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Liu B, Ahnemann H, Arlotti D, Huyghebaert B, Cuperus F, Tebbe CC. Impact of diversified cropping systems and fertilization strategies on soil microbial abundance and functional potentials for nitrogen cycling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 932:172954. [PMID: 38723956 DOI: 10.1016/j.scitotenv.2024.172954] [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: 02/16/2024] [Revised: 04/09/2024] [Accepted: 05/01/2024] [Indexed: 05/12/2024]
Abstract
Diversified cropping systems and fertilization strategies were proposed to enhance the abundance and diversity of the soil microbiome, thereby stabilizing their beneficial services for maintaining soil fertility and supporting plant growth. Here, we assessed across three different long-term field experiments in Europe (Netherlands, Belgium, Northern Germany) whether diversified cropping systems and fertilization strategies also affect their functional gene abundance. Soil DNA was analyzed by quantitative PCR for quantifying bacteria, archaea and fungi as well as functional genes related to nitrogen (N) transformations; including bacterial and archaeal nitrification (amoA-bac,arch), three steps of the denitrification process (nirK, nirS and nosZ-cladeI,II) and N2 assimilation (nifH), respectively. Crop diversification and fertilization strategies generally enhanced soil total carbon (C), N and microbial abundance, but with variation between sites. Overall effects of diversified cropping systems and fertilization strategies on functional genes were much stronger than on the abundance of bacteria, archaea and fungi. The legume-based cropping systems showed great potential not only in stimulating the growth of N-fixing microorganisms but also in boosting downstream functional potentials for N cycling. The sorghum-based intercropping system suppressed soil ammonia oxidizing prokaryotes. N fertilization reduced the abundance of nitrifiers and denitrifiers except for ammonia-oxidizing bacteria, while the application of the synthetic nitrification inhibitor DMPP combined with mineral N reduced growth of both ammonia-oxidizing bacteria and archaea. In conclusion, this study demonstrates a strong impact of diversified agricultural practices on the soil microbiome and their functional potentials mediating N transformations.
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Affiliation(s)
- Bei Liu
- Thünen Institute of Biodiversity, Bundesallee 65, D-38116 Braunschweig, Germany
| | - Hauke Ahnemann
- Chamber of Agriculture, Lower Saxony, Vor dem Zoll 2, D-31582 Nienburg, Germany
| | - Donatienne Arlotti
- Walloon agricultural Research Centre; Soil, water and integrated production Unit, 4, rue du Bordia, B-5030 Gembloux, Belgium
| | - Bruno Huyghebaert
- Walloon agricultural Research Centre; Soil, water and integrated production Unit, 4, rue du Bordia, B-5030 Gembloux, Belgium
| | - Fogelina Cuperus
- Wageningen University & Research, Edelhertweg 1, NL-8219 PH Lelystad, Netherlands
| | - Christoph C Tebbe
- Thünen Institute of Biodiversity, Bundesallee 65, D-38116 Braunschweig, Germany.
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2
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Intrator N, Jayakumar A, Ward BB. Aquatic nitrous oxide reductase gene ( nosZ) phylogeny and environmental distribution. Front Microbiol 2024; 15:1407573. [PMID: 38835481 PMCID: PMC11148229 DOI: 10.3389/fmicb.2024.1407573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 05/06/2024] [Indexed: 06/06/2024] Open
Abstract
Nitrous oxide (N2O) is a potent greenhouse gas and a major cause of ozone depletion. One-third of atmospheric N2O originates in aquatic environments. Reduction of N2O to dinitrogen gas (N2) requires the nitrous oxide reductase enzyme, which is encoded by the gene nosZ. Organisms that contain nosZ are the only known biological sinks of N2O and are found in diverse genera and a wide range of environments. The two clades of nosZ (Clade I and II) contain great diversity, making it challenging to study the population structure and distribution of nosZ containing organisms in the environment. A database of over 11,000 nosZ sequences was compiled from NCBI (representing diverse aquatic environments) and unpublished sequences and metagenomes (primarily from oxygen minimum zones, OMZs, where N2O levels are often elevated). Sequences were clustered into archetypes based on DNA and amino acid sequence identity and their clade, phylogeny, and environmental source were determined. Further analysis of the source and environmental distribution of the sequences showed strong habitat separation between clades and phylogeny. Although there are more Clade I nosZ genes in the compilation, Clade II is more diverse phylogenetically and has a wider distribution across environmental sources. On the other hand, Clade I nosZ genes are predominately found within marine sediment and are primarily from the phylum Pseudonomonadota. The majority of the sequences analyzed from marine OMZs represented distinct phylotypes between different OMZs showing that the nosZ gene displays regional and environmental separation. This study expands the known diversity of nosZ genes and provides a clearer picture of how the clades and phylogeny of nosZ organisms are distributed across diverse environments.
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Affiliation(s)
- Naomi Intrator
- Department of Geosciences, Princeton University, Princeton, NJ, United States
| | - Amal Jayakumar
- Department of Geosciences, Princeton University, Princeton, NJ, United States
| | - Bess B Ward
- Department of Geosciences, Princeton University, Princeton, NJ, United States
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3
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Chen KH, Feng J, Bodelier PLE, Yang Z, Huang Q, Delgado-Baquerizo M, Cai P, Tan W, Liu YR. Metabolic coupling between soil aerobic methanotrophs and denitrifiers in rice paddy fields. Nat Commun 2024; 15:3471. [PMID: 38658559 PMCID: PMC11043409 DOI: 10.1038/s41467-024-47827-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 04/15/2024] [Indexed: 04/26/2024] Open
Abstract
Paddy fields are hotspots of microbial denitrification, which is typically linked to the oxidation of electron donors such as methane (CH4) under anoxic and hypoxic conditions. While several anaerobic methanotrophs can facilitate denitrification intracellularly, whether and how aerobic CH4 oxidation couples with denitrification in hypoxic paddy fields remains virtually unknown. Here we combine a ~3300 km field study across main rice-producing areas of China and 13CH4-DNA-stable isotope probing (SIP) experiments to investigate the role of soil aerobic CH4 oxidation in supporting denitrification. Our results reveal positive relationships between CH4 oxidation and denitrification activities and genes across various climatic regions. Microcosm experiments confirm that CH4 and methanotroph addition promote gene expression involved in denitrification and increase nitrous oxide emissions. Moreover, 13CH4-DNA-SIP analyses identify over 70 phylotypes harboring genes associated with denitrification and assimilating 13C, which are mostly belonged to Rubrivivax, Magnetospirillum, and Bradyrhizobium. Combined analyses of 13C-metagenome-assembled genomes and 13C-metabolomics highlight the importance of intermediates such as acetate, propionate and lactate, released during aerobic CH4 oxidation, for the coupling of CH4 oxidation with denitrification. Our work identifies key microbial taxa and pathways driving coupled aerobic CH4 oxidation and denitrification, with important implications for nitrogen management and greenhouse gas regulation in agroecosystems.
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Affiliation(s)
- Kang-Hua Chen
- National Key Laboratory of Agricultural Microbiology and College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
- State Environmental Protection Key Laboratory of Soil Health and Green Remediation and Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jiao Feng
- National Key Laboratory of Agricultural Microbiology and College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
- State Environmental Protection Key Laboratory of Soil Health and Green Remediation and Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Paul L E Bodelier
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO Box 50, 6700 AB, Wageningen, The Netherlands
| | - Ziming Yang
- Department of Chemistry, Oakland University, Rochester, MI, 48309, USA
| | - Qiaoyun Huang
- National Key Laboratory of Agricultural Microbiology and College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
- State Environmental Protection Key Laboratory of Soil Health and Green Remediation and Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, 430070, China
| | - Manuel Delgado-Baquerizo
- Laboratorio de Biodiversidad y Funcionamiento Ecosistémico, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Sevilla, 41012, Spain
| | - Peng Cai
- National Key Laboratory of Agricultural Microbiology and College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
- State Environmental Protection Key Laboratory of Soil Health and Green Remediation and Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wenfeng Tan
- State Environmental Protection Key Laboratory of Soil Health and Green Remediation and Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yu-Rong Liu
- National Key Laboratory of Agricultural Microbiology and College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
- State Environmental Protection Key Laboratory of Soil Health and Green Remediation and Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, 430070, China.
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Xiang H, Hong Y, Wu J, Wang Y, Ye F, Ye J, Lu J, Long A. Denitrification contributes to N 2O emission in paddy soils. Front Microbiol 2023; 14:1218207. [PMID: 37396352 PMCID: PMC10313071 DOI: 10.3389/fmicb.2023.1218207] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 06/01/2023] [Indexed: 07/04/2023] Open
Abstract
Denitrification is vital to nitrogen removal and N2O release in ecosystems; in this regard, paddy soils exhibit strong denitrifying ability. However, the underlying mechanism of N2O emission from denitrification in paddy soils is yet to be elucidated. In this study, the potential N2O emission rate, enzymatic activity for N2O production and reduction, gene abundance, and community composition during denitrification were investigated using the 15N isotope tracer technique combined with slurry incubation, enzymatic activity detection, quantitative polymerase chain reaction (qPCR), and metagenomic sequencing. Results of incubation experiments showed that the average potential N2O emission rates were 0.51 ± 0.20 μmol⋅N⋅kg-1⋅h-1, which constituted 2.16 ± 0.85% of the denitrification end-products. The enzymatic activity for N2O production was 2.77-8.94 times than that for N2O reduction, indicating an imbalance between N2O production and reduction. The gene abundance ratio of nir to nosZ from qPCR results further supported the imbalance. Results of metagenomic analysis showed that, although Proteobacteria was the common phylum for denitrification genes, other dominant community compositions varied for different denitrification genes. Gammaproteobacteria and other phyla containing the norB gene without nosZ genes, including Actinobacteria, Planctomycetes, Desulfobacterota, Cyanobacteria, Acidobacteria, Bacteroidetes, and Myxococcus, may contribute to N2O emission from paddy soils. Our results suggest that denitrification is highly modular, with different microbial communities collaborating to complete the denitrification process, thus resulting in an emission estimation of 13.67 ± 5.44 g N2O⋅m-2⋅yr-1 in surface paddy soils.
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Affiliation(s)
- Hua Xiang
- State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Institute of Environmental Research at Greater Bay Area, Ministry of Education, Guangzhou University, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yiguo Hong
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Institute of Environmental Research at Greater Bay Area, Ministry of Education, Guangzhou University, Guangzhou, China
| | - Jiapeng Wu
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Institute of Environmental Research at Greater Bay Area, Ministry of Education, Guangzhou University, Guangzhou, China
| | - Yu Wang
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Institute of Environmental Research at Greater Bay Area, Ministry of Education, Guangzhou University, Guangzhou, China
| | - Fei Ye
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Institute of Environmental Research at Greater Bay Area, Ministry of Education, Guangzhou University, Guangzhou, China
| | - Jiaqi Ye
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Institute of Environmental Research at Greater Bay Area, Ministry of Education, Guangzhou University, Guangzhou, China
| | - Jing Lu
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Institute of Environmental Research at Greater Bay Area, Ministry of Education, Guangzhou University, Guangzhou, China
| | - Aimin Long
- State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
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5
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Bhaduri D, Sihi D, Bhowmik A, Verma BC, Munda S, Dari B. A review on effective soil health bio-indicators for ecosystem restoration and sustainability. Front Microbiol 2022; 13:938481. [PMID: 36060788 PMCID: PMC9428492 DOI: 10.3389/fmicb.2022.938481] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 06/29/2022] [Indexed: 11/30/2022] Open
Abstract
Preventing degradation, facilitating restoration, and maintaining soil health is fundamental for achieving ecosystem stability and resilience. A healthy soil ecosystem is supported by favorable components in the soil that promote biological productivity and provide ecosystem services. Bio-indicators of soil health are measurable properties that define the biotic components in soil and could potentially be used as a metric in determining soil functionality over a wide range of ecological conditions. However, it has been a challenge to determine effective bio-indicators of soil health due to its temporal and spatial resolutions at ecosystem levels. The objective of this review is to compile a set of effective bio-indicators for developing a better understanding of ecosystem restoration capabilities. It addresses a set of potential bio-indicators including microbial biomass, respiration, enzymatic activity, molecular gene markers, microbial metabolic substances, and microbial community analysis that have been responsive to a wide range of ecosystem functions in agricultural soils, mine deposited soil, heavy metal contaminated soil, desert soil, radioactive polluted soil, pesticide polluted soil, and wetland soils. The importance of ecosystem restoration in the United Nations Sustainable Development Goals was also discussed. This review identifies key management strategies that can help in ecosystem restoration and maintain ecosystem stability.
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Affiliation(s)
- Debarati Bhaduri
- ICAR-National Rice Research Institute, Cuttack, India
- *Correspondence: Debarati Bhaduri
| | - Debjani Sihi
- Department of Environmental Sciences, Emory University, Atlanta, GA, United States
| | - Arnab Bhowmik
- Department of Natural Resources and Environmental Design, North Carolina Agricultural and Technical State University, Greensboro, NC, United States
- Arnab Bhowmik
| | - Bibhash C. Verma
- Central Rainfed Upland Rice Research Station (ICAR-NRRI), Hazaribagh, India
| | | | - Biswanath Dari
- Agriculture and Natural Resources, Cooperative Extension at North Carolina Agricultural and Technical State University, Greensboro, NC, United States
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6
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Cai M, Hong Y, Wu J, Moore SS, Vamerali T, Ye F, Wang Y. Nitrate Addition Increases the Activity of Microbial Nitrogen Removal in Freshwater Sediment. Microorganisms 2022; 10:microorganisms10071429. [PMID: 35889148 PMCID: PMC9317351 DOI: 10.3390/microorganisms10071429] [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: 06/15/2022] [Revised: 07/08/2022] [Accepted: 07/13/2022] [Indexed: 12/04/2022] Open
Abstract
Denitrification and anammox occur widely in aquatic ecosystems serving vital roles in nitrogen pollution removal. However, small waterbodies are sensitive to external influences; stormwater runoff carrying nutrients and oxygen, flows into waterbodies resulting in a disruption of geochemical and microbial processes. Nonetheless, little is known about how these short-term external inputs affect the microbial processes of nitrogen removal in small waterbodies. To investigate the effects of NO3−, NH4+, dissolved oxygen (DO) and organic C on microbial nitrogen removal in pond sediments, regulation experiments have been conducted using slurry incubation experiments and 15N tracer techniques in this study. It was demonstrated the addition of NO3− (50 to 800 μmol L−1) significantly promoted denitrification rates, as expected by Michaelis-Menten kinetics. Ponds with higher NO3− concentrations in the overlying water responded more greatly to NO3− additions. Moreover, N2O production was also promoted by such an addition of NO3−. Denitrification was significantly inhibited by the elevation of DO concentration from 0 to 2 mg L−1, after which no significant increase in inhibition was observed. Denitrification rates increased when organic C was introduced. Due to the abundant NH4+ in pond sediments, the addition demonstrated little influence on nitrogen removal. Moreover, anammox rates showed no significant changes to any amendment.
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Affiliation(s)
- Min Cai
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China; (M.C.); (Y.H.); (J.W.)
| | - Yiguo Hong
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China; (M.C.); (Y.H.); (J.W.)
| | - Jiapeng Wu
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China; (M.C.); (Y.H.); (J.W.)
| | - Selina Sterup Moore
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, 35122 Padova, Italy; (S.S.M.); (T.V.)
| | - Teofilo Vamerali
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, 35122 Padova, Italy; (S.S.M.); (T.V.)
| | - Fei Ye
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China; (M.C.); (Y.H.); (J.W.)
- Correspondence: (F.Y.); (Y.W.)
| | - Yu Wang
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China; (M.C.); (Y.H.); (J.W.)
- Correspondence: (F.Y.); (Y.W.)
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Ku Y, Lei Y, Han X, Peng J, Zhu Y, Zhao Z. Spatial Patterns and Composition Traits of Soil Microbial Nitrogen-Metabolism Genes in the Robinia pseudoacacia Forests at a Regional Scale. Front Microbiol 2022; 13:918134. [PMID: 35814641 PMCID: PMC9263705 DOI: 10.3389/fmicb.2022.918134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/02/2022] [Indexed: 11/16/2022] Open
Abstract
Microbial-driven processes related to the nitrogen-metabolism (N-metabolism) in soil are critical for ecosystem functioning and stability. There are spatial patterns of microbial-mediated nitrogen processes, but we still lack an overview of the soil N-metabolism genes of single nitrogen-fixing tree species pure forests at a regional scale. Here, we investigated the spatial variation and drivers of microbial N-metabolism genes in the rhizosphere soil of Robinia pseudoacacia on the Loess Plateau by metagenomic technology. We found that the distance-decay of soil N functional gene similarities in Robinia pseudoacacia forests on the Loess Plateau spanning a geographic distance of 230 km was significant (p < 0.001). The gene composition and co-occurrence patterns in the process of soil microbial N-metabolism were very different, and they were mainly driven by soil pH and MAP (mean annual precipitation). The proportion of positive links and edges co-occurrence networks between N functional genes increased with increasing pH, suggesting that increasing pH promoted connections between functional genes. The relative frequencies of N-metabolism pathways were consistent on the Loess Plateau, the abundance of ammonia assimilation pathway was highest, and the abundance of the nitrogen fixation pathway was the lowest; only the abundance of the nitrogen fixation pathway was not significantly different. The bacterial and archaeal communities involved in soil nitrogen metabolism were significantly different. Structural equation modeling showed that decreases in soil pH and MAP mainly affected the increase in nitrogen functional gene abundance through an increase in the diversity of N-metabolism microorganisms. In conclusion, this study provides a baseline for biogeographic studies of soil microbe functional genes.
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Affiliation(s)
- Yongli Ku
- Key Comprehensive Laboratory of Forestry, Northwest A&F University, Yangling, China
| | - Yuting Lei
- Key Comprehensive Laboratory of Forestry, Northwest A&F University, Yangling, China
| | - Xiaoting Han
- Key Comprehensive Laboratory of Forestry, Northwest A&F University, Yangling, China
| | - Jieying Peng
- Key Comprehensive Laboratory of Forestry, Northwest A&F University, Yangling, China
| | - Ying Zhu
- Key Laboratory of Soil and Water Conservation and Ecological Restoration of State Forestry and Grassland Administration, Shaanxi Academy of Forestry, Xi’an, China
| | - Zhong Zhao
- Key Comprehensive Laboratory of Forestry, Northwest A&F University, Yangling, China
- Key Laboratory of Silviculture on the Loess Plateau State Forestry Administration, Northwest A&F University, Yangling, China
- *Correspondence: Zhong Zhao, ;
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Changes in Ammonia-Oxidizing Archaea and Bacterial Communities and Soil Nitrogen Dynamics in Response to Long-Term Nitrogen Fertilization. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19052732. [PMID: 35270425 PMCID: PMC8910298 DOI: 10.3390/ijerph19052732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 11/16/2022]
Abstract
Ammonia oxidizing archaea (AOA) and bacteria (AOB) mediate a crucial step in nitrogen (N) metabolism. The effect of N fertilizer rates on AOA and AOB communities is less studied in the wheat-fallow system from semi-arid areas. Based on a 17-year wheat field experiment, we explored the effect of five N fertilizer rates (0, 52.5, 105, 157.5, and 210 kg ha-1 yr-1) on the AOA and AOB community composition. This study showed that the grain yield of wheat reached the maximum at 105 kg N ha-1 (49% higher than control), and no further significant increase was observed at higher N rates. With the increase of N, AOA abundance decreased in a regular trend from 4.88 × 107 to 1.05 × 107 copies g-1 dry soil, while AOB abundance increased from 3.63 × 107 up to a maximum of 8.24 × 107 copies g-1 dry soil with the N105 treatment (105 kg N ha-1 yr-1). Application rates of N fertilizer had a more significant impact on the AOB diversity than on AOA diversity, and the highest AOB diversity was found under the N105 treatment in this weak alkaline soil. The predominant phyla of AOA and AOB were Thaumarchaeota and Proteobacteria, respectively, and higher N treatment (N210) resulted in a significant decrease in the relative abundance of genus Nitrosospira. In addition, AOA and AOB communities were significantly associated with grain yield of wheat, soil potential nitrification activity (PNA), and some soil physicochemical parameters such as pH, NH4-N, and NO3-N. Among them, soil moisture was the most influential edaphic factor for structuring the AOA community and NH4-N for the AOB community. Overall, 105 kg N ha-1 yr-1 was optimum for the AOB community and wheat yield in the semi-arid area.
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Zhang M, Daraz U, Sun Q, Chen P, Wei X. Denitrifier abundance and community composition linked to denitrification potential in river sediments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:51928-51939. [PMID: 33990922 DOI: 10.1007/s11356-021-14348-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 05/06/2021] [Indexed: 06/12/2023]
Abstract
Denitrification in river sediments plays a very important role in removing nitrogen in aquatic ecosystem. To gain insight into the key factors driving denitrification at large spatial scales, a total of 135 sediment samples were collected from Huaihe River and its branches located in the northern of Anhui province. Bacterial community composition and denitrifying functional genes (nirS, nirK, and nosZ) were measured by high-throughput sequencing and real-time PCR approaches. Potential denitrification rate (PDR) was measured by acetylene inhibition method, which varied from 0.01 to 15.69 μg N g-1 h-1. The sequencing results based on 16S rRNA gene found that the main denitrification bacterial taxa included Bacillus, Thiobacillus, Acinetobacter, Halomonas, Denitratisoma, Pseudomonas, Rhodanobacter, and Thauera. Therein, Thiobacillus might play key roles in the denitrification. Total nitrogen and N:P ratio were the only chemical factors related with all denitrification genes. Furthermore, nirS gene abundance could be more susceptible to environmental parameters compared with nirK and nosZ genes. Canonical correspondence analysis indicated that NO3-, NO2-, NH4+ and IP had the significant impacts on the nirS-encoding bacterial community and spatial distributions. There was a significantly positive correlation between Thiobacillus and nirS gene. We considered that higher numbers of nosZ appeared in nutrient rich sediments. More strikingly, PDR was positively correlated with the abundance of three functional genes. Random forest analysis showed that NH4+ was the most powerful predictor of PDR. These findings can yield practical and important reference for the bioremediation or evaluation of wetland systems.
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Affiliation(s)
- Mingzhu Zhang
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, Anhui Province, China
- Key Laboratory of Wetland Ecological Protection and Restoration, Hefei, China
- Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, China
| | - Umar Daraz
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, Anhui Province, China
| | - Qingye Sun
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, Anhui Province, China.
- Key Laboratory of Wetland Ecological Protection and Restoration, Hefei, China.
- Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, China.
| | - Piaoxue Chen
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, Anhui Province, China
- Key Laboratory of Wetland Ecological Protection and Restoration, Hefei, China
- Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, China
| | - Xuhao Wei
- School of Resources and Environmental Engineering, Anhui University, Hefei, 230601, Anhui Province, China
- Key Laboratory of Wetland Ecological Protection and Restoration, Hefei, China
- Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, China
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10
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Abstract
Conservation agriculture practices that promote soil health have distinct and lasting effects on microbial populations involved with soil nitrogen (N) cycling. In particular, using a leguminous winter cover crop (hairy vetch) promoted the expression of key functional genes involved in soil N cycling, equaling or exceeding the effects of inorganic N fertilizer. Soil microbial transformations of nitrogen (N) can be affected by soil health management practices. Here, we report in situ seasonal dynamics of the population size (gene copy abundances) and functional activity (transcript copy abundances) of five bacterial genes involved in soil N cycling (ammonia-oxidizing bacteria [AOB] amoA, nifH, nirK, nirS, and nosZ) in a long-term continuous cotton production system under different management practices (cover crops, tillage, and inorganic N fertilization). Hairy vetch (Vicia villosa Roth), a leguminous cover crop, most effectively promoted the expression of N cycle genes, which persisted after cover crop termination throughout the growing season. Moreover, we observed similarly high or even higher N cycle gene transcript abundances under vetch with no fertilizer as no cover crop with N fertilization throughout the cover crop peak and cotton growing seasons (April, May, and October). Further, both the gene and transcript abundances of amoA and nosZ were positively correlated to soil nitrous oxide (N2O) emissions. We also found that the abundances of amoA genes and transcripts both positively correlated to field and incubated net nitrification rates. Together, our results revealed relationships between microbial functional capacity and activity and in situ soil N transformations under different agricultural seasons and soil management practices. IMPORTANCE Conservation agriculture practices that promote soil health have distinct and lasting effects on microbial populations involved with soil nitrogen (N) cycling. In particular, using a leguminous winter cover crop (hairy vetch) promoted the expression of key functional genes involved in soil N cycling, equaling or exceeding the effects of inorganic N fertilizer. Hairy vetch also left a legacy on soil nutrient capacity by promoting the continued activity of N cycling microbes after cover crop termination and into the main growing season. By examining both genes and transcripts involved in soil N cycling, we showed different responses of functional capacity (i.e., gene abundances) and functional activity (i.e., transcript abundances) to agricultural seasons and management practices, adding to our understanding of the effects of soil health management practices on microbial ecology.
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Huang R, Zeng J, Zhao D, Yong B, Yu Z. Co-association of Two nir Denitrifiers Under the Influence of Emergent Macrophytes. MICROBIAL ECOLOGY 2020; 80:809-821. [PMID: 32577778 DOI: 10.1007/s00248-020-01545-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Diverse microorganisms perform similar metabolic process in biogeochemical cycles, whereas they are found of highly genomic differentiation. Biotic interactions should be considered in any community survey of these functional groups, as they contribute to community assembly and ultimately alter ecosystem properties. Current knowledge has mainly been achieved based on functional community characterized by a single gene using co-occurrence network analysis. Biotic interactions between functionally equivalent microorganisms, however, have received much less attention. Herein, we propose the nirK- and nirS-type denitrifier communities represented by these two nitrite reductase (nir)-encoding genes, as model communities to investigate the potential interactions of two nir denitrifiers. We evaluated co-occurrence patterns and co-association network structures of nir denitrifier community from an emergent macrophyte-dominated riparian zone of highly active denitrification in Lake Taihu, China. We found a more segregated pattern in combined nir communities than in individual communities. Network analyses revealed a modularized structure of associating nir denitrifiers. An increased proportion of negative associations among combined communities relative to those of individual communities indicated potential interspecific competition between nirK and nirS denitrifiers. pH and NH4+-N were the most important factors driving co-occurrence and mutual exclusion between nirK and nirS denitrifiers. We also showed the topological importance of nirK denitrifiers acting as module hubs for constructing entire association networks. We revealed previously unexplored co-association relationships between nirK and nirS denitrifiers, which were previously neglected in network analyses of individual communities. Using nir denitrifier community as a model, these findings would be helpful for us to understand the biotic interactions and mechanisms underlying how functional groups co-exist in performing biogeochemical cycles.
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Affiliation(s)
- Rui Huang
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
| | - Jin Zeng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Dayong Zhao
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
| | - Bin Yong
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
| | - Zhongbo Yu
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
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12
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Bak F, Nybroe O, Zheng B, Badawi N, Hao X, Nicolaisen MH, Aamand J. Preferential flow paths shape the structure of bacterial communities in a clayey till depth profile. FEMS Microbiol Ecol 2020; 95:5288339. [PMID: 30649315 PMCID: PMC6397044 DOI: 10.1093/femsec/fiz008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/25/2019] [Indexed: 12/13/2022] Open
Abstract
Preferential flow paths in subsurface soils serve as transport routes for water, dissolved organic matter and oxygen. Little is known about bacterial communities in flow paths or in subsoils below ∼4 m. We compared communities from preferential flow paths (biopores, fractures and sand lenses) with those in adjacent matrix sediments of clayey till from the plough layer to a depth of 6 m. 16S rRNA gene-targeted community analysis showed bacterial communities of greater abundance and diversity in flow paths than in matrix sediments at all depths. Deep fracture communities contained a higher relative abundance of aerobes and plant material decomposers like Nitrospirae, Acidobacteria and Planctomycetes than adjacent matrix sediments. Similarly, analyses of the relative abundances of archaeal amoA, nirK and dsrB genes indicated transition from aerobic to anaerobic nitrogen and sulphur cycling at greater depth in preferential flow paths than in matrix sediments. Preferential flow paths in the top 260 cm contained more indicator operational taxonomic units from the plough layer community than the matrix sediments. This study indicates that the availability of oxygen and organic matter and downward transport of bacteria shape bacterial communities in preferential flow paths, and suggests that their lifestyles differ from those of bacteria in matrix communities.
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Affiliation(s)
- Frederik Bak
- Geological Survey of Denmark and Greenland, Copenhagen, Denmark.,University of Copenhagen, Department of Plant and Environmental Sciences, Copenhagen, Denmark
| | - Ole Nybroe
- University of Copenhagen, Department of Plant and Environmental Sciences, Copenhagen, Denmark
| | - Bangxiao Zheng
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Nora Badawi
- Geological Survey of Denmark and Greenland, Copenhagen, Denmark
| | - Xiuli Hao
- University of Copenhagen, Department of Plant and Environmental Sciences, Copenhagen, Denmark.,Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan, China
| | | | - Jens Aamand
- Geological Survey of Denmark and Greenland, Copenhagen, Denmark
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13
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Assessing Soil Acidification of Croplands in the Poyang Lake Basin of China from 2012 to 2018. SUSTAINABILITY 2020. [DOI: 10.3390/su12083072] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Soil acidification, caused by intensified fertilizer application and acid deposition, has threatened the sustainability of agricultural ecosystems and soil quality in parts of China since the 1980s. However, little is known about the spatio-temporal change of soil pH in cropland at a large basin scale. Poyang Lake Basin of China was selected as the study area to identify the spatio-temporal change of cropland pH and detect potential soil acidification factors. A total of 507 and 503 topsoil samples were collected in 2012 and 2018, respectively, and methods including one-way analysis of variance (ANOVA), Pearson’s correlation analyses, and Inverse Distance Weighted (IDW) were applied. Results showed that soil pH ranged from 3.96 to 7.95 in 2012 and from 3.34 to 8.19 in 2018, with most samples being acidic (pH < 7) in both sets of data. The two soil datasets showed a significant decline (p < 0.05) of 0.1 pH units over the past six years and several soil samples that exhibited obvious uptrends in the groups of pH < 4.5 and 4.5–5.0 from 2012 to 2018. Overall, the distribution patterns of pH at the two sampling dates were similar, whereas local details of the pH spatial distribution patterns differed. While we found a significant correlation (p < 0.05) between soil pH and aspect, elevation and slope showed no significant correlation with pH. ANOVA showed that pH values in the water density (river or lake network density) range of 6.27–19.94 were significantly higher (p < 0.05) than the other water densities. Large amounts of precipitation with low pH values were found to significantly influence soil pH, whereas N-fertilizer inputs exerted limited effects on soil pH over the entire study area. These findings provided new insights on soil acidification assessment and potential factor detection at the basin scale.
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14
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Avşar C, Aras ES. Quantification of denitrifier genes population size and its relationship with environmental factors. Arch Microbiol 2020; 202:1181-1192. [PMID: 32076734 DOI: 10.1007/s00203-020-01826-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 01/28/2020] [Accepted: 01/30/2020] [Indexed: 10/25/2022]
Abstract
The objectives of this study were to use real-time PCR for culture-independent quantification of the copy numbers of 16S rRNA and denitrification functional genes, and also the relationships between gene copy numbers and soil physicochemical properties. In this study, qPCR analysis of the soil samples showed 16S rRNA, nirS, nirK, nosZI and nosZII average densities of 3.0 × 108, 2.25 × 107, 2.9 × 105, 4.0 × 106 and 1.75 × 107 copies per gram of dry soil, respectively. In addition, the abundances of (nirS + nirK), nosZI and nosZII relative to 16S rRNA genes were 1.4-34.1%, 0.06-3.95% and 1.3-39%, respectively, confirming the low proportion of denitrifiers to total bacteria in soil. This showed that the non-denitrifying nosZII-type bacteria may contribute significantly to N2O consumption in the soil. Furthermore, the shifts in abundance and diversity of the total bacteria and denitrification functional gene copy numbers correlated significantly with the various soil factors. It is the first study in Turkey about the population size of denitrification functional genes in different soil samples. It also aims to draw attention to nitrous oxide-associated global warming.
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Affiliation(s)
- Cumhur Avşar
- Department of Biology, Faculty of Arts and Sciences, Sinop University, Sinop, Turkey.
| | - E Sümer Aras
- Department of Biology, Faculty of Science, Ankara University, Ankara, Turkey
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15
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Zhang Y, Ji G. Quantitative responses of potential nitrification and denitrification rates to the size of microbial communities in rice paddy soils. CHEMOSPHERE 2018; 211:970-977. [PMID: 30119028 DOI: 10.1016/j.chemosphere.2018.08.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 08/08/2018] [Accepted: 08/10/2018] [Indexed: 06/08/2023]
Abstract
Nitrification and denitrification are important to nitrogen balance in agricultural ecosystems. However, the molecular drivers and limiting steps for these microbial processes in rice paddy soils are not well understood. Here, we assessed soil properties and abundances of functional genes affiliated with nitrification (amoA and nxrA), denitrification (nirS, nirK and nosZ), nitrate reduction (narG and napA) processes, and measured potential nitrification and denitrification rates (PNRs and PDRs) at 15 sites in Xiamen, China. The soil properties imposed indirect impacts on the potential rates by mediating the relative abundances of microbial communities. No significant relationships between the size of microbial communities and the potential rates were observed. Instead, we found the variables that best explained the variations in the PNRs and PDRs were AOB/nirS and (nirK + nirS)/nosZ, respectively. The PNRs were mainly limited by the relative strength of two steps, namely bacterial ammonium oxidation and nitrite into nitric oxide reduction, whereas the PDRs were mainly limited by the relative strength of the second and last denitrification steps. These results indicated that the dynamics of microbial communities based on the relative gene abundances are valuable in integrating fluctuations in soil physicochemical properties and are indictive of potential rates in paddy soils. Results of this study contribute to our quantitative understanding of the relative importance of soil physicochemical and biological factors in driving microbial potential in paddy soils.
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Affiliation(s)
- Yan Zhang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Guodong Ji
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China
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16
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Conthe M, Wittorf L, Kuenen JG, Kleerebezem R, Hallin S, van Loosdrecht MCM. Growth yield and selection of nosZ clade II types in a continuous enrichment culture of N 2 O respiring bacteria. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:239-244. [PMID: 29457693 DOI: 10.1111/1758-2229.12630] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Nitrous oxide (N2 O) reducing microorganisms may be key in the mitigation of N2 O emissions from managed ecosystems. However, there is still no clear understanding of the physiological and bioenergetic implications of microorganisms possessing either of the two N2 O reductase genes (nosZ), clade I and the more recently described clade II type nosZ. It has been suggested that organisms with nosZ clade II have higher growth yields and a lower affinity constant (Ks ) for N2 O. We compared N2 O reducing communities with different nosZI/nosZII ratios selected in chemostat enrichment cultures, inoculated with activated sludge, fed with N2 O as a sole electron acceptor and growth limiting factor and acetate as electron donor. From the sequencing of the 16S rRNA gene, FISH and quantitative PCR of nosZ and nir genes, we concluded that betaproteobacterial denitrifying organisms dominated the enrichments with members within the family Rhodocyclaceae being highly abundant. When comparing cultures with different nosZI/nosZII ratios, we did not find support for (i) a more energy conserving N2 O respiration pathway in nosZ clade II systems, as reflected in the growth yield per mole of substrate, or (ii) a higher affinity for N2 O, defined by μmax /Ks , in organisms with nosZ clade II.
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Affiliation(s)
- Monica Conthe
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Lea Wittorf
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - J Gijs Kuenen
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Sara Hallin
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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17
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Abstract
Microorganisms drive much of the Earth's nitrogen (N) cycle, but we still lack a global overview of the abundance and composition of the microorganisms carrying out soil N processes. To address this gap, we characterized the biogeography of microbial N traits, defined as eight N-cycling pathways, using publically available soil metagenomes. The relative frequency of N pathways varied consistently across soils, such that the frequencies of the individual N pathways were positively correlated across the soil samples. Habitat type, soil carbon, and soil N largely explained the total N pathway frequency in a sample. In contrast, we could not identify major drivers of the taxonomic composition of the N functional groups. Further, the dominant genera encoding a pathway were generally similar among habitat types. The soil samples also revealed an unexpectedly high frequency of bacteria carrying the pathways required for dissimilatory nitrate reduction to ammonium, a little-studied N process in soil. Finally, phylogenetic analysis showed that some microbial groups seem to be N-cycling specialists or generalists. For instance, taxa within the Deltaproteobacteria encoded all eight N pathways, whereas those within the Cyanobacteria primarily encoded three pathways. Overall, this trait-based approach provides a baseline for investigating the relationship between microbial diversity and N cycling across global soils.
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18
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Genomics and Ecology of Novel N 2O-Reducing Microorganisms. Trends Microbiol 2017; 26:43-55. [PMID: 28803698 DOI: 10.1016/j.tim.2017.07.003] [Citation(s) in RCA: 185] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/29/2017] [Accepted: 07/14/2017] [Indexed: 11/22/2022]
Abstract
Microorganisms with the capacity to reduce the greenhouse gas nitrous oxide (N2O) to harmless dinitrogen gas are receiving increased attention due to increasing N2O emissions (and our need to mitigate climate change) and to recent discoveries of novel N2O-reducing bacteria and archaea. The diversity of denitrifying and nondenitrifying microorganisms with capacity for N2O reduction was recently shown to be greater than previously expected. A formerly overlooked group (clade II) in the environment include a large fraction of nondenitrifying N2O reducers, which could be N2O sinks without major contribution to N2O formation. We review the recent advances about fundamental understanding of the genomics, physiology, and ecology of N2O reducers and the importance of these findings for curbing N2O emissions.
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19
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Spatial Abundance, Diversity, and Activity of Ammonia-Oxidizing Bacteria in Coastal Sediments of the Liaohe Estuary. Curr Microbiol 2017; 74:632-640. [PMID: 28293807 DOI: 10.1007/s00284-017-1226-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 02/27/2017] [Indexed: 12/26/2022]
Abstract
Ammonia-oxidizing bacteria (AOB) play an important role in nitrification in estuaries. The aim of this study was to examine the spatial abundance, diversity, and activity of AOB in coastal sediments of the Liaohe Estuary using quantitative PCR, high-throughput sequencing of the amoA gene coding the ammonia monooxygenase enzyme active subunit, and sediment slurry incubation experiments. AOB abundance ranged from 8.54 × 104 to 5.85 × 106 copies g-1 of wet sediment weight and exhibited an increasing trend from the Liaohe Estuary to the open coastal zone. Potential nitrification rates (PNRs) ranged from 0.1 to 336.8 nmol N g-1 day-1 along the estuary to the coastal zone. Log AOB abundance and PNRs were significantly positively correlated. AOB richness decreased from the estuary to the coastal zone. High-throughput sequencing analysis indicated that the majority of amoA gene sequences fell within the Nitrosomonas and Nitrosomonas-like clade, and only a few sequences were clustered within the Nitrosospira clade. This finding indicates that the Nitrosomonas-related lineage may be more adaptable to the specific conditions in this estuary than the Nitrosospira lineage. Sites with high nitrification rates were located in the southern open region and were dominated by the Nitrosomonas-like lineage, whereas the Nitrosospira lineage was found primarily in the northern estuary mouth sites with low nitrification rates. Thus, nitrification potentials in Liaohe estuarine sediments in the southern open region were greater than those in the northern estuary mouth, and the Nitrosomonas-related lineage might play a more important role than the Nitrosospira lineage in nitrification in this estuary.
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20
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Yashiro E, Pinto-Figueroa E, Buri A, Spangenberg JE, Adatte T, Niculita-Hirzel H, Guisan A, van der Meer JR. Local Environmental Factors Drive Divergent Grassland Soil Bacterial Communities in the Western Swiss Alps. Appl Environ Microbiol 2016; 82:6303-6316. [PMID: 27542929 DOI: 10.1128/aem.01170-16.editor] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/28/2016] [Indexed: 05/22/2023] Open
Abstract
UNLABELLED Mountain ecosystems are characterized by a diverse range of climatic and topographic conditions over short distances and are known to shelter a high biodiversity. Despite important progress, still little is known on bacterial diversity in mountain areas. Here, we investigated soil bacterial biogeography at more than 100 sampling sites randomly stratified across a 700-km2 area with 2,200-m elevation gradient in the western Swiss Alps. Bacterial grassland communities were highly diverse, with 12,741 total operational taxonomic units (OTUs) across 100 sites and an average of 2,918 OTUs per site. Bacterial community structure was correlated with local climatic, topographic, and soil physicochemical parameters with high statistical significance. We found pH (correlated with % CaO and % mineral carbon), hydrogen index (correlated with bulk gravimetric water content), and annual average number of frost days during the growing season to be among the groups of the most important environmental drivers of bacterial community structure. In contrast, bacterial community structure was only weakly stratified as a function of elevation. Contrasting patterns were discovered for individual bacterial taxa. Acidobacteria responded both positively and negatively to pH extremes. Various families within the Bacteroidetes responded to available phosphorus levels. Different verrucomicrobial groups responded to electrical conductivity, total organic carbon, water content, and mineral carbon contents. Alpine grassland bacterial communities are thus highly diverse, which is likely due to the large variety of different environmental conditions. These results shed new light on the biodiversity of mountain ecosystems, which were already identified as potentially fragile to anthropogenic influences and climate change. IMPORTANCE This article addresses the question of how microbial communities in alpine regions are dependent on local climatic and soil physicochemical variables. We benefit from a unique 700-km2 study region in the western Swiss Alps region, which has been exhaustively studied for macro-organismal and fungal ecology, and for topoclimatic modeling of future ecological trends, but without taking into account soil bacterial diversity. Here, we present an in-depth biogeographical characterization of the bacterial community diversity in this alpine region across 100 randomly stratified sites, using 56 environmental variables. Our exhaustive sampling ensured the detection of ecological trends with high statistical robustness. Our data both confirm previously observed general trends and show many new detailed trends for a wide range of bacterial taxonomic groups and environmental parameters.
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Affiliation(s)
- Erika Yashiro
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Eric Pinto-Figueroa
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Aline Buri
- Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland
| | - Jorge E Spangenberg
- Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland
| | - Thierry Adatte
- Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland
| | - Hélène Niculita-Hirzel
- Institute for Work and Health, University of Lausanne and Geneva, Epalinges-Lausanne, Switzerland
| | - Antoine Guisan
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland
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21
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Local Environmental Factors Drive Divergent Grassland Soil Bacterial Communities in the Western Swiss Alps. Appl Environ Microbiol 2016; 82:6303-6316. [PMID: 27542929 DOI: 10.1128/aem.01170-16] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/28/2016] [Indexed: 02/01/2023] Open
Abstract
Mountain ecosystems are characterized by a diverse range of climatic and topographic conditions over short distances and are known to shelter a high biodiversity. Despite important progress, still little is known on bacterial diversity in mountain areas. Here, we investigated soil bacterial biogeography at more than 100 sampling sites randomly stratified across a 700-km2 area with 2,200-m elevation gradient in the western Swiss Alps. Bacterial grassland communities were highly diverse, with 12,741 total operational taxonomic units (OTUs) across 100 sites and an average of 2,918 OTUs per site. Bacterial community structure was correlated with local climatic, topographic, and soil physicochemical parameters with high statistical significance. We found pH (correlated with % CaO and % mineral carbon), hydrogen index (correlated with bulk gravimetric water content), and annual average number of frost days during the growing season to be among the groups of the most important environmental drivers of bacterial community structure. In contrast, bacterial community structure was only weakly stratified as a function of elevation. Contrasting patterns were discovered for individual bacterial taxa. Acidobacteria responded both positively and negatively to pH extremes. Various families within the Bacteroidetes responded to available phosphorus levels. Different verrucomicrobial groups responded to electrical conductivity, total organic carbon, water content, and mineral carbon contents. Alpine grassland bacterial communities are thus highly diverse, which is likely due to the large variety of different environmental conditions. These results shed new light on the biodiversity of mountain ecosystems, which were already identified as potentially fragile to anthropogenic influences and climate change. IMPORTANCE This article addresses the question of how microbial communities in alpine regions are dependent on local climatic and soil physicochemical variables. We benefit from a unique 700-km2 study region in the western Swiss Alps region, which has been exhaustively studied for macro-organismal and fungal ecology, and for topoclimatic modeling of future ecological trends, but without taking into account soil bacterial diversity. Here, we present an in-depth biogeographical characterization of the bacterial community diversity in this alpine region across 100 randomly stratified sites, using 56 environmental variables. Our exhaustive sampling ensured the detection of ecological trends with high statistical robustness. Our data both confirm previously observed general trends and show many new detailed trends for a wide range of bacterial taxonomic groups and environmental parameters.
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22
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Paranychianakis NV, Tsiknia M, Kalogerakis N. Pathways regulating the removal of nitrogen in planted and unplanted subsurface flow constructed wetlands. WATER RESEARCH 2016; 102:321-329. [PMID: 27379728 DOI: 10.1016/j.watres.2016.06.048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 06/22/2016] [Accepted: 06/23/2016] [Indexed: 06/06/2023]
Abstract
Single-stage constructed wetlands (CWs) are characterized by a low potential for N removal. Understanding the pathways regulating N cycling as well as their dependence on environmental variables might improve the potential of CWs for N removal and results in more accurate simulation tools. In this study we employed qPCR targeting marker functional genes (amoA, nirK, nirS, clade I and II nosZ) or microorganisms (anammox) regulating key pathways of N cycling to unravel their relative importance. Furthermore, the influence of plant species on treatment performance was studied. Our findings indicated nitrification-denitrification as the principal route of N removal in CWs, while anammox did not have a strong contribution. Evidence was also arisen that ammonia oxidizing archaea (AOA) contributed on NH3 oxidation. Overall, plant species had a weak effect on the abundance of N functional genes (amoA of AOA), but it strongly affected the performance of CWs in terms of N removal in the following order: unplanted < Phragmites communis < Typha latifolia. These findings suggest that plant species stimulate N removal by upregulating the rates that the responsible biochemical pathways operate, probably by increasing O2 supply. In addition, our study revealed differences in indicators linked to N2O emissions. The abundance of clade II nosZ genes remained low across the season scaling down a strong contribution in the reduction of the emitted N2O. The increasing ratios of nosZ/Σnir and nirS/nirK with the progress of season indicate a shift in the composition of denitrifiers towards strains with a lower genetic potential for N2O release. Similar trends were observed among the treatments but the mechanisms differed. The planted treatments stimulated an increase in the ΣnosZ/Σnir ratio, while the unplanted an increase in the nirS/nirK ratio.
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Affiliation(s)
- Nikolaos V Paranychianakis
- School of Environmental Engineering, Technical University of Crete, Polytechnioupolis, 73100, Chania, Greece.
| | - Myrto Tsiknia
- School of Environmental Engineering, Technical University of Crete, Polytechnioupolis, 73100, Chania, Greece
| | - Nicolas Kalogerakis
- School of Environmental Engineering, Technical University of Crete, Polytechnioupolis, 73100, Chania, Greece
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