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Li A, Yan Y, Qiu J, Yan G, Zhao P, Li M, Ji Y, Wang G, Meng F, Li Y, Metcalf JS, Banack SA. Putative biosynthesis mechanism of the neurotoxin β-N-methylamino-L-alanine in marine diatoms based on a transcriptomics approach. JOURNAL OF HAZARDOUS MATERIALS 2023; 441:129953. [PMID: 36116313 DOI: 10.1016/j.jhazmat.2022.129953] [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: 07/06/2022] [Revised: 08/29/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
The neurotoxin β-N-methylamino-L-alanine (BMAA) has been presumed as an environmental cause of human neurodegenerative disorders, such as Alzheimer's disease. Marine diatoms Thalassiosira minima are demonstrated here to produce BMAA-containing proteins in axenic culture while the isomer diaminobutyric acid was bacterially produced. In the co-culture with Cyanobacterium aponinum, diatom growth was inhibited but the biosynthesis of BMAA-containing proteins was stimulated up to seven times higher than that of the control group by cell-cell interactions. The stimulation effect was not caused by the cyanobacterial filtrate. Nitrogen deprivation also doubled the BMAA content of T. minima cells. Transcriptome analysis of the diatom in mixed culture revealed that pathways involved in T. minima metabolism and cellular functions were mainly influenced, including KEGG pathways valine and leucine/isoleucine degradation, endocytosis, pantothenate and CoA biosynthesis, and SNARE interactions in vesicular transport. Based on the expression changes of genes related to protein biosynthesis, it was hypothesized that ubiquitination and autophagy suppression, and limited COPII vesicles transport accuracy and efficiency were responsible for biosynthesis of BMAA-containing proteins in T. minima. This study represents a first application of transcriptomics to investigate the biological processes associated with BMAA biosynthesis in diatoms.
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Affiliation(s)
- Aifeng Li
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China.
| | - Yeju Yan
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Jiangbing Qiu
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Guowang Yan
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Peng Zhao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Min Li
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Ying Ji
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Guixiang Wang
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Fanping Meng
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Yang Li
- Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, College of Life Science, South China Normal University, West 55 of Zhongshan Avenue, Guangzhou 510631, China
| | - James S Metcalf
- Brain Chemistry Labs, Institute for Ethnomedicine, PO Box 3464, Jackson, WY 83001, USA
| | - Sandra A Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, PO Box 3464, Jackson, WY 83001, USA
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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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Phaeodactylum tricornutum as a potential feedstock for an integrated biorefinery process under varying cultivation conditions. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2022.102508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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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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Slocombe SP, Huete-Ortega M, Kapoore RV, Okurowska K, Mair A, Day JG, Stanley MS, Vaidyanathan S. Enabling large-scale production of algal oil in continuous output mode. iScience 2021; 24:102743. [PMID: 34278255 PMCID: PMC8264157 DOI: 10.1016/j.isci.2021.102743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/07/2021] [Accepted: 06/14/2021] [Indexed: 11/08/2022] Open
Abstract
Large-scale algal oil production requires continuous outputs and a trade-off between growth and oil content. Two unrelated marine algae (Nannochloropsis oceanica [CCAP 849/10] and Chlorella vulgaris [CCAP 211/21A]) that showed high oil production under batch culture were studied under controlled semicontinuous cultivation conditions. Three essential attributes maximized oil productivity: (i) downregulation of cell size to maximize light absorption under N limitation; (ii) low nutrient-depletion thresholds to trigger oil induction; (iii) a means of carbohydrate suppression in favor of oil. N. oceanica responded better to input N/P variations and is more suited to continuous oil production. A low N/P ratio was effective in both suppressing carbohydrate and reducing cell size concomitant with oil production. In C. vulgaris, nutrient starvation thresholds for oil were higher and carbohydrate was preferentially induced, which impeded stress-level optimization for oil. These differences, which impact continuous oil production at scale, are driven by species adaptation to specific marine habitats. VIDEO ABSTRACT VIDEO ABSTRACT
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Affiliation(s)
- Stephen P. Slocombe
- The Scottish Association for Marine Science (SAMS), Scottish Marine Institute, Oban, Argyll PA37 1QA, UK
| | - Maria Huete-Ortega
- Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, ChELSI Institute, The University of Sheffield, Sheffield S1 3JD, UK
| | - Rahul Vijay Kapoore
- Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, ChELSI Institute, The University of Sheffield, Sheffield S1 3JD, UK
| | - Katarzyna Okurowska
- Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, ChELSI Institute, The University of Sheffield, Sheffield S1 3JD, UK
| | - Alison Mair
- The Scottish Association for Marine Science (SAMS), Scottish Marine Institute, Oban, Argyll PA37 1QA, UK
| | - John G. Day
- The Scottish Association for Marine Science (SAMS), Scottish Marine Institute, Oban, Argyll PA37 1QA, UK
| | - Michele S. Stanley
- The Scottish Association for Marine Science (SAMS), Scottish Marine Institute, Oban, Argyll PA37 1QA, UK
| | - Seetharaman Vaidyanathan
- Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, ChELSI Institute, The University of Sheffield, Sheffield S1 3JD, UK
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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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Avilan L, Lebrun R, Puppo C, Citerne S, Cuiné S, Li‐Beisson Y, Menand B, Field B, Gontero B. ppGpp influences protein protection, growth and photosynthesis in Phaeodactylum tricornutum. THE NEW PHYTOLOGIST 2021; 230:1517-1532. [PMID: 33595847 PMCID: PMC8252717 DOI: 10.1111/nph.17286] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/08/2021] [Indexed: 05/08/2023]
Abstract
Chloroplasts retain elements of a bacterial stress response pathway that is mediated by the signalling nucleotides guanosine penta- and tetraphosphate ((p)ppGpp). In the model flowering plant Arabidopsis, ppGpp acts as a potent regulator of plastid gene expression and influences photosynthesis, plant growth and development. However, little is known about ppGpp metabolism or its evolution in other photosynthetic eukaryotes. Here, we studied the function of ppGpp in the diatom Phaeodactylum tricornutum using transgenic lines containing an inducible system for ppGpp accumulation. We used these lines to investigate the effects of ppGpp on growth, photosynthesis, lipid metabolism and protein expression. We demonstrate that ppGpp accumulation reduces photosynthetic capacity and promotes a quiescent-like state with reduced proliferation and ageing. Strikingly, using nontargeted proteomics, we discovered that ppGpp accumulation also leads to the coordinated upregulation of a protein protection response in multiple cellular compartments. Our findings highlight the importance of ppGpp as a fundamental regulator of chloroplast function across different domains of life, and lead to new questions about the molecular mechanisms and roles of (p)ppGpp signalling in photosynthetic eukaryotes.
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Affiliation(s)
- Luisana Avilan
- CNRSBIPUMR 7281IMM FR 3479Aix Marseille Univ31 Chemin Joseph AiguierMarseille13009France
- Centre for Enzyme InnovationSchool of Biological SciencesInstitute of Biological and Biomedical SciencesUniversity of PortsmouthPortsmouthPO1 2DYUK
| | - Regine Lebrun
- Plate‐forme ProtéomiqueMarseille Protéomique (MaP)IMM FR 3479, 31 Chemin Joseph AiguierMarseille13009France
| | - Carine Puppo
- CNRSBIPUMR 7281IMM FR 3479Aix Marseille Univ31 Chemin Joseph AiguierMarseille13009France
| | - Sylvie Citerne
- Institut Jean‐Pierre BourginINRAEAgroParisTechUniversité Paris‐SaclayVersailles78000France
| | - Stephane Cuiné
- CEA, CNRS, UMR7265 BIAMCEA CadaracheAix‐Marseille UnivSaint‐Paul‐lez Durance13108France
| | - Yonghua Li‐Beisson
- CEA, CNRS, UMR7265 BIAMCEA CadaracheAix‐Marseille UnivSaint‐Paul‐lez Durance13108France
| | - Benoît Menand
- CEA, CNRS, UMR7265 BIAMAix‐Marseille UnivMarseille13009France
| | - Ben Field
- CEA, CNRS, UMR7265 BIAMAix‐Marseille UnivMarseille13009France
| | - Brigitte Gontero
- CNRSBIPUMR 7281IMM FR 3479Aix Marseille Univ31 Chemin Joseph AiguierMarseille13009France
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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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