Facultad de Ingeniería Química, Campus de Ciencias Exactas e Ingenierías, Universidad Autónoma de Yucatán, Merida 97203, Yucatan, Mexico
| | - Karsten Zengler
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760, USA; (A.P.); (M.K.); (D.T.-C.); (K.Z.)
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093-0412, USA
- Center for Microbiome Innovation, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0403, USA
| | - Cristal Zuniga
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760, USA; (A.P.); (M.K.); (D.T.-C.); (K.Z.)
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12
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Castillo T, Ramos D, García-Beltrán T, Brito-Bazan M, Galindo E. Mixotrophic cultivation of microalgae: An alternative to produce high-value metabolites. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.108183] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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13
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Rodenburg SYA, Seidl MF, de Ridder D, Govers F. Uncovering the Role of Metabolism in Oomycete-Host Interactions Using Genome-Scale Metabolic Models. Front Microbiol 2021; 12:748178. [PMID: 34707596 PMCID: PMC8543037 DOI: 10.3389/fmicb.2021.748178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/10/2021] [Indexed: 12/17/2022] Open
Abstract
Metabolism is the set of biochemical reactions of an organism that enables it to assimilate nutrients from its environment and to generate building blocks for growth and proliferation. It forms a complex network that is intertwined with the many molecular and cellular processes that take place within cells. Systems biology aims to capture the complexity of cells, organisms, or communities by reconstructing models based on information gathered by high-throughput analyses (omics data) and prior knowledge. One type of model is a genome-scale metabolic model (GEM) that allows studying the distributions of metabolic fluxes, i.e., the "mass-flow" through the network of biochemical reactions. GEMs are nowadays widely applied and have been reconstructed for various microbial pathogens, either in a free-living state or in interaction with their hosts, with the aim to gain insight into mechanisms of pathogenicity. In this review, we first introduce the principles of systems biology and GEMs. We then describe how metabolic modeling can contribute to unraveling microbial pathogenesis and host-pathogen interactions, with a specific focus on oomycete plant pathogens and in particular Phytophthora infestans. Subsequently, we review achievements obtained so far and identify and discuss potential pitfalls of current models. Finally, we propose a workflow for reconstructing high-quality GEMs and elaborate on the resources needed to advance a system biology approach aimed at untangling the intimate interactions between plants and pathogens.
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Affiliation(s)
- Sander Y. A. Rodenburg
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, Netherlands
- Bioinformatics Group, Wageningen University & Research, Wageningen, Netherlands
| | - Michael F. Seidl
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, Netherlands
- Theoretical Biology & Bioinformatics group, Department of Biology, Utrecht University, Wageningen, Netherlands
| | - Dick de Ridder
- Bioinformatics Group, Wageningen University & Research, Wageningen, Netherlands
| | - Francine Govers
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, Netherlands
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14
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Vavitsas K, Kugler A, Satta A, Hatzinikolaou DG, Lindblad P, Fewer DP, Lindberg P, Toivari M, Stensjö K. Doing synthetic biology with photosynthetic microorganisms. PHYSIOLOGIA PLANTARUM 2021; 173:624-638. [PMID: 33963557 DOI: 10.1111/ppl.13455] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/22/2021] [Accepted: 05/06/2021] [Indexed: 06/12/2023]
Abstract
The use of photosynthetic microbes as synthetic biology hosts for the sustainable production of commodity chemicals and even fuels has received increasing attention over the last decade. The number of studies published, tools implemented, and resources made available for microalgae have increased beyond expectations during the last few years. However, the tools available for genetic engineering in these organisms still lag those available for the more commonly used heterotrophic host organisms. In this mini-review, we provide an overview of the photosynthetic microbes most commonly used in synthetic biology studies, namely cyanobacteria, chlorophytes, eustigmatophytes and diatoms. We provide basic information on the techniques and tools available for each model group of organisms, we outline the state-of-the-art, and we list the synthetic biology tools that have been successfully used. We specifically focus on the latest CRISPR developments, as we believe that precision editing and advanced genetic engineering tools will be pivotal to the advancement of the field. Finally, we discuss the relative strengths and weaknesses of each group of organisms and examine the challenges that need to be overcome to achieve their synthetic biology potential.
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Affiliation(s)
- Konstantinos Vavitsas
- Enzyme and Microbial Biotechnology Unit, Department of Biology, National and Kapodistrian University of Athens, Zografou Campus, Athens, Greece
| | - Amit Kugler
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Alessandro Satta
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia
- CSIRO Synthetic Biology Future Science Platform, Brisbane, Australia
| | - Dimitris G Hatzinikolaou
- Enzyme and Microbial Biotechnology Unit, Department of Biology, National and Kapodistrian University of Athens, Zografou Campus, Athens, Greece
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - David P Fewer
- Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Pia Lindberg
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Mervi Toivari
- VTT, Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Karin Stensjö
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
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15
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Seif Y, Palsson BØ. Path to improving the life cycle and quality of genome-scale models of metabolism. Cell Syst 2021; 12:842-859. [PMID: 34555324 PMCID: PMC8480436 DOI: 10.1016/j.cels.2021.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 02/17/2021] [Accepted: 06/23/2021] [Indexed: 11/28/2022]
Abstract
Genome-scale models of metabolism (GEMs) are key computational tools for the systems-level study of metabolic networks. Here, we describe the "GEM life cycle," which we subdivide into four stages: inception, maturation, specialization, and amalgamation. We show how different types of GEM reconstruction workflows fit in each stage and proceed to highlight two fundamental bottlenecks for GEM quality improvement: GEM maturation and content removal. We identify common characteristics contributing to increasing quality of maturing GEMs drawing from past independent GEM maturation efforts. We then shed some much-needed light on the latent and unrecognized but pervasive issue of content removal, demonstrating the substantial effects of model pruning on its solution space. Finally, we propose a novel framework for content removal and associated confidence-level assignment which will help guide future GEM development efforts, reduce duplication of effort across groups, potentially aid automated reconstruction platforms, and boost the reproducibility of model development.
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Affiliation(s)
- Yara Seif
- Department of Bioengineering, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Bernhard Ørn Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, San Diego, CA 92093, USA.
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16
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Phylogenomic fingerprinting of tempo and functions of horizontal gene transfer within ochrophytes. Proc Natl Acad Sci U S A 2021; 118:2009974118. [PMID: 33419955 DOI: 10.1073/pnas.2009974118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Horizontal gene transfer (HGT) is an important source of novelty in eukaryotic genomes. This is particularly true for the ochrophytes, a diverse and important group of algae. Previous studies have shown that ochrophytes possess a mosaic of genes derived from bacteria and eukaryotic algae, acquired through chloroplast endosymbiosis and from HGTs, although understanding of the time points and mechanisms underpinning these transfers has been restricted by the depth of taxonomic sampling possible. We harness an expanded set of ochrophyte sequence libraries, alongside automated and manual phylogenetic annotation, in silico modeling, and experimental techniques, to assess the frequency and functions of HGT across this lineage. Through manual annotation of thousands of single-gene trees, we identify continuous bacterial HGT as the predominant source of recently arrived genes in the model diatom Phaeodactylum tricornutum Using a large-scale automated dataset, a multigene ochrophyte reference tree, and mathematical reconciliation of gene trees, we note a probable elevation of bacterial HGTs at foundational points in diatom evolution, following their divergence from other ochrophytes. Finally, we demonstrate that throughout ochrophyte evolutionary history, bacterial HGTs have been enriched in genes encoding secreted proteins. Our study provides insights into the sources and frequency of HGTs, and functional contributions that HGT has made to algal evolution.
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17
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Villanova V, Singh D, Pagliardini J, Fell D, Le Monnier A, Finazzi G, Poolman M. Boosting Biomass Quantity and Quality by Improved Mixotrophic Culture of the Diatom Phaeodactylum tricornutum. FRONTIERS IN PLANT SCIENCE 2021; 12:642199. [PMID: 33897733 PMCID: PMC8063856 DOI: 10.3389/fpls.2021.642199] [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: 12/15/2020] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
Diatoms are photoautotrophic unicellular algae and are among the most abundant, adaptable, and diverse marine phytoplankton. They are extremely interesting not only for their ecological role but also as potential feedstocks for sustainable biofuels and high-value commodities such as omega fatty acids, because of their capacity to accumulate lipids. However, the cultivation of microalgae on an industrial scale requires higher cell densities and lipid accumulation than those found in nature to make the process economically viable. One of the known ways to induce lipid accumulation in Phaeodactylum tricornutum is nitrogen deprivation, which comes at the expense of growth inhibition and lower cell density. Thus, alternative ways need to be explored to enhance the lipid production as well as biomass density to make them sustainable at industrial scale. In this study, we have used experimental and metabolic modeling approaches to optimize the media composition, in terms of elemental composition, organic and inorganic carbon sources, and light intensity, that boost both biomass quality and quantity of P. tricornutum. Eventually, the optimized conditions were scaled-up to 2 L photobioreactors, where a better system control (temperature, pH, light, aeration/mixing) allowed a further improvement of the biomass capacity of P. tricornutum to 12 g/L.
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Affiliation(s)
- Valeria Villanova
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS), Commissariat á l'Énergie Atomique et aux Énergies Alternatives (CEA), Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Interdisciplinary Research Institute of Grenoble, CEA Grenoble, Grenoble, France
- Fermentalg SA, Libourne, France
| | - Dipali Singh
- Microbes in the Food Chain, Quadram Institute Biosciences, Norwich Research Park, Norwich, United Kingdom
- Cell System Modelling Group, Oxford Brookes University, Oxford, United Kingdom
| | | | - David Fell
- Cell System Modelling Group, Oxford Brookes University, Oxford, United Kingdom
| | | | - Giovanni Finazzi
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS), Commissariat á l'Énergie Atomique et aux Énergies Alternatives (CEA), Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Interdisciplinary Research Institute of Grenoble, CEA Grenoble, Grenoble, France
| | - Mark Poolman
- Cell System Modelling Group, Oxford Brookes University, Oxford, United Kingdom
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18
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Bhattacharjya R, Tiwari A, Marella TK, Bansal H, Srivastava S. New paradigm in diatom omics and genetic manipulation. BIORESOURCE TECHNOLOGY 2021; 325:124708. [PMID: 33487514 DOI: 10.1016/j.biortech.2021.124708] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
Diatoms are one of the most heterogeneous eukaryotic plankton known for regulating earth's biogeochemical cycles and maintaining the marine ecosystems ever since the late Eocene epoch. The advent of multidisciplinary omics approach has both epitomized and revolutionized the nature of their chimeric genetic toolkit, ecophysiology, and metabolic adaptability as well as their interaction with other communities. In addition, advanced functional annotation of transcriptomic and proteomic data using cutting edge bioinformatics tools together with high-resolution genome-scale mathematical modeling has effectively proven as the catapult in solving genetic bottlenecks in microbial as well as diatom exploration. In this review, a corroborative summation of the robust work done in manipulating, engineering, and sequencing of the diatom genomes besides underpinning the holistic application of omics in transcription and translation has been discussed in order to shrewd their multifarious novel potential in the field of biotechnology and provide an insight into their dynamic evolutionary relevance.
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Affiliation(s)
- Raya Bhattacharjya
- Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh 201313, India
| | - Archana Tiwari
- Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh 201313, India.
| | - Thomas Kiran Marella
- Algae Biomass Energy System Development Research Center (ABES), Tennodai, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Hina Bansal
- Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh 201313, India
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19
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Genome-scale metabolic model of the diatom Thalassiosira pseudonana highlights the importance of nitrogen and sulfur metabolism in redox balance. PLoS One 2021; 16:e0241960. [PMID: 33760840 PMCID: PMC7990286 DOI: 10.1371/journal.pone.0241960] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 03/03/2021] [Indexed: 12/22/2022] Open
Abstract
Diatoms are unicellular photosynthetic algae known to secrete organic matter that fuels secondary production in the ocean, though our knowledge of how their physiology impacts the composition of dissolved organic matter remains limited. Like all photosynthetic organisms, their use of light for energy and reducing power creates the challenge of avoiding cellular damage. To better understand the interplay between redox balance and organic matter secretion, we reconstructed a genome-scale metabolic model of Thalassiosira pseudonana strain CCMP 1335, a model for diatom molecular biology and physiology, with a 60-year history of studies. The model simulates the metabolic activities of 1,432 genes via a network of 2,792 metabolites produced through 6,079 reactions distributed across six subcellular compartments. Growth was simulated under different steady-state light conditions (5–200 μmol photons m-2 s-1) and in a batch culture progressing from exponential growth to nitrate-limitation and nitrogen-starvation. We used the model to examine the dissipation of reductants generated through light-dependent processes and found that when available, nitrate assimilation is an important means of dissipating reductants in the plastid; under nitrate-limiting conditions, sulfate assimilation plays a similar role. The use of either nitrate or sulfate uptake to balance redox reactions leads to the secretion of distinct organic nitrogen and sulfur compounds. Such compounds can be accessed by bacteria in the surface ocean. The model of the diatom Thalassiosira pseudonana provides a mechanistic explanation for the production of ecologically and climatologically relevant compounds that may serve as the basis for intricate, cross-kingdom microbial networks. Diatom metabolism has an important influence on global biogeochemistry; metabolic models of marine microorganisms link genes to ecosystems and may be key to integrating molecular data with models of ocean biogeochemistry.
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20
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Simensen V, Voigt A, Almaas E. High-quality genome-scale metabolic model of Aurantiochytrium sp. T66. Biotechnol Bioeng 2021; 118:2105-2117. [PMID: 33624839 DOI: 10.1002/bit.27726] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/21/2021] [Accepted: 02/14/2021] [Indexed: 01/17/2023]
Abstract
The long-chain, ω-3 polyunsaturated fatty acids (PUFAs) (e.g., eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]), are essential for humans and animals, including marine fish species. Presently, the primary source of these PUFAs is fish oils. As the global production of fish oils appears to be reaching its limits, alternative sources of high-quality ω-3 PUFAs is paramount to support the growing aquaculture industry. Thraustochytrids are a group of heterotrophic protists with the capability to synthesize and accrue large amounts of DHA. Thus, the thraustochytrids are prime candidates to solve the increasing demand for ω-3 PUFAs using microbial cell factories. However, a systems-level understanding of their metabolic shift from cellular growth into lipid accumulation is, to a large extent, unclear. Here, we reconstructed a high-quality genome-scale metabolic model of the thraustochytrid Aurantiochytrium sp. T66 termed iVS1191. Through iterative rounds of model refinement and extensive manual curation, we significantly enhanced the metabolic scope and coverage of the reconstruction from that of previously published models, making considerable improvements with stoichiometric consistency, metabolic connectivity, and model annotations. We show that iVS1191 is highly consistent with experimental growth data, reproducing in vivo growth phenotypes as well as specific growth rates on minimal carbon media. The availability of iVS1191 provides a solid framework for further developing our understanding of T66's metabolic properties, as well as exploring metabolic engineering and process-optimization strategies in silico for increased ω-3 PUFA production.
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Affiliation(s)
- Vetle Simensen
- Department of Biotechnology and Food Science, NTNU - Norwegian University of Science and Technology, Trondheim, Norway
| | - André Voigt
- Department of Biotechnology and Food Science, NTNU - Norwegian University of Science and Technology, Trondheim, Norway
| | - Eivind Almaas
- Department of Biotechnology and Food Science, NTNU - Norwegian University of Science and Technology, Trondheim, Norway.,Department of Public Health and General Practice, K.G. Jebsen Center for Genetic Epidemiology, NTNU - Norwegian University of Science and Technology, Trondheim, Norway
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21
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Ahmad A, Tiwari A, Srivastava S. A Genome-Scale Metabolic Model of Thalassiosira pseudonana CCMP 1335 for a Systems-Level Understanding of Its Metabolism and Biotechnological Potential. Microorganisms 2020; 8:microorganisms8091396. [PMID: 32932853 PMCID: PMC7563145 DOI: 10.3390/microorganisms8091396] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/31/2020] [Accepted: 08/07/2020] [Indexed: 01/27/2023] Open
Abstract
Thalassiosira pseudonana is a transformable and biotechnologically promising model diatom with an ability to synthesise nutraceuticals such as fucoxanthin and store a significant amount of polyglucans and lipids including omega-3 fatty acids. While it was the first diatom to be sequenced, a systems-level analysis of its metabolism has not been done yet. This work presents first comprehensive, compartmentalized, and functional genome-scale metabolic model of the marine diatom Thalassiosira pseudonana CCMP 1335, which we have termed iThaps987. The model includes 987 genes, 2477 reactions, and 2456 metabolites. Comparison with the model of another diatom Phaeodactylum tricornutum revealed presence of 183 unique enzymes (belonging primarily to amino acid, carbohydrate, and lipid metabolism) in iThaps987. Model simulations showed a typical C3-type photosynthetic carbon fixation and suggested a preference of violaxanthin-diadinoxanthin pathway over violaxanthin-neoxanthin pathway for the production of fucoxanthin. Linear electron flow was found be active and cyclic electron flow was inactive under normal phototrophic conditions (unlike green algae and plants), validating the model predictions with previous reports. Investigation of the model for the potential of Thalassiosira pseudonana CCMP 1335 to produce other industrially useful compounds suggest iso-butanol as a foreign compound that can be synthesized by a single-gene addition. This work provides novel insights about the metabolism and potential of the organism and will be helpful to further investigate its metabolism and devise metabolic engineering strategies for the production of various compounds.
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Affiliation(s)
- Ahmad Ahmad
- Systems Biology for Biofuel Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India;
- Department of Biotechnology, Noida International University (NIU), Noida 203201, India
| | - Archana Tiwari
- Department of Biotechnology, Noida International University (NIU), Noida 203201, India
- Correspondence: (A.T.); (S.S.); Tel.: +91-958-264-9114 (A.T.); +91-11-2674-1361 (S.S.)
| | - Shireesh Srivastava
- Systems Biology for Biofuel Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India;
- Correspondence: (A.T.); (S.S.); Tel.: +91-958-264-9114 (A.T.); +91-11-2674-1361 (S.S.)
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22
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Metcalf AJ, Nagygyor A, Boyle NR. Rapid Annotation of Photosynthetic Systems (RAPS): automated algorithm to generate genome-scale metabolic networks from algal genomes. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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23
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24
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Correa SM, Fernie AR, Nikoloski Z, Brotman Y. Towards model-driven characterization and manipulation of plant lipid metabolism. Prog Lipid Res 2020; 80:101051. [PMID: 32640289 DOI: 10.1016/j.plipres.2020.101051] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 06/20/2020] [Accepted: 06/21/2020] [Indexed: 01/09/2023]
Abstract
Plant lipids have versatile applications and provide essential fatty acids in human diet. Therefore, there has been a growing interest to better characterize the genetic basis, regulatory networks, and metabolic pathways that shape lipid quantity and composition. Addressing these issues is challenging due to context-specificity of lipid metabolism integrating environmental, developmental, and tissue-specific cues. Here we systematically review the known metabolic pathways and regulatory interactions that modulate the levels of storage lipids in oilseeds. We argue that the current understanding of lipid metabolism provides the basis for its study in the context of genome-wide plant metabolic networks with the help of approaches from constraint-based modeling and metabolic flux analysis. The focus is on providing a comprehensive summary of the state-of-the-art of modeling plant lipid metabolic pathways, which we then contrast with the existing modeling efforts in yeast and microalgae. We then point out the gaps in knowledge of lipid metabolism, and enumerate the recent advances of using genome-wide association and quantitative trait loci mapping studies to unravel the genetic regulations of lipid metabolism. Finally, we offer a perspective on how advances in the constraint-based modeling framework can propel further characterization of plant lipid metabolism and its rational manipulation.
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Affiliation(s)
- Sandra M Correa
- Genetics of Metabolic Traits Group, Max Planck Institute for Molecular Plant Physiology, Potsdam 14476, Germany; Department of Life Sciences, Ben-Gurion University of the Negev, 8410501 Beer-Sheva, Israel; Departamento de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellín 050010, Colombia.
| | - Alisdair R Fernie
- Central Metabolism Group, Max Planck Institute for Molecular Plant Physiology, Potsdam 14476, Germany; Center of Plant Systems Biology and Biotechnology, Plovdiv, Bulgaria
| | - Zoran Nikoloski
- Center of Plant Systems Biology and Biotechnology, Plovdiv, Bulgaria; Bioinformatics, Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany; Systems Biology and Mathematical Modelling Group, Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm 14476, Germany.
| | - Yariv Brotman
- Genetics of Metabolic Traits Group, Max Planck Institute for Molecular Plant Physiology, Potsdam 14476, Germany; Department of Life Sciences, Ben-Gurion University of the Negev, 8410501 Beer-Sheva, Israel
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25
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Norsigian CJ, Pusarla N, McConn JL, Yurkovich JT, Dräger A, Palsson BO, King Z. BiGG Models 2020: multi-strain genome-scale models and expansion across the phylogenetic tree. Nucleic Acids Res 2020; 48:D402-D406. [PMID: 31696234 PMCID: PMC7145653 DOI: 10.1093/nar/gkz1054] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 10/21/2019] [Accepted: 10/24/2019] [Indexed: 01/04/2023] Open
Abstract
The BiGG Models knowledge base (http://bigg.ucsd.edu) is a centralized repository for high-quality genome-scale metabolic models. For the past 12 years, the website has allowed users to browse and search metabolic models. Within this update, we detail new content and features in the repository, continuing the original effort to connect each model to genome annotations and external databases as well as standardization of reactions and metabolites. We describe the addition of 31 new models that expand the portion of the phylogenetic tree covered by BiGG Models. We also describe new functionality for hosting multi-strain models, which have proven to be insightful in a variety of studies centered on comparisons of related strains. Finally, the models in the knowledge base have been benchmarked using Memote, a new community-developed validator for genome-scale models to demonstrate the improving quality and transparency of model content in BiGG Models.
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Affiliation(s)
- Charles J Norsigian
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Neha Pusarla
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - John Luke McConn
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Andreas Dräger
- Computational Systems Biology of Infection and Antimicrobial-Resistant Pathogens, Institute for Biomedical Informatics (IBMI), University of Tübingen, 72076 Tübingen, Germany.,Department of Computer Science, University of Tübingen, 72076 Tübingen, Germany.,German Center for Infection Research (DZIF), 72076 Tübingen, Germany
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA.,Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kongens Lyngby, Denmark
| | - Zachary King
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
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Dynamic resource allocation drives growth under nitrogen starvation in eukaryotes. NPJ Syst Biol Appl 2020; 6:14. [PMID: 32415097 PMCID: PMC7229059 DOI: 10.1038/s41540-020-0135-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 04/16/2020] [Indexed: 12/18/2022] Open
Abstract
Cells can sense changes in their extracellular environment and subsequently adapt their biomass composition. Nutrient abundance defines the capability of the cell to produce biomass components. Under nutrient-limited conditions, resource allocation dramatically shifts to carbon-rich molecules. Here, we used dynamic biomass composition data to predict changes in growth and reaction flux distributions using the available genome-scale metabolic models of five eukaryotic organisms (three heterotrophs and two phototrophs). We identified temporal profiles of metabolic fluxes that indicate long-term trends in pathway and organelle function in response to nitrogen depletion. Surprisingly, our calculations of model sensitivity and biosynthetic cost showed that free energy of biomass metabolites is the main driver of biosynthetic cost and not molecular weight, thus explaining the high costs of arginine and histidine. We demonstrated how metabolic models can accurately predict the complexity of interwoven mechanisms in response to stress over the course of growth.
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27
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Functional Genomics Differentiate Inherent and Environmentally Influenced Traits in Dinoflagellate and Diatom Communities. Microorganisms 2020; 8:microorganisms8040567. [PMID: 32326461 PMCID: PMC7232425 DOI: 10.3390/microorganisms8040567] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/07/2020] [Accepted: 04/09/2020] [Indexed: 12/13/2022] Open
Abstract
Dinoflagellates and diatoms are among the most prominent microeukaryotic plankton groups, and they have evolved different functional traits reflecting their roles within ecosystems. However, links between their metabolic processes and functional traits within different environmental contexts warrant further study. The functional biodiversity of dinoflagellates and diatoms was accessed with metatranscriptomics using Pfam protein domains as proxies for functional processes. Despite the overall geographic similarity of functional responses, abiotic (i.e., temperature and salinity; ~800 Pfam domains) and biotic (i.e., taxonomic group; ~1500 Pfam domains) factors influencing particular functional responses were identified. Salinity and temperature were identified as the main drivers of community composition. Higher temperatures were associated with an increase of Pfam domains involved in energy metabolism and a decrease of processes associated with translation and the sulfur cycle. Salinity changes were correlated with the biosynthesis of secondary metabolites (e.g., terpenoids and polyketides) and signal transduction processes, indicating an overall strong effect on the biota. The abundance of dinoflagellates was positively correlated with nitrogen metabolism, vesicular transport and signal transduction, highlighting their link to biotic interactions (more so than diatoms) and suggesting the central role of species interactions in the evolution of dinoflagellates. Diatoms were associated with metabolites (e.g., isoprenoids and carotenoids), as well as lysine degradation, which highlights their ecological role as important primary producers and indicates the physiological importance of these metabolic pathways for diatoms in their natural environment. These approaches and gathered information will support ecological questions concerning the marine ecosystem state and metabolic interactions in the marine environment.
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Ng I, Keskin BB, Tan S. A Critical Review of Genome Editing and Synthetic Biology Applications in Metabolic Engineering of Microalgae and Cyanobacteria. Biotechnol J 2020; 15:e1900228. [DOI: 10.1002/biot.201900228] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/07/2020] [Indexed: 12/13/2022]
Affiliation(s)
- I‐Son Ng
- Department of Chemical EngineeringNational Cheng Kung University Tainan 701 Taiwan
| | - Batuhan Birol Keskin
- Department of Chemical EngineeringNational Cheng Kung University Tainan 701 Taiwan
| | - Shih‐I Tan
- Department of Chemical EngineeringNational Cheng Kung University Tainan 701 Taiwan
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Falciatore A, Jaubert M, Bouly JP, Bailleul B, Mock T. Diatom Molecular Research Comes of Age: Model Species for Studying Phytoplankton Biology and Diversity. THE PLANT CELL 2020; 32:547-572. [PMID: 31852772 PMCID: PMC7054031 DOI: 10.1105/tpc.19.00158] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 10/18/2019] [Accepted: 12/13/2019] [Indexed: 05/08/2023]
Abstract
Diatoms are the world's most diverse group of algae, comprising at least 100,000 species. Contributing ∼20% of annual global carbon fixation, they underpin major aquatic food webs and drive global biogeochemical cycles. Over the past two decades, Thalassiosira pseudonana and Phaeodactylum tricornutum have become the most important model systems for diatom molecular research, ranging from cell biology to ecophysiology, due to their rapid growth rates, small genomes, and the cumulative wealth of associated genetic resources. To explore the evolutionary divergence of diatoms, additional model species are emerging, such as Fragilariopsis cylindrus and Pseudo-nitzschia multistriata Here, we describe how functional genomics and reverse genetics have contributed to our understanding of this important class of microalgae in the context of evolution, cell biology, and metabolic adaptations. Our review will also highlight promising areas of investigation into the diversity of these photosynthetic organisms, including the discovery of new molecular pathways governing the life of secondary plastid-bearing organisms in aquatic environments.
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Affiliation(s)
- Angela Falciatore
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, France
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR7238 Sorbonne Université, 75005 Paris, France
| | - Marianne Jaubert
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, France
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR7238 Sorbonne Université, 75005 Paris, France
| | - Jean-Pierre Bouly
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, France
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR7238 Sorbonne Université, 75005 Paris, France
| | - Benjamin Bailleul
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, France
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
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Bjerkelund Røkke G, Hohmann-Marriott MF, Almaas E. An adjustable algal chloroplast plug-and-play model for genome-scale metabolic models. PLoS One 2020; 15:e0229408. [PMID: 32092117 PMCID: PMC7039451 DOI: 10.1371/journal.pone.0229408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/05/2020] [Indexed: 01/25/2023] Open
Abstract
The chloroplast is a central part of plant cells, as this is the organelle where the photosynthesis, fixation of inorganic carbon, and other key functions related to fatty acid synthesis and amino acid synthesis occur. Since this organelle should be an integral part of any genome-scale metabolic model for a microalgae or a higher plant, it is of great interest to generate a detailed and standardized chloroplast model. Additionally, we see the need for a novel type of sub-model template, or organelle model, which could be incorporated into a larger, less specific genome-scale metabolic model, while allowing for minor differences between chloroplast-containing organisms. The result of this work is the very first standardized chloroplast model, iGR774, consisting of 788 reactions, 764 metabolites, and 774 genes. The model is currently able to run in three different modes, mimicking the chloroplast metabolism of three photosynthetic microalgae-Nannochloropsis gaditana, Chlamydomonas reinhardtii and Phaeodactylum tricornutum. In addition to developing the chloroplast metabolic network reconstruction, we have developed multiple software tools for working with this novel type of sub-model in the COBRA Toolbox for MATLAB, including tools for connecting the chloroplast model to a genome-scale metabolic reconstruction in need of a chloroplast, for switching the model between running in different organism modes, and for expanding it by introducing more reactions either related to one of the current organisms included in the model, or to a new organism.
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Affiliation(s)
- Gunvor Bjerkelund Røkke
- Department of Biotechnology and Food Science, The Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Eivind Almaas
- Department of Biotechnology and Food Science, The Norwegian University of Science and Technology, Trondheim, Norway
- K. G. Jebsen Center for Genetic Epidemiology, The Norwegian University of Science and Technology, Trondheim, Norway
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Lavoie M, Saint-Béat B, Strauss J, Guérin S, Allard A, V. Hardy S, Falciatore A, Lavaud J. Genome-Scale Metabolic Reconstruction and in Silico Perturbation Analysis of the Polar Diatom Fragilariopsis cylindrus Predicts High Metabolic Robustness. BIOLOGY 2020; 9:biology9020030. [PMID: 32079178 PMCID: PMC7168318 DOI: 10.3390/biology9020030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 01/31/2020] [Accepted: 02/08/2020] [Indexed: 12/15/2022]
Abstract
Diatoms are major primary producers in polar environments where they can actively grow under extremely variable conditions. Integrative modeling using a genome-scale model (GSM) is a powerful approach to decipher the complex interactions between components of diatom metabolism and can provide insights into metabolic mechanisms underlying their evolutionary success in polar ecosystems. We developed the first GSM for a polar diatom, Fragilariopsis cylindrus, which enabled us to study its metabolic robustness using sensitivity analysis. We find that the predicted growth rate was robust to changes in all model parameters (i.e., cell biochemical composition) except the carbon uptake rate. Constraints on total cellular carbon buffer the effect of changes in the input parameters on reaction fluxes and growth rate. We also show that single reaction deletion of 20% to 32% of active (nonzero flux) reactions and single gene deletion of 44% to 55% of genes associated with active reactions affected the growth rate, as well as the production fluxes of total protein, lipid, carbohydrate, DNA, RNA, and pigments by less than 1%, which was due to the activation of compensatory reactions (e.g., analogous enzymes and alternative pathways) with more highly connected metabolites involved in the reactions that were robust to deletion. Interestingly, including highly divergent alleles unique for F. cylindrus increased its metabolic robustness to cellular perturbations even more. Overall, our results underscore the high robustness of metabolism in F. cylindrus, a feature that likely helps to maintain cell homeostasis under polar conditions.
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Affiliation(s)
- Michel Lavoie
- Unité Mixte Internationale 3376 Takuvik, CNRS-ULaval, Département de Biologie and Québec-Océan, Université Laval, Québec, QC G1V 0A6, Canada; (B.S.-B.); (S.G.); (J.L.)
- Correspondence:
| | - Blanche Saint-Béat
- Unité Mixte Internationale 3376 Takuvik, CNRS-ULaval, Département de Biologie and Québec-Océan, Université Laval, Québec, QC G1V 0A6, Canada; (B.S.-B.); (S.G.); (J.L.)
| | - Jan Strauss
- Department of Biology, University of Hamburg, D-22607 Hamburg, Germany;
- CSSB Centre for Structural Systems Biology, c/o Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607 Hamburg, Germany
| | - Sébastien Guérin
- Unité Mixte Internationale 3376 Takuvik, CNRS-ULaval, Département de Biologie and Québec-Océan, Université Laval, Québec, QC G1V 0A6, Canada; (B.S.-B.); (S.G.); (J.L.)
| | - Antoine Allard
- Département de physique, de génie physique et d’optique, Université Laval, Québec, QC G1V 0A6, Canada;
- Centre interdisciplinaire de modélisation mathématique, Université Laval, Québec, QC G1V 0A6, Canada
| | - Simon V. Hardy
- Département d’informatique et génie logiciel, Département de biochimie, microbiologie et bio-informatique, Université Laval, Québec, QC G1V 0A6, Canada;
- Unité des Neurosciences cellulaires et moléculaires, Centre de recherche CERVO, Québec, QC G1V 0A6, Canada
| | - Angela Falciatore
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141, Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, France;
| | - Johann Lavaud
- Unité Mixte Internationale 3376 Takuvik, CNRS-ULaval, Département de Biologie and Québec-Océan, Université Laval, Québec, QC G1V 0A6, Canada; (B.S.-B.); (S.G.); (J.L.)
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Butler T, Kapoore RV, Vaidyanathan S. Phaeodactylum tricornutum: A Diatom Cell Factory. Trends Biotechnol 2020; 38:606-622. [PMID: 31980300 DOI: 10.1016/j.tibtech.2019.12.023] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 01/12/2023]
Abstract
A switch from a petroleum-based to a biobased economy requires the capacity to produce both high-value low-volume and low-value high-volume products. Recent evidence supports the development of microalgae-based microbial cell factories with the objective of establishing environmentally sustainable manufacturing solutions. Diatoms display rich diversity and potential in this regard. We focus on Phaeodactylum tricornutum, a pennate diatom that is commonly found in marine ecosystems, and discuss recent trends in developing the diatom chassis for the production of a suite of natural and genetically engineered products. Both upstream and downstream developments are reviewed for the commercial development of P. tricornutum as a cell factory for a spectrum of marketable products.
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Affiliation(s)
- Thomas Butler
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield, S1 3JD, UK
| | - Rahul Vijay Kapoore
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield, S1 3JD, UK; Present address: Department of Biosciences, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - Seetharaman Vaidyanathan
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield, S1 3JD, UK.
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Pan Y, Hu F, Yu C, Li C, Huang T, Hu H. Amino Acid Catabolism During Nitrogen Limitation in Phaeodactylum tricornutum. FRONTIERS IN PLANT SCIENCE 2020; 11:589026. [PMID: 33408729 PMCID: PMC7780933 DOI: 10.3389/fpls.2020.589026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/23/2020] [Indexed: 05/08/2023]
Abstract
Diatoms can accumulate high levels of triacylglycerols (TAGs) under nitrogen depletion and have attracted increasing attention as a potential system for biofuel production. In Phaeodactylum tricornutum, a model diatom, about 40% of lipid is synthesized from the breakdown of cellular components under nitrogen starvation. Our previous studies indicated that carbon skeletons from enhanced branched-chain amino acid (BCAA) degradation under nitrogen deficiency contribute to TAG biosynthesis in P. tricornutum. In this review, we outlined the catabolic pathways of all 20 amino acids based on the genome, transcriptome, proteome, and metabolome data. The contribution of these amino acid catabolic pathways to TAG accumulation was also analyzed.
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Affiliation(s)
- Yufang Pan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Fan Hu
- School of Foreign Languages, China University of Geosciences, Wuhan, China
| | - Chen Yu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chenjie Li
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Teng Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hanhua Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- *Correspondence: Hanhua Hu,
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Ait-Mohamed O, Novák Vanclová AMG, Joli N, Liang Y, Zhao X, Genovesio A, Tirichine L, Bowler C, Dorrell RG. PhaeoNet: A Holistic RNAseq-Based Portrait of Transcriptional Coordination in the Model Diatom Phaeodactylum tricornutum. FRONTIERS IN PLANT SCIENCE 2020; 11:590949. [PMID: 33178253 PMCID: PMC7596299 DOI: 10.3389/fpls.2020.590949] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/15/2020] [Indexed: 05/04/2023]
Abstract
Transcriptional coordination is a fundamental component of prokaryotic and eukaryotic cell biology, underpinning the cell cycle, physiological transitions, and facilitating holistic responses to environmental stress, but its overall dynamics in eukaryotic algae remain poorly understood. Better understanding of transcriptional partitioning may provide key insights into the primary metabolism pathways of eukaryotic algae, which frequently depend on intricate metabolic associations between the chloroplasts and mitochondria that are not found in plants. Here, we exploit 187 publically available RNAseq datasets generated under varying nitrogen, iron and phosphate growth conditions to understand the co-regulatory principles underpinning transcription in the model diatom Phaeodactylum tricornutum. Using WGCNA (Weighted Gene Correlation Network Analysis), we identify 28 merged modules of co-expressed genes in the P. tricornutum genome, which show high connectivity and correlate well with previous microarray-based surveys of gene co-regulation in this species. We use combined functional, subcellular localization and evolutionary annotations to reveal the fundamental principles underpinning the transcriptional co-regulation of genes implicated in P. tricornutum chloroplast and mitochondrial metabolism, as well as the functions of diverse transcription factors underpinning this co-regulation. The resource is publically available as PhaeoNet, an advanced tool to understand diatom gene co-regulation.
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Affiliation(s)
- Ouardia Ait-Mohamed
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Anna M. G. Novák Vanclová
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Nathalie Joli
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Yue Liang
- Department of Oceanography, Dalhousie University, Halifax, NS, Canada
| | - Xue Zhao
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- Université de Nantes, CNRS, UFIP, UMR 6286, Nantes, France
| | - Auguste Genovesio
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Leila Tirichine
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- Université de Nantes, CNRS, UFIP, UMR 6286, Nantes, France
- *Correspondence: Leila Tirichine,
| | - Chris Bowler
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- Chris Bowler,
| | - Richard G. Dorrell
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
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Yi Z, Su Y, Cherek P, Nelson DR, Lin J, Rolfsson O, Wu H, Salehi-Ashtiani K, Brynjolfsson S, Fu W. Combined artificial high-silicate medium and LED illumination promote carotenoid accumulation in the marine diatom Phaeodactylum tricornutum. Microb Cell Fact 2019; 18:209. [PMID: 31791335 PMCID: PMC6889666 DOI: 10.1186/s12934-019-1263-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/28/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Diatoms, which can accumulate large amounts of carotenoids, are a major group of microalgae and the dominant primary producer in marine environments. Phaeodactylum tricornutum, a model diatom species, acquires little silicon for its growth although silicon is known to contribute to gene regulation and play an important role in diatom intracellular metabolism. In this study, we explored the effects of artificial high-silicate medium (i.e. 3.0 mM sodium metasilicate) and LED illumination conditions on the growth rate and pigment accumulation in P. tricornutum, which is the only known species so far that can grow without silicate. It's well known that light-emitting diodes (LEDs) as novel illuminants are emerging to be superior monochromatic light sources for algal cultivation with defined and efficient red and blue lights. RESULTS Firstly, we cultivated P. tricornutum in a synthetic medium supplemented with either 0.3 mM or 3.0 mM silicate. The morphology and size of diatom cells were examined: the proportion of the oval and triradiate cells decreased while the fusiform cells increased with more silicate addition in high-silicate medium; the average length of fusiform cells also slightly changed from 14.33 µm in 0.3 mM silicate medium to 12.20 µm in 3.0 mM silicate medium. Then we cultivated P. tricornutum under various intensities of red light in combination with the two different levels of silicate in the medium. Higher biomass productivity also achieved in 3.0 mM silicate medium than in 0.3 mM silicate medium under red LED light irradiation at 128 μmol/m2/s or higher light intensity. Increasing silicate reversed the down-regulation of fucoxanthin and chlorophyll a under high red-light illumination (i.e. 255 μmol/m2/s). When doubling the light intensity, fucoxanthin content decreased under red light but increased under combined red and blue (50:50) lights while chlorophyll a content reduced under both conditions. Fucoxanthin accumulation and biomass productivity increased with enhanced red and blue (50:50) lights. CONCLUSION High-silicate medium and blue light increased biomass and fucoxanthin production in P. tricornutum under high light conditions and this strategy may be beneficial for large-scale production of fucoxanthin in diatoms.
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Affiliation(s)
- Zhiqian Yi
- Center for Systems Biology and Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, Reykjavík, 101, Iceland.,Department of Orthopaedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.,Biomedical Center and Department of Anatomy, Faulty of Medicine, University of Iceland, Reykjavík, 101, Iceland
| | - Yixi Su
- Center for Systems Biology and Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, Reykjavík, 101, Iceland
| | - Paulina Cherek
- Biomedical Center and Department of Anatomy, Faulty of Medicine, University of Iceland, Reykjavík, 101, Iceland
| | - David R Nelson
- Center for Genomics and Systems Biology and Division of Science and Math, New York University Abu Dhabi, 129188, Abu Dhabi, United Arab Emirates
| | - Jianping Lin
- Key Laboratory of Biomass Chemical Engineering of the Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Ottar Rolfsson
- Center for Systems Biology and Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, Reykjavík, 101, Iceland
| | - Hua Wu
- Department of Orthopaedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Kourosh Salehi-Ashtiani
- Center for Genomics and Systems Biology and Division of Science and Math, New York University Abu Dhabi, 129188, Abu Dhabi, United Arab Emirates
| | - Sigurdur Brynjolfsson
- Center for Systems Biology and Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, Reykjavík, 101, Iceland
| | - Weiqi Fu
- Center for Systems Biology and Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, Reykjavík, 101, Iceland. .,Center for Genomics and Systems Biology and Division of Science and Math, New York University Abu Dhabi, 129188, Abu Dhabi, United Arab Emirates.
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Evolution and regulation of nitrogen flux through compartmentalized metabolic networks in a marine diatom. Nat Commun 2019; 10:4552. [PMID: 31591397 PMCID: PMC6779911 DOI: 10.1038/s41467-019-12407-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 09/03/2019] [Indexed: 01/15/2023] Open
Abstract
Diatoms outcompete other phytoplankton for nitrate, yet little is known about the mechanisms underpinning this ability. Genomes and genome-enabled studies have shown that diatoms possess unique features of nitrogen metabolism however, the implications for nutrient utilization and growth are poorly understood. Using a combination of transcriptomics, proteomics, metabolomics, fluxomics, and flux balance analysis to examine short-term shifts in nitrogen utilization in the model pennate diatom in Phaeodactylum tricornutum, we obtained a systems-level understanding of assimilation and intracellular distribution of nitrogen. Chloroplasts and mitochondria are energetically integrated at the critical intersection of carbon and nitrogen metabolism in diatoms. Pathways involved in this integration are organelle-localized GS-GOGAT cycles, aspartate and alanine systems for amino moiety exchange, and a split-organelle arginine biosynthesis pathway that clarifies the role of the diatom urea cycle. This unique configuration allows diatoms to efficiently adjust to changing nitrogen status, conferring an ecological advantage over other phytoplankton taxa. Here, using the diatom Phaeodactylum tricornutum as a model organism, the authors combine functional genomics, phylogenetics, and metabolic modeling to describe how diatoms might have functionally integrated nitrogen metabolism during evolution and how metabolic flux is regulated across cellular compartments
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Goldman JAL, Schatz MJ, Berthiaume CT, Coesel SN, Orellana MV, Armbrust EV. Fe limitation decreases transcriptional regulation over the diel cycle in the model diatom Thalassiosira pseudonana. PLoS One 2019; 14:e0222325. [PMID: 31509589 PMCID: PMC6738920 DOI: 10.1371/journal.pone.0222325] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 08/27/2019] [Indexed: 01/02/2023] Open
Abstract
Iron (Fe) is an important growth factor for diatoms and its availability is further restricted by changes in the carbonate chemistry of seawater. We investigated the physiological attributes and transcriptional profiles of the diatom Thalassiosira pseudonana grown on a day: night cycle under different CO2/pH and iron concentrations, that in combination generated available iron (Fe') concentrations of 1160, 233, 58 and 12 pM. We found the light-dark conditions to be the main driver of transcriptional patterns, followed by Fe' concentration and CO2 availability, respectively. At the highest Fe' (1160 pM), 55% of the transcribed genes were differentially expressed between day and night, whereas at the lowest Fe' (12 pM), only 28% of the transcribed genes displayed comparable patterns. While Fe limitation disrupts the diel expression patterns for genes in most central metabolism pathways, the diel expression of light- signaling molecules and glycolytic genes was relatively robust in response to reduced Fe'. Moreover, we identified a non-canonical splicing of transcripts encoding triose-phosphate isomerase, a key-enzyme of glycolysis, generating transcript isoforms that would encode proteins with and without an active site. Transcripts that encoded an active enzyme maintained a diel expression at low Fe', while transcripts that encoded the non-active enzyme lost the diel expression. This work illustrates the interplay between nutrient limitation and transcriptional regulation over the diel cycle. Considering that future ocean conditions will reduce the availability of Fe in many parts of the oceans, our work identifies some of the regulatory mechanisms that may shape future ecological communities.
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Affiliation(s)
- Johanna A. L. Goldman
- School of Oceanography, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Megan J. Schatz
- School of Oceanography, University of Washington, Seattle, Washington, United States of America
| | - Chris T. Berthiaume
- School of Oceanography, University of Washington, Seattle, Washington, United States of America
| | - Sacha N. Coesel
- School of Oceanography, University of Washington, Seattle, Washington, United States of America
| | - Mónica V. Orellana
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, Washington, United States of America
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - E. Virginia Armbrust
- School of Oceanography, University of Washington, Seattle, Washington, United States of America
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Metabolic Innovations Underpinning the Origin and Diversification of the Diatom Chloroplast. Biomolecules 2019; 9:biom9080322. [PMID: 31366180 PMCID: PMC6723447 DOI: 10.3390/biom9080322] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 12/13/2022] Open
Abstract
Of all the eukaryotic algal groups, diatoms make the most substantial contributions to photosynthesis in the contemporary ocean. Understanding the biological innovations that have occurred in the diatom chloroplast may provide us with explanations to the ecological success of this lineage and clues as to how best to exploit the biology of these organisms for biotechnology. In this paper, we use multi-species transcriptome datasets to compare chloroplast metabolism pathways in diatoms to other algal lineages. We identify possible diatom-specific innovations in chloroplast metabolism, including the completion of tocopherol synthesis via a chloroplast-targeted tocopherol cyclase, a complete chloroplast ornithine cycle, and chloroplast-targeted proteins involved in iron acquisition and CO2 concentration not shared between diatoms and their closest relatives in the stramenopiles. We additionally present a detailed investigation of the chloroplast metabolism of the oil-producing diatom Fistulifera solaris, which is of industrial interest for biofuel production. These include modified amino acid and pyruvate hub metabolism that might enhance acetyl-coA production for chloroplast lipid biosynthesis and the presence of a chloroplast-localised squalene synthesis pathway unknown in other diatoms. Our data provides valuable insights into the biological adaptations underpinning an ecologically critical lineage, and how chloroplast metabolism can change even at a species level in extant algae.
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Fu W, Nelson DR, Mystikou A, Daakour S, Salehi-Ashtiani K. Advances in microalgal research and engineering development. Curr Opin Biotechnol 2019; 59:157-164. [PMID: 31252302 DOI: 10.1016/j.copbio.2019.05.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 05/17/2019] [Accepted: 05/22/2019] [Indexed: 02/07/2023]
Abstract
Microalgae have been investigated for the photosynthetic production of natural products with industrial and biomedical applications. Their rapid growth offers an advantage over higher plants, while their complex metabolic capacities allow for the production of various molecules. Despite their potentials, molecular techniques are underdeveloped in microalgae compared to higher plants, fungi, and bacteria. However, recent advances in genome sequencing, strain development, and genome editing technologies, are providing thrust to enhance research on microalgal species that have branched out from several focal model organisms to encompass a great diversity of species. In this review, we highlight the recent, significant advances in microalgal research, with a focus on the development of new resources that can enhance work on model and non-model species.
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Affiliation(s)
- Weiqi Fu
- Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates; Center for Systems Biology and Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, 101 Reykjavík, Iceland
| | - David R Nelson
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Alexandra Mystikou
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Sarah Daakour
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Kourosh Salehi-Ashtiani
- Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates; Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
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Broddrick JT, Du N, Smith SR, Tsuji Y, Jallet D, Ware MA, Peers G, Matsuda Y, Dupont CL, Mitchell BG, Palsson BO, Allen AE. Cross-compartment metabolic coupling enables flexible photoprotective mechanisms in the diatom Phaeodactylum tricornutum. THE NEW PHYTOLOGIST 2019; 222:1364-1379. [PMID: 30636322 PMCID: PMC6594073 DOI: 10.1111/nph.15685] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 12/20/2018] [Indexed: 05/07/2023]
Abstract
Photoacclimation consists of short- and long-term strategies used by photosynthetic organisms to adapt to dynamic light environments. Observable photophysiology changes resulting from these strategies have been used in coarse-grained models to predict light-dependent growth and photosynthetic rates. However, the contribution of the broader metabolic network, relevant to species-specific strategies and fitness, is not accounted for in these simple models. We incorporated photophysiology experimental data with genome-scale modeling to characterize organism-level, light-dependent metabolic changes in the model diatom Phaeodactylum tricornutum. Oxygen evolution and photon absorption rates were combined with condition-specific biomass compositions to predict metabolic pathway usage for cells acclimated to four different light intensities. Photorespiration, an ornithine-glutamine shunt, and branched-chain amino acid metabolism were hypothesized as the primary intercompartment reductant shuttles for mediating excess light energy dissipation. Additionally, simulations suggested that carbon shunted through photorespiration is recycled back to the chloroplast as pyruvate, a mechanism distinct from known strategies in photosynthetic organisms. Our results suggest a flexible metabolic network in P. tricornutum that tunes intercompartment metabolism to optimize energy transport between the organelles, consuming excess energy as needed. Characterization of these intercompartment reductant shuttles broadens our understanding of energy partitioning strategies in this clade of ecologically important primary producers.
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Affiliation(s)
- Jared T. Broddrick
- Division of Biological SciencesUC San DiegoLa JollaCA92093USA
- Department of BioengineeringUC San DiegoLa JollaCA92093USA
| | - Niu Du
- Scripps Institution of OceanographyUC San DiegoLa JollaCA92093USA
- J. Craig Venter InstituteLa JollaCA92037USA
| | | | - Yoshinori Tsuji
- Department of Environmental BioscienceKwansei Gakuin UniversitySanda669‐1337Japan
| | - Denis Jallet
- Department of BiologyColorado State UniversityFort CollinsCO80523USA
| | - Maxwell A. Ware
- Department of BiologyColorado State UniversityFort CollinsCO80523USA
| | - Graham Peers
- Department of BiologyColorado State UniversityFort CollinsCO80523USA
| | - Yusuke Matsuda
- Department of Environmental BioscienceKwansei Gakuin UniversitySanda669‐1337Japan
| | | | - B. Greg Mitchell
- Scripps Institution of OceanographyUC San DiegoLa JollaCA92093USA
| | | | - Andrew E. Allen
- Scripps Institution of OceanographyUC San DiegoLa JollaCA92093USA
- J. Craig Venter InstituteLa JollaCA92037USA
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41
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A synthetic ecosystem for the multi-level modelling of heterotroph-phototroph metabolic interactions. Ecol Modell 2019. [DOI: 10.1016/j.ecolmodel.2019.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Vavitsas K, Fabris M, Vickers CE. Terpenoid Metabolic Engineering in Photosynthetic Microorganisms. Genes (Basel) 2018; 9:E520. [PMID: 30360565 PMCID: PMC6266707 DOI: 10.3390/genes9110520] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 12/13/2022] Open
Abstract
Terpenoids are a group of natural products that have a variety of roles, both essential and non-essential, in metabolism and in biotic and abiotic interactions, as well as commercial applications such as pharmaceuticals, food additives, and chemical feedstocks. Economic viability for commercial applications is commonly not achievable by using natural source organisms or chemical synthesis. Engineered bio-production in suitable heterologous hosts is often required to achieve commercial viability. However, our poor understanding of regulatory mechanisms and other biochemical processes makes obtaining efficient conversion yields from feedstocks challenging. Moreover, production from carbon dioxide via photosynthesis would significantly increase the environmental and potentially the economic credentials of these processes by disintermediating biomass feedstocks. In this paper, we briefly review terpenoid metabolism, outline some recent advances in terpenoid metabolic engineering, and discuss why photosynthetic unicellular organisms-such as algae and cyanobacteria-might be preferred production platforms for the expression of some of the more challenging terpenoid pathways.
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Affiliation(s)
- Konstantinos Vavitsas
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia.
- CSIRO Synthetic Biology Future Science Platform, GPO Box 2583, Brisbane, QLD 4001, Australia.
| | - Michele Fabris
- Climate Change Cluster, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007, Australia.
- CSIRO Synthetic Biology Future Science Platform, GPO Box 2583, Brisbane, QLD 4001, Australia.
| | - Claudia E Vickers
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia.
- CSIRO Synthetic Biology Future Science Platform, GPO Box 2583, Brisbane, QLD 4001, Australia.
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Wang H, Marcišauskas S, Sánchez BJ, Domenzain I, Hermansson D, Agren R, Nielsen J, Kerkhoven EJ. RAVEN 2.0: A versatile toolbox for metabolic network reconstruction and a case study on Streptomyces coelicolor. PLoS Comput Biol 2018; 14:e1006541. [PMID: 30335785 PMCID: PMC6207324 DOI: 10.1371/journal.pcbi.1006541] [Citation(s) in RCA: 153] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/30/2018] [Accepted: 10/02/2018] [Indexed: 12/22/2022] Open
Abstract
RAVEN is a commonly used MATLAB toolbox for genome-scale metabolic model (GEM) reconstruction, curation and constraint-based modelling and simulation. Here we present RAVEN Toolbox 2.0 with major enhancements, including: (i) de novo reconstruction of GEMs based on the MetaCyc pathway database; (ii) a redesigned KEGG-based reconstruction pipeline; (iii) convergence of reconstructions from various sources; (iv) improved performance, usability, and compatibility with the COBRA Toolbox. Capabilities of RAVEN 2.0 are here illustrated through de novo reconstruction of GEMs for the antibiotic-producing bacterium Streptomyces coelicolor. Comparison of the automated de novo reconstructions with the iMK1208 model, a previously published high-quality S. coelicolor GEM, exemplifies that RAVEN 2.0 can capture most of the manually curated model. The generated de novo reconstruction is subsequently used to curate iMK1208 resulting in Sco4, the most comprehensive GEM of S. coelicolor, with increased coverage of both primary and secondary metabolism. This increased coverage allows the use of Sco4 to predict novel genome editing targets for optimized secondary metabolites production. As such, we demonstrate that RAVEN 2.0 can be used not only for de novo GEM reconstruction, but also for curating existing models based on up-to-date databases. Both RAVEN 2.0 and Sco4 are distributed through GitHub to facilitate usage and further development by the community (https://github.com/SysBioChalmers/RAVEN and https://github.com/SysBioChalmers/Streptomyces_coelicolor-GEM).
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Affiliation(s)
- Hao Wang
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Simonas Marcišauskas
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Benjamín J. Sánchez
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Iván Domenzain
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Daniel Hermansson
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Rasmus Agren
- Department of Biology and Biological Engineering, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Chalmers University of Technology, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Eduard J. Kerkhoven
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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44
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Tibocha-Bonilla JD, Zuñiga C, Godoy-Silva RD, Zengler K. Advances in metabolic modeling of oleaginous microalgae. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:241. [PMID: 30202436 PMCID: PMC6124020 DOI: 10.1186/s13068-018-1244-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/27/2018] [Indexed: 06/08/2023]
Abstract
Production of biofuels and bioenergy precursors by phototrophic microorganisms, such as microalgae and cyanobacteria, is a promising alternative to conventional fuels obtained from non-renewable resources. Several species of microalgae have been investigated as potential candidates for the production of biofuels, for the most part due to their exceptional metabolic capability to accumulate large quantities of lipids. Constraint-based modeling, a systems biology approach that accurately predicts the metabolic phenotype of phototrophs, has been deployed to identify suitable culture conditions as well as to explore genetic enhancement strategies for bioproduction. Core metabolic models were employed to gain insight into the central carbon metabolism in photosynthetic microorganisms. More recently, comprehensive genome-scale models, including organelle-specific information at high resolution, have been developed to gain new insight into the metabolism of phototrophic cell factories. Here, we review the current state of the art of constraint-based modeling and computational method development and discuss how advanced models led to increased prediction accuracy and thus improved lipid production in microalgae.
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Affiliation(s)
- Juan D. Tibocha-Bonilla
- Grupo de Investigación en Procesos Químicos y Bioquímicos, Departamento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Av. Carrera 30 No. 45-03, Bogotá, D.C. Colombia
| | - Cristal Zuñiga
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760 USA
| | - Rubén D. Godoy-Silva
- Grupo de Investigación en Procesos Químicos y Bioquímicos, Departamento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Av. Carrera 30 No. 45-03, Bogotá, D.C. Colombia
| | - Karsten Zengler
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760 USA
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412 USA
- Center for Microbiome Innovation, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0436 USA
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45
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Chemical Mutagenesis and Fluorescence-Based High-Throughput Screening for Enhanced Accumulation of Carotenoids in a Model Marine Diatom Phaeodactylum tricornutum. Mar Drugs 2018; 16:md16080272. [PMID: 30081564 PMCID: PMC6117690 DOI: 10.3390/md16080272] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 07/20/2018] [Accepted: 08/02/2018] [Indexed: 01/11/2023] Open
Abstract
Diatoms are a major group of unicellular algae that are rich in lipids and carotenoids. However, sustained research efforts are needed to improve the strain performance for high product yields towards commercialization. In this study, we generated a number of mutants of the model diatom Phaeodactylum tricornutum, a cosmopolitan species that has also been found in Nordic region, using the chemical mutagens ethyl methanesulfonate (EMS) and N-methyl-N′-nitro-N-nitrosoguanidine (NTG). We found that both chlorophyll a and neutral lipids had a significant correlation with carotenoid content and these correlations were better during exponential growth than in the stationary growth phase. Then, we studied P. tricornutum common metabolic pathways and analyzed correlated enzymatic reactions between fucoxanthin synthesis and pigmentation or lipid metabolism through a genome-scale metabolic model. The integration of the computational results with liquid chromatography-mass spectrometry data revealed key compounds underlying the correlative metabolic pathways. Approximately 1000 strains were screened using fluorescence-based high-throughput method and five mutants selected had 33% or higher total carotenoids than the wild type, in which four strains remained stable in the long term and the top mutant exhibited an increase of 69.3% in fucoxanthin content compared to the wild type. The platform described in this study may be applied to the screening of other high performing diatom strains for industrial applications.
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46
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Rodenburg SYA, Seidl MF, de Ridder D, Govers F. Genome-wide characterization of Phytophthora infestans metabolism: a systems biology approach. MOLECULAR PLANT PATHOLOGY 2018; 19:1403-1413. [PMID: 28990716 PMCID: PMC6638193 DOI: 10.1111/mpp.12623] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/23/2017] [Accepted: 10/04/2017] [Indexed: 05/18/2023]
Abstract
Genome-scale metabolic models (GEMs) provide a functional view of the complex network of biochemical reactions in the living cell. Initially mainly applied to reconstruct the metabolism of model organisms, the availability of increasingly sophisticated reconstruction methods and more extensive biochemical databases now make it possible to reconstruct GEMs for less well-characterized organisms, and have the potential to unravel the metabolism in pathogen-host systems. Here, we present a GEM for the oomycete plant pathogen Phytophthora infestans as a first step towards an integrative model with its host. We predict the biochemical reactions in different cellular compartments and investigate the gene-protein-reaction associations in this model to obtain an impression of the biochemical capabilities of P. infestans. Furthermore, we generate life stage-specific models to place the transcriptomic changes of the genes encoding metabolic enzymes into a functional context. In sporangia and zoospores, there is an overall down-regulation, most strikingly reflected in the fatty acid biosynthesis pathway. To investigate the robustness of the GEM, we simulate gene deletions to predict which enzymes are essential for in vitro growth. This model is an essential first step towards an understanding of P. infestans and its interactions with plants as a system, which will help to formulate new hypotheses on infection mechanisms and disease prevention.
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Affiliation(s)
- Sander Y. A. Rodenburg
- Laboratory of PhytopathologyWageningen University, Wageningen 6708 PBthe Netherlands
- Bioinformatics GroupWageningen University, Wageningen 6708 PBthe Netherlands
| | - Michael F. Seidl
- Laboratory of PhytopathologyWageningen University, Wageningen 6708 PBthe Netherlands
| | - Dick de Ridder
- Bioinformatics GroupWageningen University, Wageningen 6708 PBthe Netherlands
| | - Francine Govers
- Laboratory of PhytopathologyWageningen University, Wageningen 6708 PBthe Netherlands
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47
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Maeda Y, Nojima D, Yoshino T, Tanaka T. Structure and properties of oil bodies in diatoms. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0408. [PMID: 28717018 DOI: 10.1098/rstb.2016.0408] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2017] [Indexed: 01/23/2023] Open
Abstract
Diatoms accumulate triacylglycerols in spherical organelles called oil bodies when exposed to nutrient deprivation conditions. Oil body biology in diatoms has attracted significant attention due to the complexity of the intracellular organelles and the unique combination of genes generated by the evolutionary history of secondary endosymbiosis. The demand for biofuel production has further increased the interest in and importance of a better understanding of oil body biology in diatoms, because it could provide targets for genetic engineering to further enhance their promising lipid accumulation. This review describes recent progress in studies of the structure and properties of diatom oil bodies. Firstly, the general features of diatom oil bodies are described, in particular, their number, size and morphology, as well as the quantity and quality of lipids they contain. Subsequently, the diatom oil body-associated proteins, which were recently discovered through oil body proteomics, are introduced. Then, the metabolic pathways responsible for the biogenesis and degradation of diatom oil bodies are summarized. During biogenesis and degradation, oil bodies interact with other organelles, including chloroplasts, the endoplasmic reticulum and mitochondria, suggesting their dynamic nature in response to environmental changes. Finally, the functions of oil bodies in diatoms are discussed.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.
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Affiliation(s)
- Yoshiaki Maeda
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Daisuke Nojima
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Tomoko Yoshino
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Tsuyoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
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48
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Wagner H, Jakob T, Fanesi A, Wilhelm C. Towards an understanding of the molecular regulation of carbon allocation in diatoms: the interaction of energy and carbon allocation. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0410. [PMID: 28717020 DOI: 10.1098/rstb.2016.0410] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2017] [Indexed: 11/12/2022] Open
Abstract
In microalgae, the photosynthesis-driven CO2 assimilation delivers cell building blocks that are used in different biosynthetic pathways. Little is known about how the cell regulates the subsequent carbon allocation to, for example, cell growth or for storage. However, knowledge about these regulatory mechanisms is of high biotechnological and ecological importance. In diatoms, the situation becomes even more complex because, as a consequence of their secondary endosymbiotic origin, the compartmentation of the pathways for the primary metabolic routes is different from green algae. Therefore, the mechanisms to manipulate the carbon allocation pattern cannot be adopted from the green lineage. This review describes the general pathways of cellular energy distribution from light absorption towards the final allocation of carbon into macromolecules and summarizes the current knowledge of diatom-specific allocation patterns. We further describe the (limited) knowledge of regulatory mechanisms of carbon partitioning between lipids, carbohydrates and proteins in diatoms. We present solutions to overcome the problems that hinder the identification of regulatory elements of carbon metabolism.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.
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Affiliation(s)
- Heiko Wagner
- Department of Plant Physiology, Leipzig University, Institute of Biology, Johannisallee 21-23, 04103 Leipzig, Germany
| | - Torsten Jakob
- Department of Plant Physiology, Leipzig University, Institute of Biology, Johannisallee 21-23, 04103 Leipzig, Germany
| | - Andrea Fanesi
- Department of Plant Physiology, Leipzig University, Institute of Biology, Johannisallee 21-23, 04103 Leipzig, Germany
| | - Christian Wilhelm
- Department of Plant Physiology, Leipzig University, Institute of Biology, Johannisallee 21-23, 04103 Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany
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49
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Zuñiga C, Levering J, Antoniewicz MR, Guarnieri MT, Betenbaugh MJ, Zengler K. Predicting Dynamic Metabolic Demands in the Photosynthetic Eukaryote Chlorella vulgaris. PLANT PHYSIOLOGY 2018; 176:450-462. [PMID: 28951490 PMCID: PMC5761767 DOI: 10.1104/pp.17.00605] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 09/21/2017] [Indexed: 06/02/2023]
Abstract
Phototrophic organisms exhibit a highly dynamic proteome, adapting their biomass composition in response to diurnal light/dark cycles and nutrient availability. Here, we used experimentally determined biomass compositions over the course of growth to determine and constrain the biomass objective function (BOF) in a genome-scale metabolic model of Chlorella vulgaris UTEX 395 over time. Changes in the BOF, which encompasses all metabolites necessary to produce biomass, influence the state of the metabolic network thus directly affecting predictions. Simulations using dynamic BOFs predicted distinct proteome demands during heterotrophic or photoautotrophic growth. Model-driven analysis of extracellular nitrogen concentrations and predicted nitrogen uptake rates revealed an intracellular nitrogen pool, which contains 38% of the total nitrogen provided in the medium for photoautotrophic and 13% for heterotrophic growth. Agreement between flux and gene expression trends was determined by statistical comparison. Accordance between predicted flux trends and gene expression trends was found for 65% of multisubunit enzymes and 75% of allosteric reactions. Reactions with the highest agreement between simulations and experimental data were associated with energy metabolism, terpenoid biosynthesis, fatty acids, nucleotides, and amino acid metabolism. Furthermore, predicted flux distributions at each time point were compared with gene expression data to gain new insights into intracellular compartmentalization, specifically for transporters. A total of 103 genes related to internal transport reactions were identified and added to the updated model of C. vulgaris, iCZ946, thus increasing our knowledgebase by 10% for this model green alga.
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Affiliation(s)
- Cristal Zuñiga
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0760
| | - Jennifer Levering
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0760
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, 150 Academy Street, Newark, Delaware 19716
| | - Michael T Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Michael J Betenbaugh
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218
| | - Karsten Zengler
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0760
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50
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Zuñiga C, Zaramela L, Zengler K. Elucidation of complexity and prediction of interactions in microbial communities. Microb Biotechnol 2017; 10:1500-1522. [PMID: 28925555 PMCID: PMC5658597 DOI: 10.1111/1751-7915.12855] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/10/2017] [Accepted: 08/11/2017] [Indexed: 12/11/2022] Open
Abstract
Microorganisms engage in complex interactions with other members of the microbial community, higher organisms as well as their environment. However, determining the exact nature of these interactions can be challenging due to the large number of members in these communities and the manifold of interactions they can engage in. Various omic data, such as 16S rRNA gene sequencing, shotgun metagenomics, metatranscriptomics, metaproteomics and metabolomics, have been deployed to unravel the community structure, interactions and resulting community dynamics in situ. Interpretation of these multi-omic data often requires advanced computational methods. Modelling approaches are powerful tools to integrate, contextualize and interpret experimental data, thus shedding light on the underlying processes shaping the microbiome. Here, we review current methods and approaches, both experimental and computational, to elucidate interactions in microbial communities and to predict their responses to perturbations.
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Affiliation(s)
- Cristal Zuñiga
- Department of PediatricsUniversity of California, San Diego9500 Gilman DriveLa JollaCA92093‐0760USA
| | - Livia Zaramela
- Department of PediatricsUniversity of California, San Diego9500 Gilman DriveLa JollaCA92093‐0760USA
| | - Karsten Zengler
- Department of PediatricsUniversity of California, San Diego9500 Gilman DriveLa JollaCA92093‐0760USA
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