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Sah SK, Fan J, Blanford J, Shanklin J, Xu C. Physiological Functions of Phospholipid:Diacylglycerol Acyltransferases. PLANT & CELL PHYSIOLOGY 2024; 65:863-871. [PMID: 37702708 DOI: 10.1093/pcp/pcad106] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/01/2023] [Accepted: 09/08/2023] [Indexed: 09/14/2023]
Abstract
Triacylglycerol (TAG) is among the most energy dense storage forms of reduced carbon in living systems. TAG metabolism plays critical roles in cellular energy balance, lipid homeostasis, cell growth and stress responses. In higher plants, microalgae and fungi, TAG is assembled by acyl-CoA-dependent and acyl-CoA-independent pathways catalyzed by diacylglycerol (DAG) acyltransferase and phospholipid:DAG acyltransferase (PDAT), respectively. This review contains a summary of the current understanding of the physiological functions of PDATs. Emphasis is placed on their role in lipid remodeling and lipid homeostasis in response to abiotic stress or perturbations in lipid metabolism.
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Affiliation(s)
- Saroj Kumar Sah
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Jantana Blanford
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | | | - Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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Kong F, Blot C, Liu K, Kim M, Li-Beisson Y. Advances in algal lipid metabolism and their use to improve oil content. Curr Opin Biotechnol 2024; 87:103130. [PMID: 38579630 DOI: 10.1016/j.copbio.2024.103130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/07/2024]
Abstract
Microalgae are eukaryotic photosynthetic micro-organisms that convert CO2 into carbohydrates, lipids, and other valuable metabolites. They are considered promising chassis for the production of various bioproducts, including fatty acid-derived biofuels. However, algae-based biofuels are not yet commercially available, mainly because of their low yields and high production cost. Optimizing strains to improve lipid productivity using the principles of synthetic biology should help move forward. This necessitates developments in the following areas: (1) identification of molecular bricks (enzymes, transcription factors, regulatory proteins etc.); (2) development of genetic tools; and (3) availability of high-throughput phenotyping methods. Here, we highlight the most recent developments in some of these areas and provide examples of the use of genome editing tools to improve oil content.
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Affiliation(s)
- Fantao Kong
- MOE Key Laboratory of Bio-Intelligent Manufacturing, School of Bioengineering, Dalian University of Technology, Dalian 116024, Liaoning, China.
| | - Carla Blot
- Aix Marseille Univ, CEA, CNRS, BIAM, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint Paul-Lez-Durance 13108, France
| | - Keqing Liu
- MOE Key Laboratory of Bio-Intelligent Manufacturing, School of Bioengineering, Dalian University of Technology, Dalian 116024, Liaoning, China
| | - Minjae Kim
- Aix Marseille Univ, CEA, CNRS, BIAM, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint Paul-Lez-Durance 13108, France
| | - Yonghua Li-Beisson
- Aix Marseille Univ, CEA, CNRS, BIAM, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint Paul-Lez-Durance 13108, France
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Xin Y, Wu S, Miao C, Xu T, Lu Y. Towards Lipid from Microalgae: Products, Biosynthesis, and Genetic Engineering. Life (Basel) 2024; 14:447. [PMID: 38672718 PMCID: PMC11051065 DOI: 10.3390/life14040447] [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: 01/13/2024] [Revised: 03/27/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Microalgae can convert carbon dioxide into organic matter through photosynthesis. Thus, they are considered as an environment-friendly and efficient cell chassis for biologically active metabolites. Microalgal lipids are a class of organic compounds that can be used as raw materials for food, feed, cosmetics, healthcare products, bioenergy, etc., with tremendous potential for commercialization. In this review, we summarized the commercial lipid products from eukaryotic microalgae, and updated the mechanisms of lipid synthesis in microalgae. Moreover, we reviewed the enhancement of lipids, triglycerides, polyunsaturated fatty acids, pigments, and terpenes in microalgae via environmental induction and/or metabolic engineering in the past five years. Collectively, we provided a comprehensive overview of the products, biosynthesis, induced strategies and genetic engineering in microalgal lipids. Meanwhile, the outlook has been presented for the development of microalgal lipids industries, emphasizing the significance of the accurate analysis of lipid bioactivity, as well as the high-throughput screening of microalgae with specific lipids.
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Affiliation(s)
- Yi Xin
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Life and Aquaculture, Hainan University, Haikou 570228, China; (S.W.); (C.M.); (T.X.)
- Haikou Technology Innovation Center for Research and Utilization of Algal Bioresources, Hainan University, Haikou 570228, China
| | - Shan Wu
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Life and Aquaculture, Hainan University, Haikou 570228, China; (S.W.); (C.M.); (T.X.)
| | - Congcong Miao
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Life and Aquaculture, Hainan University, Haikou 570228, China; (S.W.); (C.M.); (T.X.)
| | - Tao Xu
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Life and Aquaculture, Hainan University, Haikou 570228, China; (S.W.); (C.M.); (T.X.)
| | - Yandu Lu
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Life and Aquaculture, Hainan University, Haikou 570228, China; (S.W.); (C.M.); (T.X.)
- Haikou Technology Innovation Center for Research and Utilization of Algal Bioresources, Hainan University, Haikou 570228, China
- Hainan Provincial Key Laboratory of Tropical Hydrobiotechnology, Hainan University, Haikou 570228, China
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Wu Y, Zhu H, Ling Z, Lu E, Peng X, Zheng Y. The metabolism of nonstructural carbohydrates, lipids, and energy in two Cycas species with differential tolerance to unexpected freezing stress. FRONTIERS IN PLANT SCIENCE 2023; 14:1301560. [PMID: 38143575 PMCID: PMC10740210 DOI: 10.3389/fpls.2023.1301560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/17/2023] [Indexed: 12/26/2023]
Abstract
Introduction With the climate warming, the occurrence of freezing events is projected to increase in late spring and early autumn in the Northern Hemisphere. Observation of morphological traits showed that Cycas panzhihuaensis was more tolerant to unexpected freezing stress than C. bifida. Energy balance is crucial for plant tolerance to stress. Here, we aimed to determine whether the different responses of the two species to the unpredicted freezing stress were associated with the metabolism of energy and related substances. Methods The effects of unexpected freezing temperatures on C. panzhihuaensis and C. bifida were studied by measuring chlorophyll fluorescence parameters, energy charge and the profile of nonstructural carbohydrates (NSC) and lipids. Results C. panzhihuaensis exhibited higher stability of photosynthetic machinery than C. bifida under unpredicted freezing events. Significant interaction between species and treatments were observed in the energy charge, the level of NSC and its most components and the amount of most lipid categories and lipid classes. The decrease of soluble sugar and the increase of neutral glycerolipids at the early freezing stage, the accumulation of membrane glycerolipids at the late freezing stage and the continuous decrease of energy charge during the freezing period were the characteristics of C. panzhihuaensis responding to unexpected freezing stress. The degradation of membrane glycerolipids and the continuous decrease of soluble sugar during the freezing period and the accumulation of neutral glycerolipids and energy charge at the late freezing stage represented the characteristics of C. bifida responses. Discussion The different freezing sensitivity between C. panzhihuaensis and C. bifida might be associated with the differential patterns of the metabolism of energy, NSC and lipids. C. panzhihuaensis possesses the potential to be introduced to the areas of higher latitudes and altitudes.
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Affiliation(s)
| | | | | | | | | | - Yanling Zheng
- Key Laboratory of State Forestry and Grassland Administration for Biodiversity Conservation in Southwest China, Southwest Forestry University, Kunming, Yunnan, China
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Wang R, Li J, Zhang F, Miao X. Non-Tandem CCCH-Type Zinc-Finger Protein CpZF_CCCH1 Improves Fatty Acid Desaturation and Stress Tolerance in Chlamydomonas reinhardtii. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023. [PMID: 37910392 DOI: 10.1021/acs.jafc.3c05511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
The properties and nutritional value of microalgal bioproducts depend significantly on fatty acid desaturation, which is generally modulated by manipulating the culture conditions or associated gene expressions. Here, we investigated the role of CpZF_CCCH1, a non-tandem CCCH-type zinc-finger (non-TZF) protein, in elevating polyunsaturated fatty acid (PUFA) content (11.00-16.36%) in Chlamydomonas reinhardtii. Through lipidomic and flow cytometry analyses, we observed reduced triacylglycerol accumulation (7.01-21.15%) and elevated levels of membrane lipids containing PUFAs (7.81-46.18%) in C. reinhardtii overexpressing CpZF_CCCH1. Additionally, overexpression of nucleus-located CpZF_CCCH1 downregulated genes associated with triacylglycerol assembly and lipid turnover from 2.00- to 2.90-fold, likely by binding to GCN4 motif and promoter of 3-phosphate-glycerol acyltransferase. Furthermore, overexpression of CpZF_CCCH1 alleviated reactive oxygen species levels by 59.28-73.26% and enhanced stress tolerance under adverse conditions. These findings expanded the roles of non-TZF proteins in lipid metabolism, opening new avenues for metabolic engineering to enhance the nutritional value and stress tolerance of microalgae and agricultural crops.
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Affiliation(s)
- Rui Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
- Biomass Energy Research Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Junhao Li
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
- Biomass Energy Research Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Feng Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
- Biomass Energy Research Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaoling Miao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
- Biomass Energy Research Center, Shanghai Jiao Tong University, Shanghai 200240, China
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Li X, Dong Y, Chen K, Perumal AB, Zhan Z, Gouda M, He Y. 13C-metabolic flux analysis of lipid accumulation in the green microalgae Tetradesmus obliquus under nitrogen deficiency stress. BIORESOURCE TECHNOLOGY 2023; 388:129740. [PMID: 37717702 DOI: 10.1016/j.biortech.2023.129740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/23/2023] [Accepted: 09/06/2023] [Indexed: 09/19/2023]
Abstract
Metabolic fluxes (MF) serve as the functional phenotypes of biochemical processes and are crucial to describe the distribution of precursors within metabolic networks. There is a lack of experimental observations for carbon flux towards lipids, which is important for biodiesel generation. Here, the accumulation of lipid, and MF in Tetradesmus obliquus under nitrogen deficiency stress (NF) using a 13C isotope tracer at different time intervals was investigated. The 13C based MF showed enhanced de novo synthesis of G3P and PEP, indicating increased carbon flux from CO2 into lipid synthesis. An increase in palmitic acid (3500 μmol/mg), linoleic acid (2100 μmol/mg), and oleic acid (2000 μmol/mg) was observed. The accumulation of C16:0 under NF was mainly related to de novo synthesis while C18:3 was accumulated through a non de novo pathway. Under NF stress, T. obliquus had higher flux in PPP and glycolysis pathway, together, it might provide more NADPH and substrate acetyl-CoA for fatty acid synthesis.
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Affiliation(s)
- Xiaoli Li
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Yulun Dong
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Kai Chen
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Anand Babu Perumal
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.
| | - Zhihao Zhan
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Mostafa Gouda
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China; Department of Nutrition & Food Science, National Research Centre, Dokki, Giza 12622, Egypt
| | - Yong He
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
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Shitanaka T, Higa L, Bryson AE, Bertucci C, Vande Pol N, Lucker B, Khanal SK, Bonito G, Du ZY. Flocculation of oleaginous green algae with Mortierella alpina fungi. BIORESOURCE TECHNOLOGY 2023; 385:129391. [PMID: 37364649 DOI: 10.1016/j.biortech.2023.129391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023]
Abstract
Microalgae are promising sources of valuable bioproducts such as biofuels, food, and nutraceuticals. However, harvesting microalgae is challenging due to their small size and low biomass concentrations. To address this challenge, bio-flocculation of starchless mutants of Chlamydomonas reinhardtii (sta6/sta7) was investigated with Mortierella alpina, an oleaginous fungus with high concentrations of arachidonic acid (ARA). Triacylglycerides (TAG) reached 85 % of total lipids in sta6 and sta7 through a nitrogen regime. Scanning electron microscopy determined cell-wall attachment and extra polymeric substances (EPS) to be responsible for flocculation. An algal-fungal biomass ratio around 1:1 (three membranes) was optimal for bio-flocculation (80-85 % flocculation efficiency in 24 h). Nitrogen-deprived sta6/sta7 were flocculated with strains of M. alpina (NVP17b, NVP47, and NVP153) with aggregates exhibiting fatty acid profiles similar to C. reinhardtii, with ARA (3-10 % of total fatty acids). This study showcases M. alpina as a strong bio-flocculation candidate for microalgae and advances a mechanistic understanding of algal-fungal interaction.
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Affiliation(s)
- Ty Shitanaka
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Lauren Higa
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Abigail E Bryson
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
| | - Conor Bertucci
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
| | - Natalie Vande Pol
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
| | - Ben Lucker
- Trait Biosciences, Los Alamos, NM 87544, United States
| | - Samir Kumar Khanal
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States; Department of Civil and Environmental Engineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Gregory Bonito
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States.
| | - Zhi-Yan Du
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States.
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Hoffmann DY, Shachar-Hill Y. Do betaine lipids replace phosphatidylcholine as fatty acid editing hubs in microalgae? FRONTIERS IN PLANT SCIENCE 2023; 14:1077347. [PMID: 36743481 PMCID: PMC9892843 DOI: 10.3389/fpls.2023.1077347] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
Acyl editing refers to a deacylation and reacylation cycle on a lipid, which allows for fatty acid desaturation and modification prior to being removed and incorporated into other pools. Acyl editing is an important determinant of glycerolipid synthesis and has been well-characterized in land plants, thus this review begins with an overview of acyl editing in plants. Much less is known about acyl editing in algae, including the extent to which acyl editing impacts lipid synthesis and on which lipid substrate(s) it occurs. This review compares what is known about acyl editing on its major hub phosphatidylcholine (PC) in land plants with the evidence for acyl editing of betaine lipids such as diacylglyceryltrimethylhomoserine (DGTS), the structural analog that replaces PC in several species of microalgae. In land plants, PC is also known to be a major source of fatty acids and diacylglycerol (DAG) for synthesis of the neutral lipid triacylglycerol (TAG). We review the evidence that DGTS contributes substantially to TAG accumulation in algae as a source of fatty acids, but not as a precursor to DAG. We conclude with evidence of acyl editing on other membrane lipid substrates in plants and algae apart from PC or DGTS, and discuss future analyses to elucidate the role of DGTS and other betaine lipids in acyl editing in microalgae.
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Li X, Lan C, Li X, Hu Z, Jia B. A review on design-build-test-learn cycle to potentiate progress in isoprenoid engineering of photosynthetic microalgae. BIORESOURCE TECHNOLOGY 2022; 363:127981. [PMID: 36130687 DOI: 10.1016/j.biortech.2022.127981] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 06/15/2023]
Abstract
Currently, the generation of isoprenoid factories in microalgae relies on two strategies: 1) enhanced production of endogenous isoprenoids; or 2) production of heterologous terpenes by metabolic engineering. Nevertheless, low titers and productivity are still a feature of isoprenoid biotechnology and need to be addressed. In this context, the mechanisms underlying isoprenoid biosynthesis in microalgae and its relationship with central carbon metabolism are reviewed. Developments in microalgal biotechnology are discussed, and a new approach of integrated "design-build-test-learn" cycle is advocated to the trends, challenges and prospects involved in isoprenoid engineering. The emerging and promising strategies and tools are discussed for microalgal engineering in the future. This review encourages a systematic engineering perspective aimed at potentiating progress in isoprenoid engineering of photosynthetic microalgae.
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Affiliation(s)
- Xiangyu Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Chengxiang Lan
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Xinyi Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Zhangli Hu
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Bin Jia
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
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Wang R, Miao X. Lipid turnover and SQUAMOSA promoter-binding proteins mediate variation in fatty acid desaturation under early nitrogen deprivation revealed by lipidomic and transcriptomic analyses in Chlorella pyrenoidosa. FRONTIERS IN PLANT SCIENCE 2022; 13:987354. [PMID: 36247620 PMCID: PMC9558234 DOI: 10.3389/fpls.2022.987354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 09/06/2022] [Indexed: 06/16/2023]
Abstract
Nitrogen deprivation induces variations in fatty acid desaturation in microalgae, which determines the performance of biodiesel and the nutritional value of bioproducts. However, the detailed scenario and the underlying regulatory mechanism remain unclear. In this study, we attempt to outline these scenario and mechanisms by performing biochemical, lipidomic, and transcriptomic analyses in Chlorella pyrenoidosa and functional characterization of transcription factors in Yarrowia lipolytica. We found that early nitrogen deprivation dramatically reduced fatty acid desaturation without increasing lipid content. The contents of palmitic acid (16:0) and oleic acid (18:1) dramatically increased to 2.14 and 2.87 times that of nitrogen repletion on the second day, respectively. Lipidomic analysis showed the transfer of polyunsaturated fatty acids from phospholipids and glycolipids to triacylglycerols, and an increase in lipid species with 16:0 or 18:1 under nitrogen deprivation conditions. Upregulated stearoyl-ACP desaturase and oleyl-ACP thioesterase promoted the synthesis of 18:1, but restricted acetyl-CoA supply revealed that it was the intensive lipid turnover instead of an attenuated Kennedy pathway that played an important role in the variation in fatty acid composition under early nitrogen deprivation. Finally, two differentially expressed SQUAMOSA promoter-binding proteins (SBPs) were heterologously expressed in Y. lipolytica, demonstrating their role in promoting the accumulation of total fatty acid and the reduction in fatty acid desaturation. These results revealed the crucial role of lipid turnover and SBPs in determining fatty acid desaturation under early nitrogen deprivation, opening new avenues for the metabolic engineering of fatty acid desaturation in microalgae.
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Affiliation(s)
- Rui Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai, China
- Biomass Energy Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoling Miao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai, China
- Biomass Energy Research Center, Shanghai Jiao Tong University, Shanghai, China
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