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Peter EK, Jaeger C, Lisec J, Peters RS, Mourot R, Rossel PE, Tranter M, Anesio AM, Benning LG. Endometabolic profiling of pigmented glacier ice algae: the impact of sample processing. Metabolomics 2024; 20:98. [PMID: 39123092 PMCID: PMC11315761 DOI: 10.1007/s11306-024-02147-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 06/24/2024] [Indexed: 08/12/2024]
Abstract
INTRODUCTION Glacier ice algae, mainly Ancylonema alaskanum and Ancylonema nordenskiöldi, bloom on Greenland Ice Sheet bare ice surfaces. They significantly decrease surface albedo due to their purple-brown pigmentation, thus increasing melt. Little is known about their metabolic adaptation and factors controlling algal growth dynamics and pigment formation. A challenge in obtaining such data is the necessity of melting samples, which delays preservation and introduces bias to metabolomic analysis. There is a need to evaluate the physiological response of algae to melting and establish consistent sample processing strategies for metabolomics of ice microbial communities. OBJECTIVES To address the impact of sample melting procedure on metabolic characterization and establish a processing and analytical workflow for endometabolic profiling of glacier ice algae. METHODS We employed untargeted, high-resolution mass spectrometry and tested the effect of sample melt temperature (10, 15, 20 °C) and processing delay (up to 49 h) on the metabolome and lipidome, and complemented this approach with cell counts (FlowCam), photophysiological analysis (PAM) and diversity characterization. RESULTS AND CONCLUSION We putatively identified 804 metabolites, with glycerolipids, glycerophospholipids and fatty acyls being the most prominent superclasses (> 50% of identified metabolites). Among the polar metabolome, carbohydrates and amino acid-derivatives were the most abundant. We show that 8% of the metabolome is affected by melt duration, with a pronounced decrease in betaine membrane lipids and pigment precursors, and an increase in phospholipids. Controlled fast melting at 10 °C resulted in the highest consistency, and is our recommendation for future supraglacial metabolomics studies.
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Affiliation(s)
- Elisa K Peter
- German Research Centre for Geosciences - GFZ, 14473, Potsdam, Germany.
- Department of Earth Sciences, Freie Universität Berlin, 12249, Berlin, Germany.
| | - Carsten Jaeger
- Bundesanstalt für Materialforschung und -prüfung (BAM), 12489, Berlin, Germany
| | - Jan Lisec
- Bundesanstalt für Materialforschung und -prüfung (BAM), 12489, Berlin, Germany
| | - R Sven Peters
- German Research Centre for Geosciences - GFZ, 14473, Potsdam, Germany
| | - Rey Mourot
- German Research Centre for Geosciences - GFZ, 14473, Potsdam, Germany
- Department of Earth Sciences, Freie Universität Berlin, 12249, Berlin, Germany
| | - Pamela E Rossel
- German Research Centre for Geosciences - GFZ, 14473, Potsdam, Germany
| | - Martyn Tranter
- Department of Environmental Science, Aarhus University, 4000, Roskilde, Denmark
| | - Alexandre M Anesio
- Department of Environmental Science, Aarhus University, 4000, Roskilde, Denmark
| | - Liane G Benning
- German Research Centre for Geosciences - GFZ, 14473, Potsdam, Germany.
- Department of Earth Sciences, Freie Universität Berlin, 12249, Berlin, Germany.
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2
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Dhabalia Ashok A, de Vries S, Darienko T, Irisarri I, de Vries J. Evolutionary assembly of the plant terrestrialization toolkit from protein domains. Proc Biol Sci 2024; 291:20240985. [PMID: 39081174 PMCID: PMC11289646 DOI: 10.1098/rspb.2024.0985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 06/26/2024] [Accepted: 06/27/2024] [Indexed: 08/02/2024] Open
Abstract
Land plants (embryophytes) came about in a momentous evolutionary singularity: plant terrestrialization. This event marks not only the conquest of land by plants but also the massive radiation of embryophytes into a diverse array of novel forms and functions. The unique suite of traits present in the earliest land plants is thought to have been ushered in by a burst in genomic novelty. Here, we asked the question of how these bursts were possible. For this, we explored: (i) the initial emergence and (ii) the reshuffling of domains to give rise to hallmark environmental response genes of land plants. We pinpoint that a quarter of the embryophytic genes for stress physiology are specific to the lineage, yet a significant portion of this novelty arises not de novo but from reshuffling and recombining of pre-existing domains. Our data suggest that novel combinations of old genomic substrate shaped the plant terrestrialization toolkit, including hallmark processes in signalling, biotic interactions and specialized metabolism.
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Affiliation(s)
- Amra Dhabalia Ashok
- Department of Applied Bioinformatics, University of Goettingen, Institute for Microbiology and Genetics, Goldschmidtstr. 1, Goettingen37077, Germany
| | - Sophie de Vries
- Department of Applied Bioinformatics, University of Goettingen, Institute for Microbiology and Genetics, Goldschmidtstr. 1, Goettingen37077, Germany
| | - Tatyana Darienko
- Department of Applied Bioinformatics, University of Goettingen, Institute for Microbiology and Genetics, Goldschmidtstr. 1, Goettingen37077, Germany
| | - Iker Irisarri
- Department of Applied Bioinformatics, University of Goettingen, Institute for Microbiology and Genetics, Goldschmidtstr. 1, Goettingen37077, Germany
- University of Goettingen, Campus Institute Data Science (CIDAS), Goldschmidstr. 1, Goettingen37077, Germany
- Section Phylogenomics, Centre for Molecular biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change (LIB), Museum of Nature Hamburg, Martin-Luther-King-Platz 3, Hamburg20146, Germany
| | - Jan de Vries
- Department of Applied Bioinformatics, University of Goettingen, Institute for Microbiology and Genetics, Goldschmidtstr. 1, Goettingen37077, Germany
- University of Goettingen, Campus Institute Data Science (CIDAS), Goldschmidstr. 1, Goettingen37077, Germany
- Department of Applied Bioinformatics, University of Goettingen, Goettingen Center for Molecular Biosciences (GZMB), Goldschmidtstr. 1, Goettingen37077, Germany
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3
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Busch A, Gerbracht JV, Davies K, Hoecker U, Hess S. Comparative transcriptomics elucidates the cellular responses of an aeroterrestrial zygnematophyte to UV radiation. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3624-3642. [PMID: 38520340 PMCID: PMC11156808 DOI: 10.1093/jxb/erae131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/22/2024] [Indexed: 03/25/2024]
Abstract
The zygnematophytes are the closest relatives of land plants and comprise several lineages that adapted to a life on land. Species of the genus Serritaenia form colorful, mucilaginous capsules, which surround the cells and block harmful solar radiation, one of the major terrestrial stressors. In eukaryotic algae, this 'sunscreen mucilage' represents a unique photoprotective strategy, whose induction and chemical background are unknown. We generated a de novo transcriptome of Serritaenia testaceovaginata and studied its gene regulation under moderate UV radiation (UVR) that triggers sunscreen mucilage under experimental conditions. UVR induced the repair of DNA and the photosynthetic apparatus as well as the synthesis of aromatic specialized metabolites. Specifically, we observed pronounced expressional changes in the production of aromatic amino acids, phenylpropanoid biosynthesis genes, potential cross-membrane transporters of phenolics, and extracellular, oxidative enzymes. Interestingly, the most up-regulated enzyme was a secreted class III peroxidase, whose embryophyte homologs are involved in apoplastic lignin formation. Overall, our findings reveal a conserved, plant-like UVR perception system (UVR8 and downstream factors) in zygnematophyte algae and point to a polyphenolic origin of the sunscreen pigment of Serritaenia, whose synthesis might be extracellular and oxidative, resembling that of plant lignins.
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Affiliation(s)
- Anna Busch
- Department of Biology, University of Cologne, Zülpicher Str. 47b, D-50674 Cologne, Germany
| | - Jennifer V Gerbracht
- Department of Biology, University of Cologne, Zülpicher Str. 47b, D-50674 Cologne, Germany
| | - Kevin Davies
- The New Zealand Institute for Plant and Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - Ute Hoecker
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Zülpicher Strasse 47b, D-50674, Cologne, Germany
| | - Sebastian Hess
- Department of Biology, University of Cologne, Zülpicher Str. 47b, D-50674 Cologne, Germany
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4
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Bowles AMC, Williams TA, Donoghue PCJ, Campbell DA, Williamson CJ. Metagenome-assembled genome of the glacier alga Ancylonema yields insights into the evolution of streptophyte life on ice and land. THE NEW PHYTOLOGIST 2024. [PMID: 38840553 DOI: 10.1111/nph.19860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/03/2024] [Indexed: 06/07/2024]
Abstract
Contemporary glaciers are inhabited by streptophyte algae that balance photosynthesis and growth with tolerance of low temperature, desiccation and UV radiation. These same environmental challenges have been hypothesised as the driving force behind the evolution of land plants from streptophyte algal ancestors in the Cryogenian (720-635 million years ago). We sequenced, assembled and analysed the metagenome-assembled genome of the glacier alga Ancylonema nordenskiöldii to investigate its adaptations to life in ice, and whether this represents a vestige of Cryogenian exaptations. Phylogenetic analysis confirms the placement of glacier algae within the sister lineage to land plants, Zygnematophyceae. The metagenome-assembled genome is characterised by an expansion of genes involved in tolerance of high irradiance and UV light, while lineage-specific diversification is linked to the novel screening pigmentation of glacier algae. We found no support for the hypothesis of a common genomic basis for adaptations to ice and to land in streptophytes. Comparative genomics revealed that the reductive morphological evolution in the ancestor of Zygnematophyceae was accompanied by reductive genome evolution. This first genome-scale data for glacier algae suggests an Ancylonema-specific adaptation to the cryosphere, and sheds light on the genome evolution of land plants and Zygnematophyceae.
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Affiliation(s)
- Alexander M C Bowles
- School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UK
- Bristol Palaeobiology Group, School of Biological Sciences and School of Earth Sciences, Life Sciences Building, University of Bristol, Bristol, BS8 1TQ, UK
| | - Tom A Williams
- Bristol Palaeobiology Group, School of Biological Sciences and School of Earth Sciences, Life Sciences Building, University of Bristol, Bristol, BS8 1TQ, UK
| | - Philip C J Donoghue
- Bristol Palaeobiology Group, School of Biological Sciences and School of Earth Sciences, Life Sciences Building, University of Bristol, Bristol, BS8 1TQ, UK
| | - Douglas A Campbell
- Department of Biology, Mount Allison University, Sackville, NB, E4L 1H3, Canada
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5
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Procházková L, Remias D, Nedbalová L, Raymond JA. A DUF3494 ice-binding protein with a root cap domain in a streptophyte glacier ice alga. FRONTIERS IN PLANT SCIENCE 2024; 14:1306511. [PMID: 38250448 PMCID: PMC10796529 DOI: 10.3389/fpls.2023.1306511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 12/19/2023] [Indexed: 01/23/2024]
Abstract
Ice-binding proteins (IBPs) of the DUF3494 type have been found in many ice-associated unicellular photoautotrophs, including chlorophytes, haptophytes, diatoms and a cyanobacterium. Unrelated IBPs have been found in many land plants (streptophytes). Here we looked for IBPs in two streptophyte algae that grow only on glaciers, a group in which IBPs have not previously been examined. The two species, Ancylonema nordenskioeldii and Ancylonema. alaskanum, belong to the class Zygnematophyceae, whose members are the closest relatives to all land plants. We found that one of them, A. nordenskioeldii, expresses a DUF3494-type IBP that is similar to those of their chlorophyte ancestors and that has not previously been found in any streptophytes. The protein is unusual in having what appears to be a perfect array of TXT motifs that have been implicated in water or ice binding. The IBP strongly binds to ice and almost certainly has a role in mitigating the daily freeze-thaw cycles that the alga is exposed to during late summer. No IBP was found in the second species, A. alaskanum, which may rely more on glycerol production for its freeze-thaw tolerance. The IBP is also unusual in having a 280-residue domain with a β sandwich structure (which we designate as the DPH domain) that is characteristic of root cap proteins of land plants, and that may have a role in forming IBP oligomers. We also examined existing transcriptome data obtained from land plants to better understand the tissue and temperature dependence of expression of this domain.
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Affiliation(s)
| | - Daniel Remias
- Department of Environment and Biodiversity, Paris Lodron University Salzburg, Salzburg, Austria
| | | | - James A. Raymond
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
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Lyu X, Cui W, Ji M, Wang W, Zhang Z, Liu Y. The distribution and drivers of microbial pigments in the cryoconite of four Tibetan glaciers. Environ Microbiol 2024; 26:e16550. [PMID: 38087431 DOI: 10.1111/1462-2920.16550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 11/24/2023] [Indexed: 01/30/2024]
Abstract
Microbial pigments play a significant role in glacier albedo reduction, thereby contributing to accelerated glacier retreat. The Tibetan Plateau has experienced rapid glacier retreat in recent decades due to global warming, yet there is limited understanding of microbial pigment distribution in the region. Here, we investigated the pigment concentration and composition in cryoconite from four glaciers. Our results showed that chlorophylls were the dominant pigments in Palong No. 4 (PL) and Jiemayangzong (JMYZ) glaciers located in the south of the Tibetan Plateau, while carotenoids were dominant in Qiangyong (QY) and Tanggula (TGL) glaciers located in the central region. Additionally, the chlorophyll b to chlorophyll a ratio, which is an indicator of the algae-to-cyanobacteria ratio, was higher in PL and JMYZ compared to QY and TGL. By using Random Forest Regression and Structural Equation Modelling, we determined that the concentrations of chlorophyll a, chlorophyll b, and carotenoids were associated with autotrophic bacteria relative abundance, climatic factors, and a combination of bacterial and climatic factors, respectively. This study is the first to describe the distribution of microbial pigments in cryoconite from Tibetan glaciers, providing additional support on the influence of algal pigment on glacier retreat.
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Affiliation(s)
- Xianfu Lyu
- The Environment Change & Multi-sphere Interaction Team (ECMI), State Key Laboratory of Tibetan Plateau Earth System, Environment and Resource (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Wanzhe Cui
- Center for the Pan-third Pole Environment, Lanzhou University, Lanzhou, China
| | - Mukan Ji
- Center for the Pan-third Pole Environment, Lanzhou University, Lanzhou, China
| | - Wenqiang Wang
- Center for the Pan-third Pole Environment, Lanzhou University, Lanzhou, China
| | - Zhihao Zhang
- The Environment Change & Multi-sphere Interaction Team (ECMI), State Key Laboratory of Tibetan Plateau Earth System, Environment and Resource (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yongqin Liu
- The Environment Change & Multi-sphere Interaction Team (ECMI), State Key Laboratory of Tibetan Plateau Earth System, Environment and Resource (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- Center for the Pan-third Pole Environment, Lanzhou University, Lanzhou, China
- University of Chinese Academy of Sciences, Beijing, China
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7
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Glaser K, Kammann S, Plag N, Dressler M. Ecophysiological performance of terrestrial diatoms isolated from biocrusts of coastal sand dunes. Front Microbiol 2023; 14:1279151. [PMID: 38169811 PMCID: PMC10758497 DOI: 10.3389/fmicb.2023.1279151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
Abstract
Terrestrial diatoms are widespread in a large variety of habitats and are regularly recorded in biocrusts. Although diatoms have long been known to live in terrestrial habitats, only a few studies have focused on their diversity of ecophysiology. Here we present a study on the ecophysiological performance of five terrestrial diatom cultures from biocrusts, which were collected in sand dunes of the German coast of the Baltic Sea. The sampling sites were selected along a gradient of human impacts on the dunes. The richness of diatom species, roughly estimated from permanent slides, was around 30 species per sampling site. The species abundance was calculated in the same way revealing a high proportion of broken diatom frustules. All diatom cultures established in the laboratory showed no photoinhibition and high oxygen production along a light gradient. The desiccation tolerance differed among the strains, with high recovery observed for Hantzschia abundans and Achnanthes coarctata and low to no recovery for Pinnularia borealis and Pinnularia intermedia. The maximum growth rate for most strains was between 25 and 30°C. These temperatures can be easily reached in their natural environments. Nevertheless, during short-term exposure to elevated temperatures, oxygen production was recorded up to 35°C. Interestingly, two of five diatom cultures (Hantzschia abundans and Pinnularia borealis) produced mycosporine-like amino acids. These UV-protective substances are known from marine diatoms but not previously reported in terrestrial diatoms.
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Affiliation(s)
- Karin Glaser
- Institute for Biosciences, Biology/Ecology, TU Bergakademie Freiberg, Freiberg, Germany
| | - Sandra Kammann
- Institute of Biological Sciences, Applied Ecology and Phycology, University of Rostock, Rostock, Germany
| | - Niklas Plag
- Institute of Biological Sciences, Applied Ecology and Phycology, University of Rostock, Rostock, Germany
| | - Mirko Dressler
- Department of Physical Geography, Institute for Geography and Geology, University of Greifswald, Greifswald, Germany
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Jaarsma AH, Zervas A, Sipes K, Campuzano Jiménez F, Smith AC, Svendsen LV, Thøgersen MS, Stougaard P, Benning LG, Tranter M, Anesio AM. The undiscovered biosynthetic potential of the Greenland Ice Sheet microbiome. Front Microbiol 2023; 14:1285791. [PMID: 38149278 PMCID: PMC10749974 DOI: 10.3389/fmicb.2023.1285791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/24/2023] [Indexed: 12/28/2023] Open
Abstract
The Greenland Ice Sheet is a biome which is mainly microbially driven. Several different niches can be found within the glacial biome for those microbes able to withstand the harsh conditions, e.g., low temperatures, low nutrient conditions, high UV radiation in summer, and contrasting long and dark winters. Eukaryotic algae can form blooms during the summer on the ice surface, interacting with communities of bacteria, fungi, and viruses. Cryoconite holes and snow are also habitats with their own microbial community. Nevertheless, the microbiome of supraglacial habitats remains poorly studied, leading to a lack of representative genomes from these environments. Under-investigated extremophiles, like those living on the Greenland Ice Sheet, may provide an untapped reservoir of chemical diversity that is yet to be discovered. In this study, an inventory of the biosynthetic potential of these organisms is made, through cataloging the presence of biosynthetic gene clusters in their genomes. There were 133 high-quality metagenome-assembled genomes (MAGs) and 28 whole genomes of bacteria obtained from samples of the ice sheet surface, cryoconite, biofilm, and snow using culturing-dependent and -independent approaches. AntiSMASH and BiG-SCAPE were used to mine these genomes and subsequently analyze the resulting predicted gene clusters. Extensive sets of predicted Biosynthetic Gene Clusters (BGCs) were collected from the genome collection, with limited overlap between isolates and MAGs. Additionally, little overlap was found in the biosynthetic potential among different environments, suggesting specialization of organisms in specific habitats. The median number of BGCs per genome was significantly higher for the isolates compared to the MAGs. The most talented producers were found among Proteobacteria. We found evidence for the capacity of these microbes to produce antimicrobials, carotenoid pigments, siderophores, and osmoprotectants, indicating potential survival mechanisms to cope with extreme conditions. The majority of identified BGCs, including those in the most prevalent gene cluster families, have unknown functions, presenting a substantial potential for bioprospecting. This study underscores the diverse biosynthetic potential in Greenland Ice Sheet genomes, revealing insights into survival strategies and highlighting the need for further exploration and characterization of these untapped resources.
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Affiliation(s)
- Ate H. Jaarsma
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | - Athanasios Zervas
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | - Katie Sipes
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | | | | | | | | | - Peter Stougaard
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | - Liane G. Benning
- German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
- Department of Earth Sciences, Freie Universität Berlin, Berlin, Germany
| | - Martyn Tranter
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
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Van de Poel B, de Vries J. Evolution of ethylene as an abiotic stress hormone in streptophytes. ENVIRONMENTAL AND EXPERIMENTAL BOTANY 2023; 214:105456. [PMID: 37780400 PMCID: PMC10518463 DOI: 10.1016/j.envexpbot.2023.105456] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 10/03/2023]
Abstract
All land plants modulate their growth and physiology through intricate signaling cascades. The majority of these are at least modulated-and often triggered-by phytohormones. Over the past decade, it has become apparent that some phytohormones have an evolutionary origin that runs deeper than plant terrestrialization-many emerged in the streptophyte algal progenitors of land plants. Ethylene is such a case. Here we synthesize the current knowledge on the evolution of the phytohormone ethylene and speculate about its deeply conserved role in adjusting stress responses of streptophytes for more than half a billion years of evolution.
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Affiliation(s)
- Bram Van de Poel
- Molecular Plant Hormone Physiology lab, Division of Crop Biotechnics, Department of Biosystems, University of Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
- KU Leuven Plant Institute (LPI), University of Leuven, Kasteelpark Arenberg 31, 3001 Leuven, Belgium
| | - Jan de Vries
- University of Goettingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany
- University of Goettingen, Campus Institute Data Science (CIDAS), Goldschmidstr. 1, 37077 Goettingen, Germany
- University of Goettingen, Goettingen Center for Molecular Biosciences (GZMB), Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany
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10
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Liao J, Wei X, Tao K, Deng G, Shu J, Qiao Q, Chen G, Wei Z, Fan M, Saud S, Fahad S, Chen S. Phenoloxidases: catechol oxidase - the temporary employer and laccase - the rising star of vascular plants. HORTICULTURE RESEARCH 2023; 10:uhad102. [PMID: 37786731 PMCID: PMC10541563 DOI: 10.1093/hr/uhad102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 05/16/2023] [Accepted: 05/05/2023] [Indexed: 10/04/2023]
Abstract
Phenolics are vital for the adaptation of plants to terrestrial habitats and for species diversity. Phenoloxidases (catechol oxidases, COs, and laccases, LACs) are responsible for the oxidation and polymerization of phenolics. However, their origin, evolution, and differential roles during plant development and land colonization are unclear. We performed the phylogeny, domain, amino acids, compositional biases, and intron analyses to clarify the origin and evolution of COs and LACs, and analysed the structure, selective pressure, and chloroplast targeting to understand the species-dependent distribution of COs. We found that Streptophyta COs were not homologous to the Chlorophyta tyrosinases (TYRs), and might have been acquired by horizontal gene transfer from bacteria. COs expanded in bryophytes. Structural-functionality and selective pressure were partially responsible for the species-dependent retention of COs in embryophytes. LACs emerged in Zygnemaphyceae, having evolved from ascorbate oxidases (AAOs), and prevailed in the vascular plants and strongly expanded in seed plants. COs and LACs coevolved with the phenolic metabolism pathway genes. These results suggested that TYRs and AAOs were the first-stage phenoloxidases in Chlorophyta. COs might be the second key for the early land colonization. LACs were the third one (dominating in the vascular plants) and might be advantageous for diversified phenol substrates and the erect growth of plants. This work provided new insights into how phenoloxidases evolved and were devoted to plant evolution.
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Affiliation(s)
- Jugou Liao
- School of Ecology and Environmental Sciences, Yunnan University; Biocontrol Engineering Research Center of Crop Diseases & Pests, Yunnan Province, Kunming 650091, China
| | - Xuemei Wei
- School of Engineering, Dali University, Dali, Yunnan Province, 671003, China
| | - Keliang Tao
- School of Life Science, Yunnan University, Yunnan Province, Kunming 650091, China
| | - Gang Deng
- College of Horticulture and Landscape, Yunnan Agricultural University, Yunnan Province, Kunming 650091, China
| | - Jie Shu
- School of Life Science, Yunnan University, Yunnan Province, Kunming 650091, China
| | - Qin Qiao
- College of Horticulture and Landscape, Yunnan Agricultural University, Yunnan Province, Kunming 650091, China
| | - Gonglin Chen
- School of Ecology and Environmental Sciences, Yunnan University; Biocontrol Engineering Research Center of Crop Diseases & Pests, Yunnan Province, Kunming 650091, China
| | - Zhuo Wei
- School of Ecology and Environmental Sciences, Yunnan University; Biocontrol Engineering Research Center of Crop Diseases & Pests, Yunnan Province, Kunming 650091, China
| | - Meihui Fan
- School of Ecology and Environmental Sciences, Yunnan University; Biocontrol Engineering Research Center of Crop Diseases & Pests, Yunnan Province, Kunming 650091, China
| | - Shah Saud
- College of Life Science, Linyi University, Linyi, Shandong 276000, China
| | - Shah Fahad
- Department of Agronomy, Abdul Wali Khan University Mardan, Khyber Pakhtunkhwa 23200, Pakistan
| | - Suiyun Chen
- School of Ecology and Environmental Sciences, Yunnan University; Biocontrol Engineering Research Center of Crop Diseases & Pests, Yunnan Province, Kunming 650091, China
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11
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Chen Q, Lan P, Tan S, Banwell MG. The Palladium-Catalyzed Glycosylation of Halotropones. Org Lett 2023; 25:384-388. [PMID: 36606750 DOI: 10.1021/acs.orglett.2c04099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A range of mono- and disaccharides, including glucose derivative 10, has been cleanly coupled, in the presence of a Pd catalyst, with various halogenated and structurally distinctive tropones, including "parent" compound 11, to afford the corresponding α- and β-anomeric forms of the tropolone glycosides, e.g., 12 and 13, respectively. Varying the ligand used influences the anomer distribution significantly and such that either the α- or β-form predominates. Notable chemo- and regioselectivities are observed when dihalogenated troponoids are employed as coupling partners.
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Affiliation(s)
- Qi Chen
- Institute for Advanced and Applied Chemical Synthesis, College of Pharmacy, Jinan University, Guangzhou, Guangdong510632, China
| | - Ping Lan
- Institute for Advanced and Applied Chemical Synthesis, College of Pharmacy, Jinan University, Guangzhou, Guangdong510632, China
| | - Shen Tan
- Institute for Advanced and Applied Chemical Synthesis, College of Pharmacy, Jinan University, Guangzhou, Guangdong510632, China
| | - Martin G Banwell
- Institute for Advanced and Applied Chemical Synthesis, College of Pharmacy, Jinan University, Guangzhou, Guangdong510632, China.,Guangdong Key Laboratory for Research and the Development of Natural Drugs, The Marine Biomedical Research Institute, Guangdong Medical University,Zhanjiang, Guangdong524023, China
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12
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Davies KM, Landi M, van Klink JW, Schwinn KE, Brummell DA, Albert NW, Chagné D, Jibran R, Kulshrestha S, Zhou Y, Bowman JL. Evolution and function of red pigmentation in land plants. ANNALS OF BOTANY 2022; 130:613-636. [PMID: 36070407 PMCID: PMC9670752 DOI: 10.1093/aob/mcac109] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 09/05/2022] [Indexed: 05/10/2023]
Abstract
BACKGROUND Land plants commonly produce red pigmentation as a response to environmental stressors, both abiotic and biotic. The type of pigment produced varies among different land plant lineages. In the majority of species they are flavonoids, a large branch of the phenylpropanoid pathway. Flavonoids that can confer red colours include 3-hydroxyanthocyanins, 3-deoxyanthocyanins, sphagnorubins and auronidins, which are the predominant red pigments in flowering plants, ferns, mosses and liverworts, respectively. However, some flowering plants have lost the capacity for anthocyanin biosynthesis and produce nitrogen-containing betalain pigments instead. Some terrestrial algal species also produce red pigmentation as an abiotic stress response, and these include both carotenoid and phenolic pigments. SCOPE In this review, we examine: which environmental triggers induce red pigmentation in non-reproductive tissues; theories on the functions of stress-induced pigmentation; the evolution of the biosynthetic pathways; and structure-function aspects of different pigment types. We also compare data on stress-induced pigmentation in land plants with those for terrestrial algae, and discuss possible explanations for the lack of red pigmentation in the hornwort lineage of land plants. CONCLUSIONS The evidence suggests that pigment biosynthetic pathways have evolved numerous times in land plants to provide compounds that have red colour to screen damaging photosynthetically active radiation but that also have secondary functions that provide specific benefits to the particular land plant lineage.
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Affiliation(s)
| | - Marco Landi
- Department of Agriculture, Food and Environment, University of Pisa, Italy
| | - John W van Klink
- The New Zealand Institute for Plant and Food Research Limited, Department of Chemistry, Otago University, Dunedin, New Zealand
| | - Kathy E Schwinn
- The New Zealand Institute for Plant and Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - David A Brummell
- The New Zealand Institute for Plant and Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - Nick W Albert
- The New Zealand Institute for Plant and Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - David Chagné
- The New Zealand Institute for Plant and Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - Rubina Jibran
- The New Zealand Institute for Plant and Food Research Limited, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
| | - Samarth Kulshrestha
- The New Zealand Institute for Plant and Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - Yanfei Zhou
- The New Zealand Institute for Plant and Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - John L Bowman
- School of Biological Sciences, Monash University, Melbourne, VIC, Australia
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13
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Pigment signatures of algal communities and their implications for glacier surface darkening. Sci Rep 2022; 12:17643. [PMID: 36271236 PMCID: PMC9587043 DOI: 10.1038/s41598-022-22271-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 10/12/2022] [Indexed: 01/18/2023] Open
Abstract
Blooms of pigmented algae darken the surface of glaciers and ice sheets, thereby enhancing solar energy absorption and amplifying ice and snow melt. The impacts of algal pigment and community composition on surface darkening are still poorly understood. Here, we characterise glacier ice and snow algal pigment signatures on snow and bare ice surfaces and study their role in photophysiology and energy absorption on three glaciers in Southeast Greenland. Purpurogallin and astaxanthin esters dominated the glacier ice and snow algal pigment pools (mass ratios to chlorophyll a of 32 and 56, respectively). Algal biomass and pigments impacted chromophoric dissolved organic matter concentrations. Despite the effective absorption of astaxanthin esters at wavelengths where incoming irradiance peaks, the cellular energy absorption of snow algae was 95% lower than anticipated from their pigmentation, due to pigment packaging. The energy absorption of glacier ice algae was consequently ~ 5 × higher. On bare ice, snow algae may have locally contributed up to 13% to total biological radiative forcing, despite contributing 44% to total biomass. Our results give new insights into the impact of algal community composition on bare ice energy absorption and biomass accumulation during snow melt.
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14
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Trumhová K, Klimešová V, Pichrtová M. Seasonal Dynamics of Zygnema (Zygnematophyceae) Mats from the Austrian Alps. MICROBIAL ECOLOGY 2022:10.1007/s00248-022-02105-6. [PMID: 36053304 DOI: 10.1007/s00248-022-02105-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Filamentous green algae of the genus Zygnema are an essential part of hydro-terrestrial ecosystems. Despite several studies on their resistance to natural stresses, little is known about the composition of their assemblages and the changes they undergo over time. Two sites at altitudes above 2200 m a.s.l. in the Austrian Alps were selected for a 2-year observation period and sampled five times. Molecular phylogenetic analysis of the 152 isolated strains of Zygnema sp. was performed based on the rbcL and trnG sequences. Seven genotypes were found at these sites during the samplings, but their proportion varied throughout the seasons. The site with a more stable water regime also had a more stable representation of genotypes, in contrast to the site with fluctuating water availability. The mats formed resistant pre-akinetes at the end of the season with reduced photosynthetic activity. Contrary to expectations, the mats were not exposed to extremely cold temperatures in winter due to snow cover. Some genotypes have been previously observed at this site, indicating that the population composition is stable. This work highlights the importance of resistant pre-akinetes in surviving winter conditions, the ability of algae to re-establish mats, and the need to address the hidden diversity of the genus Zygnema.
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Affiliation(s)
- Kateřina Trumhová
- Faculty of Science, Department of Botany, Charles University, Benátská 2, 128 00, Prague, Czech Republic.
| | - Vanda Klimešová
- Institute of Criminalistics Prague, Strojnická 27, 170 89, Prague, Czech Republic
| | - Martina Pichrtová
- Faculty of Science, Department of Botany, Charles University, Benátská 2, 128 00, Prague, Czech Republic
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15
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Permann C, Becker B, Holzinger A. Temperature- and light stress adaptations in Zygnematophyceae: The challenges of a semi-terrestrial lifestyle. FRONTIERS IN PLANT SCIENCE 2022; 13:945394. [PMID: 35928713 PMCID: PMC9343959 DOI: 10.3389/fpls.2022.945394] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Streptophyte green algae comprise the origin of land plants and therefore life on earth as we know it today. While terrestrialization opened new habitats, leaving the aquatic environment brought additional abiotic stresses. More-drastic temperature shifts and high light levels are major abiotic stresses in semi-terrestrial habitats, in addition to desiccation, which has been reviewed elsewhere. Zygnematophyceae, a species-rich class of streptophyte green algae, is considered a sister-group to embryophytes. They have developed a variety of avoidance and adaptation mechanisms to protect against temperature extremes and high radiation in the form of photosynthetically active and ultraviolet radiation (UV) radiation occurring on land. Recently, knowledge of transcriptomic and metabolomic changes as consequences of these stresses has become available. Land-plant stress-signaling pathways producing homologs of key enzymes have been described in Zygnematophyceae. An efficient adaptation strategy is their mat-like growth habit, which provides self-shading and protects lower layers from harmful radiation. Additionally, Zygnematophyceae possess phenolic compounds with UV-screening ability. Resting stages such as vegetative pre-akinetes tolerate freezing to a much higher extent than do young cells. Sexual reproduction occurs by conjugation without the formation of flagellated male gametes, which can be seen as an advantage in water-deficient habitats. The resulting zygospores possess a multilayer cell wall, contributing to their resistance to terrestrial conditions. Especially in the context of global change, understanding temperature and light tolerance is crucial.
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Affiliation(s)
- Charlotte Permann
- Department of Botany, Functional Plant Biology, University of Innsbruck, Innsbruck, Austria
| | - Burkhard Becker
- Department of Biology, Institute for Plant Sciences, University of Cologne, Cologne, Germany
| | - Andreas Holzinger
- Department of Botany, Functional Plant Biology, University of Innsbruck, Innsbruck, Austria
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16
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Perini L, Gostinčar C, Likar M, Frisvad JC, Kostanjšek R, Nicholes M, Williamson C, Anesio AM, Zalar P, Gunde-Cimerman N. Interactions of Fungi and Algae from the Greenland Ice Sheet. MICROBIAL ECOLOGY 2022:10.1007/s00248-022-02033-5. [PMID: 35608637 DOI: 10.1007/s00248-022-02033-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Heavily pigmented glacier ice algae Ancylonema nordenskiöldii and Ancylonema alaskanum (Zygnematophyceae, Streptophyta) reduce the bare ice albedo of the Greenland Ice Sheet, amplifying melt from the largest cryospheric contributor to eustatic sea-level rise. Little information is available about glacier ice algae interactions with other microbial communities within the surface ice environment, including fungi, which may be important for sustaining algal bloom development. To address this substantial knowledge gap and investigate the nature of algal-fungal interactions, an ex situ co-cultivation experiment with two species of fungi, recently isolated from the surface of the Greenland Ice Sheet (here proposed new species Penicillium anthracinoglaciei Perini, Frisvad and Zalar, Mycobank (MB 835602), and Articulospora sp.), and the mixed microbial community dominated by glacier ice algae was performed. The utilization of the dark pigment purpurogallin carboxylic acid-6-O-β-D-glucopyranoside (C18H18O12) by the two fungi was also evaluated in a separate experiment. P. anthracinoglaciei was capable of utilizing and converting the pigment to purpurogallin carboxylic acid, possibly using the sugar moiety as a nutrient source. Furthermore, after 3 weeks of incubation in the presence of P. anthracinoglaciei, a significantly slower decline in the maximum quantum efficiency (Fv/Fm, inverse proxy of algal stress) in glacier ice algae, compared to other treatments, was evident, suggesting a positive relationship between these species. Articulospora sp. did uptake the glycosylated purpurogallin, but did not seem to be involved in its conversion to aglycone derivative. At the end of the incubation experiments and, in conjunction with increased algal mortality, we detected a substantially increasing presence of the zoosporic fungi Chytridiomycota suggesting an important role for them as decomposers or parasites of glacier ice algae.
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Affiliation(s)
- L Perini
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia.
- Department of Environmental Science, Aarhus University, 4000, Roskilde, Denmark.
| | - C Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
- Lars Bolund Institute of Regenerative Medicine, BGI-Qingdao, Qingdao, 266555, China
| | - M Likar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - J C Frisvad
- Department of Biotechnology and Biomedicine, Fungal Chemodiversity, Technical University of Denmark, Søltofts Plads, Building 221, 2800, Kgs. Lyngby, Denmark
| | - R Kostanjšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - M Nicholes
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK
| | - C Williamson
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK
| | - A M Anesio
- Department of Environmental Science, Aarhus University, 4000, Roskilde, Denmark
| | - P Zalar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - N Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
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17
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Nascimento LBDS, Tattini M. Beyond Photoprotection: The Multifarious Roles of Flavonoids in Plant Terrestrialization. Int J Mol Sci 2022; 23:5284. [PMID: 35563675 PMCID: PMC9101737 DOI: 10.3390/ijms23095284] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/29/2022] [Accepted: 05/06/2022] [Indexed: 02/01/2023] Open
Abstract
Plants evolved an impressive arsenal of multifunctional specialized metabolites to cope with the novel environmental pressures imposed by the terrestrial habitat when moving from water. Here we examine the multifarious roles of flavonoids in plant terrestrialization. We reason on the environmental drivers, other than the increase in UV-B radiation, that were mostly responsible for the rise of flavonoid metabolism and how flavonoids helped plants in land conquest. We are reasonably based on a nutrient-deficiency hypothesis for the replacement of mycosporine-like amino acids, typical of streptophytic algae, with the flavonoid metabolism during the water-to-land transition. We suggest that flavonoids modulated auxin transport and signaling and promoted the symbiosis between plants and fungi (e.g., arbuscular mycorrhizal, AM), a central event for the conquest of land by plants. AM improved the ability of early plants to take up nutrients and water from highly impoverished soils. We offer evidence that flavonoids equipped early land plants with highly versatile "defense compounds", essential for the new set of abiotic and biotic stressors imposed by the terrestrial environment. We conclude that flavonoids have been multifunctional since the appearance of plants on land, not only acting as UV filters but especially improving both nutrient acquisition and biotic stress defense.
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Affiliation(s)
| | - Massimiliano Tattini
- Institute for Sustainable Plant Protection (IPSP), National Research Council of Italy, 50019 Sesto Fiorentino, Florence, Italy;
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18
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Extremophilic Microorganisms in Central Europe. Microorganisms 2021; 9:microorganisms9112326. [PMID: 34835450 PMCID: PMC8620676 DOI: 10.3390/microorganisms9112326] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 11/17/2022] Open
Abstract
Extremophiles inhabit a wide variety of environments. Here we focus on extremophiles in moderate climates in central Europe, and particularly in Slovenia. Although multiple types of stress often occur in the same habitat, extremophiles are generally combined into groups according to the main stressor to which they are adapted. Several types of extremophiles, e.g., oligotrophs, are well represented and diverse in subsurface environments and karst regions. Psychrophiles thrive in ice caves and depressions with eternal snow and ice, with several globally distributed snow algae and psychrophilic bacteria that have been discovered in alpine glaciers. However, this area requires further research. Halophiles thrive in salterns while thermophiles inhabit thermal springs, although there is little data on such microorganisms in central Europe, despite many taxa being found globally. This review also includes the potential use of extremophiles in biotechnology and bioremediation applications.
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19
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Williamson CJ, Turpin-Jelfs T, Nicholes MJ, Yallop ML, Anesio AM, Tranter M. Macro-Nutrient Stoichiometry of Glacier Algae From the Southwestern Margin of the Greenland Ice Sheet. FRONTIERS IN PLANT SCIENCE 2021; 12:673614. [PMID: 34262580 PMCID: PMC8273243 DOI: 10.3389/fpls.2021.673614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 04/23/2021] [Indexed: 06/13/2023]
Abstract
Glacier algae residing within the surface ice of glaciers and ice sheets play globally significant roles in biogeochemical cycling, albedo feedbacks, and melt of the world's cryosphere. Here, we present an assessment of the macro-nutrient stoichiometry of glacier algal assemblages from the southwestern Greenland Ice Sheet (GrIS) margin, where widespread glacier algal blooms proliferate during summer melt seasons. Samples taken during the mid-2019 ablation season revealed overall lower cellular carbon (C), nitrogen (N), and phosphorus (P) content than predicted by standard microalgal cellular content:biovolume relationships, and elevated C:N and C:P ratios in all cases, with an overall estimated C:N:P of 1,997:73:1. We interpret lower cellular macro-nutrient content and elevated C:N and C:P ratios to reflect adaptation of glacier algal assemblages to their characteristic oligotrophic surface ice environment. Such lower macro-nutrient requirements would aid the proliferation of blooms across the nutrient poor cryosphere in a warming world. Up-scaling of our observations indicated the potential for glacier algal assemblages to accumulate ∼ 29 kg C km2 and ∼ 1.2 kg N km2 within our marginal surface ice location by the mid-ablation period (early August), confirming previous modeling estimates. While the long-term fate of glacier algal autochthonous production within surface ice remains unconstrained, data presented here provide insight into the possible quality of dissolved organic matter that may be released by assemblages into the surface ice environment.
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Affiliation(s)
- Christopher J. Williamson
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Thomas Turpin-Jelfs
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Miranda J. Nicholes
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Marian L. Yallop
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | | | - Martyn Tranter
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
- Department of Environmental Science, Aarhus University, Aarhus, Denmark
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20
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Procházková L, Řezanka T, Nedbalová L, Remias D. Unicellular versus Filamentous: The Glacial Alga Ancylonema alaskana comb. et stat. nov. and Its Ecophysiological Relatedness to Ancylonema nordenskioeldii (Zygnematophyceae, Streptophyta). Microorganisms 2021; 9:1103. [PMID: 34065466 PMCID: PMC8161032 DOI: 10.3390/microorganisms9051103] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/15/2021] [Accepted: 05/17/2021] [Indexed: 11/16/2022] Open
Abstract
Melting polar and alpine ice surfaces frequently exhibit blooms of dark pigmented algae. These microbial extremophiles significantly reduce the surface albedo of glaciers, thus accelerating melt rates. However, the ecology, physiology and taxonomy of cryoflora are not yet fully understood. Here, a Swiss and an Austrian glacier dominated either by filamentous Ancylonema nordenskioeldii or unicellular Mesotaenium berggrenii var. alaskanum, were sampled. Molecular analysis showed that both species are closely related, sharing identical chloroplast morphologies (parietal-lobed for Ancylonema vs. axial plate-like for Mesotaenium sensu stricto), thus the unicellular species was renamed Ancylonema alaskana. Moreover, an ecophysiological comparison of the two species was performed: pulse-amplitude modulated (PAM) fluorometry confirmed that they have a high tolerance to elevated solar irradiation, the physiological light preferences reflected the conditions in the original habitat; nonetheless, A. nordenskioeldii was adapted to higher irradiances while the photosystems of A. alaskana were able to use efficiently low irradiances. Additionally, the main vacuolar polyphenol, which effectively shields the photosystems, was identical in both species. Also, about half of the cellular fatty acids were polyunsaturated, and the lipidome profiles dominated by triacylglycerols were very similar. The results indicate that A. alaskana is physiologically very similar and closely related but genetically distinct to A. nordenskioeldii.
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Affiliation(s)
- Lenka Procházková
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 44 Prague, Czech Republic;
| | - Tomáš Řezanka
- Institute of Microbiology, The Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic;
| | - Linda Nedbalová
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 44 Prague, Czech Republic;
- Centre for Phycology, Institute of Botany of the Czech Academy of Sciences, Dukelská 135, 379 82 Třeboň, Czech Republic
| | - Daniel Remias
- School of Engineering, University of Applied Sciences Upper Austria, Stelzhamerstr. 23, 4600 Wels, Austria
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21
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Gálvez FE, Saldarriaga-Córdoba M, Huovinen P, Silva AX, Gómez I. Revealing the Characteristics of the Antarctic Snow Alga Chlorominima collina gen. et sp. nov. Through Taxonomy, Physiology, and Transcriptomics. FRONTIERS IN PLANT SCIENCE 2021; 12:662298. [PMID: 34163502 PMCID: PMC8215615 DOI: 10.3389/fpls.2021.662298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/10/2021] [Indexed: 05/13/2023]
Abstract
Snow algae play crucial roles in cold ecosystems, however, many aspects related to their biology, adaptations and especially their diversity are not well known. To improve the identification of snow algae from colored snow, in the present study we used a polyphasic approach to describe a new Antarctic genus, Chlorominima with the species type Chlorominima collina. This new taxon was isolated of colored snow collected from the Collins Glacier (King George Island) in the Maritime Antarctic region. Microscopy revealed biflagellated ellipsoidal cells with a rounded posterior end, a C-shaped parietal chloroplast without a pyrenoid, eyespot, and discrete papillae. Several of these characteristics are typical of the genus Chloromonas, but the new isolate differs from the described species of this genus by the unusual small size of the cells, the presence of several vacuoles, the position of the nucleus and the shape of the chloroplast. Molecular analyzes confirm that the isolated alga does not belong to Chloromonas and therefore forms an independent lineage, which is closely related to other unidentified Antarctic and Arctic strains, forming a polar subclade in the Stephanosphaerinia phylogroup within the Chlamydomonadales. Secondary structure comparisons of the ITS2 rDNA marker support the idea that new strain is a distinct taxon within of Caudivolvoxa. Physiological experiments revealed psychrophilic characteristics, which are typical of true snow algae. This status was confirmed by the partial transcriptome obtained at 2°C, in which various cold-responsive and cryoprotective genes were identified. This study explores the systematics, cold acclimatization strategies and their implications for the Antarctic snow flora.
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Affiliation(s)
- Francisca E. Gálvez
- Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
- *Correspondence: Francisca E. Gálvez,
| | - Mónica Saldarriaga-Córdoba
- Centro de Investigación en Recursos Naturales y Sustentabilidad (CIRENYS), Universidad Bernardo O’Higgins, Santiago, Chile
| | - Pirjo Huovinen
- Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
| | - Andrea X. Silva
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- AUSTRAL-omics, Vicerrectoría de Investigación, Desarrollo y Creación Artística, Universidad Austral de Chile, Valdivia, Chile
| | - Iván Gómez
- Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
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22
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Žárský J, Žárský V, Hanáček M, Žárský V. Cryogenian Glacial Habitats as a Plant Terrestrialisation Cradle - The Origin of the Anydrophytes and Zygnematophyceae Split. FRONTIERS IN PLANT SCIENCE 2021; 12:735020. [PMID: 35154170 PMCID: PMC8829067 DOI: 10.3389/fpls.2021.735020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 12/17/2021] [Indexed: 05/05/2023]
Abstract
For tens of millions of years (Ma), the terrestrial habitats of Snowball Earth during the Cryogenian period (between 720 and 635 Ma before present-Neoproterozoic Era) were possibly dominated by global snow and ice cover up to the equatorial sublimative desert. The most recent time-calibrated phylogenies calibrated not only on plants but on a comprehensive set of eukaryotes indicate that within the Streptophyta, multicellular charophytes (Phragmoplastophyta) evolved in the Mesoproterozoic to the early Neoproterozoic. At the same time, Cryogenian is the time of the likely origin of the common ancestor of Zygnematophyceae and Embryophyta and later, also of the Zygnematophyceae-Embryophyta split. This common ancestor is proposed to be called Anydrophyta; here, we use anydrophytes. Based on the combination of published phylogenomic studies and estimated diversification time comparisons, we deem it highly likely that anydrophytes evolved in response to Cryogenian cooling. Also, later in the Cryogenian, secondary simplification of multicellular anydrophytes and loss of flagella resulted in Zygnematophyceae diversification as an adaptation to the extended cold glacial environment. We propose that the Marinoan geochemically documented expansion of first terrestrial flora has been represented not only by Chlorophyta but also by Streptophyta, including the anydrophytes, and later by Zygnematophyceae, thriving on glacial surfaces until today. It is possible that multicellular early Embryophyta survived in less abundant (possibly relatively warmer) refugia, relying more on mineral substrates, allowing the retention of flagella-based sexuality. The loss of flagella and sexual reproduction by conjugation evolved in Zygnematophyceae and zygomycetous fungi during the Cryogenian in a remarkably convergent way. Thus, we support the concept that the important basal cellular adaptations to terrestrial environments were exapted in streptophyte algae for terrestrialization and propose that this was stimulated by the adaptation to glacial habitats dominating the Cryogenian Snowball Earth. Including the glacial lifestyle when considering the rise of land plants increases the parsimony of connecting different ecological, phylogenetic, and physiological puzzles of the journey from aquatic algae to terrestrial floras.
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Affiliation(s)
- Jakub Žárský
- CryoEco Research Group, Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
- *Correspondence: Jakub Žárský,
| | - Vojtěch Žárský
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czechia
| | - Martin Hanáček
- Polar-Geo-Lab, Department of Geography, Faculty of Science, Masaryk University, Brno, Czechia
- Regional Museum in Jeseník, Jeseník, Czechia
| | - Viktor Žárský
- Laboratory of Cell Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
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23
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Hoham RW, Remias D. Snow and Glacial Algae: A Review 1. JOURNAL OF PHYCOLOGY 2020; 56:264-282. [PMID: 31825096 PMCID: PMC7232433 DOI: 10.1111/jpy.12952] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 11/20/2019] [Indexed: 05/03/2023]
Abstract
Snow or glacial algae are found on all continents, and most species are in the Chlamydomonadales (Chlorophyta) and Zygnematales (Streptophyta). Other algal groups include euglenoids, cryptomonads, chrysophytes, dinoflagellates, and cyanobacteria. They may live under extreme conditions of temperatures near 0°C, high irradiance levels in open exposures, low irradiance levels under tree canopies or deep in snow, acidic pH, low conductivity, and desiccation after snow melt. These primary producers may color snow green, golden-brown, red, pink, orange, or purple-grey, and they are part of communities that include other eukaryotes, bacteria, archaea, viruses, and fungi. They are an important component of the global biosphere and carbon and water cycles. Life cycles in the Chlamydomonas-Chloromonas-Chlainomonas complex include migration of flagellates in liquid water and formation of resistant cysts, many of which were identified previously as other algae. Species differentiation has been updated through the use of metagenomics, lipidomics, high-throughput sequencing (HTS), multi-gene analysis, and ITS. Secondary metabolites (astaxanthin in snow algae and purpurogallin in glacial algae) protect chloroplasts and nuclei from damaging PAR and UV, and ice binding proteins (IBPs) and polyunsaturated fatty acids (PUFAs) reduce cell damage in subfreezing temperatures. Molecular phylogenies reveal that snow algae in the Chlamydomonas-Chloromonas complex have invaded the snow habitat at least twice, and some species are polyphyletic. Snow and glacial algae reduce albedo, accelerate the melt of snowpacks and glaciers, and are used to monitor climate change. Selected strains of these algae have potential for producing food or fuel products.
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Affiliation(s)
- Ronald W. Hoham
- Department of BiologyColgate UniversityHamiltonNew York13346USA
| | - Daniel Remias
- School of EngineeringUniversity of Applied Sciences Upper AustriaWels4600Austria
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24
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Hartmann A, Glaser K, Holzinger A, Ganzera M, Karsten U. Klebsormidin A and B, Two New UV-Sunscreen Compounds in Green Microalgal Interfilum and Klebsormidium Species (Streptophyta) From Terrestrial Habitats. Front Microbiol 2020; 11:499. [PMID: 32292396 PMCID: PMC7118736 DOI: 10.3389/fmicb.2020.00499] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/09/2020] [Indexed: 01/16/2023] Open
Abstract
The terrestrial green algal members of the genera Interfilum and Klebsormidium (Klebsormidiophyceae, Streptophyta) are found in biological soil crusts of extreme habitats around the world where they are regularly exposed, among other abiotic stress factors, to high levels of ultraviolet radiation (UVR). As a consequence those species synthesize and accumulate either one or two mycosporine-like amino acids (MAAs), but with a missing structural elucidation up to now. Therefore, in the present study both MAAs were chemically isolated and structurally elucidated. The two new compounds exhibit absorption maxima of 324 nm. MAA 1 has a molecular weight of 467 and MAA 2 of 305, and the latter (MAA 2) was identified as N-(4,5-dihydroxy-5-(hydroxymethyl)-2-methoxy-3-oxocyclohex-1-en-1-yl)-N-methylserine using one- and two-dimensional 1H and 13C-NMR spectroscopy. MAA 1 contains an additional sugar moiety. As trivial names for these two novel MAAs we suggest klebsormidin A and klebsormidin B. Different species from all previously described phylogenetic clades of Klebsormidiophyceae were chemically screened for their MAA composition in aqueous extracts using RP-HPLC and LC-MS. The novel klebsormidin A was present throughout all clades and hence could be suitable as a chemotaxonomic marker. Additionally, controlled UVR-exposure experiments with all investigated species showed that MAA biosynthesis and intracellular enrichment is strongly induced by short wavelengths, supporting the function of these compounds as natural UV-sunscreen as well as explaining the cosmopolitan distribution and ecological success of Interfilum and Klebsormidium in terrestrial habitats.
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Affiliation(s)
- Anja Hartmann
- Department of Pharmacognosy, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria
| | - Karin Glaser
- Institute of Biological Sciences, University of Rostock, Rostock, Germany
| | | | - Markus Ganzera
- Department of Pharmacognosy, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria
| | - Ulf Karsten
- Institute of Biological Sciences, University of Rostock, Rostock, Germany
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25
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Glacier algae foster ice-albedo feedback in the European Alps. Sci Rep 2020; 10:4739. [PMID: 32179790 PMCID: PMC7075879 DOI: 10.1038/s41598-020-61762-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/18/2020] [Indexed: 01/25/2023] Open
Abstract
The melting of glaciers and ice sheets is nowadays considered a symbol of climate change. Many complex mechanisms are involved in the melting of ice, and, among these processes, surface darkening due to organic material on bare ice has recently received attention from the scientific community. The presence of microbes on glaciers has been shown to decrease the albedo of ice and promote melting. Despite several studies from the Himalaya, Greenland, Andes, and Alaska, no quantitative studies have yet been conducted in the European Alps. In this paper, we made use of DNA sequencing, microscopy and field spectroscopy to describe the nature of glacier algae found at a glacier (Vadret da Morteratsch) of the European Alps and to evaluate their effect on the ice-albedo feedback. Among different algal species identified in the samples, we found a remarkable abundance of Ancylonema nordenskioeldii, a species that has never previously been quantitatively documented in the Alps and that dominates algal blooms on the Greenland Ice Sheet. Our results show that, at the end of the ablation season, the concentration of Ancylonema nordenskioeldii on the glacier surface is higher than that of other algal species (i.e. Mesotaenium berggrenii). Using field spectroscopy data, we identified a significant correlation between a reflectance ratio (750 nm/650 nm) and the algae concentration. This reflectance ratio could be useful for future mapping of glacier algae from remote sensing data exploiting band 6 (740 nm) and band 4 (665 nm) of the MultiSpectral Instrument (MSI) on board Sentinel-2 satellite. Here we show that the biological darkening of glaciers (i.e. the bioalbedo feedback) is also occurring in the European Alps, and thus it is a global process that must be taken into account when considering the positive feedback mechanisms related to glacier melting.
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26
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Abstract
Processes that darken the surface of the Greenland Ice Sheet (GrIS) enhance energy absorption and accelerate melt, with consequences for global sea-level rise. Here, we demonstrate how summer blooms of “glacier algae” darken the ice surface, significantly impacting the physical integrity of the environment. We identify and quantify the energy regulation mechanisms employed by glacier algae to balance their requirements for photosynthesis and growth with the extreme light and temperature regime of the GrIS, demonstrating how these mechanisms are optimized to darken and melt the ice surface. Our findings are critical for the incorporation of biological feedbacks into predictive models of GrIS surface runoff and provide unique insight into how photoautotrophic life excels within icy environments. Blooms of Zygnematophycean “glacier algae” lower the bare ice albedo of the Greenland Ice Sheet (GrIS), amplifying summer energy absorption at the ice surface and enhancing meltwater runoff from the largest cryospheric contributor to contemporary sea-level rise. Here, we provide a step change in current understanding of algal-driven ice sheet darkening through quantification of the photophysiological mechanisms that allow glacier algae to thrive on and darken the bare ice surface. Significant secondary phenolic pigmentation (11 times the cellular content of chlorophyll a) enables glacier algae to tolerate extreme irradiance (up to ∼4,000 µmol photons⋅m−2⋅s−1) while simultaneously repurposing captured ultraviolet and short-wave radiation for melt generation. Total cellular energy absorption is increased 50-fold by phenolic pigmentation, while glacier algal chloroplasts positioned beneath shading pigments remain low-light–adapted (Ek ∼46 µmol photons⋅m−2⋅s−1) and dependent upon typical nonphotochemical quenching mechanisms for photoregulation. On the GrIS, glacier algae direct only ∼1 to 2.4% of incident energy to photochemistry versus 48 to 65% to ice surface melting, contributing an additional ∼1.86 cm water equivalent surface melt per day in patches of high algal abundance (∼104 cells⋅mL−1). At the regional scale, surface darkening is driven by the direct and indirect impacts of glacier algae on ice albedo, with a significant negative relationship between broadband albedo (Moderate Resolution Imaging Spectroradiometer [MODIS]) and glacier algal biomass (R2 = 0.75, n = 149), indicating that up to 75% of the variability in albedo across the southwestern GrIS may be attributable to the presence of glacier algae.
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27
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Barcytė D, Pilátová J, Mojzeš P, Nedbalová L. The Arctic Cylindrocystis (Zygnematophyceae, Streptophyta) Green Algae are Genetically and Morphologically Diverse and Exhibit Effective Accumulation of Polyphosphate. JOURNAL OF PHYCOLOGY 2020; 56:217-232. [PMID: 31610035 DOI: 10.1111/jpy.12931] [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: 05/30/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
The green algal genus Cylindrocystis is widespread in various types of environments, including extreme habitats. However, very little is known about its diversity, especially in polar regions. In the present study, we isolated seven new Cylindrocystis-like strains from terrestrial and freshwater habitats in Svalbard (High Arctic). We aimed to compare the new isolates on a molecular (rbcL and 18S rDNA), morphological (light and confocal laser scanning microscopy), and cytological (Raman microscopy) basis. Our results demonstrated that the Arctic Cylindrocystis were not of a monophyletic origin and that the studied strains clustered within two clades (tentatively named the soil and freshwater/glacier clades) and four separate lineages. Morphological data (cell size, shape, and chloroplast morphology) supported the presence of several distinct taxa among the new isolates. Moreover, the results showed that the Arctic Cylindrocystis strains were closely related to strains originating from the temperate zone, indicating high ecological versatility and successful long-distance dispersal of the genus. Large amounts of inorganic polyphosphate (polyP) grains were detected within the chloroplasts of the cultured Arctic Cylindrocystis strains, suggesting effective luxury uptake of phosphorus. Additionally, various intracellular structures were identified using Raman microscopy and cytochemical and fluorescent staining. This study represents the first attempt to combine molecular, morphological, ecological, and biogeographical data for Arctic Cylindrocystis. Our novel cytological observations partially explain the success of Cylindrocystis-like microalgae in polar regions.
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Affiliation(s)
- Dovilė Barcytė
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Prague 2, CZ-128 44, Czech Republic
| | - Jana Pilátová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, Prague 2, CZ-128 44, Czech Republic
| | - Peter Mojzeš
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague 2, CZ-121 16, Czech Republic
| | - Linda Nedbalová
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Prague 2, CZ-128 44, Czech Republic
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28
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Perseorangin: A natural pigment from avocado (Persea americana) seed. Food Chem 2019; 293:15-22. [DOI: 10.1016/j.foodchem.2019.04.064] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 04/15/2019] [Accepted: 04/17/2019] [Indexed: 11/23/2022]
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29
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Nicholes MJ, Williamson CJ, Tranter M, Holland A, Poniecka E, Yallop ML, Anesio A. Bacterial Dynamics in Supraglacial Habitats of the Greenland Ice Sheet. Front Microbiol 2019; 10:1366. [PMID: 31333595 PMCID: PMC6616251 DOI: 10.3389/fmicb.2019.01366] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/31/2019] [Indexed: 11/13/2022] Open
Abstract
Current research into bacterial dynamics on the Greenland Ice Sheet (GrIS) is biased toward cryoconite holes, despite this habitat covering less than 8% of the ablation (melt) zone surface. In contrast, the expansive surface ice, which supports wide-spread Streptophyte micro-algal blooms thought to enhance surface melt, has been relatively neglected. This study aims to understand variability in bacterial abundance and production across an ablation season on the GrIS, in relation to micro-algal bloom dynamics. Bacterial abundance reached 3.3 ± 0.3 × 105 cells ml−1 in surface ice and was significantly linearly related to algal abundances during the middle and late ablation periods (R2 = 0.62, p < 0.05; R2 = 0.78, p < 0.001). Bacterial production (BP) of 0.03–0.6 μg C L−1 h−1 was observed in surface ice and increased in concert with glacier algal abundances, indicating that heterotrophic bacteria consume algal-derived dissolved organic carbon. However, BP remained at least 28 times lower than net primary production, indicating inefficient carbon cycling by heterotrophic bacteria and net accumulation of carbon in surface ice throughout the ablation season. Across the supraglacial environment, cryoconite sediment BP was at least four times greater than surface ice, confirming that cryoconite holes are the true “hot spots” of heterotrophic bacterial activity.
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Affiliation(s)
- Miranda Jane Nicholes
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Christopher James Williamson
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom.,School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Martyn Tranter
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Alexandra Holland
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Ewa Poniecka
- School of Earth and Ocean Sciences, Cardiff University, Cardiff, United Kingdom
| | - Marian Louise Yallop
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom.,School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | | | - Alexandre Anesio
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom.,Department of Environmental Science, Aarhus University, Roskilde, Denmark
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30
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Williamson CJ, Cameron KA, Cook JM, Zarsky JD, Stibal M, Edwards A. Glacier Algae: A Dark Past and a Darker Future. Front Microbiol 2019; 10:524. [PMID: 31019491 PMCID: PMC6458304 DOI: 10.3389/fmicb.2019.00524] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/28/2019] [Indexed: 11/13/2022] Open
Abstract
"Glacier algae" grow on melting glacier and ice sheet surfaces across the cryosphere, causing the ice to absorb more solar energy and consequently melt faster, while also turning over carbon and nutrients. This makes glacier algal assemblages, which are typically dominated by just three main species, a potentially important yet under-researched component of the global biosphere, carbon, and water cycles. This review synthesizes current knowledge on glacier algae phylogenetics, physiology, and ecology. We discuss their significance for the evolution of early land plants and highlight their impacts on the physical and chemical supraglacial environment including their role as drivers of positive feedbacks to climate warming, thereby demonstrating their influence on Earth's past and future. Four complementary research priorities are identified, which will facilitate broad advances in glacier algae research, including establishment of reliable culture collections, sequencing of glacier algae genomes, development of diagnostic biosignatures for remote sensing, and improved predictive modeling of glacier algae biological-albedo effects.
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Affiliation(s)
- Christopher J Williamson
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Karen A Cameron
- Institute of Biological, Environmental & Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Joseph M Cook
- Department of Geography, The University of Sheffield, Sheffield, United Kingdom
| | - Jakub D Zarsky
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Marek Stibal
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Arwyn Edwards
- Institute of Biological, Environmental & Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
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31
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Perini L, Gostinčar C, Anesio AM, Williamson C, Tranter M, Gunde-Cimerman N. Darkening of the Greenland Ice Sheet: Fungal Abundance and Diversity Are Associated With Algal Bloom. Front Microbiol 2019; 10:557. [PMID: 30949152 PMCID: PMC6437116 DOI: 10.3389/fmicb.2019.00557] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 03/04/2019] [Indexed: 01/16/2023] Open
Abstract
Recent studies have highlighted the importance of ice-algal blooms in driving darkening and therefore surface melt of the Greenland Ice Sheet (GrIS). However, the contribution of fungal and bacterial communities to this microbially driven albedo reduction remains unconstrained. To address this significant knowledge gap, fungi were isolated from key GrIS surface habitats (surface ice containing varying abundance of ice algae, supraglacial water, cryoconite holes, and snow), and a combination of cultivation and sequencing methods utilized to characterize the algal-associated fungal and bacterial diversity and abundance. Six hundred and ninety-seven taxa of fungi were obtained by amplicon sequencing and more than 200 fungal cultures belonging to 46 different species were isolated through cultivation approaches. Basidiomycota dominated in surface ice and water samples, and Ascomycota in snow samples. Amplicon sequencing revealed that bacteria were characterized by a higher diversity (883 taxa detected). Results from cultivation as well as ergosterol analyses suggested that surface ice dominated by ice algae and cryoconite holes supported the highest fungal biomass (104-105 CFU/100 ml) and that many fungal taxa recognized as endophytes and plant pathogens were associated with dark ice characterized by a high abundance of ice algae. This paper significantly advances this field of research by investigating for the first time the fungal abundance and diversity associated with algal blooms causing the darkening of the GrIS. There is a strong association between the abundance and diversity of fungal species and the blooming of algae on the surface ice of the Greenland Ice Sheet.
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Affiliation(s)
- Laura Perini
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Alexandre Magno Anesio
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | - Christopher Williamson
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Martyn Tranter
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Nina Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
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32
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Dial RJ, Ganey GQ, Skiles SM. What color should glacier algae be? An ecological role for red carbon in the cryosphere. FEMS Microbiol Ecol 2019; 94:4810544. [PMID: 29346532 DOI: 10.1093/femsec/fiy007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 01/12/2018] [Indexed: 11/13/2022] Open
Abstract
Red-colored secondary pigments in glacier algae play an adaptive role in melting snow and ice. We advance this hypothesis using a model of color-based absorption of irradiance, an experiment with colored particles in snow, and the natural history of glacier algae. Carotenoids and phenols-astaxanthin in snow-algae and purpurogallin in ice-algae-shield photosynthetic apparatus by absorbing overabundant visible wavelengths, then dissipating the excess radiant energy as heat. This heat melts proximal ice crystals, providing liquid-water in a 0°C environment and freeing up nutrients bound in frozen water. We show that purple-colored particles transfer 87%-89% of solar energy absorbed by black particles. However, red-colored particles transfer nearly as much (85%-87%) by absorbing peak solar wavelengths and reflecting the visible wavelengths most absorbed by nearby ice and snow crystals; this latter process may reduce potential cellular overheating when snow insulates cells. Blue and green particles transfer only 80%-82% of black particle absorption. In the experiment, red-colored particles melted 87% as much snow as black particles, while blue particles melted 77%. Green-colored snow-algae naturally occupy saturated snow where water is non-limiting; red-colored snow-algae occupy drier, water-limited snow. In addition to increasing melt, we suggest that esterified astaxanthin in snow-alga cells increases hydrophobicity to remain surficial.
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Affiliation(s)
- Roman J Dial
- Institute of Culture and Environment, Alaska Pacific University, 4101 University Drive, Anchorage, AK 99508, USA
| | - Gerard Q Ganey
- Institute of Culture and Environment, Alaska Pacific University, 4101 University Drive, Anchorage, AK 99508, USA
| | - S McKenzie Skiles
- Department of Geography, University of Utah, 332 S 1400 E, Salt Lake City, UT 84112, USA
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33
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Williamson CJ, Anesio AM, Cook J, Tedstone A, Poniecka E, Holland A, Fagan D, Tranter M, Yallop ML. Ice algal bloom development on the surface of the Greenland Ice Sheet. FEMS Microbiol Ecol 2019; 94:4850643. [PMID: 29444265 PMCID: PMC6018781 DOI: 10.1093/femsec/fiy025] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/07/2018] [Indexed: 11/13/2022] Open
Abstract
It is fundamental to understand the development of Zygnematophycean (Streptophyte) micro-algal blooms within Greenland Ice Sheet (GrIS) supraglacial environments, given their potential to significantly impact both physical (melt) and chemical (carbon and nutrient cycling) surface characteristics. Here, we report on a space-for-time assessment of a GrIS ice algal bloom, achieved by sampling an ∼85 km transect spanning the south-western GrIS bare ice zone during the 2016 ablation season. Cell abundances ranged from 0 to 1.6 × 104 cells ml-1, with algal biomass demonstrated to increase in surface ice with time since snow line retreat (R2 = 0.73, P < 0.05). A suite of light harvesting and photo-protective pigments were quantified across transects (chlorophylls, carotenoids and phenols) and shown to increase in concert with algal biomass. Ice algal communities drove net autotrophy of surface ice, with maximal rates of net production averaging 0.52 ± 0.04 mg C l-1 d-1, and a total accumulation of 1.306 Gg C (15.82 ± 8.14 kg C km-2) predicted for the 2016 ablation season across an 8.24 × 104 km2 region of the GrIS. By advancing our understanding of ice algal bloom development, this study marks an important step toward projecting bloom occurrence and impacts into the future.
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Affiliation(s)
- C J Williamson
- Bristol Glaciology Centre, University of Bristol,12 Berkely Square, Bristol, BS8 1SS, UK.,School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - A M Anesio
- Bristol Glaciology Centre, University of Bristol,12 Berkely Square, Bristol, BS8 1SS, UK
| | - J Cook
- Department of Geography, The University of Sheffield, Sheffield, S10 2TN, UK
| | - A Tedstone
- Bristol Glaciology Centre, University of Bristol,12 Berkely Square, Bristol, BS8 1SS, UK
| | - E Poniecka
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - A Holland
- Bristol Glaciology Centre, University of Bristol,12 Berkely Square, Bristol, BS8 1SS, UK
| | - D Fagan
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - M Tranter
- Bristol Glaciology Centre, University of Bristol,12 Berkely Square, Bristol, BS8 1SS, UK
| | - M L Yallop
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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34
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Maccario L, Carpenter SD, Deming JW, Vogel TM, Larose C. Sources and selection of snow-specific microbial communities in a Greenlandic sea ice snow cover. Sci Rep 2019; 9:2290. [PMID: 30783153 PMCID: PMC6381142 DOI: 10.1038/s41598-019-38744-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 12/14/2018] [Indexed: 11/09/2022] Open
Abstract
Sea ice and its snow cover are critical for global processes including climate regulation and biogeochemical cycles. Despite an increase in studies focused on snow microorganisms, the ecology of snow inhabitants remains unclear. In this study, we investigated sources and selection of a snowpack-specific microbial community by comparing metagenomes from samples collected in a Greenlandic fjord within a vertical profile including atmosphere, snowpack with four distinct layers of snow, sea ice brine and seawater. Microbial communities in all snow layers derived from mixed sources, both marine and terrestrial, and were more similar to atmospheric communities than to sea ice or seawater communities. The surface snow metagenomes were characterized by the occurrence of genes involved in photochemical stress resistance, primary production and metabolism of diverse carbon sources. The basal saline snow layer that was in direct contact with the sea ice surface harbored a higher abundance of cells than the overlying snow layers, with a predominance of Alteromonadales and a higher relative abundance of marine representatives. However, the overall taxonomic structure of the saline layer was more similar to that of other snow layers and the atmosphere than to underlying sea ice and seawater. The expulsion of relatively nutrient-rich sea ice brine into basal snow might have stimulated the growth of copiotrophic psychro- and halotolerant snow members. Our study indicates that the size, composition and function of snowpack microbial communities over sea ice were influenced primarily by atmospheric deposition and inflow of sea ice brine and that they form a snow-specific assemblage reflecting the particular environmental conditions of the snowpack habitat.
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Affiliation(s)
- Lorrie Maccario
- Environmental Microbial Genomics, Laboratoire Ampère, CNRS, École Centrale de Lyon, Écully, France.
- Microbiology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | | | - Jody W Deming
- School of Oceanography, University of Washington, Seattle, USA
| | - Timothy M Vogel
- Environmental Microbial Genomics, Laboratoire Ampère, CNRS, École Centrale de Lyon, Écully, France
| | - Catherine Larose
- Environmental Microbial Genomics, Laboratoire Ampère, CNRS, École Centrale de Lyon, Écully, France
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35
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O'Neal SW, Hoover AM. Comparison of UVB effects on growth and induction of UVB screening compounds in isolates of metaphytic algae from temperate zone streams and ponds. JOURNAL OF PHYCOLOGY 2018; 54:818-828. [PMID: 30229900 DOI: 10.1111/jpy.12786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/18/2018] [Indexed: 06/08/2023]
Abstract
Filaments in the surface layers of metaphytic mats are exposed to high photon flux densities of PAR and UVBR. We investigated the effect of UVBR exposure on growth of eight isolates of common metaphytic algae (Cladophora, Mougeotia, Oedogonium, Pithophora, Spirogyra, and Zygnema) acclimated to either high or low PAR levels prior to UVBR exposure. All isolates acclimated to low PAR exhibited significant reductions in growth rate caused by the UVBR exposure (P < 0.05). Acclimation to high PAR resulted in seven of the isolates being more tolerant of the UVB exposure. The two Zygnema isolates exhibited the most pronounced effect of high PAR acclimation with growth rates of UVB exposed treatments being equal to that of controls (P > 0.05). High PAR acclimation also protected chlorophyll a levels in the Zygnema isolates. Absorption of UVB by methanol extracts increased 322%-381% for the two Zygnema isolates when high PAR acclimated. The broad absorption peak at 270 nm suggests that phenolic compounds were responsible. Previous studies have shown that Zygnema isolates from extreme environments tolerate UVBR and contain UVB screening compounds, but our results extend these adaptions to Zygnema from typical temperate zone habitats. Although none of the other metaphytic algae produced UVB absorbing compounds, they all exhibited higher growth rates under UVBR exposure following high PAR acclimation. This suggests that the algae evaluated have inducible defenses against UVBR exposure that coupled with their mat structure would provide an adaption to the challenging light environment in shallow-water habitats.
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Affiliation(s)
- Steven W O'Neal
- Department of Biological Sciences, Southwestern Oklahoma State University, 100 Campus Drive, Weatherford, Oklahoma, 73096, USA
| | - Angie M Hoover
- Division of Coastal Sciences Study, Gulf Coast Research Laboratory, 703 East Beach Drive, Ocean Springs, Mississippi, 39564, USA
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Holzinger A, Albert A, Aigner S, Uhl J, Schmitt-Kopplin P, Trumhová K, Pichrtová M. Arctic, Antarctic, and temperate green algae Zygnema spp. under UV-B stress: vegetative cells perform better than pre-akinetes. PROTOPLASMA 2018; 255:1239-1252. [PMID: 29470709 PMCID: PMC5994220 DOI: 10.1007/s00709-018-1225-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/08/2018] [Indexed: 05/13/2023]
Abstract
Species of Zygnema form macroscopically visible mats in polar and temperate terrestrial habitats, where they are exposed to environmental stresses. Three previously characterized isolates (Arctic Zygnema sp. B, Antarctic Zygnema sp. C, and temperate Zygnema sp. S) were tested for their tolerance to experimental UV radiation. Samples of young vegetative cells (1 month old) and pre-akinetes (6 months old) were exposed to photosynthetically active radiation (PAR, 400-700 nm, 400 μmol photons m-2 s-1) in combination with experimental UV-A (315-400 nm, 5.7 W m-2, no UV-B), designated as PA, or UV-A (10.1 W m-2) + UV-B (280-315 nm, 1.0 W m-2), designated as PAB. The experimental period lasted for 74 h; the radiation period was 16 h PAR/UV-A per day, or with additional UV-B for 14 h per day. The effective quantum yield, generally lower in pre-akinetes, was mostly reduced during the UV treatment, and recovery was significantly higher in young vegetative cells vs. pre-akinetes during the experiment. Analysis of the deepoxidation state of the xanthophyll-cycle pigments revealed a statistically significant (p < 0.05) increase in Zygnema spp. C and S. The content of UV-absorbing phenolic compounds was significantly higher (p < 0.05) in young vegetative cells compared to pre-akinetes. In young vegetative Zygnema sp. S, these phenolic compounds significantly increased (p < 0.05) upon PA and PAB. Transmission electron microscopy showed an intact ultrastructure with massive starch accumulations at the pyrenoids under PA and PAB. A possible increase in electron-dense bodies in PAB-treated cells and the occurrence of cubic membranes in the chloroplasts are likely protection strategies. Metabolite profiling by non-targeted RP-UHPLC-qToF-MS allowed a clear separation of the strains, but could not detect changes due to the PA and PAB treatments. Six hundred seventeen distinct molecular masses were detected, of which around 200 could be annotated from databases. These results indicate that young vegetative cells can adapt better to the experimental UV-B stress than pre-akinetes.
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Affiliation(s)
- Andreas Holzinger
- Department of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria.
| | - Andreas Albert
- Research Unit Environmental Simulation, Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt GmbH, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany
| | - Siegfried Aigner
- Department of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Jenny Uhl
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt GmbH, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany
| | - Philippe Schmitt-Kopplin
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt GmbH, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany
| | - Kateřina Trumhová
- Faculty of Science, Department of Botany, Charles University, Benátská 2, 128 01, Prague, Czech Republic
| | - Martina Pichrtová
- Faculty of Science, Department of Botany, Charles University, Benátská 2, 128 01, Prague, Czech Republic
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37
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Barcytė D, Hodač L, Nedbalová L, Elster J. Chloromonas svalbardensis n. sp. with Insights into the Phylogroup Chloromonadinia (Chlorophyceae). J Eukaryot Microbiol 2018; 65:882-892. [PMID: 29752887 DOI: 10.1111/jeu.12633] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/24/2018] [Accepted: 05/02/2018] [Indexed: 11/29/2022]
Abstract
The traditional green algal genus Chloromonas accommodates mesophilic, cold-tolerant and cold-adapted microorganisms. In this paper, we studied a new strain isolated from a wet hummock meadow in the High Arctic. We used morphological, ultrastructural and molecular data to assess the taxonomic position and phylogenetic relationships of the new isolate. The observed morphological features generally corresponded to the cold-tolerant Chloromonas characteristics. However, ellipsoidal or wide ellipsoidal vegetative cells, a massive parietal cup-shaped chloroplast with a number of continuously connected lobes, a thick cell wall, a prominent hemispherical papilla and the anterior position of an oblong or round eyespot distinguished the alga from all previously described Chloromonas species. Analyses of rbcL and 18S rRNA genes showed that the new strain formed an independent lineage within a clade containing mesophilic and psychrotolerant Chloromonas species. Comparisons of secondary structure models of a highly variable ITS2 rDNA marker supported a separate species identity of the new isolate. Considering the morphological and molecular differences from its relatives, a new psychrotolerant species, Chloromonas svalbardensis, is proposed. Further, our results demonstrated the paraphyletic origin of Chloromonas within Chloromonadinia with genetically, morphologically and ecologically well-defined clades. We discuss a scenario of a possible Chloromonas split and revision.
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Affiliation(s)
- Dovilė Barcytė
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 2 128 44, Prague, Czechia
| | - Ladislav Hodač
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-University of Göttingen, Untere Karspüle 2, 37073, Göttingen, Germany
| | - Linda Nedbalová
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 2 128 44, Prague, Czechia.,Institute of Botany, The Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czechia
| | - Josef Elster
- Institute of Botany, The Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czechia.,Centre for Polar Ecology, University of South Bohemia, Na Zlaté stoce 3, 370 05, České Budějovice, Czechia
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Lutz S, McCutcheon J, McQuaid JB, Benning LG. The diversity of ice algal communities on the Greenland Ice Sheet as revealed by oligotyping. Microb Genom 2018; 4. [PMID: 29547098 PMCID: PMC5885011 DOI: 10.1099/mgen.0.000159] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The Arctic is being disproportionally affected by climate change compared with other geographic locations, and is currently experiencing unprecedented melt rates. The Greenland Ice Sheet (GrIS) can be regarded as the largest supraglacial ecosystem on Earth, and ice algae are the dominant primary producers on bare ice surfaces throughout the course of a melt season. Ice-algal-derived pigments cause a darkening of the ice surface, which in turn decreases albedo and increases melt rates. The important role of ice algae in changing melt rates has only recently been recognized, and we currently know little about their community compositions and functions. Here, we present the first analysis of ice algal communities across a 100 km transect on the GrIS by high-throughput sequencing and subsequent oligotyping of the most abundant taxa. Our data reveal an extremely low algal diversity with Ancylonema nordenskiöldii and a Mesotaenium species being by far the dominant taxa at all sites. We employed an oligotyping approach and revealed a hidden diversity not detectable by conventional clustering of operational taxonomic units and taxonomic classification. Oligotypes of the dominant taxa exhibit a site-specific distribution, which may be linked to differences in temperatures and subsequently the extent of the melting. Our results help to better understand the distribution patterns of ice algal communities that play a crucial role in the GrIS ecosystem.
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Affiliation(s)
- Stefanie Lutz
- 1GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Jenine McCutcheon
- 2School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | - James B McQuaid
- 2School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | - Liane G Benning
- 1GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
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Abstract
Albedo—a primary control on surface melt—varies considerably across the Greenland Ice Sheet yet the specific surface types that comprise its dark zone remain unquantified. Here we use UAV imagery to attribute seven distinct surface types to observed albedo along a 25 km transect dissecting the western, ablating sector of the ice sheet. Our results demonstrate that distributed surface impurities—an admixture of dust, black carbon and pigmented algae—explain 73% of the observed spatial variability in albedo and are responsible for the dark zone itself. Crevassing and supraglacial water also drive albedo reduction but due to their limited extent, explain just 12 and 15% of the observed variability respectively. Cryoconite, concentrated in large holes or fluvial deposits, is the darkest surface type but accounts for <1% of the area and has minimal impact. We propose that the ongoing emergence and dispersal of distributed impurities, amplified by enhanced ablation and biological activity, will drive future expansion of Greenland's dark zone. The surface types that comprise the dark zone of the Greenland Ice Sheet, an area of bare ice with low albedo, are unknown. Here, the authors use UAV imagery to show that, during the melt-season, biologically active surface impurities are responsible for spatial albedo patterns and the dark zone itself.
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40
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Barcytė D, Hodač L, Nedbalová L, Elster J. Chloromonas arctica sp. nov., a psychrotolerant alga from snow in the High Arctic (Chlamydomonadales, Chlorophyta). Int J Syst Evol Microbiol 2018; 68:851-859. [PMID: 29458669 DOI: 10.1099/ijsem.0.002595] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
With the advent of molecular phylogenetic methods, it has become possible to assess the bioversity of snow algae more accurately. In this study, we focused on a morphological, ultrastructural and taxonomic description of a new Chloromonas-like alga isolated from snow in the High Arctic (Svalbard). Light and transmission electron microscopy revealed broad ellipsoidal or ellipsoidal-cylindrical, occasionally spherical cells with a chloroplast without a pyrenoid, an inconspicuous eyespot and a papilla. The size difference and the aforementioned morphological traits clearly distinguished the alga from its closest counterparts within the genus Chloromonas. Moreover, we were able to cultivate the alga at both 5 and 20 °C, revealing the psychrotolerant nature of the strain. Phylogenetic analyses of the plastid rbcL and nuclear 18S rRNA gene showed that the alga is nested within a clade containing a number of psychrotolerant strains within the Chloromonadinia phylogroup (Chlorophyceae). In the rbcL phylogeny, the alga formed an independent lineage, sister to the freshwater species Chloromonas paraserbinowii. Comparisons of secondary structure models of a highly variable ITS2 rDNA marker showed support for a distinct species identity for the new strain. The ITS2 secondary structure of the new isolate differed from the closest matches 'Chlamydomonas' gerloffii and Choloromonas reticulata by three and five compensatory base changes, respectively. Considering the morphological and molecular differences from its closest relatives, a new psychrotolerant species from the Arctic, Choromonas arctica sp. nov., is proposed.
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Affiliation(s)
- Dovilė Barcytė
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 44, Czech Republic
| | - Ladislav Hodač
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-University of Göttingen, Untere Karspüle 2, Göttingen, 37073, Germany
| | - Linda Nedbalová
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 44, Czech Republic.,The Czech Academy of Sciences, Institute of Botany, Dukelská 135, Třeboň, 379 82, Czech Republic
| | - Josef Elster
- The Czech Academy of Sciences, Institute of Botany, Dukelská 135, Třeboň, 379 82, Czech Republic.,Centre for Polar Ecology, University of South Bohemia, Na Zlaté stoce 3, České Budějovice, 370 05, Czech Republic
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41
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Anesio AM, Lutz S, Chrismas NAM, Benning LG. The microbiome of glaciers and ice sheets. NPJ Biofilms Microbiomes 2017; 3:10. [PMID: 28649411 PMCID: PMC5460203 DOI: 10.1038/s41522-017-0019-0] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/17/2017] [Accepted: 03/23/2017] [Indexed: 01/09/2023] Open
Abstract
Glaciers and ice sheets, like other biomes, occupy a significant area of the planet and harbour biological communities with distinct interactions and feedbacks with their physical and chemical environment. In the case of the glacial biome, the biological processes are dominated almost exclusively by microbial communities. Habitats on glaciers and ice sheets with enough liquid water to sustain microbial activity include snow, surface ice, cryoconite holes, englacial systems and the interface between ice and overridden rock/soil. There is a remarkable similarity between the different specific glacial habitats across glaciers and ice sheets worldwide, particularly regarding their main primary producers and ecosystem engineers. At the surface, cyanobacteria dominate the carbon production in aquatic/sediment systems such as cryoconite holes, while eukaryotic Zygnematales and Chlamydomonadales dominate ice surfaces and snow dynamics, respectively. Microbially driven chemolithotrophic processes associated with sulphur and iron cycle and C transformations in subglacial ecosystems provide the basis for chemical transformations at the rock interface under the ice that underpin an important mechanism for the delivery of nutrients to downstream ecosystems. In this review, we focus on the main ecosystem engineers of glaciers and ice sheets and how they interact with their chemical and physical environment. We then discuss the implications of this microbial activity on the icy microbiome to the biogeochemistry of downstream ecosystems.
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Affiliation(s)
- Alexandre M. Anesio
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS UK
| | - Stefanie Lutz
- GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
| | - Nathan A. M. Chrismas
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS UK
| | - Liane G. Benning
- GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
- Department of Earth Sciences, Free University of Berlin, 12249 Berlin, Germany
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42
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Barcytė D, Nedbalová L. Coccomyxa: a dominant planktic alga in two acid lakes of different origin. Extremophiles 2016; 21:245-257. [PMID: 27942983 DOI: 10.1007/s00792-016-0899-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 11/07/2016] [Indexed: 11/25/2022]
Abstract
The aim of this study was to reveal the taxonomic position and phylogenetic relationships of the dominant planktic algae in two acid metal-rich lakes of different origin (Hromnice Lake and Plešné Lake, Czech Republic) and to investigate their morphology and ultrastructure under natural and laboratory conditions. Phylogenetic analyses (18S rRNA and ITS-2) revealed that the strain isolated from Hromnice Lake belongs to the species Coccomyxa elongata, while Coccomyxa from Plešné Lake was described as a new species C. silvae-gabretae. It is the first evidence that representatives of this genus are capable of becoming the dominant primary producers in the extreme environment of acid lakes with an increased supply of phosphorus. There were clear differences in cell morphology under different growth conditions, revealing the high phenotypic plasticity of the strains. The ability to change the morphology may help the cells of Coccomyxa to survive harsh conditions in the aforementioned acid lakes.
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Affiliation(s)
- Dovilė Barcytė
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, Prague 2, 128 44, Czech Republic.
| | - Linda Nedbalová
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, Prague 2, 128 44, Czech Republic
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43
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Lutz S, Anesio AM, Edwards A, Benning LG. Linking microbial diversity and functionality of arctic glacial surface habitats. Environ Microbiol 2016; 19:551-565. [PMID: 27511455 DOI: 10.1111/1462-2920.13494] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 08/08/2016] [Indexed: 11/28/2022]
Abstract
Distinct microbial habitats on glacial surfaces are dominated by snow and ice algae, which are the critical players and the dominant primary colonisers and net producers during the melt season. Here for the first time we have evaluated the role of these algae in association with the full microbial community composition (i.e., algae, bacteria, archaea) in distinct surface habitats and on 12 glaciers and permanent snow fields in Svalbard and Arctic Sweden. We cross-correlated these data with the analyses of specific metabolites such as fatty acids and pigments, and a full suite of potential critical physico-chemical parameters including major and minor nutrients, and trace metals. It has been shown that correlations between single algal species, metabolites, and specific geochemical parameters can be used to unravel mixed metabolic signals in complex communities, further assign them to single species and infer their functionality. The data also clearly show that the production of metabolites in snow and ice algae is driven mainly by nitrogen and less so by phosphorus limitation. This is especially important for the synthesis of secondary carotenoids, which cause a darkening of glacial surfaces leading to a decrease in surface albedo and eventually higher melting rates.
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Affiliation(s)
- Stefanie Lutz
- GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany.,Cohen Laboratories, School of Earth & Environment, University of Leeds, Leeds, LS2 9JT, UK
| | - Alexandre M Anesio
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK
| | - Arwyn Edwards
- Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, SY23 3FL, UK.,Interdisciplinary Centre for Environmental Microbiology, Aberystwyth University, SY23 3FL, UK
| | - Liane G Benning
- GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany.,Cohen Laboratories, School of Earth & Environment, University of Leeds, Leeds, LS2 9JT, UK
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Herburger K, Remias D, Holzinger A. The green alga Zygogonium ericetorum (Zygnematophyceae, Charophyta) shows high iron and aluminium tolerance: protection mechanisms and photosynthetic performance. FEMS Microbiol Ecol 2016; 92:fiw103. [PMID: 27178434 PMCID: PMC4909054 DOI: 10.1093/femsec/fiw103] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 01/21/2016] [Accepted: 04/27/2016] [Indexed: 12/27/2022] Open
Abstract
Streptophyte green algae, ancestors of Embryophytes, occur frequently in terrestrial habitats being exposed to high light intensities, water scarcity and potentially toxic metal cations under acidic conditions. The filamentous Zygogonium ericetorum synthesizes a purple vacuolar ferrous pigment, which is lost after aplanospore formation. However, it is unknown whether this cellular reorganization also removes excessive iron from the protoplast and how Z. ericetorum copes with high concentrations of aluminium. Here we show that aplanospore formation shifts iron into the extracellular space of the algal filament. Upon germination of aplanospores, aluminium is bound in the parental cell wall. Both processes reduce iron and aluminium in unpigmented filaments. Comparison of the photosynthetic oxygen production in response to light and temperature gradients in two different Z. ericetorum strains from an Austrian alpine and a Scottish highland habitat revealed lower values in the latter strain. In contrast, the Scottish strain showed a higher optimum quantum yield of PSII during desiccation stress followed by rehydration. Furthermore, pigmented filaments of both strains exhibited a higher light and temperature dependent oxygen production when compared to the unpigmented phenotype. Our results demonstrate a high metal tolerance of Z. ericetorum, which is crucial for surviving in acidic terrestrial habitats.
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Affiliation(s)
- Klaus Herburger
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestraße 15, A-6020 Innsbruck, Austria
| | - Daniel Remias
- University of Applied Sciences Upper Austria, School of Engineering, Stelzhamerstraße 23, A-4600 Wels, Austria
| | - Andreas Holzinger
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestraße 15, A-6020 Innsbruck, Austria
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Lütz-Meindl U. Micrasterias as a Model System in Plant Cell Biology. FRONTIERS IN PLANT SCIENCE 2016; 7:999. [PMID: 27462330 PMCID: PMC4940373 DOI: 10.3389/fpls.2016.00999] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/24/2016] [Indexed: 05/18/2023]
Abstract
The unicellular freshwater alga Micrasterias denticulata is an exceptional organism due to its complex star-shaped, highly symmetric morphology and has thus attracted the interest of researchers for many decades. As a member of the Streptophyta, Micrasterias is not only genetically closely related to higher land plants but shares common features with them in many physiological and cell biological aspects. These facts, together with its considerable cell size of about 200 μm, its modest cultivation conditions and the uncomplicated accessibility particularly to any microscopic techniques, make Micrasterias a very well suited cell biological plant model system. The review focuses particularly on cell wall formation and composition, dictyosomal structure and function, cytoskeleton control of growth and morphogenesis as well as on ionic regulation and signal transduction. It has been also shown in the recent years that Micrasterias is a highly sensitive indicator for environmental stress impact such as heavy metals, high salinity, oxidative stress or starvation. Stress induced organelle degradation, autophagy, adaption and detoxification mechanisms have moved in the center of interest and have been investigated with modern microscopic techniques such as 3-D- and analytical electron microscopy as well as with biochemical, physiological and molecular approaches. This review is intended to summarize and discuss the most important results obtained in Micrasterias in the last 20 years and to compare the results to similar processes in higher plant cells.
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Affiliation(s)
- Ursula Lütz-Meindl
- Plant Physiology Division, Cell Biology Department, University of SalzburgSalzburg, Austria
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46
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Holzinger A, Allen MC, Deheyn DD. Hyperspectral imaging of snow algae and green algae from aeroterrestrial habitats. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 162:412-420. [PMID: 27442511 DOI: 10.1016/j.jphotobiol.2016.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/01/2016] [Accepted: 07/03/2016] [Indexed: 10/21/2022]
Abstract
Snow algae and green algae living in aeroterrestrial habitats are ideal objects to study adaptation to high light irradiation. Here, we used a detailed description of the spectral properties as a proxy for photo-acclimation/protection in snow algae (Chlamydomonas nivalis, Chlainomonas sp. and Chloromonas sp.) and charophyte green algae (Zygnema sp., Zygogonium ericetorum and Klebsormidium crenulatum). The hyperspectral microscopic mapping and imaging technique allowed us to acquire total absorption spectra of these microalgae in the waveband of 400-900nm. Particularly in Chlamydomonas nivalis and Chlainomonas sp., a high absorbance between 400-550nm was observed, due to naturally occurring secondary carotenoids; in Chloromonas sp. and in the charopyhte algae this high absorbance was missing, the latter being close relatives to land plants. To investigate if cellular water loss has an influence on the spectral properties, the cells were plasmolysed in sorbitol or desiccated at ambient air. While in snow algae, these treatments did hardly change the spectral properties, in the charopyhte algae the condensation of the cytoplasm and plastids increased the absorbance in the lower waveband of 400-500nm. These changes might be ecologically relevant and photoprotective, as aeroterrestrial algae are naturally exposed to occasional water limitation, leading to desiccation, which are conditions usually occurring together with higher irradiation.
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Affiliation(s)
- Andreas Holzinger
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria.
| | - Michael C Allen
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0202, USA
| | - Dimitri D Deheyn
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0202, USA.
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47
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Holzinger A, Pichrtová M. Abiotic Stress Tolerance of Charophyte Green Algae: New Challenges for Omics Techniques. FRONTIERS IN PLANT SCIENCE 2016; 7:678. [PMID: 27242877 PMCID: PMC4873514 DOI: 10.3389/fpls.2016.00678] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/02/2016] [Indexed: 05/20/2023]
Abstract
Charophyte green algae are a paraphyletic group of freshwater and terrestrial green algae, comprising the classes of Chlorokybophyceae, Coleochaetophyceae, Klebsormidiophyceae, Zygnematophyceae, Mesostigmatophyceae, and Charo- phyceae. Zygnematophyceae (Conjugating green algae) are considered to be closest algal relatives to land plants (Embryophyta). Therefore, they are ideal model organisms for studying stress tolerance mechanisms connected with transition to land, one of the most important events in plant evolution and the Earth's history. In Zygnematophyceae, but also in Coleochaetophyceae, Chlorokybophyceae, and Klebsormidiophyceae terrestrial members are found which are frequently exposed to naturally occurring abiotic stress scenarios like desiccation, freezing and high photosynthetic active (PAR) as well as ultraviolet (UV) irradiation. Here, we summarize current knowledge about various stress tolerance mechanisms including insight provided by pioneer transcriptomic and proteomic studies. While formation of dormant spores is a typical strategy of freshwater classes, true terrestrial groups are stress tolerant in vegetative state. Aggregation of cells, flexible cell walls, mucilage production and accumulation of osmotically active compounds are the most common desiccation tolerance strategies. In addition, high photophysiological plasticity and accumulation of UV-screening compounds are important protective mechanisms in conditions with high irradiation. Now a shift from classical chemical analysis to next-generation genome sequencing, gene reconstruction and annotation, genome-scale molecular analysis using omics technologies followed by computer-assisted analysis will give new insights in a systems biology approach. For example, changes in transcriptome and role of phytohormone signaling in Klebsormidium during desiccation were recently described. Application of these modern approaches will deeply enhance our understanding of stress reactions in an unbiased non-targeted view in an evolutionary context.
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Affiliation(s)
- Andreas Holzinger
- Unit of Functional Plant Biology, Institute of Botany, University of Innsbruck, InnsbruckAustria
- *Correspondence: Andreas Holzinger,
| | - Martina Pichrtová
- Unit of Functional Plant Biology, Institute of Botany, University of Innsbruck, InnsbruckAustria
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Maccario L, Sanguino L, Vogel TM, Larose C. Snow and ice ecosystems: not so extreme. Res Microbiol 2015; 166:782-95. [PMID: 26408452 DOI: 10.1016/j.resmic.2015.09.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 09/02/2015] [Accepted: 09/11/2015] [Indexed: 11/18/2022]
Abstract
Snow and ice environments cover up to 21% of the Earth's surface. They have been regarded as extreme environments because of their low temperatures, high UV irradiation, low nutrients and low water availability, and thus, their microbial activity has not been considered relevant from a global microbial ecology viewpoint. In this review, we focus on why snow and ice habitats might not be extreme from a microbiological perspective. Microorganisms interact closely with the abiotic conditions imposed by snow and ice habitats by having diverse adaptations, that include genetic resistance mechanisms, to different types of stresses in addition to inhabiting various niches where these potential stresses might be reduced. The microbial communities inhabiting snow and ice are not only abundant and taxonomically diverse, but complex in terms of their interactions. Altogether, snow and ice seem to be true ecosystems with a role in global biogeochemical cycles that has likely been underestimated. Future work should expand past resistance studies to understanding the function of these ecosystems.
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Affiliation(s)
- Lorrie Maccario
- Environmental Microbial Genomics, Laboratoire Ampère, CNRS UMR 5005, Université de Lyon, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully, France
| | - Laura Sanguino
- Environmental Microbial Genomics, Laboratoire Ampère, CNRS UMR 5005, Université de Lyon, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully, France
| | - Timothy M Vogel
- Environmental Microbial Genomics, Laboratoire Ampère, CNRS UMR 5005, Université de Lyon, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully, France
| | - Catherine Larose
- Environmental Microbial Genomics, Laboratoire Ampère, CNRS UMR 5005, Université de Lyon, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully, France.
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Herburger K, Lewis LA, Holzinger A. Photosynthetic efficiency, desiccation tolerance and ultrastructure in two phylogenetically distinct strains of alpine Zygnema sp. (Zygnematophyceae, Streptophyta): role of pre-akinete formation. PROTOPLASMA 2015; 252:571-89. [PMID: 25269628 PMCID: PMC4335129 DOI: 10.1007/s00709-014-0703-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/12/2014] [Indexed: 05/20/2023]
Abstract
Two newly isolated strains of green algae from alpine regions were compared physiologically at different culture ages (1, 6, 9 and 15 months). The strains of Zygnema sp. were from different altitudes ('Saalach' (S), 440 m above sea level (a.s.l.), SAG 2419 and 'Elmau-Alm' (E-A), 1,500 m a.s.l., SAG 2418). Phylogenetic analysis of rbcL sequences grouped the strains into different major subclades of the genus. The mean diameters of the cells were 23.2 μm (Zygnema S) and 18.7 μm (Zygnema E-A) but were reduced significantly with culture age. The photophysiological response between the strains differed significantly; Zygnema S had a maximal relative electron transport rate (rETR max) of 103.4 μmol electrons m(-2) s(-1), Zygnema E-A only 61.7 μmol electrons m(-2) s(-1), and decreased significantly with culture age. Both strains showed a low-light adaption and the absence of strong photoinhibition up to 2,000 μmol photons m(-2) s(-1). Photosynthetic oxygen production showed similar results (P max Zygnema S, 527.2 μmol O2 h(-1) mg(-1) chlorophyll (chl.) a, Zygnema E-A, 390.7 μmol O2 h(-1) mg(-1) chl. a); the temperature optimum was at 35 °C for Zygnema S and 30 °C for Zygnema E-A. Increasing culture age moreover leads to the formation of pre-akinetes, which accumulate storage products as revealed by light and transmission electron microscopy. Desiccation at 84 % relative air humidity (RH) lead to a reduction of the effective quantum yield of photosystem II (PSII) (ΔFv/Fm') to zero between 90 to 120 min (Zygnema S) and between 30 to 60 min (Zygnema E-A), depending on the culture age. A partial recovery of ΔFv/Fm' was only observed in older cultures. We conclude that pre-akinetes are crucial for the aeroterrestrial lifestyle of Zygnema.
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Affiliation(s)
- K. Herburger
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
| | - L. A. Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269-3043 USA
| | - A. Holzinger
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
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Uetake J, Tanaka S, Hara K, Tanabe Y, Samyn D, Motoyama H, Imura S, Kohshima S. Novel biogenic aggregation of moss gemmae on a disappearing African glacier. PLoS One 2014; 9:e112510. [PMID: 25401789 PMCID: PMC4234412 DOI: 10.1371/journal.pone.0112510] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 10/18/2014] [Indexed: 11/18/2022] Open
Abstract
Tropical regions are not well represented in glacier biology, yet many tropical glaciers are under threat of disappearance due to climate change. Here we report a novel biogenic aggregation at the terminus of a glacier in the Rwenzori Mountains, Uganda. The material was formed by uniseriate protonemal moss gemmae and protonema. Molecular analysis of five genetic markers determined the taxon as Ceratodon purpureus, a cosmopolitan species that is widespread in tropical to polar region. Given optimal growing temperatures of isolate is 20-30 °C, the cold glacier surface might seem unsuitable for this species. However, the cluster of protonema growth reached approximately 10 °C in daytime, suggesting that diurnal increase in temperature may contribute to the moss's ability to inhabit the glacier surface. The aggregation is also a habitat for microorganisms, and the disappearance of this glacier will lead to the loss of this unique ecosystem.
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Affiliation(s)
- Jun Uetake
- Transdisciplinary Research Integration Center, Minato-ku, Tokyo, Japan
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
- * E-mail:
| | - Sota Tanaka
- Faculty of Science, Chiba University, Chiba, Chiba, Japan
| | - Kosuke Hara
- Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Yukiko Tanabe
- Institute for Advanced Study, Waseda University, Shinjuku-ku, Tokyo, Japan
| | - Denis Samyn
- Department of Mechanical Engineering, Nagaoka University of Technology, Nagaoka, Nigata, Japan
| | | | - Satoshi Imura
- Faculty of Science, Chiba University, Chiba, Chiba, Japan
| | - Shiro Kohshima
- Wildlife Research Center, Kyoto University, Kyoto, Kyoto, Japan
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