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Zhang L, Lin W, Sardans J, Li X, Hui D, Yang Z, Wang H, Lin H, Wang Y, Guo J, Peñuelas J, Yang Y. Soil warming-induced reduction in water content enhanced methane uptake at different soil depths in a subtropical forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:171994. [PMID: 38561130 DOI: 10.1016/j.scitotenv.2024.171994] [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: 12/12/2023] [Revised: 02/05/2024] [Accepted: 03/24/2024] [Indexed: 04/04/2024]
Abstract
Global warming can significantly impact soil CH4 uptake in subtropical forests due to changes in soil moisture, temperature sensitivity of methane-oxidizing bacteria (MOB), and shifts in microbial communities. However, the specific effects of climate warming and the underlying mechanisms on soil CH4 uptake at different soil depths remain poorly understood. To address this knowledge gap, we conducted a soil warming experiment (+4 °C) in a natural forest. From August 2020 to October 2021, we measured soil temperature, soil moisture, and CH4 uptake rates at four different soil depths: 0-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm. Additionally, we assessed the soil MOB community structure and pmoA gene (with qPCR) at the 0-10 and 10-20 cm depths. Our findings revealed that warming significantly enhanced soil net CH4 uptake rate by 12.28 %, 29.51 %, and 61.05 % in the 0-10, 20-40, and 40-60 cm soil layers, respectively. The warming also led to reduced soil moisture levels, with more pronounced reductions observed at the 20-40 cm depth compared to the 0-20 cm depth. At the 0-10 cm depth, warming increased the relative abundance of upland soil cluster α (a type of MOB) and decreased the relative abundance of Methylocystis, but it did not significantly increase the pmoA gene copies. Our structural equation model analysis indicated that warming directly regulated soil CH4 uptake rate through the decrease in soil moisture, rather than through changes in the pmoA gene and MOB community structure at the 0-20 cm depth. In summary, our results demonstrate that warming enhances soil CH4 uptake at different depths, with soil moisture playing a crucial role in this process. Under warming conditions, the drier soil pores allow for better CH4 penetration, thereby promoting more efficient activity of MOB.
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Affiliation(s)
- Lei Zhang
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou 350117, China
| | - Weisheng Lin
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou 350117, China; Institute of Geography, Fujian Normal University, Fuzhou 350117, China; Fujian Sanming Forest Ecosystem National Observation and Research Station, Fujian normal University, Sanming 365002, China.
| | - Jordi Sardans
- CSIC, Global Ecology Unit, CREAF-CSIC-UAB, Bellaterra, Barcelona 08193, Catalonia, Spain; CREAF, Cerdanyola del Vallès, Barcelona 08193, Catalonia, Spain
| | - Xiaoling Li
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou 350117, China
| | - Dafeng Hui
- Department of Biological Sciences, Tennessee State University, Nashville, TN 37209, USA
| | - Zhijie Yang
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou 350117, China; Institute of Geography, Fujian Normal University, Fuzhou 350117, China; Fujian Sanming Forest Ecosystem National Observation and Research Station, Fujian normal University, Sanming 365002, China
| | - Haizhen Wang
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou 350117, China
| | - Hao Lin
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou 350117, China
| | - Yufang Wang
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, Gansu Province, China
| | - Jianfen Guo
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou 350117, China; Institute of Geography, Fujian Normal University, Fuzhou 350117, China; Fujian Sanming Forest Ecosystem National Observation and Research Station, Fujian normal University, Sanming 365002, China.
| | - Josep Peñuelas
- CSIC, Global Ecology Unit, CREAF-CSIC-UAB, Bellaterra, Barcelona 08193, Catalonia, Spain; CREAF, Cerdanyola del Vallès, Barcelona 08193, Catalonia, Spain
| | - Yusheng Yang
- Institute of Geography, Fujian Normal University, Fuzhou 350117, China; Fujian Sanming Forest Ecosystem National Observation and Research Station, Fujian normal University, Sanming 365002, China
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2
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Danilova OV, Oshkin IY, Belova SE, Miroshnikov KK, Ivanova AA, Dedysh SN. One Step Closer to Enigmatic USCα Methanotrophs: Isolation of a Methylocapsa-like Bacterium from a Subarctic Soil. Microorganisms 2023; 11:2800. [PMID: 38004811 PMCID: PMC10672854 DOI: 10.3390/microorganisms11112800] [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: 10/13/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
The scavenging of atmospheric trace gases has been recognized as one of the lifestyle-defining capabilities of microorganisms in terrestrial polar ecosystems. Several metagenome-assembled genomes of as-yet-uncultivated methanotrophic bacteria, which consume atmospheric CH4 in these ecosystems, have been retrieved in cultivation-independent studies. In this study, we isolated and characterized a representative of these methanotrophs, strain D3K7, from a subarctic soil of northern Russia. Strain D3K7 grows on methane and methanol in a wide range of temperatures, between 5 and 30 °C. Weak growth was also observed on acetate. The presence of acetate in the culture medium stimulated growth at low CH4 concentrations (~100 p.p.m.v.). The finished genome sequence of strain D3K7 is 4.15 Mb in size and contains about 3700 protein-encoding genes. According to the result of phylogenomic analysis, this bacterium forms a common clade with metagenome-assembled genomes obtained from the active layer of a permafrost thaw gradient in Stordalen Mire, Abisco, Sweden, and the mineral cryosol at Axel Heiberg Island in the Canadian High Arctic. This clade occupies a phylogenetic position in between characterized Methylocapsa methanotrophs and representatives of the as-yet-uncultivated upland soil cluster alpha (USCα). As shown by the global distribution analysis, D3K7-like methanotrophs are not restricted to polar habitats but inhabit peatlands and soils of various climatic zones.
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Affiliation(s)
| | | | | | | | | | - Svetlana N. Dedysh
- Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences Leninsky Ave. 33/2, Moscow 119071, Russia; (O.V.D.); (I.Y.O.); (S.E.B.); (A.A.I.)
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3
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Ho A, Zuan ATK, Mendes LW, Lee HJ, Zulkeflee Z, van Dijk H, Kim PJ, Horn MA. Aerobic Methanotrophy and Co-occurrence Networks of a Tropical Rainforest and Oil Palm Plantations in Malaysia. MICROBIAL ECOLOGY 2022; 84:1154-1165. [PMID: 34716776 PMCID: PMC9747831 DOI: 10.1007/s00248-021-01908-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/21/2021] [Indexed: 05/11/2023]
Abstract
Oil palm (OP) plantations are gradually replacing tropical rainforest in Malaysia, one of the largest palm oil producers globally. Conversion of lands to OP plantations has been associated with compositional shifts of the microbial community, with consequences on the greenhouse gas (GHG) emissions. While the impact of the change in land use has recently been investigated for microorganisms involved in N2O emission, the response of the aerobic methanotrophs to OP agriculture remains to be determined. Here, we monitored the bacterial community composition, focusing on the aerobic methanotrophs, in OP agricultural soils since 2012, 2006, and 1993, as well as in a tropical rainforest, in 2019 and 2020. High-affinity methane uptake was confirmed, showing significantly lower rates in the OP plantations than in the tropical rainforest, but values increased with continuous OP agriculture. The bacterial, including the methanotrophic community composition, was modified with ongoing OP agriculture. The methanotrophic community composition was predominantly composed of unclassified methanotrophs, with the canonical (Methylocystis) and putative methanotrophs thought to catalyze high-affinity methane oxidation present at higher relative abundance in the oldest OP plantation. Results suggest that the methanotrophic community was relatively more stable within each site, exhibiting less temporal variations than the total bacterial community. Uncharacteristically, a 16S rRNA gene-based co-occurrence network analysis revealed a more complex and connected community in the OP agricultural soil, which may influence the resilience of the bacterial community to disturbances. Overall, we provide a first insight into the ecology and role of the aerobic methanotrophs as a methane sink in OP agricultural soils.
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Affiliation(s)
- Adrian Ho
- Institute for Microbiology, Leibniz Universität Hannover, Hannover, Germany.
| | - Ali Tan Kee Zuan
- Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, Seri Kembangan, Selangor, Malaysia
| | - Lucas W Mendes
- Center for Nuclear Energy in Agriculture, University of São Paulo (CENA-USP), Sao Paulo, Brazil
| | - Hyo Jung Lee
- Department of Biology, Kunsan National University, Gunsan, South Korea
| | - Zufarzaana Zulkeflee
- Department of Environment, Faculty of Forestry and Environment, Universiti Putra Malaysia, Seri Kembangan, Selangor, Malaysia
| | - Hester van Dijk
- Institute for Microbiology, Leibniz Universität Hannover, Hannover, Germany
| | - Pil Joo Kim
- Division of Applied Life Science, Gyeongsang National University, Jinju, South Korea
| | - Marcus A Horn
- Institute for Microbiology, Leibniz Universität Hannover, Hannover, Germany
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4
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Greening C, Grinter R. Microbial oxidation of atmospheric trace gases. Nat Rev Microbiol 2022; 20:513-528. [PMID: 35414013 DOI: 10.1038/s41579-022-00724-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2022] [Indexed: 02/06/2023]
Abstract
The atmosphere has recently been recognized as a major source of energy sustaining life. Diverse aerobic bacteria oxidize the three most abundant reduced trace gases in the atmosphere, namely hydrogen (H2), carbon monoxide (CO) and methane (CH4). This Review describes the taxonomic distribution, physiological role and biochemical basis of microbial oxidation of these atmospheric trace gases, as well as the ecological, environmental, medical and astrobiological importance of this process. Most soil bacteria and some archaea can survive by using atmospheric H2 and CO as alternative energy sources, as illustrated through genetic studies on Mycobacterium cells and Streptomyces spores. Certain specialist bacteria can also grow on air alone, as confirmed by the landmark characterization of Methylocapsa gorgona, which grows by simultaneously consuming atmospheric CH4, H2 and CO. Bacteria use high-affinity lineages of metalloenzymes, namely hydrogenases, CO dehydrogenases and methane monooxygenases, to utilize atmospheric trace gases for aerobic respiration and carbon fixation. More broadly, trace gas oxidizers enhance the biodiversity and resilience of soil and marine ecosystems, drive primary productivity in extreme environments such as Antarctic desert soils and perform critical regulatory services by mitigating anthropogenic emissions of greenhouse gases and toxic pollutants.
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Affiliation(s)
- Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia. .,Securing Antarctica's Environmental Future, Monash University, Clayton, Victoria, Australia. .,Centre to Impact AMR, Monash University, Clayton, Victoria, Australia.
| | - Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
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5
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Atmospheric Methane Consumption and Methanotroph Communities in West Siberian Boreal Upland Forest Ecosystems. FORESTS 2021. [DOI: 10.3390/f12121738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Upland forest ecosystems are recognized as net sinks for atmospheric methane (CH4), one of the most impactful greenhouse gases. Biological methane uptake in these ecosystems occurs due to the activity of aerobic methanotrophic bacteria. Russia hosts one-fifth of the global forest area, with the most extensive forest landscapes located in West Siberia. Here, we report seasonal CH4 flux measurements conducted in 2018 in three types of stands in West Siberian middle taiga–Siberian pine, Aspen, and mixed forests. High rates of methane uptake of up to −0.184 mg CH4 m−2 h−1 were measured by a static chamber method, with an estimated total growing season consumption of 4.5 ± 0.5 kg CH4 ha−1. Forest type had little to no effect on methane fluxes within each season. Soil methane oxidation rate ranged from 0 to 8.1 ng CH4 gDW−1 h−1 and was negatively related to water-filled pore space. The microbial soil communities were dominated by the Alpha- and Gammaproteobacteria, Acidobacteriota and Actinobacteriota. The major group of 16S rRNA gene reads from methanotrophs belonged to uncultivated Beijerinckiaceae bacteria. Molecular identification of methanotrophs based on retrieval of the pmoA gene confirmed that Upland Soil Cluster Alpha was the major bacterial group responsible for CH4 oxidation.
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6
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Praeg N, Schachner I, Schuster L, Illmer P. Carbon-dependent growth, community structure and methane oxidation performance of a soil-derived methanotrophic mixed culture. FEMS Microbiol Lett 2021; 368:6035239. [PMID: 33320954 DOI: 10.1093/femsle/fnaa212] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/11/2020] [Indexed: 11/13/2022] Open
Abstract
Soil-borne methane-oxidizing microorganisms act as a terrestrial methane (CH4) sink and are potentially useful in decreasing global CH4 emissions. Understanding the ecophysiology of methanotrophs is crucial for a thorough description of global carbon cycling. Here, we report the in situ balance of soils from abandoned landfills, meadows and wetlands, their capacities to produce and oxidize CH4 at laboratory-scale and the isolation of a soil-borne methanotrophic-heterotrophic mixed culture that was used for carbon (C1 and C2) feeding experiments. We showed that even with similar soil properties, the in situ CH4 balance depends on land-use. Different soils had different potentials to adapt to increased CH4 availability, leading to the highest CH4 oxidation capacities for landfill and wetland soils. The most efficient mixed culture isolated from the landfill was dominated by the methanotrophs Methylobacter sp. and Methylosinus sp., which were accompanied by Variovorax sp. and Pseudomonas sp. and remained active in oxidizing CH4 when supplied with additional C-sources. The ratios between type I and type II methanotrophs and between methanotrophic and heterotrophic bacteria changed when C-sources were altered. A significant effect of the application of the mixed culture on the CH4 oxidation of soils was established but the extent varied depending on soil type.
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Affiliation(s)
- Nadine Praeg
- Universität Innsbruck, Department of Microbiology, Technikerstrasse 25d, A-6020 Innsbruck, Austria
| | - Iris Schachner
- Universität Innsbruck, Department of Microbiology, Technikerstrasse 25d, A-6020 Innsbruck, Austria
| | - Lisa Schuster
- Universität Innsbruck, Department of Microbiology, Technikerstrasse 25d, A-6020 Innsbruck, Austria
| | - Paul Illmer
- Universität Innsbruck, Department of Microbiology, Technikerstrasse 25d, A-6020 Innsbruck, Austria
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7
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Disproportionate CH 4 Sink Strength from an Endemic, Sub-Alpine Australian Soil Microbial Community. Microorganisms 2021; 9:microorganisms9030606. [PMID: 33804229 PMCID: PMC8002156 DOI: 10.3390/microorganisms9030606] [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: 01/31/2021] [Revised: 02/27/2021] [Accepted: 03/09/2021] [Indexed: 11/17/2022] Open
Abstract
Soil-to-atmosphere methane (CH4) fluxes are dependent on opposing microbial processes of production and consumption. Here we use a soil–vegetation gradient in an Australian sub-alpine ecosystem to examine links between composition of soil microbial communities, and the fluxes of greenhouse gases they regulate. For each soil/vegetation type (forest, grassland, and bog), we measured carbon dioxide (CO2) and CH4 fluxes and their production/consumption at 5 cm intervals to a depth of 30 cm. All soils were sources of CO2, ranging from 49 to 93 mg CO2 m−2 h−1. Forest soils were strong net sinks for CH4, at rates of up to −413 µg CH4 m−2 h−1. Grassland soils varied, with some soils acting as sources and some as sinks, but overall averaged −97 µg CH4 m−2 h−1. Bog soils were net sources of CH4 (+340 µg CH4 m−2 h−1). Methanotrophs were dominated by USCα in forest and grassland soils, and Candidatus Methylomirabilis in the bog soils. Methylocystis were also detected at relatively low abundance in all soils. Our study suggests that there is a disproportionately large contribution of these ecosystems to the global soil CH4 sink, which highlights our dependence on soil ecosystem services in remote locations driven by unique populations of soil microbes. It is paramount to explore and understand these remote, hard-to-reach ecosystems to better understand biogeochemical cycles that underpin global sustainability.
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8
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Microbial Communities in Methane Cycle: Modern Molecular Methods Gain Insights into Their Global Ecology. ENVIRONMENTS 2021. [DOI: 10.3390/environments8020016] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The role of methane as a greenhouse gas in the concept of global climate changes is well known. Methanogens and methanotrophs are two microbial groups which contribute to the biogeochemical methane cycle in soil, so that the total emission of CH4 is the balance between its production and oxidation by microbial communities. Traditional identification techniques, such as selective enrichment and pure-culture isolation, have been used for a long time to study diversity of methanogens and methanotrophs. However, these techniques are characterized by significant limitations, since only a relatively small fraction of the microbial community could be cultured. Modern molecular methods for quantitative analysis of the microbial community such as real-time PCR (Polymerase chain reaction), DNA fingerprints and methods based on high-throughput sequencing together with different “omics” techniques overcome the limitations imposed by culture-dependent approaches and provide new insights into the diversity and ecology of microbial communities in the methane cycle. Here, we review available knowledge concerning the abundances, composition, and activity of methanogenic and methanotrophic communities in a wide range of natural and anthropogenic environments. We suggest that incorporation of microbial data could fill the existing microbiological gaps in methane flux modeling, and significantly increase the predictive power of models for different environments.
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9
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Extraction of Microbial Cells from Environmental Samples for FISH Approaches. Methods Mol Biol 2021. [PMID: 33576997 DOI: 10.1007/978-1-0716-1115-9_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Fluorescent in situ hybridization (FISH) on environmental samples has become a standard technique to identify and enumerate microbial populations. However, visualization and quantification of cells in environmental samples with complex matrices is often challenging to impossible, and downstream protocols might also require the absence of organic and inorganic particles for analysis. Therefore, quite often microbial cells have to be detached and extracted from the sample matrix prior to use in FISH. Here, details are given for a routine protocol to extract intact microbial cells from environmental samples using density gradient centrifugation. This protocol is suitable and adaptable for a wide range of environmental samples.
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10
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Belova SE, Danilova OV, Ivanova AA, Merkel AY, Dedysh SN. Methane-Oxidizing Communities in Lichen-Dominated Forested Tundra Are Composed Exclusively of High-Affinity USCα Methanotrophs. Microorganisms 2020; 8:microorganisms8122047. [PMID: 33371270 PMCID: PMC7766663 DOI: 10.3390/microorganisms8122047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 01/04/2023] Open
Abstract
Upland soils of tundra function as a constant sink for atmospheric CH4 but the identity of methane oxidizers in these soils remains poorly understood. Methane uptake rates of -0.4 to -0.6 mg CH4-C m-2 day-1 were determined by the static chamber method in a mildly acidic upland soil of the lichen-dominated forested tundra, North Siberia, Russia. The maximal CH4 oxidation activity was localized in an organic surface soil layer underlying the lichen cover. Molecular identification of methanotrophic bacteria based on retrieval of the pmoA gene revealed Upland Soil Cluster Alpha (USCα) as the only detectable methanotroph group. Quantification of these pmoA gene fragments by means of specific qPCR assay detected ~107pmoA gene copies g-1 dry soil. The pmoA diversity was represented by seven closely related phylotypes; the most abundant phylotype displayed 97.5% identity to pmoA of Candidatus Methyloaffinis lahnbergensis. Further analysis of prokaryote diversity in this soil did not reveal 16S rRNA gene fragments from well-studied methanotrophs of the order Methylococcales and the family Methylocystaceae. The largest group of reads (~4% of all bacterial 16S rRNA gene fragments) that could potentially belong to methanotrophs was classified as uncultivated Beijerinckiaceae bacteria. These reads displayed 96-100 and 95-98% sequence similarity to 16S rRNA gene of Candidatus Methyloaffinis lahnbergensis and "Methylocapsa gorgona" MG08, respectively, and were represented by eight species-level operational taxonomic units (OTUs), two of which were highly abundant. These identification results characterize subarctic upland soils, which are exposed to atmospheric methane concentrations only, as a unique habitat colonized mostly by USCα methanotrophs.
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11
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Praeg N, Illmer P. Microbial community composition in the rhizosphere of Larix decidua under different light regimes with additional focus on methane cycling microorganisms. Sci Rep 2020; 10:22324. [PMID: 33339837 PMCID: PMC7749151 DOI: 10.1038/s41598-020-79143-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 12/01/2020] [Indexed: 02/05/2023] Open
Abstract
Microbial community and diversity in the rhizosphere is strongly influenced by biotic and/or abiotic factors, like root exudates, nutrient availability, edaphon and climate. Here we report on the microbial diversity within the rhizosphere of Larix decidua, a dominant tree species in the Alps, as compared with the microbiome within the surrounding soil. We describe how increased light intensity influenced the rhizobiome and put emphasize on methane cycling microorganisms. Microbial taxa were classified into 26 bacterial, 4 archaeal and 6 fungal phyla revealing significant differences between bulk and rhizosphere soils. The dominant prokaryotic phyla were Proteobacteria, Acidobacteria, Actinobacteria (both, rhizosphere and bulk soil) and Bacteroidetes (rhizosphere soil only) and dominant fungal phyla in both fractions included Ascomycota and Basidiomycota. The rhizosphere community was indicated by Suillus sp., plant growth-promoting bacteria and Candidatus Saccharibacteria. Predicted genes in membrane transport and carbohydrate metabolism were significantly more abundant in rhizosphere soils while genes connected with energy metabolisms and cell motility increased in bulk soils. Dominant methanotrophic microorganisms were Upland Soil Cluster (USC) α methanotrophs, Methylogaea spp. and Methylosinus spp., while most methanogens belonged to Methanomassiliicoccales. The overall abundance of methanotrophs distinctly increased in the rhizosphere but to a very different species-specific extent. The increased light intensity only led to minor changes in the rhizobiome, nevertheless a couple of indicator species (e.g. Pseudomonas sp.) for intensified light conditions were established.
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Affiliation(s)
- Nadine Praeg
- Department of Microbiology, Universität Innsbruck, Technikerstrasse 25d, 6020, Innsbruck, Austria.
| | - Paul Illmer
- Department of Microbiology, Universität Innsbruck, Technikerstrasse 25d, 6020, Innsbruck, Austria
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12
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Chiri E, Greening C, Lappan R, Waite DW, Jirapanjawat T, Dong X, Arndt SK, Nauer PA. Termite mounds contain soil-derived methanotroph communities kinetically adapted to elevated methane concentrations. THE ISME JOURNAL 2020; 14:2715-2731. [PMID: 32709975 PMCID: PMC7784690 DOI: 10.1038/s41396-020-0722-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/07/2020] [Accepted: 07/15/2020] [Indexed: 01/29/2023]
Abstract
Termite mounds have recently been confirmed to mitigate approximately half of termite methane (CH4) emissions, but the aerobic CH4 oxidising bacteria (methanotrophs) responsible for this consumption have not been resolved. Here, we describe the abundance, composition and CH4 oxidation kinetics of the methanotroph communities in the mounds of three distinct termite species sampled from Northern Australia. Results from three independent methods employed show that methanotrophs are rare members of microbial communities in termite mounds, with a comparable abundance but distinct composition to those of adjoining soil samples. Across all mounds, the most abundant and prevalent methane monooxygenase sequences were affiliated with upland soil cluster α (USCα), with sequences homologous to Methylocystis and tropical upland soil cluster (TUSC) also detected. The reconstruction of a metagenome-assembled genome of a mound USCα representative highlighted the metabolic capabilities of this group of methanotrophs. The apparent Michaelis-Menten kinetics of CH4 oxidation in mounds were estimated from in situ reaction rates. Methane affinities of the communities were in the low micromolar range, which is one to two orders of magnitude higher than those of upland soils, but significantly lower than those measured in soils with a large CH4 source such as landfill cover soils. The rate constant of CH4 oxidation, as well as the porosity of the mound material, were significantly positively correlated with the abundance of methanotroph communities of termite mounds. We conclude that termite-derived CH4 emissions have selected for distinct methanotroph communities that are kinetically adapted to elevated CH4 concentrations. However, factors other than substrate concentration appear to limit methanotroph abundance and hence these bacteria only partially mitigate termite-derived CH4 emissions. Our results also highlight the predominant role of USCα in an environment with elevated CH4 concentrations and suggest a higher functional diversity within this group than previously recognised.
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Affiliation(s)
- Eleonora Chiri
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
- School of Ecosystem and Forest Sciences, University of Melbourne, Richmond, VIC, 3121, Australia
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia.
| | - Rachael Lappan
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - David W Waite
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Thanavit Jirapanjawat
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Xiyang Dong
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, 519082, China
| | - Stefan K Arndt
- School of Ecosystem and Forest Sciences, University of Melbourne, Richmond, VIC, 3121, Australia.
| | - Philipp A Nauer
- School of Ecosystem and Forest Sciences, University of Melbourne, Richmond, VIC, 3121, Australia
- School of Chemistry, Monash University, Clayton, VIC, 3800, Australia
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13
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Farhan Ul Haque M, Xu HJ, Murrell JC, Crombie A. Facultative methanotrophs - diversity, genetics, molecular ecology and biotechnological potential: a mini-review. MICROBIOLOGY (READING, ENGLAND) 2020; 166:894-908. [PMID: 33085587 PMCID: PMC7660913 DOI: 10.1099/mic.0.000977] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/20/2020] [Indexed: 12/18/2022]
Abstract
Methane-oxidizing bacteria (methanotrophs) play a vital role in reducing atmospheric methane emissions, and hence mitigating their potent global warming effects. A significant proportion of the methane released is thermogenic natural gas, containing associated short-chain alkanes as well as methane. It was one hundred years following the description of methanotrophs that facultative strains were discovered and validly described. These can use some multi-carbon compounds in addition to methane, often small organic acids, such as acetate, or ethanol, although Methylocella strains can also use short-chain alkanes, presumably deriving a competitive advantage from this metabolic versatility. Here, we review the diversity and molecular ecology of facultative methanotrophs. We discuss the genetic potential of the known strains and outline the consequent benefits they may obtain. Finally, we review the biotechnological promise of these fascinating microbes.
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Affiliation(s)
| | - Hui-Juan Xu
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: Joint Institute for Environmental Research & Education, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China
| | - J. Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Andrew Crombie
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
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14
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Pan J, Wang X, Cao A, Zhao G, Zhou C. Screening methane-oxidizing bacteria from municipal solid waste landfills and simulating their effects on methane and ammonia reduction. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:37082-37091. [PMID: 31745784 DOI: 10.1007/s11356-019-06545-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 09/16/2019] [Indexed: 06/10/2023]
Abstract
Municipal solid waste landfills are not only a crucial source of global greenhouse gas emissions; they also produce large amounts of ammonia (NH3), hydrogen sulfide, and other odorous gases that negatively affect the regional environment. Several types of methane-oxidizing bacteria (MOB) were proved to be effective in mitigating methane emission from landfills. Nevertheless, more MOB species and their technical parameters for best mitigating methane still need to be explored. In landfills, methane is simultaneously generated with ammonia, which may impede the CH4 bio-oxidizing process of MOB. However, very limited studies examined the enhancement of methane reduction by introducing ammonia-oxidizing bacteria (AOB) in landfills. In this study, two enriched MOB cultures were gained from a typical municipal solid waste landfill, and then were cultured with three strains of ammonia-oxidizing bacteria (AOB). The MOB enrichment culture used in this work includes Methylocaldum, Methylocystaceae, and Methyloversatilis, with a methane oxidation capacity of 43.6-65.0%, and the AOB includes Candida ethanolica, Bacillus cereus, and Alcaligenes faecalis. The effects on the emission reduction of both NH3 and CH4 were measured using self-made landfill-simulating equipment, as MOB, AOB, and a MOB-AOB mixture were added to the soil cover of the simulation equipment. The concentrations of CH4 and NH3 in the MOB-AOB mixture group decreased sharply, and the CH4 and NH3 concentration was 76.4% and 83.7% of the control group level. We also found that addition of AOB can help MOB oxidize CH4 and improve the emission reduction effect.
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Affiliation(s)
- Jingran Pan
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China
| | - Xiaolin Wang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China
| | - Aixin Cao
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Guozhu Zhao
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China.
| | - Chuanbin Zhou
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
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Methane and Nitrous Oxide Flux after Biochar Application in Subtropical Acidic Paddy Soils under Tobacco-Rice Rotation. Sci Rep 2019; 9:17277. [PMID: 31754121 PMCID: PMC6872536 DOI: 10.1038/s41598-019-53044-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 10/28/2019] [Indexed: 12/23/2022] Open
Abstract
Biochar amendment is a good means of mitigating methane (CH4) and nitrous oxide (N2O) emissions. However, the effects of biochar amendment on N2O and CH4 reduction in soil under rotation with different soil moisture contents is not well understood. To understand CH4 and N2O flux from soil with biochar amendment under water-unsaturated and water-saturated conditions, a field experiment was conducted in a tobacco-rice rotation field in subtropical China to investigate N2O and CH4 emissions following soil amendment with tobacco straw biochar at rates of 0, 10, 40 and 80 t·ha−1 (B0, B10, B40 and B80, respectively). N2O and CH4 emissions were monitored by a closed-chamber method in the water-unsaturated tobacco (UT) and water-saturated rice (SR) seasons during the 2015 planting season. The soil pH increased from 5.4 in the control to 6.1 in the soil amended with biochar at 80 t·ha−1 in the UT season. During both the UT and SR seasons, with biochar amendment at 40 and 80 t·ha−1, the soil bulk density (BD) decreased, while the soil organic matter (SOM) and available potassium (Av. K) contents increased. N2O flux was significantly greater in UT than in SR in the controls but decreased with the application of biochar during both the UT and SR seasons. The cumulative CH4 emission decreased with the rate of biochar application and the methanotroph pmoA gene copy number in soils and increased with the methanogenic archaea 16Sr DNA gene copy number in soils during the rice-cropping season. These results indicated that biochar amendment could decrease methanogenic archaea and increase of methanotroph pmoA gene, which are the mechanistic origin for CH4 reduction.
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16
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Deng Y, Che R, Wang F, Conrad R, Dumont M, Yun J, Wu Y, Hu A, Fang J, Xu Z, Cui X, Wang Y. Upland Soil Cluster Gamma dominates methanotrophic communities in upland grassland soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 670:826-836. [PMID: 30921716 DOI: 10.1016/j.scitotenv.2019.03.299] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 03/19/2019] [Accepted: 03/19/2019] [Indexed: 05/25/2023]
Abstract
Aerobic methanotrophs in upland soils consume atmospheric methane, serving as a critical counterbalance to global warming; however, the biogeographic distribution patterns of their abundance and community composition are poorly understood, especial at a large scale. In this study, soils were sampled from 30 grasslands across >2000 km on the Qinghai-Tibetan Plateau to determine the distribution patterns of methanotrophs and their driving factors at a regional scale. Methanotroph abundance and community composition were analyzed using quantitative PCR and Illumina Miseq sequencing of pmoA genes, respectively. The pmoA gene copies ranged from 8.2 × 105 to 1.1 × 108 per gram dry soil. Among the 30 grassland soil samples, Upland Soil Cluster Gamma (USCγ) dominated the methanotroph communities in 26 samples. Jasper Ridge Cluster (JR3) was the most dominant methanotrophic cluster in two samples; while Methylocystis, cluster FWs, and Methylobacter were abundant in other two wet soil samples. Interestingly, reanalyzing the pmoA genes sequencing data from existing publications suggested that USCγ was also the main methanotrophic cluster in grassland soils in other regions, especially when their mean annual precipitation was <500 mm. Canonical Analysis of Principal Coordinates including all soil samples indicated that the methanotrophic community composition was significantly correlated with local environmental factors, among which mean annual precipitation and pH showed the strongest correlations. Variance partitioning analysis showed that environmental factors and spatial distance were significant factors affecting the community structure of methanotrophs, and environmental properties were more important factors. Collectively, these findings indicate that atmospheric methane may be mainly oxidized by USCγ in upland soils. They also highlight the key role of water availability and pH in determining the abundance and community profiles of grassland soil methanotrophs.
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Affiliation(s)
- Yongcui Deng
- School of Geography, Nanjing Normal University, 210023 Nanjing, China
| | - Rongxiao Che
- Institute of International Rivers and Eco-security, Yunnan University, 650091 Kunming, China; University of the Chinese Academy of Sciences, 100049 Beijing, China; Environmental Futures Research Institute, School of Environment and Science, Griffith University, Brisbane 4111, Australia
| | - Fang Wang
- University of the Chinese Academy of Sciences, 100049 Beijing, China; Environmental Futures Research Institute, School of Environment and Science, Griffith University, Brisbane 4111, Australia
| | - Ralf Conrad
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Straße 10, 35043 Marburg, Germany
| | - Marc Dumont
- Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Juanli Yun
- Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Yibo Wu
- Ningbo University, 315211 Ningbo, China
| | - Ang Hu
- Hunan Agricultural University, 410128 Changsha, China
| | - Jie Fang
- School of Geography, Nanjing Normal University, 210023 Nanjing, China
| | - Zhihong Xu
- Environmental Futures Research Institute, School of Environment and Science, Griffith University, Brisbane 4111, Australia
| | - Xiaoyong Cui
- University of the Chinese Academy of Sciences, 100049 Beijing, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, 100101 Beijing, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085 Beijing, China.
| | - Yanfen Wang
- University of the Chinese Academy of Sciences, 100049 Beijing, China
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17
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18
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Bodelier PLE, Pérez G, Veraart AJ, Krause SMB. Methanotroph Ecology, Environmental Distribution and Functioning. METHANOTROPHS 2019. [DOI: 10.1007/978-3-030-23261-0_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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19
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Bradford LM, Vestergaard G, Táncsics A, Zhu B, Schloter M, Lueders T. Transcriptome-Stable Isotope Probing Provides Targeted Functional and Taxonomic Insights Into Microaerobic Pollutant-Degrading Aquifer Microbiota. Front Microbiol 2018; 9:2696. [PMID: 30483229 PMCID: PMC6243674 DOI: 10.3389/fmicb.2018.02696] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/23/2018] [Indexed: 12/21/2022] Open
Abstract
While most studies using RNA-stable isotope probing (SIP) to date have focused on ribosomal RNA, the detection of 13C-labeled mRNA has rarely been demonstrated. This approach could alleviate some of the major caveats of current non-target environmental “omics.” Here, we demonstrate the feasibility of total RNA-SIP in an experiment where hydrocarbon-degrading microbes from a BTEX-contaminated aquifer were studied in microcosms with 13C-labeled toluene under microoxic conditions. From the total sequencing reads (∼30 mio. reads per density-resolved RNA fraction), an average of 1.2% of reads per sample were identified as non-rRNA, including mRNA. Members of the Rhodocyclaceae (including those related to Quatrionicoccus spp.) were most abundant and enriched in 13C-rRNA, while well-known aerobic degraders such as Pseudomonas spp. remained unlabeled. Transcripts related to cell motility, secondary metabolite formation and xenobiotics degradation were highly labeled with 13C. mRNA of phenol hydroxylase genes were highly labeled and abundant, while other transcripts of toluene-activation were not detected. Clear labeling of catechol 2,3-dioxygenase transcripts supported previous findings that some of these extradiol dioxygenases were adapted to low oxygen concentrations. We introduce a novel combination of total RNA-SIP with calculation of transcript-specific enrichment factors (EFs) in 13C-RNA, enabling a targeted approach to process-relevant gene expression in complex microbiomes.
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Affiliation(s)
- Lauren M Bradford
- Institute of Groundwater Ecology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Gisle Vestergaard
- Section of Microbiology, University of Copenhagen, Copenhagen, Denmark.,Research Unit Comparative Microbiome Analysis, Helmholtz Zentrum München, Neuherberg, Germany
| | - András Táncsics
- Regional University Center of Excellence in Environmental Industry, Szent István University, Gödöllö, Hungary
| | - Baoli Zhu
- Institute of Groundwater Ecology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Michael Schloter
- Regional University Center of Excellence in Environmental Industry, Szent István University, Gödöllö, Hungary
| | - Tillmann Lueders
- Institute of Groundwater Ecology, Helmholtz Zentrum München, Neuherberg, Germany
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20
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Methanotrophy across a natural permafrost thaw environment. ISME JOURNAL 2018; 12:2544-2558. [PMID: 29955139 PMCID: PMC6155033 DOI: 10.1038/s41396-018-0065-5] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 11/09/2022]
Abstract
The fate of carbon sequestered in permafrost is a key concern for future global warming as this large carbon stock is rapidly becoming a net methane source due to widespread thaw. Methane release from permafrost is moderated by methanotrophs, which oxidise 20-60% of this methane before emission to the atmosphere. Despite the importance of methanotrophs to carbon cycling, these microorganisms are under-characterised and have not been studied across a natural permafrost thaw gradient. Here, we examine methanotroph communities from the active layer of a permafrost thaw gradient in Stordalen Mire (Abisko, Sweden) spanning three years, analysing 188 metagenomes and 24 metatranscriptomes paired with in situ biogeochemical data. Methanotroph community composition and activity varied significantly as thaw progressed from intact permafrost palsa, to partially thawed bog and fully thawed fen. Thirteen methanotroph population genomes were recovered, including two novel genomes belonging to the uncultivated upland soil cluster alpha (USCα) group and a novel potentially methanotrophic Hyphomicrobiaceae. Combined analysis of porewater δ13C-CH4 isotopes and methanotroph abundances showed methane oxidation was greatest below the oxic-anoxic interface in the bog. These results detail the direct effect of thaw on autochthonous methanotroph communities, and their consequent changes in population structure, activity and methane moderation potential.
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21
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Pratscher J, Vollmers J, Wiegand S, Dumont MG, Kaster A. Unravelling the Identity, Metabolic Potential and Global Biogeography of the Atmospheric Methane-Oxidizing Upland Soil Cluster α. Environ Microbiol 2018; 20:1016-1029. [PMID: 29314604 PMCID: PMC6849597 DOI: 10.1111/1462-2920.14036] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 02/06/2023]
Abstract
Understanding of global methane sources and sinks is a prerequisite for the design of strategies to counteract global warming. Microbial methane oxidation in soils represents the largest biological sink for atmospheric methane. However, still very little is known about the identity, metabolic properties and distribution of the microbial group proposed to be responsible for most of this uptake, the uncultivated upland soil cluster α (USCα). Here, we reconstructed a draft genome of USCα from a combination of targeted cell sorting and metagenomes from forest soil, providing the first insights into its metabolic potential and environmental adaptation strategies. The 16S rRNA gene sequence recovered was distinctive and suggests this crucial group as a new genus within the Beijerinckiaceae, close to Methylocapsa. Application of a fluorescently labelled suicide substrate for the particulate methane monooxygenase enzyme (pMMO) coupled to 16S rRNA fluorescence in situ hybridisation (FISH) allowed for the first time a direct link of the high-affinity activity of methane oxidation to USCα cells in situ. Analysis of the global biogeography of this group further revealed its presence in previously unrecognized habitats, such as subterranean and volcanic biofilm environments, indicating a potential role of these environments in the biological sink for atmospheric methane.
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Affiliation(s)
| | - John Vollmers
- Institute for Biological Interfaces (IBG5), Karlsruhe Institute of TechnologyKarlsruheGermany
| | - Sandra Wiegand
- Department of MicrobiologyInstitute for Water and Wetland Research, Faculty of Science, Radboud UniversityNijmegenThe Netherlands
| | - Marc G. Dumont
- Biological SciencesUniversity of SouthamptonSouthamptonUK
| | - Anne‐Kristin Kaster
- Institute for Biological Interfaces (IBG5), Karlsruhe Institute of TechnologyKarlsruheGermany
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22
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Lueders T, Dumont MG, Bradford L, Manefield M. RNA-stable isotope probing: from carbon flow within key microbiota to targeted transcriptomes. Curr Opin Biotechnol 2016; 41:83-89. [PMID: 27269505 DOI: 10.1016/j.copbio.2016.05.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 04/27/2016] [Accepted: 05/05/2016] [Indexed: 10/21/2022]
Abstract
Stable isotope probing of RNA has enthused researchers right from its first introduction in 2002. The concept of a labelling-based detection of process-targeted microbes independent of cellular replication or growth has allowed for a much more direct handle on functionally relevant microbiota than by labelling of other biomarkers. This has led to a widespread application of the technology, and breakthroughs in our understanding of carbon flow in natural microbiomes, autotrophic and heterotrophic physiologies, microbial food webs, host-microbe interactions and environmental biotechnology. Recent studies detecting labelled mRNA demonstrate that RNA-SIP is not limited to the analysis of rRNA, but is currently developing towards an approach for accessing targeted transcriptomes. In combination with next-generation sequencing and other methodological advances, RNA-SIP will continue to deliver invaluable insights into the functioning of microbial communities.
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Affiliation(s)
- Tillmann Lueders
- Helmholtz Zentrum München - German Research Center for Environmental Health, Institute for Groundwater Ecology, Neuherberg, Germany.
| | - Marc G Dumont
- Centre for Biological Sciences (CfBS), University of Southampton, Southampton, United Kingdom
| | - Lauren Bradford
- Helmholtz Zentrum München - German Research Center for Environmental Health, Institute for Groundwater Ecology, Neuherberg, Germany
| | - Mike Manefield
- Centre for Marine Bioinnovation, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
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23
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Hofmann K, Pauli H, Praeg N, Wagner AO, Illmer P. Methane-cycling microorganisms in soils of a high-alpine altitudinal gradient. FEMS Microbiol Ecol 2016; 92:fiw009. [PMID: 26790465 DOI: 10.1093/femsec/fiw009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2016] [Indexed: 11/13/2022] Open
Abstract
Methanogens and methanotrophs play unique roles as producers and consumers of the greenhouse gas methane (CH4) in soils, respectively. Here, we aimed to reveal whether and to which extent methane-cyclers occur in high-alpine soils, and to assess their spatial distribution along an altitudinal gradient (2700-3500 m) in the Austrian Alps at sites located within the alpine (2700-2900 m), the alpine-nival (3000-3100 m) and the nival belts (3200-3500 m). Methanococcales and Methanocella spp. were most abundant among all quantified methanogenic guilds, whereas Methanosarcinales were not detected in the studied soil. The detected methanogens seem to be capable of persisting despite a highly oxic low-temperature environment. Methanogenic and methanotrophic activities and abundances of methanotrophs, Methanococcales and Methanocella spp. declined with altitude. Methanogenic and methanotrophic abundances were best explained by mean annual soil temperature and dissolved organic carbon, respectively. Alpine belt soils harbored significantly more methane-cyclers than those of the nival belt, indicating some influence of plant cover. Our results show that methanogens are capable of persisting in high-alpine cold soils and might help to understand future changes of these environments caused by climate warming.
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Affiliation(s)
- Katrin Hofmann
- Institute of Microbiology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Harald Pauli
- Institute for Interdisciplinary Mountain Research, Austrian Academy of Sciences and Center for Global Change and Sustainability, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Nadine Praeg
- Institute of Microbiology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Andreas O Wagner
- Institute of Microbiology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Paul Illmer
- Institute of Microbiology, University of Innsbruck, 6020 Innsbruck, Austria
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Knief C. Diversity and Habitat Preferences of Cultivated and Uncultivated Aerobic Methanotrophic Bacteria Evaluated Based on pmoA as Molecular Marker. Front Microbiol 2015; 6:1346. [PMID: 26696968 PMCID: PMC4678205 DOI: 10.3389/fmicb.2015.01346] [Citation(s) in RCA: 259] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/16/2015] [Indexed: 01/06/2023] Open
Abstract
Methane-oxidizing bacteria are characterized by their capability to grow on methane as sole source of carbon and energy. Cultivation-dependent and -independent methods have revealed that this functional guild of bacteria comprises a substantial diversity of organisms. In particular the use of cultivation-independent methods targeting a subunit of the particulate methane monooxygenase (pmoA) as functional marker for the detection of aerobic methanotrophs has resulted in thousands of sequences representing "unknown methanotrophic bacteria." This limits data interpretation due to restricted information about these uncultured methanotrophs. A few groups of uncultivated methanotrophs are assumed to play important roles in methane oxidation in specific habitats, while the biology behind other sequence clusters remains still largely unknown. The discovery of evolutionary related monooxygenases in non-methanotrophic bacteria and of pmoA paralogs in methanotrophs requires that sequence clusters of uncultivated organisms have to be interpreted with care. This review article describes the present diversity of cultivated and uncultivated aerobic methanotrophic bacteria based on pmoA gene sequence diversity. It summarizes current knowledge about cultivated and major clusters of uncultivated methanotrophic bacteria and evaluates habitat specificity of these bacteria at different levels of taxonomic resolution. Habitat specificity exists for diverse lineages and at different taxonomic levels. Methanotrophic genera such as Methylocystis and Methylocaldum are identified as generalists, but they harbor habitat specific methanotrophs at species level. This finding implies that future studies should consider these diverging preferences at different taxonomic levels when analyzing methanotrophic communities.
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Affiliation(s)
- Claudia Knief
- Institute of Crop Science and Resource Conservation – Molecular Biology of the Rhizosphere, University of BonnBonn, Germany
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25
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Ho A, Reim A, Kim SY, Meima-Franke M, Termorshuizen A, de Boer W, van der Putten WH, Bodelier PLE. Unexpected stimulation of soil methane uptake as emergent property of agricultural soils following bio-based residue application. GLOBAL CHANGE BIOLOGY 2015; 21:3864-79. [PMID: 25975568 DOI: 10.1111/gcb.12974] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 05/01/2015] [Indexed: 05/11/2023]
Abstract
Intensification of agriculture to meet the global food, feed, and bioenergy demand entail increasing re-investment of carbon compounds (residues) into agro-systems to prevent decline of soil quality and fertility. However, agricultural intensification decreases soil methane uptake, reducing, and even causing the loss of the methane sink function. In contrast to wetland agricultural soils (rice paddies), the methanotrophic potential in well-aerated agricultural soils have received little attention, presumably due to the anticipated low or negligible methane uptake capacity in these soils. Consequently, a detailed study verifying or refuting this assumption is still lacking. Exemplifying a typical agricultural practice, we determined the impact of bio-based residue application on soil methane flux, and determined the methanotrophic potential, including a qualitative (diagnostic microarray) and quantitative (group-specific qPCR assays) analysis of the methanotrophic community after residue amendments over 2 months. Unexpectedly, after amendments with specific residues, we detected a significant transient stimulation of methane uptake confirmed by both the methane flux measurements and methane oxidation assay. This stimulation was apparently a result of induced cell-specific activity, rather than growth of the methanotroph population. Although transient, the heightened methane uptake offsets up to 16% of total gaseous CO2 emitted during the incubation. The methanotrophic community, predominantly comprised of Methylosinus may facilitate methane oxidation in the agricultural soils. While agricultural soils are generally regarded as a net methane source or a relatively weak methane sink, our results show that methane oxidation rate can be stimulated, leading to higher soil methane uptake. Hence, even if agriculture exerts an adverse impact on soil methane uptake, implementing carefully designed management strategies (e.g. repeated application of specific residues) may compensate for the loss of the methane sink function following land-use change.
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Affiliation(s)
- Adrian Ho
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708, PB Wageningen, The Netherlands
| | - Andreas Reim
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Straβe 10, D-35043, Marburg, Germany
| | - Sang Yoon Kim
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708, PB Wageningen, The Netherlands
| | - Marion Meima-Franke
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708, PB Wageningen, The Netherlands
| | - Aad Termorshuizen
- SoilCares Research, Binnenhaven 5, 6709, PD Wageningen, The Netherlands
| | - Wietse de Boer
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708, PB Wageningen, The Netherlands
| | - Wim H van der Putten
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708, PB Wageningen, The Netherlands
- Laboratory of Nematology, Wageningen University and Research Centre (WUR), PO Box 8123, 6700, ES Wageningen, The Netherlands
| | - Paul L E Bodelier
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708, PB Wageningen, The Netherlands
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Leng L, Chang J, Geng K, Lu Y, Ma K. Uncultivated Methylocystis Species in Paddy Soil Include Facultative Methanotrophs that Utilize Acetate. MICROBIAL ECOLOGY 2015; 70:88-96. [PMID: 25475784 DOI: 10.1007/s00248-014-0540-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 11/21/2014] [Indexed: 06/04/2023]
Abstract
Methanotrophs are crucial in regulating methane emission from rice field systems. Type II methanotrophs in particular are often observed in high abundance in paddy soil. Some cultivated species of Methylocystis are able to grow on acetate in the absence of methane. We hypothesize that the dominant type II methanotrophs in paddy soil might facultatively utilize acetate for growth, which we evaluate in the present study. The measurement of methane oxidation rates showed that the methanotrophic activity in paddy soil was inhibited by the addition of acetate compared to the continuous supplementation of methane, but the paddy soil maintained the methane oxidation capacity and recovered following methane supplementation. Terminal restriction fragment length polymorphism analysis (T-RFLP) combined with cloning and sequencing of pmoA genes showed that Methylocystis was enriched after incubation with added acetate, while the type I methanotrophs Methylocaldum/Methylococcus and Methylobacter were enriched by methane supplementation. A comparison of pmoA sequences obtained in this study with those in the public database indicated that they were globally widespread in paddy soils or in associated with rice roots. Furthermore, we performed stable isotope probing (SIP) of pmoA messenger RNA (mRNA) to investigate the assimilation of (13)C-acetate by paddy soil methanotrophs. RNA-SIP revealed that Methylocystis-related methanotrophs which shared the same genotype of the above enriched species were significantly labelled. It indicates that these methanotrophs actively assimilated the labelled acetate in paddy soil. Altogether, these results suggested that uncultivated Methylocystis species are facultative methanotrophs utilizing acetate as a secondary carbon source in paddy soil.
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Affiliation(s)
- Lingqin Leng
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
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27
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Lima AB, Muniz AW, Dumont MG. Activity and abundance of methane-oxidizing bacteria in secondary forest and manioc plantations of Amazonian Dark Earth and their adjacent soils. Front Microbiol 2014; 5:550. [PMID: 25374565 PMCID: PMC4205850 DOI: 10.3389/fmicb.2014.00550] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 10/02/2014] [Indexed: 12/20/2022] Open
Abstract
The oxidation of atmospheric CH4 in upland soils is mostly mediated by uncultivated groups of microorganisms that have been identified solely by molecular markers, such as the sequence of the pmoA gene encoding the β-subunit of the particulate methane monooxygenase enzyme. The objective of this work was to compare the activity and diversity of methanotrophs in Amazonian Dark Earth soil (ADE, Hortic Anthrosol) and their adjacent non-anthropic soil. Secondly, the effect of land use in the form of manioc cultivation was examined by comparing secondary forest and plantation soils. CH4 oxidation potentials were measured and the structure of the methanotroph communities assessed by quantitative PCR (qPCR) and amplicon pyrosequencing of pmoA genes. The oxidation potentials at low CH4 concentrations (10 ppm of volume) were relatively high in all the secondary forest sites of both ADE and adjacent soils. CH4 oxidation by the ADE soil only recently converted to a manioc plantation was also relatively high. In contrast, both the adjacent soils used for manioc cultivation and the ADE soil with a long history of agriculture displayed lower CH4 uptake rates. Amplicon pyrosequencing of pmoA genes indicated that USCα, Methylocystis and the tropical upland soil cluster (TUSC) were the dominant groups depending on the site. By qPCR analysis it was found that USCα pmoA genes, which are believed to belong to atmospheric CH4 oxidizers, were more abundant in ADE than adjacent soil. USCα pmoA genes were abundant in both forested and cultivated ADE soil, but were below the qPCR detection limit in manioc plantations of adjacent soil. The results indicate that ADE soils can harbor high abundances of atmospheric CH4 oxidizers and are potential CH4 sinks, but as in other upland soils this activity can be inhibited by the conversion of forest to agricultural plantations.
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Affiliation(s)
- Amanda B Lima
- Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology Marburg, Germany
| | - Aleksander W Muniz
- Department of Soil Microbiology and Biogeochemistry, Brazilian Agricultural Research Corporation Manaus, Brazil
| | - Marc G Dumont
- Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology Marburg, Germany
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Genomic and transcriptomic analyses of the facultative methanotroph Methylocystis sp. strain SB2 grown on methane or ethanol. Appl Environ Microbiol 2014; 80:3044-52. [PMID: 24610846 DOI: 10.1128/aem.00218-14] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A minority of methanotrophs are able to utilize multicarbon compounds as growth substrates in addition to methane. The pathways utilized by these microorganisms for assimilation of multicarbon compounds, however, have not been explicitly examined. Here, we report the draft genome of the facultative methanotroph Methylocystis sp. strain SB2 and perform a detailed transcriptomic analysis of cultures grown with either methane or ethanol. Evidence for use of the canonical methane oxidation pathway and the serine cycle for carbon assimilation from methane was obtained, as well as for operation of the complete tricarboxylic acid (TCA) cycle and the ethylmalonyl-coenzyme A (EMC) pathway. Experiments with Methylocystis sp. strain SB2 grown on methane revealed that genes responsible for the first step of methane oxidation, the conversion of methane to methanol, were expressed at a significantly higher level than those for downstream oxidative transformations, suggesting that this step may be rate limiting for growth of this strain with methane. Further, transcriptomic analyses of Methylocystis sp. strain SB2 grown with ethanol compared to methane revealed that on ethanol (i) expression of the pathway of methane oxidation and the serine cycle was significantly reduced, (ii) expression of the TCA cycle dramatically increased, and (iii) expression of the EMC pathway was similar. Based on these data, it appears that Methylocystis sp. strain SB2 converts ethanol to acetyl-coenzyme A, which is then funneled into the TCA cycle for energy generation or incorporated into biomass via the EMC pathway. This suggests that some methanotrophs have greater metabolic flexibility than previously thought and that operation of multiple pathways in these microorganisms is highly controlled and integrated.
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Dumont MG, Pommerenke B, Casper P. Using stable isotope probing to obtain a targeted metatranscriptome of aerobic methanotrophs in lake sediment. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:757-764. [PMID: 24115627 DOI: 10.1111/1758-2229.12078] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Revised: 04/23/2013] [Accepted: 06/19/2013] [Indexed: 06/02/2023]
Abstract
In this study, we demonstrate the possibility of obtaining a targeted metatranscriptome from a functional group of microorganisms using a stable isotope probing (SIP) approach. Methanotrophs in lake sediment were labelled using (13)CH4, and both labelled and unlabelled-RNA were isolated and sequenced by 454 pyrosequencing. The unlabelled metatranscriptome had a large diversity of bacterial, archaeal, eukaryotic and viral sequences as expected from a diverse sediment community. In contrast, the labelled-RNA metatranscriptome was dominated by methanotroph sequences, particularly from Methylococcaceae. Transcripts of the methane monooxygenase genes pmoCAB were the most abundant in this metatranscriptome, and the pathway of methane oxidation to CO2 could be traced, as well as many steps in the ribulose monophosphate pathway for carbon assimilation. A high abundance of mRNA transcripts for proteins related to motility was detected, suggesting an importance for methanotrophs in lake sediments. This combination of SIP and metatranscriptomics should be broadly applicable, and will enhance the detection and identification of mRNA from target organisms.
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Affiliation(s)
- Marc G Dumont
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Straße 10, 35043, Marburg, Germany
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The (d)evolution of methanotrophy in the Beijerinckiaceae--a comparative genomics analysis. ISME JOURNAL 2013; 8:369-82. [PMID: 23985741 DOI: 10.1038/ismej.2013.145] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 07/17/2013] [Accepted: 07/24/2013] [Indexed: 01/26/2023]
Abstract
The alphaproteobacterial family Beijerinckiaceae contains generalists that grow on a wide range of substrates, and specialists that grow only on methane and methanol. We investigated the evolution of this family by comparing the genomes of the generalist organotroph Beijerinckia indica, the facultative methanotroph Methylocella silvestris and the obligate methanotroph Methylocapsa acidiphila. Highly resolved phylogenetic construction based on universally conserved genes demonstrated that the Beijerinckiaceae forms a monophyletic cluster with the Methylocystaceae, the only other family of alphaproteobacterial methanotrophs. Phylogenetic analyses also demonstrated a vertical inheritance pattern of methanotrophy and methylotrophy genes within these families. Conversely, many lateral gene transfer (LGT) events were detected for genes encoding carbohydrate transport and metabolism, energy production and conversion, and transcriptional regulation in the genome of B. indica, suggesting that it has recently acquired these genes. A key difference between the generalist B. indica and its specialist methanotrophic relatives was an abundance of transporter elements, particularly periplasmic-binding proteins and major facilitator transporters. The most parsimonious scenario for the evolution of methanotrophy in the Alphaproteobacteria is that it occurred only once, when a methylotroph acquired methane monooxygenases (MMOs) via LGT. This was supported by a compositional analysis suggesting that all MMOs in Alphaproteobacteria methanotrophs are foreign in origin. Some members of the Beijerinckiaceae subsequently lost methanotrophic functions and regained the ability to grow on multicarbon energy substrates. We conclude that B. indica is a recidivist multitroph, the only known example of a bacterium having completely abandoned an evolved lifestyle of specialized methanotrophy.
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Sullivan BW, Selmants PC, Hart SC. Does dissolved organic carbon regulate biological methane oxidation in semiarid soils? GLOBAL CHANGE BIOLOGY 2013; 19:2149-2157. [PMID: 23526765 DOI: 10.1111/gcb.12201] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 11/18/2013] [Accepted: 01/30/2013] [Indexed: 06/02/2023]
Abstract
In humid ecosystems, the rate of methane (CH4 ) oxidation by soil-dwelling methane-oxidizing bacteria (MOB) is controlled by soil texture and soil water holding capacity, both of which limit the diffusion of atmospheric CH4 into the soil. However, it remains unclear whether these same mechanisms control CH4 oxidation in more arid soils. This study was designed to measure the proximate controls of potential CH4 oxidation in semiarid soils during different seasons. Using a unique and well-constrained 3-million-year-old semiarid substrate age gradient, we were able to hold state factors constant while exploring the relationship between seasonal potential CH4 oxidation rates and soil texture, soil water holding capacity, and dissolved organic carbon (DOC). We measured unexpectedly higher rates of potential CH4 oxidation in the wet season than the dry season. Although other studies have attributed low CH4 oxidation rates in dry soils to desiccation of MOB, we present several lines of evidence that this may be inaccurate. We found that soil DOC concentration explained CH4 oxidation rates better than soil physical factors that regulate the diffusion of CH4 from the atmosphere into the soil. We show evidence that MOB facultatively incorporated isotopically labeled glucose into their cells, and MOB utilized glucose in a pattern among our study sites that was similar to wet-season CH4 oxidation rates. This evidence suggests that DOC, which is utilized by MOB in other environments with varying effects on CH4 oxidation rates, may be an important regulator of CH4 oxidation rates in semiarid soils. Our collective understanding of the facultative use of DOC by MOB is still in its infancy, but our results suggest it may be an important factor controlling CH4 oxidation in soils from dry ecosystems.
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