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Fujiwara T, Hirooka S, Yamashita S, Yagisawa F, Miyagishima SY. Development of a rapamycin-inducible protein-knockdown system in the unicellular red alga Cyanidioschyzon merolae. PLANT PHYSIOLOGY 2024; 196:77-94. [PMID: 38833589 PMCID: PMC11376382 DOI: 10.1093/plphys/kiae316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 04/25/2024] [Accepted: 05/14/2024] [Indexed: 06/06/2024]
Abstract
An inducible protein-knockdown system is highly effective for investigating the functions of proteins and mechanisms essential for the survival and growth of organisms. However, this technique is not available in photosynthetic eukaryotes. The unicellular red alga Cyanidioschyzon merolae possesses a very simple cellular and genomic architecture and is genetically tractable but lacks RNA interference machinery. In this study, we developed a protein-knockdown system in this alga. The constitutive system utilizes the destabilizing activity of the FK506-binding protein 12 (FKBP12)-rapamycin-binding (FRB) domain of human target of rapamycin kinase or its derivatives to knock down target proteins. In the inducible system, rapamycin treatment induces the heterodimerization of the human FRB domain fused to the target proteins with the human FKBP fused to S-phase kinase-associated protein 1 or Cullin 1, subunits of the SCF E3 ubiquitin ligase. This results in the rapid degradation of the target proteins through the ubiquitin-proteasome pathway. With this system, we successfully degraded endogenous essential proteins such as the chloroplast division protein dynamin-related protein 5B and E2 transcription factor, a regulator of the G1/S transition, within 2 to 3 h after rapamycin administration, enabling the assessment of resulting phenotypes. This rapamycin-inducible protein-knockdown system contributes to the functional analysis of genes whose disruption leads to lethality.
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Affiliation(s)
- Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka 411-8540, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Shizuoka 411-8540, Japan
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka 411-8540, Japan
| | - Shota Yamashita
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka 411-8540, Japan
| | - Fumi Yagisawa
- Research Facility Center, University of the Ryukyus, Okinawa 903-0213, Japan
| | - Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka 411-8540, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Shizuoka 411-8540, Japan
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Li Y, Zhao T, Gao W, Miao B, Fu Z, Zhang Z, Li Q, Sun D. Regulatory mechanisms of autophagy on DHA and carotenoid accumulation in Crypthecodinium sp. SUN. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:50. [PMID: 38566214 PMCID: PMC10985998 DOI: 10.1186/s13068-024-02493-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 03/14/2024] [Indexed: 04/04/2024]
Abstract
BACKGROUND Autophagy is a crucial process of cellular self-destruction and component reutilization that can affect the accumulation of total fatty acids (TFAs) and carotenoids in microalgae. The regulatory effects of autophagy process in a docosahexaenoic acid (DHA) and carotenoids simultaneously producing microalga, Crypthecodinium sp. SUN, has not been studied. Thus, the autophagy inhibitor (3-methyladenine (MA)) and activator (rapamycin) were used to regulate autophagy in Crypthecodinium sp. SUN. RESULTS The inhibition of autophagy by 3-MA was verified by transmission electron microscopy, with fewer autophagy vacuoles observed. Besides, 3-MA reduced the glucose absorption and intracellular acetyl-CoA level, which resulting in the decrease of TFA and DHA levels by 15.83 and 26.73% respectively; Surprisingly, 3-MA increased intracellular reactive oxygen species level but decreased the carotenoids level. Comparative transcriptome analysis showed that the downregulation of the glycolysis, pentose phosphate pathway and tricarboxylic acid cycle may underlie the decrease of acetyl-CoA, NADPH and ATP supply for fatty acid biosynthesis; the downregulation of PSY and HMGCR may underlie the decreased carotenoids level. In addition, the class I PI3K-AKT signaling pathway may be crucial for the regulation of carbon and energy metabolism. At last, rapamycin was used to activate autophagy, which significantly enhanced the cell growth and TFA level and eventually resulted in 1.70-fold increase in DHA content. CONCLUSIONS Our findings indicate the mechanisms of autophagy in Crypthecodinium sp. SUN and highlight a way to manipulate cell metabolism by regulating autophagy. Overall, this study provides valuable insights to guide further research on autophagy-regulated TFA and carotenoids accumulation in Crypthecodinium sp. SUN.
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Affiliation(s)
- Yiming Li
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- School of Life Sciences, Hebei University, Baoding, 071000, China
| | - Tiantian Zhao
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
| | - Weizheng Gao
- School of Life Sciences, Hebei University, Baoding, 071000, China
| | - Bowen Miao
- School of Life Sciences, Hebei University, Baoding, 071000, China
| | - Zhongxiang Fu
- School of Life Sciences, Hebei University, Baoding, 071000, China
| | - Zhao Zhang
- School of Life Sciences, Hebei University, Baoding, 071000, China
| | - Qingyang Li
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China.
| | - Dongzhe Sun
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Hebei Research Center of the Basic Discipline of Cell Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China.
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Chen D, Chen J, Dai R, Zheng X, Han Y, Chen Y, Xue T. Integration analysis of ATAC-seq and RNA-seq provides insight into fatty acid biosynthesis in Schizochytrium limacinum under nitrogen limitation stress. BMC Genomics 2024; 25:141. [PMID: 38311722 PMCID: PMC10840233 DOI: 10.1186/s12864-024-10043-5] [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: 06/08/2023] [Accepted: 01/22/2024] [Indexed: 02/06/2024] Open
Abstract
BACKGROUND Schizochytrium limacinum holds significant value utilized in the industrial-scale synthesis of natural DHA. Nitrogen-limited treatment can effectively increase the content of fatty acids and DHA, but there is currently no research on chromatin accessibility during the process of transcript regulation. The objective of this research was to delve into the workings of fatty acid production in S. limacinum by examining the accessibility of promoters and profiling gene expressions. RESULTS Results showed that differentially accessible chromatin regions (DARs)-associated genes were enriched in fatty acid metabolism, signal transduction mechanisms, and energy production. By identifying and annotating DARs-associated motifs, the study obtained 54 target transcription factor classes, including BPC, RAMOSA1, SPI1, MYC, and MYB families. Transcriptomics results revealed that several differentially expressed genes (DEGs), including SlFAD2, SlALDH, SlCAS1, SlNSDHL, and SlDGKI, are directly related to the biosynthesis of fatty acids, meanwhile, SlRPS6KA, SlCAMK1, SlMYB3R1, and SlMYB3R5 serve as transcription factors that could potentially influence the regulation of fatty acid production. In the integration analysis of DARs and ATAC-seq, 13 genes were identified, which were shared by both DEGs and DARs-associated genes, including SlCAKM, SlRP2, SlSHOC2, SlTN, SlSGK2, SlHMP, SlOGT, SlclpB, and SlDNAAF3. CONCLUSIONS SlCAKM may act as a negative regulator of fatty acid and DHA synthesis, while SlSGK2 may act as a positive regulator, which requires further study in the future. These insights enhance our comprehension of the processes underlying fatty acid and DHA production in S. limacinum. They also supply a foundational theoretical framework and practical assistance for the development of strains rich in fatty acids and DHA.
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Affiliation(s)
- Duo Chen
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Jing Chen
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Rongchun Dai
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Xuehai Zheng
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yuying Han
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Youqiang Chen
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Ting Xue
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China.
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Cui Y, Wang K, Zhou X, Meng C, Gao Z. Lipid accumulation mechanism of Amphora coffeaeformis under nitrogen deprivation and its application as a feed additive in Carassius auratus aquaculture. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:189. [PMID: 38057940 DOI: 10.1186/s13068-023-02436-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/21/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND Amphora coffeaeformis, a unicellular diatom, can significantly accumulate lipids under nitrogen (N) limitation. However, the molecular mechanism underlying lipid accumulation in A. coffeaeformis remains unknown and its application development is lagging. RESULTS This work analyzed the lipid composition of A. coffeaeformis under N deprivation and investigated its mechanism underlying lipid accumulation using RNA-seq. The results showed that the total lipid content of A. coffeaeformis increased from 28.22 to 44.05% after 5 days of N deprivation, while the neutral lipid triacylglycerol (TAG) content increased from 10.41 to 25.21%. The transcriptional profile showed that N deprivation induced wide-ranging reprogramming of regulation and that most physiological activities were repressed, while the upregulation of glycerol-3-phosphate acyltransferase directly determined TAG accumulation. Moreover, we explored the effect of A. coffeaeformis as a food additive on the lipid composition of crucian carp. The results showed that the contents of unsaturated fatty acids in the meat of fish supplemented with A. coffeaeformis were significantly increased, indicating its potential application in animal nutrition for improving meat quality indicators. CONCLUSION The findings shed light on the molecular mechanisms of neutral lipid accumulation and revealed the key genes involved in lipid metabolism in A. coffeaeformis. Moreover, we also confirmed that A. coffeaeformis can be used as feed additive for improving the lipid composition of crucian carp meat, which provided evidence for the biotechnology application of this high-oil microalgae.
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Affiliation(s)
- Yulin Cui
- Binzhou Medical University, No. 346, Guanhai Road, Laishan District, Yantai, 256603, Shandong Province, China
| | - Kang Wang
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, Shandong, China
- University of Chinese Academy of Sciences, Beijing, Beijing, 101418, China
| | - Xiuzhi Zhou
- Binzhou Medical University, No. 346, Guanhai Road, Laishan District, Yantai, 256603, Shandong Province, China
| | - Chunxiao Meng
- Binzhou Medical University, No. 346, Guanhai Road, Laishan District, Yantai, 256603, Shandong Province, China
| | - Zhengquan Gao
- Binzhou Medical University, No. 346, Guanhai Road, Laishan District, Yantai, 256603, Shandong Province, China.
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Nishii M, Ito S, Osanai T. Citrate synthase from Cyanidioschyzon merolae exhibits high oxaloacetate and acetyl-CoA catalytic efficiency. PLANT MOLECULAR BIOLOGY 2023; 111:429-438. [PMID: 36884198 DOI: 10.1007/s11103-023-01335-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Citrate synthase (CS) catalyzes the reaction that produces citrate and CoA from oxaloacetate and acetyl-CoA in the tricarboxylic acid (TCA) cycle. All TCA cycle enzymes are localized to the mitochondria in the model organism, the red alga Cyanidioschyzon merolae. The biochemical properties of CS have been studied in some eukaryotes, but the biochemical properties of CS in algae, including C. merolae, have not been studied. We then performed the biochemical analysis of CS from C. merolae mitochondria (CmCS4). The results showed that the kcat/Km of CmCS4 for oxaloacetate and acetyl-CoA were higher than those of the cyanobacteria, such as Synechocystis sp. PCC 6803, Microcystis aeruginosa PCC 7806 and Anabaena sp. PCC 7120. Monovalent and divalent cations inhibited CmCS4, and in the presence of KCl, the Km of CmCS4 for oxaloacetate and acetyl-CoA was higher in the presence of MgCl2, the Km of CmCS4 for oxaloacetate and acetyl-CoA was higher and kcat lower. However, in the presence of KCl and MgCl2, the kcat/Km of CmCS4 was higher than those of the three cyanobacteria species. The high catalytic efficiency of CmCS4 for oxaloacetate and acetyl-CoA may be a factor in the increased carbon flow into the TCA cycle in C. merolae.
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Affiliation(s)
- Maki Nishii
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, 214-8571, Kawasaki, Kanagawa, Japan
| | - Shoki Ito
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, 214-8571, Kawasaki, Kanagawa, Japan
| | - Takashi Osanai
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, 214-8571, Kawasaki, Kanagawa, Japan.
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Jia YL, Du F, Nong FT, Li J, Huang PW, Ma W, Gu Y, Sun XM. Function of the Polyketide Synthase Domains of Schizochytrium sp. on Fatty Acid Synthesis in Yarrowia lipolytica. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:2446-2454. [PMID: 36696156 DOI: 10.1021/acs.jafc.2c08383] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
It is well known that polyunsaturated fatty acids (PUFAs) in Schizochytrium sp. are mainly synthesized via the polyketide synthase (PKS) pathway. However, the specific mechanism of PKS in fatty acid synthesis is still unclear. In this work, the functions of ORFA, ORFB, ORFC, and their individual functional domain genes on fatty acid synthesis were investigated through heterologous expression in Yarrowia lipolytica. The results showed that the expression of ORFA, ORFB, ORFC, and their individual functional domains all led to the increase of the very long-chain PUFA content (mainly eicosapentaenoic acid). Furthermore, the transcriptomic analysis showed that except for the 3-ketoacyl-ACP synthase (KS) domain of ORFB, the expression of an individual functional domain, including malonyl-CoA: ACP acyltransferase, 3-hydroxyacyl-ACP dehydratase (DH), 3-ketoacyl-ACP reductase, and KS domains of ORFA, acyltransferase domains of ORFB, and two DH domains of ORFC resulted in upregulation of the tricarboxylic acid cycle and pentose phosphate pathway, downregulation of the triacylglycerol biosynthesis, fatty acid synthesis pathway, and β-oxidation in Yarrowia lipolytica. These results provide a theoretical basis for revealing the function of PKS in fatty acid synthesis in Y. lipolytica and elucidate the possible mechanism for PUFA biosynthesis.
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Affiliation(s)
- Yu-Lei Jia
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Fei Du
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Fang-Tong Nong
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Jin Li
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Peng-Wei Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Wang Ma
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Yang Gu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Xiao-Man Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
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Mallén-Ponce MJ, Pérez-Pérez ME, Crespo JL. Deciphering the function and evolution of the target of rapamycin signaling pathway in microalgae. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:6993-7005. [PMID: 35710309 PMCID: PMC9664231 DOI: 10.1093/jxb/erac264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
Microalgae constitute a highly diverse group of photosynthetic microorganisms that are widely distributed on Earth. The rich diversity of microalgae arose from endosymbiotic events that took place early in the evolution of eukaryotes and gave rise to multiple lineages including green algae, the ancestors of land plants. In addition to their fundamental role as the primary source of marine and freshwater food chains, microalgae are essential producers of oxygen on the planet and a major biotechnological target for sustainable biofuel production and CO2 mitigation. Microalgae integrate light and nutrient signals to regulate cell growth. Recent studies identified the target of rapamycin (TOR) kinase as a central regulator of cell growth and a nutrient sensor in microalgae. TOR promotes protein synthesis and regulates processes that are induced under nutrient stress such as autophagy and the accumulation of triacylglycerol and starch. A detailed analysis of representative genomes from the entire microalgal lineage revealed that the highly conserved central components of the TOR pathway are likely to have been present in the last eukaryotic common ancestor, and the loss of specific TOR signaling elements at an early stage in the evolution of microalgae. Here we examine the evolutionary conservation of TOR signaling components in diverse microalgae and discuss recent progress of this signaling pathway in these organisms.
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Affiliation(s)
- Manuel J Mallén-Ponce
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Sevilla, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Sevilla, Spain
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Ran Y, Xu H, Yang Q, Xu Y, Yang H, Qiao D, Cao Y. GATA-type transcriptional factor SpGAT1 interacts with SpMIG1 and promotes lipid accumulation in the oleaginous yeast [Formula: see text] zwy-2-3. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:103. [PMID: 36209175 PMCID: PMC9548168 DOI: 10.1186/s13068-022-02177-z] [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: 06/02/2022] [Accepted: 07/14/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND In oleaginous yeast, nitrogen limitation is a critical parameter for lipid synthesis. GATA-family transcriptional factor GAT1, a member of the target of rapamycin (TOR) pathway and nitrogen catabolite repression (NCR), regulates nitrogen uptake and utilization. Therefore, it is significant to study the SpGAT1 regulatory mechanism of lipid metabolism for conversion of biomass to microbial oil in [Formula: see text] zwy-2-3. RESULTS Compared with WT, [Formula: see text], and OE::gat1, the lipid yield of OE::gat1 increased markedly in the low carbon and nitrogen ratio (C/N ratio) mediums, while the lipid yield and residual sugar of [Formula: see text] decreased in the high C/N ratio medium. According to yeast two-hybrid assays, SpGAT1 interacted with SpMIG1, and its deletion drastically lowered SpMIG1 expression on the high C/N ratio medium. MIG1 deletion has been found in earlier research to affect glucose metabolic capacity, resulting in a prolonged lag period. Therefore, we speculated that SpGAT1 influenced glucose consumption rate across SpMIG1. Based on yeast one-hybrid assays and qRT-PCR analyses, SpGAT1 regulated the glyoxylate cycle genes ICL1, ICL2, and pyruvate bypass pathway gene ACS, irrespective of the C/N ratio. SpGAT1 also could bind to the ACAT2 promoter in the low C/N medium and induce sterol ester (SE) accumulation. CONCLUSION Our findings indicated that SpGAT1 positively regulated lipid metabolism in S.podzolica zwy-2-3, but that its regulatory patterns varied depending on the C/N ratio. When the C/N ratio was high, SpGAT1 interacted with SpMIG1 to affect carbon absorption and utilization. SpGAT1 also stimulated lipid accumulation by regulating essential lipid anabolism genes. Our insights might spur more research into how nitrogen and carbon metabolism interact to regulate lipid metabolism.
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Affiliation(s)
- Yulu Ran
- Microbiology and Metabolic Engineering key laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065 People’s Republic of China
| | - Hui Xu
- Microbiology and Metabolic Engineering key laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065 People’s Republic of China
| | - Qingzhuoma Yang
- Microbiology and Metabolic Engineering key laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065 People’s Republic of China
| | - Yi Xu
- Microbiology and Metabolic Engineering key laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065 People’s Republic of China
| | - Huahao Yang
- Microbiology and Metabolic Engineering key laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065 People’s Republic of China
| | - Dairong Qiao
- Microbiology and Metabolic Engineering key laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065 People’s Republic of China
| | - Yi Cao
- Microbiology and Metabolic Engineering key laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065 People’s Republic of China
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Caló G, De Marco MA, Salerno GL, Martínez-Noël GMA. TOR signaling in the green picoalga Ostreococcus tauri. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 323:111390. [PMID: 35868347 DOI: 10.1016/j.plantsci.2022.111390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/29/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Target of rapamycin (TOR) is a master regulator that controls growth and metabolism by integrating external and internal signals. Although there was a great progress in the study of TOR in plants and in the model alga Chlamydomonas, scarce data are available in other green algae. Thus, in this work we studied TOR signaling in Ostreococcus tauri, the smallest free-living eukaryote described to date. This picoalga is particularly important because it has a key site at the base of the green lineage and is part of the marine phytoplankton, contributing to global photosynthesis. We investigated OtTOR complex in silico and experimentally, by using first- and second-generation TOR inhibitors, such as rapamycin and PP242. We analyzed the effect of TOR down-regulation on cell growth and on the accumulation of carbon reserves. The results showed that O. tauri responds to TOR inhibitors more similarly to plants than to Chlamydomonas, being PP242 a valuable tool to study this pathway. Besides, Ottor expression analysis revealed that the kinase is dynamically regulated under nutritional stress. Our data indicate that TOR signaling is conserved in O. tauri and we propose this alga as a good and simple model for studying TOR kinase and its regulation.
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Affiliation(s)
- Gonzalo Caló
- INBIOTEC, Vieytes, 3103, 7600 Mar del Plata, Argentina; FIBA, Vieytes 3103, 7600 Mar del Plata, Argentina
| | - María Agustina De Marco
- INBIOTEC, Vieytes, 3103, 7600 Mar del Plata, Argentina; FIBA, Vieytes 3103, 7600 Mar del Plata, Argentina
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Zhou B, Shima H, Igarashi K, Tanaka K, Imamura S. CmNDB1 and a Specific Domain of CmMYB1 Negatively Regulate CmMYB1-Dependent Transcription of Nitrate Assimilation Genes Under Nitrogen-Repleted Condition in a Unicellular Red Alga. FRONTIERS IN PLANT SCIENCE 2022; 13:821947. [PMID: 35360310 PMCID: PMC8962646 DOI: 10.3389/fpls.2022.821947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 02/07/2022] [Indexed: 06/02/2023]
Abstract
Nitrogen assimilation is an essential process that controls plant growth and development. Plant cells adjust the transcription of nitrogen assimilation genes through transcription factors (TFs) to acclimatize to changing nitrogen levels in nature. However, the regulatory mechanisms of these TFs under nitrogen-repleted (+N) conditions in plant lineages remain largely unknown. Here, we identified a negative domain (ND) of CmMYB1, the nitrogen-depleted (-N)-activated TF, in a unicellular red alga Cyanidioschyzon merolae. The ND deletion changed the localization of CmMYB1 from the cytoplasm to the nucleus, enhanced the binding efficiency of CmMYB1 to promoters of nitrate assimilation genes, and increased the transcripts of nitrate assimilation genes under +N condition. A pull-down assay using an ND-overexpressing strain combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis helped us to screen and identify an unknown-function protein, the CmNDB1. Yeast two-hybrid analysis demonstrated that CmNDB1 interacts with ND. Similar to ND deletion, CmNDB1 deletion also led to the nucleus localization of CmMYB1, enhanced the promoter-binding ratio of CmMYB1 to the promoter regions of nitrate assimilation genes, and increased transcript levels of nitrate assimilation genes under +N condition. Thus, these presented results indicated that ND and CmNDB1 negatively regulate CmMYB1 functions under the +N condition in C. merolae.
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Affiliation(s)
- Baifeng Zhou
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroki Shima
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kazuhiko Igarashi
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- NTT Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, Tokyo, Japan
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Amino Acid Signaling for TOR in Eukaryotes: Sensors, Transducers, and a Sustainable Agricultural fuTORe. Biomolecules 2022; 12:biom12030387. [PMID: 35327579 PMCID: PMC8945916 DOI: 10.3390/biom12030387] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells monitor and regulate metabolism through the atypical protein kinase target of rapamycin (TOR) regulatory hub. TOR is activated by amino acids in animals and fungi through molecular signaling pathways that have been extensively defined in the past ten years. Very recently, several studies revealed that TOR is also acutely responsive to amino acid metabolism in plants, but the mechanisms of amino acid sensing are not yet established. In this review, we summarize these discoveries, emphasizing the diversity of amino acid sensors in human cells and highlighting pathways that are indirectly sensitive to amino acids, i.e., how TOR monitors changes in amino acid availability without a bona fide amino acid sensor. We then discuss the relevance of these model discoveries to plant biology. As plants can synthesize all proteinogenic amino acids from inorganic precursors, we focus on the possibility that TOR senses both organic metabolites and inorganic nutrients. We conclude that an evolutionary perspective on nutrient sensing by TOR benefits both agricultural and biomedical science, contributing to ongoing efforts to generate crops for a sustainable agricultural future.
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12
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Role of Autophagy in Haematococcus lacustris Cell Growth under Salinity. PLANTS 2022; 11:plants11020197. [PMID: 35050085 PMCID: PMC8778389 DOI: 10.3390/plants11020197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/24/2021] [Accepted: 01/08/2022] [Indexed: 11/17/2022]
Abstract
The microalga Haematococcus lacustris (formerly H. pluvialis) is able to accumulate high amounts of the carotenoid astaxanthin in the course of adaptation to stresses like salinity. Technologies aimed at production of natural astaxanthin for commercial purposes often involve salinity stress; however, after a switch to stressful conditions, H. lacustris experiences massive cell death which negatively influences astaxanthin yield. This study addressed the possibility to improve cell survival in H. lacustris subjected to salinity via manipulation of the levels of autophagy using AZD8055, a known inhibitor of TOR kinase previously shown to accelerate autophagy in several microalgae. Addition of NaCl in concentrations of 0.2% or 0.8% to the growth medium induced formation of autophagosomes in H. lacustris, while simultaneous addition of AZD8055 up to a final concentration of 0.2 µM further stimulated this process. AZD8055 significantly improved the yield of H. lacustris cells after 5 days of exposure to 0.2% NaCl. Strikingly, this occurred by acceleration of cell growth, and not by acceleration of aplanospore formation. The level of astaxanthin synthesis was not affected by AZD8055. However, cytological data suggested a role of autophagosomes, lysosomes and Golgi cisternae in cell remodeling during high salt stress.
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Abstract
The target of rapamycin (TOR) kinase is a master regulator that integrates nutrient signals to promote cell growth in all eukaryotes. It is well established that amino acids and glucose are major regulators of TOR signaling in yeast and metazoan, but whether and how TOR responds to carbon availability in photosynthetic organisms is less understood. In this study, we showed that photosynthetic assimilation of CO2 by the Calvin-Benson-Bassham (CBB) cycle regulates TOR activity in the model single-celled microalga Chlamydomonas reinhardtii Stimulation of CO2 fixation boosted TOR activity, whereas inhibition of the CBB cycle and photosynthesis down-regulated TOR. We uncovered a tight link between TOR activity and the endogenous level of a set of amino acids including Ala, Glu, Gln, Leu, and Val through the modulation of CO2 fixation and the use of amino acid synthesis inhibitors. Moreover, the finding that the Chlamydomonas starch-deficient mutant sta6 displayed disproportionate TOR activity and high levels of most amino acids, particularly Gln, further connected carbon assimilation and amino acids to TOR signaling. Thus, our results showed that CO2 fixation regulates TOR signaling, likely through the synthesis of key amino acids.
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15
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Miyagishima SY, Tanaka K. The Unicellular Red Alga Cyanidioschyzon merolae-The Simplest Model of a Photosynthetic Eukaryote. PLANT & CELL PHYSIOLOGY 2021; 62:926-941. [PMID: 33836072 PMCID: PMC8504449 DOI: 10.1093/pcp/pcab052] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/01/2021] [Indexed: 05/13/2023]
Abstract
Several species of unicellular eukaryotic algae exhibit relatively simple genomic and cellular architecture. Laboratory cultures of these algae grow faster than plants and often provide homogeneous cellular populations exposed to an almost equal environment. These characteristics are ideal for conducting experiments at the cellular and subcellular levels. Many microalgal lineages have recently become genetically tractable, which have started to evoke new streams of studies. Among such algae, the unicellular red alga Cyanidioschyzon merolae is the simplest organism; it possesses the minimum number of membranous organelles, only 4,775 protein-coding genes in the nucleus, and its cell cycle progression can be highly synchronized with the diel cycle. These properties facilitate diverse omics analyses of cellular proliferation and structural analyses of the intracellular relationship among organelles. C. merolae cells lack a rigid cell wall and are thus relatively easily disrupted, facilitating biochemical analyses. Multiple chromosomal loci can be edited by highly efficient homologous recombination. The procedures for the inducible/repressive expression of a transgene or an endogenous gene in the nucleus and for chloroplast genome modification have also been developed. Here, we summarize the features and experimental techniques of C. merolae and provide examples of studies using this alga. From these studies, it is clear that C. merolae-either alone or in comparative and combinatory studies with other photosynthetic organisms-can provide significant insights into the biology of photosynthetic eukaryotes.
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Affiliation(s)
- Shin-Ya Miyagishima
- * Corresponding authors: Shin-Ya Miyagishima, E-mail: ; Fax, +81-55-981-9412; Kan Tanaka, E-mail:
| | - Kan Tanaka
- * Corresponding authors: Shin-Ya Miyagishima, E-mail: ; Fax, +81-55-981-9412; Kan Tanaka, E-mail:
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16
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Shi Y, Chen Z, Li Y, Cao X, Yang L, Xu Y, Li Z, He N. Function of ORFC of the polyketide synthase gene cluster on fatty acid accumulation in Schizochytrium limacinum SR21. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:163. [PMID: 34301326 PMCID: PMC8305795 DOI: 10.1186/s13068-021-02014-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND As a potential source of polyunsaturated fatty acids (PUFA), Schizochytrium sp. has been widely used in industry for PUFA production. Polyketide synthase (PKS) cluster is supposed to be the primary way of PUFA synthesis in Schizochytrium sp. As one of three open reading frames (ORF) in the PKS cluster, ORFC plays an essential role in fatty acid biosynthesis. However, the function of domains in ORFC in the fatty acid synthesis of Schizochytrium sp. remained unclear. RESULTS In this study, heterologous expression and overexpression were carried out to study the role of ORFC and its domains in fatty acid accumulation. Firstly, ORFC was heterologously expressed in yeast which increased the PUFA content significantly. Then, the dehydratase (DH) and enoyl reductase (ER) domains located on ORFC were overexpressed in Schizochytrium limacinum SR21, respectively. Fatty acids profile analysis showed that the contents of PUFA and saturated fatty acid were increased in the DH and ER overexpression strains, respectively. This indicated that the DH and ER domains played distinct roles in lipid accumulation. Metabolic and transcriptomic analysis revealed that the pentose phosphate pathway and triacylglycerol biosynthesis were enhanced, while the tricarboxylic acid cycle and fatty acids oxidation were weakened in DH-overexpression strain. However, the opposite effect was found in the ER-overexpression strain. CONCLUSION Therefore, ORFC was required for the biosynthesis of fatty acid. The DH domain played a crucial role in PUFA synthesis, whereas the ER domain might be related to saturated fatty acids (SFA) synthesis in Schizochytrium limacinum SR21. This research explored the role of ORFC in the PKS gene cluster in Schizochytrium limacinum and provided potential genetic modification strategies for improving lipid production and regulating PUFA and SFA content.
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Affiliation(s)
- Yanyan Shi
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Zhen Chen
- College of Life Science, Xinyang Normal University, Xinyang, 464000, China
| | - Yixin Li
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Xingyu Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Yiyuan Xu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Zhipeng Li
- College of Food and Biological Engineering, Jimei University, Xiamen, 361021, China
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
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17
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Pancha I, Takaya K, Tanaka K, Imamura S. The Unicellular Red Alga Cyanidioschyzon merolae, an Excellent Model Organism for Elucidating Fundamental Molecular Mechanisms and Their Applications in Biofuel Production. PLANTS 2021; 10:plants10061218. [PMID: 34203949 PMCID: PMC8232737 DOI: 10.3390/plants10061218] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 11/16/2022]
Abstract
Microalgae are considered one of the best resources for the production of biofuels and industrially important compounds. Various models have been developed to understand the fundamental mechanism underlying the accumulation of triacylglycerols (TAGs)/starch and to enhance its content in cells. Among various algae, the red alga Cyanidioschyzonmerolae has been considered an excellent model system to understand the fundamental mechanisms behind the accumulation of TAG/starch in the microalga, as it has a smaller genome size and various biotechnological methods are available for it. Furthermore, C. merolae can grow and survive under high temperature (40 °C) and low pH (2–3) conditions, where most other organisms would die, thus making it a choice alga for large-scale production. Investigations using this alga has revealed that the target of rapamycin (TOR) kinase is involved in the accumulation of carbon-reserved molecules, TAGs, and starch. Furthermore, detailed molecular mechanisms of the role of TOR in controlling the accumulation of TAGs and starch were uncovered via omics analyses. Based on these findings, genetic engineering of the key gene and proteins resulted in a drastic increment of the amount of TAGs and starch. In addition to these studies, other trials that attempted to achieve the TAG increment in C. merolae have been summarized in this article.
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Affiliation(s)
- Imran Pancha
- Department of Biological Sciences, SRM University-AP, Amaravati, Andhra Pradesh 522502, India
- Correspondence: (I.P.); (S.I.); Tel.: +81-422-59-6179 (S.I.)
| | - Kazuhiro Takaya
- NTT Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, 3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan;
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama-shi, Kanagawa 226-8503, Japan;
| | - Sousuke Imamura
- NTT Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, 3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan;
- Correspondence: (I.P.); (S.I.); Tel.: +81-422-59-6179 (S.I.)
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18
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Chen H, Wang Q. Regulatory mechanisms of lipid biosynthesis in microalgae. Biol Rev Camb Philos Soc 2021; 96:2373-2391. [PMID: 34101323 DOI: 10.1111/brv.12759] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 02/01/2023]
Abstract
Microalgal lipids are highly promising feedstocks for biofuel production. Microalgal lipids, especially triacylglycerol, and practical applications of these compounds have received increasing attention in recent years. For the commercial use of microalgal lipids to be feasible, many fundamental biological questions must be addressed based on detailed studies of algal biology, including how lipid biosynthesis occurs and is regulated. Here, we review the current understanding of microalgal lipid biosynthesis, with a focus on the underlying regulatory mechanisms. We also present possible solutions for overcoming various obstacles to understanding the basic biology of microalgal lipid biosynthesis and the practical application of microalgae-based lipids. This review will provide a theoretical reference for both algal researchers and decision makers regarding the future directions of microalgal research, particularly pertaining to microalgal-based lipid biosynthesis.
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Affiliation(s)
- Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
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19
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Identification of Transcription Factors and the Regulatory Genes Involved in Triacylglycerol Accumulation in the Unicellular Red Alga Cyanidioschyzon merolae. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10050971. [PMID: 34068121 PMCID: PMC8152781 DOI: 10.3390/plants10050971] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/10/2021] [Accepted: 05/10/2021] [Indexed: 12/30/2022]
Abstract
Microalgal triacylglycerols (TAGs) are a good feedstock for liquid biofuel production. Improving the expression and/or function of transcription factors (TFs) involved in TAG accumulation may increase TAG content; however, information on microalgae is still lacking. In this study, 14 TFs in the unicellular red alga Cyanidioschyzon merolae were identified as candidate TFs regulating TAG accumulation using available transcriptome and phosphoproteome data under conditions driving TAG accumulation. To investigate the roles of these TFs, we constructed TF-overexpression strains and analyzed lipid droplet (LD) formation and TAG contents in the cells grown under standard conditions. Based on the results, we identified four TFs involved in LD and TAG accumulation. RNA-Seq analyses were performed to identify genes regulated by the four TFs using each overexpression strain. Among the TAG biosynthesis-related genes, only the gene encoding the endoplasmic reticulum-localized lysophosphatidic acid acyltransferase 1 (LPAT1) was notably increased among the overexpression strains. In the LPAT1 overexpression strain, TAG accumulation was significantly increased compared with the control strain under normal growth conditions. These results indicate that the four TFs positively regulate TAG accumulation by changing their target gene expression in C. merolae.
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20
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Ingargiola C, Turqueto Duarte G, Robaglia C, Leprince AS, Meyer C. The Plant Target of Rapamycin: A Conduc TOR of Nutrition and Metabolism in Photosynthetic Organisms. Genes (Basel) 2020; 11:genes11111285. [PMID: 33138108 PMCID: PMC7694126 DOI: 10.3390/genes11111285] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 12/15/2022] Open
Abstract
Living organisms possess many mechanisms to sense nutrients and favorable conditions, which allow them to grow and develop. Photosynthetic organisms are very diverse, from green unicellular algae to multicellular flowering plants, but most of them are sessile and thus unable to escape from the biotic and abiotic stresses they experience. The Target of Rapamycin (TOR) signaling pathway is conserved in all eukaryotes and acts as a central regulatory hub between growth and extrinsic factors, such as nutrients or stress. However, relatively little is known about the regulations and roles of this pathway in plants and algae. Although some features of the TOR pathway seem to have been highly conserved throughout evolution, others clearly differ in plants, perhaps reflecting adaptations to different lifestyles and the rewiring of this primordial signaling module to adapt to specific requirements. Indeed, TOR is involved in plant responses to a vast array of signals including nutrients, hormones, light, stresses or pathogens. In this review, we will summarize recent studies that address the regulations of TOR by nutrients in photosynthetic organisms, and the roles of TOR in controlling important metabolic pathways, highlighting similarities and differences with the other eukaryotes.
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Affiliation(s)
- Camille Ingargiola
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (C.I.); (G.T.D.); (A.-S.L.)
| | - Gustavo Turqueto Duarte
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (C.I.); (G.T.D.); (A.-S.L.)
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Christophe Robaglia
- Laboratoire de Génétique et Biophysique des Plantes, Faculté des Sciences de Luminy, UMR 7265, CEA, CNRS, BIAM, Aix Marseille Université, 13009 Marseille, France;
| | - Anne-Sophie Leprince
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (C.I.); (G.T.D.); (A.-S.L.)
- Faculté des Sciences et d’Ingénierie, Sorbonne Université, UFR 927, 4 Place Jussieu, 75252 Paris, France
| | - Christian Meyer
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (C.I.); (G.T.D.); (A.-S.L.)
- Correspondence:
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21
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Anzai T, Imamura S, Ishihama A, Shimada T. Expanded roles of pyruvate-sensing PdhR in transcription regulation of the Escherichia coli K-12 genome: fatty acid catabolism and cell motility. Microb Genom 2020; 6. [PMID: 32975502 PMCID: PMC7660256 DOI: 10.1099/mgen.0.000442] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The transcription factor PdhR has been recognized as the master regulator of the pyruvate catabolism pathway in Escherichia coli, including both NAD-linked oxidative decarboxylation of pyruvate to acetyl-CoA by PDHc (pyruvate dehydrogenase complex) and respiratory electron transport of NADH to oxygen by Ndh-CyoABCD enzymes. To identify the whole set of regulatory targets under the control of pyruvate-sensing PdhR, we performed genomic SELEX (gSELEX) screening in vitro. A total of 35 PdhR-binding sites were identified along the E. coli K-12 genome, including previously identified targets. Possible involvement of PdhR in regulation of the newly identified target genes was analysed in detail by gel shift assay, RT-qPCR and Northern blot analysis. The results indicated the participation of PdhR in positive regulation of fatty acid degradation genes and negative regulation of cell mobility genes. In fact, GC analysis indicated an increase in free fatty acids in the mutant lacking PdhR. We propose that PdhR is a bifunctional global regulator for control of a total of 16–23 targets, including not only the genes involved in central carbon metabolism but also some genes for the surrounding pyruvate-sensing cellular pathways such as fatty acid degradation and flagella formation. The activity of PdhR is controlled by pyruvate, the key node between a wide variety of metabolic pathways, including generation of metabolic energy and cell building blocks.
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Affiliation(s)
- Takumi Anzai
- School of Agriculture, Meiji University, Kawasaki, Kanagawa, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Akira Ishihama
- Micro-Nanotechnology Research Center, Hosei University, Koganei, Tokyo, Japan
| | - Tomohiro Shimada
- School of Agriculture, Meiji University, Kawasaki, Kanagawa, Japan
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22
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Pancha I, Chokshi K, Tanaka K, Imamura S. Microalgal Target of Rapamycin (TOR): A Central Regulatory Hub for Growth, Stress Response and Biomass Production. PLANT & CELL PHYSIOLOGY 2020; 61:675-684. [PMID: 32105317 DOI: 10.1093/pcp/pcaa023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
Target of rapamycin (TOR) is an evolutionarily conserved protein kinase that plays an important role in the regulation of cell growth and the sensing of nutrient and energy status in eukaryotes. In yeasts and mammals, the roles of TOR have been very well described and various functions of TOR signaling in plant lineages have also been revealed over the past 20 years. In the case of microalgae, the functions of TOR have been primarily studied in the model green alga Chlamydomonas reinhardtii and were summarized in an earlier single review article. However, the recent development of tools for the functional analysis of TOR has helped to reveal the involvement of TOR in various functions, including autophagy, transcription, translation, accumulation of energy storage molecules, etc., in microalgae. In the present review, we discuss recent novel findings relating to TOR signaling and its roles in microalgae along with relevant information on land plants and also provide details of topics that must be addressed in future studies to reveal how TOR regulates various physiological functions in microalgae.
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Affiliation(s)
- Imran Pancha
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
- Department of Biology, SRM University-AP, Amaravati, Andhra Pradesh 522502, India
| | - Kaumeel Chokshi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
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23
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Kajikawa M, Fukuzawa H. Algal Autophagy Is Necessary for the Regulation of Carbon Metabolism Under Nutrient Deficiency. FRONTIERS IN PLANT SCIENCE 2020; 11:36. [PMID: 32117375 PMCID: PMC7012896 DOI: 10.3389/fpls.2020.00036] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/13/2020] [Indexed: 05/04/2023]
Abstract
Autophagy is a mechanism to recycle intracellular constituents such as amino acids and other carbon- and nitrogen (N)-containing compounds. Although autophagy-related (ATG) genes required for autophagy are encoded by many algal genomes, their functional importance in microalgae in nutrient-deficiency has not been appraised using ATG-defective mutants. Recently, by characterization of an insertional mutant of the ATG8 encoding a ubiquitin-like protein indispensable for autophagosome formation in a green alga Chlamydomonas reinhardtii, we have provided evidence that supports the following notions. ATG8 protein is required for the degradation of lipid droplets and triacylglycerol (TAG) triggered by resupply of N to cell culture in N-deficient conditions. ATG8 protein is also necessary for starch accumulation under phosphorus-deficient conditions. Algal autophagy is not necessary for inheritance of chloroplast and mitochondrial genomes. In this review, we discuss the physiological roles of algal autophagy associated with nutrient deficiency revealed by the genetic and biochemical analyses using disruption mutants and reagents that inhibit the fatty acid biosynthesis and vacuolar H+-ATPase.
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24
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Kokabi K, Gorelova O, Zorin B, Didi-Cohen S, Itkin M, Malitsky S, Solovchenko A, Boussiba S, Khozin-Goldberg I. Lipidome Remodeling and Autophagic Respose in the Arachidonic-Acid-Rich Microalga Lobosphaera incisa Under Nitrogen and Phosphorous Deprivation. FRONTIERS IN PLANT SCIENCE 2020; 11:614846. [PMID: 33329680 PMCID: PMC7728692 DOI: 10.3389/fpls.2020.614846] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/02/2020] [Indexed: 05/09/2023]
Abstract
The green microalga Lobosphaera incisa accumulates triacylglycerols (TAGs) with exceptionally high levels of long-chain polyunsaturated fatty acid (LC-PUFA) arachidonic acid (ARA) under nitrogen (N) deprivation. Phosphorous (P) deprivation induces milder changes in fatty acid composition, cell ultrastructure, and growth performance. We hypothesized that the resource-demanding biosynthesis and sequestration of ARA-rich TAG in lipid droplets (LDs) are associated with the enhancement of catabolic processes, including membrane lipid turnover and autophagic activity. Although this work focuses mainly on N deprivation, a comparative analysis of N and P deprivation responses is included. The results of lipidomic profiling showed a differential impact of N and P deprivation on the reorganization of glycerolipids. The formation of TAG under N deprivation was associated with the enhanced breakdown of chloroplast glycerolipids and the formation of lyso-lipids. N-deprived cells displayed a profound reorganization of cell ultrastructure, including internalization of cellular material into autophagic vacuoles, concomitant with the formation of LDs, while P-deprived cells showed better cellular ultrastructural integrity. The expression of the hallmark autophagy protein ATG8 and the major lipid droplet protein (MLDP) genes were coordinately upregulated, but to different extents under either N or P deprivation. The expression of the Δ5-desaturase gene, involved in the final step of ARA biosynthesis, was coordinated with ATG8 and MLDP, exclusively under N deprivation. Concanamycin A, the inhibitor of vacuolar proteolysis and autophagic flux, suppressed growth and enhanced levels of ATG8 and TAG in N-replete cells. The proportions of ARA in TAG decreased with a concomitant increase in oleic acid under both N-replete and N-deprived conditions. The photosynthetic apparatus's recovery from N deprivation was impaired in the presence of the inhibitor, along with the delayed LD degradation. The GFP-ATG8 processing assay showed the release of free GFP in N-replete and N-deprived cells, supporting the existence of autophagic flux. This study provides the first insight into the homeostatic role of autophagy in L. incisa and points to a possible metabolic link between autophagy and ARA-rich TAG biosynthesis.
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Affiliation(s)
- Kamilya Kokabi
- The Albert Katz International School for Desert Studies, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, The J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Olga Gorelova
- Department of Bioengineering, Faculty of Biology, Moscow State University, GSP-1, Moscow, Russia
| | - Boris Zorin
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, The J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Shoshana Didi-Cohen
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, The J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Maxim Itkin
- Metabolic Profiling Unit, Life Science Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Sergey Malitsky
- Metabolic Profiling Unit, Life Science Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Alexei Solovchenko
- Department of Bioengineering, Faculty of Biology, Moscow State University, GSP-1, Moscow, Russia
- Institute of Natural Sciences, Derzhavin Tambov State University, Tambov, Russia
- Peoples Friendship University of Russia (RUDN University), Moscow, Russia
| | - Sammy Boussiba
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, The J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Inna Khozin-Goldberg
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, The J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
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Mubeen U, Giavalisco P, Caldana C. TOR inhibition interrupts the metabolic homeostasis by shifting the carbon-nitrogen balance in Chlamydomonas reinhardtii. PLANT SIGNALING & BEHAVIOR 2019; 14:1670595. [PMID: 31583958 PMCID: PMC6804693 DOI: 10.1080/15592324.2019.1670595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 09/13/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
The allocation of nutrient resources to growth and metabolism is an essential function for controlling biomass accumulation in photoautotrophic organisms. One essential protein complex involved in this process is the target of rapamycin (TOR) kinase. It has been shown that the inhibition of TOR leads to a considerable upsurge in the amino acid levels. This molecular phenotype relies mainly on the availability of light, carbon (C) and nitrogen (N). To validate the time-resolved response of C and N metabolites, we used a targeted gas chromatography mass spectrometery (GC-MS)-based metabolomic approach, where we examined the response of Chlamydomonas reinhardtii upon TOR inhibition under C-limited condition, namely extended darkness. Contrary to C-supplemented conditions, the rapid increase in the amino acid levels is suppressed almost completely 4 h after TOR inhibition, confirming that C supply is essential to raise the amino acid levels mediated by their de novo synthesis. An exception to this observation was the levels of aspartate, which is presumably synthesized via the anaplerotic pathway. In agreement with previous reports, TOR repression, under these C-limited conditions, leads to a significant reduction in the C/N ratio, corroborating with the crucial role of the pathway in maintaining the metabolic balance of the cells and consequently propelling growth.
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Affiliation(s)
- Umarah Mubeen
- Molecular Physiology Department, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | | | - Camila Caldana
- Molecular Physiology Department, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
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Liu N, Yun Y, Yin Y, Hahn M, Ma Z, Chen Y. Lipid droplet biogenesis regulated by the FgNem1/Spo7-FgPah1 phosphatase cascade plays critical roles in fungal development and virulence in Fusarium graminearum. THE NEW PHYTOLOGIST 2019; 223:412-429. [PMID: 30767239 DOI: 10.1111/nph.15748] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 02/08/2019] [Indexed: 06/09/2023]
Abstract
Lipid droplets (LDs) control lipid metabolism in eukaryotic cells in general. However, the biogenesis regulation and biological functions of LDs are largely unknown in pathogenic fungi. Rapamycin treatment results in a significant increase of LD biogenesis in Fusarium graminearum. Molecular mechanisms of the target of rapamycin (TOR) pathway in regulating LD biogenesis and the functions of LD in virulence of F. graminearum were investigated in depth by combining genetic, cytological and phenotypic strategies. TOR in Fusarium graminearum (FgTOR) inhibition by rapamycin induces LD biogenesis through the FgPpg1/Sit4 signaling branch. FgPpg1 promotes phosphorylation of protein phosphatase FgNem1 by the protein kinase FgCak1. The phosphorylated FgNem1 dephosphorylates the phosphatidate phosphatase FgPah1. Dephosphorylated FgPah1 is active and stimulates LD biogenesis. Moreover, deletion of FgNem1/Spo7 or FgPah1 leads to serious defects in vegetative growth, sexual development and virulence. The results of this study provide novel insights into the regulatory mechanism and biological functions of the LDs in the devastating pathogenic fungus F. graminearum.
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Affiliation(s)
- Na Liu
- State Key Laboratory of Rice Biology, and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Yingzi Yun
- State Key Laboratory of Rice Biology, and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Yanni Yin
- State Key Laboratory of Rice Biology, and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Matthias Hahn
- Department of Biology, Kaiserslautern University, 67663, Kaiserslautern, Germany
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Yun Chen
- State Key Laboratory of Rice Biology, and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
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Prioretti L, Carriere F, Field B, Avilan L, Montané MH, Menand B, Gontero B. Targeting TOR signaling for enhanced lipid productivity in algae. Biochimie 2019; 169:12-17. [PMID: 31265860 DOI: 10.1016/j.biochi.2019.06.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/26/2019] [Indexed: 01/21/2023]
Abstract
Microalgae can produce large quantities of triacylglycerols (TAGs) and other neutral lipids that are suitable for making biofuels and as feedstocks for green chemistry. However, TAGs accumulate under stress conditions that also stop growth, leading to a trade-off between biomass production and TAG yield. Recently, in the model marine diatom Phaeodactylum tricornutum it was shown that inhibition of the target of rapamycin (TOR) kinase boosts lipid productivity by promoting TAG production without stopping growth. We believe that basic knowledge in this emerging field is required to develop innovative strategies to improve neutral lipid accumulation in oleaginous microalgae. In this minireview, we discuss current research on the TOR signaling pathway with a focus on its control on lipid homeostasis. We first provide an overview of the well characterized roles of TOR in mammalian lipogenesis, adipogenesis and lipolysis. We then present evidence of a role for TOR in controlling TAG accumulation in microalgae, and draw parallels between the situation in animals, plants and microalgae to propose a model of TOR signaling for TAG accumulation in microalgae.
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Affiliation(s)
- Laura Prioretti
- Aix Marseille Univ, CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, 13402, Marseille, Cedex 09, France
| | - Frédéric Carriere
- Aix Marseille Univ, CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, 13402, Marseille, Cedex 09, France
| | - Ben Field
- Aix Marseille Univ, CEA, CNRS, UMR 7265 BIAM, 163 Avenue de Luminy, 13288, Marseille, France
| | - Luisana Avilan
- Aix Marseille Univ, CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, 13402, Marseille, Cedex 09, France
| | - Marie-Hélène Montané
- Aix Marseille Univ, CEA, CNRS, UMR 7265 BIAM, 163 Avenue de Luminy, 13288, Marseille, France
| | - Benoît Menand
- Aix Marseille Univ, CEA, CNRS, UMR 7265 BIAM, 163 Avenue de Luminy, 13288, Marseille, France.
| | - Brigitte Gontero
- Aix Marseille Univ, CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, 13402, Marseille, Cedex 09, France.
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Kokabi K, Gorelova O, Ismagulova T, Itkin M, Malitsky S, Boussiba S, Solovchenko A, Khozin-Goldberg I. Metabolomic foundation for differential responses of lipid metabolism to nitrogen and phosphorus deprivation in an arachidonic acid-producing green microalga. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 283:95-115. [PMID: 31128719 DOI: 10.1016/j.plantsci.2019.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/05/2019] [Accepted: 02/11/2019] [Indexed: 05/08/2023]
Abstract
The green oleaginous microalga Lobosphaera incisa accumulates storage lipids triacylglycerols (TAG) enriched in the long-chain polyunsaturated fatty acid arachidonic acid under nitrogen (N) deprivation. In contrast, under phosphorous (P) deprivation, the production of the monounsaturated oleic acid prevails. We compared physiological responses, ultrastructural, and metabolic consequences of L. incisa acclimation to N and P deficiency to provide novel insights into the key determinants of ARA accumulation. Differential responses to nutrient deprivation on growth performance, carbon-to-nitrogen stoichiometry, membrane lipid composition and TAG accumulation were demonstrated. Ultrastructural analyses suggested a dynamic role for vacuoles in sustaining cell homeostasis under conditions of different nutrient availability and their involvement in autophagy in L. incisa. Paralleling ARA-rich TAG accumulation in lipid droplets, N deprivation triggered intensive chloroplast dismantling and promoted catabolic processes. Metabolome analysis revealed depletion of amino acids and pyrimidines, and repression of numerous biosynthetic hubs to favour TAG biosynthesis under N deprivation. Under P deprivation, despite the relatively low growth penalties, the presence of the endogenous P reserves and the characteristic lipid remodelling, metabolic signatures of energy deficiency were revealed. Metabolome adjustments to P deprivation included depletion in ATP and phosphorylated nucleotides, increased levels of TCA-cycle intermediates and osmoprotectants. We conclude that characteristic cellular and metabolome adjustments tailor the adaptive responses of L. incisa to N and P deprivation modulating its LC-PUFA production.
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Affiliation(s)
- Kamilya Kokabi
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, The J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel
| | - Olga Gorelova
- Department of Bioengineering, Faculty of Biology, Moscow State University, GSP-1, Moscow, 119234, Russia
| | - Tatiana Ismagulova
- Department of Bioengineering, Faculty of Biology, Moscow State University, GSP-1, Moscow, 119234, Russia
| | - Maxim Itkin
- Metabolic Profiling Unit, Life Science Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Sergey Malitsky
- Metabolic Profiling Unit, Life Science Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Sammy Boussiba
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, The J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel
| | - Alexei Solovchenko
- Department of Bioengineering, Faculty of Biology, Moscow State University, GSP-1, Moscow, 119234, Russia; Peoples Friendship University of Russia (RUDN University), Moscow, 117198, Russia
| | - Inna Khozin-Goldberg
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, The J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel.
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Pancha I, Tanaka K, Imamura S. Overexpression of a glycogenin, CmGLG2, enhances floridean starch accumulation in the red alga Cyanidioschyzon merolae. PLANT SIGNALING & BEHAVIOR 2019; 14:1596718. [PMID: 30938572 PMCID: PMC6546146 DOI: 10.1080/15592324.2019.1596718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/10/2019] [Accepted: 03/12/2019] [Indexed: 06/09/2023]
Abstract
Microalgae accumulate energy-reserved molecules, such as triacylglycerol and carbohydrates, which are suitable feedstocks for renewable energies such as biodiesel and bioethanol. However, the molecular mechanisms behind the microalgae accumulating these molecules require further elucidation. Recently, we have reported that the target of rapamycin (TOR)-signaling is a major pathway to regulate floridean starch synthesis by changing the phosphorylation status of CmGLG1, a glycogenin generally required for the initiation of starch/glycogen synthesis, in the unicellular red alga Cyanidioschyzon merolae. In the present study, we confirmed that another glycogenin, CmGLG2, is also involved in the floridean starch synthesis in this alga, since the CmGLG2 overexpression resulted in a two-fold higher floridean starch content in the cell. The results indicate that both glycogenin isoforms play an important role in floridean starch synthesis in C. merolae, and would be a potential target for improvement of floridean starch production in microalgae.
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Affiliation(s)
- Imran Pancha
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
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30
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Li L, Zhu T, Song Y, Luo X, Feng L, Zhuo F, Li F, Ren M. Functional Characterization of Target of Rapamycin Signaling in Verticillium dahliae. Front Microbiol 2019; 10:501. [PMID: 30918504 PMCID: PMC6424901 DOI: 10.3389/fmicb.2019.00501] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 02/27/2019] [Indexed: 12/11/2022] Open
Abstract
More than 200 plants have been suffering from Verticillium wilt caused by Verticillium dahliae (V. dahliae) across the world. The target of rapamycin (TOR) is a lethal gene and controls cell growth and development in various eukaryotes, but little is known about TOR signaling in V. dahliae. Here, we found that V. dahliae strain is hypersensitive to rapamycin in the presence of rapamycin binding protein VdFKBP12 while the deletion mutant aaavdfkbp12 is insensitive to rapamycin. Heterologous expressing VdFKBP12 in Arabidopsis conferred rapamycin sensitivity, indicating that VdFKBP12 can bridge the interaction between rapamycin and TOR across species. The key across species of TOR complex 1 (TORC1) and TORC2 have been identified in V. dahliae, suggesting that TOR signaling pathway is evolutionarily conserved in eukaryotic species. Furthermore, the RNA-seq analysis showed that ribosomal biogenesis, RNA polymerase II transcription factors and many metabolic processes were significantly suppressed in rapamycin treated cells of V. dahliae. Importantly, transcript levels of genes associated with cell wall degrading enzymes (CWEDs) were dramatically down-regulated in TOR-inhibited cells. Further infection assay showed that the pathogenicity of V. dahliae and occurrence of Verticillium wilt can be blocked in the presence of rapamycin. These observations suggested that VdTOR is a key target of V. dahliae for controlling and preventing Verticillium wilt in plants.
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Affiliation(s)
- Linxuan Li
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Tingting Zhu
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Yun Song
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China.,National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Xiumei Luo
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Li Feng
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Fengping Zhuo
- School of Life Sciences, Chongqing University, Chongqing, China.,School of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, China
| | - Fuguang Li
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China.,National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Maozhi Ren
- School of Life Sciences, Chongqing University, Chongqing, China
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31
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Identification of a chloroplast fatty acid exporter protein, CmFAX1, and triacylglycerol accumulation by its overexpression in the unicellular red alga Cyanidioschyzon merolae. ALGAL RES 2019. [DOI: 10.1016/j.algal.2018.101396] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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32
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Pancha I, Shima H, Higashitani N, Igarashi K, Higashitani A, Tanaka K, Imamura S. Target of rapamycin-signaling modulates starch accumulation via glycogenin phosphorylation status in the unicellular red alga Cyanidioschyzon merolae. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 97:485-499. [PMID: 30351485 DOI: 10.1111/tpj.14136] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 09/23/2018] [Accepted: 10/15/2018] [Indexed: 06/08/2023]
Abstract
The target of rapamycin (TOR) signaling pathway is involved in starch accumulation in various eukaryotic organisms; however, the molecular mechanism behind this phenomenon in eukaryotes has not been elucidated. We report a regulatory mechanism of starch accumulation by TOR in the unicellular red alga, Cyanidioschyzon merolae. The starch content in C. merolae after TOR-inactivation by rapamycin, a TOR-specific inhibitor, was increased by approximately 10-fold in comparison with its drug vehicle, dimethyl sulfoxide. However, our previous transcriptome analysis showed that the expression level of genes related to carbohydrate metabolism was unaffected by rapamycin, indicating that starch accumulation is regulated at post-transcriptional levels. In this study, we performed a phosphoproteome analysis using liquid chromatography-tandem mass spectrometry to investigate potential post-transcriptional modifications, and identified 52 proteins as candidate TOR substrates. Among the possible substrates, we focused on the function of CmGLG1, because its phosphorylation at the Ser613 residue was decreased after rapamycin treatment, and overexpression of CmGLG1 resulted in a 4.7-fold higher starch content. CmGLG1 is similar to the priming protein, glycogenin, which is required for the initiation of starch/glycogen synthesis, and a budding yeast complementation assay demonstrated that CmGLG1 can functionally substitute for glycogenin. We found an approximately 60% reduction in the starch content in a phospho-mimicking CmGLG1 overexpression strain, in which Ser613 was substituted with aspartic acid, in comparison with the wild-type CmGLG1 overexpression cells. Our results indicate that TOR modulates starch accumulation by changing the phosphorylation status of the CmGLG1 Ser613 residue in C. merolae.
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Affiliation(s)
- Imran Pancha
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - Hiroki Shima
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Aoba-ku, Sendai, 980-8575, Japan
| | - Nahoko Higashitani
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Kazuhiko Igarashi
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Aoba-ku, Sendai, 980-8575, Japan
| | - Atsushi Higashitani
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
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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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Werth EG, McConnell EW, Couso Lianez I, Perrine Z, Crespo JL, Umen JG, Hicks LM. Investigating the effect of target of rapamycin kinase inhibition on the Chlamydomonas reinhardtii phosphoproteome: from known homologs to new targets. THE NEW PHYTOLOGIST 2019; 221:247-260. [PMID: 30040123 DOI: 10.1111/nph.15339] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/11/2018] [Indexed: 05/20/2023]
Abstract
Target of rapamycin (TOR) kinase is a conserved regulator of cell growth whose activity is modulated in response to nutrients, energy and stress. Key proteins involved in the pathway are conserved in the model photosynthetic microalga Chlamydomonas reinhardtii, but the substrates of TOR kinase and downstream signaling network have not been elucidated. Our study provides a new resource for investigating the phosphorylation networks governed by the TOR kinase pathway in Chlamydomonas. We used quantitative phosphoproteomics to investigate the effects of inhibiting Chlamydomonas TOR kinase on dynamic protein phosphorylation. Wild-type and AZD-insensitive Chlamydomonas strains were treated with TOR-specific chemical inhibitors (rapamycin, AZD8055 and Torin1), after which differentially affected phosphosites were identified. Our quantitative phosphoproteomic dataset comprised 2547 unique phosphosites from 1432 different proteins. Inhibition of TOR kinase caused significant quantitative changes in phosphorylation at 258 phosphosites, from 219 unique phosphopeptides. Our results include Chlamydomonas homologs of TOR signaling-related proteins, including a site on RPS6 with a decrease in phosphorylation. Additionally, phosphosites on proteins involved in translation and carotenoid biosynthesis were identified. Follow-up experiments guided by these phosphoproteomic findings in lycopene beta/epsilon cyclase showed that carotenoid levels are affected by TORC1 inhibition and carotenoid production is under TOR control in algae.
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Affiliation(s)
- Emily G Werth
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Evan W McConnell
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Inmaculada Couso Lianez
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Avda. Américo Vespucio 49, 41092, Sevilla, Spain
| | - Zoee Perrine
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - Jose L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Avda. Américo Vespucio 49, 41092, Sevilla, Spain
| | - James G Umen
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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35
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Takeuchi T, Benning C. Nitrogen-dependent coordination of cell cycle, quiescence and TAG accumulation in Chlamydomonas. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:292. [PMID: 31890020 PMCID: PMC6927116 DOI: 10.1186/s13068-019-1635-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 12/12/2019] [Indexed: 05/07/2023]
Abstract
Microalgae hold great promises as sustainable cellular factories for the production of alternative fuels, feeds, and biopharmaceuticals for human health. While the biorefinery approach for fuels along with the coproduction of high-value compounds with industrial, therapeutic, or nutraceutical applications have the potential to make algal biofuels more economically viable, a number of challenges continue to hamper algal production systems at all levels. One such hurdle includes the metabolic trade-off often observed between the increased yields of desired products, such as triacylglycerols (TAG), and the growth of an organism. Initial genetic engineering strategies to improve lipid productivity in microalgae, which focused on overproducing the enzymes involved in fatty acid and TAG biosynthesis or inactivating competing carbon (C) metabolism, have seen some successes albeit at the cost of often greatly reduced biomass. Emergent approaches that aim at modifying the dynamics of entire metabolic pathways by engineering of pertinent transcription factors or signaling networks appear to have successfully achieved a balance between growth and neutral lipid accumulation. However, the biological knowledge of key signaling networks and molecular components linking these two processes is still incomplete in photosynthetic eukaryotes, making it difficult to optimize metabolic engineering strategies for microalgae. Here, we focus on nitrogen (N) starvation of the model green microalga, Chlamydomonas reinhardtii, to present the current understanding of the nutrient-dependent switch between proliferation and quiescence, and the drastic reprogramming of metabolism that results in the storage of C compounds following N starvation. We discuss the potential components mediating the transcriptional repression of cell cycle genes and the establishment of quiescence in Chlamydomonas, and highlight the importance of signaling pathways such as those governed by the target of rapamycin (TOR) and sucrose nonfermenting-related (SnRK) kinases in the coordination of metabolic status with cellular growth. A better understanding of how the cell division cycle is regulated in response to nutrient scarcity and of the signaling pathways linking cellular growth to energy and lipid homeostasis, is essential to improve the prospects of biofuels and biomass production in microalgae.
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Affiliation(s)
- Tomomi Takeuchi
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 USA
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
| | - Christoph Benning
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 USA
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824 USA
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Takemura T, Imamura S, Kobayashi Y, Tanaka K. Construction of a Selectable Marker Recycling System and the Use in Epitope Tagging of Multiple Nuclear Genes in the Unicellular Red Alga Cyanidioschyzon merolae. PLANT & CELL PHYSIOLOGY 2018; 59:2308-2316. [PMID: 30099537 DOI: 10.1093/pcp/pcy156] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 07/30/2018] [Indexed: 06/08/2023]
Abstract
The nuclear genome of the unicellular red alga Cyanidioschyzon merolae can be modified by homologous recombination with exogenously introduced DNA. However, it is presently difficult to modify multiple chromosome loci because of the limited number of available positive selectable markers. In this study, we constructed a modified URA5.3 gene (URA5.3T), which can be repeatedly used for nuclear genome transformation, as well as two plasmid vectors for 3× FLAG- or 3× Myc-epitope tagging of nuclear-encoded proteins using URA5.3T. In the URA5.3T marker, the promoter region and open reading frame were located between directly repeated URA5.3 terminator sequences, and the URA5.3 gene can be eliminated by 5-fluoroorotic acid selection through homologous recombination. To demonstrate the utility of the constructed system, a 3× FLAG-tag and 3× Myc-tag were introduced at the C-termini of two of the six Rab proteins in C. merolae, CmRab18 and CmRab7, respectively, and the differential expression levels were successfully monitored by immunoblot analysis using these epitope tags. The URA5.3T marker's introduction and elimination cycle can be repeated. Thus, we have constructed a marker recycling system for C. merolae nuclear transformation. A novel procedure to obtain a high plating efficiency of C. merolae cells on solid gellan gum plates is also presented.
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Affiliation(s)
- Tokiaki Takemura
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
| | - Yuki Kobayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
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Accelerated triacylglycerol production without growth inhibition by overexpression of a glycerol-3-phosphate acyltransferase in the unicellular red alga Cyanidioschyzon merolae. Sci Rep 2018; 8:12410. [PMID: 30120352 PMCID: PMC6098107 DOI: 10.1038/s41598-018-30809-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/04/2018] [Indexed: 12/14/2022] Open
Abstract
Microalgae accumulate triacylglycerols (TAGs), a promising feedstock for biodiesel production, under unfavorable environmental or stress conditions for their growth. Our previous analyses revealed that only transcripts of CmGPAT1 and CmGPAT2, both encoding glycerol-3-phosphate acyltransferase, were increased among fatty acid and TAG synthesis genes under TAG accumulation conditions in the red alga Cyanidioschyzon merolae. In this study, to investigate the role of these proteins in TAG accumulation in C. merolae, we constructed FLAG-fused CmGPAT1 and CmGPAT2 overexpression strains. We found that CmGPAT1 overexpression resulted in marked accumulation of TAG even under normal growth conditions, with the maximum TAG productivity increased 56.1-fold compared with the control strain, without a negative impact on algal growth. The relative fatty acid composition of 18:2 in the TAGs and the sn-1/sn-3 positions were significantly increased compared with the control strain, suggesting that CmGPAT1 had a substrate preference for 18:2. Immunoblot analysis after cell fractionation and immunostaining analysis demonstrated that CmGPAT1 localizes in the endoplasmic reticulum (ER). These results indicate that the reaction catalyzed by the ER-localized CmGPAT1 is a rate-limiting step for TAG synthesis in C. merolae, and would be a potential target for improvement of TAG productivity in microalgae.
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Imamura S, Nomura Y, Takemura T, Pancha I, Taki K, Toguchi K, Tozawa Y, Tanaka K. The checkpoint kinase TOR (target of rapamycin) regulates expression of a nuclear-encoded chloroplast RelA-SpoT homolog (RSH) and modulates chloroplast ribosomal RNA synthesis in a unicellular red alga. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:327-339. [PMID: 29441718 DOI: 10.1111/tpj.13859] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/11/2017] [Accepted: 01/23/2018] [Indexed: 05/14/2023]
Abstract
Chloroplasts are plant organelles that carry out oxygenic photosynthesis. Chloroplast biogenesis depends upon chloroplast ribosomes and their translational activity. However, regulation of chloroplast ribosome biogenesis remains an important unanswered question. In this study, we found that inhibition of target of rapamycin (TOR), a general eukaryotic checkpoint kinase, results in a decline in chloroplast ribosomal RNA (rRNA) transcription in the unicellular red alga, Cyanidioschyzon merolae. Upon TOR inhibition, transcriptomics and other analyses revealed increased expression of a nuclear-encoded chloroplast RelA-SpoT homolog (RSH) gene (CmRSH4b), which encodes a homolog of the guanosine 3'-diphosphate 5'-diphosphate (ppGpp) synthetases that modulate rRNA synthesis in bacteria. Using an Escherichia coli mutant lacking ppGpp, CmRSH4b was demonstrated to have ppGpp synthetase activity. Expression analysis of a green fluorescent protein-fused protein indicated that CmRSH4b localizes to the chloroplast, and overexpression of the CmRSH4b gene resulted in a decrease of chloroplast rRNA synthesis concomitant with growth inhibition and reduction of chloroplast size. Biochemical analyses using C. merolae cell lysates or purified recombinant proteins revealed that ppGpp inhibits bacteria-type RNA polymerase-dependent chloroplast rRNA synthesis as well as a chloroplast guanylate kinase. These results suggest that CmRSH4b-dependent ppGpp synthesis in chloroplasts is an important regulator of chloroplast rRNA transcription. Nuclear and mitochondrial rRNA transcription were both reduced by TOR inhibition, suggesting that the biogeneses of the three independent ribosome systems are interconnected by TOR in plant cells.
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Affiliation(s)
- Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - Yuhta Nomura
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Tokiaki Takemura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - Imran Pancha
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - Keiko Taki
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - Kazuki Toguchi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - Yuzuru Tozawa
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
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Toyoshima M, Sato N. Optimization of triacylglycerol and starch production in Chlamydomonas debaryana NIES-2212 with regard to light intensity and CO2 concentration. MICROBIOLOGY-SGM 2018; 164:359-368. [PMID: 29458672 DOI: 10.1099/mic.0.000603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Triacylglycerol (TAG) and starch produced by micro-algae are potential sources of biofuel. Our previous studies showed that the unicellular green alga, Chlamydomonas debaryana NIES-2212, which is a rare species of Chlamydomonas that possesses phosphatidylcholine (PC), is a seed organism for the development of biofuel producers. This alga accumulates large amounts of TAG and starch under completely photo-autotrophic conditions during stationary phase without nutrient deprivation. The present study was performed to optimize the growth conditions of this alga with regard to light intensity and CO2 concentration to improve the efficiency of TAG and starch production. The growth rate of C. debaryana was greater at higher light intensity, although there was no significant difference in the final cell density of the culture. The highest contents of TAG and starch, approximately 200 fmol cell-1 and 600 pg cell-1, respectively, were achieved with a light intensity of 200 µmol m-2 s-1 bubbled with air containing 5.0 % CO2. These results suggest that optimization of light intensity and CO2 concentration can enhance the productivity of TAG and starch by C. debaryana NIES-2212.
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Affiliation(s)
- Masakazu Toyoshima
- Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo, Tokyo 153-8902, Japan.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 102-0076, Japan.,Present address: Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Naoki Sato
- Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo, Tokyo 153-8902, Japan.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 102-0076, Japan
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40
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Jüppner J, Mubeen U, Leisse A, Caldana C, Wiszniewski A, Steinhauser D, Giavalisco P. The target of rapamycin kinase affects biomass accumulation and cell cycle progression by altering carbon/nitrogen balance in synchronized Chlamydomonas reinhardtii cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:355-376. [PMID: 29172247 DOI: 10.1111/tpj.13787] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/31/2017] [Accepted: 11/15/2017] [Indexed: 05/19/2023]
Abstract
Several metabolic processes tightly regulate growth and biomass accumulation. A highly conserved protein complex containing the target of rapamycin (TOR) kinase is known to integrate intra- and extracellular stimuli controlling nutrient allocation and hence cellular growth. Although several functions of TOR have been described in various heterotrophic eukaryotes, our understanding lags far behind in photosynthetic organisms. In the present investigation, we used the model alga Chlamydomonas reinhardtii to conduct a time-resolved analysis of molecular and physiological features throughout the diurnal cycle after TOR inhibition. Detailed examination of the cell cycle phases revealed that growth is not only repressed by 50%, but also that significant, non-linear delays in the progression can be observed. By using metabolomics analysis, we elucidated that the growth repression was mainly driven by differential carbon partitioning between anabolic and catabolic processes. Accordingly, the time-resolved analysis illustrated that metabolic processes including amino acid-, starch- and triacylglycerol synthesis, as well RNA degradation, were redirected within minutes of TOR inhibition. Here especially the high accumulation of nitrogen-containing compounds indicated that an active TOR kinase controls the carbon to nitrogen balance of the cell, which is responsible for biomass accumulation, growth and cell cycle progression.
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Affiliation(s)
- Jessica Jüppner
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Umarah Mubeen
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Andrea Leisse
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
- Brazilian Bioethanol Science and Technology Laboratory/CNPEM, Rua Giuseppe Máximo Scolfano 10000, 13083-970, Campinas, Brazil
| | - Andrew Wiszniewski
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Dirk Steinhauser
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Patrick Giavalisco
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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Harchouni S, Field B, Menand B. AC-202, a highly effective fluorophore for the visualization of lipid droplets in green algae and diatoms. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:120. [PMID: 29713379 PMCID: PMC5913787 DOI: 10.1186/s13068-018-1117-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 04/12/2018] [Indexed: 05/14/2023]
Abstract
BACKGROUND Lipid-specific live cell dyes are an important tool for the study of algal lipid metabolism, the monitoring of lipid production, and the identification of algal strains with high lipid yields. Nile Red and BODIPY have emerged as the principal dyes for these purposes. However, they suffer from a number of shortcomings including for specificity, penetration, interference from chlorophyll autofluorescence, and incompatibility with widely used genetically encoded reporters in the green and blue regions of the spectrum such as the green fluorescent protein and the red fluorescent protein. RESULTS We tested a new blue fluorescent dye, AC-202, in both the green algae Chlamydomonas reinhardtii and the pennate diatom Phaeodactylum tricornutum. We show that AC-202 is effective in both algae and that after minimal sample preparation, it can label lipid droplets induced by nitrogen starvation or by inhibitors of the TOR (target of rapamycin) kinase. We found that AC-202 benefits from a low background signal and is therefore more sensitive than BODIPY for semiquantitative in vivo fluorescence measurements. Finally, a co-staining experiment indicated that AC-202 can be used for multicolor imaging in combination with both red and green fluorophores. CONCLUSIONS AC-202 is an alternative and highly effective fluorophore for algal research that resolves drawbacks encountered with other neutral lipid dyes. AC-202 can be used to rapidly and sensitively visualize lipid droplets, and will contribute to the identification of metabolic and signaling pathways involved in lipid droplet formation, monitoring lipid production, and in the development of screens for algal strains suitable for biofuel production.
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Affiliation(s)
- Seddik Harchouni
- Aix Marseille Univ, CEA, CNRS, UMR7265 BVME, 13009 Marseille, France
| | - Ben Field
- Aix Marseille Univ, CEA, CNRS, UMR7265 BVME, 13009 Marseille, France
| | - Benoît Menand
- Aix Marseille Univ, CEA, CNRS, UMR7265 BVME, 13009 Marseille, France
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42
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Roustan V, Weckwerth W. Quantitative Phosphoproteomic and System-Level Analysis of TOR Inhibition Unravel Distinct Organellar Acclimation in Chlamydomonas reinhardtii. FRONTIERS IN PLANT SCIENCE 2018; 9:1590. [PMID: 30546371 PMCID: PMC6280106 DOI: 10.3389/fpls.2018.01590] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 10/15/2018] [Indexed: 05/13/2023]
Abstract
Rapamycin is an inhibitor of the evolutionary conserved Target of Rapamycin (TOR) kinase which promotes and coordinates translation with cell growth and division. In heterotrophic organisms, TOR regulation is based on intra- and extracellular stimuli such as amino acids level and insulin perception. However, how plant TOR pathways have evolved to integrate plastid endosymbiosis is a remaining question. Despite the close association of the TOR signaling with the coordination between protein turn-over and growth, proteome and phosphoproteome acclimation to a rapamycin treatment have not yet been thoroughly investigated in Chlamydomonas reinhardtii. In this study, we have used in vivo label-free phospho-proteomic analysis to profile both protein and phosphorylation changes at 0, 24, and 48 h in Chlamydomonas cells treated with rapamycin. Using multivariate statistics we highlight the impact of TOR inhibition on both the proteome and the phosphoproteome. Two-way ANOVA distinguished differential levels of proteins and phosphoproteins in response either to culture duration and rapamycin treatment or combined effects. Finally, protein-protein interaction networks and functional enrichment analysis underlined the relation between plastid and mitochondrial metabolism. Prominent changes of proteins involved in sulfur, cysteine, and methionine as well as nucleotide metabolism on the one hand, and changes in the TCA cycle on the other highlight the interplay of chloroplast and mitochondria metabolism. Furthermore, TOR inhibition revealed changes in the endomembrane trafficking system. Phosphoproteomics data, on the other hand, highlighted specific differentially regulated phosphorylation sites for calcium-regulated protein kinases as well as ATG7, S6K, and PP2C. To conclude we provide a first combined Chlamydomonas proteomics and phosphoproteomics dataset in response to TOR inhibition, which will support further investigations.
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Affiliation(s)
- Valentin Roustan
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Wolfram Weckwerth
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
- Vienna Metabolomics Center (VIME), University of Vienna, Vienna, Austria
- *Correspondence: Wolfram Weckwerth,
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Wang G, Li D, Miao Z, Zhang S, Liang W, Liu L. Comparative transcriptome analysis reveals multiple functions for Mhy1p in lipid biosynthesis in the oleaginous yeast Yarrowia lipolytica. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1863:81-90. [PMID: 29055818 DOI: 10.1016/j.bbalip.2017.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/24/2017] [Accepted: 10/17/2017] [Indexed: 02/07/2023]
Abstract
Yarrowia lipolytica is considered as a promising microbial cell factory for bio-oil production due to its ability to accumulate a large amount of lipid. However, the regulation of lipid metabolism in this oleaginous yeast is elusive. In this study, the MHY1 gene was disrupted, and 43.1% (w/w) intracellular oil based on cell dry weight was obtained from the disruptant M-MHY1, while only 30.2% (w/w) lipid based on cell dry weight was obtained from the reference strain. RNA-seq was then performed to analyze transcriptional changes during lipid biosynthesis after MHY1 gene inactivation. The expression of 1597 genes, accounting for 24.7% of annotated Y. lipolytica genes, changed significantly in the disruptant M-MHY1 during lipid biosynthesis. Differential gene expression analysis indicated that Mhy1p performs multiple functions and participates in a wide variety of biological processes, including lipid, amino acid and nitrogen metabolism. Notably, data analysis revealed increased carbon flux through lipid biosynthesis following MHY1 gene inactivation, accompanied by decreased carbon flux through amino acid biosynthesis. Moreover, Mhy1p regulates the cell cycle, and the cell cycle rate was enhanced in the disruptant M-MHY1. These results suggest that Mhy1p plays critical regulatory roles in diverse aspects of various biological processes, especially in lipid biosynthesis, amino acid and nitrogen metabolism and cell cycle. Our dataset appears to elucidate the crucial role of Mhy1p in lipid biosynthesis and serves as a resource for exploring physiological dimorphic growth in Y. lipolytica.
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Affiliation(s)
- Guangyuan Wang
- College of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao 266109, China
| | - Delong Li
- College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, Shandong 266109, China
| | - Zhengang Miao
- College of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao 266109, China
| | - Shanshan Zhang
- College of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao 266109, China
| | - Wenxing Liang
- College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, Shandong 266109, China
| | - Lin Liu
- College of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao 266109, China.
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Jiang Y, Xiao P, Shao Q, Qin H, Hu Z, Lei A, Wang J. Metabolic responses to ethanol and butanol in Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:239. [PMID: 29075323 PMCID: PMC5646117 DOI: 10.1186/s13068-017-0931-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 10/12/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Microalgae have been demonstrated to be among the most promising phototrophic species for producing renewable biofuels and chemicals. Ethanol and butanol are clean energy sources with good chemical and physical properties as alternatives to gasoline. However, biosynthesis of these two biofuels has not been achieved due to low tolerance of algal cells to ethanol or butanol. RESULTS With an eye to circumventing these problems in the future and engineering the robust alcohol-producing microalgal hosts, we investigated the metabolic responses of the model green alga Chlamydomonas reinhardtii to ethanol and butanol. Using a quantitative proteomics approach with iTRAQ-LC-MS/MS technologies, we detected the levels of 3077 proteins; 827 and 730 of which were differentially regulated by ethanol and butanol, respectively, at three time points. In particular, 41 and 59 proteins were consistently regulated during at least two sampling times. Multiple metabolic processes were affected by ethanol or butanol, and various stress-related proteins, transporters, cytoskeletal proteins, and regulators were induced as the major protection mechanisms against toxicity of the organic solvents. The most highly upregulated butanol response protein was Cre.770 peroxidase. CONCLUSIONS The study is the first comprehensive view of the metabolic mechanisms employed by C. reinhardtii to defend against ethanol or butanol toxicity. Moreover, the proteomic analysis provides a resource for investigating potential gene targets for engineering microalgae to achieve efficient biofuel production.
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Affiliation(s)
- Yongguang Jiang
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Peng Xiao
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Qing Shao
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Huan Qin
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Zhangli Hu
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Anping Lei
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Jiangxin Wang
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060 People’s Republic of China
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060 People’s Republic of China
- Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Shenzhen, 518060 People’s Republic of China
- Nanshan District Key Lab for Biopolymers and Safety Evaluation, Shenzhen University, Shenzhen, 518060 People’s Republic of China
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Imamura S, Taki K, Tanaka K. Construction of a rapamycin-susceptible strain of the unicellular red alga Cyanidioschyzon merolae for analysis of the target of rapamycin (TOR) function. J GEN APPL MICROBIOL 2017; 63:305-309. [PMID: 28954966 DOI: 10.2323/jgam.2017.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Keiko Taki
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
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46
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Prioretti L, Avilan L, Carrière F, Montané MH, Field B, Grégori G, Menand B, Gontero B. The inhibition of TOR in the model diatom Phaeodactylum tricornutum promotes a get-fat growth regime. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.08.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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47
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The TOR Signaling Network in the Model Unicellular Green Alga Chlamydomonas reinhardtii. Biomolecules 2017; 7:biom7030054. [PMID: 28704927 PMCID: PMC5618235 DOI: 10.3390/biom7030054] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 12/18/2022] Open
Abstract
Cell growth is tightly coupled to nutrient availability. The target of rapamycin (TOR) kinase transmits nutritional and environmental cues to the cellular growth machinery. TOR functions in two distinct multiprotein complexes, termed TOR complex 1 (TORC1) and TOR complex 2 (TORC2). While the structure and functions of TORC1 are highly conserved in all eukaryotes, including algae and plants, TORC2 core proteins seem to be missing in photosynthetic organisms. TORC1 controls cell growth by promoting anabolic processes, including protein synthesis and ribosome biogenesis, and inhibiting catabolic processes such as autophagy. Recent studies identified rapamycin-sensitive TORC1 signaling regulating cell growth, autophagy, lipid metabolism, and central metabolic pathways in the model unicellular green alga Chlamydomonas reinhardtii. The central role that microalgae play in global biomass production, together with the high biotechnological potential of these organisms in biofuel production, has drawn attention to the study of proteins that regulate cell growth such as the TOR kinase. In this review we discuss the recent progress on TOR signaling in algae.
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48
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Tan KWM, Lee YK. The dilemma for lipid productivity in green microalgae: importance of substrate provision in improving oil yield without sacrificing growth. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:255. [PMID: 27895709 PMCID: PMC5120525 DOI: 10.1186/s13068-016-0671-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/16/2016] [Indexed: 05/02/2023]
Abstract
Rising oil prices and concerns over climate change have resulted in more emphasis on research into renewable biofuels from microalgae. Unlike plants, green microalgae have higher biomass productivity, will not compete with food and agriculture, and do not require fertile land for cultivation. However, microalgae biofuels currently suffer from high capital and operating costs due to low yields and costly extraction methods. Microalgae grown under optimal conditions produce large amounts of biomass but with low neutral lipid content, while microalgae grown in nutrient starvation accumulate high levels of neutral lipids but are slow growing. Producing lipids while maintaining high growth rates is vital for biofuel production because high biomass productivity increases yield per harvest volume while high lipid content decreases the cost of extraction per unit product. Therefore, there is a need for metabolic engineering of microalgae to constitutively produce high amounts of lipids without sacrificing growth. Substrate availability is a rate-limiting step in balancing growth and fatty acid (FA) production because both biomass and FA synthesis pathways compete for the same substrates, namely acetyl-CoA and NADPH. In this review, we discuss the efforts made for improving biofuel production in plants and microorganisms, the challenges faced in achieving lipid productivity, and the important role of precursor supply for FA synthesis. The main focus is placed on the enzymes which catalyzed the reactions supplying acetyl-CoA and NADPH.
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Affiliation(s)
- Kenneth Wei Min Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545 Singapore
| | - Yuan Kun Lee
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545 Singapore
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Dobrenel T, Caldana C, Hanson J, Robaglia C, Vincentz M, Veit B, Meyer C. TOR Signaling and Nutrient Sensing. ANNUAL REVIEW OF PLANT BIOLOGY 2016; 67:261-85. [PMID: 26905651 DOI: 10.1146/annurev-arplant-043014-114648] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
All living organisms rely on nutrients to sustain cell metabolism and energy production, which in turn need to be adjusted based on available resources. The evolutionarily conserved target of rapamycin (TOR) protein kinase is a central regulatory hub that connects environmental information about the quantity and quality of nutrients to developmental and metabolic processes in order to maintain cellular homeostasis. TOR is activated by both nitrogen and carbon metabolites and promotes energy-consuming processes such as cell division, mRNA translation, and anabolism in times of abundance while repressing nutrient remobilization through autophagy. In animals and yeasts, TOR acts antagonistically to the starvation-induced AMP-activated kinase (AMPK)/sucrose nonfermenting 1 (Snf1) kinase, called Snf1-related kinase 1 (SnRK1) in plants. This review summarizes the immense knowledge on the relationship between TOR signaling and nutrients in nonphotosynthetic organisms and presents recent findings in plants that illuminate the crucial role of this pathway in conveying nutrient-derived signals and regulating many aspects of metabolism and growth.
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Affiliation(s)
- Thomas Dobrenel
- Institut Jean-Pierre Bourgin, UMR 1318 INRA AgroParisTech, ERL CNRS 3559, Saclay Plant Sciences, Versailles 78026, France;
- Umeå Plant Science Center, Department of Plant Physiology, Umeå University, Umeå 90187, Sweden
| | - Camila Caldana
- Molecular Physiology of Plant Biomass Production Group, Max Planck Partner Group, Brazilian Bioethanol Science and Technology Laboratory, CEP 13083-100 Campinas, São Paulo, Brazil
| | - Johannes Hanson
- Umeå Plant Science Center, Department of Plant Physiology, Umeå University, Umeå 90187, Sweden
| | - Christophe Robaglia
- Laboratoire de Génétique et Biophysique des Plantes, UMR 7265, DSV, IBEB, SBVME, CEA, CNRS, Aix Marseille Université, Faculté des Sciences de Luminy, Marseille 13009, France
| | - Michel Vincentz
- Laboratório de Genética de Plantas, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, CEP 13083-875 Campinas, São Paulo, Brazil
| | - Bruce Veit
- Forage Improvement, AgResearch, Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Christian Meyer
- Institut Jean-Pierre Bourgin, UMR 1318 INRA AgroParisTech, ERL CNRS 3559, Saclay Plant Sciences, Versailles 78026, France;
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Sun L, Yu Y, Hu W, Min Q, Kang H, Li Y, Hong Y, Wang X, Hong Y. Ribosomal protein S6 kinase1 coordinates with TOR-Raptor2 to regulate thylakoid membrane biosynthesis in rice. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:639-49. [PMID: 27102613 DOI: 10.1016/j.bbalip.2016.04.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 03/16/2016] [Accepted: 04/15/2016] [Indexed: 01/01/2023]
Abstract
Ribosomal protein S6 kinase (S6K) functions as a key component in the target of rapamycin (TOR) pathway involved in multiple processes in eukaryotes. The role and regulation of TOR-S6K in lipid metabolism remained unknown in plants. Here we provide genetic and pharmacological evidence that TOR-Raptor2-S6K1 is important for thylakoid galactolipid biosynthesis and thylakoid grana modeling in rice (Oryza sativa L.). Genetic suppression of S6K1 caused pale yellow-green leaves, defective thylakoid grana architecture. S6K1 directly interacts with Raptor2, a core component in TOR signaling, and S6K1 activity is regulated by Raptor2 and TOR. Plants with suppressed Raptor2 expression or reduced TOR activity by inhibitors mimicked the S6K1-deficient phenotype. A significant reduction in galactolipid content was found in the s6k1, raptor2 mutant or TOR-inhibited plants, which was accompanied by decreased transcript levels of the set of genes such as lipid phosphate phosphatase α5 (LPPα5), MGDG synthase 1 (MGD1), and DGDG synthase 1 (DGD1) involved in galactolipid synthesis, compared to the control plants. Moreover, loss of LPPα5 exhibited a similar phenotype with pale yellow-green leaves. These results suggest that TOR-Raptor2-S6K1 is important for modulating thylakoid membrane lipid biosynthesis, homeostasis, thus enhancing thylakoid grana architecture and normal photosynthesis ability in rice.
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Affiliation(s)
- Linxiao Sun
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yonghua Yu
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Weiqin Hu
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiming Min
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Huiling Kang
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yilu Li
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yue Hong
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xuemin Wang
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yueyun Hong
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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