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Solovchenko A, Plouviez M, Khozin-Goldberg I. Getting Grip on Phosphorus: Potential of Microalgae as a Vehicle for Sustainable Usage of This Macronutrient. PLANTS (BASEL, SWITZERLAND) 2024; 13:1834. [PMID: 38999674 PMCID: PMC11243885 DOI: 10.3390/plants13131834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Revised: 06/24/2024] [Accepted: 07/01/2024] [Indexed: 07/14/2024]
Abstract
Phosphorus (P) is an important and irreplaceable macronutrient. It is central to energy and information storage and exchange in living cells. P is an element with a "broken geochemical cycle" since it lacks abundant volatile compounds capable of closing the P cycle. P fertilizers are critical for global food security, but the reserves of minable P are scarce and non-evenly distributed between countries of the world. Accordingly, the risks of global crisis due to limited access to P reserves are expected to be graver than those entailed by competition for fossil hydrocarbons. Paradoxically, despite the scarcity and value of P reserves, its usage is extremely inefficient: the current waste rate reaches 80% giving rise to a plethora of unwanted consequences such as eutrophication leading to harmful algal blooms. Microalgal biotechnology is a promising solution to tackle this challenge. The proposed review briefly presents the relevant aspects of microalgal P metabolism such as cell P reserve composition and turnover, and the regulation of P uptake kinetics for maximization of P uptake efficiency with a focus on novel knowledge. The multifaceted role of polyPhosphates, the largest cell depot for P, is discussed with emphasis on the P toxicity mediated by short-chain polyPhosphates. Opportunities and hurdles of P bioremoval via P uptake from waste streams with microalgal cultures, either suspended or immobilized, are discussed. Possible avenues of P-rich microalgal biomass such as biofertilizer production or extraction of valuable polyPhosphates and other bioproducts are considered. The review concludes with a comprehensive assessment of the current potential of microalgal biotechnology for ensuring the sustainable usage of phosphorus.
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Affiliation(s)
- Alexei Solovchenko
- Department of Bioengineering, Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234 Moscow, Russia
| | | | - Inna Khozin-Goldberg
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion University of the Negev, Sde-Boqer Campus, Midreshet Ben-Gurion 8499000, Israel
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2
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Prazyan A, Podlutskii M, Volkova P, Kazakova E, Bitarishvili S, Shesterikova E, Saburov V, Makarenko E, Lychenkova M, Korol M, Kazakov E, Moiseev A, Geras’kin S, Bondarenko E. Comparative Analysis of the Effect of Gamma-, Electron, and Proton Irradiation on Transcriptomic Profile of Hordeum vulgare L. Seedlings: In Search for Molecular Contributors to Abiotic Stress Resilience. PLANTS (BASEL, SWITZERLAND) 2024; 13:342. [PMID: 38337875 PMCID: PMC10857502 DOI: 10.3390/plants13030342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/19/2024] [Accepted: 01/20/2024] [Indexed: 02/12/2024]
Abstract
The development of adaptation strategies for crops under ever-changing climate conditions is a critically important food security issue. Studies of barley responses to ionising radiation showed that this evolutionarily ancient stress factor can be successfully used to identify molecular pathways involved in adaptation to a range of abiotic stressors. In order to identify potential molecular contributors to abiotic stress resilience, we examined the transcriptomic profiles of barley seedlings after exposure to γ-rays, electrons, and protons. A total of 553 unique differentially expressed genes with increased expression and 124 with decreased expression were detected. Among all types of radiation, the highest number of differentially expressed genes was observed in electron-irradiated samples (428 upregulated and 56 downregulated genes). Significant upregulation after exposure to the three types of radiation was shown by a set of ROS-responsive genes, genes involved in DNA repair, cell wall metabolism, auxin biosynthesis and signalling, as well as photosynthesis-related genes. Most of these genes are known to be involved in plant ROS-mediated responses to other abiotic stressors, especially with genotoxic components, such as heavy metals and drought. Ultimately, the modulation of molecular pathways of plant responses to ionising radiation may be a prospective tool for stress tolerance programmes.
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Affiliation(s)
- Alexander Prazyan
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
| | - Mikhail Podlutskii
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
| | | | - Elizaveta Kazakova
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
| | - Sofia Bitarishvili
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
| | - Ekaterina Shesterikova
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
| | - Vyacheslav Saburov
- A. Tsyb Medical Radiological Research Centre—Branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, 249036 Obninsk, Russia
| | - Ekaterina Makarenko
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
| | - Maria Lychenkova
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
| | - Marina Korol
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
| | - Evgeniy Kazakov
- A. Tsyb Medical Radiological Research Centre—Branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, 249036 Obninsk, Russia
| | - Alexander Moiseev
- A. Tsyb Medical Radiological Research Centre—Branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, 249036 Obninsk, Russia
| | - Stanislav Geras’kin
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
| | - Ekaterina Bondarenko
- Russian Institute of Radiology and Agroecology of National Research Centre “Kurchatov Institute”, 249035 Obninsk, Russia
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3
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Tissot S, Guimard L, Meliani J, Boutry J, Dujon AM, Capp JP, Tökölyi J, Biro PA, Beckmann C, Fontenille L, Do Khoa N, Hamede R, Roche B, Ujvari B, Nedelcu AM, Thomas F. The impact of food availability on tumorigenesis is evolutionarily conserved. Sci Rep 2023; 13:19825. [PMID: 37963956 PMCID: PMC10645767 DOI: 10.1038/s41598-023-46896-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 11/07/2023] [Indexed: 11/16/2023] Open
Abstract
The inability to control cell proliferation results in the formation of tumors in many multicellular lineages. Nonetheless, little is known about the extent of conservation of the biological traits and ecological factors that promote or inhibit tumorigenesis across the metazoan tree. Particularly, changes in food availability have been linked to increased cancer incidence in humans, as an outcome of evolutionary mismatch. Here, we apply evolutionary oncology principles to test whether food availability, regardless of the multicellular lineage considered, has an impact on tumorigenesis. We used two phylogenetically unrelated model systems, the cnidarian Hydra oligactis and the fish Danio rerio, to investigate the impact of resource availability on tumor occurrence and progression. Individuals from healthy and tumor-prone lines were placed on four diets that differed in feeding frequency and quantity. For both models, frequent overfeeding favored tumor emergence, while lean diets appeared more protective. In terms of tumor progression, high food availability promoted it, whereas low resources controlled it, but without having a curative effect. We discuss our results in light of current ideas about the possible conservation of basic processes governing cancer in metazoans (including ancestral life history trade-offs at the cell level) and in the framework of evolutionary medicine.
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Affiliation(s)
- Sophie Tissot
- CREEC/MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France.
| | - Lena Guimard
- CREEC/MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France
| | - Jordan Meliani
- CREEC/MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France
| | - Justine Boutry
- CREEC/MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France
| | - Antoine M Dujon
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, VIC, Australia
| | - Jean-Pascal Capp
- Toulouse Biotechnology Institute, University of Toulouse, INSA, CNRS, INRAE, Toulouse, France
| | - Jácint Tökölyi
- MTA-DE "Momentum" Ecology, Evolution and Developmental Biology Research Group, Department of Evolutionary Zoology, University of Debrecen, Debrecen, 4032, Hungary
| | - Peter A Biro
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, VIC, Australia
| | - Christa Beckmann
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, VIC, Australia
- School of Science, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Richmond, NSW, 2753, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Laura Fontenille
- AZELEAD, 377 Rue du Professeur Blayac, 34080, Montpellier, France
| | - Nam Do Khoa
- AZELEAD, 377 Rue du Professeur Blayac, 34080, Montpellier, France
| | - Rodrigo Hamede
- School of Natural Sciences, University of Tasmania, Hobart, TAS, Australia
| | - Benjamin Roche
- CREEC/MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France
- Departamento de Etología, Fauna Silvestre y Animales de Laboratorio, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Beata Ujvari
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, VIC, Australia
| | - Aurora M Nedelcu
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada
| | - Frédéric Thomas
- CREEC/MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France
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4
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Wang L, Jia X, Xu L, Yu J, Ren S, Yang Y, Wang K, López-Arredondo D, Herrera-Estrella L, Lambers H, Yi K. Engineering microalgae for water phosphorus recovery to close the phosphorus cycle. PLANT BIOTECHNOLOGY JOURNAL 2023. [PMID: 36920783 DOI: 10.1111/pbi.14040] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
As a finite and non-renewable resource, phosphorus (P) is essential to all life and crucial for crop growth and food production. The boosted agricultural use and associated loss of P to the aquatic environment are increasing environmental pollution, harming ecosystems, and threatening future global food security. Thus, recovering and reusing P from water bodies is urgently needed to close the P cycle. As a natural, eco-friendly, and sustainable reclamation strategy, microalgae-based biological P recovery is considered a promising solution. However, the low P-accumulation capacity and P-removal efficiency of algal bioreactors restrict its application. Herein, it is demonstrated that manipulating genes involved in cellular P accumulation and signalling could triple the Chlamydomonas P-storage capacity to ~7% of dry biomass, which is the highest P concentration in plants to date. Furthermore, the engineered algae could recover P from wastewater almost three times faster than the unengineered one, which could be directly used as a P fertilizer. Thus, engineering genes involved in cellular P accumulation and signalling in microalgae could be a promising strategy to enhance P uptake and accumulation, which have the potential to accelerate the application of algae for P recovery from the water body and closing the P cycle.
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Affiliation(s)
- Long Wang
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xianqing Jia
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lei Xu
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiahong Yu
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Suna Ren
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yujie Yang
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | | | - Damar López-Arredondo
- Department of Plant and Soil Science, Institute of Genomics for Crop Abiotic Stress Tolerance, Texas Tech University, Lubbock, TX, USA
| | - Luis Herrera-Estrella
- Department of Plant and Soil Science, Institute of Genomics for Crop Abiotic Stress Tolerance, Texas Tech University, Lubbock, TX, USA
- Laboratorio Nacional de Genómica para la Biodiversidad (UGA), Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Guanajuato, Mexico
| | - Hans Lambers
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
| | - Keke Yi
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
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5
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Salarvan F, Meydan H, Aksoy M. Transcription level and phylogeny analyses of Chlamydomonas reinhardtii arylsulfatases. J Eukaryot Microbiol 2023; 70:e12943. [PMID: 36018447 DOI: 10.1111/jeu.12943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/24/2022] [Accepted: 08/24/2022] [Indexed: 01/13/2023]
Abstract
Sulfur is a required macroelement for all organisms, and sulfate deficiency causes growth and developmental defects. Arylsulfatases (ARS) hydrolyze sulfate from sulfate esters and make sulfate bioavailable for plant uptake. These enzymes are found in microorganisms and animals; however, plant genomes do not encode any ARS gene. Our database searches found nineteen ARS genes in the genome of Chlamydomonas reinhardtii. Among these, ARS1 and ARS2 were studied in the literature; however, the remaining seventeen gene models were not studied. Our results show that putative polypeptide sequences of the ARS gene models all have the sulfatase domain and sulfatase motifs found in known ARSs. Phylogenetic analyses show that C. reinhardtii proteins are in close branches with Volvox carterii proteins while they were clustered in a separate group from Homo sapiens and bacterial species (Pseudomonas aeruginosa and Rhodopirellula baltica SH1), except human Sulf1, Sulf2, and GNS are clustered with algal ARSs. RT-PCR analyses showed that transcription of ARS6, ARS7, ARS11, ARS12, ARS13, ARS17, and ARS19 increased under sulfate deficiency. However, this increase was not as high as the increase seen in ARS2. Since plant genomes do not encode any ARS gene, our results highlight the importance of microbial ARS genes.
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Affiliation(s)
- Fatma Salarvan
- Department of Agricultural Biotechnology, Faculty of Agriculture, Akdeniz University, Antalya, Türkiye
| | - Hasan Meydan
- Department of Agricultural Biotechnology, Faculty of Agriculture, Akdeniz University, Antalya, Türkiye
| | - Münevver Aksoy
- Department of Agricultural Biotechnology, Faculty of Agriculture, Akdeniz University, Antalya, Türkiye
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6
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Saggere RMS, Lee CWJ, Chan ICW, Durnford DG, Nedelcu AM. A life-history trade-off gene with antagonistic pleiotropic effects on reproduction and survival in limiting environments. Proc Biol Sci 2022; 289:20212669. [PMID: 35078364 PMCID: PMC8790358 DOI: 10.1098/rspb.2021.2669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Although life-history trade-offs are central to life-history evolution, their mechanistic basis is often unclear. Traditionally, trade-offs are understood in terms of competition for limited resources among traits within an organism, which could be mediated by signal transduction pathways at the level of cellular metabolism. Nevertheless, trade-offs are also thought to be produced as a consequence of the performance of one activity generating negative consequences for other traits, or the result of genes or pathways that simultaneously regulate two life-history traits in opposite directions (antagonistic pleiotropy), independent of resource allocation. Yet examples of genes with antagonistic effects on life-history traits are limited. This study provides direct evidence for a gene-RLS1, that is involved in increasing survival in nutrient-limiting environments at a cost to immediate reproduction in the single-celled photosynthetic alga, Chlamydomonas reinhardtii. Specifically, we show that RLS1 mutants are unable to properly suppress their reproduction in phosphate-deprived conditions. Although these mutants have an immediate reproductive advantage relative to the parental strain, their long-term survival is negatively affected. Our data suggest that RLS1 is a bona fide life-history trade-off gene that suppresses immediate reproduction and ensures survival by downregulating photosynthesis in limiting environments, as part of the general acclimation response to nutrient deprivation in photosynthetic organisms.
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Affiliation(s)
- Rani M. S. Saggere
- Biology Department, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, Canada E3B 5A3
| | - Christopher W. J. Lee
- Biology Department, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, Canada E3B 5A3
| | - Irina C. W. Chan
- Biology Department, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, Canada E3B 5A3
| | - Dion G. Durnford
- Biology Department, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, Canada E3B 5A3
| | - Aurora M. Nedelcu
- Biology Department, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, Canada E3B 5A3
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7
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Grinko A, Alqoubaili R, Lapina T, Ermilova E. Truncated hemoglobin 2 modulates phosphorus deficiency response by controlling of gene expression in nitric oxide-dependent pathway in Chlamydomonas reinhardtii. PLANTA 2021; 254:39. [PMID: 34319485 DOI: 10.1007/s00425-021-03691-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Truncated hemoglobin 2 is involved in fine-tuning of PSR1-regulated gene expression during phosphorus deprivation. Truncated hemoglobins form a large family found in all domains of life. However, a majority of physiological functions of these proteins remain to be elucidated. In the model alga Chlamydomonas reinhardtii, macro-nutritional deprivation is known to elevate truncated hemoglobin 2 (THB2). This study investigated the role of THB2 in the regulation of a subset of phosphorus (P) limitation-responsive genes in cells suffering from P-deficiency. Underexpression of THB2 in amiTHB2 strains resulted in downregulation of a suite of P deprivation-induced genes encoding proteins with different subcellular location and functions (e.g., PHOX, LHCSR3.1, LHCSR3.2, PTB2, and PTB5). Moreover, our results provided primary evidence that the soluble guanylate cyclase 12 gene (CYG12) is a component of the P deprivation regulation. Furthermore, the transcription of PSR1 gene for the most critical regulator in the acclimation process under P restriction was repressed by nitric oxide (NO). Collectively, the results indicated a tight regulatory link between the THB2-controlled NO levels and PSR1-dependent induction of several P deprivation responsive genes with various roles in cells during P-limitation.
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Affiliation(s)
- Alexandra Grinko
- Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, 199034, Russia
| | - Reem Alqoubaili
- Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, 199034, Russia
| | - Tatiana Lapina
- Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, 199034, Russia
| | - Elena Ermilova
- Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, 199034, Russia.
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8
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The evolution of multicellularity and cancer: views and paradigms. Biochem Soc Trans 2021; 48:1505-1518. [PMID: 32677677 DOI: 10.1042/bst20190992] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 12/16/2022]
Abstract
Conceptually and mechanistically, the evolution of multicellularity required the integration of single cells into new functionally, reproductively and evolutionary stable multicellular individuals. As part of this process, a change in levels of selection occurred, with selection at the multicellular level overriding selection at the cell level. The stability of multicellular individuals is dependent on a combination of mechanisms that supress within-group evolution, by both reducing the occurrence of somatic mutations as well as supressing somatic selection. Nevertheless, mutations that, in a particular microenvironment, confer mutant lineages a fitness advantage relative to normal somatic cells do occur, and can result in cancer. This minireview highlights several views and paradigms that relate the evolution of multicellularity to cancer. As a phenomenon, cancer is generally understood as a failure of multicellular systems to suppress somatic evolution. However, as a disease, cancer is interpreted in different frameworks: (i) a breakdown of cooperative behaviors underlying the evolution of multicellularity, (ii) a disruption of molecular networks established during the emergence of multicellularity to impose constraints on single-celled units, or (iii) an atavistic state resulting from reactivating primitive programs that originated in the earliest unicellular species. A number of assumptions are common in all the views relating cancer as a disease to the evolution of multicellularity. For instance, cancer is considered a reversal to unicellularity, and cancer cells are thought to both resemble unicellular organisms and benefit from ancestral-like traits. Nevertheless, potential limitations of current paradigms should be acknowledged as different perspectives can provide novel insights with potential therapeutic implications.
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9
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Plouviez M, Fernández E, Grossman AR, Sanz-Luque E, Sells M, Wheeler D, Guieysse B. Responses of Chlamydomonas reinhardtii during the transition from P-deficient to P-sufficient growth (the P-overplus response): The roles of the vacuolar transport chaperones and polyphosphate synthesis. JOURNAL OF PHYCOLOGY 2021; 57:988-1003. [PMID: 33778959 DOI: 10.1111/jpy.13145] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 01/10/2021] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Phosphorus (P) assimilation and polyphosphate (polyP) synthesis were investigated in Chlamydomonas reinhardtii by supplying phosphate (PO43- ; 10 mg P·L-1 ) to P-depleted cultures of wildtypes, mutants with defects in genes involved in the vacuolar transporter chaperone (VTC) complex, and VTC-complemented strains. Wildtype C. reinhardtii assimilated PO43- and stored polyP within minutes of adding PO43- to cultures that were P-deprived, demonstrating that these cells were metabolically primed to assimilate and store PO43- . In contrast, vtc1 and vtc4 mutant lines assayed under the same conditions never accumulated polyP, and PO43- assimilation was considerably decreased in comparison with the wildtypes. In addition, to confirm the bioinformatics inferences and previous experimental work that the VTC complex of C. reinhardtii has a polyP polymerase function, these results evidence the influence of polyP synthesis on PO43- assimilation in C. reinhardtii. RNA-sequencing was carried out on C. reinhardtii cells that were either P-depleted (control) or supplied with PO43- following P depletion (treatment) in order to identify changes in the levels of mRNAs correlated with the P status of the cells. This analysis showed that the levels of VTC1 and VTC4 transcripts were strongly reduced at 5 and 24 h after the addition of PO43- to the cells, although polyP granules were continuously synthesized during this 24 h period. These results suggest that the VTC complex remains active for at least 24 h after supplying the cells with PO43- . Further bioassays and sequence analyses suggest that inositol phosphates may control polyP synthesis via binding to the VTC SPX domain.
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Affiliation(s)
- Maxence Plouviez
- School of Food and Advanced Technology, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - Emilio Fernández
- Department of Biochemistry and Molecular Biology, University of Cordoba, Cordoba, 14071, Spain
| | - Arthur Robert Grossman
- Department of Plant Biology, The Carnegie Institution for Science, 260 Panama Street, Stanford, California, 94305, USA
- Department of Biology, Stanford University, Stanford, California, 94305, USA
| | - Emanuel Sanz-Luque
- Department of Biochemistry and Molecular Biology, University of Cordoba, Cordoba, 14071, Spain
- Department of Plant Biology, The Carnegie Institution for Science, 260 Panama Street, Stanford, California, 94305, USA
| | - Matthew Sells
- School of Food and Advanced Technology, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - David Wheeler
- New South Wales Department of Primary Industries, 161 Kite St, Orange, New South Wales, 2800, Australia
| | - Benoit Guieysse
- School of Food and Advanced Technology, Massey University, Private Bag 11222, Palmerston North, New Zealand
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10
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Wang L, Xiao L, Yang H, Chen G, Zeng H, Zhao H, Zhu Y. Genome-Wide Identification, Expression Profiling, and Evolution of Phosphate Transporter Gene Family in Green Algae. Front Genet 2020; 11:590947. [PMID: 33133172 PMCID: PMC7578391 DOI: 10.3389/fgene.2020.590947] [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: 08/03/2020] [Accepted: 09/07/2020] [Indexed: 11/26/2022] Open
Abstract
Phosphorus (P) is an essential nutrient for plant growth and development. Phosphate transporters (PHTs) are trans-membrane proteins that mediate the uptake and translocation of phosphate (Pi) in green plants. The PHT family including PHT1, PHT2, PHT3 and PHT4 subfamilies are well-studied in land plants; however, PHT genes in green algae are poorly documented and not comprehensively identified. Here, we analyzed the PHTs in a model green alga Chlamydomonas reinhardtii and found 25 putative PHT genes, which can be divided into four subfamilies. The subfamilies of CrPTA, CrPTB, CrPHT3, and CrPHT4 contain four, eleven, one, and nine genes, respectively. The structure, chromosomal distribution, subcellular localization, duplication, phylogenies, and motifs of these genes were systematically analyzed in silico. Expression profile analysis showed that CrPHT genes displayed differential expression patterns under P starvation condition. The expression levels of CrPTA1 and CrPTA3 were down-regulated, while the expression of most CrPTB genes was up-regulated under P starvation, which may be controlled by CrPSR1. The transcript abundance of most CrPHT3 and CrPHT4 genes was not significantly affected by P starvation except CrPHT4-3, CrPHT4-4, and CrPHT4-6. Our results provided basic information for understanding the evolution and features of the PHT family in green algae.
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Affiliation(s)
- Long Wang
- Agricultural Resource and Environment Experiment Teaching Center, College of Resource and Environment Science, Nanjing Agricultural University, Nanjing, China.,Key Laboratory of Plant Nutrition and Fertilizers, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Liang Xiao
- Agricultural Resource and Environment Experiment Teaching Center, College of Resource and Environment Science, Nanjing Agricultural University, Nanjing, China
| | - Haiyan Yang
- Agricultural Resource and Environment Experiment Teaching Center, College of Resource and Environment Science, Nanjing Agricultural University, Nanjing, China
| | - Guanglei Chen
- Agricultural Resource and Environment Experiment Teaching Center, College of Resource and Environment Science, Nanjing Agricultural University, Nanjing, China
| | - Houqing Zeng
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Hongyu Zhao
- Key Laboratory of Plant Nutrition and Fertilizers, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yiyong Zhu
- Agricultural Resource and Environment Experiment Teaching Center, College of Resource and Environment Science, Nanjing Agricultural University, Nanjing, China
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11
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Filina V, Grinko A, Ermilova E. Truncated Hemoglobins 1 and 2 Are Implicated in the Modulation of Phosphorus Deficiency-Induced Nitric Oxide Levels in Chlamydomonas. Cells 2019; 8:cells8090947. [PMID: 31438612 PMCID: PMC6770159 DOI: 10.3390/cells8090947] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/16/2019] [Accepted: 08/19/2019] [Indexed: 12/16/2022] Open
Abstract
Truncated hemoglobins (trHbs) form a widely distributed family of proteins found in archaea, bacteria, and eukaryotes. Accumulating evidence suggests that trHbs may be implicated in functions other than oxygen delivery, but these roles are largely unknown. Characterization of the conditions that affect trHb expression and investigation of their regulatory mechanisms will provide a framework for elucidating the functions of these globins. Here, the transcription of Chlamydomonas trHb genes (THB1–12) under conditions of phosphorus (P) deprivation was analyzed. Three THB genes, THB1, THB2, and THB12 were expressed at the highest level. For the first time, we demonstrate the synthesis of nitric oxide (NO) under P-limiting conditions and the production of NO by cells via a nitrate reductase-independent pathway. To clarify the functions of THB1 and THB2, we generated and analyzed strains in which these THBs were strongly under-expressed by using an artificial microRNA approach. Similar to THB1 knockdown, the depletion of THB2 led to a decrease in cell size and chlorophyll levels. We provide evidence that the knockdown of THB1 or THB2 enhanced NO production under P deprivation. Overall, these results demonstrate that THB1 and THB2 are likely to contribute, at least in part, to acclimation responses in P-deprived Chlamydomonas.
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Affiliation(s)
- Valentina Filina
- Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia
| | - Alexandra Grinko
- Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia
| | - Elena Ermilova
- Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia.
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12
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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: 187] [Impact Index Per Article: 31.2] [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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13
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Charles ED, Muhamadali H, Goodacre R, Pittman JK. Biochemical signatures of acclimation by Chlamydomonas reinhardtii to different ionic stresses. ALGAL RES 2019. [DOI: 10.1016/j.algal.2018.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Couso I, Pérez-Pérez ME, Martínez-Force E, Kim HS, He Y, Umen JG, Crespo JL. Autophagic flux is required for the synthesis of triacylglycerols and ribosomal protein turnover in Chlamydomonas. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1355-1367. [PMID: 29053817 PMCID: PMC6018900 DOI: 10.1093/jxb/erx372] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 09/28/2017] [Indexed: 05/19/2023]
Abstract
Autophagy is an intracellular catabolic process that allows cells to recycle unneeded or damaged material to maintain cellular homeostasis. This highly dynamic process is characterized by the formation of double-membrane vesicles called autophagosomes, which engulf and deliver the cargo to the vacuole. Flow of material through the autophagy pathway and its degradation in the vacuole is known as autophagic flux, and reflects the autophagic degradation activity. A number of assays have been developed to determine autophagic flux in yeasts, mammals, and plants, but it has not been examined yet in algae. Here we analyzed autophagic flux in the model green alga Chlamydomonas reinhardtii. By monitoring specific autophagy markers such as ATG8 lipidation and using immunofluorescence and electron microscopy techniques, we show that concanamycin A, a vacuolar ATPase inhibitor, blocks autophagic flux in Chlamydomonas. Our results revealed that vacuolar lytic function is needed for the synthesis of triacylglycerols and the formation of lipid bodies in nitrogen- or phosphate-starved cells. Moreover, we found that concanamycin A treatment prevented the degradation of ribosomal proteins RPS6 and RPL37 under nitrogen or phosphate deprivation. These results indicate that autophagy might play an important role in the regulation of lipid metabolism and the recycling of ribosomal proteins under nutrient limitation in Chlamydomonas.
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Affiliation(s)
- Inmaculada Couso
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Seville, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Seville, Spain
| | - Enrique Martínez-Force
- Instituto de la Grasa (CSIC), Edificio 46, Campus Universitario Pablo de Olavide, Seville, Spain
| | - Hee-Sik Kim
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Yonghua He
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - James G Umen
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Seville, Spain
- Correspondence:
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15
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Janse van Rensburg HC, Van den Ende W. UDP-Glucose: A Potential Signaling Molecule in Plants? FRONTIERS IN PLANT SCIENCE 2017; 8:2230. [PMID: 29375604 PMCID: PMC5767297 DOI: 10.3389/fpls.2017.02230] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/19/2017] [Indexed: 05/07/2023]
Abstract
This perspective paper focuses on the most recent results suggesting a potential role for UDP-Glucose as a signaling molecule in plants. In animals, UDP-Glucose is well-established as an extracellular signaling molecule that is sensed by G-protein coupled receptors, activating several downstream defense mechanisms. Recent studies have shown that abnormal growth occurred in both vegetative and reproductive tissue of plants with reduced UDP-Glucose levels, and this could be rescued by exogenous UDP-Glucose. In plants with increased biomass accumulation, the genes involved in UDP-Glucose production were up-regulated. However, excessive endogenous accumulation of UDP-Glucose induced programmed cell death (PCD), and this could also be obtained by exogenous UDP-Glucose application. Plants with decreased UDP-glucose were insensitive to pathogen induced PCD. We speculate that UDP-Glucose acts as an extracellular signaling molecule in plants, and that it may be perceived as a damage-associated molecular pattern.
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16
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Warakanont J, Tsai CH, Michel EJS, Murphy GR, Hsueh PY, Roston RL, Sears BB, Benning C. Chloroplast lipid transfer processes in Chlamydomonas reinhardtii involving a TRIGALACTOSYLDIACYLGLYCEROL 2 (TGD2) orthologue. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 84:1005-20. [PMID: 26496373 DOI: 10.1111/tpj.13060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/05/2015] [Accepted: 10/16/2015] [Indexed: 05/10/2023]
Abstract
In plants, lipids of the photosynthetic membrane are synthesized by parallel pathways associated with the endoplasmic reticulum (ER) and the chloroplast envelope membranes. Lipids derived from the two pathways are distinguished by their acyl-constituents. Following this plant paradigm, the prevalent acyl composition of chloroplast lipids suggests that Chlamydomonas reinhardtii (Chlamydomonas) does not use the ER pathway; however, the Chlamydomonas genome encodes presumed plant orthologues of a chloroplast lipid transporter consisting of TGD (TRIGALACTOSYLDIACYLGLYCEROL) proteins that are required for ER-to-chloroplast lipid trafficking in plants. To resolve this conundrum, we identified a mutant of Chlamydomonas deleted in the TGD2 gene and characterized the respective protein, CrTGD2. Notably, the viability of the mutant was reduced, showing the importance of CrTGD2. Galactoglycerolipid metabolism was altered in the tgd2 mutant with monogalactosyldiacylglycerol (MGDG) synthase activity being strongly stimulated. We hypothesize this to be a result of phosphatidic acid accumulation in the chloroplast outer envelope membrane, the location of MGDG synthase in Chlamydomonas. Concomitantly, increased conversion of MGDG into triacylglycerol (TAG) was observed. This TAG accumulated in lipid droplets in the tgd2 mutant under normal growth conditions. Labeling kinetics indicate that Chlamydomonas can import lipid precursors from the ER, a process that is impaired in the tgd2 mutant.
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Affiliation(s)
- Jaruswan Warakanont
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Chia-Hong Tsai
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Elena J S Michel
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA
| | - George R Murphy
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Peter Y Hsueh
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Rebecca L Roston
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Barbara B Sears
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Christoph Benning
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, 48824, USA
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17
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Iwai M, Hori K, Sasaki-Sekimoto Y, Shimojima M, Ohta H. Manipulation of oil synthesis in Nannochloropsis strain NIES-2145 with a phosphorus starvation-inducible promoter from Chlamydomonas reinhardtii. Front Microbiol 2015; 6:912. [PMID: 26441858 PMCID: PMC4561341 DOI: 10.3389/fmicb.2015.00912] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/19/2015] [Indexed: 01/04/2023] Open
Abstract
Microalgae accumulate triacylglycerols (TAGs) under conditions of nutrient stress. Phosphorus (P) starvation induces the accumulation of TAGs, and the cells under P starvation maintain growth through photosynthesis. We recently reported that P starvation–dependent overexpression of type-2 diacylglycerol acyl-CoA acyltransferase (CrDGTT4) from Chlamydomonas reinhardtii using a sulfoquinovosyldiacylglycerol synthase 2 (SQD2) promoter, which has increased activity during P starvation, enhances TAG accumulation in C. reinhardtii cells. As a result, the content of C18:1 fatty acid, a preferred substrate of CrDGTT4, is increased in TAGs. Here we isolated genes encoding SQD2 from strain NIES-2145 of the eustigmatophyte Nannochloropsis and showed that their expression, like that in C. reinhardtii, was up-regulated during P starvation. To enhance oil accumulation under P starvation, we transformed pCrSQD2-CrDGTT4 into Nannochloropsis strain NIES-2145. The transformants had a fatty acid composition that was more similar to that of C. reinhardtii, which resulted in enhanced TAG accumulation and higher 18:1(9) content. The results indicated that the P starvation–inducible promoter of C. reinhardtii was able to drive expression of the CrDGTT4 gene in Nannochloropsis strain NIES-2145 under P starvation. We conclude that the heterologous CrSQD2 promoter is effective in manipulating TAG synthesis in Nannochloropsis during P starvation.
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Affiliation(s)
- Masako Iwai
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology Yokohama, Japan ; JST CREST Tokyo, Japan
| | - Koichi Hori
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology Yokohama, Japan ; JST CREST Tokyo, Japan
| | | | - Mie Shimojima
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology Yokohama, Japan
| | - Hiroyuki Ohta
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology Yokohama, Japan ; JST CREST Tokyo, Japan ; Earth-Life Science Institute, Tokyo Institute of Technology Tokyo, Japan
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18
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Hung CH, Endo K, Kobayashi K, Nakamura Y, Wada H. Characterization of Chlamydomonas reinhardtii phosphatidylglycerophosphate synthase in Synechocystis sp. PCC 6803. Front Microbiol 2015; 6:842. [PMID: 26379630 PMCID: PMC4547039 DOI: 10.3389/fmicb.2015.00842] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 07/31/2015] [Indexed: 12/22/2022] Open
Abstract
Phosphatidylglycerol (PG) is an indispensable phospholipid class with photosynthetic function in plants and cyanobacteria. However, its biosynthesis in eukaryotic green microalgae is poorly studied. Here, we report the isolation and characterization of two homologs (CrPGP1 and CrPGP2) of phosphatidylglycerophosphate synthase (PGPS), the rate-limiting enzyme in PG biosynthesis, in Chlamydomonas reinhardtii. Heterologous complementation of Synechocystis sp. PCC 6803 pgsA mutant by CrPGP1 and CrPGP2 rescued the PG-dependent growth phenotype, but the PG level and its fatty acid composition were not fully rescued in the complemented strains. As well, oxygen evolution activity was not fully recovered, although electron transport activity of photosystem II was restored to the wild-type level. Gene expression study of CrPGP1 and CrPGP2 in nutrient-starved C. reinhardtii showed differential response to phosphorus and nitrogen deficiency. Taken together, these results highlight the distinct and overlapping function of PGPS in cyanobacteria and eukaryotic algae.
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Affiliation(s)
- Chun-Hsien Hung
- Institute of Plant and Microbial Biology, Academia Sinica Taipei, Taiwan
| | - Kaichiro Endo
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo Tokyo, Japan
| | - Koichi Kobayashi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo Tokyo, Japan
| | - Yuki Nakamura
- Institute of Plant and Microbial Biology, Academia Sinica Taipei, Taiwan ; PRESTO, Japan Science and Technology Agency Saitama, Japan
| | - Hajime Wada
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo Tokyo, Japan ; CREST, Japan Science and Technology Agency Saitama, Japan
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19
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Avidan O, Brandis A, Rogachev I, Pick U. Enhanced acetyl-CoA production is associated with increased triglyceride accumulation in the green alga Chlorella desiccata. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:3725-35. [PMID: 25922486 PMCID: PMC4473976 DOI: 10.1093/jxb/erv166] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Triglycerides (TAGs) from microalgae can be utilized as food supplements and for biodiesel production, but little is known about the regulation of their biosynthesis. This work aimed to test the relationship between acetyl-CoA (Ac-CoA) levels and TAG biosynthesis in green algae under nitrogen deprivation. A novel, highly sensitive liquid chromatography mass spectrometry (LC-MS/MS) technique enabled us to determine the levels of Ac-CoA, malonyl-CoA, and unacetylated (free) CoA in green microalgae. A comparative study of three algal species that differ in TAG accumulation levels shows that during N starvation, Ac-CoA levels rapidly rise, preceding TAG accumulation in all tested species. The levels of Ac-CoA in the high TAG accumulator Chlorella desiccata exceed the levels in the moderate TAG accumulators Dunaliella tertiolecta and Chlamydomonas reinhardtii. Similarly, malonyl-CoA and free CoA levels also increase, but to lower extents. Calculated cellular concentrations of Ac-CoA are far lower than reported K mAc-CoA values of plastidic Ac-CoA carboxylase (ptACCase) in plants. Transcript level analysis of plastidic pyruvate dehydrogenase (ptPDH), the major chloroplastic Ac-CoA producer, revealed rapid induction in parallel with Ac-CoA accumulation in C. desiccata, but not in D. tertiolecta or C. reinhardtii. It is proposed that the capacity to accumulate high TAG levels in green algae critically depends on their ability to divert carbon flow towards Ac-CoA. This requires elevation of the chloroplastic CoA pool level and enhancement of Ac-CoA biosynthesis. These conclusions may have important implications for future genetic manipulation to enhance TAG biosynthesis in green algae.
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Affiliation(s)
- Omri Avidan
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alexander Brandis
- Biological Services Unit, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ilana Rogachev
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Uri Pick
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
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20
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Li-Beisson Y, Beisson F, Riekhof W. Metabolism of acyl-lipids in Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:504-522. [PMID: 25660108 DOI: 10.1111/tpj.12787] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 01/24/2015] [Accepted: 02/02/2015] [Indexed: 05/03/2023]
Abstract
Microalgae are emerging platforms for production of a suite of compounds targeting several markets, including food, nutraceuticals, green chemicals, and biofuels. Many of these products, such as biodiesel or polyunsaturated fatty acids (PUFAs), derive from lipid metabolism. A general picture of lipid metabolism in microalgae has been deduced from well characterized pathways of fungi and land plants, but recent advances in molecular and genetic analyses of microalgae have uncovered unique features, pointing out the necessity to study lipid metabolism in microalgae themselves. In the past 10 years, in addition to its traditional role as a model for photosynthetic and flagellar motility processes, Chlamydomonas reinhardtii has emerged as a model organism to study lipid metabolism in green microalgae. Here, after summarizing data on total fatty acid composition, distribution of acyl-lipid classes, and major acyl-lipid molecular species found in C. reinhardtii, we review the current knowledge on the known or putative steps for fatty acid synthesis, glycerolipid desaturation and assembly, membrane lipid turnover, and oil remobilization. A list of characterized or putative enzymes for the major steps of acyl-lipid metabolism in C. reinhardtii is included, and subcellular localizations and phenotypes of associated mutants are discussed. Biogenesis and composition of Chlamydomonas lipid droplets and the potential importance of lipolytic processes in increasing cellular oil content are also highlighted.
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Affiliation(s)
- Yonghua Li-Beisson
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut de Biologie Environnementale et Biotechnologie, CEA Cadarache, 13108, Saint-Paul-lez-Durance, France
- Centre National de la Recherche Scientifique (CNRS), 13108, Saint-Paul-lez-Durance, France
- Aix-Marseille Université, UMR 7265, 13284, Marseille, France
| | - Fred Beisson
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut de Biologie Environnementale et Biotechnologie, CEA Cadarache, 13108, Saint-Paul-lez-Durance, France
- Centre National de la Recherche Scientifique (CNRS), 13108, Saint-Paul-lez-Durance, France
- Aix-Marseille Université, UMR 7265, 13284, Marseille, France
| | - Wayne Riekhof
- School of Biological Sciences and Center for Biological Chemistry, University of Nebraska - Lincoln, Lincoln, NE, 68588, USA
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21
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Kleczkowski LA, Decker D. Sugar Activation for Production of Nucleotide Sugars as Substrates for Glycosyltransferases in Plants. J Appl Glycosci (1999) 2015. [DOI: 10.5458/jag.jag.jag-2015_003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Affiliation(s)
| | - Daniel Decker
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University
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22
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Fang SC, Chung CL, Chen CH, Lopez-Paz C, Umen JG. Defects in a new class of sulfate/anion transporter link sulfur acclimation responses to intracellular glutathione levels and cell cycle control. PLANT PHYSIOLOGY 2014; 166:1852-68. [PMID: 25361960 PMCID: PMC4256884 DOI: 10.1104/pp.114.251009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 10/29/2014] [Indexed: 05/18/2023]
Abstract
We previously identified a mutation, suppressor of mating type locus3 15-1 (smt15-1), that partially suppresses the cell cycle defects caused by loss of the retinoblastoma tumor suppressor-related protein encoded by the MAT3 gene in Chlamydomonas reinhardtii. smt15-1 single mutants were also found to have a cell cycle defect leading to a small-cell phenotype. SMT15 belongs to a previously uncharacterized subfamily of putative membrane-localized sulfate/anion transporters that contain a sulfate transporter domain and are found in a widely distributed subset of eukaryotes and bacteria. Although we observed that smt15-1 has a defect in acclimation to sulfur-limited growth conditions, sulfur acclimation (sac) mutants, which are more severely defective for acclimation to sulfur limitation, do not have cell cycle defects and cannot suppress mat3. Moreover, we found that smt15-1, but not sac mutants, overaccumulates glutathione. In wild-type cells, glutathione fluctuated during the cell cycle, with highest levels in mid G1 phase and lower levels during S and M phases, while in smt15-1, glutathione levels remained elevated during S and M. In addition to increased total glutathione levels, smt15-1 cells had an increased reduced-to-oxidized glutathione redox ratio throughout the cell cycle. These data suggest a role for SMT15 in maintaining glutathione homeostasis that impacts the cell cycle and sulfur acclimation responses.
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Affiliation(s)
- Su-Chiung Fang
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
| | - Chin-Lin Chung
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
| | - Chun-Han Chen
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
| | - Cristina Lopez-Paz
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
| | - James G Umen
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan County 741, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-C.F., C.-L.C., C.-H.C.);Institute of Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (C.-L.C.); andDonald Danforth Plant Science Center, St. Louis, Missouri 63132 (C.L.-P., J.G.U.)
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23
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Iwai M, Ikeda K, Shimojima M, Ohta H. Enhancement of extraplastidic oil synthesis in Chlamydomonas reinhardtii using a type-2 diacylglycerol acyltransferase with a phosphorus starvation-inducible promoter. PLANT BIOTECHNOLOGY JOURNAL 2014; 12:808-19. [PMID: 24909748 PMCID: PMC4160818 DOI: 10.1111/pbi.12210] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 04/23/2014] [Accepted: 05/06/2014] [Indexed: 05/03/2023]
Abstract
When cultivated under stress conditions, many plants and algae accumulate oil. The unicellular green microalga Chlamydomonas reinhardtii accumulates neutral lipids (triacylglycerols; TAGs) during nutrient stress conditions. Temporal changes in TAG levels in nitrogen (N)- and phosphorus (P)-starved cells were examined to compare the effects of nutrient depletion on TAG accumulation in C. reinhardtii. TAG accumulation and fatty acid composition were substantially changed depending on the cultivation stage before nutrient starvation. Profiles of TAG accumulation also differed between N and P starvation. Logarithmic-growth-phase cells diluted into fresh medium showed substantial TAG accumulation with both N and P deprivation. N deprivation induced formation of oil droplets concomitant with the breakdown of thylakoid membranes. In contrast, P deprivation substantially induced accumulation of oil droplets in the cytosol and maintaining thylakoid membranes. As a consequence, P limitation accumulated more TAG both per cell and per culture medium under these conditions. To enhance oil accumulation under P deprivation, we constructed a P deprivation-dependent overexpressor of a Chlamydomonas type-2 diacylglycerol acyl-CoA acyltransferase (DGTT4) using a sulphoquinovosyldiacylglycerol 2 (SQD2) promoter, which was up-regulated during P starvation. The transformant strongly enhanced TAG accumulation with a slight increase in 18 : 1 content, which is a preferred substrate of DGTT4. These results demonstrated enhanced TAG accumulation using a P starvation-inducible promoter.
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Affiliation(s)
- Masako Iwai
- Center for Biological Resources and Informatics, Tokyo Institute of TechnologyMidori-ku, Yokohama, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)Chiyoda-ku, Tokyo, Japan
| | - Keiko Ikeda
- Biomaterial Analysis Center, Technical Department, Tokyo Institute of TechnologyMidori-ku, Yokohama, Japan
| | - Mie Shimojima
- Center for Biological Resources and Informatics, Tokyo Institute of TechnologyMidori-ku, Yokohama, Japan
| | - Hiroyuki Ohta
- Center for Biological Resources and Informatics, Tokyo Institute of TechnologyMidori-ku, Yokohama, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)Chiyoda-ku, Tokyo, Japan
- Earth-Life Science Institute, Tokyo Institute of TechnologyMeguro-ku, Tokyo, Japan
- *Correspondence (Tel 81 45 924 5736; fax 81 45 924 5823; email )
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24
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Johnson EA, Rice S, Preimesberger MR, Nye DB, Gilevicius L, Wenke BB, Brown JM, Witman GB, Lecomte JTJ. Characterization of THB1, a Chlamydomonas reinhardtii truncated hemoglobin: linkage to nitrogen metabolism and identification of lysine as the distal heme ligand. Biochemistry 2014; 53:4573-89. [PMID: 24964018 PMCID: PMC4108185 DOI: 10.1021/bi5005206] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/23/2014] [Indexed: 12/21/2022]
Abstract
The nuclear genome of the model organism Chlamydomonas reinhardtii contains genes for a dozen hemoglobins of the truncated lineage. Of those, THB1 is known to be expressed, but the product and its function have not yet been characterized. We present mutagenesis, optical, and nuclear magnetic resonance data for the recombinant protein and show that at pH near neutral in the absence of added ligand, THB1 coordinates the heme iron with the canonical proximal histidine and a distal lysine. In the cyanomet state, THB1 is structurally similar to other known truncated hemoglobins, particularly the heme domain of Chlamydomonas eugametos LI637, a light-induced chloroplastic hemoglobin. Recombinant THB1 is capable of binding nitric oxide (NO(•)) in either the ferric or ferrous state and has efficient NO(•) dioxygenase activity. By using different C. reinhardtii strains and growth conditions, we demonstrate that the expression of THB1 is under the control of the NIT2 regulatory gene and that the hemoglobin is linked to the nitrogen assimilation pathway.
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Affiliation(s)
- Eric A. Johnson
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Selena
L. Rice
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | | | - Dillon B. Nye
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Lukas Gilevicius
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Belinda B. Wenke
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jason M. Brown
- Department
of Cell and Developmental Biology, University
of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - George B. Witman
- Department
of Cell and Developmental Biology, University
of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - Juliette T. J. Lecomte
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
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25
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Li N, Wang L, Zhang W, Takechi K, Takano H, Lin X. Overexpression of UDP-glucose pyrophosphorylase from Larix gmelinii enhances vegetative growth in transgenic Arabidopsis thaliana. PLANT CELL REPORTS 2014; 33:779-91. [PMID: 24408396 DOI: 10.1007/s00299-013-1558-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 12/19/2013] [Accepted: 12/20/2013] [Indexed: 05/11/2023]
Abstract
A UDP-glucose pyrophosphorylase gene ( LgUGPase ) was identified from Larix gmelinii, and its function in enhancing vegetative growth and cellulose biosynthesis was confirmed by analyzing transgenic Arabidopsis thaliana overexpressed LgUGPase . UDP-glucose pyrophosphorylase (UGPase), an important regulatory enzyme in carbohydrate metabolism, catalyzes the reversible production of glucose 1-phosphate and the conversion of uridine triphosphate to uridine diphosphate glucose and pyrophosphate. In this study, a larch UGPase (LgUGPase) gene was isolated from Larix gmelinii. The 1,443-bp open reading frame encodes a protein of 480 amino acids with a predicted molecular weight of 53.7 kDa and shows striking sequence similarity to UGPase proteins from Pinus taeda and Picea sitchensis. Semiquantitative reverse transcription-polymerase chain reaction showed that the LgUGPase gene was expressed primarily in the larch stem in addition to its root and leaf. Southern blot analysis indicated that LgUGPase is encoded by two genes in the L. gmelinii genome. Overexpression of LgUGPase enhanced vegetative growth in transgenic Arabidopsis and increased the contents of soluble sugars and cellulose, and thickened parenchyma cell walls. These results revealed that L. gmelinii UGPase participates in sucrose/polysaccharide metabolism and cell wall biosynthesis, suggesting that LgUGPase may be a good candidate gene for improvement of fiber cell development in plants.
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Affiliation(s)
- Ningning Li
- College of Life Sciences, Inner Mongolia University, 235 Daxuexi Road, Hohhot, 010021, China
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26
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Aksoy M, Pootakham W, Pollock SV, Moseley JL, González-Ballester D, Grossman AR. Tiered regulation of sulfur deprivation responses in Chlamydomonas reinhardtii and identification of an associated regulatory factor. PLANT PHYSIOLOGY 2013; 162:195-211. [PMID: 23482872 PMCID: PMC3641202 DOI: 10.1104/pp.113.214593] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 03/08/2013] [Indexed: 05/19/2023]
Abstract
During sulfur (S) deprivation, the unicellular alga Chlamydomonas reinhardtii exhibits increased expression of numerous genes. These genes encode proteins associated with sulfate (SO4(2-)) acquisition and assimilation, alterations in cellular metabolism, and internal S recycling. Administration of the cytoplasmic translational inhibitor cycloheximide prevents S deprivation-triggered accumulation of transcripts encoding arylsulfatases (ARS), an extracellular polypeptide that may be important for cell wall biosynthesis (ECP76), a light-harvesting protein (LHCBM9), the selenium-binding protein, and the haloperoxidase (HAP2). In contrast, the rapid accumulation of transcripts encoding high-affinity SO4(2-) transporters is not affected. These results suggest that there are two tiers of transcriptional regulation associated with S deprivation responses: the first is protein synthesis independent, while the second requires de novo protein synthesis. A mutant designated ars73a exhibited low ARS activity and failed to show increases in ECP76, LHCBM9, and HAP2 transcripts (among others) in response to S deprivation; increases in transcripts encoding the SO4(2-) transporters were not affected. These results suggest that the ARS73a protein, which has no known activity but might be a transcriptional regulator, is required for the expression of genes associated with the second tier of transcriptional regulation. Analysis of the ars73a strain has helped us generate a model that incorporates a number of complexities associated with S deprivation responses in C. reinhardtii.
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Affiliation(s)
- Munevver Aksoy
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
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27
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Li X, Moellering ER, Liu B, Johnny C, Fedewa M, Sears BB, Kuo MH, Benning C. A galactoglycerolipid lipase is required for triacylglycerol accumulation and survival following nitrogen deprivation in Chlamydomonas reinhardtii. THE PLANT CELL 2012; 24:4670-86. [PMID: 23161887 PMCID: PMC3531859 DOI: 10.1105/tpc.112.105106] [Citation(s) in RCA: 218] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 10/16/2012] [Accepted: 10/27/2012] [Indexed: 05/17/2023]
Abstract
Following N deprivation, microalgae accumulate triacylglycerols (TAGs). To gain mechanistic insights into this phenomenon, we identified mutants with reduced TAG content following N deprivation in the model alga Chlamydomonas reinhardtii. In one of the mutants, the disruption of a galactoglycerolipid lipase-encoding gene, designated PLASTID GALACTOGLYCEROLIPID DEGRADATION1 (PGD1), was responsible for the primary phenotype: reduced TAG content, altered TAG composition, and reduced galactoglycerolipid turnover. The recombinant PGD1 protein, which was purified from Escherichia coli extracts, hydrolyzed monogalactosyldiacylglycerol into its lyso-lipid derivative. In vivo pulse-chase labeling identified galactoglycerolipid pools as a major source of fatty acids esterified in TAGs following N deprivation. Moreover, the fatty acid flux from plastid lipids to TAG was decreased in the pgd1 mutant. Apparently, de novo-synthesized fatty acids in Chlamydomonas reinhardtii are, at least partially, first incorporated into plastid lipids before they enter TAG synthesis. As a secondary effect, the pgd1 mutant exhibited a loss of viability following N deprivation, which could be avoided by blocking photosynthetic electron transport. Thus, the pgd1 mutant provides evidence for an important biological function of TAG synthesis following N deprivation, namely, relieving a detrimental overreduction of the photosynthetic electron transport chain.
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Affiliation(s)
- Xiaobo Li
- Department of Energy–Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Eric R. Moellering
- Department of Energy–Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Bensheng Liu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Cassandra Johnny
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Marie Fedewa
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Barbara B. Sears
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Min-Hao Kuo
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Christoph Benning
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
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28
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Rapid triacylglycerol turnover in Chlamydomonas reinhardtii requires a lipase with broad substrate specificity. EUKARYOTIC CELL 2012; 11:1451-62. [PMID: 23042128 DOI: 10.1128/ec.00268-12] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
When deprived of nitrogen (N), the photosynthetic microalga Chlamydomonas reinhardtii accumulates large quantities of triacylglycerols (TAGs), making it a promising source of biofuel. Prominent transcriptional changes associated with the conditions leading to TAG accumulation have been found, suggesting that the key enzymes for TAG metabolism might be among those that fluctuate in their expression during TAG synthesis and breakdown. Using a Saccharomyces cerevisiae lipase null mutant strain for functional complementation, we identified the CrLIP1 gene from Chlamydomonas based on its ability to suppress the lipase deficiency-related phenotypes of the yeast mutant. In Chlamydomonas, an inverse correlation was found between the CrLIP1 transcript level and TAG abundance when Chlamydomonas cultures were reversibly deprived of N. The CrLIP1 protein expressed and purified from Escherichia coli exhibited lipolytic activity against diacylglycerol (DAG) and polar lipids. The lipase domain of CrLIP1 is most similar to two human DAG lipases, DAGLα and DAGLβ. The involvement of CrLIP1 in Chlamydomonas TAG hydrolysis was corroborated by reducing the abundance of the CrLIP1 transcript with an artificial micro-RNA, which resulted in an apparent delay in TAG lipolysis when N was resupplied. Together, these data suggest that CrLIP1 facilitates TAG turnover in Chlamydomonas primarily by degrading the DAG presumably generated from TAG hydrolysis.
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29
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Shu L, Hu Z. Characterization and differential expression of microRNAs elicited by sulfur deprivation in Chlamydomonas reinhardtii. BMC Genomics 2012; 13:108. [PMID: 22439676 PMCID: PMC3441669 DOI: 10.1186/1471-2164-13-108] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Accepted: 03/22/2012] [Indexed: 11/20/2022] Open
Abstract
Background microRNAs (miRNAs) have been found to play an essential role in the modulation of numerous biological processes in eukaryotes. Chlamydomonas reinhardtii is an ideal model organism for the study of many metabolic processes including responses to sulfur-deprivation. We used a deep sequencing platform to extensively profile and identify changes in the miRNAs expression that occurred under sulfur-replete and sulfur-deprived conditions. The aim of our research was to characterize the differential expression of Chlamydomonas miRNAs under sulfur-deprived conditions, and subsequently, the target genes of miRNA involved in sulfur-deprivation were further predicted and analyzed. Results By using high-throughput sequencing, we characterized the microRNA transcriptomes under sulphur-replete and sulfur-deprived conditions in Chlamydomonas reinhardtii. We predicted a total of 310 miRNAs which included 85 known miRNAs and 225 novel miRNAs. 13 miRNAs were the specific to the sulfur-deprived conditions. 47 miRNAs showed significantly differential expressions responding to sulfur-deprivation, and most were up-regulated in the small RNA libraries with sulfur-deprivation. Using a web-based integrated system (Web MicroRNAs Designer 3) and combing the former information from a transcriptome of Chlamydomonas reinhardtii, 22 miRNAs and their targets involved in metabolism regulation with sulfur-deprivation were verified. Conclusions Our results indicate that sulfur-deprivation may have a significant influence on small RNA expression patterns, and the differential expressions of miRNAs and interactions between miRNA and its targets might further reveal the molecular mechanism responding to sulfur-deprivation in Chlamydomonas reinhardtii.
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Affiliation(s)
- Longfei Shu
- Department of Aquatic Ecology, Eawag, Switzerland
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30
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Nedelcu AM. The evolution of self during the transition to multicellularity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 738:14-30. [PMID: 22399371 DOI: 10.1007/978-1-4614-1680-7_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The notion of ' self' is intrinsically linked to the concepts of identity and individuality. During evolutionary transitions in individuality-such as, for instance, during the origin of the first cell, the origin of the eukaryotic cell and the origin of multicellular individuals-new kinds of individuals emerged from the interaction of previously independent entities. The question discussed here is: How can new types of individuals with qualities that cannot be reduced to the properties of their parts be created at a higher level? This question is addressed in the context of the transition to multicellularity and using the volvocine green algae-a group of closely related unicellular and multicellular species with various degrees of physiological and reproductive unity-as a model system. In this chapter, we review our framework to addressing the evolution of individuality during the transition to multicellularity, focusing on the reorganization of general life-traits and cellular processes and the cooption of environmentally-induced responses.
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Affiliation(s)
- Aurora M Nedelcu
- Biology Department, University of New Brunswick, Fredericton, New Brunswick, Canada.
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31
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Nussaume L, Kanno S, Javot H, Marin E, Pochon N, Ayadi A, Nakanishi TM, Thibaud MC. Phosphate Import in Plants: Focus on the PHT1 Transporters. FRONTIERS IN PLANT SCIENCE 2011; 2:83. [PMID: 22645553 PMCID: PMC3355772 DOI: 10.3389/fpls.2011.00083] [Citation(s) in RCA: 281] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 11/03/2011] [Indexed: 05/17/2023]
Abstract
The main source of phosphorus for plants is inorganic phosphate (Pi), which is characterized by its poor availability and low mobility. Uptake of this element from the soil relies heavily upon the PHT1 transporters, a specific family of plant plasma membrane proteins that were identified by homology with the yeast PHO84 Pi transporter. Since the discovery of PHT1 transporters in 1996, various studies have revealed that their function is controlled by a highly complex network of regulation. This review will summarize the current state of research on plant PHT1 multigenic families, including physiological, biochemical, molecular, cellular, and genetics studies.
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Affiliation(s)
- Laurent Nussaume
- IBEB-SBVME Laboratoire de Biologie du Développement des Plantes, UMR6191 CNRS-Commissariat à l’Energie Atomique et aux Energies Alternatives Cadarache, Université Aix-Marseille, F-13108 Saint-Paul-lez-DuranceFrance
| | - Satomi Kanno
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-kuTokyo, Japan 113-8657
| | - Hélène Javot
- IBEB-SBVME Laboratoire de Biologie du Développement des Plantes, UMR6191 CNRS-Commissariat à l’Energie Atomique et aux Energies Alternatives Cadarache, Université Aix-Marseille, F-13108 Saint-Paul-lez-DuranceFrance
| | - Elena Marin
- IBEB-SBVME Laboratoire de Biologie du Développement des Plantes, UMR6191 CNRS-Commissariat à l’Energie Atomique et aux Energies Alternatives Cadarache, Université Aix-Marseille, F-13108 Saint-Paul-lez-DuranceFrance
| | - Nathalie Pochon
- IBEB-SBVME Laboratoire de Biologie du Développement des Plantes, UMR6191 CNRS-Commissariat à l’Energie Atomique et aux Energies Alternatives Cadarache, Université Aix-Marseille, F-13108 Saint-Paul-lez-DuranceFrance
| | - Amal Ayadi
- IBEB-SBVME Laboratoire de Biologie du Développement des Plantes, UMR6191 CNRS-Commissariat à l’Energie Atomique et aux Energies Alternatives Cadarache, Université Aix-Marseille, F-13108 Saint-Paul-lez-DuranceFrance
| | - Tomoko M. Nakanishi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-kuTokyo, Japan 113-8657
| | - Marie-Christine Thibaud
- IBEB-SBVME Laboratoire de Biologie du Développement des Plantes, UMR6191 CNRS-Commissariat à l’Energie Atomique et aux Energies Alternatives Cadarache, Université Aix-Marseille, F-13108 Saint-Paul-lez-DuranceFrance
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32
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Abstract
Plant pyrophosphorylases that are capable of producing UDP-sugars, key precursors for glycosylation reactions, include UDP-glucose pyrophosphorylases (A- and B-type), UDP-sugar pyrophosphorylase and UDP-N-acetylglucosamine pyrophosphorylase. Although not sharing significant homology at the amino acid sequence level, the proteins share a common structural blueprint. Their structures are characterized by the presence of the Rossmann fold in the central (catalytic) domain linked to enzyme-specific N-terminal and C-terminal domains, which may play regulatory functions. Molecular mobility between these domains plays an important role in substrate binding and catalysis. Evolutionary relationships and the role of (de)oligomerization as a regulatory mechanism are discussed.
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33
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Wang Q, Zhang X, Li F, Hou Y, Liu X, Zhang X. Identification of a UDP-glucose pyrophosphorylase from cotton (Gossypium hirsutum L.) involved in cellulose biosynthesis in Arabidopsis thaliana. PLANT CELL REPORTS 2011; 30:1303-12. [PMID: 21373794 DOI: 10.1007/s00299-011-1042-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 02/14/2011] [Accepted: 02/20/2011] [Indexed: 05/06/2023]
Abstract
UDP-glucose pyrophosphorylase is an important regulatory enzyme for the development of plants and a critical enzyme in synthesis of glycogen. Here, we reported the cloning of a full-length UGP cDNA from cotton, named GhUGP. Real-time PCR analysis indicated the GhUGP expression in root, stem, leaf and flower of cotton, with a higher level in flower and root. The transcription level of GhUGP depended on sucrose and light in short time and increased under low temperature, but decreased in O(2) deficiency. Interestingly, the expression of GhUGP was significantly up-regulated after ethylene induction in cotton ovules. The over-expression of the GhUGP in Arabidopsis showed discrepant phenotype: increase in height and growth rate when compared with control lines. What is more, the transgenic Arabidopsis had increased contents of soluble sugars, starch and cellulose, but not in lignin content. Collectively, these results indicate that cotton UGPase participates in sucrose/polysaccharides metabolism and cell wall biosynthesis and provide theoretical deduction supporting GhUGP as a good candidate gene for improving the development of cotton fibers cell.
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Affiliation(s)
- Qinghua Wang
- College of Science, China Agricultural University, 2 West Road, Yuanmingyuan, Haidian District, Beijing, China
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34
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Karpowicz SJ, Prochnik SE, Grossman AR, Merchant SS. The GreenCut2 resource, a phylogenomically derived inventory of proteins specific to the plant lineage. J Biol Chem 2011; 286:21427-39. [PMID: 21515685 PMCID: PMC3122202 DOI: 10.1074/jbc.m111.233734] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 04/11/2011] [Indexed: 11/06/2022] Open
Abstract
The plastid is a defining structure of photosynthetic eukaryotes and houses many plant-specific processes, including the light reactions, carbon fixation, pigment synthesis, and other primary metabolic processes. Identifying proteins associated with catalytic, structural, and regulatory functions that are unique to plastid-containing organisms is necessary to fully define the scope of plant biochemistry. Here, we performed phylogenomics on 20 genomes to compile a new inventory of 597 nucleus-encoded proteins conserved in plants and green algae but not in non-photosynthetic organisms. 286 of these proteins are of known function, whereas 311 are not characterized. This inventory was validated as applicable and relevant to diverse photosynthetic eukaryotes using an additional eight genomes from distantly related plants (including Micromonas, Selaginella, and soybean). Manual curation of the known proteins in the inventory established its importance to plastid biochemistry. To predict functions for the 52% of proteins of unknown function, we used sequence motifs, subcellular localization, co-expression analysis, and RNA abundance data. We demonstrate that 18% of the proteins in the inventory have functions outside the plastid and/or beyond green tissues. Although 32% of proteins in the inventory have homologs in all cyanobacteria, unexpectedly, 30% are eukaryote-specific. Finally, 8% of the proteins of unknown function share no similarity to any characterized protein and are plant lineage-specific. We present this annotated inventory of 597 proteins as a resource for functional analyses of plant-specific biochemistry.
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Affiliation(s)
| | - Simon E. Prochnik
- the United States Department of Energy Joint Genome Institute, Walnut Creek, California 94598, and
| | - Arthur R. Grossman
- the Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Sabeeha S. Merchant
- From the Department of Chemistry and Biochemistry and
- Institute for Genomics and Proteomics, UCLA, Los Angeles, California 90095
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35
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Bienvenut WV, Espagne C, Martinez A, Majeran W, Valot B, Zivy M, Vallon O, Adam Z, Meinnel T, Giglione C. Dynamics of post-translational modifications and protein stability in the stroma of Chlamydomonas reinhardtii chloroplasts. Proteomics 2011; 11:1734-50. [PMID: 21462344 DOI: 10.1002/pmic.201000634] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 11/10/2010] [Accepted: 11/29/2010] [Indexed: 01/09/2023]
Abstract
The proteome of any system is a dynamic entity dependent on the intracellular concentration of the entire set of expressed proteins. In turn, this whole protein concentration will be reliant on the stability/turnover of each protein as dictated by their relative rates of synthesis and degradation. In this study, we have investigated the dynamics of the stromal proteome in the model organism Chlamydomonas reinhardtii by characterizing the half-life of the whole set of proteins. 2-DE stromal proteins profiling was set up and coupled with MS analyses. These identifications featuring an average of 26% sequence coverage and eight non-redundant peptides per protein have been obtained for 600 independent samples related to 253 distinct spots. An interactive map of the global stromal proteome, of 274 distinct protein variants is now available on-line at http://www.isv.cnrs-gif.fr/gel2dv2/. N-α-terminal-Acetylation (NTA) was noticed to be the most frequently detectable post-translational modification, and new experimental data related to the chloroplastic transit peptide cleavage site was obtained. Using this data set supplemented with series of pulse-chase experiments, elements directing the relationship between half-life and N-termini were analyzed. Positive correlation between NTA and protein half-life suggests that NTA could contribute to protein stabilization in the stroma.
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36
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Pootakham W, Gonzalez-Ballester D, Grossman AR. Identification and regulation of plasma membrane sulfate transporters in Chlamydomonas. PLANT PHYSIOLOGY 2010; 153:1653-68. [PMID: 20498339 PMCID: PMC2923900 DOI: 10.1104/pp.110.157875] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 05/21/2010] [Indexed: 05/18/2023]
Abstract
Chlamydomonas (Chlamydomonas reinhardtii) exhibits several responses following exposure to sulfur (S)-deprivation conditions, including an increased efficiency of import and assimilation of the sulfate anion (SO(4)(2-)). Aspects of SO(4)(2-) transport during S-replete and S-depleted conditions were previously studied, although the transporters had not been functionally identified. We employed a reverse genetics approach to identify putative SO(4)(2-) transporters, examine their regulation, establish their biogenesis and subcellular locations, and explore their functionality. Upon S starvation of wild-type Chlamydomonas cells, the accumulation of transcripts encoding the putative SO(4)(2-) transporters SLT1 (for SAC1-like transporter 1), SLT2, and SULTR2 markedly increased, suggesting that these proteins function in high-affinity SO(4)(2-) transport. The Chlamydomonas sac1 and snrk2.1 mutants (defective for acclimation to S deprivation) exhibited much less of an increase in the levels of SLT1, SLT2, and SULTR2 transcripts and their encoded proteins in response to S deprivation compared with wild-type cells. All three transporters were localized to the plasma membrane, and their rates of turnover were significantly impacted by S availability; the turnover of SLT1 and SLT2 was proteasome dependent, while that of SULTR2 was proteasome independent. Finally, mutants identified for each of the S-deprivation-responsive transporters were used to establish their critical role in the transport of SO(4)(2-) into S-deprived cells.
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Affiliation(s)
- Wirulda Pootakham
- Department of Biology, Stanford University, Stanford, California 94305-5020, USA.
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González-Ballester D, Casero D, Cokus S, Pellegrini M, Merchant SS, Grossman AR. RNA-seq analysis of sulfur-deprived Chlamydomonas cells reveals aspects of acclimation critical for cell survival. THE PLANT CELL 2010; 22:2058-84. [PMID: 20587772 PMCID: PMC2910963 DOI: 10.1105/tpc.109.071167] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 04/01/2010] [Accepted: 05/18/2010] [Indexed: 05/18/2023]
Abstract
The Chlamydomonas reinhardtii transcriptome was characterized from nutrient-replete and sulfur-depleted wild-type and snrk2.1 mutant cells. This mutant is null for the regulatory Ser-Thr kinase SNRK2.1, which is required for acclimation of the alga to sulfur deprivation. The transcriptome analyses used microarray hybridization and RNA-seq technology. Quantitative RT-PCR evaluation of the results obtained by these techniques showed that RNA-seq reports a larger dynamic range of expression levels than do microarray hybridizations. Transcripts responsive to sulfur deprivation included those encoding proteins involved in sulfur acquisition and assimilation, synthesis of sulfur-containing metabolites, Cys degradation, and sulfur recycling. Furthermore, we noted potential modifications of cellular structures during sulfur deprivation, including the cell wall and complexes associated with the photosynthetic apparatus. Moreover, the data suggest that sulfur-deprived cells accumulate proteins with fewer sulfur-containing amino acids. Most of the sulfur deprivation responses are controlled by the SNRK2.1 protein kinase. The snrk2.1 mutant exhibits a set of unique responses during both sulfur-replete and sulfur-depleted conditions that are not observed in wild-type cells; the inability of this mutant to acclimate to S deprivation probably leads to elevated levels of singlet oxygen and severe oxidative stress, which ultimately causes cell death. The transcriptome results for wild-type and mutant cells strongly suggest the occurrence of massive changes in cellular physiology and metabolism as cells become depleted for sulfur and reveal aspects of acclimation that are likely critical for cell survival.
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Abstract
Reproductive altruism is an extreme form of altruism best typified by sterile castes in social insects and somatic cells in multicellular organisms. Although reproductive altruism is central to the evolution of multicellularity and eusociality, the mechanistic basis for the evolution of this behaviour is yet to be deciphered. Here, we report that the gene responsible for the permanent suppression of reproduction in the somatic cells of the multicellular green alga, Volvox carteri, evolved from a gene that in its unicellular relative, Chlamydomonas reinhardtii, is part of the general acclimation response to various environmental stress factors, which includes the temporary suppression of reproduction. Furthermore, we propose a model for the evolution of soma, in which by simulating the acclimation signal (i.e. a change in cellular redox status) in a developmental rather than environmental context, responses beneficial to a unicellular individual can be co-opted into an altruistic behaviour at the group level. The co-option of environmentally induced responses for reproductive altruism can contribute to the stability of this behaviour, as the loss of such responses would be costly for the individual. This hypothesis also predicts that temporally varying environments, which will select for more efficient acclimation responses, are likely to be more conducive to the evolution of reproductive altruism.
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Affiliation(s)
- Aurora M Nedelcu
- Department of Biology, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, Canada, E3B 5A3.
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Okazaki Y, Shimojima M, Sawada Y, Toyooka K, Narisawa T, Mochida K, Tanaka H, Matsuda F, Hirai A, Hirai MY, Ohta H, Saito K. A chloroplastic UDP-glucose pyrophosphorylase from Arabidopsis is the committed enzyme for the first step of sulfolipid biosynthesis. THE PLANT CELL 2009; 21:892-909. [PMID: 19286968 PMCID: PMC2671695 DOI: 10.1105/tpc.108.063925] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Plants synthesize a sulfur-containing lipid, sulfoquinovosyldiacylglycerol, which is one of three nonphosphorus glycerolipids that provide the bulk of the structural lipids in photosynthetic membranes. Here, the identification of a novel gene, UDP-glucose pyrophosphorylase3 (UGP3), required for sulfolipid biosynthesis is described. Transcriptome coexpression analysis demonstrated highly correlated expression of UGP3 with known genes for sulfolipid biosynthesis in Arabidopsis thaliana. Liquid chromatography-mass spectrometry analysis of leaf lipids in two Arabidopsis ugp3 mutants revealed that no sulfolipid was accumulated in these mutants, indicating the participation of UGP3 in sulfolipid biosynthesis. From the deduced amino acid sequence, UGP3 was presumed to be a UDP-glucose pyrophosphorylase (UGPase) involved in the generation of UDP-glucose, serving as the precursor of the polar head of sulfolipid. Recombinant UGP3 was able to catalyze the formation of UDP-glucose from glucose-1-phosphate and UTP. A transient assay using fluorescence fusion proteins and UGPase activity in isolated chloroplasts indicated chloroplastic localization of UGP3. The transcription level of UGP3 was increased by phosphate starvation. A comparative genomics study on UGP3 homologs across different plant species suggested the structural and functional conservation of the proteins and, thus, a committing role for UGP3 in sulfolipid synthesis.
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Affiliation(s)
- Yozo Okazaki
- RIKEN Plant Science Center, Tsurumi-ku, Yokohama 230-0045, Japan
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Moseley JL, Gonzalez-Ballester D, Pootakham W, Bailey S, Grossman AR. Genetic interactions between regulators of Chlamydomonas phosphorus and sulfur deprivation responses. Genetics 2009; 181:889-905. [PMID: 19087952 PMCID: PMC2651062 DOI: 10.1534/genetics.108.099382] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Accepted: 12/14/2008] [Indexed: 02/06/2023] Open
Abstract
The Chlamydomonas reinhardtii PSR1 gene is required for proper acclimation of the cells to phosphorus (P) deficiency. P-starved psr1 mutants show signs of secondary sulfur (S) starvation, exemplified by the synthesis of extracellular arylsulfatase and the accumulation of transcripts encoding proteins involved in S scavenging and assimilation. Epistasis analysis reveals that induction of the S-starvation responses in P-limited psr1 cells requires the regulatory protein kinase SNRK2.1, but bypasses the membrane-targeted activator, SAC1. The inhibitory kinase SNRK2.2 is necessary for repression of S-starvation responses during both nutrient-replete growth and P limitation; arylsulfatase activity and S deficiency-responsive genes are partially induced in the P-deficient snrk2.2 mutants and become fully activated in the P-deficient psr1snrk2.2 double mutant. During P starvation, the sac1snrk2.2 double mutants or the psr1sac1snrk2.2 triple mutants exhibit reduced arylsulfatase activity compared to snrk2.2 or psr1snrk2.2, respectively, but the sac1 mutation has little effect on the abundance of S deficiency-responsive transcripts in these strains, suggesting a post-transcriptional role for SAC1 in elicitation of S-starvation responses. Interestingly, P-starved psr1snrk2.2 cells bleach and die more rapidly than wild-type or psr1 strains, suggesting that activation of S-starvation responses during P deprivation is deleterious to the cell. From these results we infer that (i) P-deficient growth causes some internal S limitation, but the S-deficiency responses are normally inhibited during acclimation to P deprivation; (ii) the S-deficiency responses are not completely suppressed in P-deficient psr1 cells and consequently these cells synthesize some arylsulfatase and exhibit elevated levels of transcripts for S-deprivation genes; and (iii) this increased expression is controlled by regulators that modulate transcription of S-responsive genes during S-deprivation conditions. Overall, the work strongly suggests integration of the different circuits that control nutrient-deprivation responses in Chlamydomonas.
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Affiliation(s)
- Jeffrey L Moseley
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
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Gonzalez-Ballester D, Pollock SV, Pootakham W, Grossman AR. The central role of a SNRK2 kinase in sulfur deprivation responses. PLANT PHYSIOLOGY 2008; 147:216-27. [PMID: 18326790 PMCID: PMC2330293 DOI: 10.1104/pp.108.116137] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Accepted: 03/02/2008] [Indexed: 05/19/2023]
Abstract
In the absence of sulfur (S), Chlamydomonas reinhardtii increases the abundance of several transcripts encoding proteins associated with S acquisition and assimilation, conserves S amino acids, and acclimates to suboptimal growth conditions. A positive regulator, SAC1 (for sulfur acclimation protein 1), and a negative regulator, SAC3, were shown to participate in the control of these processes. In this study, we investigated two allelic mutants (ars11 and ars44) affected in a gene encoding a SNRK2 (for SNF1-related protein kinase 2) kinase designated SNRK2.1. Like the sac1 mutant, both snrk2.1 mutants were deficient in the expression of S-responsive genes. Furthermore, the mutant cells bleached more rapidly than wild-type cells during S deprivation, although the phenotypes of ars11 and ars44 were not identical: ars11 exhibited a more severe phenotype than either ars44 or sac1. The phenotypic differences between the ars11 and ars44 mutants reflected distinct alterations of SNRK2.1 mRNA splicing caused by insertion of the marker gene. The ars11 phenotype could be rescued by complementation with SNRK2.1 cDNA. In contrast to the nonepistatic relationship between SAC3 and SAC1, characterization of the sac3 ars11 double mutant showed that SNRK2.1 is epistatic to SAC3. These data reveal the crucial regulatory role of SNRK2.1 in the signaling cascade critical for eliciting S deprivation responses in Chlamydomonas. The phylogenetic relationships and structures of the eight members of the SNRK2 family in Chlamydomonas are discussed.
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Jeyasingh PD, Weider LJ. Fundamental links between genes and elements: evolutionary implications of ecological stoichiometry. Mol Ecol 2007; 16:4649-61. [PMID: 17944849 DOI: 10.1111/j.1365-294x.2007.03558.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Punidan D Jeyasingh
- Program in Ecology and Evolutionary Biology, Biological Station and Department of Zoology, University of Oklahoma, Norman, OK 73019, USA.
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Wilhelm C, Büchel C, Fisahn J, Goss R, Jakob T, Laroche J, Lavaud J, Lohr M, Riebesell U, Stehfest K, Valentin K, Kroth PG. The regulation of carbon and nutrient assimilation in diatoms is significantly different from green algae. Protist 2006; 157:91-124. [PMID: 16621693 DOI: 10.1016/j.protis.2006.02.003] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Christian Wilhelm
- Department of Plant Physiology, Institute of Biology I, University of Leipzig, Johannisallee 23, 04103 Leipzig, Germany.
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