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Ischebeck T, Krawczyk HE, Mullen RT, Dyer JM, Chapman KD. Lipid droplets in plants and algae: Distribution, formation, turnover and function. Semin Cell Dev Biol 2020; 108:82-93. [PMID: 32147380 DOI: 10.1016/j.semcdb.2020.02.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/28/2020] [Accepted: 02/29/2020] [Indexed: 01/02/2023]
Abstract
Plant oils represent an energy-rich and carbon-dense group of hydrophobic compounds. These oils are not only of economic interest, but also play important, fundamental roles in plant and algal growth and development. The subcellular storage compartments of plant lipids, referred to as lipid droplets (LDs), have long been considered relatively inert oil vessels. However, research in the last decade has revealed that LDs play far more dynamic roles in plant biology than previously appreciated, including transient neutral lipid storage, membrane remodeling, lipid signaling, and stress responses. Here we discuss recent developments in the understanding of LD formation, turnover and function in land plants and algae.
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Affiliation(s)
- Till Ischebeck
- University of Göttingen, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences (GZMB), Department of Plant Biochemistry, 37077, Göttingen, Germany.
| | - Hannah E Krawczyk
- University of Göttingen, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences (GZMB), Department of Plant Biochemistry, 37077, Göttingen, Germany
| | - Robert T Mullen
- University of Guelph, Department of Molecular Cell Biology, Guelph, Ontario, N1G 2W1, Canada
| | - John M Dyer
- United States Department of Agriculture, Agriculture Research Service, US Arid-Land Agricultural Research Center, Maricopa, AZ, 85138, USA
| | - Kent D Chapman
- University of North Texas, BioDiscovery Institute, Department of Biological Sciences, Denton, TX, 76203, USA
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52
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Zienkiewicz K, Zienkiewicz A. Degradation of Lipid Droplets in Plants and Algae-Right Time, Many Paths, One Goal. FRONTIERS IN PLANT SCIENCE 2020; 11:579019. [PMID: 33014002 PMCID: PMC7509404 DOI: 10.3389/fpls.2020.579019] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/24/2020] [Indexed: 05/05/2023]
Abstract
In eukaryotic cells, lipids in the form of triacylglycerols (TAGs) are the major reservoir of cellular carbon and energy. These TAGs are packed into specialized organelles called lipid droplets (LDs). They can be found in most, if not all, types of cells, from bacteria to human. Recent data suggest that rather than being simple storage organelles, LDs are very dynamic structures at the center of cellular metabolism. This is also true in plants and algae, where LDs have been implicated in many processes including energy supply; membrane structure, function, trafficking; and signal transduction. Plant and algal LDs also play a vital role in human life, providing multiple sources of food and fuel. Thus, a lot of attention has been paid to metabolism and function of these organelles in recent years. This review summarizes the most recent advances on LDs degradation as a key process for TAGs release. While the initial knowledge on this process came from studies in oilseeds, the findings of the last decade revealed high complexity and specific mechanisms of LDs degradation in plants and algae. This includes identification of numerous novel proteins associated with LDs as well as a prominent role for autophagy in this process. This review outlines, systemizes, and discusses the most current data on LDs catabolism in plants and algae.
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53
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The Puzzling Conservation and Diversification of Lipid Droplets from Bacteria to Eukaryotes. Results Probl Cell Differ 2020; 69:281-334. [PMID: 33263877 DOI: 10.1007/978-3-030-51849-3_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Membrane compartments are amongst the most fascinating markers of cell evolution from prokaryotes to eukaryotes, some being conserved and the others having emerged via a series of primary and secondary endosymbiosis events. Membrane compartments comprise the system limiting cells (one or two membranes in bacteria, a unique plasma membrane in eukaryotes) and a variety of internal vesicular, subspherical, tubular, or reticulated organelles. In eukaryotes, the internal membranes comprise on the one hand the general endomembrane system, a dynamic network including organelles like the endoplasmic reticulum, the Golgi apparatus, the nuclear envelope, etc. and also the plasma membrane, which are linked via direct lateral connectivity (e.g. between the endoplasmic reticulum and the nuclear outer envelope membrane) or indirectly via vesicular trafficking. On the other hand, semi-autonomous organelles, i.e. mitochondria and chloroplasts, are disconnected from the endomembrane system and request vertical transmission following cell division. Membranes are organized as lipid bilayers in which proteins are embedded. The budding of some of these membranes, leading to the formation of the so-called lipid droplets (LDs) loaded with hydrophobic molecules, most notably triacylglycerol, is conserved in all clades. The evolution of eukaryotes is marked by the acquisition of mitochondria and simple plastids from Gram-positive bacteria by primary endosymbiosis events and the emergence of extremely complex plastids, collectively called secondary plastids, bounded by three to four membranes, following multiple and independent secondary endosymbiosis events. There is currently no consensus view of the evolution of LDs in the Tree of Life. Some features are conserved; others show a striking level of diversification. Here, we summarize the current knowledge on the architecture, dynamics, and multitude of functions of the lipid droplets in prokaryotes and in eukaryotes deriving from primary and secondary endosymbiosis events.
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Ran W, Wang H, Liu Y, Qi M, Xiang Q, Yao C, Zhang Y, Lan X. Storage of starch and lipids in microalgae: Biosynthesis and manipulation by nutrients. BIORESOURCE TECHNOLOGY 2019; 291:121894. [PMID: 31387839 DOI: 10.1016/j.biortech.2019.121894] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 05/28/2023]
Abstract
Microalgae accumulate starch and lipid as storage metabolites under nutrient depletion, which can be used as sustainable feedstock for biorefinery. Omics analysis coupled with enzymatic and genetic verifications uncovered a partial picture of pathways and important enzymes or regulators related to starch and lipid biosynthesis as well as the carbon partitioning between them under nutrient depletion conditions. Depletion of macronutrients (N, P, and S) resulted in considerable enhancement of starch and/or lipid content in microalgae, but the accompanying declined photosynthesis hampered the achievements of high concentrations. This review summarized the current knowledge on the pathways and the committed steps as well as their carbon allocation involved in starch and lipid biosynthesis, and focused on the manipulation of different nutrients and the alleviation of oxidative stress for enhanced storage metabolites production. The biological and engineering approaches to cope with the conflict between biomass production and storage metabolites accumulation are proposed.
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Affiliation(s)
- Wenyi Ran
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Haitao Wang
- National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, Liaoning 116034, China
| | - Yinghui Liu
- Information Management Center of Sichuan University, Chengdu, Sichuan 610065, China
| | - Man Qi
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Qi Xiang
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Changhong Yao
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Yongkui Zhang
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Xianqiu Lan
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
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Burlacot A, Peltier G, Li-Beisson Y. Subcellular Energetics and Carbon Storage in Chlamydomonas. Cells 2019; 8:E1154. [PMID: 31561610 PMCID: PMC6830334 DOI: 10.3390/cells8101154] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/19/2019] [Accepted: 09/24/2019] [Indexed: 01/09/2023] Open
Abstract
Microalgae have emerged as a promising platform for production of carbon- and energy- rich molecules, notably starch and oil. Establishing an economically viable algal biotechnology sector requires a holistic understanding of algal photosynthesis, physiology, cell cycle and metabolism. Starch/oil productivity is a combined effect of their cellular content and cell division activities. Cell growth, starch and fatty acid synthesis all require carbon building blocks and a source of energy in the form of ATP and NADPH, but with a different requirement in ATP/NADPH ratio. Thus, several cellular mechanisms have been developed by microalgae to balance ATP and NADPH supply which are essentially produced by photosynthesis. Major energy management mechanisms include ATP production by the chloroplast-based cyclic electron flow and NADPH removal by water-water cycles. Furthermore, energetic coupling between chloroplast and other cellular compartments, mitochondria and peroxisome, is increasingly recognized as an important process involved in the chloroplast redox poise. Emerging literature suggests that alterations of energy management pathways affect not only cell fitness and survival, but also influence biomass content and composition. These emerging discoveries are important steps towards diverting algal photosynthetic energy to useful products for biotechnological applications.
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Affiliation(s)
- Adrien Burlacot
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache CEDEX, 13108 Saint Paul-Lez-Durance, France.
| | - Gilles Peltier
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache CEDEX, 13108 Saint Paul-Lez-Durance, France.
| | - Yonghua Li-Beisson
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache CEDEX, 13108 Saint Paul-Lez-Durance, France.
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Warakanont J, Li-Beisson Y, Benning C. LIP4 Is Involved in Triacylglycerol Degradation in Chlamydomonas reinhardtii. PLANT & CELL PHYSIOLOGY 2019; 60:1250-1259. [PMID: 30796452 DOI: 10.1093/pcp/pcz037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/13/2019] [Indexed: 05/03/2023]
Abstract
Degradation of the storage compound triacylglycerol (TAG) is a crucial process in response to environmental stimuli. In microalgae, this process is important for re-growth when conditions become favorable after cells have experienced stresses. Mobilization of TAG is initiated by actions of lipases causing the release of glycerol and free fatty acids, which can be further broken down for energy production or recycled to synthesize membrane lipids. Although key enzymes in the process, TAG lipases remain to be characterized in the model green alga Chlamydomonas reinhardtii. Here, we describe the functional analysis of a putative TAG lipase, i.e. LIP4, which shares 44% amino acid identity with the major TAG lipase in Arabidopsis (SUGAR DEPENDENT1-SDP1). The LIP4 transcript level was downregulated during nitrogen deprivation when TAG accumulates, but was upregulated during nitrogen resupply (NR) when TAG was degraded. Both artificial microRNA and insertional mutants showed a delay in TAG mobilization during NR. The difference in TAG degradation was more pronounced when the cultures were incubated without acetate in the dark. Furthermore, the lip4 insertional mutants over-accumulated TAG during optimal growth conditions. Taken together, the results suggest to us that LIP4 likely acts as a TAG lipase and plays a role in TAG homeostasis in Chlamydomonas.
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Affiliation(s)
- Jaruswan Warakanont
- Department of Botany, Faculty of Science, Kasetsart University, 50 Ngamwongwan Road, Lad Yao, Chatuchak, Bangkok, Thailand
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Aix Marseille University, CEA, CNRS, BIAM, Saint-Paul-Lez-Durance, Marseille F, France
| | - Yonghua Li-Beisson
- Aix Marseille University, CEA, CNRS, BIAM, Saint-Paul-Lez-Durance, Marseille F, France
| | - Christoph Benning
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Plant Research Laboratory, US Department of Energy, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
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57
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Liu J, Sun Z, Mao X, Gerken H, Wang X, Yang W. Multiomics analysis reveals a distinct mechanism of oleaginousness in the emerging model alga Chromochloris zofingiensis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:1060-1077. [PMID: 30828893 DOI: 10.1111/tpj.14302] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
Chromochloris zofingiensis, featured due to its capability to simultaneously synthesize triacylglycerol (TAG) and astaxanthin, is emerging as a leading candidate alga for production uses. To better understand the oleaginous mechanism of this alga, we conducted a multiomics analysis by systematically integrating time-resolved transcriptomes, lipidomes and metabolomes in response to nitrogen deprivation. The data analysis unraveled the distinct mechanism of TAG accumulation, which involved coordinated stimulation of multiple biological processes including supply of energy and reductants, carbon reallocation from protein and starch, and 'pushing' and 'pulling' carbon to TAG synthesis. Unlike the model alga Chlamydomonas, de novo fatty acid synthesis in C. zofingiensis was promoted, together with enhanced turnover of both glycolipids and phospholipids, supporting the drastic need of acyls for TAG assembly. Moreover, genomewide analysis identified many key functional enzymes and transcription factors that had engineering potential for TAG modulation. Two genes encoding glycerol-3-phosphate acyltransferase (GPAT), the first committed enzyme for TAG assembly, were found in the C. zofingiensis genome; in vivo functional characterization revealed that extrachloroplastic GPAT instead of chloroplastic GPAT played a central role in TAG synthesis. These findings illuminate distinct oleaginousness mechanisms in C. zofingiensis and pave the way towards rational manipulation of this alga to becone an emerging model for trait improvements.
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Affiliation(s)
- Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Zheng Sun
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Henri Gerken
- School of Sustainable Engineering and the Built Environment, Arizona State University Polytechnic campus, Mesa, AZ, 85212, USA
| | - Xiaofei Wang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Wenqiang Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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58
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Kong F, Yamaoka Y, Ohama T, Lee Y, Li-Beisson Y. Molecular Genetic Tools and Emerging Synthetic Biology Strategies to Increase Cellular Oil Content in Chlamydomonas reinhardtii. PLANT & CELL PHYSIOLOGY 2019; 60:1184-1196. [PMID: 30715500 DOI: 10.1093/pcp/pcz022] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/18/2019] [Indexed: 05/26/2023]
Abstract
Microalgae constitute a highly diverse group of eukaryotic and photosynthetic microorganisms that have developed extremely efficient systems for harvesting and transforming solar energy into energy-rich molecules such as lipids. Although microalgae are considered to be one of the most promising platforms for the sustainable production of liquid oil, the oil content of these organisms is naturally low, and algal oil production is currently not economically viable. Chlamydomonas reinhardtii (Chlamydomonas) is an established algal model due to its fast growth, high transformation efficiency, and well-understood physiology and to the availability of detailed genome information and versatile molecular tools for this organism. In this review, we summarize recent advances in the development of genetic manipulation tools for Chlamydomonas, from gene delivery methods to state-of-the-art genome-editing technologies and fluorescent dye-based high-throughput mutant screening approaches. Furthermore, we discuss practical strategies and toolkits that enhance transgene expression, such as choice of expression vector and background strain. We then provide examples of how advanced genetic tools have been used to increase oil content in Chlamydomonas. Collectively, the current literature indicates that microalgal oil content can be increased by overexpressing key enzymes that catalyze lipid biosynthesis, blocking lipid degradation, silencing metabolic pathways that compete with lipid biosynthesis and modulating redox state. The tools and knowledge generated through metabolic engineering studies should pave the way for developing a synthetic biological approach to enhance lipid productivity in microalgae.
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Affiliation(s)
- Fantao Kong
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, China
| | - Yasuyo Yamaoka
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
| | - Takeshi Ohama
- School of Environmental Science and Engineering, Kochi University of Technology (KUT), Tosayamada, Kochi, Japan
| | - Youngsook Lee
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- Department of Life Science, Pohang University of Science and Technology, Pohang, Korea
| | - Yonghua Li-Beisson
- Aix-Marseille Univ., CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F, France
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59
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Solovchenko A, Baulina O, Ptushenko O, Gorelova O. Ultrastructural patterns of photoacclimation and photodamage to photosynthetic algae cell under environmental stress. PHYSIOLOGIA PLANTARUM 2019; 166:251-263. [PMID: 30561763 DOI: 10.1111/ppl.12912] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/05/2018] [Accepted: 12/17/2018] [Indexed: 05/16/2023]
Abstract
In oxygenic phototrophs including unicellular algae, acclimation to and damage by diverse environmental stresses induce profound changes in the ultrastructural organization of the cell. These alterations reflect acclimation of the photosynthetic apparatus to unfavorable conditions (mainly reduction of the chloroplast and its membranal system) and rewiring of the photo-fixed carbon fluxes in the cell. These changes, eventually pursuing mitigation of the photooxidative damage risk, are manifested by the formation of diverse carbon-rich inclusions. Although the physiological and molecular basis of these processes are well understood, the ultrastructural manifestations of the stress responses are often fragmented and frequently controversial. This minireview attempts to generalize on the ultrastructural patterns accompanying stresses in the photosynthetic cell, involving the concerted rearrangements of its assimilatory and storage compartments. The changes characteristic of normal functioning and emergency reduction of the chloroplast thylakoids under harsh stress are also addressed. Special attention is paid to the manifestations of the engagement of photoprotection via active (energy-dependent non-photochemical quenching) and passive mechanisms (e.g. optical shielding by secondary carotenoids). We also underline the potentially important role of autophagy-like processes and provide a more integral view of ultrastructural rearrangements under stress.
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Affiliation(s)
- Alexei Solovchenko
- Department of Bioengineering, Faculty of Biology, Moscow State University, Moscow, 119234, Russia
- Institute of Agriculture and Technolgy, Peoples Friendship University of Russia (RUDN University), Moscow, 117198, Russia
| | - Olga Baulina
- Department of Bioengineering, Faculty of Biology, Moscow State University, Moscow, 119234, Russia
| | - Oksana Ptushenko
- Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, 119991, Russia
| | - Olga Gorelova
- Department of Bioengineering, Faculty of Biology, Moscow State University, Moscow, 119234, Russia
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60
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Wang L, Huang X, Lim DJ, Laserna AKC, Li SFY. Uptake and toxic effects of triphenyl phosphate on freshwater microalgae Chlorella vulgaris and Scenedesmus obliquus: Insights from untargeted metabolomics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 650:1239-1249. [PMID: 30308812 DOI: 10.1016/j.scitotenv.2018.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 09/02/2018] [Accepted: 09/03/2018] [Indexed: 05/25/2023]
Abstract
The flame retardant triphenyl phosphate (TPhP) has been widely detected in surface waters. Yet, little information is known regarding its impact on microalgae. We investigated the uptake and toxicity of TPhP on two freshwater microalgae Chlorella vulgaris (CV) and Scenedesmus obliquus (SO) after exposure to 10 μg/l-10 mg/l for 5 days. The presence of microalgae significantly enhanced TPhP degradation, with the final concentrations dropped to 5.5-35.1% of the original concentrations. Most of the medium TPhP were sorbed and transformed by microalgae in just one day. Growth of CV was inhibited in a concentration-dependent manner, whereas growth of SO were only inhibited significantly at 10 mg/l TPhP exposure. Mass spectrometry-based untargeted metabolomics revealed concentration- and species-dependent metabolic responses. Exposure to TPhP in CV resulted in enhanced respiration (increase of fumarate and malate) and osmoregulation (increase of sucrose and myo-inositol), synthesis of membrane lipids (accumulation of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), decrease of lysoglycerolipids, fatty acids, and glyceryl-glucoside). Exposure to TPhP in SO resulted in enhanced osmoregulation (increase of valine, proline, and raffinose) and lipolysis (decrease of MGDG, accumulation of fatty acids, lysophospholipids, and glycerol phosphate). Although chlorophyll a and b contents did not change significantly, decrease of chlorophyll derivatives was observed in both CV and SO at high exposure concentrations. Further bioassays confirmed that CV exhibited enhanced membrane integrity and decreased cellular reactive oxygen species (ROS) possibly as a defense strategy, whereas SO showed disruption of membrane integrity and induction of ROS at 10 mg/l exposure. This study demonstrated the potential of microalgae to remove TPhP in water, and offered new insights for the risk assessment of TPhP on freshwater microalgae using metabolomics.
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Affiliation(s)
- Lei Wang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore
| | - Xulei Huang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore
| | - Dorothy Jingwen Lim
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore
| | | | - Sam Fong Yau Li
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore; NUS Environmental Research Institute (NERI), #02-01, T-Lab Building (TL), 5A Engineering Drive 1, Singapore 117411, Singapore.
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61
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Li-Beisson Y, Thelen JJ, Fedosejevs E, Harwood JL. The lipid biochemistry of eukaryotic algae. Prog Lipid Res 2019; 74:31-68. [PMID: 30703388 DOI: 10.1016/j.plipres.2019.01.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 02/06/2023]
Abstract
Algal lipid metabolism fascinates both scientists and entrepreneurs due to the large diversity of fatty acyl structures that algae produce. Algae have therefore long been studied as sources of genes for novel fatty acids; and, due to their superior biomass productivity, algae are also considered a potential feedstock for biofuels. However, a major issue in a commercially viable "algal oil-to-biofuel" industry is the high production cost, because most algal species only produce large amounts of oils after being exposed to stress conditions. Recent studies have therefore focused on the identification of factors involved in TAG metabolism, on the subcellular organization of lipid pathways, and on interactions between organelles. This has been accompanied by the development of genetic/genomic and synthetic biological tools not only for the reference green alga Chlamydomonas reinhardtii but also for Nannochloropsis spp. and Phaeodactylum tricornutum. Advances in our understanding of enzymes and regulatory proteins of acyl lipid biosynthesis and turnover are described herein with a focus on carbon and energetic aspects. We also summarize how changes in environmental factors can impact lipid metabolism and describe present and potential industrial uses of algal lipids.
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Affiliation(s)
- Yonghua Li-Beisson
- Aix-Marseille Univ, CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F-13108, France.
| | - Jay J Thelen
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - Eric Fedosejevs
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.
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62
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Xu Y, Falarz L, Chen G. Characterization of Type-2 Diacylglycerol Acyltransferases in the Green Microalga Chromochloris zofingiensis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:291-298. [PMID: 30543104 DOI: 10.1021/acs.jafc.8b05755] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Diacylglycerol acyltransferase (DGAT) catalyzes the last and committed step of the acyl-CoA-dependent TAG biosynthesis and thus is a key target for manipulating oil production in microalgae. The microalga Chromochloris zofingiensis can accumulate substantial amounts of triacylglycerol (TAG) and represents a promising source of algal lipids. In this study, C. zofingiensis DGAT2s (CzDGAT2s) were characterized with in silico, in vivo (yeast), and in vitro assays. Putative CzDGAT2s were identified, and their functional motifs and evolutionary relationship with other DGAT2s were analyzed. When CzDGAT2s were individually expressed in a TAG-deficient Saccharomyces cerevisiae strain, only CzDGAT2C could restore the TAG biosynthesis. Further in vitro assays indicated that CzDGAT2C displayed typical DGAT activity, which was fitted to the Michaelis-Menten equation, and N- and C-terminals were important for the enzyme activity. In addition, membrane yeast two-hybrid assay revealed a possible DGAT2 activity modulation via the formation of homodimer/heterodimer among different DGAT2 isoforms.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science , University of Alberta , Edmonton , Alberta , Canada T6G 2P5
| | - Lucas Falarz
- Department of Agricultural, Food and Nutritional Science , University of Alberta , Edmonton , Alberta , Canada T6G 2P5
- Department of Biological Sciences , University of Manitoba , Winnipeg , Manitoba , Canada R3T 2N2
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science , University of Alberta , Edmonton , Alberta , Canada T6G 2P5
- Department of Biological Sciences , University of Manitoba , Winnipeg , Manitoba , Canada R3T 2N2
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Li N, Zhang Y, Meng H, Li S, Wang S, Xiao Z, Chang P, Zhang X, Li Q, Guo L, Igarashi Y, Luo F. Characterization of Fatty Acid Exporters involved in fatty acid transport for oil accumulation in the green alga Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:14. [PMID: 30651755 PMCID: PMC6330502 DOI: 10.1186/s13068-018-1332-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/06/2018] [Indexed: 05/03/2023]
Abstract
BACKGROUND In the past few decades, microalgae biofuel has become one of the most interesting sources of renewable energy. However, the higher cost of microalgae biofuel compared to that of petroleum prevented microalgae biofuel production. Therefore, the research on increasing lipid productivity from microalgae becomes more important. The lipid production source, triacylglycerol biosynthesis in microalgae requires short chain fatty acids as substrates, which are synthesized in chloroplasts. However, the transport mechanism of fatty acids from microalgae chloroplasts to cytosol remains unknown. RESULTS cDNAs from two homologs of the Arabidopsis fatty acid exporter 1 (FAX1) were cloned from Chlamydomonas reinhardtii and were named crfax1 and crfax2. Both CrFAXs were involved in fatty acid transport, and their substrates were mainly C16 and C18 fatty acids. Overexpression of both CrFAXs increased the accumulation of the total lipid content in algae cells, and the fatty acid compositions were changed under normal TAP or nitrogen deprivation conditions. Overexpression of both CrFAXs also increased the chlorophyll content. The MGDG content was decreased but the TAG, DAG, DGDG and other lipid contents were increased in CrFAXs overexpression strains. CONCLUSION These results reveal that CrFAX1 and CrFAX2 were involved in mediating fatty acid export for lipids biosynthesis in C. reinhardtii. In addition, overexpression of both CrFAXs obviously increased the intracellular lipid content, especially the triacylglycerol content in microalgae, which provides a potential technology for the production of more biofuels using microalgae.
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Affiliation(s)
- Nannan Li
- Research Center of Bioremediation and Bioenergy, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
- Academy of Agricultural Science, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
| | - Yan Zhang
- Research Center of Bioremediation and Bioenergy, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
| | - Hongjun Meng
- Research Center of Bioremediation and Bioenergy, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
| | - Shengting Li
- Research Center of Bioremediation and Bioenergy, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
| | - Shufeng Wang
- Research Center of Bioremediation and Bioenergy, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
| | - Zhongchun Xiao
- Academy of Agricultural Science, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
| | - Peng Chang
- Research Center of Bioremediation and Bioenergy, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
| | - Xiaohui Zhang
- Research Center of Bioremediation and Bioenergy, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
| | - Qing Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 China
| | - Liang Guo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 China
| | - Yasuo Igarashi
- Research Center of Bioremediation and Bioenergy, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
| | - Feng Luo
- Research Center of Bioremediation and Bioenergy, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715 People’s Republic of China
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Lou S, Sun T, Li H, Hu Z. Mechanisms of microRNA-mediated gene regulation in unicellular model alga Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:244. [PMID: 30202439 PMCID: PMC6129010 DOI: 10.1186/s13068-018-1249-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 08/31/2018] [Indexed: 05/30/2023]
Abstract
MicroRNAs are a class of endogenous non-coding RNAs that play a vital role in post-transcriptional gene regulation in eukaryotic cells. In plants and animals, miRNAs are implicated in diverse roles ranging from immunity against viral infections, developmental pathways, molecular pathology of cancer and regulation of protein expression. However, the role of miRNAs in the unicellular model green alga Chlamydomonas reinhardtii remains unclear. The mode of action of miRNA-induced gene silencing in C. reinhardtii is very similar to that of higher eukaryotes, in terms of the activation of the RNA-induced silencing complex and mRNA targeting. Certain studies indicate that destabilization of mRNAs and mRNA turnover could be the major possible functions of miRNAs in eukaryotic algae. Here, we summarize recent findings that have advanced our understanding of miRNA regulatory mechanisms in C. reinhardtii.
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Affiliation(s)
- Sulin Lou
- Guangdong Key Laboratory of Plant Epigenetics, Guangdong Engineering Research Center for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060 People’s Republic of China
- Key Laboratory of Optoeletronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoeletronic Engineering, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Ting Sun
- Guangdong Key Laboratory of Plant Epigenetics, Guangdong Engineering Research Center for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060 People’s Republic of China
- Key Laboratory of Optoeletronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoeletronic Engineering, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Hui Li
- Guangdong Key Laboratory of Plant Epigenetics, Guangdong Engineering Research Center for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Zhangli Hu
- Guangdong Key Laboratory of Plant Epigenetics, Guangdong Engineering Research Center for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060 People’s Republic of China
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