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Liu F, Li J, Jin S, Liu L. Molecular diversity and seasonal dynamics of Ostreococcus (Mamiellophyceae, Chlorophyta) in typical mariculture bays based on metabarcoding analysis. MARINE ENVIRONMENTAL RESEARCH 2024; 202:106764. [PMID: 39332317 DOI: 10.1016/j.marenvres.2024.106764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2024] [Revised: 08/30/2024] [Accepted: 09/20/2024] [Indexed: 09/29/2024]
Abstract
Ostreococcus (Mamiellophyceae, Chlorophyta) is a cosmopolitan genus of marine pico-phytoplankton and the smallest free-living photosynthetic eukaryotes with cell size of 1-2 μm. To understand the diversity and spatio-temporal distribution of Ostreococcus in the Rongcheng coastal regions in northern China, metabarcoding analysis based on the 18S rDNA V4 molecular marker was applied to study the molecular diversity and seasonal dynamics of Ostreococcus in three typical mariculture bays (Rongcheng Bay, Lidao Bay and Sanggou Bay). A total of 103 amplicon sequence variants (ASVs) annotated as Ostreococcus were detected in these three typical mariculture bays throughout the year. The top five ASVs in terms of abundance were ASV4, ASV9, ASV14, ASV28 and ASV109, totally occupying 99.1% of Ostreococcus reads. Phylogenetic analysis showed that these five dominant ASVs represented two Ostreococcus ecotypes (OI and OII) and were grouped into four Ostreococcus clades including Ostreococcus lucimarinus (ASV9) and Ostreococcus tauri (ASV28 and ASV109) in OI, and Ostreococcus sp. RC1 (ASV4) and Ostreococcus sp. RC2 (ASV14) in OII, which provided direct evidence to support the co-existence of two ecotypes in the Rongcheng coastal regions. Five dominant ASVs in OI and OII exhibited two distinct seasonal distribution patterns. Three dominant ASVs (ASV9, ASV28 and ASV109) in OI could be detected in all four seasons of the year, exhibiting native distribution properties, while two ASVs (ASV4 and ASV14) in OII decreased sharply in winter and could not be detected in spring, exhibiting characteristics of alien inputs. The composition, succession and association of Ostreococcus community were mainly driven by water temperature in these mariculture bays. This study helps us systematically understand the molecular diversity and distribution patterns of Ostreococcus in typical mariculture bays in northern China, laying the foundation for understanding and revealing the ecological functions of pico-phytoplankton.
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Affiliation(s)
- Feng Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, 266000, PR China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, Shandong, 266237, PR China; College of Marine Science, University of Chinese Academy of Sciences, Beijing 101408, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, 266000, PR China.
| | - Jiamin Li
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, 266000, PR China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, Shandong, 266237, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, 266000, PR China
| | - Shuangle Jin
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, 266000, PR China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, Shandong, 266237, PR China; College of Marine Science, University of Chinese Academy of Sciences, Beijing 101408, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, 266000, PR China
| | - Liang Liu
- Rongcheng Ocean and Fishery Monitoring and Disaster Mitigation Center, Rongcheng, Shandong, 264300, PR China
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de Barros Dantas LL, Eldridge BM, Dorling J, Dekeya R, Lynch DA, Dodd AN. Circadian regulation of metabolism across photosynthetic organisms. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:650-668. [PMID: 37531328 PMCID: PMC10953457 DOI: 10.1111/tpj.16405] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/15/2023] [Accepted: 07/18/2023] [Indexed: 08/04/2023]
Abstract
Circadian regulation produces a biological measure of time within cells. The daily cycle in the availability of light for photosynthesis causes dramatic changes in biochemical processes in photosynthetic organisms, with the circadian clock having crucial roles in adaptation to these fluctuating conditions. Correct alignment between the circadian clock and environmental day-night cycles maximizes plant productivity through its regulation of metabolism. Therefore, the processes that integrate circadian regulation with metabolism are key to understanding how the circadian clock contributes to plant productivity. This forms an important part of exploiting knowledge of circadian regulation to enhance sustainable crop production. Here, we examine the roles of circadian regulation in metabolic processes in source and sink organ structures of Arabidopsis. We also evaluate possible roles for circadian regulation in root exudation processes that deposit carbon into the soil, and the nature of the rhythmic interactions between plants and their associated microbial communities. Finally, we examine shared and differing aspects of the circadian regulation of metabolism between Arabidopsis and other model photosynthetic organisms, and between circadian control of metabolism in photosynthetic and non-photosynthetic organisms. This synthesis identifies a variety of future research topics, including a focus on metabolic processes that underlie biotic interactions within ecosystems.
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Affiliation(s)
| | - Bethany M. Eldridge
- Department of Cell and Developmental BiologyJohn Innes Centre, Norwich Research ParkNorwichUK
| | - Jack Dorling
- Department of Cell and Developmental BiologyJohn Innes Centre, Norwich Research ParkNorwichUK
| | - Richard Dekeya
- Department of Cell and Developmental BiologyJohn Innes Centre, Norwich Research ParkNorwichUK
| | - Deirdre A. Lynch
- Department of Cell and Developmental BiologyJohn Innes Centre, Norwich Research ParkNorwichUK
| | - Antony N. Dodd
- Department of Cell and Developmental BiologyJohn Innes Centre, Norwich Research ParkNorwichUK
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Petersen J, Rredhi A, Szyttenholm J, Mittag M. Evolution of circadian clocks along the green lineage. PLANT PHYSIOLOGY 2022; 190:924-937. [PMID: 35325228 PMCID: PMC9516769 DOI: 10.1093/plphys/kiac141] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 03/04/2022] [Indexed: 05/10/2023]
Abstract
Circadian clocks govern temporal programs in the green lineage (Chloroplastida) as they do in other photosynthetic pro- and eukaryotes, bacteria, fungi, animals, and humans. Their physiological properties, including entrainment, phase responses, and temperature compensation, are well conserved. The involvement of transcriptional/translational feedback loops in the oscillatory machinery and reversible phosphorylation events are also maintained. Circadian clocks control a large variety of output rhythms in green algae and terrestrial plants, adjusting their metabolism and behavior to the day-night cycle. The angiosperm Arabidopsis (Arabidopsis thaliana) represents a well-studied circadian clock model. Several molecular components of its oscillatory machinery are conserved in other Chloroplastida, but their functions may differ. Conserved clock components include at least one member of the CIRCADIAN CLOCK ASSOCIATED1/REVEILLE and one of the PSEUDO RESPONSE REGULATOR family. The Arabidopsis evening complex members EARLY FLOWERING3 (ELF3), ELF4, and LUX ARRHYTHMO are found in the moss Physcomitrium patens and in the liverwort Marchantia polymorpha. In the flagellate chlorophyte alga Chlamydomonas reinhardtii, only homologs of ELF4 and LUX (named RHYTHM OF CHLOROPLAST ROC75) are present. Temporal ROC75 expression in C. reinhardtii is opposite to that of the angiosperm LUX, suggesting different clock mechanisms. In the picoalga Ostreococcus tauri, both ELF genes are missing, suggesting that it has a progenitor circadian "green" clock. Clock-relevant photoreceptors and thermosensors vary within the green lineage, except for the CRYPTOCHROMEs, whose variety and functions may differ. More genetically tractable models of Chloroplastida are needed to draw final conclusions about the gradual evolution of circadian clocks within the green lineage.
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Affiliation(s)
- Jan Petersen
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena 07743, Germany
| | - Anxhela Rredhi
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena 07743, Germany
| | - Julie Szyttenholm
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena 07743, Germany
| | - Maria Mittag
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena 07743, Germany
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Jespersen N, Monrroy L, Barandun J. Impact of Genome Reduction in Microsporidia. EXPERIENTIA SUPPLEMENTUM (2012) 2022; 114:1-42. [PMID: 35543997 DOI: 10.1007/978-3-030-93306-7_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Microsporidia represent an evolutionary outlier in the tree of life and occupy the extreme edge of the eukaryotic domain with some of their biological features. Many of these unicellular fungi-like organisms have reduced their genomic content to potentially the lowest limit. With some of the most compacted eukaryotic genomes, microsporidia are excellent model organisms to study reductive evolution and its functional consequences. While the growing number of sequenced microsporidian genomes have elucidated genome composition and organization, a recent increase in complementary post-genomic studies has started to shed light on the impacts of genome reduction in these unique pathogens. This chapter will discuss the biological framework enabling genome minimization and will use one of the most ancient and essential macromolecular complexes, the ribosome, to illustrate the effects of extreme genome reduction on a structural, molecular, and cellular level. We outline how reductive evolution in microsporidia has shaped DNA organization, the composition and function of the ribosome, and the complexity of the ribosome biogenesis process. Studying compacted mechanisms, processes, or macromolecular machines in microsporidia illuminates their unique lifestyle and provides valuable insights for comparative eukaryotic structural biology.
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Affiliation(s)
- Nathan Jespersen
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Science for Life Laboratory, Umeå University, Umeå, Sweden.
| | - Leonardo Monrroy
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Jonas Barandun
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Science for Life Laboratory, Umeå University, Umeå, Sweden.
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Carrasco Flores D, Fricke M, Wesp V, Desirò D, Kniewasser A, Hölzer M, Marz M, Mittag M. A marine Chlamydomonas sp. emerging as an algal model. JOURNAL OF PHYCOLOGY 2021; 57:54-69. [PMID: 33043442 DOI: 10.1111/jpy.13083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
The freshwater microalga Chlamydomonas reinhardtii, which lives in wet soil, has served for decades as a model for numerous biological processes, and many tools have been introduced for this organism. Here, we have established a stable nuclear transformation for its marine counterpart, Chlamydomonas sp. SAG25.89, by fusing specific cis-acting elements from its Actin gene with the gene providing hygromycin resistance and using an elaborated electroporation protocol. Like C. reinhardtii, Chlamydomonas sp. has a high GC content, allowing reporter genes and selection markers to be applicable in both organisms. Chlamydomonas sp. grows purely photoautotrophically and requires ammonia as a nitrogen source because its nuclear genome lacks some of the genes required for nitrogen metabolism. Interestingly, it can grow well under both low and very high salinities (up to 50 g · L-1 ) rendering it as a model for osmotolerance. We further show that Chlamydomonas sp. grows well from 15 to 28°C, but halts its growth at 32°C. The genome of Chlamydomonas sp. contains some gene homologs the expression of which is regulated according to the ambient temperatures and/or confer thermal acclimation in C. reinhardtii. Thus, knowledge of temperature acclimation can now be compared to the marine species. Furthermore, Chlamydomonas sp. can serve as a model for studying marine microbial interactions and for comparing mechanisms in freshwater and marine environments. Chlamydomonas sp. was previously shown to be immobilized rapidly by a cyclic lipopeptide secreted from the antagonistic bacterium Pseudomonas protegens PF-5, which deflagellates C. reinhardtii.
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Affiliation(s)
- David Carrasco Flores
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, Jena, 07743, Germany
| | - Markus Fricke
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, Jena, 07743, Germany
| | - Valentin Wesp
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, Jena, 07743, Germany
| | - Daniel Desirò
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, Jena, 07743, Germany
| | - Anja Kniewasser
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, Jena, 07743, Germany
| | - Martin Hölzer
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, Jena, 07743, Germany
| | - Manja Marz
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, Jena, 07743, Germany
- FLI, Leibniz Institute for Age Research, Beutenbergstr. 11, Jena, 07745, Germany
| | - Maria Mittag
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, Jena, 07743, Germany
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Hu YOO, Karlson B, Charvet S, Andersson AF. Diversity of Pico- to Mesoplankton along the 2000 km Salinity Gradient of the Baltic Sea. Front Microbiol 2016; 7:679. [PMID: 27242706 PMCID: PMC4864665 DOI: 10.3389/fmicb.2016.00679] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/26/2016] [Indexed: 01/12/2023] Open
Abstract
Microbial plankton form the productive base of both marine and freshwater ecosystems and are key drivers of global biogeochemical cycles of carbon and nutrients. Plankton diversity is immense with representations from all major phyla within the three domains of life. So far, plankton monitoring has mainly been based on microscopic identification, which has limited sensitivity and reproducibility, not least because of the numerical majority of plankton being unidentifiable under the light microscope. High-throughput sequencing of taxonomic marker genes offers a means to identify taxa inaccessible by traditional methods; thus, recent studies have unveiled an extensive previously unknown diversity of plankton. Here, we conducted ultra-deep Illumina sequencing (average 105 sequences/sample) of rRNA gene amplicons of surface water eukaryotic and bacterial plankton communities sampled in summer along a 2000 km transect following the salinity gradient of the Baltic Sea. Community composition was strongly correlated with salinity for both bacterial and eukaryotic plankton assemblages, highlighting the importance of salinity for structuring the biodiversity within this ecosystem. In contrast, no clear trends in alpha-diversity for bacterial or eukaryotic communities could be detected along the transect. The distribution of major planktonic taxa followed expected patterns as observed in monitoring programs, but groups novel to the Baltic Sea were also identified, such as relatives to the coccolithophore Emiliana huxleyi detected in the northern Baltic Sea. This study provides the first ultra-deep sequencing-based survey on eukaryotic and bacterial plankton biogeography in the Baltic Sea.
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Affiliation(s)
- Yue O O Hu
- Science for Life Laboratory, Division of Gene Technology, School of Biotechnology, KTH Royal Institute of Technology Stockholm, Sweden
| | - Bengt Karlson
- Oceanography, Research & Development, Swedish Meteorological and Hydrological Institute Gothenburg, Sweden
| | - Sophie Charvet
- Leibniz Institute for Baltic Sea Research Warnemünde Rostock, Germany
| | - Anders F Andersson
- Science for Life Laboratory, Division of Gene Technology, School of Biotechnology, KTH Royal Institute of Technology Stockholm, Sweden
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Hu YOO, Karlson B, Charvet S, Andersson AF. Diversity of Pico- to Mesoplankton along the 2000 km Salinity Gradient of the Baltic Sea. Front Microbiol 2016; 7:679. [PMID: 27242706 DOI: 10.3389/fmicb.2016.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/26/2016] [Indexed: 05/22/2023] Open
Abstract
Microbial plankton form the productive base of both marine and freshwater ecosystems and are key drivers of global biogeochemical cycles of carbon and nutrients. Plankton diversity is immense with representations from all major phyla within the three domains of life. So far, plankton monitoring has mainly been based on microscopic identification, which has limited sensitivity and reproducibility, not least because of the numerical majority of plankton being unidentifiable under the light microscope. High-throughput sequencing of taxonomic marker genes offers a means to identify taxa inaccessible by traditional methods; thus, recent studies have unveiled an extensive previously unknown diversity of plankton. Here, we conducted ultra-deep Illumina sequencing (average 10(5) sequences/sample) of rRNA gene amplicons of surface water eukaryotic and bacterial plankton communities sampled in summer along a 2000 km transect following the salinity gradient of the Baltic Sea. Community composition was strongly correlated with salinity for both bacterial and eukaryotic plankton assemblages, highlighting the importance of salinity for structuring the biodiversity within this ecosystem. In contrast, no clear trends in alpha-diversity for bacterial or eukaryotic communities could be detected along the transect. The distribution of major planktonic taxa followed expected patterns as observed in monitoring programs, but groups novel to the Baltic Sea were also identified, such as relatives to the coccolithophore Emiliana huxleyi detected in the northern Baltic Sea. This study provides the first ultra-deep sequencing-based survey on eukaryotic and bacterial plankton biogeography in the Baltic Sea.
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Affiliation(s)
- Yue O O Hu
- Science for Life Laboratory, Division of Gene Technology, School of Biotechnology, KTH Royal Institute of Technology Stockholm, Sweden
| | - Bengt Karlson
- Oceanography, Research & Development, Swedish Meteorological and Hydrological Institute Gothenburg, Sweden
| | - Sophie Charvet
- Leibniz Institute for Baltic Sea Research Warnemünde Rostock, Germany
| | - Anders F Andersson
- Science for Life Laboratory, Division of Gene Technology, School of Biotechnology, KTH Royal Institute of Technology Stockholm, Sweden
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Gao Y, Li MY, Zhao J, Zhang YC, Xie QJ, Chen DH. Genome-wide analysis of RING finger proteins in the smallest free-living photosynthetic eukaryote Ostreococus tauri. Mar Genomics 2015; 26:51-61. [PMID: 26751716 DOI: 10.1016/j.margen.2015.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 11/19/2022]
Abstract
RING finger proteins and ubiquitination marks are widely involved in diverse aspects of growth and development, biological processes, and stress or environmental responses. As the smallest free-living photosynthetic eukaryote known so far, the green alga Ostreococus tauri has become an excellent model for investigating the origin of different gene families in the green lineage. Here, 65 RING domains in 65 predicted proteins were identified from O. tauri and on the basis of one or more substitutions at the metal ligand positions and spacing between them they were divided into eight canonical or modified types (RING-CH, -H2, -v, -C2, -C3HCHC2, -C2HC5, -C3GC3S, and -C2SHC4), in which the latter four were newly identified and might represent the intermediate states between RING domain and other similar domains, respectively. RING finger proteins were classified into eight classes based on the presence of additional domains, including RING-Only, -Plus, -C3H1, -PHD, -WD40, -PEX, -TM, and -DEXDc classes. These RING family genes usually lack introns and are distributed over 17 chromosomes. In addition, 29 RING-finger proteins in O. tauri share different degrees of homology with those in the model flowering plant Arabidopsis, indicating they might be necessary for the basic survival of free-living eukaryotes. Therefore, our results provide new insight into the general classification and evolutionary conservation of RING domain-containing proteins in O. tauri.
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Affiliation(s)
- Yan Gao
- Key Laboratory of Education Department of Hunan Province on Plant Genetics and Molecular Biology, Hunan Agricultural University, Changsha 410128, China
| | - Ming-Yi Li
- Key Laboratory of Education Department of Hunan Province on Plant Genetics and Molecular Biology, Hunan Agricultural University, Changsha 410128, China
| | - Jing Zhao
- Key Laboratory of Education Department of Hunan Province on Plant Genetics and Molecular Biology, Hunan Agricultural University, Changsha 410128, China
| | - Yan-Cui Zhang
- Key Laboratory of Education Department of Hunan Province on Plant Genetics and Molecular Biology, Hunan Agricultural University, Changsha 410128, China
| | - Qiu-Jiao Xie
- Key Laboratory of Education Department of Hunan Province on Plant Genetics and Molecular Biology, Hunan Agricultural University, Changsha 410128, China
| | - Dong-Hong Chen
- Key Laboratory of Education Department of Hunan Province on Plant Genetics and Molecular Biology, Hunan Agricultural University, Changsha 410128, China; College of Bioscience and Biotechnology, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Hunan Agricultural University, Changsha 410128, China.
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Verhelst B, Van de Peer Y, Rouzé P. The complex intron landscape and massive intron invasion in a picoeukaryote provides insights into intron evolution. Genome Biol Evol 2014; 5:2393-401. [PMID: 24273312 PMCID: PMC3879977 DOI: 10.1093/gbe/evt189] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Genes in pieces and spliceosomal introns are a landmark of eukaryotes, with intron invasion usually assumed to have happened early on in evolution. Here, we analyze the intron landscape of Micromonas, a unicellular green alga in the Mamiellophyceae lineage, demonstrating the coexistence of several classes of introns and the occurrence of recent massive intron invasion. This study focuses on two strains, CCMP1545 and RCC299, and their related individuals from ocean samplings, showing that they not only harbor different classes of introns depending on their location in the genome, as for other Mamiellophyceae, but also uniquely carry several classes of repeat introns. These introns, dubbed introner elements (IEs), are found at novel positions in genes and have conserved sequences, contrary to canonical introns. This IE invasion has a huge impact on the genome, doubling the number of introns in the CCMP1545 strain. We hypothesize that each IE class originated from a single ancestral IE that has been colonizing the genome after strain divergence by inserting copies of itself into genes by intron transposition, likely involving reverse splicing. Along with similar cases recently observed in other organisms, our observations in Micromonas strains shed a new light on the evolution of introns, suggesting that intron gain is more widespread than previously thought.
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Affiliation(s)
- Bram Verhelst
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Belgium
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Shotgun proteomic analysis of the unicellular alga Ostreococcus tauri. J Proteomics 2011; 74:2060-70. [DOI: 10.1016/j.jprot.2011.05.028] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 05/03/2011] [Accepted: 05/17/2011] [Indexed: 01/02/2023]
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Veetil SK, Mittal C, Ranjan P, Kateriya S. A conserved isoleucine in the LOV1 domain of a novel phototropin from the marine alga Ostreococcus tauri modulates the dark state recovery of the domain. Biochim Biophys Acta Gen Subj 2011; 1810:675-82. [PMID: 21554927 DOI: 10.1016/j.bbagen.2011.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 04/15/2011] [Accepted: 04/18/2011] [Indexed: 10/18/2022]
Abstract
BACKGROUND Phototropins are UV-A/blue light receptor proteins with two LOV (Light-Oxygen-Voltage) sensor domains at their N terminus and a kinase domain at the C-terminus in photoautotrophic organisms. This is the first research report of a canonical phototropin from marine algae Ostreococcus tauri. METHODS We synthesized core LOV1 (OtLOV1) domain-encoding portion of the phototropin gene of O. tauri, the domain was heterologously expressed, purified and assessed for its spectral properties and dark recovery kinetics by UV-Visible, fluorescence spectroscopy and mutational studies. Quaternary structure characteristics were studied by SEC and glutaraldehyde crosslinking. RESULTS The absorption spectrum of OtLOV1 lacks the characteristic 361nm peak shown by other LOV1 domains. It undergoes a photocycle with a dark state recovery time of approximately 30min (τ=300.35s). Native OtLOV1 stayed as dimer in aqueous solution and the dimer formation was light and concentration independent. Mutating isoleucine at 43rd position to valine accelerated the dark recovery time by more than 10-fold. Mutating it to serine reduced sensitivity to blue light, but the dark recovery time remained unaltered. I43S mutation also destabilized the FMN binding to a great extent. CONCLUSION The OtLOV1 domain of the newly identified OtPhot is functional and the isoleucine at position 43 of OtLOV1 is the key residue responsible for fine-tuning the domain properties. GENERAL SIGNIFICANCE This is the first characterized LOV1 domain of a canonical phototropin from a marine alga and spectral properties of the domain are similar to that of the LOV1 domain of higher plants.
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Affiliation(s)
- Sindhu Kandoth Veetil
- Department of Biochemistry, University of Delhi South Campus, Benito Juares Road, New Delhi-110021, India
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Kaczmarzyk D, Fulda M. Fatty acid activation in cyanobacteria mediated by acyl-acyl carrier protein synthetase enables fatty acid recycling. PLANT PHYSIOLOGY 2010; 152:1598-610. [PMID: 20061450 PMCID: PMC2832271 DOI: 10.1104/pp.109.148007] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 12/30/2009] [Indexed: 05/21/2023]
Abstract
In cyanobacteria fatty acids destined for lipid synthesis can be synthesized de novo, but also exogenous free fatty acids from the culture medium can be directly incorporated into lipids. Activation of exogenous fatty acids is likely required prior to their utilization. To identify the enzymatic activity responsible for activation we cloned candidate genes from Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 and identified the encoded proteins as acyl-acyl carrier protein synthetases (Aas). The enzymes catalyze the ATP-dependent esterification of fatty acids to the thiol of acyl carrier protein. The two protein sequences are only distantly related to known prokaryotic Aas proteins but they display strong similarity to sequences that can be found in almost all organisms that perform oxygenic photosynthesis. To investigate the biological role of Aas activity in cyanobacteria, aas knockout mutants were generated in the background of Synechocystis sp. PCC 6803 and S. elongatus PCC 7942. The mutant strains showed two phenotypes characterized by the inability to utilize exogenous fatty acids and by the secretion of endogenous fatty acids into the culture medium. The analyses of extracellular and intracellular fatty acid profiles of aas mutant strains as well as labeling experiments indicated that the detected free fatty acids are released from membrane lipids. The data suggest a considerable turnover of lipid molecules and a role for Aas activity in recycling the released fatty acids. In this model, lipid degradation represents a third supply of fatty acids for lipid synthesis in cyanobacteria.
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14
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Affiliation(s)
- John M Archibald
- Canadian Institute for Advanced Research, Program in Integrated Microbial Biodiversity, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada.
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Lanier W, Moustafa A, Bhattacharya D, Comeron JM. EST analysis of Ostreococcus lucimarinus, the most compact eukaryotic genome, shows an excess of introns in highly expressed genes. PLoS One 2008; 3:e2171. [PMID: 18478122 PMCID: PMC2367439 DOI: 10.1371/journal.pone.0002171] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Accepted: 03/25/2008] [Indexed: 11/19/2022] Open
Abstract
Background The genome of the pico-eukaryotic (bacterial-sized) prasinophyte green alga Ostreococcus lucimarinus has one of the highest gene densities known in eukaryotes, yet it contains many introns. Phylogenetic studies suggest this unusually compact genome (13.2 Mb) is an evolutionarily derived state among prasinophytes. The presence of introns in the highly reduced O. lucimarinus genome appears to be in opposition to simple explanations of genome evolution based on unidirectional tendencies, either neutral or selective. Therefore, patterns of intron retention in this species can potentially provide insights into the forces governing intron evolution. Methodology/Principal Findings Here we studied intron features and levels of expression in O. lucimarinus using expressed sequence tags (ESTs) to annotate the current genome assembly. ESTs were assembled into unigene clusters that were mapped back to the O. lucimarinus Build 2.0 assembly using BLAST and the level of gene expression was inferred from the number of ESTs in each cluster. We find a positive correlation between expression levels and both intron number (R = +0.0893, p = <0.0005) and intron density (number of introns/kb of CDS; R = +0.0753, p = <0.005). Conclusions/Significance In a species with a genome that has been recently subjected to a great reduction of non-coding DNA, these results imply the existence of selective/functional roles for introns that are principally detectable in highly expressed genes. In these cases, introns are likely maintained by balancing the selective forces favoring their maintenance with other mutational and/or selective forces acting on genome size.
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Affiliation(s)
- William Lanier
- Interdisciplinary Program in Genetics, University of Iowa, Iowa, United States of America
| | - Ahmed Moustafa
- Interdisciplinary Program in Genetics, University of Iowa, Iowa, United States of America
| | - Debashish Bhattacharya
- Interdisciplinary Program in Genetics, University of Iowa, Iowa, United States of America
- Department of Biological Sciences and Roy J. Carver Center for Comparative Genomics, University of Iowa, Iowa, United States of America
| | - Josep M. Comeron
- Interdisciplinary Program in Genetics, University of Iowa, Iowa, United States of America
- Department of Biological Sciences and Roy J. Carver Center for Comparative Genomics, University of Iowa, Iowa, United States of America
- * E-mail:
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