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Cuartero J, Querejeta JI, Prieto I, Frey B, Alguacil MM. Warming and rainfall reduction alter soil microbial diversity and co-occurrence networks and enhance pathogenic fungi in dryland soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 949:175006. [PMID: 39069184 DOI: 10.1016/j.scitotenv.2024.175006] [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: 06/03/2024] [Revised: 07/10/2024] [Accepted: 07/22/2024] [Indexed: 07/30/2024]
Abstract
In this 9-year manipulative field experiment, we examined the impacts of experimental warming (2 °C, W), rainfall reduction (30 % decrease in annual rainfall, RR), and their combination (W + RR) on soil microbial communities and native vegetation in a semi-arid shrubland in south-eastern Spain. Warming had strong negative effects on plant performance across five coexisting native shrub species, consistently reducing their aboveground biomass growth and long-term survival. The impacts of rainfall reduction on plant growth and survival were species-specific and more variable. Warming strongly altered the soil microbial community alpha-diversity and changed the co-occurrence network structure. The relative abundance of symbiotic arbuscular mycorrhizal fungi (AMF) increased under W and W + RR, which could help buffer the direct negative impacts of climate change on their host plants nutrition and enhance their resistance to heat and drought stress. Indicator microbial taxa analyses evidenced that the marked sequence abundance of many plant pathogenic fungi, such as Phaeoacremonium, Cyberlindnera, Acremonium, Occultifur, Neodevriesia and Stagonosporopsis, increased significantly in the W and W + RR treatments. Moreover, the relative abundance of fungal animal pathogens and mycoparasites in soil also increased significantly under climate warming. Our findings indicate that warmer and drier conditions sustained over several years can alter the soil microbial community structure, composition, and network topology. The projected warmer and drier climate favours pathogenic fungi, which could offset the benefits of increased AMF abundance under warming and further aggravate the severe detrimental impacts of increased abiotic stress on native vegetation performance and ecosystem services in drylands.
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Affiliation(s)
- J Cuartero
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland.
| | - J I Querejeta
- Departamento de Conservación de Suelos y Agua, Centro de Edafología y Biología Aplicada del Segura - Consejo Superior de Investigaciones Científicas, Murcia, Spain
| | - I Prieto
- Departamento de Conservación de Suelos y Agua, Centro de Edafología y Biología Aplicada del Segura - Consejo Superior de Investigaciones Científicas, Murcia, Spain; Area de Ecología, Facultad de Ciencias Biológicas y Ambientales, Departamento de Biodiversidad y Gestión Ambiental, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
| | - B Frey
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - M M Alguacil
- Departamento de Conservación de Suelos y Agua, Centro de Edafología y Biología Aplicada del Segura - Consejo Superior de Investigaciones Científicas, Murcia, Spain
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Deng F, Xie H, Zheng T, Yang Y, Bao X, He H, Zhang X, Liang C. Dynamic responses of soil microbial communities to seasonal freeze-thaw cycles in a temperate agroecosystem. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175228. [PMID: 39102954 DOI: 10.1016/j.scitotenv.2024.175228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 06/22/2024] [Accepted: 07/31/2024] [Indexed: 08/07/2024]
Abstract
Soil freeze-thaw cycles (FTCs) are common in temperate agricultural ecosystems during the non-growing season and are progressively influenced by climate change. The impact of these cycles on soil microbial communities, crucial for ecosystem functioning, varies under different agricultural management practices. Here, we investigated the dynamic changes in soil microbial communities in a Mollisol during seasonal FTCs and examined the effects of stover mulching and nitrogen fertilization. We revealed distinct responses between bacterial and fungal communities. The dominant bacterial phyla reacted differently to FTCs: for example, Proteobacteria responded opportunistically, Actinobacteria, Acidobacteria, Choroflexi and Gemmatimonadetes responded sensitively, and Saccharibacteria exhibited a tolerance response. In contrast, the fungal community composition remained relatively stable during FTCs, except for a decline in Glomeromycota. Certain bacterial OTUs acted as sensitive indicators of FTCs, forming keystone modules in the network that are closely linked to soil carbon, nitrogen content and potential functions. Additionally, neither stover mulching nor nitrogen fertilization significantly influenced microbial richness, diversity and potential functions. However, over time, more indicator species specific to these agricultural practices began to emerge within the networks and gradually occupied the central positions. Furthermore, our findings suggest that farming practices, by introducing keystone microbes and changing interspecies interactions (even without changing microbial richness and diversity), can enhance microbial community stability against FTC disturbances. Specifically, higher nitrogen input with stover removal promotes fungal stability during soil freezing, while lower nitrogen levels increase bacterial stability during soil thawing. Considering the fungal tolerance to FTCs, we recommend reducing nitrogen input for manipulating bacterial interactions, thereby enhancing overall microbial resilience to seasonal FTCs. In summary, our research reveals that microbial responses to seasonal FTCs are reshaped through land management to support ecosystem functions under environmental stress amid climate change.
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Affiliation(s)
- Fangbo Deng
- Key Lab of Conservation Tillage & Ecological Agriculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongtu Xie
- Key Lab of Conservation Tillage & Ecological Agriculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Tiantian Zheng
- Key Lab of Conservation Tillage & Ecological Agriculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Yali Yang
- Key Lab of Conservation Tillage & Ecological Agriculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Xuelian Bao
- Key Lab of Conservation Tillage & Ecological Agriculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Hongbo He
- Key Lab of Conservation Tillage & Ecological Agriculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Xudong Zhang
- Key Lab of Conservation Tillage & Ecological Agriculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Chao Liang
- Key Lab of Conservation Tillage & Ecological Agriculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
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Wang X, Wang Z, Chen F, Zhang Z, Fang J, Xing L, Zeng J, Zhang Q, Liu H, Liu W, Ren C, Yang G, Zhong Z, Zhang W, Han X. Deterministic assembly of grassland soil microbial communities driven by climate warming amplifies soil carbon loss. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171418. [PMID: 38460701 DOI: 10.1016/j.scitotenv.2024.171418] [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: 11/25/2023] [Revised: 02/27/2024] [Accepted: 02/29/2024] [Indexed: 03/11/2024]
Abstract
Perturbations in soil microbial communities caused by climate warming are expected to have a strong impact on biodiversity and future climate-carbon (C) feedback, especially in vulnerable habitats that are highly sensitive to environmental change. Here, we investigate the impact of four-year experimental warming on soil microbes and C cycling in the Loess Hilly Region of China. The results showed that warming led to soil C loss, mainly from labile C, and this C loss is associated with microbial response. Warming significantly decreased soil bacterial diversity and altered its community structure, especially increasing the abundance of heat-tolerant microorganisms, but had no effect on fungi. Warming also significantly increased the relative importance of homogeneous selection and decreased "drift" of bacterial and fungal communities. Moreover, warming decreased bacterial network stability but increased fungal network stability. Notably, the magnitude of soil C loss was significantly and positively correlated with differences in bacterial community characteristics under ambient and warming conditions, including diversity, composition, network stability, and community assembly. This result suggests that microbial responses to warming may amplify soil C loss. Combined, these results provide insights into soil microbial responses and C feedback in vulnerable ecosystems under climate warming scenarios.
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Affiliation(s)
- Xing Wang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Zhengchen Wang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Fang Chen
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Zhenjiao Zhang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Jingbo Fang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Liheng Xing
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Jia Zeng
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Qi Zhang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Hanyu Liu
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Weichao Liu
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Chengjie Ren
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Gaihe Yang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China
| | - Zekun Zhong
- Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Wei Zhang
- College of Grassland Agriculture, Northwest A&F University, Yangling 712100, Shaanxi, PR China.
| | - Xinhui Han
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, PR China.
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Yang X, Xu J, Wang H, Quan H, Yu H, Luan J, Wang D, Li Y, Lv D. Vertical distribution characteristics of soil organic carbon and vegetation types under different elevation gradients in Cangshan, Dali. PeerJ 2024; 12:e16686. [PMID: 38188153 PMCID: PMC10771771 DOI: 10.7717/peerj.16686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/26/2023] [Indexed: 01/09/2024] Open
Abstract
Background The Cangshan National Nature Reserve of Dali City was adopted as the research object to clarify the vertical distribution characteristics of soil organic carbon (SOC) and vegetation types at different elevations in western Yunnan. Methods The contents of SOC, light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), and water-soluble organic carbon (WSOC) in the 0-30 cm soil layer at different elevations (2,400, 2,600, 2,800, 3,000, 3,200, 3,400, and 3,600 m) were determined, and the above-ground vegetation types at different elevations were investigated. Results Results showed that the SOC content was the highest in 0-20 cm surface soil and gradually decreased with the deepening of the soil layer. It increased then decreased with the increase in elevation, and it peaked at 3,000 m. The LFOC content was between 1.28 and 7.3515 g kg-1. It exhibited a decreasing trend and little change in profile distribution. The HFOC content ranged between 12.9727 and 23.3708 g kg-1; it increased then decreased with the increase in profile depth. The WSOC content was between 235.5783 and 392.3925 mg kg-1, and the response sensitivity to elevation change was weak. With the increase in elevation, WSOC/SOC and LFOC/SOC showed a similar trend, whereas HFOC presented an opposite trend. This observation indicates that the active organic carbon content at 3,600 m was lower than that at 2,400 m, and the middle elevation was conducive to the storage of active organic carbon. Meanwhile, the physical and chemical properties of soil affected the distribution of organic carbon to a certain extent. The vegetation type survey showed that the above-ground dominant species within 2,400-2,800 m were Pinus yunnanensis and Pinus armandii. Many evergreen and mixed coniferous broadleaf forests were distributed from 3,000 m to 3,200 m. Species of Abies delavayi were mainly distributed from 3,400 m to 3,600 m. This research serves as a reference for the study of forest soil carbon stability in high-elevation areas and plays an important role in formulating reasonable land use management policies, protecting forest soil, reducing organic carbon loss, and investigating the carbon sequestration stability of forest ecosystems.
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Affiliation(s)
- Xue Yang
- College of Agronomy and Biological Sciences, Dali University, Dali, Yunnan, China
- Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, Yunnan, China
| | - Jianhong Xu
- College of Agronomy and Biological Sciences, Dali University, Dali, Yunnan, China
- Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, Yunnan, China
| | - Huifang Wang
- College of Agronomy and Biological Sciences, Dali University, Dali, Yunnan, China
- Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, Yunnan, China
| | - Hong Quan
- College of Agronomy and Biological Sciences, Dali University, Dali, Yunnan, China
- Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, Yunnan, China
| | - Huijuan Yu
- College of Agronomy and Biological Sciences, Dali University, Dali, Yunnan, China
- Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, Yunnan, China
| | - Junda Luan
- College of Agronomy and Biological Sciences, Dali University, Dali, Yunnan, China
- Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, Yunnan, China
| | - Dishan Wang
- College of Agronomy and Biological Sciences, Dali University, Dali, Yunnan, China
- Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, Yunnan, China
| | - Yuancheng Li
- College of Agronomy and Biological Sciences, Dali University, Dali, Yunnan, China
- Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, Yunnan, China
- Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Dongpeng Lv
- College of Agronomy and Biological Sciences, Dali University, Dali, Yunnan, China
- Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, Yunnan, China
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Feng M, Varliero G, Qi W, Stierli B, Edwards A, Robinson S, van der Heijden MGA, Frey B. Microbial dynamics in soils of the Damma glacier forefield show succession in the functional genetic potential. Environ Microbiol 2023; 25:3116-3138. [PMID: 37688461 DOI: 10.1111/1462-2920.16497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 08/08/2023] [Indexed: 09/10/2023]
Abstract
Glacier retreat is a visible consequence of climate change worldwide. Although taxonomic change of the soil microbiomes in glacier forefields have been widely documented, how microbial genetic potential changes along succession is little known. Here, we used shotgun metagenomics to analyse whether the soil microbial genetic potential differed between four stages of soil development (SSD) sampled along three transects in the Damma glacier forefield (Switzerland). The SSDs were characterized by an increasing vegetation cover, from barren soil, to biological soil crust, to sparsely vegetated soil and finally to vegetated soil. Results suggested that SSD significantly influenced microbial genetic potential, with the lowest functional diversity surprisingly occurring in the vegetated soils. Overall, carbohydrate metabolism and secondary metabolite biosynthesis genes overrepresented in vegetated soils, which could be partly attributed to plant-soil feedbacks. For C degradation, glycoside hydrolase genes enriched in vegetated soils, while auxiliary activity and carbohydrate esterases genes overrepresented in barren soils, suggested high labile C degradation potential in vegetated, and high recalcitrant C degradation potential in barren soils. For N-cycling, organic N degradation and synthesis genes dominated along succession, and gene families involved in nitrification were overrepresented in barren soils. Our study provides new insights into how the microbial genetic potential changes during soil formation along the Damma glacier forefield.
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Affiliation(s)
- Maomao Feng
- Rhizosphere Processes Group, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Gilda Varliero
- Rhizosphere Processes Group, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Weihong Qi
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
- Swiss Institute of Bioinformatics SIB, Geneva, Switzerland
| | - Beat Stierli
- Rhizosphere Processes Group, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Arwyn Edwards
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, UK
| | - Serina Robinson
- Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Dübendorf, Switzerland
| | - Marcel G A van der Heijden
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
- Plant-Soil Interactions, Agroscope, Zurich, Switzerland
| | - Beat Frey
- Rhizosphere Processes Group, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
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Touchette D, Gostinčar C, Whyte LG, Altshuler I. Lichen-associated microbial members are prevalent in the snow microbiome of a sub-arctic alpine tundra. FEMS Microbiol Ecol 2023; 99:fiad151. [PMID: 37977855 DOI: 10.1093/femsec/fiad151] [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: 04/27/2023] [Revised: 09/27/2023] [Accepted: 11/16/2023] [Indexed: 11/19/2023] Open
Abstract
Snow is the largest component of the cryosphere, with its cover and distribution rapidly decreasing over the last decade due to climate warming. It is imperative to characterize the snow (nival) microbial communities to better understand the role of microorganisms inhabiting these rapidly changing environments. Here, we investigated the core nival microbiome, the cultivable microbial members, and the microbial functional diversity of the remote Uapishka mountain range, a massif of alpine sub-arctic tundra and boreal forest. Snow samples were taken over a two-month interval along an altitude gradient with varying degree of anthropogenic traffic and vegetation cover. The core snow alpine tundra/boreal microbiome, which was present across all samples, constituted of Acetobacterales, Rhizobiales and Acidobacteriales bacterial orders, and of Mycosphaerellales and Lecanorales fungal orders, with the dominant fungal taxa being associated with lichens. The snow samples had low active functional diversity, with Richness values ranging from 0 to 19.5. The culture-based viable microbial enumeration ranged from 0 to 8.05 × 103 CFUs/mL. We isolated and whole-genome sequenced five microorganisms which included three fungi, one alga, and one potentially novel bacterium of the Lichenihabitans genus; all of which appear to be part of lichen-associated taxonomic clades.
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Affiliation(s)
- D Touchette
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, H9X 3V9, Canada
- River Ecosystems Laboratory, ALPOLE, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, CH-1950, Sion, Switzerland
| | - C Gostinčar
- University of Ljubljana, Department of Biology, Biotechnical Faculty, Ljubljana 1000, Slovenia
| | - L G Whyte
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, H9X 3V9, Canada
| | - I Altshuler
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, H9X 3V9, Canada
- MACE Laboratory, ALPOLE, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, CH-1950, Sion, Switzerland
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Han X, Beck K, Bürgmann H, Frey B, Stierli B, Frossard A. Synthetic oligonucleotides as quantitative PCR standards for quantifying microbial genes. Front Microbiol 2023; 14:1279041. [PMID: 37942081 PMCID: PMC10627841 DOI: 10.3389/fmicb.2023.1279041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 10/09/2023] [Indexed: 11/10/2023] Open
Abstract
Real-time quantitative PCR (qPCR) has been widely used to quantify gene copy numbers in microbial ecology. Despite its simplicity and straightforwardness, establishing qPCR assays is often impeded by the tedious process of producing qPCR standards by cloning the target DNA into plasmids. Here, we designed double-stranded synthetic DNA fragments from consensus sequences as qPCR standards by aligning microbial gene sequences (10-20 sequences per gene). Efficiency of standards from synthetic DNA was compared with plasmid standards by qPCR assays for different phylogenetic marker and functional genes involved in carbon (C) and nitrogen (N) cycling, tested with DNA extracted from a broad range of soils. Results showed that qPCR standard curves using synthetic DNA performed equally well to those from plasmids for all the genes tested. Furthermore, gene copy numbers from DNA extracted from soils obtained by using synthetic standards or plasmid standards were comparable. Our approach therefore demonstrates that a synthetic DNA fragment as qPCR standard provides comparable sensitivity and reliability to a traditional plasmid standard, while being more time- and cost-efficient.
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Affiliation(s)
- Xingguo Han
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Karin Beck
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Helmut Bürgmann
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Beat Frey
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Beat Stierli
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Aline Frossard
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
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Sannino C, Qi W, Rüthi J, Stierli B, Frey B. Distinct taxonomic and functional profiles of high Arctic and alpine permafrost-affected soil microbiomes. ENVIRONMENTAL MICROBIOME 2023; 18:54. [PMID: 37328770 DOI: 10.1186/s40793-023-00509-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 06/02/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Global warming is affecting all cold environments, including the European Alps and Arctic regions. Here, permafrost may be considered a unique ecosystem harboring a distinct microbiome. The frequent freeze-thaw cycles occurring in permafrost-affected soils, and mainly in the seasonally active top layers, modify microbial communities and consequently ecosystem processes. Although taxonomic responses of the microbiomes in permafrost-affected soils have been widely documented, studies about how the microbial genetic potential, especially pathways involved in C and N cycling, changes between active-layer soils and permafrost soils are rare. Here, we used shotgun metagenomics to analyze the microbial and functional diversity and the metabolic potential of permafrost-affected soil collected from an alpine site (Val Lavirun, Engadin area, Switzerland) and a High Arctic site (Station Nord, Villum Research Station, Greenland). The main goal was to discover the key genes abundant in the active-layer and permafrost soils, with the purpose to highlight the potential role of the functional genes found. RESULTS We observed differences between the alpine and High Arctic sites in alpha- and beta-diversity, and in EggNOG, CAZy, and NCyc datasets. In the High Arctic site, the metagenome in permafrost soil had an overrepresentation (relative to that in active-layer soil) of genes involved in lipid transport by fatty acid desaturate and ABC transporters, i.e. genes that are useful in preventing microorganisms from freezing by increasing membrane fluidity, and genes involved in cell defense mechanisms. The majority of CAZy and NCyc genes were overrepresented in permafrost soils relative to active-layer soils in both localities, with genes involved in the degradation of carbon substrates and in the degradation of N compounds indicating high microbial activity in permafrost in response to climate warming. CONCLUSIONS Our study on the functional characteristics of permafrost microbiomes underlines the remarkably high functional gene diversity of the High Arctic and temperate mountain permafrost, including a broad range of C- and N-cycling genes, and multiple survival and energetic metabolisms. Their metabolic versatility in using organic materials from ancient soils undergoing microbial degradation determine organic matter decomposition and greenhouse gas emissions upon permafrost thawing. Attention to their functional genes is therefore essential to predict potential soil-climate feedbacks to the future warmer climate.
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Affiliation(s)
- Ciro Sannino
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Weihong Qi
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
- Swiss Institute of Bioinformatics SIB, Geneva, Switzerland
| | - Joel Rüthi
- Rhizosphere Processes Group, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Beat Stierli
- Rhizosphere Processes Group, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Beat Frey
- Rhizosphere Processes Group, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland.
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Shi Y, Yuan Y, Feng Y, Zhang Y, Fan Y. Bacterial Diversity Analysis and Screening for ACC Deaminase-Producing Strains in Moss-Covered Soil at Different Altitudes in Tianshan Mountains-A Case Study of Glacier No. 1. Microorganisms 2023; 11:1521. [PMID: 37375023 DOI: 10.3390/microorganisms11061521] [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: 05/09/2023] [Revised: 06/02/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
The elevation of the snowline of the No. 1 Glacier in the Tianshan Mountains is increasing due to global warming, which has created favorable conditions for moss invasion and offers an opportunity to investigate the synergistic effects of incipient succession by mosses, plants, and soils. In this study, the concept of altitude distance was used instead of succession time. To investigate the changes of bacterial-community diversity in moss-covered soils during glacial degeneration, the relationship between bacterial community structure and environmental factors was analyzed and valuable microorganisms in moss-covered soils were explored. To do so, the determination of soil physicochemical properties, high-throughput sequencing, the screening of ACC-deaminase-producing bacteria, and the determination of ACC-deaminase activity of strains were performed on five moss-covered soils at different elevations. The results showed that the soil total potassium content, soil available phosphorus content, soil available potassium content, and soil organic-matter content of the AY3550 sample belt were significantly different compared with those of other sample belts (p < 0.05). Secondly, there was a significant difference (p < 0.05) in the ACE index or Chao1 index between the moss-covered-soil AY3550 sample-belt and the AY3750 sample-belt bacterial communities as the succession progressed. The results of PCA analysis, RDA analysis, and cluster analysis at the genus level showed that the community structure of the AY3550 sample belt and the other four sample belts differed greatly and could be divided into two successional stages. The enzyme activities of the 33 ACC-deaminase-producing bacteria isolated and purified from moss-covered soil at different altitudes ranged from 0.067 to 4.7375 U/mg, with strains DY1-3, DY1-4, and EY2-5 having the highest enzyme activities. All three strains were identified as Pseudomonas by morphology, physiology, biochemistry, and molecular biology. This study provides a basis for the changes in moss-covered soil microhabitats during glacial degradation under the synergistic effects of moss, soil, and microbial communities, as well as a theoretical basis for the excavation of valuable microorganisms under glacial moss-covered soils.
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Affiliation(s)
- Yanlei Shi
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science & Technology, Xinjiang University, Urumqi 830046, China
| | - Ye Yuan
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science & Technology, Xinjiang University, Urumqi 830046, China
| | - Yingying Feng
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science & Technology, Xinjiang University, Urumqi 830046, China
| | - Yinghao Zhang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science & Technology, Xinjiang University, Urumqi 830046, China
| | - Yonghong Fan
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science & Technology, Xinjiang University, Urumqi 830046, China
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10
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Wang Y, Guo Y, Wang X, Song C, Song Y, Liu Z, Wang S, Gao S, Ma G. Mineral protection controls soil organic carbon stability in permafrost wetlands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161864. [PMID: 36720397 DOI: 10.1016/j.scitotenv.2023.161864] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
Mineral protection can slow the effect of warming on the mineralization of organic carbon (OC) in permafrost wetlands, which has an important impact on the dynamics of soil OC. However, the response mechanisms of wetland mineral soil to warming in permafrost areas are unclear. In this study, the soil of the southern edge of the Eurasian permafrost area was selected, and bulk and heavy fraction (HF) soil was subjected to indoor warming incubation experiments using physical fractionation. The results showed that the HF accounted for 51.25 % of the total OC mineralization in the bulk soil, and the δ13C value of the CO2 that was emitted in the HF soil was higher than that of the bulk soil. This indicates the potential availability of mineral soil and that the mineralized OC in the HF was the more stable component. Additionally, the mineralization of the mineral subsoil after warming by 10 °C was only about half of the increase in the organic topsoil, and the temperature sensitivity was significantly negatively correlated with the Fe/Al oxides to OC ratio. The results indicate that under conditions of permafrost degradation, the physical protection of mineral soil at high latitudes is essential for the stability of OC, which may slow the trend of permafrost wetlands becoming carbon sources.
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Affiliation(s)
- Yao Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yuedong Guo
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China.
| | - Xianwei Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China
| | - Changchun Song
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China; School of Hydraulic Engineering, Dalian University of Technology, Dalian 116023, China
| | - Yanyu Song
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China
| | - Zhendi Liu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China
| | - Shujie Wang
- Northeast Forestry University, Harbin 150000, China
| | - Siqi Gao
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Guobao Ma
- Northeast Forestry University, Harbin 150000, China
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11
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Guo W, Zhang J, Li MH, Qi L. Soil fungal community characteristics vary with bamboo varieties and soil compartments. Front Microbiol 2023; 14:1120679. [PMID: 36814565 PMCID: PMC9939831 DOI: 10.3389/fmicb.2023.1120679] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 01/16/2023] [Indexed: 02/09/2023] Open
Abstract
Soil fungi play an important role in nutrient cycling, mycorrhizal symbiosis, antagonism against pathogens, and organic matter decomposition. However, our knowledge about the community characteristics of soil fungi in relation to bamboo varieties is still limited. Here, we compared the fungal communities in different soil compartments (rhizosphere vs. bulk soil) of moso bamboo (Phyllostachys edulis) and its four varieties using ITS high-throughput sequencing technology. The fungal α diversity (Shannon index) in bulk soil was significantly higher than that in rhizosphere soil, but it was not affected by bamboo variety or interactions between the soil compartment and bamboo variety. Soil compartment and bamboo variety together explained 31.74% of the variation in fungal community diversity. Soil compartment and bamboo variety were the key factors affecting the relative abundance of the major fungal taxa at the phylum and genus levels. Soil compartment mainly affected the relative abundance of the dominant fungal phylum, while bamboo variety primarily influenced the dominant fungal genus. Network analysis showed that the fungal network in rhizosphere soil was more complex, stable, and connected than that in bulk soil. A FUNGuild database analysis indicated that both soil compartment and bamboo variety affect fungal functions. Our findings provide new insights into the roles of both soil compartments and plant species (including variety) in shaping soil fungal communities.
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Affiliation(s)
- Wen Guo
- Key Laboratory of National Forestry and Grassland Administration/Beijing Bamboo and Rattan Science and Technology, International Centre for Bamboo and Rattan, Beijing, China,Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Jian Zhang
- Key Laboratory of National Forestry and Grassland Administration/Beijing Bamboo and Rattan Science and Technology, International Centre for Bamboo and Rattan, Beijing, China
| | - Mai-He Li
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland,Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China,School of Life Science, Hebei University, Baoding, China,*Correspondence: Mai-He Li,
| | - Lianghua Qi
- Key Laboratory of National Forestry and Grassland Administration/Beijing Bamboo and Rattan Science and Technology, International Centre for Bamboo and Rattan, Beijing, China,Sanya Research Base, International Centre for Bamboo and Rattan, Sanya, China,Lianghua Qi,
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12
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The metamicrobiome: key determinant of the homeostasis of nutrient recycling. Trends Ecol Evol 2023; 38:183-195. [PMID: 36328807 DOI: 10.1016/j.tree.2022.10.003] [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: 06/27/2022] [Revised: 10/05/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022]
Abstract
The metamicrobiome is an integrated concept to study carbon and nutrient recycling in ecosystems. Decomposition of plant-derived matter by free-living microbes and fire - two key recycling pathways - are highly sensitive to global change. Mutualistic associations of microbes with plants and animals strongly reduce this sensitivity. By solving a fundamental allometric trade-off between metabolic and homeostatic capacity, these mutualisms enable continued recycling of plant matter where and when conditions are unfavourable for the free-living microbiome. A diverse metamicrobiome - where multiple plant- and animal-associated microbiomes complement the free-living microbiome - thus enhances homeostasis of ecosystem recycling rates in variable environments. Research into metamicrobiome structure and functioning in ecosystems is therefore important for progress towards understanding environmental change.
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13
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Permafrost in the Cretaceous supergreenhouse. Nat Commun 2022; 13:7946. [PMID: 36572668 PMCID: PMC9792593 DOI: 10.1038/s41467-022-35676-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 12/19/2022] [Indexed: 12/27/2022] Open
Abstract
Earth's climate during the last 4.6 billion years has changed repeatedly between cold (icehouse) and warm (greenhouse) conditions. The hottest conditions (supergreenhouse) are widely assumed to have lacked an active cryosphere. Here we show that during the archetypal supergreenhouse Cretaceous Earth, an active cryosphere with permafrost existed in Chinese plateau deserts (astrochonological age ca. 132.49-132.17 Ma), and that a modern analogue for these plateau cryospheric conditions is the aeolian-permafrost system we report from the Qiongkuai Lebashi Lake area, Xinjiang Uygur Autonomous Region, China. Significantly, Cretaceous plateau permafrost was coeval with largely marine cryospheric indicators in the Arctic and Australia, indicating a strong coupling of the ocean-atmosphere system. The Cretaceous permafrost contained a rich microbiome at subtropical palaeolatitude and 3-4 km palaeoaltitude, analogous to recent permafrost in the western Himalayas. A mindset of persistent ice-free greenhouse conditions during the Cretaceous has stifled consideration of permafrost thaw as a contributor of C and nutrients to the palaeo-oceans and palaeo-atmosphere.
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14
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Parada-Pozo G, Bravo LA, Sáez PL, Cavieres LA, Reyes-Díaz M, Abades S, Alfaro FD, De la Iglesia R, Trefault N. Vegetation drives the response of the active fraction of the rhizosphere microbial communities to soil warming in Antarctic vascular plants. FEMS Microbiol Ecol 2022; 98:6679102. [PMID: 36040342 DOI: 10.1093/femsec/fiac099] [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: 03/02/2022] [Revised: 08/11/2022] [Accepted: 08/27/2022] [Indexed: 01/21/2023] Open
Abstract
In the Antarctic Peninsula, increases in mean annual temperature are associated with the coverage and population density of the two Antarctic vascular plant species-Deschampsia antarctica and Colobanthus quitensis-potentially modifying critical soil processes. In this study, we characterized the diversity and community composition of active microorganisms inhabiting the vascular plant rhizosphere in two sites with contrasting vegetation cover in King George Island, Western Antarctic Peninsula. We assessed the interplay between soil physicochemical properties and microbial diversity and composition, evaluating the effect of an in situ experimental warming on the microbial communities of the rhizosphere from D. antarctica and C. quitensis. Bacteria and Eukarya showed different responses to warming in both sites, and the effect was more noticeable in microbial eukaryotes from the low vegetation site. Furthermore, important changes were found in the relative abundance of Tepidisphaerales (Bacteria) and Ciliophora (Eukarya) between warming and control treatments. Our results showed that rhizosphere eukaryal communities are more sensitive to in situ warming than bacterial communities. Overall, our results indicate that vegetation drives the response of the active fraction of the microbial communities from the rhizosphere of Antarctic vascular plants to soil warming.
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Affiliation(s)
- Génesis Parada-Pozo
- Centro GEMA-Genómica, Ecología & Medio Ambiente, Facultad de Ciencias, Universidad Mayor, 8580745, Santiago, Chile
| | - León A Bravo
- Departamento de Ciencias Agronómicas y Recursos Naturales, Facultad de Ciencias Agropecuarias y Medioambiente, Universidad de la Frontera. 4811230, Temuco, Chile
| | - Patricia L Sáez
- Laboratorio Cultivo de Tejidos Vegetales, Centro de Biotecnología, Departamento de Silvicultura, Facultad de Ciencias Forestales, Universidad de Concepción, Concepción, 4070386, Chile.,Instituto de Ecología y Biodiversidad (IEB), 775000, Santiago, Chile
| | - Lohengrin A Cavieres
- Instituto de Ecología y Biodiversidad (IEB), 775000, Santiago, Chile.,Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, 4070386, Chile
| | - Marjorie Reyes-Díaz
- Departamento de Ciencias Químicas y Recursos Naturales, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, Temuco, 4811230, Chile.,Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Temuco, 4811230, Chile
| | - Sebastián Abades
- Centro GEMA-Genómica, Ecología & Medio Ambiente, Facultad de Ciencias, Universidad Mayor, 8580745, Santiago, Chile
| | - Fernando D Alfaro
- Centro GEMA-Genómica, Ecología & Medio Ambiente, Facultad de Ciencias, Universidad Mayor, 8580745, Santiago, Chile
| | - Rodrigo De la Iglesia
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, 8320000, Chile
| | - Nicole Trefault
- Centro GEMA-Genómica, Ecología & Medio Ambiente, Facultad de Ciencias, Universidad Mayor, 8580745, Santiago, Chile
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15
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Sannino C, Cannone N, D'Alò F, Franzetti A, Gandolfi I, Pittino F, Turchetti B, Mezzasoma A, Zucconi L, Buzzini P, Guglielmin M, Onofri S. Fungal communities in European alpine soils are not affected by short-term in situ simulated warming than bacterial communities. Environ Microbiol 2022; 24:4178-4192. [PMID: 35691701 DOI: 10.1111/1462-2920.16090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/31/2022] [Indexed: 11/27/2022]
Abstract
The impact of global warming on biological communities colonizing European alpine ecosystems was recently studied. Hexagonal open top chambers (OTCs) were used for simulating a short-term in situ warming (estimated around 1°C) in some alpine soils to predict the impact of ongoing climate change on resident microbial communities. Total microbial DNA was extracted from soils collected either inside or outside the OTCs over 3 years of study. Bacterial and fungal rRNA copies were quantified by qPCR. Metabarcoding sequencing of taxonomy target genes was performed (Illumina MiSeq) and processed by bioinformatic tools. Alpha- and beta-diversity were used to evaluate the structure of bacterial and fungal communities. qPCR suggests that, although fluctuations have been observed between soils collected either inside and outside the OTCs, the simulated warming induced a significant (p < 0.05) shift only for bacterial abundance. Likewise, significant (p < 0.05) changes in bacterial community structure were detected in soils collected inside the OTCs, with a clear increase of oligotrophic taxa. On the contrary, fungal diversity of soils collected either inside and outside the OTCs did not exhibit significant (p < 0.05) differences, suggesting that the temperature increase in OTCs compared to ambient conditions was not sufficient to change fungal communities.
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Affiliation(s)
- Ciro Sannino
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Nicoletta Cannone
- Department of Theoretical and Applied Sciences, Insubria University, Varese, Italy
| | - Federica D'Alò
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy
| | - Andrea Franzetti
- Department of Earth and Environmental Sciences (DISAT), University of Milano-Bicocca, Milan, Italy
| | - Isabella Gandolfi
- Department of Earth and Environmental Sciences (DISAT), University of Milano-Bicocca, Milan, Italy
| | - Francesca Pittino
- Department of Earth and Environmental Sciences (DISAT), University of Milano-Bicocca, Milan, Italy
| | - Benedetta Turchetti
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Ambra Mezzasoma
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Laura Zucconi
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy
| | - Pietro Buzzini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Mauro Guglielmin
- Department of Theoretical and Applied Sciences, Insubria University, Varese, Italy
| | - Silvano Onofri
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy
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16
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Scheel M, Zervas A, Jacobsen CS, Christensen TR. Microbial Community Changes in 26,500-Year-Old Thawing Permafrost. Front Microbiol 2022; 13:787146. [PMID: 35401488 PMCID: PMC8988141 DOI: 10.3389/fmicb.2022.787146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/09/2022] [Indexed: 12/02/2022] Open
Abstract
Northern permafrost soils store more than half of the global soil carbon. Frozen for at least two consecutive years, but often for millennia, permafrost temperatures have increased drastically in the last decades. The resulting thermal erosion leads not only to gradual thaw, resulting in an increase of seasonally thawing soil thickness, but also to abrupt thaw events, such as sudden collapses of the soil surface. These could affect 20% of the permafrost zone and half of its organic carbon, increasing accessibility for deeper rooting vegetation and microbial decomposition into greenhouse gases. Knowledge gaps include the impact of permafrost thaw on the soil microfauna as well as key taxa to change the microbial mineralization of ancient permafrost carbon stocks during erosion. Here, we present the first sequencing study of an abrupt permafrost erosion microbiome in Northeast Greenland, where a thermal erosion gully collapsed in the summer of 2018, leading to the thawing of 26,500-year-old permafrost material. We investigated which soil parameters (pH, soil carbon content, age and moisture, organic and mineral horizons, and permafrost layers) most significantly drove changes of taxonomic diversity and the abundance of soil microorganisms in two consecutive years of intense erosion. Sequencing of the prokaryotic 16S rRNA and fungal ITS2 gene regions at finely scaled depth increments revealed decreasing alpha diversity with depth, soil age, and pH. The most significant drivers of variation were found in the soil age, horizons, and permafrost layer for prokaryotic and fungal beta diversity. Permafrost was mainly dominated by Proteobacteria and Firmicutes, with Polaromonas identified as the most abundant taxon. Thawed permafrost samples indicated increased abundance of several copiotrophic phyla, such as Bacteroidia, suggesting alterations of carbon utilization pathways within eroding permafrost.
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Affiliation(s)
- Maria Scheel
- Department of Ecoscience, Arctic Research Centre, Aarhus University, Roskilde, Denmark
| | - Athanasios Zervas
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | | | - Torben R. Christensen
- Department of Ecoscience, Arctic Research Centre, Aarhus University, Roskilde, Denmark
- Oulanka Research Station, Oulu University, Oulu, Finland
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