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Le VV, Tran QG, Ko SR, Oh HM, Ahn CY. Insights into cyanobacterial blooms through the lens of omics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 934:173028. [PMID: 38723963 DOI: 10.1016/j.scitotenv.2024.173028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 05/04/2024] [Accepted: 05/04/2024] [Indexed: 05/20/2024]
Abstract
Cyanobacteria are oxygen-producing photosynthetic bacteria that convert carbon dioxide into biomass upon exposure to sunlight. However, favorable conditions cause harmful cyanobacterial blooms (HCBs), which are the dense accumulation of biomass at the water surface or subsurface, posing threats to freshwater ecosystems and human health. Understanding the mechanisms underlying cyanobacterial bloom formation is crucial for effective management. In this regard, recent advancements in omics technologies have provided valuable insights into HCBs, which have raised expectations to develop more effective control methods in the near future. This literature review aims to present the genomic architecture, adaptive mechanisms, microbial interactions, and ecological impacts of HCBs through the lens of omics. Genomic analysis indicates that the genome plasticity of cyanobacteria has enabled their resilience and effective adaptation to environmental changes. Transcriptomic investigations have revealed that cyanobacteria use various strategies for adapting to environmental stress. Additionally, metagenomic and metatranscriptomic analyses have emphasized the significant role of the microbial community in regulating HCBs. Finally, we offer perspectives on potential opportunities for further research in this field.
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Affiliation(s)
- Ve Van Le
- Cell factory Research Centre, Korea Research Institute of Bioscience & Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | | | - So-Ra Ko
- Cell factory Research Centre, Korea Research Institute of Bioscience & Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hee-Mock Oh
- Cell factory Research Centre, Korea Research Institute of Bioscience & Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Department of Environmental Biotechnology, KRIBB School of Biotechnology, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Chi-Yong Ahn
- Cell factory Research Centre, Korea Research Institute of Bioscience & Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Department of Environmental Biotechnology, KRIBB School of Biotechnology, University of Science and Technology, Daejeon 34113, Republic of Korea.
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Barcia-Cruz R, Balboa S, Lema A, Romalde JL. Comparative genomics of Vibrio toranzoniae strains. RESEARCH SQUARE 2024:rs.3.rs-4360386. [PMID: 38826277 PMCID: PMC11142368 DOI: 10.21203/rs.3.rs-4360386/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Vibrio toranzoniae is a marine bacterium belonging to the Splendidus clade, originally isolated from healthy clams in Galicia (NW Spain). Its isolation from different hosts and seawater indicated two lifestyles and wide geographical distribution. The aim of the present study was to determine the differences at genome level among strains, as well as to determine their phylogeny. For this purpose, whole genomes were sequenced by different technologies and the resulting sequences corrected. Genomes were annotated and compared with different online tools. Furthermore, the study of core and pan genome was examined, and the phylogeny was inferred. The content of the core genome ranged from 2,953 to 2,766 genes and that of the pangenome from 6,278 to 6,132, depending on the tool used. The comparison revealed that although the strains shared certain homology, with DDH values ranging from 77.10 to 82.30 and values of OrthoANI higher than 97%,notable differences were found related to motility, capsule synthesis, iron acquisition system or mobile genetic elements. The phylogenetic analysis of the core genome did not reveal a differentiation of the strains according to their lifestyle, but that of the pangenome pointed out certain geographical isolation in the same growing area. The study led to a reclassification of some isolates formerly described as V. toranzoniae and manifested the importance of cured deposited sequences to proper phylogenetic assignment.
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3
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Wang X, Fan C, Sun J. Utilization and transformation of Chrysotila dentata-derived dissolved organic matter by phycosphere bacteria Marinobacter hydrocarbonoclasticus and Bacillus firmus. PeerJ 2024; 12:e16552. [PMID: 38188179 PMCID: PMC10771764 DOI: 10.7717/peerj.16552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 11/09/2023] [Indexed: 01/09/2024] Open
Abstract
The dissolved organic matter (DOM) released from the cocoolithophores (Chrysotila dentata) was studied in laboratory experiments after co-culturing C. dentata with bacteria. Marinobacter hydrocarbonoclasticus (CA6)-γ-Proteobacteria and Bacillus firmus (CF2) were used to investigate the utilization and processing of the DOM derived from C. dentata, utilizing fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (EEM-PARAFAC), while measuring algal abundance and photosynthetic parameters. The experimental groups consisted of axenic C. dentata groups, filter cultured with bacteria (CA6 or CF2) groups, C. dentata co-cultured with bacteria (CA6 or CF2) groups and axenic bacteria (CA6 or CF2) groups. We then evaluated the processing of DOM by determining four fluorescence indices. The number of C. dentata cells and the photosynthetic capacity of microalgae were enhanced by CA6 and CF2. The main known fluorophores, including humic-like components and protein-like components, were present in all sample. The protein-like component of algal-bacterial co-cultures was effectively utilized by CA6 and CF2. The humic-like components increased at the end of the culture time for all cultures. Meanwhile, the average fluorescence intensity of protein-like in CA6 co-culture with algae was lower than that in CF2 co-culture with algae over time. On the other hand, the average fluorescence intensity of humic-like in CA6 was higher than CF2. However, the total change in fluorescence in humic-like and protein-like of axenic CF2 cultures was lower than that of CA6. Hence, the ability of CA6 to transform microalgal-derived DOM was superior to that of CF2, and CF2's ability to consume bacterial-derived DOM was superior to that of CA6.
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Affiliation(s)
- Xueru Wang
- China University of Geosciences, Institute for Advance Marine Research, Guangzhou, China
- China University of Geosciences, State Key Laboratory of Biogeology and Environmental Geology, Wuhan, China
- Tianjin University of Science and Technology, Research Centre for Indian Ocean Ecosystem, Tianjin, China
| | - Chenjuan Fan
- Tianjin University of Science and Technology, Research Centre for Indian Ocean Ecosystem, Tianjin, China
| | - Jun Sun
- China University of Geosciences, Institute for Advance Marine Research, Guangzhou, China
- China University of Geosciences, State Key Laboratory of Biogeology and Environmental Geology, Wuhan, China
- Tianjin University of Science and Technology, Research Centre for Indian Ocean Ecosystem, Tianjin, China
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4
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Shao Q, Zhu Z, Zhou C. Alteration in Community Dynamics of Chaetoceros curvisetus and Bacterioplankton Communities in Response to Surfactin Exposure. Microorganisms 2023; 11:2596. [PMID: 37894254 PMCID: PMC10609649 DOI: 10.3390/microorganisms11102596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
The use of surfactin is a promising method to mitigate algal blooms. However, little is known about surfactin toxicity to algae and bacterioplankton. Here, we treated Chaetoceros curvisetus, the dominant species of algal blooms in the East China Sea, with 0, 0.5, 1, 2, 3, and 4 mg/L of surfactin for 96 h to investigate temporal variability. Our results showed that low concentrations of surfactin (<2 mg/L) changed the cell morphology of C. curvisetus, and higher concentrations (>3 mg/L) had lethal effects. Meanwhile, we examined the community dynamics of the free-living (FL, 0.22-5 μm) and particle-attached (PA, >5 μm) bacterioplankton of C. curvisetus in response to different surfactin concentrations and cultivation periods. Both PA and FL bacterioplankton were mainly composed of Proteobacteria, Actinobacteria, and Bacteroidetes, while FL bacterioplankton were more diverse than PA bacterioplankton. The variations of FL and PA bacterioplankton were significantly constrained by the surfactin concentration. Surfactin changed the lifestyle of some bacterioplankton from FL to PA, which mainly belonged to abundant bacterioplankton. Furthermore, we identified some surfactin-sensitive species/taxa. Our study will help enhance the ability to predict marine microbial responses under the effect of surfactin, providing a research foundation for this new harmful algal bloom mitigation method.
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Affiliation(s)
- Qianwen Shao
- Ningbo Institute of Oceanography, Ningbo 315832, China;
- Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
| | - Zhujun Zhu
- Ningbo Institute of Oceanography, Ningbo 315832, China;
| | - Chengxu Zhou
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315832, China;
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5
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Liu Y, Ma C, Sun J. Integrated FT-ICR MS and metabolome reveals diatom-derived organic matter by bacterial transformation under warming and acidification. iScience 2023; 26:106812. [PMID: 37213222 PMCID: PMC10197009 DOI: 10.1016/j.isci.2023.106812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 02/21/2023] [Accepted: 05/01/2023] [Indexed: 05/23/2023] Open
Abstract
Bacterial transformation and processing of diatom-derived organic matter (OM) is extremely important for the cycling of production and energy in marine ecosystems; this process contributes to the production of microbial food webs. In this study, a cultivable bacterium (Roseobacter sp. SD-R1) from the marine diatom Skeletonema dohrnii were isolated and identified. A combined Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS)/untargeted metabolomics approach was used to synthesize the results of bacterial transformation with dissolved OM (DOM) and lysate OM (LOM) under warming and acidification through laboratory experiments. Roseobacter sp. SD-R1 had different preferences for the conversion of molecules in S. dohrnii-derived DOM and LOM treatments. The effects of warming and acidification contribute to the increased number and complexity of molecules of carbon, hydrogen, oxygen, nitrogen, and sulfur after the bacterial transformation of OM. The chemical complexity generated by bacterial metabolism provides new insights into the mechanisms that shape OM complexity.
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Affiliation(s)
- Yang Liu
- Institute for Advance Marine Research, China University of Geosciences, Guangzhou 511462, China
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
- Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China
| | - Chao Ma
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Jun Sun
- Institute for Advance Marine Research, China University of Geosciences, Guangzhou 511462, China
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
- Corresponding author
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Chiriac MC, Haber M, Salcher MM. Adaptive genetic traits in pelagic freshwater microbes. Environ Microbiol 2023; 25:606-641. [PMID: 36513610 DOI: 10.1111/1462-2920.16313] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 12/12/2022] [Indexed: 12/15/2022]
Abstract
Pelagic microbes have adopted distinct strategies to inhabit the pelagial of lakes and oceans and can be broadly categorized in two groups: free-living, specialized oligotrophs and patch-associated generalists or copiotrophs. In this review, we aim to identify genomic traits that enable pelagic freshwater microbes to thrive in their habitat. To do so, we discuss the main genetic differences of pelagic marine and freshwater microbes that are both dominated by specialized oligotrophs and the difference to freshwater sediment microbes, where copiotrophs are more prevalent. We phylogenomically analysed a collection of >7700 metagenome-assembled genomes, classified habitat preferences on different taxonomic levels, and compared the metabolic traits of pelagic freshwater, marine, and freshwater sediment microbes. Metabolic differences are mainly associated with transport functions, environmental information processing, components of the electron transport chain, osmoregulation and the isoelectric point of proteins. Several lineages with known habitat transitions (Nitrososphaeria, SAR11, Methylophilaceae, Synechococcales, Flavobacteriaceae, Planctomycetota) and the underlying mechanisms in this process are discussed in this review. Additionally, the distribution, ecology and genomic make-up of the most abundant freshwater prokaryotes are described in details in separate chapters for Actinobacteriota, Bacteroidota, Burkholderiales, Verrucomicrobiota, Chloroflexota, and 'Ca. Patescibacteria'.
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Affiliation(s)
| | - Markus Haber
- Institute of Hydrobiology, Biology Centre CAS, Ceske Budejovice, Czechia
| | - Michaela M Salcher
- Institute of Hydrobiology, Biology Centre CAS, Ceske Budejovice, Czechia
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7
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Raiyani NM, Singh SP. Microbial community and predictive functionalities associated with the marine sediment of Coastal Gujarat. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:43245-43266. [PMID: 36650368 DOI: 10.1007/s11356-023-25196-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 01/04/2023] [Indexed: 01/19/2023]
Abstract
Marine sediments are complex ecosystems where structures and functions constantly change due to natural and anthropogenic influences. In this investigation, a comprehensive and comparative analysis of the bacterial communities and their functional potential of the pristine and polluted marine sediments were carried out using MiSeq. The phylum Proteobacteria was dominant in all study sites. Other phyla were Actinobacteria, Bacteroidetes, Planctomycetes, Acidobacteria, Chloroflexi, Nitrospirae, Cyanobacteria, Verrucomicrobia, Tenericutes, and Chlorobi. Interestingly, about 50% of genera belong to the unclassified categories. The key genera were identified as Acinetobacter, Bacillus, Pseudomona, Idiomarina, Thalassospira, and Marinobacter, Halomonas, Planctomyces, Psychrobacter, and Vogesella. PICRUSt analysis revealed that major functions are associated with the metabolism category. Additionally, metabolism related to amino acids, carbohydrates, energy generation, xenobiotics degradation, nitrogen, sulfate, and methane were prominent. Similarly, the predicted metabolisms by COG and KEGG were observed in the microbial communities of the marine sediments. To date, a comprehensive description of the microbial life with metabolic potential in these study sites has not been investigated. This study therefore significantly adds to our understanding of the microbiome and its functional attributes of marine sediments.
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Affiliation(s)
- Nirali M Raiyani
- UGC-CAS Department of Biosciences, Saurashtra University, Rajkot, 360 005, Gujarat, India
| | - Satya P Singh
- UGC-CAS Department of Biosciences, Saurashtra University, Rajkot, 360 005, Gujarat, India.
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Genomic Analysis Reveals Adaptation of Vibrio campbellii to the Hadal Ocean. Appl Environ Microbiol 2022; 88:e0057522. [PMID: 35916502 PMCID: PMC9397096 DOI: 10.1128/aem.00575-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The genus Vibrio is characterized by high metabolic flexibility and genome plasticity and is widely distributed in the ocean from euphotic layers to deep-sea environments. The relationship between genome features and environmental adaptation strategies of Vibrio has been extensively investigated in coastal environments, yet very little is known about their survival strategies in oligotrophic deep-sea. In this study, we compared genomes of five Vibrio campbellii strains isolated from the Mariana and Yap Trenches at different water depths, including two epipelagic strains and three hadopelagic strains, to identify genomic characteristics that facilitate survival in the deep sea. Genome streamlining is found in pelagic strains, such as smaller genome sizes, lower G+C contents, and higher gene densities, which might be caused by long-term residence in an oligotrophic environment. Phylogenetic results showed that these five Vibrio strains are clustered into two clades according to their collection depth. Indeed, hadopelagic isolates harbor more genes involved in amino acid metabolism and transport, cell wall/membrane/envelope biogenesis, and inorganic ion transport and metabolism through comparative genomics analysis. Specific macrolide export gene and more tellurite resistance genes present in hadopelagic strains by the annotation of antibiotic and metal resistance genes. In addition, several genes related to substrate degradation are enriched in hadopelagic strains, such as chitinase genes, neopullulanase genes, and biopolymer transporter genes. In contrast, epipelagic strains are unique in their capacity for assimilatory nitrate reduction. The genomic characteristics investigated here provide insights into how Vibrio adapts to the deep-sea environment through genomic evolution. IMPORTANCE With the development of deep-sea sampling technology, an increasing number of deep-sea Vibrio strains have been isolated, but the adaptation mechanism of these eutrophic Vibrio strains to the deep-sea environment is unclear. Here, our results show that the genome of pelagic Vibrio is streamlined to adapt to a long-term oligotrophic environment. Through a phylogenomic analysis, we find that genomic changes in marine Vibrio campbellii strains are related to water depth. Our data suggest that an increase in genes related to antibiotic resistance, degradation of macromolecular and refractory substrates, and utilization of rare ions is related to the adaptation of V. campbellii strains to adapt to hadal environments, and most of the increased genes were acquired by horizontal gene transfer. These findings may deepen our understanding of adaptation strategies of marine bacteria to the extreme environment in hadal zones.
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Naufal M, Wu JH, Shao YH. Glutamate Enhances Osmoadaptation of Anammox Bacteria under High Salinity: Genomic Analysis and Experimental Evidence. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11310-11322. [PMID: 35913201 DOI: 10.1021/acs.est.2c01104] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
An osmoprotectant that alleviates the bacterial osmotic stress can improve the bioreactor treatment of saline wastewater. However, proposed candidates are expensive, and osmoprotectants of anammox bacteria and their ecophysiological roles are not fully understood. In this study, a comparative analysis of 34 high-quality public metagenome-assembled genomes from anammox bacteria revealed two distinct groups of osmoadaptation. Candidatus Scalindua and Kuenenia share a close phylogenomic relation and osmoadaptation gene profile and have pathways for glutamate transport and metabolisms for enhanced osmoadaptation. The batch assay results demonstrated that the reduced Ca. Kuenenia activity in saline conditions was substantially alleviated with the addition and subsequent synergistic effects of potassium and glutamate. The operational test of two reactors demonstrated that the reduced anammox performance under brine conditions rapidly recovered by 35.7-43.1% as a result of glutamate treatment. The Ca. Kuenenia 16S rRNA and hydrazine gene expressions were upregulated significantly (p < 0.05), and the abundance increased by approximately 19.9%, with a decrease in dominant heterotrophs. These data demonstrated the effectiveness of glutamate in alleviating the osmotic stress of Ca. Kuenenia. This study provides genomic insight into group-specific osmoadaptation of anammox bacteria and can facilitate the precision management of anammox reactors under high salinity.
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Affiliation(s)
- Muhammad Naufal
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, East District, Tainan City 70101, Taiwan
| | - Jer-Horng Wu
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, East District, Tainan City 70101, Taiwan
| | - Yung-Hsien Shao
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, East District, Tainan City 70101, Taiwan
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10
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Coastal Transient Niches Shape the Microdiversity Pattern of a Bacterioplankton Population with Reduced Genomes. mBio 2022; 13:e0057122. [PMID: 35880883 PMCID: PMC9426536 DOI: 10.1128/mbio.00571-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Globally dominant marine bacterioplankton lineages are often limited in metabolic versatility, owing to their extensive genome reductions, and thus cannot take advantage of transient nutrient patches. It is therefore perplexing how the nutrient-poor bulk seawater sustains the pelagic streamlined lineages, each containing numerous populations. Here, we sequenced the genomes of 33 isolates of the recently discovered CHUG lineage (~2.6 Mbp), which have some of the smallest genomes in the globally abundant Roseobacter group (commonly over 4 Mbp). These genome-reduced bacteria were isolated from a transient habitat: seawater surrounding the brown alga, Sargassum hemiphyllum. Population genomic analyses showed that: (i) these isolates, despite sharing identical 16S rRNA genes, were differentiated into several genetically isolated populations through successive speciation events; (ii) only the first speciation event led to the genetic separation of both core and accessory genomes; and (iii) populations resulting from this event are differentiated at many loci involved in carbon utilization and oxygen respiration, corroborated by BiOLOG phenotype microarray assays and oxygen uptake kinetics experiments, respectively. These differentiated traits match well with the dynamic nature of the macroalgal seawater, in which the quantity and quality of carbon sources and the concentration of oxygen likely vary spatially and temporally, though other habitats, like fresh organic aggregates, cannot be ruled out. Our study implies that transient habitats in the overall nutrient-poor ocean can shape the microdiversity and population structure of genome-reduced bacterioplankton lineages.
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Schön ME, Martijn J, Vosseberg J, Köstlbacher S, Ettema TJG. The evolutionary origin of host association in the Rickettsiales. Nat Microbiol 2022; 7:1189-1199. [PMID: 35798888 PMCID: PMC9352585 DOI: 10.1038/s41564-022-01169-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 05/30/2022] [Indexed: 12/14/2022]
Abstract
The evolution of obligate host-association of bacterial symbionts and pathogens remains poorly understood. The Rickettsiales are an alphaproteobacterial order of obligate endosymbionts and parasites that infect a wide variety of eukaryotic hosts, including humans, livestock, insects and protists. Induced by their host-associated lifestyle, Rickettsiales genomes have undergone reductive evolution, leading to small, AT-rich genomes with limited metabolic capacities. Here we uncover eleven deep-branching alphaproteobacterial metagenome assembled genomes from aquatic environments, including data from the Tara Oceans initiative and other publicly available datasets, distributed over three previously undescribed Rickettsiales-related clades. Phylogenomic analyses reveal that two of these clades, Mitibacteraceae and Athabascaceae, branch sister to all previously sampled Rickettsiales. The third clade, Gamibacteraceae, branch sister to the recently identified ectosymbiotic ‘Candidatus Deianiraea vastatrix’. Comparative analyses indicate that the gene complement of Mitibacteraceae and Athabascaceae is reminiscent of that of free-living and biofilm-associated bacteria. Ancestral genome content reconstruction across the Rickettsiales species tree further suggests that the evolution of host association in Rickettsiales was a gradual process that may have involved the repurposing of a type IV secretion system. Phylogenomic analyses reveal novel environmental clades of Rickettsiales providing insights into their evolution from free-living to host-associated lifestyle.
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Affiliation(s)
- Max E Schön
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Joran Martijn
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.,Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.,Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Canada
| | - Julian Vosseberg
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.,Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Stephan Köstlbacher
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Thijs J G Ettema
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden. .,Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
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12
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Ma X, Johnson KB, Gu B, Zhang H, Li G, Huang X, Xia X. The in-situ release of algal bloom populations and the role of prokaryotic communities in their establishment and growth. WATER RESEARCH 2022; 219:118565. [PMID: 35597219 DOI: 10.1016/j.watres.2022.118565] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 05/03/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Harmful algal blooms (HABs) may quickly travel and inoculate new water bodies via currents and runoff in estuaries. The role of in-situ prokaryotic communities in the re-establishment and growth of inoculated algal blooms remains unknown. A novel on-board incubation experiment was employed to simulate the sudden surge of algal blooms to new estuarine waters and reveal possible outcomes. A dinoflagellate (Amphidinium carterae) and a diatom species (Thalassiosira weissflogii) which had bloomed in the Pearl River Estuary (PRE) area were cultured to bloom densities and reintroduced back into PRE natural seawaters. The diatom showed better adaptation ability to the new environment and increased significantly after the incubation. Simultaneously, particle-attached (PA) prokaryotic community structure was strongly influenced by adding of the diatom, with some opportunistic prokaryotes significantly enhanced in the diatom treatment. Whereas the dinoflagellate population did not increase following incubation, and their PA prokaryotic community showed no significant differences relative to the control. Metagenomic analyzes revealed that labile carbohydrates and organic nitrogen produced by the diatom contributed to the surge of certain PA prokaryotes. Genomic properties of a bacteria strain, which is affiliated with genus GMD16E07 (Planctomycetaceae) and comprised up to 50% of PA prokaryotes in the diatom treatment, was described here for the first time. Notably, the association of Planctomycetaceae and T. weissflogii likely represents symbiotic mutualism, with the diatom providing organic matter for Planctomycetaceae and the bacteria supplying vitamins and detoxifying nitriles and hydrogen peroxides in exchange. Therefore, the close association between Planctomycetaceae and T. weissflogii promoted the growth of both populations, and eventually facilitated the diatom bloom establishment.
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Affiliation(s)
- Xiao Ma
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), China
| | - Kevin B Johnson
- Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Bowei Gu
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Hao Zhang
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), China
| | - Gang Li
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), China
| | - Xiaoping Huang
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), China
| | - Xiaomin Xia
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), China.
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Olofsson M, Ferrer-González FX, Uchimiya M, Schreier JE, Holderman NR, Smith CB, Edison AS, Moran MA. Growth-stage-related shifts in diatom endometabolome composition set the stage for bacterial heterotrophy. ISME COMMUNICATIONS 2022; 2:28. [PMID: 37938663 PMCID: PMC9723723 DOI: 10.1038/s43705-022-00116-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/25/2022] [Accepted: 03/07/2022] [Indexed: 05/28/2023]
Abstract
Phytoplankton-derived metabolites fuel a large fraction of heterotrophic bacterial production in the global ocean, yet methodological challenges have limited our understanding of the organic molecules transferred between these microbial groups. In an experimental bloom study consisting of three heterotrophic marine bacteria growing together with the diatom Thalassiosira pseudonana, we concurrently measured diatom endometabolites (i.e., potential exometabolite supply) by nuclear magnetic resonance (NMR) spectroscopy and bacterial gene expression (i.e., potential exometabolite uptake) by metatranscriptomic sequencing. Twenty-two diatom endometabolites were annotated, with nine increasing in internal concentration in the late stage of the bloom, eight decreasing, and five showing no variation through the bloom progression. Some metabolite changes could be linked to shifts in diatom gene expression, as well as to shifts in bacterial community composition and their expression of substrate uptake and catabolism genes. Yet an overall low match indicated that endometabolome concentration was not a good predictor of exometabolite availability, and that complex physiological and ecological interactions underlie metabolite exchange. Six diatom endometabolites accumulated to higher concentrations in the bacterial co-cultures compared to axenic cultures, suggesting a bacterial influence on rates of synthesis or release of glutamate, arginine, leucine, 2,3-dihydroxypropane-1-sulfonate, glucose, and glycerol-3-phosphate. Better understanding of phytoplankton metabolite production, release, and transfer to assembled bacterial communities is key to untangling this nearly invisible yet pivotal step in ocean carbon cycling.
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Affiliation(s)
- Malin Olofsson
- Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, 750 57, Uppsala, Sweden
| | | | - Mario Uchimiya
- Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA
- Department of Biochemistry and Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA
| | - Jeremy E Schreier
- Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA
| | - Nicole R Holderman
- Department of Biochemistry and Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA
| | - Christa B Smith
- Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA
| | - Arthur S Edison
- Department of Biochemistry and Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA
| | - Mary Ann Moran
- Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA.
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14
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Interaction and Assembly of Bacterial Communities in High-Latitude Coral Habitat Associated Seawater. Microorganisms 2022; 10:microorganisms10030558. [PMID: 35336132 PMCID: PMC8955259 DOI: 10.3390/microorganisms10030558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/27/2022] [Accepted: 03/01/2022] [Indexed: 11/16/2022] Open
Abstract
Threatened by climate change and ocean warming, coral reef ecosystems have been shifting in geographic ranges toward a higher latitude area. The water-associated microbial communities and their potential role in primary production contribution are well studied in tropical coral reefs, but poorly defined in high-latitude coral habitats to date. In this study, amplicon sequencing of 16S rRNA and cbbL gene, co-occurrence network, and βNTI were used. The community structure of bacterial and carbon-fixation bacterial communities showed a significant difference between the center of coral, transitional, and non-coral area. Nitrite, DOC, pH, and coral coverage ratio significantly impacted the β-diversity of bacterial and carbon-fixation communities. The interaction of heterotrophs and autotrophic carbon-fixers was more complex in the bottom than in surface water. Carbon-fixers correlated with diverse heterotrophs in surface water but fewer lineages of heterotrophic taxa in the bottom. Bacterial community assembly showed an increase by deterministic process with decrease of coral coverage in bottom water, which may correlate with the gradient of nitrite and pH in the habitat. A deterministic process dominated the assembly of carbon-fixation bacterial community in surface water, while stochastic process dominated t the bottom. In conclusion, the structure and assembly of bacterial and carbon-fixer community were affected by multi-environmental variables in high-latitude coral habitat-associated seawater.
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15
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Yu Q, Yang J, Su W, Li T, Feng T, Li H. Heavy metals and microbiome are negligible drivers than mobile genetic elements in determining particle-attached and free-living resistomes in the Yellow River. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127564. [PMID: 34736202 DOI: 10.1016/j.jhazmat.2021.127564] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/27/2021] [Accepted: 10/18/2021] [Indexed: 06/13/2023]
Abstract
Suspended particles in water can shelter both microorganisms and contaminants. However, the emerging pollutants antibiotic resistance genes (ARGs) in free-living (FL) or particle-attached (PA) bacteria in aquatic environments are less explored. In this study, we compared the free-living and particle-attached ARGs during four seasons in the Yellow River using high-throughput quantitative PCR techniques and 16S rRNA gene sequencing. Our results demonstrated that both the free-living water and particles were dominated by tetracycline and beta-lactamase resistance genes. The PA-ARGs had a higher absolute abundance than FL-ARGs in the Yellow River, regardless of the season. Both PA-ARGs and FL-ARGs had the highest absolute abundance and diversity during winter. Mobile genetic elements (MGEs) were the dominant driver for both size-fractionated ARGs. However, the microbiome had less influence on PA-ARG profiles than the FL-ARG profiles, while the effects of the heavy metals on ARGs were negligible. The community assembly of both FL-ARG and PA-ARG can be explained by neutral processes. Several opportunistic pathogens (e.g., Escherichia coli) associated with human health exhibited a higher relative abundance in the particles than during a free-living lifestyle. Parts of these pathogens were potential ARG hosts. As such, it is important to monitor the ARGs and opportunistic pathogens from size-fractionated bacteria and develop targeted strategies to manage ARG dissemination and opportunistic pathogens to ensure public health.
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Affiliation(s)
- Qiaoling Yu
- School of Public Health, Lanzhou University, Lanzhou 730000, China
| | - Jiawei Yang
- School of Public Health, Lanzhou University, Lanzhou 730000, China
| | - Wanghong Su
- School of Public Health, Lanzhou University, Lanzhou 730000, China
| | - Tongtong Li
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Tianshu Feng
- School of Public Health, Lanzhou University, Lanzhou 730000, China
| | - Huan Li
- School of Public Health, Lanzhou University, Lanzhou 730000, China; Center for Grassland Microbiome, Lanzhou University, Lanzhou 730000, China.
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16
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Follett CL, Dutkiewicz S, Ribalet F, Zakem E, Caron D, Armbrust EV, Follows MJ. Trophic interactions with heterotrophic bacteria limit the range of Prochlorococcus. Proc Natl Acad Sci U S A 2022; 119:e2110993118. [PMID: 34983874 PMCID: PMC8764666 DOI: 10.1073/pnas.2110993118] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2021] [Indexed: 11/26/2022] Open
Abstract
Prochlorococcus is both the smallest and numerically most abundant photosynthesizing organism on the planet. While thriving in the warm oligotrophic gyres, Prochlorococcus concentrations drop rapidly in higher-latitude regions. Transect data from the North Pacific show the collapse occurring at a wide range of temperatures and latitudes (temperature is often hypothesized to cause this shift), suggesting an ecological mechanism may be at play. An often used size-based theory of phytoplankton community structure that has been incorporated into computational models correctly predicts the dominance of Prochlorococcus in the gyres, and the relative dominance of larger cells at high latitudes. However, both theory and computational models fail to explain the poleward collapse. When heterotrophic bacteria and predators that prey nonspecifically on both Prochlorococcus and bacteria are included in the theoretical framework, the collapse of Prochlorococcus occurs with increasing nutrient supplies. The poleward collapse of Prochlorococcus populations then naturally emerges when this mechanism of "shared predation" is implemented in a complex global ecosystem model. Additionally, the theory correctly predicts trends in both the abundance and mean size of the heterotrophic bacteria. These results suggest that ecological controls need to be considered to understand the biogeography of Prochlorococcus and predict its changes under future ocean conditions. Indirect interactions within a microbial network can be essential in setting community structure.
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Affiliation(s)
- Christopher L Follett
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139;
| | - Stephanie Dutkiewicz
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - François Ribalet
- School of Oceanography, University of Washington, Seattle, WA 98195
| | - Emily Zakem
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | - David Caron
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | | | - Michael J Follows
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
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17
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Diversity Distribution, Driving Factors and Assembly Mechanisms of Free-Living and Particle-Associated Bacterial Communities at a Subtropical Marginal Sea. Microorganisms 2021; 9:microorganisms9122445. [PMID: 34946047 PMCID: PMC8704526 DOI: 10.3390/microorganisms9122445] [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: 11/01/2021] [Revised: 11/21/2021] [Accepted: 11/24/2021] [Indexed: 01/04/2023] Open
Abstract
Free-living (FL) and particle-associated (PA) bacterioplankton communities play critical roles in biogeochemical cycles in the ocean. However, their community composition, assembly process and functions in the continental shelf and slope regions are poorly understood. Based on 16S rRNA gene amplicon sequencing, we investigated bacterial communities’ driving factors, assembly processes and functional potentials at a subtropical marginal sea. The bacterioplankton community showed specific distribution patterns with respect to lifestyle (free living vs. particle associated), habitat (slope vs. shelf) and depth (surface vs. DCM and Bottom). Salinity and water temperature were the key factors modulating turnover in the FL community, whereas nitrite, silicate and phosphate were the key factors for the PA community. Model analyses revealed that stochastic processes outweighed deterministic processes and had stronger influences on PA than FL. Homogeneous selection (Hos) was more responsible for the assembly and turnover of FL, while drift and dispersal limitation contributed more to the assembly of PA. Importantly, the primary contributor to Hos in PA was Gammaproteobacteria:Others, whereas that in FL was Cyanobacteria:Bin6. Finally, the PICRUSt2 analysis indicated that the potential metabolisms of carbohydrates, cofactors, amino acids, terpenoids, polyketides, lipids and antibiotic resistance were markedly enriched in PA than FL.
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18
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Zhang H, Sun Y, Zeng Q, Crowe SA, Luo H. Snowball Earth, population bottleneck and Prochlorococcus evolution. Proc Biol Sci 2021; 288:20211956. [PMID: 34784770 PMCID: PMC8596011 DOI: 10.1098/rspb.2021.1956] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/26/2021] [Indexed: 11/12/2022] Open
Abstract
Prochlorococcus are the most abundant photosynthetic organisms in the modern ocean. A massive DNA loss event occurred in their early evolutionary history, leading to highly reduced genomes in nearly all lineages, as well as enhanced efficiency in both nutrient uptake and light absorption. The environmental landscape that shaped this ancient genome reduction, however, remained unknown. Through careful molecular clock analyses, we established that this Prochlorococcus genome reduction occurred during the Neoproterozoic Snowball Earth climate catastrophe. The lethally low temperature and exceedingly dim light during the Snowball Earth event would have inhibited Prochlorococcus growth and proliferation, and caused severe population bottlenecks. These bottlenecks are recorded as an excess of deleterious mutations accumulated across genomic regions and inherited by descendant lineages. Prochlorococcus adaptation to extreme environmental conditions during Snowball Earth intervals can be inferred by tracing the evolutionary paths of genes that encode key metabolic potential. Key metabolic innovation includes modified lipopolysaccharide structure, strengthened peptidoglycan biosynthesis, the replacement of a sophisticated circadian clock with an hourglass-like mechanism that resets daily for dim light adaption and the adoption of ammonia diffusion as an efficient membrane transporter-independent mode of nitrogen acquisition. In this way, the Neoproterozoic Snowball Earth event may have altered the physiological characters of Prochlorococcus, shaping their ecologically vital role as the most abundant primary producers in the modern oceans.
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Affiliation(s)
- Hao Zhang
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518000, People's Republic of China
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
| | - Ying Sun
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
| | - Qinglu Zeng
- Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR
| | - Sean A. Crowe
- Department of Earth Sciences, School of Biological Sciences, and Swire Institute for Marine Science (SWIMS), University of Hong Kong, Pokfulam Road, Hong Kong SAR
| | - Haiwei Luo
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518000, People's Republic of China
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
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19
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Liang KYH, Orata FD, Boucher YF, Case RJ. Roseobacters in a Sea of Poly- and Paraphyly: Whole Genome-Based Taxonomy of the Family Rhodobacteraceae and the Proposal for the Split of the "Roseobacter Clade" Into a Novel Family, Roseobacteraceae fam. nov. Front Microbiol 2021; 12:683109. [PMID: 34248901 PMCID: PMC8267831 DOI: 10.3389/fmicb.2021.683109] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/27/2021] [Indexed: 11/13/2022] Open
Abstract
The family Rhodobacteraceae consists of alphaproteobacteria that are metabolically, phenotypically, and ecologically diverse. It includes the roseobacter clade, an informal designation, representing one of the most abundant groups of marine bacteria. The rapid pace of discovery of novel roseobacters in the last three decades meant that the best practice for taxonomic classification, a polyphasic approach utilizing phenotypic, genotypic, and phylogenetic characteristics, was not always followed. Early efforts for classification relied heavily on 16S rRNA gene sequence similarity and resulted in numerous taxonomic inconsistencies, with several poly- and paraphyletic genera within this family. Next-generation sequencing technologies have allowed whole-genome sequences to be obtained for most type strains, making a revision of their taxonomy possible. In this study, we performed whole-genome phylogenetic and genotypic analyses combined with a meta-analysis of phenotypic data to review taxonomic classifications of 331 type strains (under 119 genera) within the Rhodobacteraceae family. Representatives of the roseobacter clade not only have different environmental adaptions from other Rhodobacteraceae isolates but were also found to be distinct based on genomic, phylogenetic, and in silico-predicted phenotypic data. As such, we propose to move this group of bacteria into a new family, Roseobacteraceae fam. nov. In total, reclassifications resulted to 327 species and 128 genera, suggesting that misidentification is more problematic at the genus than species level. By resolving taxonomic inconsistencies of type strains within this family, we have established a set of coherent criteria based on whole-genome-based analyses that will help guide future taxonomic efforts and prevent the propagation of errors.
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Affiliation(s)
- Kevin Y H Liang
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Fabini D Orata
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Yann F Boucher
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Saw Swee Hock School of Public Health, National University Singapore, Singapore, Singapore
| | - Rebecca J Case
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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20
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Feng X, Chu X, Qian Y, Henson MW, Lanclos VC, Qin F, Barnes S, Zhao Y, Thrash JC, Luo H. Mechanisms driving genome reduction of a novel Roseobacter lineage. ISME JOURNAL 2021; 15:3576-3586. [PMID: 34145391 DOI: 10.1038/s41396-021-01036-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 06/01/2021] [Accepted: 06/04/2021] [Indexed: 01/21/2023]
Abstract
Members of the marine Roseobacter group are key players in the global carbon and sulfur cycles. While over 300 species have been described, only 2% possess reduced genomes (mostly 3-3.5 Mbp) compared to an average roseobacter (>4 Mbp). These taxonomic minorities are phylogenetically diverse but form a Pelagic Roseobacter Cluster (PRC) at the genome content level. Here, we cultivated eight isolates constituting a novel Roseobacter lineage which we named 'CHUG'. Metagenomic and metatranscriptomic read recruitment analyses showed that CHUG members are globally distributed and active in marine pelagic environments. CHUG members possess some of the smallest genomes (~2.6 Mb) among all known roseobacters, but they do not exhibit canonical features of typical bacterioplankton lineages theorized to have undergone genome streamlining processes, like higher coding density, fewer paralogues and rarer pseudogenes. While CHUG members form a genome content cluster with traditional PRC members, they show important differences. Unlike other PRC members, neither the relative abundances of CHUG members nor their relative gene expression levels are correlated with chlorophyll a concentration across the global samples. CHUG members cannot utilize most phytoplankton-derived metabolites or synthesize vitamin B12, a key metabolite mediating the roseobacter-phytoplankton interactions. This combination of features is evidence for the hypothesis that CHUG members may have evolved a free-living lifestyle decoupled from phytoplankton. This ecological transition was accompanied by the loss of signature genes involved in roseobacter-phytoplankton symbiosis, suggesting that relaxation of purifying selection owing to lifestyle shift is likely an important driver of genome reduction in CHUG.
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Affiliation(s)
- Xiaoyuan Feng
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, SAR, Hong Kong.,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Xiao Chu
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, SAR, Hong Kong
| | - Yang Qian
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, SAR, Hong Kong
| | - Michael W Henson
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.,Department of Geophysical Sciences, University of Chicago, Chicago, IL, USA
| | - V Celeste Lanclos
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Fang Qin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Shelby Barnes
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Yanlin Zhao
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - J Cameron Thrash
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Haiwei Luo
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, SAR, Hong Kong. .,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China.
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21
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Norris N, Levine NM, Fernandez VI, Stocker R. Mechanistic model of nutrient uptake explains dichotomy between marine oligotrophic and copiotrophic bacteria. PLoS Comput Biol 2021; 17:e1009023. [PMID: 34010286 PMCID: PMC8168909 DOI: 10.1371/journal.pcbi.1009023] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 06/01/2021] [Accepted: 04/28/2021] [Indexed: 11/24/2022] Open
Abstract
Marine bacterial diversity is immense and believed to be driven in part by trade-offs in metabolic strategies. Here we consider heterotrophs that rely on organic carbon as an energy source and present a molecular-level model of cell metabolism that explains the dichotomy between copiotrophs—which dominate in carbon-rich environments—and oligotrophs—which dominate in carbon-poor environments—as the consequence of trade-offs between nutrient transport systems. While prototypical copiotrophs, like Vibrios, possess numerous phosphotransferase systems (PTS), prototypical oligotrophs, such as SAR11, lack PTS and rely on ATP-binding cassette (ABC) transporters, which use binding proteins. We develop models of both transport systems and use them in proteome allocation problems to predict the optimal nutrient uptake and metabolic strategy as a function of carbon availability. We derive a Michaelis–Menten approximation of ABC transport, analytically demonstrating how the half-saturation concentration is a function of binding protein abundance. We predict that oligotrophs can attain nanomolar half-saturation concentrations using binding proteins with only micromolar dissociation constants and while closely matching transport and metabolic capacities. However, our model predicts that this requires large periplasms and that the slow diffusion of the binding proteins limits uptake. Thus, binding proteins are critical for oligotrophic survival yet severely constrain growth rates. We propose that this trade-off fundamentally shaped the divergent evolution of oligotrophs and copiotrophs. Marine bacteria utilize carbon as a building block and an energy source and thus exert an important control on the amount of carbon that is sequestered in the ocean versus respired into the atmosphere. They use a spectrum of strategies to consume carbon: while copiotrophic bacteria dominate in nutrient-rich environments, oligotrophic bacteria dominate in nutrient-poor environments and are typically smaller, nonmotile, and slower growing. Yet the paragon oligotroph SAR11 is the planet’s most abundant organism. Despite this, most of our understanding of bacteria derives from research on copiotrophs. Here we use molecular-level models to understand how an oligotroph’s physiology enables it to outperform copiotrophs in nutrient-poor but not in nutrient-rich environments. We contrast copiotrophs’ prevalent method of sugar transport with oligotrophs’ reliance on binding proteins, which trap nutrients in the periplasm. Binding proteins allow cells to attain affinities that are much higher than the transport proteins’ intrinsic affinities. However, our model predicts that attaining such high affinities requires large periplasms with high abundances of the slowly diffusing binding proteins, which precludes high growth rates. By quantifying the benefits and costs of binding proteins, we provide a mechanistic explanation for the divergent evolution of oligotrophs and copiotrophs.
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Affiliation(s)
- Noele Norris
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, United States of America
- Department of Biological Sciences, University of Southern California, Los Angeles, United States of America
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zürich, Zürich, Switzerland
- * E-mail: (NN); (RS)
| | - Naomi M. Levine
- Department of Biological Sciences, University of Southern California, Los Angeles, United States of America
| | - Vicente I. Fernandez
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zürich, Zürich, Switzerland
| | - Roman Stocker
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zürich, Zürich, Switzerland
- * E-mail: (NN); (RS)
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22
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Silvano E, Yang M, Wolterink M, Giebel HA, Simon M, Scanlan DJ, Zhao Y, Chen Y. Lipidomic Analysis of Roseobacters of the Pelagic RCA Cluster and Their Response to Phosphorus Limitation. Front Microbiol 2021; 11:552135. [PMID: 33408696 PMCID: PMC7779409 DOI: 10.3389/fmicb.2020.552135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 11/25/2020] [Indexed: 01/15/2023] Open
Abstract
The marine roseobacter-clade affiliated cluster (RCA) represents one of the most abundant groups of bacterioplankton in the global oceans, particularly in temperate and sub-polar regions. They play a key role in the biogeochemical cycling of various elements and are important players in oceanic climate-active trace gas metabolism. In contrast to copiotrophic roseobacter counterparts such as Ruegeria pomeroyi DSS-3 and Phaeobacter sp. MED193, RCA bacteria are truly pelagic and have smaller genomes. We have previously shown that RCA bacteria do not appear to encode the PlcP-mediated lipid remodeling pathway, whereby marine heterotrophic bacteria remodel their membrane lipid composition in response to phosphorus (P) stress by substituting membrane glycerophospholipids with alternative glycolipids or betaine lipids. In this study, we report lipidomic analysis of six RCA isolates. In addition to the commonly found glycerophospholipids such as phosphatidylglycerol (PG) and phosphatidylethanolamine (PE), RCA bacteria synthesize a relatively uncommon phospholipid, acylphosphatidylglycerol, which is not found in copiotrophic roseobacters. Instead, like the abundant SAR11 clade, RCA bacteria upregulate ornithine lipid biosynthesis in response to P stress, suggesting a key role of this aminolipid in the adaptation of marine heterotrophs to oceanic nutrient limitation.
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Affiliation(s)
- Eleonora Silvano
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Mingyu Yang
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Mathias Wolterink
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg, Germany
| | - Helge-Ansgar Giebel
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg, Germany
| | - Meinhard Simon
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg, Germany
| | - David J Scanlan
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Yanlin Zhao
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yin Chen
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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23
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Martijn J, Schön ME, Lind AE, Vosseberg J, Williams TA, Spang A, Ettema TJG. Hikarchaeia demonstrate an intermediate stage in the methanogen-to-halophile transition. Nat Commun 2020; 11:5490. [PMID: 33127909 PMCID: PMC7599335 DOI: 10.1038/s41467-020-19200-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 10/01/2020] [Indexed: 01/09/2023] Open
Abstract
Halobacteria (henceforth: Haloarchaea) are predominantly aerobic halophiles that are thought to have evolved from anaerobic methanogens. This remarkable transformation most likely involved an extensive influx of bacterial genes. Whether it entailed a single massive transfer event or a gradual stream of transfers remains a matter of debate. To address this, genomes that descend from methanogen-to-halophile intermediates are necessary. Here, we present five such near-complete genomes of Marine Group IV archaea (Hikarchaeia), the closest known relatives of Haloarchaea. Their inclusion in gene tree-aware ancestral reconstructions reveals an intermediate stage that had already lost a large number of genes, including nearly all of those involved in methanogenesis and the Wood-Ljungdahl pathway. In contrast, the last Haloarchaea common ancestor gained a large number of genes and expanded its aerobic respiration and salt/UV resistance gene repertoire. Our results suggest that complex and gradual patterns of gain and loss shaped the methanogen-to-halophile transition.
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Affiliation(s)
- Joran Martijn
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Canada
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Max E Schön
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Anders E Lind
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Julian Vosseberg
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
- Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Anja Spang
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, Den Burg, The Netherlands
| | - Thijs J G Ettema
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
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24
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Chu X, Li S, Wang S, Luo D, Luo H. Gene loss through pseudogenization contributes to the ecological diversification of a generalist Roseobacter lineage. ISME JOURNAL 2020; 15:489-502. [PMID: 32999421 DOI: 10.1038/s41396-020-00790-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 09/13/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022]
Abstract
Ecologically relevant genes generally show patchy distributions among related bacterial genomes. This is commonly attributed to lateral gene transfer, whereas the opposite mechanism-gene loss-has rarely been explored. Pseudogenization is a major mechanism underlying gene loss, and pseudogenes are best characterized by comparing closely related genomes because of their short life spans. To explore the role of pseudogenization in microbial ecological diversification, we apply rigorous methods to characterize pseudogenes in the 279 newly sequenced Ruegeria isolates of the globally abundant Roseobacter group collected from two typical coastal habitats in Hong Kong, the coral Platygyra acuta and the macroalga Sargassum hemiphyllum. Pseudogenes contribute to ~16% of the accessory genomes of these strains. Ancestral state reconstruction reveals that many pseudogenization events are correlated with ancestral niche shifts. Specifically, genes related to resource scavenging and energy acquisition were often pseudogenized when roseobacters inhabiting carbon-limited and energy-poor coral skeleton switched to other resource-richer niches. For roseobacters inhabiting the macroalgal niches, genes for nitrogen regulation and carbohydrate utilization were important but became dispensable upon shift to coral skeleton where nitrate is abundant but carbohydrates are less available. Whereas low-energy-demanding secondary transporters are more favorable in coral skeleton, ATP-driven primary transporters are preferentially kept in the energy-replete macroalgal niches. Moreover, a large proportion of these families mediate organismal interactions, suggesting their rapid losses by pseudogenization as a potential response to host and niche shift. These findings illustrate an important role of pseudogenization in shaping genome content and driving ecological diversification of marine roseobacters.
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Affiliation(s)
- Xiao Chu
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
| | - Siyao Li
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
| | - Sishuo Wang
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
| | - Danli Luo
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
| | - Haiwei Luo
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR. .,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, 518000, China.
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25
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Abstract
The rise in the availability of bacterial genomes defines a need for synthesis: abstracting from individual taxa, to see larger patterns of bacterial lifestyles across systems. A key concept for such synthesis in ecology is the niche, the set of capabilities that enables a population's persistence and defines its impact on the environment. The set of possible niches forms the niche space, a conceptual space delineating ways in which persistence in a system is possible. Here we use manifold learning to map the space of metabolic networks representing thousands of bacterial genera. The results suggest a metabolic niche space comprising a collection of discrete clusters and branching manifolds, which constitute strategies spanning life in different habitats and hosts. We further demonstrate that communities from similar ecosystem types map to characteristic regions of this functional coordinate system, permitting coarse-graining of microbiomes in terms of ecological niches that may be filled.
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Affiliation(s)
- Ashkaan K Fahimipour
- University of California Davis, Department of Computer Science, 1 Shields Ave, Davis, CA, 95616, USA.
- National Oceanic and Atmospheric Administration, Southwest Fisheries Science Center, 110 McAllister Way, Santa Cruz, CA, 95060, USA.
| | - Thilo Gross
- University of California Davis, Department of Computer Science, 1 Shields Ave, Davis, CA, 95616, USA
- Alfred-Wegener-Institut Helmholtz-Centre for Marine and Polar Research, AM Handelshafen 12, Bremerhaven, 27570, Germany
- Helmholtz Institute for Functional Marine Biodiversity (HIFMB), Ammerländer Heerstrasse 231, 26129, Oldenburg, Germany
- University of Oldenburg, Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky Str. 9 - 11, 26129, Oldenburg, Germany
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26
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Hu Y, Xie G, Jiang X, Shao K, Tang X, Gao G. The Relationships Between the Free-Living and Particle-Attached Bacterial Communities in Response to Elevated Eutrophication. Front Microbiol 2020; 11:423. [PMID: 32269552 PMCID: PMC7109266 DOI: 10.3389/fmicb.2020.00423] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 02/27/2020] [Indexed: 11/13/2022] Open
Abstract
Exploring the relationships between free-living (FL) and particle-attached (PA) bacterial communities can provide insight into their connectivity and the partitioning of biogeochemical processes, which is crucial to understanding the elemental cycles and metabolic pathways in aquatic ecosystems. However, there is still intense debate about that whether FL and PA fractions have the same assemblage. To address this issue, we investigated the extent of similarity between FL and PA bacterial communities along the environmental gradients in Lake Wuli, China. Our results revealed that the west Lake Wuli was slightly eutrophic and the east lake was moderately and highly eutrophic. The alpha-diversity of the FL bacterial communities was significantly lower than that of the PA fraction in the west lake, whereas the alpha-diversity of the two fractions was comparable in the east lake. The beta-diversity of both communities significantly differed in the west lake, whereas it resembled that in the east lake. Moreover, functional prediction analysis highlighted the significantly larger differences of metabolic functions between the FL and PA fractions in the west lake than in the east lake. Suspended particles and carbon resource promote the similarity between the FL and PA fractions. Collectively, our result reveals a convergent succession of aquatic communities along the eutrophic gradient, highlighting that the connectivity between FL and PA bacterial communities is nutrient related.
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Affiliation(s)
- Yang Hu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Guijuan Xie
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
- Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Beijing, China
| | - Xingyu Jiang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
- Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Beijing, China
| | - Keqiang Shao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Xiangming Tang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Guang Gao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
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27
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Wang Y, Casaburi G, Lin W, Li Y, Wang F, Pan Y. Genomic evidence of the illumination response mechanism and evolutionary history of magnetotactic bacteria within the Rhodospirillaceae family. BMC Genomics 2019; 20:407. [PMID: 31117953 PMCID: PMC6532209 DOI: 10.1186/s12864-019-5751-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 04/29/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Magnetotactic bacteria (MTB) are ubiquitous in natural aquatic environments. MTB can produce intracellular magnetic particles, navigate along geomagnetic field, and respond to light. However, the potential mechanism by which MTB respond to illumination and their evolutionary relationship with photosynthetic bacteria remain elusive. RESULTS We utilized genomes of the well-sequenced genus Magnetospirillum, including the newly sequenced MTB strain Magnetospirillum sp. XM-1 to perform a comprehensive genomic comparison with phototrophic bacteria within the family Rhodospirillaceae regarding the illumination response mechanism. First, photoreceptor genes were identified in the genomes of both MTB and phototrophic bacteria in the Rhodospirillaceae family, but no photosynthesis genes were found in the MTB genomes. Most of the photoreceptor genes in the MTB genomes from this family encode phytochrome-domain photoreceptors that likely induce red/far-red light phototaxis. Second, illumination also causes damage within the cell, and in Rhodospirillaceae, both MTB and phototrophic bacteria possess complex but similar sets of response and repair genes, such as oxidative stress response, iron homeostasis and DNA repair system genes. Lastly, phylogenomic analysis showed that MTB cluster closely with phototrophic bacteria in this family. One photoheterotrophic genus, Phaeospirillum, clustered within and displays high genomic similarity with Magnetospirillum. Moreover, the phylogenetic tree topologies of magnetosome synthesis genes in MTB and photosynthesis genes in phototrophic bacteria from the Rhodospirillaceae family were reasonably congruent with the phylogenomic tree, suggesting that these two traits were most likely vertically transferred during the evolution of their lineages. CONCLUSION Our new genomic data indicate that MTB and phototrophic bacteria within the family Rhodospirillaceae possess diversified photoreceptors that may be responsible for phototaxis. Their genomes also contain comprehensive stress response genes to mediate the negative effects caused by illumination. Based on phylogenetic studies, most of MTB and phototrophic bacteria in the Rhodospirillaceae family evolved vertically with magnetosome synthesis and photosynthesis genes. The ancestor of Rhodospirillaceae was likely a magnetotactic phototrophic bacteria, however, gain or loss of magnetotaxis and phototrophic abilities might have occurred during the evolution of ancestral Rhodospirillaceae lineages.
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Affiliation(s)
- Yinzhao Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China. .,Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Giorgio Casaburi
- Departments of Microbiology and Cell Science, Space Life Sciences Laboratory, University of Florida, Merritt Island, FL, 32953, USA
| | - Wei Lin
- Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Ying Li
- State Key Laboratory of Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Fengping Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yongxin Pan
- Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
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28
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Liu M, Liu L, Chen H, Yu Z, Yang JR, Xue Y, Huang B, Yang J. Community dynamics of free-living and particle-attached bacteria following a reservoir Microcystis bloom. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 660:501-511. [PMID: 30640117 DOI: 10.1016/j.scitotenv.2018.12.414] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 12/27/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
The composition of microbial communities can vary at the microspatial scale between free-living (FL) and particle-attached (PA) niches. However, it remains unclear how FL and PA bacterial communities respond to cyanobacterial blooms across water depths. Here, we examined the community dynamics of the FL (0.2-3 μm) and PA (>3 μm) bacterioplankton based on 16S rRNA gene high-throughput sequencing in a subtropical stratified reservoir under Microcystis aeruginosa bloom and non-bloom conditions. Both FL and PA bacterioplankton communities showed different responses in alpha- and beta-diversities to the bloom, suggesting the idea that the responses of bacterial community could depend on lifestyle. Specifically, abundant PA subcommunities showed a greater variation between bloom and non-bloom groups than abundant FL ones. In contrast, rare FL subcommunities exhibited a stronger response to water depth than rare PA ones. Furthermore, the rare taxa exhibited a preference for PA status, shaped and stimulated by the M. aeruginosa bloom. Our analyses also showed that PA bacterial communities were generally more diverse and appeared to be more responsive to routinely measured environmental variables than FL bacteria. Microcystis blooms had a facilitative influence on specific bacteria by mediating the transitions from free-living to particle-attached lifestyles. Altogether, these findings highlight the importance of bacterial lifestyle and abundance in understanding the dynamics of microbial community in cyanobacterial bloom aquatic ecosystem.
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Affiliation(s)
- Min Liu
- Aquatic Ecohealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China; College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Lemian Liu
- Aquatic Ecohealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Technical Innovation Service Platform for High Value and High Quality Utilization of Marine Organism, Fuzhou University, Fuzhou 350108, China
| | - Huihuang Chen
- Aquatic Ecohealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Zheng Yu
- Aquatic Ecohealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Department of Chemical Engineering, University of Washington, Seattle, WA 98105, USA
| | - Jun R Yang
- Aquatic Ecohealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Engineering Research Center of Ecology and Agricultural Use of Wetland, College of Agriculture, Yangtze University, Jingzhou 434025, China
| | - Yuanyuan Xue
- Aquatic Ecohealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China; College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Bangqin Huang
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Jun Yang
- Aquatic Ecohealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
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29
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Andrei AŞ, Salcher MM, Mehrshad M, Rychtecký P, Znachor P, Ghai R. Niche-directed evolution modulates genome architecture in freshwater Planctomycetes. THE ISME JOURNAL 2019; 13:1056-1071. [PMID: 30610231 PMCID: PMC6461901 DOI: 10.1038/s41396-018-0332-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 11/22/2018] [Accepted: 11/29/2018] [Indexed: 11/08/2022]
Abstract
Freshwater environments teem with microbes that do not have counterparts in culture collections or genetic data available in genomic repositories. Currently, our apprehension of evolutionary ecology of freshwater bacteria is hampered by the difficulty to establish organism models for the most representative clades. To circumvent the bottlenecks inherent to the cultivation-based techniques, we applied ecogenomics approaches in order to unravel the evolutionary history and the processes that drive genome architecture in hallmark freshwater lineages from the phylum Planctomycetes. The evolutionary history inferences showed that sediment/soil Planctomycetes transitioned to aquatic environments, where they gave rise to new freshwater-specific clades. The most abundant lineage was found to have the most specialised lifestyle (increased regulatory genetic circuits, metabolism tuned for mineralization of proteinaceous sinking aggregates, psychrotrophic behaviour) within the analysed clades and to harbour the smallest freshwater Planctomycetes genomes, highlighting a genomic architecture shaped by niche-directed evolution (through loss of functions and pathways not needed in the newly acquired freshwater niche).
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Affiliation(s)
- Adrian-Ştefan Andrei
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre CAS, Na Sádkách 702/7, 370 05 České Budějovice, Czech Republic.
| | - Michaela M Salcher
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre CAS, Na Sádkách 702/7, 370 05 České Budějovice, Czech Republic
- Limnological Station, Institute of Plant and Microbial Biology, University of Zurich, Seestrasse 187, 8802, Kilchberg, Switzerland
| | - Maliheh Mehrshad
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre CAS, Na Sádkách 702/7, 370 05 České Budějovice, Czech Republic
| | - Pavel Rychtecký
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre CAS, Na Sádkách 702/7, 370 05 České Budějovice, Czech Republic
| | - Petr Znachor
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre CAS, Na Sádkách 702/7, 370 05 České Budějovice, Czech Republic
| | - Rohit Ghai
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre CAS, Na Sádkách 702/7, 370 05 České Budějovice, Czech Republic.
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30
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Abstract
The streamlining hypothesis is usually used to explain the genomic reduction events in free-living bacteria like SAR11. However, we find that the genomic reduction phenomenon in the bacterial genus Idiomarina is different from that in SAR11. Therefore, we propose a new hypothesis to explain genomic reduction in this genus based on trophic specialization that could result in genomic reduction, which would be not uncommon in nature. Not only can the trophic specialization hypothesis explain the genomic reduction in the genus Idiomarina, but it also sheds new light on our understanding of the genomic reduction processes in other free-living bacterial lineages. The streamlining hypothesis is generally used to explain the genomic reduction events related to the small genome size of free-living bacteria like marine bacteria SAR11. However, our current understanding of the correlation between bacterial genome size and environmental adaptation relies on too few species. It is still unclear whether there are other paths leading to genomic reduction in free-living bacteria. The genome size of marine free-living bacteria of the genus Idiomarina belonging to the order Alteromonadales (Gammaproteobacteria) is much smaller than the size of related genomes from bacteria in the same order. Comparative genomic and physiological analyses showed that the genomic reduction pattern in this genus is different from that of the classical SAR11 lineage. Genomic reduction reconstruction and substrate utilization profile showed that Idiomarina spp. lost a large number of genes related to carbohydrate utilization, and instead they specialized on using proteinaceous resources. Here we propose a new hypothesis to explain genomic reduction in this genus; we propose that trophic specialization increasing the metabolic efficiency for using one kind of substrate but reducing the substrate utilization spectrum could result in bacterial genomic reduction, which would be not uncommon in nature. This hypothesis was further tested in another free-living genus, Kangiella, which also shows dramatic genomic reduction. These findings highlight that trophic specialization is potentially an important path leading to genomic reduction in some marine free-living bacteria, which is distinct from the classical lineages like SAR11.
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31
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Cho BC, Hardies SC, Jang GI, Hwang CY. Complete genome of streamlined marine actinobacterium Pontimonas salivibrio strain CL-TW6 T adapted to coastal planktonic lifestyle. BMC Genomics 2018; 19:625. [PMID: 30134835 PMCID: PMC6106888 DOI: 10.1186/s12864-018-5019-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 08/14/2018] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Pontimonas salivibrio strain CL-TW6T (=KCCM 90105 = JCM18206) was characterized as the type strain of a new genus within the Actinobacterial family Microbacteriaceae. It was isolated from a coastal marine environment in which members of Microbactericeae have not been previously characterized. RESULTS The genome of P. salivibrio CL-TW6T was a single chromosome of 1,760,810 bp. Genomes of this small size are typically found in bacteria growing slowly in oligotrophic zones and said to be streamlined. Phylogenetic analysis showed it to represent a lineage originating in the Microbacteriaceae radiation occurring before the snowball Earth glaciations, and to have a closer relationship with some streamlined bacteria known through metagenomic data. Several genomic characteristics typical of streamlined bacteria are found: %G + C is lower than non-streamlined members of the phylum; there are a minimal number of rRNA and tRNA genes, fewer paralogs in most gene families, and only two sigma factors; there is a noticeable absence of some nonessential metabolic pathways, including polyketide synthesis and catabolism of some amino acids. There was no indication of any phage genes or plasmids, however, a system of active insertion elements was present. P. salivibrio appears to be unusual in having polyrhamnose-based cell wall oligosaccharides instead of mycolic acid or teichoic acid-based oligosaccharides. Oddly, it conducts sulfate assimilation apparently for sulfating cell wall components, but not for synthesizing amino acids. One gene family it has more of, rather than fewer of, are toxin/antitoxin systems, which are thought to down-regulate growth during nutrient deprivation or other stressful conditions. CONCLUSIONS Because of the relatively small number of paralogs and its relationship to the heavily characterized Mycobacterium tuberculosis, we were able to heavily annotate the genome of P. salivibrio CL-TW6T. Its streamlined status and relationship to streamlined metagenomic constructs makes it an important reference genome for study of the streamlining concept. The final evolutionary trajectory of CL-TW6 T was to adapt to growth in a non-oligotrophic coastal zone. To understand that adaptive process, we give a thorough accounting of gene content, contrasting with both oligotrophic streamlined bacteria and large genome bacteria, and distinguishing between genes derived by vertical and horizontal descent.
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Affiliation(s)
- Byung Cheol Cho
- Microbial Oceanography Laboratory, School of Earth and Environmental Sciences and Research Institute of Oceanography, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Stephen C. Hardies
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio, TX USA
| | - Gwang Il Jang
- Microbial Oceanography Laboratory, School of Earth and Environmental Sciences and Research Institute of Oceanography, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
- Division of Life Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
| | - Chung Yeon Hwang
- Division of Life Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
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32
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Kieft B, Li Z, Bryson S, Crump BC, Hettich R, Pan C, Mayali X, Mueller RS. Microbial Community Structure-Function Relationships in Yaquina Bay Estuary Reveal Spatially Distinct Carbon and Nitrogen Cycling Capacities. Front Microbiol 2018; 9:1282. [PMID: 29963029 PMCID: PMC6010575 DOI: 10.3389/fmicb.2018.01282] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/25/2018] [Indexed: 12/11/2022] Open
Abstract
Linking microbial community structure to ecological processes requires understanding of the functional roles among individual populations and the factors that influence their distributions. These structure–function relationships are particularly difficult to disentangle in estuaries, due to highly variable physico-chemical conditions. Yet, examining microbe-mediated turnover of resources in these “bioreactor” ecosystems is critical for understanding estuarine ecology. In this study, a combined metagenomics and metaproteomics approach was used to show that the unequal distribution of microbial populations across the Yaquina Bay estuary led to a habitat-specific taxonomic and functional structure and a clear spatial distribution in microbe-mediated capacities for cycling of carbon and nitrogen. For example, size-fractionation revealed that communities inhabiting suspended particulate material encoded more diverse types of metabolisms (e.g., fermentation and denitrification) than those with a planktonic lifestyle, suggesting that the metabolic reactions can differ between size fractions of the same parcel of an estuarine water column. Similarly, communities inhabiting oligotrophic conditions in the lower estuary were enriched in genes involved in central carbon metabolism (e.g., TCA cycle), while communities in the upper estuary were enriched in genes typical of copiotrophic populations (e.g., cell growth, cell division). Integrating gene and protein data revealed that abundant populations of Flavobacteriales and Rhodobacterales encoded similar genomic functions, yet differed significantly in protein expression, dedicating a large proportion of their respective proteomes to rapid growth and division versus metabolic versatility and resource acquisition. This suggested potentially distinct life-strategies between these two co-occurring lineages and was concomitant with differing patterns of positive evolutionary selection on their encoded genes. Microbial communities and their functions across Yaquina Bay appear to be structured by population-level habitat preferences, resulting in spatially distinct elemental cycling, while within each community, forces such as competitive exclusion and evolutionary selection influence species life-strategies and may help maintain microbial diversity.
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Affiliation(s)
- Brandon Kieft
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Zhou Li
- Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Samuel Bryson
- Department of Civil and Environmental Engineering, The University of Washington, Seattle, WA, United States
| | - Byron C Crump
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States
| | - Robert Hettich
- Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Chongle Pan
- Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Xavier Mayali
- Lawrence Livermore National Laboratory, U.S. Department of Energy, Livermore, CA, United States
| | - Ryan S Mueller
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
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33
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Silveira CB, Cavalcanti GS, Walter JM, Silva-Lima AW, Dinsdale EA, Bourne DG, Thompson CC, Thompson FL. Microbial processes driving coral reef organic carbon flow. FEMS Microbiol Rev 2017; 41:575-595. [PMID: 28486655 DOI: 10.1093/femsre/fux018] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 04/10/2017] [Indexed: 01/13/2023] Open
Abstract
Coral reefs are one of the most productive ecosystems on the planet, with primary production rates compared to that of rain forests. Benthic organisms release 10-50% of their gross organic production as mucus that stimulates heterotrophic microbial metabolism in the water column. As a result, coral reef microbes grow up to 50 times faster than open ocean communities. Anthropogenic disturbances cause once coral-dominated reefs to become dominated by fleshy organisms, with several outcomes for trophic relationships. Here we review microbial processes implicated in organic carbon flux in coral reefs displaying species phase shifts. The first section presents microbial players and interactions within the coral holobiont that contribute to reef carbon flow. In the second section, we identify four ecosystem-level microbial features that directly respond to benthic species phase shifts: community composition, biomass, metabolism and viral predation. The third section discusses the significance of microbial consumption of benthic organic matter to reef trophic relationships. In the fourth section, we propose that the 'microbial phase shifts' discussed here are conducive to lower resilience, facilitating the transition to new degradation states in coral reefs.
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Affiliation(s)
- Cynthia B Silveira
- Institute of Biology and COPPE/SAGE, Federal University of Rio de Janeiro. Av. Carlos Chagas Filho, 373, Cidade Universitária, RJ 21941-599, Brazil.,Biology Department, San Diego State University, 5500 Campanille Dr, San Diego, CA 92182, USA
| | - Giselle S Cavalcanti
- Institute of Biology and COPPE/SAGE, Federal University of Rio de Janeiro. Av. Carlos Chagas Filho, 373, Cidade Universitária, RJ 21941-599, Brazil.,Biology Department, San Diego State University, 5500 Campanille Dr, San Diego, CA 92182, USA
| | - Juline M Walter
- Institute of Biology and COPPE/SAGE, Federal University of Rio de Janeiro. Av. Carlos Chagas Filho, 373, Cidade Universitária, RJ 21941-599, Brazil
| | - Arthur W Silva-Lima
- Institute of Biology and COPPE/SAGE, Federal University of Rio de Janeiro. Av. Carlos Chagas Filho, 373, Cidade Universitária, RJ 21941-599, Brazil
| | - Elizabeth A Dinsdale
- Biology Department, San Diego State University, 5500 Campanille Dr, San Diego, CA 92182, USA
| | - David G Bourne
- College of Science and Engineering, James Cook University and Australian Institute of Marine Science, Townsville, Queensland 4810, Australia
| | - Cristiane C Thompson
- Institute of Biology and COPPE/SAGE, Federal University of Rio de Janeiro. Av. Carlos Chagas Filho, 373, Cidade Universitária, RJ 21941-599, Brazil
| | - Fabiano L Thompson
- Institute of Biology and COPPE/SAGE, Federal University of Rio de Janeiro. Av. Carlos Chagas Filho, 373, Cidade Universitária, RJ 21941-599, Brazil
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Machado H, Gram L. Comparative Genomics Reveals High Genomic Diversity in the Genus Photobacterium. Front Microbiol 2017; 8:1204. [PMID: 28706512 PMCID: PMC5489566 DOI: 10.3389/fmicb.2017.01204] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/13/2017] [Indexed: 11/13/2022] Open
Abstract
Vibrionaceae is a large marine bacterial family, which can constitute up to 50% of the prokaryotic population in marine waters. Photobacterium is the second largest genus in the family and we used comparative genomics on 35 strains representing 16 of the 28 species described so far, to understand the genomic diversity present in the Photobacterium genus. Such understanding is important for ecophysiology studies of the genus. We used whole genome sequences to evaluate phylogenetic relationships using several analyses (16S rRNA, MLSA, fur, amino-acid usage, ANI), which allowed us to identify two misidentified strains. Genome analyses also revealed occurrence of higher and lower GC content clades, correlating with phylogenetic clusters. Pan- and core-genome analysis revealed the conservation of 25% of the genome throughout the genus, with a large and open pan-genome. The major source of genomic diversity could be traced to the smaller chromosome and plasmids. Several of the physiological traits studied in the genus did not correlate with phylogenetic data. Since horizontal gene transfer (HGT) is often suggested as a source of genetic diversity and a potential driver of genomic evolution in bacterial species, we looked into evidence of such in Photobacterium genomes. Genomic islands were the source of genomic differences between strains of the same species. Also, we found transposase genes and CRISPR arrays that suggest multiple encounters with foreign DNA. Presence of genomic exchange traits was widespread and abundant in the genus, suggesting a role in genomic evolution. The high genetic variability and indications of genetic exchange make it difficult to elucidate genome evolutionary paths and raise the awareness of the roles of foreign DNA in the genomic evolution of environmental organisms.
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Affiliation(s)
- Henrique Machado
- Department of Biotechnology and Biomedicine, Technical University of Denmark, MatematiktorvetKgs Lyngby, Denmark.,Novo Nordisk Foundation Center for Biosustainability, Technical University of DenmarkHørsholm, Denmark
| | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, MatematiktorvetKgs Lyngby, Denmark
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Satinsky BM, Smith CB, Sharma S, Landa M, Medeiros PM, Coles VJ, Yager PL, Crump BC, Moran MA. Expression patterns of elemental cycling genes in the Amazon River Plume. ISME JOURNAL 2017; 11:1852-1864. [PMID: 28387773 DOI: 10.1038/ismej.2017.46] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 02/16/2017] [Indexed: 11/10/2022]
Abstract
Metatranscriptomics and metagenomics data sets benchmarked with internal standards were used to characterize the expression patterns for biogeochemically relevant bacterial and archaeal genes mediating carbon, nitrogen, phosphorus and sulfur uptake and metabolism through the salinity gradient of the Amazon River Plume. The genes were identified in 48 metatranscriptomic and metagenomic data sets summing to >500 million quality-controlled reads from six locations in the plume ecosystem. The ratio of transcripts per gene copy (a direct measure of expression made possible by internal standard additions) showed that the free-living bacteria and archaea exhibited only small changes in the expression levels of biogeochemically relevant genes through the salinity and nutrient zones of the plume. In contrast, the expression levels of genes in particle-associated cells varied over orders of magnitude among the stations, with the largest differences measured for genes mediating aspects of nitrogen cycling (nifH, amtB and amoA) and phosphorus acquisition (pstC, phoX and phoU). Taxa varied in their baseline gene expression levels and extent of regulation, and most of the spatial variation in the expression level could be attributed to changes in gene regulation after removing the effect of shifting taxonomic composition. We hypothesize that changes in microbial element cycling along the Amazon River Plume are largely driven by shifting activities of particle-associated cells, with most activities peaking in the mesohaline regions where N2 fixation rates are elevated.
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Affiliation(s)
| | - Christa B Smith
- Department of Marine Sciences, University of Georgia, Athens, GA, USA
| | - Shalabh Sharma
- Department of Marine Sciences, University of Georgia, Athens, GA, USA
| | - Marine Landa
- Department of Marine Sciences, University of Georgia, Athens, GA, USA
| | | | - Victoria J Coles
- Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA
| | - Patricia L Yager
- Department of Marine Sciences, University of Georgia, Athens, GA, USA
| | - Byron C Crump
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - Mary Ann Moran
- Department of Marine Sciences, University of Georgia, Athens, GA, USA
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Sun Y, Powell KE, Sung W, Lynch M, Moran MA, Luo H. Spontaneous mutations of a model heterotrophic marine bacterium. ISME JOURNAL 2017; 11:1713-1718. [PMID: 28323279 DOI: 10.1038/ismej.2017.20] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 11/06/2016] [Accepted: 12/23/2016] [Indexed: 11/09/2022]
Abstract
Heterotrophic marine bacterioplankton populations display substantive genomic diversity that is commonly explained to be the result of selective forces imposed by resource limitation or interactions with phage and predators. Here we use a mutation-accumulation experiment followed by whole-genome sequencing of mutation lines to determine an unbiased rate and molecular spectrum of spontaneous mutations for a model heterotrophic marine bacterium in the globally important Roseobacter clade, Ruegeria pomeroyi DSS-3. We find evidence for mutational bias towards deletions over insertions, and this process alone could account for a sizable portion of genome size diversity among roseobacters and also implies that lateral gene transfer and/or selection must also play a role in maintaining roseobacters with large genome sizes. We also find evidence for a mutational bias in favor of changes from A/T to G/C nucleobases, which explains widespread occurrences of G/C-enriched Roseobacter genomes. Using the calculated mutation rate of 1.39 × 10-10 per base per generation, we implement a 'mutation-rate clock' approach to date the evolution of roseobacters by assuming a constant mutation rate along their evolutionary history. This approach gives an estimated date of Roseobacter genome expansion in good agreement with an earlier fossil-based estimate of ~250 million years ago and is consistent with a hypothesis of a correlated evolutionary history between roseobacters and marine eukaryotic phytoplankton groups.
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Affiliation(s)
- Ying Sun
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and Partner State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Kate E Powell
- Department of Marine Sciences, University of Georgia, Athens, GA, USA
| | - Way Sung
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Michael Lynch
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Mary Ann Moran
- Department of Marine Sciences, University of Georgia, Athens, GA, USA
| | - Haiwei Luo
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and Partner State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China.,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
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Liu F, Li J, Feng G, Li Z. New Genomic Insights into "Entotheonella" Symbionts in Theonella swinhoei: Mixotrophy, Anaerobic Adaptation, Resilience, and Interaction. Front Microbiol 2016; 7:1333. [PMID: 27610106 PMCID: PMC4996862 DOI: 10.3389/fmicb.2016.01333] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 08/12/2016] [Indexed: 12/11/2022] Open
Abstract
“Entotheonella” (phylum “Tectomicrobia”) is a filamentous symbiont that produces almost all known bioactive compounds derived from the Lithistida sponge Theonella swinhoei. In contrast to the comprehensive knowledge of its secondary metabolism, knowledge of its lifestyle, resilience, and interaction with the sponge host and other symbionts remains rudimentary. In this study, we obtained two “Entotheonella” genomes from T. swinhoei from the South China Sea through metagenome binning, and used a RASTtk pipeline to achieve better genome annotation. The high average nucleotide index values suggested they were the same phylotypes as the two “Entotheonella” phylotypes from T. swinhoei from the Japan Sea. Genomic features related to utilization of various carbon sources, peptidase secretion, CO2 fixation, sulfate reduction, anaerobic respiration, and denitrification indicated the mixotrophic nature of “Entotheonella.” The endospore-forming potential along with metal- and antibiotic resistance indicated “Entotheonella” was highly resilient to harsh conditions. The potential for endospore formation also explained the widespread distribution of “Entotheonella” to some extent. The discovery of Type II (general secretion pathway proteins and the Widespread Colonization Island) and Type VI secretion systems in “Entotheonella” suggested it could secrete extracellular hydrolases, form tight adhesion, act against phagocytes, and kill other prokaryotes. Overall, the newly discovered genomic features suggest “Entotheonella” is a highly competitive member of the symbiotic community of T. swinhoei.
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Affiliation(s)
- Fang Liu
- Marine Biotechnology Laboratory, Department of Bioengineering, State Key Laboratory of Microbial Metabolism-School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China
| | - Jinlong Li
- Marine Biotechnology Laboratory, Department of Bioengineering, State Key Laboratory of Microbial Metabolism-School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China
| | - Guofang Feng
- Marine Biotechnology Laboratory, Department of Bioengineering, State Key Laboratory of Microbial Metabolism-School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China
| | - Zhiyong Li
- Marine Biotechnology Laboratory, Department of Bioengineering, State Key Laboratory of Microbial Metabolism-School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China
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A novel roseobacter phage possesses features of podoviruses, siphoviruses, prophages and gene transfer agents. Sci Rep 2016; 6:30372. [PMID: 27460944 PMCID: PMC4961962 DOI: 10.1038/srep30372] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/30/2016] [Indexed: 11/09/2022] Open
Abstract
Bacteria in the Roseobacter lineage have been studied extensively due to their significant biogeochemical roles in the marine ecosystem. However, our knowledge on bacteriophage which infects the Roseobacter clade is still very limited. Here, we report a new bacteriophage, phage DSS3Φ8, which infects marine roseobacter Ruegeria pomeroyi DSS-3. DSS3Φ8 is a lytic siphovirus. Genomic analysis showed that DSS3Φ8 is most closely related to a group of siphoviruses, CbK-like phages, which infect freshwater bacterium Caulobacter crescentus. DSS3Φ8 contains a smaller capsid and has a reduced genome size (146 kb) compared to the CbK-like phages (205-279 kb). DSS3Φ8 contains the DNA polymerase gene which is closely related to T7-like podoviruses. DSS3Φ8 also contains the integrase and repressor genes, indicating its potential to involve in lysogenic cycle. In addition, four GTA (gene transfer agent) genes were identified in the DSS3Φ8 genome. Genomic analysis suggests that DSS3Φ8 is a highly mosaic phage that inherits the genetic features from siphoviruses, podoviruses, prophages and GTAs. This is the first report of CbK-like phages infecting marine bacteria. We believe phage isolation is still a powerful tool that can lead to discovery of new phages and help interpret the overwhelming unknown sequences in the viral metagenomics.
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Patzelt D, Michael V, Päuker O, Ebert M, Tielen P, Jahn D, Tomasch J, Petersen J, Wagner-Döbler I. Gene Flow Across Genus Barriers - Conjugation of Dinoroseobacter shibae's 191-kb Killer Plasmid into Phaeobacter inhibens and AHL-mediated Expression of Type IV Secretion Systems. Front Microbiol 2016; 7:742. [PMID: 27303368 PMCID: PMC4886583 DOI: 10.3389/fmicb.2016.00742] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 05/03/2016] [Indexed: 01/24/2023] Open
Abstract
Rhodobacteraceae harbor a conspicuous wealth of extrachromosomal replicons (ECRs) and therefore the exchange of genetic material via horizontal transfer has been supposed to be a major evolutionary driving force. Many plasmids in this group encode type IV secretion systems (T4SS) that are expected to mediate transfer of proteins and/or DNA into host cells, but no experimental evidence of either has yet been provided. Dinoroseobacter shibae, a species of the Roseobacter group within the Rhodobacteraceae family, contains five ECRs that are crucial for anaerobic growth, survival under starvation and the pathogenicity of this model organism. Here we tagged two syntenous but compatible RepABC-type plasmids of 191 and 126-kb size, each encoding a T4SS, with antibiotic resistance genes and demonstrated their conjugational transfer into a distantly related Roseobacter species, namely Phaeobacter inhibens. Pulsed field gel electrophoresis showed transfer of those replicons into the recipient both individually but also together documenting the efficiency of conjugation. We then studied the influence of externally added quorum sensing (QS) signals on the expression of the T4SS located on the sister plasmids. A QS deficient D. shibae null mutant (ΔluxI1) lacking synthesis of N-acyl-homoserine lactones (AHLs) was cultivated with a wide spectrum of chemically diverse long-chain AHLs. All AHLs with lengths of the acid side-chain ≥14 reverted the ΔluxI1 phenotype to wild-type. Expression of the T4SS was induced up to log2 ∼3fold above wild-type level. We hypothesize that conjugation in roseobacters is QS-controlled and that the QS system may detect a wide array of long-chain AHLs at the cell surface.
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Affiliation(s)
- Diana Patzelt
- Department of Microbiology, Microbial Communication, Helmholtz-Centre for Infection Research Braunschweig, Germany
| | - Victoria Michael
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures Braunschweig, Germany
| | - Orsola Päuker
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures Braunschweig, Germany
| | - Matthias Ebert
- Braunschweig University of Technology Braunschweig, Germany
| | - Petra Tielen
- Braunschweig University of Technology Braunschweig, Germany
| | - Dieter Jahn
- Braunschweig University of Technology Braunschweig, Germany
| | - Jürgen Tomasch
- Department of Microbiology, Microbial Communication, Helmholtz-Centre for Infection Research Braunschweig, Germany
| | - Jörn Petersen
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures Braunschweig, Germany
| | - Irene Wagner-Döbler
- Department of Microbiology, Microbial Communication, Helmholtz-Centre for Infection Research Braunschweig, Germany
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Gómez-Lunar Z, Hernández-González I, Rodríguez-Torres MD, Souza V, Olmedo-Álvarez G. Microevolution Analysis of Bacillus coahuilensis Unveils Differences in Phosphorus Acquisition Strategies and Their Regulation. Front Microbiol 2016; 7:58. [PMID: 26903955 PMCID: PMC4744853 DOI: 10.3389/fmicb.2016.00058] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 01/13/2016] [Indexed: 11/27/2022] Open
Abstract
Bacterial genomes undergo numerous events of gene losses and gains that generate genome variability among strains of the same species (microevolution). Our aim was to compare the genomes and relevant phenotypes of three Bacillus coahuilensis strains from two oligotrophic hydrological systems in the Cuatro Ciénegas Basin (México), to unveil the environmental challenges that this species cope with, and the microevolutionary differences in these genotypes. Since the strains were isolated from a low P environment, we placed emphasis on the search of different phosphorus acquisition strategies. The three B. coahuilensis strains exhibited similar numbers of coding DNA sequences, of which 82% (2,893) constituted the core genome, and 18% corresponded to accessory genes. Most of the genes in this last group were associated with mobile genetic elements (MGEs) or were annotated as hypothetical proteins. Ten percent of the pangenome consisted of strain-specific genes. Alignment of the three B. coahuilensis genomes indicated a high level of synteny and revealed the presence of several genomic islands. Unexpectedly, one of these islands contained genes that encode the 2-keto-3-deoxymannooctulosonic acid (Kdo) biosynthesis enzymes, a feature associated to cell walls of Gram-negative bacteria. Some microevolutionary changes were clearly associated with MGEs. Our analysis revealed inconsistencies between phenotype and genotype, which we suggest result from the impossibility to map regulatory features to genome analysis. Experimental results revealed variability in the types and numbers of auxotrophies between the strains that could not consistently be explained by in silico metabolic models. Several intraspecific differences in preferences for carbohydrate and phosphorus utilization were observed. Regarding phosphorus recycling, scavenging, and storage, variations were found between the three genomes. The three strains exhibited differences regarding alkaline phosphatase that revealed that in addition to gene gain and loss, regulation adjustment of gene expression also has contributed to the intraspecific diversity of B. coahuilensis.
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Affiliation(s)
- Zulema Gómez-Lunar
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, Mexico
| | - Ismael Hernández-González
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, Mexico
| | - María-Dolores Rodríguez-Torres
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, Mexico
| | - Valeria Souza
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México México City, Mexico
| | - Gabriela Olmedo-Álvarez
- Laboratorio de Biología Molecular y Ecología Microbiana, Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Irapuato, Mexico
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Ecological Genomics of the Uncultivated Marine Roseobacter Lineage CHAB-I-5. Appl Environ Microbiol 2016; 82:2100-2111. [PMID: 26826224 DOI: 10.1128/aem.03678-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/20/2016] [Indexed: 01/28/2023] Open
Abstract
Members of the marine Roseobacter clade are major participants in global carbon and sulfur cycles. While roseobacters are well represented in cultures, several abundant pelagic lineages, including SAG-O19, DC5-80-3, and NAC11-7, remain largely uncultivated and show evidence of genome streamlining. Here, we analyzed the partial genomes of three single cells affiliated with CHAB-I-5, another abundant but exclusively uncultivated Roseobacter lineage. Members of this lineage encode several metabolic potentials that are absent in streamlined genomes. Examples are quorum sensing and type VI secretion systems, which enable them to effectively interact with host and other bacteria. Further analysis of the CHAB-I-5 single-cell amplified genomes (SAGs) predicted that this lineage comprises members with relatively large genomes (4.1 to 4.4 Mbp) and a high fraction of noncoding DNA (10 to 12%), which is similar to what is observed in many cultured, nonstreamlined Roseobacter lineages. The four uncultured lineages, while exhibiting highly variable geographic distributions, together represent >60% of the global pelagic roseobacters. They are consistently enriched in genes encoding the capabilities of light harvesting, oxidation of "energy-rich" reduced sulfur compounds and methylated amines, uptake and catabolism of various carbohydrates and osmolytes, and consumption of abundant exudates from phytoplankton. These traits may define the global prevalence of the four lineages among marine bacterioplankton.
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Trace Metal Acquisition by Marine Heterotrophic Bacterioplankton with Contrasting Trophic Strategies. Appl Environ Microbiol 2016; 82:1613-1624. [PMID: 26729720 PMCID: PMC4771312 DOI: 10.1128/aem.03128-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 12/17/2015] [Indexed: 12/14/2022] Open
Abstract
Heterotrophic bacteria in the SAR11 and Roseobacter lineages shape the marine carbon, nitrogen, phosphorous, and sulfur cycles, yet they do so having adopted divergent ecological strategies. Currently, it is unknown whether these globally significant groups partition into specific niches with respect to micronutrients (e.g., trace metals) and how that may affect marine trace metal cycling. Here, we used comparative genomics to identify diverse iron, cobalt, nickel, copper, and zinc uptake capabilities in SAR11 and Roseobacter genomes and uncover surprising unevenness within and between lineages. The strongest predictors for the extent of the metal uptake gene content are the total number of transporters per genome, genome size, total metal transporters, and GC content, but numerous exceptions exist in both groups. Taken together, our results suggest that SAR11 have strongly minimized their trace metal uptake versatility, with high-affinity zinc uptake being a unique exception. The larger Roseobacter genomes have greater trace metal uptake versatility on average, but they also appear to have greater plasticity, resulting in phylogenetically similar genomes having largely different capabilities. Ultimately, phylogeny is predictive of the diversity and extent of 20 to 33% of all metal uptake systems, suggesting that specialization in metal utilization mostly occurred independently from overall lineage diversification in both SAR11 and Roseobacter. We interpret these results as reflecting relatively recent trace metal niche partitioning in both lineages, suggesting that concentrations and chemical forms of metals in the marine environment are important factors shaping the gene content of marine heterotrophic Alphaproteobacteria of the SAR11 and Roseobacter lineages.
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