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Güngör E, Savary J, Adema K, Dijkhuizen LW, Keilwagen J, Himmelbach A, Mascher M, Koppers N, Bräutigam A, Van Hove C, Riant O, Nierzwicki-Bauer S, Schluepmann H. The crane fly glycosylated triketide δ-lactone cornicinine elicits akinete differentiation of the cyanobiont in aquatic Azolla fern symbioses. Plant Cell Environ 2024. [PMID: 38600764 DOI: 10.1111/pce.14907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/02/2024] [Accepted: 03/22/2024] [Indexed: 04/12/2024]
Abstract
The restriction of plant-symbiont dinitrogen fixation by an insect semiochemical had not been previously described. Here we report on a glycosylated triketide δ-lactone from Nephrotoma cornicina crane flies, cornicinine, that causes chlorosis in the floating-fern symbioses from the genus Azolla. Only the glycosylated trans-A form of chemically synthesized cornicinine was active: 500 nM cornicinine in the growth medium turned all cyanobacterial filaments from Nostoc azollae inside the host leaf-cavities into akinetes typically secreting CTB-bacteriocins. Cornicinine further inhibited akinete germination in Azolla sporelings, precluding re-establishment of the symbiosis during sexual reproduction. It did not impact development of the plant Arabidopsis thaliana or several free-living cyanobacteria from the genera Anabaena or Nostoc but affected the fern host without cyanobiont. Fern-host mRNA sequencing from isolated leaf cavities confirmed high NH4-assimilation and proanthocyanidin biosynthesis in this trichome-rich tissue. After cornicinine treatment, it revealed activation of Cullin-RING ubiquitin-ligase-pathways, known to mediate metabolite signaling and plant elicitation consistent with the chlorosis phenotype, and increased JA-oxidase, sulfate transport and exosome formation. The work begins to uncover molecular mechanisms of cyanobiont differentiation in a seed-free plant symbiosis important for wetland ecology or circular crop-production today, that once caused massive CO2 draw-down during the Eocene geological past.
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Affiliation(s)
- Erbil Güngör
- Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Jérôme Savary
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Kelvin Adema
- Department of Biology, Utrecht University, Utrecht, The Netherlands
| | | | | | - Axel Himmelbach
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Seeland, Germany
| | - Martin Mascher
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Seeland, Germany
| | - Nils Koppers
- Computational Biology, Center for Biotechnology and Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Andrea Bräutigam
- Computational Biology, Center for Biotechnology and Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Charles Van Hove
- Emeritus Professor from the Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Olivier Riant
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
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Ahmed AAQ, McKay TJM. Environmental and ecological importance of bacterial extracellular vesicles (BEVs). Sci Total Environ 2024; 907:168098. [PMID: 37884154 DOI: 10.1016/j.scitotenv.2023.168098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/24/2023] [Accepted: 10/22/2023] [Indexed: 10/28/2023]
Abstract
Extracellular vesicles are unique structures released by the cells of all life forms. Bacterial extracellular vesicles (BEVs) were found in various ecosystems and natural habitats. They are associated with bacterial-bacterial interactions as well as host-bacterial interactions in the environment. Moreover, BEVs facilitate bacterial adaptation to a variety of environmental conditions. BEVs were found to be abundant in the environment, and therefore they can regulate a broad range of environmental processes. In the environment, BEVs can serve as tools for cell-to-cell interaction, secreting mechanism of unwanted materials, transportation, genetic materials exchange and storage, defense and protection, growth support, electron transfer, and cell-surface interplay regulation. Thus, BEVs have a great potential to be used in a variety of environmental applications such as serving as bioremediating reagents for environmental disaster mitigation as well as removing problematic biofilms and waste treatment. This research area needs to be investigated further to disclose the full environmental and ecological importance of BEVs as well as to investigate how to harness BEVs as effective tools in a variety of environmental applications.
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Affiliation(s)
- Abeer Ahmed Qaed Ahmed
- Department of Environmental Sciences, School of Ecological and Human Sustainability, College of Agriculture and Environmental Sciences, University of South Africa, P.O. Box 392, Florida, Johannesburg 1710, South Africa.
| | - Tracey Jill Morton McKay
- Department of Environmental Sciences, School of Ecological and Human Sustainability, College of Agriculture and Environmental Sciences, University of South Africa, P.O. Box 392, Florida, Johannesburg 1710, South Africa
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Flores E, Romanovicz DK, Nieves-Morión M, Foster RA, Villareal TA. Adaptation to an Intracellular Lifestyle by a Nitrogen-Fixing, Heterocyst-Forming Cyanobacterial Endosymbiont of a Diatom. Front Microbiol 2022; 13:799362. [PMID: 35369505 PMCID: PMC8969518 DOI: 10.3389/fmicb.2022.799362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/22/2022] [Indexed: 11/13/2022] Open
Abstract
The symbiosis between the diatom Hemiaulus hauckii and the heterocyst-forming cyanobacterium Richelia intracellularis makes an important contribution to new production in the world's oceans, but its study is limited by short-term survival in the laboratory. In this symbiosis, R. intracellularis fixes atmospheric dinitrogen in the heterocyst and provides H. hauckii with fixed nitrogen. Here, we conducted an electron microscopy study of H. hauckii and found that the filaments of the R. intracellularis symbiont, typically composed of one terminal heterocyst and three or four vegetative cells, are located in the diatom's cytoplasm not enclosed by a host membrane. A second prokaryotic cell was also detected in the cytoplasm of H. hauckii, but observations were infrequent. The heterocysts of R. intracellularis differ from those of free-living heterocyst-forming cyanobacteria in that the specific components of the heterocyst envelope seem to be located in the periplasmic space instead of outside the outer membrane. This specialized arrangement of the heterocyst envelope and a possible association of the cyanobacterium with oxygen-respiring mitochondria may be important for protection of the nitrogen-fixing enzyme, nitrogenase, from photosynthetically produced oxygen. The cell envelope of the vegetative cells of R. intracellularis contained numerous membrane vesicles that resemble the outer-inner membrane vesicles of Gram-negative bacteria. These vesicles can export cytoplasmic material from the bacterial cell and, therefore, may represent a vehicle for transfer of fixed nitrogen from R. intracellularis to the diatom's cytoplasm. The specific morphological features of R. intracellularis described here, together with its known streamlined genome, likely represent specific adaptations of this cyanobacterium to an intracellular lifestyle.
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Affiliation(s)
- Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC, Universidad de Sevilla, Seville, Spain
| | - Dwight K Romanovicz
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
| | - Mercedes Nieves-Morión
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC, Universidad de Sevilla, Seville, Spain
| | - Rachel A Foster
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Tracy A Villareal
- Department of Marine Science and Marine Science Institute, The University of Texas at Austin, Port Aransas, TX, United States
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Usui K, Yamamoto H, Oi T, Taniguchi M, Mori H, Fujita Y. Extracellular Vesicle-Mediated Secretion of Protochlorophyllide in the Cyanobacterium Leptolyngbya boryana. Plants 2022; 11:910. [PMID: 35406890 PMCID: PMC9003413 DOI: 10.3390/plants11070910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/19/2022] [Accepted: 03/25/2022] [Indexed: 11/17/2022]
Abstract
Protochlorophyllide (Pchlide) reduction in the late stage of chlorophyll a (Chl) biosynthesis is catalyzed by two enzymes: light-dependent Pchlide oxidoreductase (LPOR) and dark-operative Pchlide oxidoreductase (DPOR). The differential operation of LPOR and DPOR enables a stable supply of Chl in response to changes in light conditions and environmental oxygen levels. When a DPOR-deficient mutant (YFC2) of the cyanobacterium Leptolyngbya boryana is grown heterotrophically in the dark, Pchlide accumulates in the cells and is secreted into the culture medium. In this study, we demonstrated the extracellular vesicle-mediated secretion of Pchlide. Pchlide fractions were isolated from the culture medium using sucrose density gradient centrifugation. Mass spectrometry analysis revealed that the Pchlide fractions contained porin isoforms, TolC, and FG-GAP repeat-containing protein, which are localized in the outer membrane. Transmission electron microscopy revealed extracellular vesicle-like structures in the vicinity of YFC2 cells and the Pchlide fractions. These findings suggested that the Pchlide secretion is mediated by extracellular vesicles in dark-grown YFC2 cells.
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de Vries S, de Vries J. Evolutionary genomic insights into cyanobacterial symbioses in plants. Quant Plant Biol 2022; 3:e16. [PMID: 37077989 PMCID: PMC10095879 DOI: 10.1017/qpb.2022.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 05/03/2023]
Abstract
Photosynthesis, the ability to fix atmospheric carbon dioxide, was acquired by eukaryotes through symbiosis: the plastids of plants and algae resulted from a cyanobacterial symbiosis that commenced more than 1.5 billion years ago and has chartered a unique evolutionary path. This resulted in the evolutionary origin of plants and algae. Some extant land plants have recruited additional biochemical aid from symbiotic cyanobacteria; these plants associate with filamentous cyanobacteria that fix atmospheric nitrogen. Examples of such interactions can be found in select species from across all major lineages of land plants. The recent rise in genomic and transcriptomic data has provided new insights into the molecular foundation of these interactions. Furthermore, the hornwort Anthoceros has emerged as a model system for the molecular biology of cyanobacteria-plant interactions. Here, we review these developments driven by high-throughput data and pinpoint their power to yield general patterns across these diverse symbioses.
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Affiliation(s)
- Sophie de Vries
- Department of Applied Bioinformatics, Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
- Authors for correspondence: Sophie de Vries E-mail: Jan de Vries E-mail:
| | - Jan de Vries
- Department of Applied Bioinformatics, Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
- Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
- Campus Institute Data Science (CIDAS), University of Goettingen, Goettingen, Germany
- Authors for correspondence: Sophie de Vries E-mail: Jan de Vries E-mail:
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Jat SL, Suby SB, Parihar CM, Gambhir G, Kumar N, Rakshit S. Microbiome for sustainable agriculture: a review with special reference to the corn production system. Arch Microbiol 2021; 203:2771-2793. [PMID: 33884458 DOI: 10.1007/s00203-021-02320-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 10/21/2022]
Abstract
Microbial diversity formed by ages of evolution in soils plays an important role in sustainability of crop production by enriching soil and alleviating biotic and abiotic stresses. This diversity is as an essential part of the agro-ecosystems, which is being pushed to edges by pumping agrochemicals and constant soil disturbances. Consequently, efficiency of cropping system has been decreasing, aggravated further by the increased incidence of abiotic stresses due to changes in climatic patterns. Thus, the sustainability of agriculture is at stake. Understanding the microbiota inhabiting phyllosphere, endosphere, spermosphere, rhizosphere, and non-rhizosphere, and its utilization could be a sustainable crop production strategy. This review explores the available information on diversity of beneficial microbes in agricultural ecosystem and synthesizes their commercial uses in agriculture. Microbiota in agro-ecosystem works by nutrient acquisition, enhancing nutrient availability, water uptake, and amelioration of abiotic and abiotic stresses. External application of such beneficial microbiota or microbial consortia helps in boosting plant growth and provides resistance to drought, salinity, heavy metal, high-temperature and radiation stress in various crop plants. These have been instrumental in enhancing tolerance to diseases, insect pest and nematodes in various cropping system. However, studies on the microbiome in revolutionary production systems like conservation agriculture and protected cultivation, which use lesser agrochemicals, are limited and if exploited can provide valuable input in sustainable agriculture production.
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Affiliation(s)
- S L Jat
- ICAR-Indian Institute of Maize Research, Ludhiana, India.
| | - S B Suby
- ICAR-Indian Institute of Maize Research, Ludhiana, India
| | - C M Parihar
- ICAR-Indian Agricultural Research Institute, New Delhi, India
| | | | - Naveen Kumar
- ICAR-Indian Institute of Maize Research, Ludhiana, India
| | - Sujay Rakshit
- ICAR-Indian Institute of Maize Research, Ludhiana, India.
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ABRAHAM GERARD, JAISWAL PRANITA, SINGH YUDHVIR, YADAV RAVINDRAKUMAR, KUMAR RAVINDRA, MUDGAL VISHAL, SINGH PAWANKUMAR. Perspectives on the utilization of Azolla-Anabaena system as feed supplement. Indian J of Anim Sci 2021. [DOI: 10.56093/ijans.v90i9.109441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The nitrogen fixing aquatic pteridophyte Azolla is one of the fastest growing nitrogen-fixing plants and it is used as a potential source for high rate biomass production. Azolla has the ability to fix atmospheric nitrogen at cheaper and faster rates due to the presence of a symbiotic cyanobacterium Anabaena azollae. Therefore, the ability to fix atmospheric nitrogen is important from an agricultural perspective. However, Azolla is gaining popularity as feed supplement for cattle, poultry and fish. Further, the ease of cultivation and favourable nutrient composition make Azolla an important feed supplement. This review focuses on the perspectives of Azolla as feed supplement.
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Gunawardana D. An in silico Study of Two Transcription Factors Controlling Diazotrophic Fates of the Azolla Major Cyanobiont Trichormus azollae. Bioinform Biol Insights 2020; 14:1177932220977490. [PMID: 33402818 PMCID: PMC7747107 DOI: 10.1177/1177932220977490] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/01/2020] [Indexed: 11/17/2022] Open
Abstract
The cyanobiont Trichormus azollae lives symbiotically within fronds of the genus Azolla, and assimilates atmospheric nitrogen upon N-limitation, which earmarks this symbiosis to be a valuable biofertilizer in rice cultivation, among many other benefits that also include carbon sequestration. Therefore, studying the regulation of nitrogen fixation in Trichormus azollae is of great importance and benefit, especially the two topmost rungs of regulation, the NtcA and HetR transcription factors that are able to regulate the expression of myriads of downstream genes. Bioinformatics tools were used to zoom in on the NtcA and HetR transcription factors from Trichormus azollae to elaborate on what makes this particular cyanobiont different from other symbiotic as well as more distinct counterparts, in their commitment to nitrogen fixation. The utility of Azolla plants in tropical agriculture in particular merits the "top down N-regulation" by cyanobiont as a significant niche area of study, to make sense of superior N-fixing capabilities. The Trichormus azollae NtcA sequence was found as a phylogenetic outlier to horizontally infecting cyanobionts, which points to a distinct identity compared to symbiotic counterparts. There were borderline (60%-70%) levels of acceptable bootstrap support for the phylogenetic position of the Azolla cyanobiont's NtcA protein compared to other cyanobionts. Furthermore, the NtcA global nitrogen regulator in the Azolla cyanobiont has an extra cysteine at position 128, in addition to two other more conspicuous cysteines (positions, 157 and 164). A simulated homology model of the NtcA protein from Trichormus azollae, points to a single unique cysteine (Cysteine-128) as a key residue at the center of a lengthy C-helix, which forms a coiled-coil interface, through likely disulfide bond formation. Three cysteine (Cysteines: 128, 157, 164) architecture is exclusively found in Trichormus azollae and is absent in other cyanobacteria. A separate proline to alanine mutation in position 97-again exclusive to Trichormus azollae-appears to influence the flexibility of effector binding domain (EBD) to 2-oxoglutarate. The Trichormus azollae HetR sequence was found outside of horizontally-infecting cyanobiont sequences that formed a common clade, with the exception of the cyanobiont from the genus Cycas that formed one line of descent with the Trichormus azollae counterpart. Five (out of 6) serines predicted to be phosphorylated in the Trichormus azollae HetR sequence, are conserved in the Nostoc punctiforme counterpart, showcasing that phosphorylation is likley conserved in both vertically-transmitted and horizontally-acquired cyanobionts. A key Serine-127, within a conserved motif TSLTS, although conserved in heterocystous subsection IV and V cyanobacteria, are mutated in subsection III cyanobacteria that form trichomes but are unable to form heterocysts. I conclude that the NtcA protein from Trichormus azollae to be strategically divergent at specific amino acids that gives it an advantage in function as a 2-oxoglutarate-mediated transcription factor. The Trichormus azollae HetR transcription factor appears to possess parallel functionality to horizontally acquired counterparts. Especially Cysteine-128 in the NtcA transcription factor of the Azolla cyanobiont is an interesting proposition for future structure-function studies.
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Lima S, Matinha-Cardoso J, Tamagnini P, Oliveira P. Extracellular Vesicles: An Overlooked Secretion System in Cyanobacteria. Life (Basel) 2020; 10:E129. [PMID: 32751844 PMCID: PMC7459746 DOI: 10.3390/life10080129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 07/24/2020] [Accepted: 07/29/2020] [Indexed: 02/07/2023] Open
Abstract
In bacteria, the active transport of material from the interior to the exterior of the cell, or secretion, represents a very important mechanism of adaptation to the surrounding environment. The secretion of various types of biomolecules is mediated by a series of multiprotein complexes that cross the bacterial membrane(s), each complex dedicated to the secretion of specific substrates. In addition, biological material may also be released from the bacterial cell in the form of vesicles. Extracellular vesicles (EVs) are bilayered, nanoscale structures, derived from the bacterial cell envelope, which contain membrane components as well as soluble products. In cyanobacteria, the knowledge regarding EVs is lagging far behind compared to what is known about, for example, other Gram-negative bacteria. Here, we present a summary of the most important findings regarding EVs in Gram-negative bacteria, discussing aspects of their composition, formation processes and biological roles, and highlighting a number of technological applications tested. This lays the groundwork to raise awareness that the release of EVs by cyanobacteria likely represents an important, and yet highly disregarded, survival strategy. Furthermore, we hope to motivate future studies that can further elucidate the role of EVs in cyanobacterial cell biology and physiology.
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Affiliation(s)
- Steeve Lima
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, R. Alfredo Allen, 208, 4200-135 Porto, Portugal; (S.L.); (J.M.-C.); (P.T.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, R. Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Jorge Matinha-Cardoso
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, R. Alfredo Allen, 208, 4200-135 Porto, Portugal; (S.L.); (J.M.-C.); (P.T.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, R. Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Paula Tamagnini
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, R. Alfredo Allen, 208, 4200-135 Porto, Portugal; (S.L.); (J.M.-C.); (P.T.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, R. Alfredo Allen, 208, 4200-135 Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Edifício FC4, 4169-007 Porto, Portugal
| | - Paulo Oliveira
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, R. Alfredo Allen, 208, 4200-135 Porto, Portugal; (S.L.); (J.M.-C.); (P.T.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, R. Alfredo Allen, 208, 4200-135 Porto, Portugal
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Miranda AF, Kumar NR, Spangenberg G, Subudhi S, Lal B, Mouradov A. Aquatic Plants, Landoltia punctata, and Azolla filiculoides as Bio-Converters of Wastewater to Biofuel. Plants (Basel) 2020; 9:E437. [PMID: 32244834 PMCID: PMC7238415 DOI: 10.3390/plants9040437] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/26/2020] [Accepted: 03/26/2020] [Indexed: 12/17/2022]
Abstract
The aquatic plants, Azolla filiculoides, and Landoltia punctate, were used as complementing phytoremediators of wastewater containing high levels of phosphate, which simulates the effluents from textile, dyeing, and laundry detergent industries. Their complementarities are based on differences in capacities to uptake nitrogen and phosphate components from wastewater. Sequential treatment by L. punctata followed by A. filiculoides led to complete removal of NH4, NO3, and up to 93% reduction of PO4. In experiments where L. punctata treatment was followed by fresh L. punctata, PO4 concentration was reduced by 65%. The toxicity of wastewater assessed by shrimps, Paratya australiensis, showed a four-fold reduction of their mortality (LC50 value) after treatment. Collected dry biomass was used as an alternative carbon source for heterotrophic marine protists, thraustochytrids, which produced up to 35% dry weight of lipids rich in palmitic acid (50% of total fatty acids), the key fatty acid for biodiesel production. The fermentation of treated L. punctata biomass by Enterobacter cloacae yielded up to 2.14 mol H2/mole of reduced sugar, which is comparable with leading terrestrial feedstocks. A. filiculoides and L. punctata can be used as a new generation of feedstock, which can treat different types of wastewater and represent renewable and sustainable feedstock for bioenergy production.
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Affiliation(s)
- Ana F. Miranda
- School of Sciences, RMIT University, Bundoora West Campus, Bundoora VIC 3083, Australia;
| | - N. Ram Kumar
- The Energy and Resources Institute, New Delhi 110 003, India; (N.R.K.); (S.S.); (B.L.)
| | - German Spangenberg
- AgriBio, Centre for AgriBioscience, La Trobe University, Bundoora VIC 3083, Australia;
- School of Applied Systems Biology, La Trobe University, Bundoora VIC 3086, Australia
| | - Sanjukta Subudhi
- The Energy and Resources Institute, New Delhi 110 003, India; (N.R.K.); (S.S.); (B.L.)
| | - Banwari Lal
- The Energy and Resources Institute, New Delhi 110 003, India; (N.R.K.); (S.S.); (B.L.)
| | - Aidyn Mouradov
- School of Sciences, RMIT University, Bundoora West Campus, Bundoora VIC 3083, Australia;
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Langlete P, Krabberød AK, Winther-Larsen HC. Vesicles From Vibrio cholerae Contain AT-Rich DNA and Shorter mRNAs That Do Not Correlate With Their Protein Products. Front Microbiol 2019; 10:2708. [PMID: 31824470 PMCID: PMC6883915 DOI: 10.3389/fmicb.2019.02708] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/08/2019] [Indexed: 12/29/2022] Open
Abstract
Extracellular vesicles secreted by Gram-negative bacteria have proven to be important in bacterial defense, communication and host–pathogen relationships. They resemble smaller versions of the bacterial mother cell, with similar contents of proteins, LPS, DNA, and RNA. Vesicles can elicit a protective immune response in a range of hosts, and as vaccine candidates, it is of interest to properly characterize their cargo. Genetic sequencing data is already available for vesicles from several bacterial strains, but it is not yet clear how the genetic makeup of vesicles differ from that of their parent cells, and which properties may characterize enriched genetic material. The present study provides evidence for DNA inside vesicles from Vibrio cholerae O395, and key characteristics of their genetic and proteomic content are compared to that of whole cells. DNA analysis reveals enrichment of fragments containing ToxR binding sites, as well as a positive correlation between AT-content and enrichment. Some mRNAs were highly enriched in the vesicle fraction, such as membrane protein genes ompV, ompK, and ompU, DNA-binding protein genes hupA, hupB, ihfB, fis, and ssb, and a negative correlation was found between mRNA enrichment and transcript length, suggesting mRNA inclusion in vesicles may be a size-dependent process. Certain non-coding and functional RNAs were found to be enriched, such as VrrA, GcvB, tmRNA, RNase P, CsrB2, and CsrB3. Mass spectrometry revealed enrichment of outer membrane proteins, known virulence factors, phage components, flagella and extracellular proteins in the vesicle fraction, and a low, negative correlation was found between transcript-, and protein enrichment. This result opposes the hypothesis that a significant degree of protein translation occurs in vesicles after budding. The abundance of viral-, and flagellar proteins in the vesicle fraction underlines the importance of purification during vesicle isolation.
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Affiliation(s)
- Petter Langlete
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway.,Centre for Integrative Microbial Evolution (CIME), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Anders Kristian Krabberød
- Centre for Integrative Microbial Evolution (CIME), Department of Biosciences, University of Oslo, Oslo, Norway.,Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Hanne Cecilie Winther-Larsen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway.,Centre for Integrative Microbial Evolution (CIME), Department of Biosciences, University of Oslo, Oslo, Norway
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13
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de Vries S, de Vries J, Teschke H, von Dahlen JK, Rose LE, Gould SB. Jasmonic and salicylic acid response in the fern Azolla filiculoides and its cyanobiont. Plant Cell Environ 2018; 41:2530-2548. [PMID: 29314046 DOI: 10.1111/pce.13131] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/05/2017] [Accepted: 12/21/2017] [Indexed: 05/16/2023]
Abstract
Plants sense and respond to microbes utilizing a multilayered signalling cascade. In seed plants, the phytohormones jasmonic and salicylic acid (JA and SA) are key denominators of how plants respond to certain microbes. Their interplay is especially well-known for tipping the scales in plants' strategies of dealing with phytopathogens. In non-angiosperm lineages, the interplay is less well understood, but current data indicate that it is intertwined to a lesser extent and the canonical JA/SA antagonism appears to be absent. Here, we used the water fern Azolla filiculoides to gain insights into the fern's JA/SA signalling and the molecular communication with its unique nitrogen fixing cyanobiont Nostoc azollae, which the fern inherits both during sexual and vegetative reproduction. By mining large-scale sequencing data, we demonstrate that Azolla has most of the genetic repertoire to produce and sense JA and SA. Using qRT-PCR on the identified biosynthesis and signalling marker genes, we show that Azolla is responsive to exogenously applied SA. Furthermore, exogenous SA application influenced the abundance and gene expression of Azolla's cyanobiont. Our data provide a framework for JA/SA signalling in ferns and suggest that SA might be involved in Azolla's communication with its vertically inherited cyanobiont.
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Affiliation(s)
- Sophie de Vries
- Department of Biochemistry and Molecular Biology, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Jan de Vries
- Department of Biochemistry and Molecular Biology, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada
- Institute of Molecular Evolution, Heinrich-Heine University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Hendrik Teschke
- Institute of Molecular Evolution, Heinrich-Heine University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Janina K von Dahlen
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Laura E Rose
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
- Ceplas, Cluster of Excellence in Plant Sciences, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Sven B Gould
- Institute of Molecular Evolution, Heinrich-Heine University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
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Li FW, Brouwer P, Carretero-Paulet L, Cheng S, de Vries J, Delaux PM, Eily A, Koppers N, Kuo LY, Li Z, Simenc M, Small I, Wafula E, Angarita S, Barker MS, Bräutigam A, dePamphilis C, Gould S, Hosmani PS, Huang YM, Huettel B, Kato Y, Liu X, Maere S, McDowell R, Mueller LA, Nierop KGJ, Rensing SA, Robison T, Rothfels CJ, Sigel EM, Song Y, Timilsena PR, Van de Peer Y, Wang H, Wilhelmsson PKI, Wolf PG, Xu X, Der JP, Schluepmann H, Wong GKS, Pryer KM. Fern genomes elucidate land plant evolution and cyanobacterial symbioses. Nat Plants 2018; 4:460-472. [PMID: 29967517 PMCID: PMC6786969 DOI: 10.1038/s41477-018-0188-8] [Citation(s) in RCA: 246] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 05/24/2018] [Indexed: 05/18/2023]
Abstract
Ferns are the closest sister group to all seed plants, yet little is known about their genomes other than that they are generally colossal. Here, we report on the genomes of Azolla filiculoides and Salvinia cucullata (Salviniales) and present evidence for episodic whole-genome duplication in ferns-one at the base of 'core leptosporangiates' and one specific to Azolla. One fern-specific gene that we identified, recently shown to confer high insect resistance, seems to have been derived from bacteria through horizontal gene transfer. Azolla coexists in a unique symbiosis with N2-fixing cyanobacteria, and we demonstrate a clear pattern of cospeciation between the two partners. Furthermore, the Azolla genome lacks genes that are common to arbuscular mycorrhizal and root nodule symbioses, and we identify several putative transporter genes specific to Azolla-cyanobacterial symbiosis. These genomic resources will help in exploring the biotechnological potential of Azolla and address fundamental questions in the evolution of plant life.
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Affiliation(s)
- Fay-Wei Li
- Boyce Thompson Institute, Ithaca, NY, USA.
- Plant Biology Section, Cornell University, Ithaca, NY, USA.
| | - Paul Brouwer
- Molecular Plant Physiology Department, Utrecht University, Utrecht, the Netherlands
| | - Lorenzo Carretero-Paulet
- Bioinformatics Institute Ghent and Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Shifeng Cheng
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen, China
| | - Jan de Vries
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Pierre-Marc Delaux
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, Castanet Tolosan, France
| | - Ariana Eily
- Department of Biology, Duke University, Durham, NC, USA
| | - Nils Koppers
- Department of Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, Dusseldorf, Germany
| | | | - Zheng Li
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Mathew Simenc
- Department of Biological Science, California State University, Fullerton, CA, USA
| | - Ian Small
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Eric Wafula
- Department of Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Stephany Angarita
- Department of Biological Science, California State University, Fullerton, CA, USA
| | - Michael S Barker
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | | | - Claude dePamphilis
- Department of Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Sven Gould
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Dusseldorf, Germany
| | | | | | - Bruno Huettel
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding, Cologne, Germany
| | - Yoichiro Kato
- Institute for Sustainable Agro-ecosystem Services, University of Tokyo, Tokyo, Japan
| | - Xin Liu
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen, China
| | - Steven Maere
- Bioinformatics Institute Ghent and Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Rose McDowell
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | | | - Klaas G J Nierop
- Geolab, Faculty of Geosciences, Utrecht University, Utrecht, the Netherlands
| | | | - Tanner Robison
- Department of Biology, Utah State University, Logan, UT, USA
| | - Carl J Rothfels
- University Herbarium and Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - Erin M Sigel
- Department of Biology, University of Louisiana, Lafayette, LA, USA
| | - Yue Song
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen, China
| | - Prakash R Timilsena
- Department of Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Yves Van de Peer
- Bioinformatics Institute Ghent and Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Hongli Wang
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen, China
| | | | - Paul G Wolf
- Department of Biology, Utah State University, Logan, UT, USA
| | - Xun Xu
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen, China
| | - Joshua P Der
- Department of Biological Science, California State University, Fullerton, CA, USA
| | | | - Gane K-S Wong
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen, China
- Department of Biological Sciences, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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15
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Yang CJ, Hu JM. Bacterial Leaf Nodule Symbiosis in Flowering Plants. Symbiosis 2018. [DOI: 10.5772/intechopen.73078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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Abstract
The conversion of free-living cyanobacteria to photosynthetic organelles of eukaryotic cells through endosymbiosis transformed the biosphere and eventually provided the basis for life on land. Despite the presumable advantage conferred by the acquisition of photoautotrophy through endosymbiosis, only two independent cases of primary endosymbiosis have been documented: one that gave rise to the Archaeplastida, and the other to photosynthetic species of the thecate, filose amoeba Paulinella. Here, we review recent genomics-informed insights into the primary endosymbiotic origins of cyanobacteria-derived organelles. Furthermore, we discuss the preconditions for the evolution of nitrogen-fixing organelles. Recent genomic data on previously undersampled cyanobacterial and protist taxa provide new clues to the origins of the host cell and endosymbiont, and proteomic approaches allow insights into the rearrangement of the endosymbiont proteome during organellogenesis. We conclude that in addition to endosymbiotic gene transfers, horizontal gene acquisitions from a broad variety of prokaryotic taxa were crucial to organelle evolution.
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Affiliation(s)
- Eva C M Nowack
- Microbial Symbiosis and Organelle Evolution Group, Biology Department, Heinrich Heine University, 40225 Düsseldorf, Germany;
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany;
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17
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Miranda AF, Liu Z, Rochfort S, Mouradov A. Lipid production in aquatic plant Azolla at vegetative and reproductive stages and in response to abiotic stress. Plant Physiol Biochem 2018; 124:117-125. [PMID: 29366971 DOI: 10.1016/j.plaphy.2018.01.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/13/2018] [Accepted: 01/15/2018] [Indexed: 06/07/2023]
Abstract
The aquatic plant Azolla became increasingly popular as bioenergy feedstock because of its high growth rate, production of biomass with high levels of biofuel-producing molecules and ability to grow on marginal lands. In this study, we analysed the contribution of all organs of Azolla to the total yield of lipids at vegetative and reproductive stages and in response to stress. Triacylglycerol-containing lipid droplets were detected in all (vegetative and reproductive) organs with the highest level in the male microsporocarps and microspores. As a result, significantly higher total yields of lipids were detected in Azolla filiculoides and Azolla pinnata at the reproductive stage. Starving changed the yield and composition of the fatty acid as a result of re-direction of carbon flow from fatty acid to anthocyanin pathways. The composition of lipids, in regard the length and degree of unsaturation of fatty acids, in Azolla meets most of the important requirements for biodiesel standards. The ability of Azolla to grow on wastewaters, along with their high productivity rate, makes it an attractive feedstock for the production of biofuels.
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Affiliation(s)
- Ana F Miranda
- School of Sciences, RMIT University, Melbourne, VIC, Australia.
| | - Zhiqian Liu
- AgriBio, Centre for AgriBioscience, La Trobe University, Bundoora, VIC 3083, Australia.
| | - Simone Rochfort
- AgriBio, Centre for AgriBioscience, La Trobe University, Bundoora, VIC 3083, Australia.
| | - Aidyn Mouradov
- School of Sciences, RMIT University, Melbourne, VIC, Australia.
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18
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Zarantonello V, Silva TP, Noyma NP, Gamalier JP, Mello MM, Marinho MM, Melo RCN. The Cyanobacterium Cylindrospermopsis raciborskii (CYRF-01) Responds to Environmental Stresses with Increased Vesiculation Detected at Single-Cell Resolution. Front Microbiol 2018. [PMID: 29515552 PMCID: PMC5826386 DOI: 10.3389/fmicb.2018.00272] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Secretion of membrane-limited vesicles, collectively termed extracellular vesicles (EVs), is an important biological process of both eukaryotic and prokaryotic cells. This process has been observed in bacteria, but remains to be better characterized at high resolution in cyanobacteria. In the present work, we address the release of EVs by Cylindrospermopsis raciborskii (CYRF-01), a filamentous bloom-forming cyanobacterium, exposed to environmental stressors. First, non-axenic cultures of C. raciborskii (CYRF-01) were exposed to ultraviolet radiation (UVA + UVB) over a 6 h period, which is known to induce structural damage to this species. Second, C. raciborskii was co-cultured in interaction with another cyanobacterium species, Microcystis aeruginosa (MIRF-01), over a 24 h period. After the incubation times, cell density and viability were analyzed, and samples were processed for transmission electron microscopy (TEM). Our ultrastructural analyses revealed that C. raciborskii constitutively releases EVs from the outer membrane during its normal growth and amplifies such ability in response to environmental stressors. Both situations induced significant formation of outer membrane vesicles (OMVs) by C. raciborskii compared to control cells. Quantitative TEM revealed an increase of 48% (UV) and 60% (interaction) in the OMV numbers compared to control groups. Considering all groups, the OMVs ranged in size from 20 to 300 nm in diameter, with most OMVs showing diameters between 20 and 140 nm. Additionally, we detected that OMV formation is accompanied by phosphatidylserine exposure, a molecular event also observed in EV-secreting eukaryotic cells. Altogether, we identified for the first time that C. raciborskii has the competence to secrete OMVs and that under different stress situations the genesis of these vesicles is increased. The amplified ability of cyanobacteria to release OMVs may be associated with adaptive responses to changes in environmental conditions and interspecies cell communication.
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Affiliation(s)
- Victor Zarantonello
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Thiago P Silva
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Natália P Noyma
- Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Juliana P Gamalier
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Mariana M Mello
- Laboratory of Aquatic Ecology, Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Marcelo M Marinho
- Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Rossana C N Melo
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, Brazil
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19
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Dijkhuizen LW, Brouwer P, Bolhuis H, Reichart G, Koppers N, Huettel B, Bolger AM, Li F, Cheng S, Liu X, Wong GK, Pryer K, Weber A, Bräutigam A, Schluepmann H. Is there foul play in the leaf pocket? The metagenome of floating fern Azolla reveals endophytes that do not fix N 2 but may denitrify. New Phytol 2018; 217:453-466. [PMID: 29084347 PMCID: PMC5901025 DOI: 10.1111/nph.14843] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 09/05/2017] [Indexed: 05/18/2023]
Abstract
Dinitrogen fixation by Nostoc azollae residing in specialized leaf pockets supports prolific growth of the floating fern Azolla filiculoides. To evaluate contributions by further microorganisms, the A. filiculoides microbiome and nitrogen metabolism in bacteria persistently associated with Azolla ferns were characterized. A metagenomic approach was taken complemented by detection of N2 O released and nitrogen isotope determinations of fern biomass. Ribosomal RNA genes in sequenced DNA of natural ferns, their enriched leaf pockets and water filtrate from the surrounding ditch established that bacteria of A. filiculoides differed entirely from surrounding water and revealed species of the order Rhizobiales. Analyses of seven cultivated Azolla species confirmed persistent association with Rhizobiales. Two distinct nearly full-length Rhizobiales genomes were identified in leaf-pocket-enriched samples from ditch grown A. filiculoides. Their annotation revealed genes for denitrification but not N2 -fixation. 15 N2 incorporation was active in ferns with N. azollae but not in ferns without. N2 O was not detectably released from surface-sterilized ferns with the Rhizobiales. N2 -fixing N. azollae, we conclude, dominated the microbiome of Azolla ferns. The persistent but less abundant heterotrophic Rhizobiales bacteria possibly contributed to lowering O2 levels in leaf pockets but did not release detectable amounts of the strong greenhouse gas N2 O.
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Affiliation(s)
- Laura W. Dijkhuizen
- Molecular Plant Physiology DepartmentUtrecht UniversityPadualaan 8Utrecht3584CHthe Netherlands
| | - Paul Brouwer
- Molecular Plant Physiology DepartmentUtrecht UniversityPadualaan 8Utrecht3584CHthe Netherlands
| | - Henk Bolhuis
- Department of Marine Microbiology and BiogeochemistryNetherlands Institute for Sea Research (NIOZ)Utrecht UniversityDen Hoorn1797SZthe Netherlands
| | - Gert‐Jan Reichart
- Department of Earth SciencesUtrecht UniversityUtrecht3508TAthe Netherlands
| | - Nils Koppers
- Department of Plant BiochemistryCluster of Excellence on Plant Sciences (CEPLAS)Heinrich Heine UniversityDüsseldorf40225Germany
| | - Bruno Huettel
- Max Planck Institute for Plant Breeding ADIS/DNA Core FacilityCologne50829Germany
| | - Anthony M. Bolger
- Institute of Botany and Molecular Genetics IBMGIRWTH Aachen University52074AachenGermany
| | - Fay‐Wei Li
- Department of BiologyDuke UniversityDurhamNC27708USA
- Boyce Thompson Institute for Plant ResearchCornell UniversityIthacaNY14853USA
| | - Shifeng Cheng
- Beijing Genomics Institute‐ShenzhenShenzhen518083China
| | - Xin Liu
- Beijing Genomics Institute‐ShenzhenShenzhen518083China
| | - Gane Ka‐Shu Wong
- Beijing Genomics Institute‐ShenzhenShenzhen518083China
- Department of Biological SciencesUniversity of AlbertaEdmontonABT6G 2E9Canada
| | | | - Andreas Weber
- Department of Plant BiochemistryCluster of Excellence on Plant Sciences (CEPLAS)Heinrich Heine UniversityDüsseldorf40225Germany
| | - Andrea Bräutigam
- Department of Plant BiochemistryCluster of Excellence on Plant Sciences (CEPLAS)Heinrich Heine UniversityDüsseldorf40225Germany
| | - Henriette Schluepmann
- Molecular Plant Physiology DepartmentUtrecht UniversityPadualaan 8Utrecht3584CHthe Netherlands
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20
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Brouwer P, Bräutigam A, Buijs VA, Tazelaar AOE, van der Werf A, Schlüter U, Reichart GJ, Bolger A, Usadel B, Weber APM, Schluepmann H. Metabolic Adaptation, a Specialized Leaf Organ Structure and Vascular Responses to Diurnal N 2 Fixation by Nostoc azollae Sustain the Astonishing Productivity of Azolla Ferns without Nitrogen Fertilizer. Front Plant Sci 2017; 8:442. [PMID: 28408911 PMCID: PMC5374210 DOI: 10.3389/fpls.2017.00442] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/14/2017] [Indexed: 05/02/2023]
Abstract
Sustainable agriculture demands reduced input of man-made nitrogen (N) fertilizer, yet N2 fixation limits the productivity of crops with heterotrophic diazotrophic bacterial symbionts. We investigated floating ferns from the genus Azolla that host phototrophic diazotrophic Nostoc azollae in leaf pockets and belong to the fastest growing plants. Experimental production reported here demonstrated N-fertilizer independent production of nitrogen-rich biomass with an annual yield potential per ha of 1200 kg-1 N fixed and 35 t dry biomass. 15N2 fixation peaked at noon, reaching 0.4 mg N g-1 dry weight h-1. Azolla ferns therefore merit consideration as protein crops in spite of the fact that little is known about the fern's physiology to enable domestication. To gain an understanding of their nitrogen physiology, analyses of fern diel transcript profiles under differing nitrogen fertilizer regimes were combined with microscopic observations. Results established that the ferns adapted to the phototrophic N2-fixing symbionts N. azollae by (1) adjusting metabolically to nightly absence of N supply using responses ancestral to ferns and seed plants; (2) developing a specialized xylem-rich vasculature surrounding the leaf-pocket organ; (3) responding to N-supply by controlling transcripts of genes mediating nutrient transport, allocation and vasculature development. Unlike other non-seed plants, the Azolla fern clock is shown to contain both the morning and evening loops; the evening loop is known to control rhythmic gene expression in the vasculature of seed plants and therefore may have evolved along with the vasculature in the ancestor of ferns and seed plants.
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Affiliation(s)
- Paul Brouwer
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht UniversityUtrecht, Netherlands
| | - Andrea Bräutigam
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorf, Germany
| | - Valerie A. Buijs
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht UniversityUtrecht, Netherlands
| | - Anne O. E. Tazelaar
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht UniversityUtrecht, Netherlands
| | | | - Urte Schlüter
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorf, Germany
| | | | - Anthony Bolger
- Institute for Botany and Molecular Genetics, Bioeconomy Science Center, RWTH Aachen UniversityAachen, Germany
| | - Björn Usadel
- Institute for Botany and Molecular Genetics, Bioeconomy Science Center, RWTH Aachen UniversityAachen, Germany
| | - Andreas P. M. Weber
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorf, Germany
| | - Henriette Schluepmann
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht UniversityUtrecht, Netherlands
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21
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Liaimer A, Jensen JB, Dittmann E. A Genetic and Chemical Perspective on Symbiotic Recruitment of Cyanobacteria of the Genus Nostoc into the Host Plant Blasia pusilla L. Front Microbiol 2016; 7:1693. [PMID: 27847500 PMCID: PMC5088731 DOI: 10.3389/fmicb.2016.01693] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/10/2016] [Indexed: 12/04/2022] Open
Abstract
Liverwort Blasia pusilla L. recruits soil nitrogen-fixing cyanobacteria of genus Nostoc as symbiotic partners. In this work we compared Nostoc community composition inside the plants and in the soil around them from two distant locations in Northern Norway. STRR fingerprinting and 16S rDNA phylogeny reconstruction showed a remarkable local diversity among isolates assigned to several Nostoc clades. An extensive web of negative allelopathic interactions was recorded at an agricultural site, but not at the undisturbed natural site. The cell extracts of the cyanobacteria did not show antimicrobial activities, but four isolates were shown to be cytotoxic to human cells. The secondary metabolite profiles of the isolates were mapped by MALDI-TOF MS, and the most prominent ions were further analyzed by Q-TOF for MS/MS aided identification. Symbiotic isolates produced a great variety of small peptide-like substances, most of which lack any record in the databases. Among identified compounds we found microcystin and nodularin variants toxic to eukaryotic cells. Microcystin producing chemotypes were dominating as symbiotic recruits but not in the free-living community. In addition, we were able to identify several novel aeruginosins and banyaside-like compounds, as well as nostocyclopeptides and nosperin.
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Affiliation(s)
- Anton Liaimer
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT-The Arctic University of NorwayTromsø, Norway
| | - John B. Jensen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT-The Arctic University of NorwayTromsø, Norway
| | - Elke Dittmann
- Department of Microbiology, Institute for Biochemistry and Biology, University of PotsdamPotsdam, Germany
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Vigil-Stenman T, Larsson J, Nylander JAA, Bergman B. Local hopping mobile DNA implicated in pseudogene formation and reductive evolution in an obligate cyanobacteria-plant symbiosis. BMC Genomics 2015; 16:193. [PMID: 25885210 PMCID: PMC4369082 DOI: 10.1186/s12864-015-1386-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 02/24/2015] [Indexed: 12/15/2022] Open
Abstract
Background Insertion sequences (ISs) are approximately 1 kbp long “jumping” genes found in prokaryotes. ISs encode the protein Transposase, which facilitates the excision and reinsertion of ISs in genomes, making these sequences a type of class I (“cut-and-paste”) Mobile Genetic Elements. ISs are proposed to be involved in the reductive evolution of symbiotic prokaryotes. Our previous sequencing of the genome of the cyanobacterium ‘Nostoc azollae’ 0708, living in a tight perpetual symbiotic association with a plant (the water fern Azolla), revealed the presence of an eroding genome, with a high number of insertion sequences (ISs) together with an unprecedented large proportion of pseudogenes. To investigate the role of ISs in the reductive evolution of ‘Nostoc azollae’ 0708, and potentially in the formation of pseudogenes, a bioinformatic investigation of the IS identities and positions in 47 cyanobacterial genomes was conducted. To widen the scope, the IS contents were analysed qualitatively and quantitatively in 20 other genomes representing both free-living and symbiotic bacteria. Results Insertion Sequences were not randomly distributed in the bacterial genomes and were found to transpose short distances from their original location (“local hopping”) and pseudogenes were enriched in the vicinity of IS elements. In general, symbiotic organisms showed higher densities of IS elements and pseudogenes than non-symbiotic bacteria. A total of 1108 distinct repeated sequences over 500 bp were identified in the 67 genomes investigated. In the genome of ‘Nostoc azollae’ 0708, IS elements were apparent at 970 locations (14.3%), with 428 being full-length. Morphologically complex cyanobacteria with large genomes showed higher frequencies of IS elements, irrespective of life style. Conclusions The apparent co-location of IS elements and pseudogenes found in prokaryotic genomes implies earlier IS transpositions into genes. As transpositions tend to be local rather than genome wide this likely explains the proximity between IS elements and pseudogenes. These findings suggest that ISs facilitate the reductive evolution in for instance in the symbiotic cyanobacterium ‘Nostoc azollae’ 0708 and in other obligate prokaryotic symbionts. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1386-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Theoden Vigil-Stenman
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Science for Life Laboratory, SE-17165, Solna, Sweden.
| | - John Larsson
- Department of Biology and Environmental Science, Linné University, Science for Life Laboratory, SE-17165, Solna, Sweden.
| | - Johan A A Nylander
- BILS/Swedish Museum of Natural History, Science for Life Laboratory, SE-17165, Solna, Sweden.
| | - Birgitta Bergman
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Science for Life Laboratory, SE-17165, Solna, Sweden.
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Brouwer P, Bräutigam A, Külahoglu C, Tazelaar AOE, Kurz S, Nierop KGJ, van der Werf A, Weber APM, Schluepmann H. Azolla domestication towards a biobased economy? New Phytol 2014; 202:1069-1082. [PMID: 24494738 DOI: 10.1111/nph.12708] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 12/22/2013] [Indexed: 05/05/2023]
Abstract
Due to its phenomenal growth requiring neither nitrogen fertilizer nor arable land and its biomass composition, the mosquito fern Azolla is a candidate crop to yield food, fuels and chemicals sustainably. To advance Azolla domestication, we research its dissemination, storage and transcriptome. Methods for dissemination, cross-fertilization and cryopreservation of the symbiosis Azolla filiculoides-Nostoc azollae are tested based on the fern spores. To study molecular processes in Azolla including spore induction, a database of 37 649 unigenes from RNAseq of microsporocarps, megasporocarps and sporophytes was assembled, then validated. Spores obtained year-round germinated in vitro within 26 d. In vitro fertilization rates reached 25%. Cryopreservation permitted storage for at least 7 months. The unigene database entirely covered central metabolism and to a large degree covered cellular processes and regulatory networks. Analysis of genes engaged in transition to sexual reproduction revealed a FLOWERING LOCUS T-like protein in ferns with special features induced in sporulating Azolla fronds. Although domestication of a fern-cyanobacteria symbiosis may seem a daunting task, we conclude that the time is ripe and that results generated will serve to more widely access biochemicals in fern biomass for a biobased economy.
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Affiliation(s)
- Paul Brouwer
- Molecular Plant Physiology Department, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Andrea Bräutigam
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Canan Külahoglu
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Anne O E Tazelaar
- Molecular Plant Physiology Department, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Samantha Kurz
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Klaas G J Nierop
- Organic Geochemistry, Utrecht University, Budapestlaan 4, 3584 CD, Utrecht, the Netherlands
| | - Adrie van der Werf
- Plant Research International, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Andreas P M Weber
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Henriette Schluepmann
- Molecular Plant Physiology Department, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
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24
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Pereira AL, Vasconcelos V. Classification and phylogeny of the cyanobiont Anabaena azollae Strasburger: an answered question? Int J Syst Evol Microbiol 2014; 64:1830-1840. [PMID: 24737795 DOI: 10.1099/ijs.0.059238-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The symbiosis Azolla-Anabaena azollae, with a worldwide distribution in pantropical and temperate regions, is one of the most studied, because of its potential application as a biofertilizer, especially in rice fields, but also as an animal food and in phytoremediation. The cyanobiont is a filamentous, heterocystic cyanobacterium that inhabits the foliar cavities of the pteridophyte and the indusium on the megasporocarp (female reproductive structure). The classification and phylogeny of the cyanobiont is very controversial: from its morphology, it has been named Nostoc azollae, Anabaena azollae, Anabaena variabilis status azollae and recently Trichormus azollae, but, from its 16S rRNA gene sequence, it has been assigned to Nostoc and/or Anabaena, and from its phycocyanin gene sequence, it has been assigned as non-Nostoc and non-Anabaena. The literature also points to a possible co-evolution between the cyanobiont and the Azolla host, since dendrograms and phylogenetic trees of fatty acids, short tandemly repeated repetitive (STRR) analysis and restriction fragment length polymorphism (RFLP) analysis of nif genes and the 16S rRNA gene give a two-cluster association that matches the two-section ranking of the host (Azolla). Another controversy surrounds the possible existence of more than one genus or more than one species strain. The use of freshly isolated or cultured cyanobionts is an additional problem, since their morphology and protein profiles are different. This review gives an overview of how morphological, chemical and genetic analyses influence the classification and phylogeny of the cyanobiont and future research.
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Affiliation(s)
- Ana L Pereira
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal
| | - Vitor Vasconcelos
- Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre, 4069-007 Porto, Portugal
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal
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25
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Zheng W, Rasmussen U, Zheng S, Bao X, Chen B, Gao Y, Guan X, Larsson J, Bergman B. Multiple Modes of Cell Death Discovered in a Prokaryotic (Cyanobacterial) Endosymbiont. PLoS One 2013; 8:e66147. [PMID: 23822984 PMCID: PMC3688857 DOI: 10.1371/journal.pone.0066147] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 05/02/2013] [Indexed: 02/01/2023] Open
Abstract
Programmed cell death (PCD) is a genetically-based cell death mechanism with vital roles in eukaryotes. Although there is limited consensus on similar death mode programs in prokaryotes, emerging evidence suggest that PCD events are operative. Here we present cell death events in a cyanobacterium living endophytically in the fern Azolla microphylla, suggestive of PCD. This symbiosis is characterized by some unique traits such as a synchronized development, a vertical transfer of the cyanobacterium between plant generations, and a highly eroding cyanobacterial genome. A combination of methods was used to identify cell death modes in the cyanobacterium. Light- and electron microscopy analyses showed that the proportion of cells undergoing cell death peaked at 53.6% (average 20%) of the total cell population, depending on the cell type and host developmental stage. Biochemical markers used for early and late programmed cell death events related to apoptosis (Annexin V-EGFP and TUNEL staining assays), together with visualization of cytoskeleton alterations (FITC-phalloidin staining), showed that all cyanobacterial cell categories were affected by cell death. Transmission electron microscopy revealed four modes of cell death: apoptotic-like, autophagic-like, necrotic-like and autolytic-like. Abiotic stresses further enhanced cell death in a dose and time dependent manner. The data also suggest that dynamic changes in the peptidoglycan cell wall layer and in the cytoskeleton distribution patterns may act as markers for the various cell death modes. The presence of a metacaspase homolog (domain p20) further suggests that the death modes are genetically programmed. It is therefore concluded that multiple, likely genetically programmed, cell death modes exist in cyanobacteria, a finding that may be connected with the evolution of cell death in the plant kingdom.
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Affiliation(s)
- Weiwen Zheng
- Key Laboratory of Bio-Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
- Biotech Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Ulla Rasmussen
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Siping Zheng
- Biotech Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Xiaodong Bao
- Department of Plant Pathology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Bin Chen
- Biotech Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Yuan Gao
- Key Laboratory of Bio-Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiong Guan
- Key Laboratory of Bio-Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China
| | - John Larsson
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Birgitta Bergman
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- * E-mail:
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26
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Xu Y, Guerra LT, Li Z, Ludwig M, Dismukes GC, Bryant DA. Altered carbohydrate metabolism in glycogen synthase mutants of Synechococcus sp. strain PCC 7002: Cell factories for soluble sugars. Metab Eng 2012; 16:56-67. [PMID: 23262095 DOI: 10.1016/j.ymben.2012.12.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 11/19/2012] [Accepted: 12/04/2012] [Indexed: 02/07/2023]
Abstract
Glycogen and compatible solutes are the major polymeric and soluble carbohydrates in cyanobacteria and function as energy reserves and osmoprotectants, respectively. Glycogen synthase null mutants (glgA-I glgA-II) were constructed in the cyanobacterium Synechococcus sp. strain PCC 7002. Under standard conditions the double mutant produced no glycogen and more soluble sugars. When grown under hypersaline conditions, the glgA-I glgA-II mutant accumulated 1.8-fold more soluble sugars (sucrose and glucosylglycer-(ol/ate)) than WT, and these cells spontaneously excreted soluble sugars into the medium at high levels without the need for additional transporters. An average of 27% more soluble sugars was released from the glgA-I glgA-II mutant than WT by hypo-osmotic shock. Extracellular vesicles budding from the outer membrane were observed by transmission electron microscopy in glgA-I glgA-II cells grown under hypersaline conditions. The glgA-I glgA-II mutant serves as a starting point for developing cell factories for photosynthetic production and excretion of sugars.
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Affiliation(s)
- Yu Xu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
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27
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Krause K, Oetke S, Krupinska K. Dual targeting and retrograde translocation: regulators of plant nuclear gene expression can be sequestered by plastids. Int J Mol Sci 2012; 13:11085-11101. [PMID: 23109840 PMCID: PMC3472732 DOI: 10.3390/ijms130911085] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 08/21/2012] [Accepted: 08/23/2012] [Indexed: 11/16/2022] Open
Abstract
Changes in the developmental or metabolic state of plastids can trigger profound changes in the transcript profiles of nuclear genes. Many nuclear transcription factors were shown to be controlled by signals generated in the organelles. In addition to the many different compounds for which an involvement in retrograde signaling is discussed, accumulating evidence suggests a role for proteins in plastid-to-nucleus communication. These proteins might be sequestered in the plastids before they act as transcriptional regulators in the nucleus. Indeed, several proteins exhibiting a dual localization in the plastids and the nucleus are promising candidates for such a direct signal transduction involving regulatory protein storage in the plastids. Among such proteins, the nuclear transcription factor WHIRLY1 stands out as being the only protein for which an export from plastids and translocation to the nucleus has been experimentally demonstrated. Other proteins, however, strongly support the notion that this pathway might be more common than currently believed.
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Affiliation(s)
- Kirsten Krause
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø 9037, Norway; E-Mail:
| | - Svenja Oetke
- Institute of Botany, University of Kiel, Olshausenstrasse 40, Kiel 24098, Germany; E-Mail:
| | - Karin Krupinska
- Institute of Botany, University of Kiel, Olshausenstrasse 40, Kiel 24098, Germany; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-431-880-4240; Fax: +49-431-880-4238
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28
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Abstract
Several plant species of the genus Psychotria (Rubiaceae) harbour Burkholderia sp. bacteria within specialized leaf nodules. The bacteria are transmitted vertically between plant generations and have not yet been cultured outside of their host. This symbiosis is also generally described as obligatory because plants devoid of symbionts fail to develop into mature individuals. We sequenced for the first time the genome of the symbiont of Psychotria kirkii in order to shed some light on the nature of their symbiotic relationship. We found that the 4 Mb genome of Candidatus Burkholderia kirkii (B. kirkii) is small for a Burkholderia species and displays features consistent with ongoing genome erosion such as large proportions of pseudogenes and transposable elements. Reductive genome evolution affected a wide array of functional categories that may hinder the ability of the symbiont to be free-living. The genome does not encode functions commonly found in plant symbionts such as nitrogen fixation or plant hormone metabolism. Instead, a collection of genes for secondary metabolites' synthesis is located on the 140 kb plasmid of B. kirkii and suggests that leaf nodule symbiosis benefits the host by providing protection against herbivores or pathogens.
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Affiliation(s)
- Aurelien L Carlier
- Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland.
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30
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Larsson J, Nylander JAA, Bergman B. Genome fluctuations in cyanobacteria reflect evolutionary, developmental and adaptive traits. BMC Evol Biol 2011; 11:187. [PMID: 21718514 PMCID: PMC3141437 DOI: 10.1186/1471-2148-11-187] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 06/30/2011] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Cyanobacteria belong to an ancient group of photosynthetic prokaryotes with pronounced variations in their cellular differentiation strategies, physiological capacities and choice of habitat. Sequencing efforts have shown that genomes within this phylum are equally diverse in terms of size and protein-coding capacity. To increase our understanding of genomic changes in the lineage, the genomes of 58 contemporary cyanobacteria were analysed for shared and unique orthologs. RESULTS A total of 404 protein families, present in all cyanobacterial genomes, were identified. Two of these are unique to the phylum, corresponding to an AbrB family transcriptional regulator and a gene that escapes functional annotation although its genomic neighbourhood is conserved among the organisms examined. The evolution of cyanobacterial genome sizes involves a mix of gains and losses in the clade encompassing complex cyanobacteria, while a single event of reduction is evident in a clade dominated by unicellular cyanobacteria. Genome sizes and gene family copy numbers evolve at a higher rate in the former clade, and multi-copy genes were predominant in large genomes. Orthologs unique to cyanobacteria exhibiting specific characteristics, such as filament formation, heterocyst differentiation, diazotrophy and symbiotic competence, were also identified. An ancestral character reconstruction suggests that the most recent common ancestor of cyanobacteria had a genome size of approx. 4.5 Mbp and 1678 to 3291 protein-coding genes, 4%-6% of which are unique to cyanobacteria today. CONCLUSIONS The different rates of genome-size evolution and multi-copy gene abundance suggest two routes of genome development in the history of cyanobacteria. The expansion strategy is driven by gene-family enlargment and generates a broad adaptive potential; while the genome streamlining strategy imposes adaptations to highly specific niches, also reflected in their different functional capacities. A few genomes display extreme proliferation of non-coding nucleotides which is likely to be the result of initial expansion of genomes/gene copy number to gain adaptive potential, followed by a shift to a life-style in a highly specific niche (e.g. symbiosis). This transition results in redundancy of genes and gene families, leading to an increase in junk DNA and eventually to gene loss. A few orthologs can be correlated with specific phenotypes in cyanobacteria, such as filament formation and symbiotic competence; these constitute exciting exploratory targets.
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Affiliation(s)
- John Larsson
- Department of Botany, Stockholm University, SE-106 09, Stockholm, Sweden
| | - Johan AA Nylander
- Department of Botany, Stockholm University, SE-106 09, Stockholm, Sweden
- Natural History Museum, University of Oslo, P.O. Box 1172 Blindern, NO-0318 Oslo, Norway
| | - Birgitta Bergman
- Department of Botany, Stockholm University, SE-106 09, Stockholm, Sweden
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31
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Ran L, Larsson J, Vigil-Stenman T, Nylander JAA, Ininbergs K, Zheng WW, Lapidus A, Lowry S, Haselkorn R, Bergman B. Genome erosion in a nitrogen-fixing vertically transmitted endosymbiotic multicellular cyanobacterium. PLoS One 2010; 5:e11486. [PMID: 20628610 PMCID: PMC2900214 DOI: 10.1371/journal.pone.0011486] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 06/13/2010] [Indexed: 11/29/2022] Open
Abstract
Background An ancient cyanobacterial incorporation into a eukaryotic organism led to the evolution of plastids (chloroplasts) and subsequently to the origin of the plant kingdom. The underlying mechanism and the identities of the partners in this monophyletic event remain elusive. Methodology/Principal Findings To shed light on this evolutionary process, we sequenced the genome of a cyanobacterium residing extracellularly in an endosymbiosis with a plant, the water-fern Azolla filiculoides Lam. This symbiosis was selected as it has characters which make it unique among extant cyanobacterial plant symbioses: the cyanobacterium lacks autonomous growth and is vertically transmitted between plant generations. Our results reveal features of evolutionary significance. The genome is in an eroding state, evidenced by a large proportion of pseudogenes (31.2%) and a high frequency of transposable elements (∼600) scattered throughout the genome. Pseudogenization is found in genes such as the replication initiator dnaA and DNA repair genes, considered essential to free-living cyanobacteria. For some functional categories of genes pseudogenes are more prevalent than functional genes. Loss of function is apparent even within the ‘core’ gene categories of bacteria, such as genes involved in glycolysis and nutrient uptake. In contrast, serving as a critical source of nitrogen for the host, genes related to metabolic processes such as cell differentiation and nitrogen-fixation are well preserved. Conclusions/Significance This is the first finding of genome degradation in a plant symbiont and phenotypically complex cyanobacterium and one of only a few extracellular endosymbionts described showing signs of reductive genome evolution. Our findings suggest an ongoing selective streamlining of this cyanobacterial genome which has resulted in an organism devoted to nitrogen fixation and devoid of autonomous growth. The cyanobacterial symbiont of Azolla can thus be considered at the initial phase of a transition from free-living organism to a nitrogen-fixing plant entity, a transition process which may mimic what drove the evolution of chloroplasts from a cyanobacterial ancestor.
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Affiliation(s)
- Liang Ran
- Department of Botany, Stockholm University, Stockholm, Sweden
| | - John Larsson
- Department of Botany, Stockholm University, Stockholm, Sweden
| | | | | | | | - Wei-Wen Zheng
- Biotechnology Research Center, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Alla Lapidus
- Department of Energy Joint Genome Institute, Walnut Creek, California, United States of America
| | - Stephen Lowry
- Department of Energy Joint Genome Institute, Walnut Creek, California, United States of America
| | - Robert Haselkorn
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, United States of America
| | - Birgitta Bergman
- Department of Botany, Stockholm University, Stockholm, Sweden
- * E-mail:
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