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Wu S, Fu W, Rillig MC, Chen B, Zhu YG, Huang L. Soil organic matter dynamics mediated by arbuscular mycorrhizal fungi - an updated conceptual framework. THE NEW PHYTOLOGIST 2024; 242:1417-1425. [PMID: 37529867 DOI: 10.1111/nph.19178] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 07/13/2023] [Indexed: 08/03/2023]
Abstract
Arbuscular mycorrhizal (AM) fungi play an important role in soil organic matter (SOM) formation and stabilization. Previous studies have emphasized organic compounds produced by AM fungi as persistent binding agents for aggregate formation and SOM storage. This concept overlooks the multiple biogeochemical processes mediated by AM fungal activities, which drive SOM generation, reprocessing, reorganization, and stabilization. Here, we propose an updated conceptual framework to facilitate a mechanistic understanding of the role of AM fungi in SOM dynamics. In this framework, four pathways for AM fungi-mediated SOM dynamics are included: 'Generating', AM fungal exudates and biomass serve as key sources of SOM chemodiversity; 'Reprocessing', hyphosphere microorganisms drive SOM decomposition and resynthesis; 'Reorganizing', AM fungi mediate soil physical changes and influence SOM transport, redistribution, transformation, and storage; and 'Stabilizing', AM fungi drive mineral weathering and organo-mineral interactions for SOM stabilization. Moreover, we discuss the AM fungal role in SOM dynamics at different scales, especially when translating results from small scales to complex larger scales. We believe that working with this conceptual framework can allow a better understanding of AM fungal role in SOM dynamics, therefore facilitating the development of mycorrhiza-based technologies toward soil health and global change mitigation.
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Affiliation(s)
- Songlin Wu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
- Centre for Mined Land Rehabilitation, Sustainable Minerals Institute, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Wei Fu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Matthias C Rillig
- Institute of Biology, Freie Universität Berlin, Berlin, 14195, Germany
| | - Baodong Chen
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yong-Guan Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Longbin Huang
- Centre for Mined Land Rehabilitation, Sustainable Minerals Institute, The University of Queensland, Brisbane, Qld, 4072, Australia
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2
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Mori T. Empirical evidence challenges the effectiveness of the enzymatic stoichiometry of glucosidase and phosphatase as an indicator of microbial C vs P limitation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:170079. [PMID: 38218479 DOI: 10.1016/j.scitotenv.2024.170079] [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: 10/08/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 01/15/2024]
Abstract
The ratio of β-1,4-glucosidase (BG) to acid/alkaline phosphomonoesterase (AP) (BG:AP) is commonly employed as an indicator to assess the relative microbial limitations of carbon (C) and phosphorus (P), whereby a higher BG:AP ratio suggests stronger C limitations. This approach is based on the assumption that BG and AP can represent enzymes targeting C and P, respectively. Nevertheless, it is crucial to recognize that microbial C and P acquisition involves the participation of other enzymes alongside BG and AP, and thus, the capacity of BG and AP to accurately and comprehensively represent the entire spectrum of C and P acquisition is questionable. Here, analyzing previously published data, I present a piece of empirical evidence that challenges the suitability of the BG:AP ratio as an accurate indicator of microbial limitations concerning C vs P. P fertilization decreased BG:AP in up to 27 % out of the total 109 observations, which represents a clear contradiction, as this outcome is interpreted by the enzymatic stoichiometry approach as indicating an intensified P limitation arising from P fertilization. Furthermore, the effect of P fertilization on the BG:AP ratio did not show significant differences between experimental sites characterized by higher BG:AP ratios (indicative of lesser P limitation) and those with lower BG:AP ratios (indicative of greater P limitation). Consequently, I conclude that the BG:AP ratio inadequately reflects microbial C vs P limitations.
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Affiliation(s)
- Taiki Mori
- Kyushu Research Center, Forestry and Forest Products Research Institute, FFPRI, Kurokami 4-11-16, Kumamoto 860-0862, Japan.
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3
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Yang Y, Cheng Y, Bai T, Liu S, Du Q, Xia W, Liu Y, Wang X, Chen X. Optimizing Trilobatin Production via Screening and Modification of Glycosyltransferases. Molecules 2024; 29:643. [PMID: 38338387 PMCID: PMC10856287 DOI: 10.3390/molecules29030643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 01/26/2024] [Accepted: 01/26/2024] [Indexed: 02/12/2024] Open
Abstract
Trilobatin (TBL) is a key sweet compound from the traditional Chinese sweet tea plant (Rubus suavissimus S. Lee). Because of its intense sweetness, superior taste profile, and minimal caloric value, it serves as an exemplary natural dihydrochalcone sweetener. It also has various health benefits, including anti-inflammatory and glucose-lowering effects. It is primarily produced through botanical extraction, which impedes its scalability and cost-effectiveness. In a novel biotechnological approach, phloretin is used as a precursor that is transformed into TBL by the glycosyltransferase enzyme ph-4'-OGT. However, this enzyme's low catalytic efficiency and by-product formation limit the large-scale synthesis of TBL. In our study, the enzyme Mdph-4'-OGT was used to screen 17 sequences across species for TBL synthesis, of which seven exhibited catalytic activity. Notably, PT577 exhibited an unparalleled 97.3% conversion yield within 3 h. We then optimized the reaction conditions of PT577, attaining a peak TBL bioproduction of 163.3 mg/L. By employing virtual screening, we identified 25 mutation sites for PT577, thereby creating mutant strains that reduced by-products by up to 50%. This research enhances the enzymatic precision for TBL biosynthesis and offers a robust foundation for its industrial-scale production, with broader implications for the engineering and in silico analysis of glycosyltransferases.
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Affiliation(s)
- Yue Yang
- Jiaxing Synbiolab Biotechnology Co., Ltd., Jiaxing 314006, China; (Y.Y.); (T.B.); (S.L.); (Q.D.)
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China; (Y.C.); (W.X.); (Y.L.)
| | - Yuhan Cheng
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China; (Y.C.); (W.X.); (Y.L.)
| | - Tao Bai
- Jiaxing Synbiolab Biotechnology Co., Ltd., Jiaxing 314006, China; (Y.Y.); (T.B.); (S.L.); (Q.D.)
| | - Shimeng Liu
- Jiaxing Synbiolab Biotechnology Co., Ltd., Jiaxing 314006, China; (Y.Y.); (T.B.); (S.L.); (Q.D.)
| | - Qiuhui Du
- Jiaxing Synbiolab Biotechnology Co., Ltd., Jiaxing 314006, China; (Y.Y.); (T.B.); (S.L.); (Q.D.)
| | - Wenhao Xia
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China; (Y.C.); (W.X.); (Y.L.)
| | - Yi Liu
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China; (Y.C.); (W.X.); (Y.L.)
| | - Xiao Wang
- Jiaxing Synbiolab Biotechnology Co., Ltd., Jiaxing 314006, China; (Y.Y.); (T.B.); (S.L.); (Q.D.)
| | - Xianqing Chen
- Jiaxing Synbiolab Biotechnology Co., Ltd., Jiaxing 314006, China; (Y.Y.); (T.B.); (S.L.); (Q.D.)
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Luo H, Wang C, Zhang K, Ming L, Chu H, Wang H. Elevational changes in soil properties shaping fungal community assemblages in terrestrial forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165840. [PMID: 37516167 DOI: 10.1016/j.scitotenv.2023.165840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 07/13/2023] [Accepted: 07/25/2023] [Indexed: 07/31/2023]
Abstract
Environmental variables shifted by climate change act as driving factors in determining plant-associated microbial communities in terrestrial ecosystems. However, how elevation-induced changes in soil properties shape the microbial community in forest ecosystems remains less understood. Thus, the Pinus tabuliformis forests at elevations of 1500 m, 1900 m, and 2300 m above sea level were investigated to explore the effect of environmental factors on microbial assemblage. Significant changes in the soil physicochemical properties were found across the investigated elevations, such as soil moisture, temperature, pH, nitrogen (N), and phosphorus (P). Soil enzymatic activities, including soil sucrase, phosphatase, and dehydrogenase, were significantly affected by elevation, and sucrase showed a linear correlation with soil organic matter. Furthermore, the richness of fungal communities in the rhizosphere was decreased as elevation increased, while a humpback pattern was found for roots. Certain core microbiota members, such as Agaricomycetes, Leotiomycetes, and Pezizomycetes, were crucial in maintaining a stable ecological niche in both the root and rhizosphere. We also found that shifting of fungal communities in the rhizosphere were more related to physical properties (e.g., pH, soil moisture, and soil temperature), while changes in root fungal communities along elevation gradient were related mostly to soil nutrients (e.g., soil N and P). Overall, this study demonstrates that the assemblage of the root and rhizosphere fungal communities in P. tabuliformis forest primarily depends on elevation-induced changes in environmental variables and highlights the importance of predicting fungal responses to future climate change.
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Affiliation(s)
- Huan Luo
- College of Forestry, Northwest A&F University, Yangling, China; Department of Applied Biology, Chungnam National University, Daejeon, South Korea
| | - Chunyan Wang
- College of Forestry, Northwest A&F University, Yangling, China
| | - Kaile Zhang
- North Florida Research and Education Center, University of Florida, 155 Research Road, Quincy, FL, USA
| | - Li Ming
- College of Forestry, Northwest A&F University, Yangling, China; China University of Mining and Technology, School of Mechanics and Civil Engineering, China
| | - Honglong Chu
- College of Forestry, Northwest A&F University, Yangling, China; College of Biological Resource and Food Engineering, Center for Yunnan Plateau Biological Resources Protection and Utilization, Qujing Normal University, Qujing, China
| | - Haihua Wang
- College of Forestry, Northwest A&F University, Yangling, China; North Florida Research and Education Center, University of Florida, 155 Research Road, Quincy, FL, USA.
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Preparation, characteristics, and soil-biodegradable analysis of corn starch/nanofibrillated cellulose (CS/NFC) and corn starch/nanofibrillated lignocellulose (CS/NFLC) films. Carbohydr Polym 2023; 309:120699. [PMID: 36906356 DOI: 10.1016/j.carbpol.2023.120699] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/26/2023] [Accepted: 02/11/2023] [Indexed: 02/17/2023]
Abstract
The objective of this study was to produce high-performance and biodegradable starch nanocomposites through film casting by using corn starch/nanofibrillated cellulose (CS/NFC) and corn starch/nanofibrillated lignocellulose (CS/NFLC). NFC and NFLC were obtained by super grinding process and added to fibrogenic solutions (1, 3, and 5 g/100 g of starch). The addition of NFC and NFLC from 1 to 5 % was verified to be influential in enhancing mechanical properties (tensile, burst, and tear index) and reducing WVTR, air permeability, and essential properties in food packaging materials. But, in comparison to control samples, the addition of NFC and NFLC from 1 to 5 % decreased the opacity, transparency, and tear index of films. In acidic solutions, produced films were more soluble than in alkaline or water solutions. The soil-biodegradability analysis showed that after 30 days of exposure to soil, the control film lost 79.5 % of its weight. The weight loss of all films was >81 % after 40 days. The results of this study may contribute to expanding the industrial applications of both NFC and NFLC by laying a basis for preparing high-performance CS/NFC or CS/NFLC.
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Tveit AT, Söllinger A, Rainer EM, Didriksen A, Hestnes AG, Motleleng L, Hellinger HJ, Rattei T, Svenning MM. Thermal acclimation of methanotrophs from the genus Methylobacter. THE ISME JOURNAL 2023; 17:502-513. [PMID: 36650275 PMCID: PMC10030640 DOI: 10.1038/s41396-023-01363-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 01/19/2023]
Abstract
Methanotrophs oxidize most of the methane (CH4) produced in natural and anthropogenic ecosystems. Often living close to soil surfaces, these microorganisms must frequently adjust to temperature change. While many environmental studies have addressed temperature effects on CH4 oxidation and methanotrophic communities, there is little knowledge about the physiological adjustments that underlie these effects. We have studied thermal acclimation in Methylobacter, a widespread, abundant, and environmentally important methanotrophic genus. Comparisons of growth and CH4 oxidation kinetics at different temperatures in three members of the genus demonstrate that temperature has a strong influence on how much CH4 is consumed to support growth at different CH4 concentrations. However, the temperature effect varies considerably between species, suggesting that how a methanotrophic community is composed influences the temperature effect on CH4 uptake. To understand thermal acclimation mechanisms widely we carried out a transcriptomics experiment with Methylobacter tundripaludum SV96T. We observed, at different temperatures, how varying abundances of transcripts for glycogen and protein biosynthesis relate to cellular glycogen and ribosome concentrations. Our data also demonstrated transcriptional adjustment of CH4 oxidation, oxidative phosphorylation, membrane fatty acid saturation, cell wall composition, and exopolysaccharides between temperatures. In addition, we observed differences in M. tundripaludum SV96T cell sizes at different temperatures. We conclude that thermal acclimation in Methylobacter results from transcriptional adjustment of central metabolism, protein biosynthesis, cell walls and storage. Acclimation leads to large shifts in CH4 consumption and growth efficiency, but with major differences between species. Thus, our study demonstrates that physiological adjustments to temperature change can substantially influence environmental CH4 uptake rates and that consideration of methanotroph physiology might be vital for accurate predictions of warming effects on CH4 emissions.
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Affiliation(s)
- Alexander T Tveit
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway.
| | - Andrea Söllinger
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Edda Marie Rainer
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Alena Didriksen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Anne Grethe Hestnes
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Liabo Motleleng
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Hans-Jörg Hellinger
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Vienna, Austria
- University of Vienna, Doctoral School in Microbiology and Environmental Science, Vienna, Austria
| | - Thomas Rattei
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Vienna, Austria
| | - Mette M Svenning
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
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7
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Rusterholz HP, Huber K, Baur B. Invasion of a Horticultural Plant into Forests: Lamium galeobdolon argentatum Affects Native Above-Ground Vegetation and Soil Properties. PLANTS (BASEL, SWITZERLAND) 2023; 12:1527. [PMID: 37050152 PMCID: PMC10097399 DOI: 10.3390/plants12071527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 06/19/2023]
Abstract
Horticultural trade is considered the most important pathway for the introduction of non-native plant species. Numerous horticultural plants are spreading from private gardens and public green space into natural habitats and have the potential to alter native biodiversity and ecosystem functioning. We assessed the invasiveness of the horticultural plant Lamium galeobdolon subsp. argentatum. We documented its spread in semi-natural habitats in the surroundings of Basel, Switzerland, over the past decades. We compared the performance of L. g. argentatum with that of the native subspecies Lamium galeobdolon galeobdolon based on surveys in forests and a pot experiment under standardized conditions. We also assessed whether the two subspecies differentially affect native forest vegetation and various physical, chemical and biological soil properties. The horticultural L. g. argentatum has tripled its occurrence in forests in the region of Basel in the last four decades. Lamium g. argentatum had both a higher growth rate and regeneration capacity than the native subspecies. Furthermore, L. g. argentatum reduced native plant species richness and changed the species composition of the ground vegetation, in addition to altering several soil properties in deciduous forests. Lamium g. argentatum should therefore be considered an invasive taxon.
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Affiliation(s)
- Hans-Peter Rusterholz
- Department of Environmental Sciences, University of Basel, Bernoullistrasse 30, 4056 Basel, Switzerland; (H.-P.R.); (K.H.)
| | - Katharina Huber
- Department of Environmental Sciences, University of Basel, Bernoullistrasse 30, 4056 Basel, Switzerland; (H.-P.R.); (K.H.)
- Program Man-Society-Environment, Department of Environmental Sciences, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Bruno Baur
- Department of Environmental Sciences, University of Basel, Bernoullistrasse 30, 4056 Basel, Switzerland; (H.-P.R.); (K.H.)
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Liu L, Chen H, He Y, Liu J, Dan X, Jiang L, Zhan W. Carbon stock stability in drained peatland after simulated plant carbon addition: Strong dependence on deeper soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 848:157539. [PMID: 35908690 DOI: 10.1016/j.scitotenv.2022.157539] [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: 05/29/2022] [Revised: 07/10/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
Peatlands are vital soil carbon sinks, yet this function is jeopardized by plant carbon which could change the decomposition rate of soil organic carbon, knowing as "priming effect". How the priming effect depends on depth is a critical question in drained peatland given the heterogeneity of soil layers defined by the water table, which include the surface acrotelm, inter-mesotelm and deep catotelm. Here, through incubation, we quantified the response of these three soil layers to addition of 13C-labeled oxalate, glucose, cellulose, or cinnamic acid under anoxic or oxic conditions on the Zoige Plateau in Tibet. Soil carbon in the inter-mesotelm showed the greatest decomposition, with the highest humification index and lowest microbial biomass carbon, while the soil carbon at the surface acrotelm was least decomposed. Under anoxic conditions, exogenous carbon addition reduced CO2 emission by 12.2% at the surface acrotelm but increased by 59.8% in the inter-mesotelm and 23.5% in the deep catotelm. In the inter-mesotelm, oxalate addition significantly increased CO2 emission by 63.9%, while cinnamic acid significantly increased it by 92.9%. In the deep catotelm, cinnamic acid significantly increased CO2 emission by 55.3%. These results suggested that deeper soil organic carbon was more sensitive to plant carbon, particularly complex or recalcitrant carbon, than surface acrotelm soil. Under oxic conditions, carbon addition increased surface soil CO2 emission by 18.9%, and triggered even greater increase at inter-mesotelm and deep catotelm soil, with proportions of 48.3% and 32.0%, respectively. Under both conditions, peat profile CO2 release increased by 17.2-31.4% after exogenous carbon addition, and more than 77.8% of the increase came from the deeper two layers. These findings highlighted the need to take full account of priming effect of deeper soil in order to assess and predict the stability of carbon stocks in drained peatland.
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Affiliation(s)
- Liangfeng Liu
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of, Biology, Chinese Academy of Sciences, Chengdu 610041, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China
| | - Huai Chen
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of, Biology, Chinese Academy of Sciences, Chengdu 610041, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China.
| | - Yixin He
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of, Biology, Chinese Academy of Sciences, Chengdu 610041, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China.
| | - Jianliang Liu
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of, Biology, Chinese Academy of Sciences, Chengdu 610041, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China
| | - Xue Dan
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of, Biology, Chinese Academy of Sciences, Chengdu 610041, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China
| | - Lin Jiang
- Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China; Institute of Environment and Ecology, Shandong Normal University, Ji'nan, Shandong 250358, China
| | - Wei Zhan
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of, Biology, Chinese Academy of Sciences, Chengdu 610041, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China
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Wu Y, Zhou H, Sun W, Zhao Q, Liang M, Chen W, Guo Z, Jiang Y, Jiang Y, Liu G, Xue S. Temperature sensitivity of soil enzyme kinetics under N and P fertilization in an alpine grassland, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156042. [PMID: 35597335 DOI: 10.1016/j.scitotenv.2022.156042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/14/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
Soil nutrient cycling can be best studied by supplementing the soil with N and P fertilizers. Soil enzyme kinetic parameters (Vmax and Km) can be used to reflect the maximum reaction rates and affinities of soil enzymes. However, how N and P fertilizers affect the temperature sensitivity of soil enzyme kinetics is poorly understood. Therefore, our study investigated the response of soil enzyme kinetic temperature sensitivity relevant to C, N, and P cycles based on a 9-year fertilization (N and P) experiment performed in an alpine grassland on the Qinghai-Tibetan Plateau in China. Our results showed the following: N and P addition positively affected the Km of β-glucosidase (BG); P and NP interaction significantly increased the Km of phosphatase (AP), indicating that N and P addition significantly negatively affected the substrate affinity of soil enzymes. The temperature sensitivity of Michaelis-Menten kinetics was different for different enzymes. N and P fertilization decreased the temperature sensitivity of Km of BG but increased the temperature sensitivity of the Km of N-acetyl-glucosaminidase (NAG) and AP. In our study, P and NP fertilization increased the temperature sensitivity and activation energy of the Vmax of BG, indicating that P elements promoted the secretion of more extracellular enzymes by soil microbes to cope with temperature changes. The enzymes involved in the soil N and P cycle responded to the exogenous N and P through increases and decreases in the temperature sensitivity of the Km and Vmax, respectively. This study is crucial for investigating the impact of nutrient input on soil ecosystem functions under future climate warming conditions.
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Affiliation(s)
- Yang Wu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - HuaKun Zhou
- Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Regions, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810000, PR China; State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810000, PR China
| | - Wei Sun
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - QiFan Zhao
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - Meng Liang
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - WenJing Chen
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - ZiQi Guo
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - YaoKun Jiang
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry Water Resources, Yangling 712100, PR China
| | - Yue Jiang
- College of Economics & Management, Northwest A&F University, Yangling 712100, PR China
| | - GuoBin Liu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry Water Resources, Yangling 712100, PR China
| | - Sha Xue
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry Water Resources, Yangling 712100, PR China.
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10
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Alves RJE, Callejas IA, Marschmann GL, Mooshammer M, Singh HW, Whitney B, Torn MS, Brodie EL. Kinetic Properties of Microbial Exoenzymes Vary With Soil Depth but Have Similar Temperature Sensitivities Through the Soil Profile. Front Microbiol 2021; 12:735282. [PMID: 34917043 PMCID: PMC8669745 DOI: 10.3389/fmicb.2021.735282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/03/2021] [Indexed: 11/13/2022] Open
Abstract
Current knowledge of the mechanisms driving soil organic matter (SOM) turnover and responses to warming is mainly limited to surface soils, although over 50% of global soil carbon is contained in subsoils. Deep soils have different physicochemical properties, nutrient inputs, and microbiomes, which may harbor distinct functional traits and lead to different SOM dynamics and temperature responses. We hypothesized that kinetic and thermal properties of soil exoenzymes, which mediate SOM depolymerization, vary with soil depth, reflecting microbial adaptation to distinct substrate and temperature regimes. We determined the Michaelis-Menten (MM) kinetics of three ubiquitous enzymes involved in carbon (C), nitrogen (N) and phosphorus (P) acquisition at six soil depths down to 90 cm at a temperate forest, and their temperature sensitivity based on Arrhenius/Q10 and Macromolecular Rate Theory (MMRT) models over six temperatures between 4–50°C. Maximal enzyme velocity (Vmax) decreased strongly with depth for all enzymes, both on a dry soil mass and a microbial biomass C basis, whereas their affinities increased, indicating adaptation to lower substrate availability. Surprisingly, microbial biomass-specific catalytic efficiencies also decreased with depth, except for the P-acquiring enzyme, indicating distinct nutrient demands at depth relative to microbial abundance. These results suggested that deep soil microbiomes encode enzymes with intrinsically lower turnover and/or produce less enzymes per cell, reflecting distinct life strategies. The relative kinetics between different enzymes also varied with depth, suggesting an increase in relative P demand with depth, or that phosphatases may be involved in C acquisition. Vmax and catalytic efficiency increased consistently with temperature for all enzymes, leading to overall higher SOM-decomposition potential, but enzyme temperature sensitivity was similar at all depths and between enzymes, based on both Arrhenius/Q10 and MMRT models. In a few cases, however, temperature affected differently the kinetic properties of distinct enzymes at discrete depths, suggesting that it may alter the relative depolymerization of different compounds. We show that soil exoenzyme kinetics may reflect intrinsic traits of microbiomes adapted to distinct soil depths, although their temperature sensitivity is remarkably uniform. These results improve our understanding of critical mechanisms underlying SOM dynamics and responses to changing temperatures through the soil profile.
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Affiliation(s)
- Ricardo J Eloy Alves
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Ileana A Callejas
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.,Department of Civil and Environmental Engineering, University of California, Los Angeles, Los Angeles, CA, United States
| | - Gianna L Marschmann
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Maria Mooshammer
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, United States
| | - Hans W Singh
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Bizuayehu Whitney
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Margaret S Torn
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.,Energy and Resources Group, University of California, Berkeley, Berkeley, CA, United States
| | - Eoin L Brodie
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.,Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, United States
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11
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Zhang J, Sayer EJ, Zhou J, Li Y, Li Y, Li Z, Wang F. Long-term fertilization modifies the mineralization of soil organic matter in response to added substrate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 798:149341. [PMID: 34375236 DOI: 10.1016/j.scitotenv.2021.149341] [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: 05/09/2021] [Revised: 07/14/2021] [Accepted: 07/25/2021] [Indexed: 06/13/2023]
Abstract
The turnover of SOC in soils is strongly influenced by the availability of substrate and nutrients, especially nitrogen (N) and phosphorus (P). Here, we assessed how long-term fertilization modified SOM mineralization in response to added substrate in a tropical forest. We carried out a 90-day incubation study in which we added two structurally similar compounds which differed in microbial metabolic availability: corn cellulose or corn starch to soils collected from a long-term (11 years) factorial N and P fertilization experiment site in a tropical forest in south China. We measured total soil mineralization rate (CO2 efflux) to characterize SOM mineralization and using 13C isotope signatures to determine the source of the CO2 (original soil C or added substrate) and assessed changes in extracellular enzyme activities: acid phosphomonoesterase (AP), β-1,4-glucosidase (BG), β-1,4- N-acetaminophen glucosidase (NAG), phenol oxidase (PHO) and peroxidase (PER), and microbial biomarkers to determine whether nutrient stoichiometry and decomposer communities explain differences in SOM mineralization rates. Total C mineralization increased substantially with substrate addition, particularly cellulose (5.38, 7.13, 5.58 and 5.37 times for N, P, NP fertilization and CK, respectively) compared to no substrate addition, and original soil C mineralization was further enhanced in long-term N (3.40% and 5.18% for cellulose and starch addition, respectively) or NP (35.11% for cellulose addition) fertilized soils compared to control treatment. Enzyme activities were stimulated by the addition of both substrates but suppressed by P-fertilization. Addition of both substrates increased microbial investment in P-acquisition, but only starch addition promoted C investment in N-acquisition. Finally, fungal abundance increased with substrate addition to a greater extent than bacterial abundance, particularly in cellulose-amended soils, and the effect was amplified by long-term fertilization. Our findings indicate that SOM mineralization might be enhanced in N and P enrichment ecosystems, since the litter input can liberate microbes from C limitation and stimulate SOM mineralization if N and P are sufficient. Our study further demonstrates that structurally similar substrates can have distinct effects on SOM mineralization and the extent of SOM mineralization is strongly dependent on elemental stoichiometry, as well as the resource requirements of microbial decomposers.
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Affiliation(s)
- Jingfan Zhang
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China; University of Chinese Academy of Sciences, Beijing 100049, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Emma J Sayer
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK; Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Balboa, Ancon, Panama, Panama
| | - Jinge Zhou
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China; University of Chinese Academy of Sciences, Beijing 100049, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Yingwen Li
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China
| | - Yongxing Li
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China
| | - Zhian Li
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Faming Wang
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China.
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12
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Novoa A, Foxcroft LC, Keet JH, Pyšek P, Le Roux JJ. The invasive cactus Opuntia stricta creates fertility islands in African savannas and benefits from those created by native trees. Sci Rep 2021; 11:20748. [PMID: 34675315 PMCID: PMC8531129 DOI: 10.1038/s41598-021-99857-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 09/27/2021] [Indexed: 01/05/2023] Open
Abstract
The patchy distribution of trees typical of savannas often results in a discontinuous distribution of water, nutrient resources, and microbial communities in soil, commonly referred to as "islands of fertility". We assessed how this phenomenon may affect the establishment and impact of invasive plants, using the invasion of Opuntia stricta in South Africa's Kruger National Park as case study. We established uninvaded and O. stricta-invaded plots under the most common woody tree species in the study area (Vachellia nilotica subsp. kraussiana and Spirostachys africana) and in open patches with no tree cover. We then compared soil characteristics, diversity and composition of the soil bacterial communities, and germination performance of O. stricta and native trees between soils collected in each of the established plots. We found that the presence of native trees and invasive O. stricta increases soil water content and nutrients, and the abundance and diversity of bacterial communities, and alters soil bacterial composition. Moreover, the percentage and speed of germination of O. stricta were higher in soils conditioned by native trees compared to soils collected from open patches. Finally, while S. africana and V. nilotica trees appear to germinate equally well in invaded and uninvaded soils, O. stricta had lower and slower germination in invaded soils, suggesting the potential release of phytochemicals by O. stricta to avoid intraspecific competition. These results suggest that the presence of any tree or shrub in savanna ecosystems, regardless of origin (i.e. native or alien), can create favourable conditions for the establishment and growth of other plants.
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Affiliation(s)
- Ana Novoa
- grid.418095.10000 0001 1015 3316Department of Invasion Ecology, Institute of Botany, Czech Academy of Sciences, 252 43 Průhonice, Czech Republic ,grid.11956.3a0000 0001 2214 904XDepartment of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa ,grid.452736.10000 0001 2166 5237Invasive Species Programme, South African National Biodiversity Institute, Kirstenbosch Research Centre, Claremont, South Africa
| | - Llewellyn C. Foxcroft
- grid.11956.3a0000 0001 2214 904XDepartment of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa ,grid.463628.d0000 0000 9533 5073Scientific Services, South African National Parks, P/Bag X402, Skukuza, 1350 South Africa
| | - Jan-Hendrik Keet
- grid.11956.3a0000 0001 2214 904XDepartment of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa ,grid.11956.3a0000 0001 2214 904XDepartment of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Petr Pyšek
- grid.418095.10000 0001 1015 3316Department of Invasion Ecology, Institute of Botany, Czech Academy of Sciences, 252 43 Průhonice, Czech Republic ,grid.4491.80000 0004 1937 116XDepartment of Ecology, Faculty of Science, Charles University, Viničná 7, 128 44 Prague, Czech Republic
| | - Johannes J. Le Roux
- grid.11956.3a0000 0001 2214 904XDepartment of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa ,grid.11956.3a0000 0001 2214 904XDepartment of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa ,grid.1004.50000 0001 2158 5405Department of Biological Sciences, Macquarie University, Sydney, NSW 2109 Australia
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13
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Gioia C, Giacobazzi G, Vannini M, Totaro G, Sisti L, Colonna M, Marchese P, Celli A. End of Life of Biodegradable Plastics: Composting versus Re/Upcycling. CHEMSUSCHEM 2021; 14:4167-4175. [PMID: 34363734 PMCID: PMC8518687 DOI: 10.1002/cssc.202101226] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/04/2021] [Indexed: 05/16/2023]
Abstract
Nowadays the issues related to the end of life of traditional plastics are very urgent due to the important pollution problems that plastics have caused. Biodegradable plastics can help to try to mitigate these problems, but even bioplastics need much attention to carefully evaluate the different options for plastic waste disposal. In this Minireview, three different end-of-life scenarios (composting, recycling, and upcycling) were evaluated in terms of literature review. As a result, the ability of bioplastics to be biodegraded by composting has been related to physical variables and materials characteristics. Hence, it is possible to deduce that the process is mature enough to be a good way to minimize bioplastic waste and valorize it for the production of a fertilizer. Recycling and upcycling options, which could open up many interesting new scenarios for the production of high-value materials, are less studied. Research in this area can be strongly encouraged.
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Affiliation(s)
- Claudio Gioia
- Department of Civil, Chemical, Environmental and Materials EngineeringUniversity of BolognaVia Terracini 2840131BolognaItaly
| | - Greta Giacobazzi
- Department of Civil, Chemical, Environmental and Materials EngineeringUniversity of BolognaVia Terracini 2840131BolognaItaly
| | - Micaela Vannini
- Department of Civil, Chemical, Environmental and Materials EngineeringUniversity of BolognaVia Terracini 2840131BolognaItaly
| | - Grazia Totaro
- Department of Civil, Chemical, Environmental and Materials EngineeringUniversity of BolognaVia Terracini 2840131BolognaItaly
| | - Laura Sisti
- Department of Civil, Chemical, Environmental and Materials EngineeringUniversity of BolognaVia Terracini 2840131BolognaItaly
| | - Martino Colonna
- Department of Civil, Chemical, Environmental and Materials EngineeringUniversity of BolognaVia Terracini 2840131BolognaItaly
| | - Paola Marchese
- Department of Civil, Chemical, Environmental and Materials EngineeringUniversity of BolognaVia Terracini 2840131BolognaItaly
| | - Annamaria Celli
- Department of Civil, Chemical, Environmental and Materials EngineeringUniversity of BolognaVia Terracini 2840131BolognaItaly
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14
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The Exudation of Surplus Products Links Plant Functional Traits and Plant-Microbial Stoichiometry. LAND 2021. [DOI: 10.3390/land10080840] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The rhizosphere is a hot spot of soil microbial activity and is largely fed by root exudation. The carbon (C) exudation flux, coupled with plant growth, is considered a strategy of plants to facilitate nutrient uptake. C exudation is accompanied by a release of nutrients. Nitrogen (N) and phosphorus (P) co-limit the productivity of the plant-microbial system. Therefore, the C:N:P stoichiometry of exudates should be linked to plant nutrient economies, plant functional traits (PFT) and soil nutrient availability. We aimed to identify the strongest links in C:N:P stoichiometry among all rhizosphere components. A total of eight grass species (from conservative to exploitative) were grown in pots under two different soil C:nutrient conditions for a month. As a result, a wide gradient of plant–microbial–soil interactions were created. A total of 43 variables of plants, exudates, microbial and soil C:N:P stoichiometry, and PFTs were evaluated. The variables were merged into four groups in a network analysis, allowing us to identify the strongest connections among the variables and the biological meaning of these groups. The plant–soil interactions were shaped by soil N availability. Faster-growing plants were associated with lower amounts of mineral N (and P) in the soil solution, inducing a stronger competition for N with microorganisms in the rhizosphere compared to slower-growing plants. The plants responded by enhancing their N use efficiency and root:shoot ratio, and they reduced N losses via exudation. Root growth was supported either by reallocated foliar reserves or by enhanced ammonium uptake, which connected the specific leaf area (SLA) to the mineral N availability in the soil. Rapid plant growth enhanced the exudation flux. The exudates were rich in C and P relative to N compounds and served to release surplus metabolic products. The exudate C:N:P stoichiometry and soil N availability combined to shape the microbial stoichiometry, and N and P mining. In conclusion, the exudate flux and its C:N:P stoichiometry reflected the plant growth rate and nutrient constraints with a high degree of reliability. Furthermore, it mediated the plant–microbial interactions in the rhizosphere.
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15
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Polman EMN, Gruter GJM, Parsons JR, Tietema A. Comparison of the aerobic biodegradation of biopolymers and the corresponding bioplastics: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 753:141953. [PMID: 32896737 DOI: 10.1016/j.scitotenv.2020.141953] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/21/2020] [Accepted: 08/22/2020] [Indexed: 06/11/2023]
Abstract
Biodegradable plastics made from biopolymers (made in nature) or from bio-based polymers (made in a factory) are becoming increasingly important in replacing the massive amounts of conventional, non-degradable fossil-based plastics that have been produced and disposed over the past decades. In this review we compare the biodegradation rates and mechanisms of the bioplastics thermoplastic starch, cellulose acetate and lignin based bioplastics with the biodegradation rates and mechanisms of starch, cellulose and lignin, which are the unmodified biopolymers from which these bioplastics are produced. With this comparison we aim to determine to what extent the extensive knowledge on unmodified biopolymer biodegradation can be applied to the biodegradation of bioplastics (modified biopolymers) in the terrestrial environment. This knowledge is important, since it can be of great help in giving direction to the future research and development of bioplastics and for the development of bioplastic waste assessments and policies. We found that the similarities and differences in biodegradation are dependent on the structural changes imposed on a biopolymer during the bioplastic production process. A change in higher level structure, as found in thermoplastic starch, only resulted in a limited number of differences in the biodegradation process. However, when the chemical structure of a polymer is changed, as for cellulose acetate, different microorganisms and enzymes are involved in the biodegradation. Based on the cellulose acetate biodegradation process, a conceptual model was proposed that can be used as a starting point in predicting biodegradation rates of other chemically modified biopolymers used as bioplastics. Future bioplastic biodegradation research should focus on conducting long-term field experiments, since most studies are conducted in a laboratory setting and do not capture all processes occurring in the field situation. This applies even more to lignin based bioplastics, since very little experimental data were available on modified lignin biopolymer biodegradation.
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Affiliation(s)
- Emma M N Polman
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands.
| | - Gert-Jan M Gruter
- Van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands
| | - John R Parsons
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands
| | - Albert Tietema
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands
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16
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Wang HH, Chu HL, Dou Q, Feng H, Tang M, Zhang SX, Wang CY. Seasonal Changes in Pinus tabuliformis Root-Associated Fungal Microbiota Drive N and P Cycling in Terrestrial Ecosystem. Front Microbiol 2021; 11:526898. [PMID: 33537007 PMCID: PMC7849022 DOI: 10.3389/fmicb.2020.526898] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 12/04/2020] [Indexed: 11/29/2022] Open
Abstract
In terrestrial ecosystems, mycorrhizal roots play a key role in the cycling of soil carbon (C) and other nutrients. The impact of environmental factors on the mycorrhizal fungal community has been well studied; however, the seasonal variations in the root-associated fungal microbiota affected by environmental changes are less clear. To improve the understanding of how environmental factors shape the fungal microbiota in mycorrhizal roots, seasonal changes in Pinus tabuliformis root-associated fungi were investigated. In the present study, the seasonal dynamics of edaphic properties, soil enzymatic activities, root fungal colonization rates, and root-associated fungal microbiota in P. tabuliformis forests were studied across four seasons during a whole year to reveal their correlations with environmental changes. The results indicate that the soil functions, such as the enzymatic activities related to nitrogen (N) and phosphorus (P) degradation, were varied with the seasonal changes in microclimate factors, resulting in a significant fluctuation of edaphic properties. In addition, the ectomycorrhizal fungal colonization rate in the host pine tree roots increased during warm seasons (summer and autumn), while the fungal colonization rate of dark septate endophyte was declined. Moreover, the present study indicates that the fungal biomass increased in both the pine roots and rhizospheric soils during warm seasons, while the fungal species richness and diversity decreased. While the Basidiomycota and Ascomycota were the two dominant phyla in both root and soil fungal communities, the higher relative abundance of Basidiomycota taxa presented in warm seasons. In addition, the fungal microbial network complexity declined under the higher temperature and humidity conditions. The present study illustrates that the varieties in connectivity between the microbial networks and in functional taxa of root-associated fungal microbiota significantly influence the soil ecosystem functions, especially the N and P cycling.
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Affiliation(s)
- Hai-Hua Wang
- College of Forestry, Northwest A&F University, Yangling, China
- Department of Food Science and Technology, College of Agriculture and Biotechnology, Chungnam National University, Daejeon, South Korea
| | - Hong-Long Chu
- College of Forestry, Northwest A&F University, Yangling, China
- College of Biological Resource and Food Engineering, Center for Yunnan Plateau Biological Resources Protection and Utilization, Qujing Normal University, Qujing, China
| | - Qing Dou
- College of Forestry, Northwest A&F University, Yangling, China
| | - Huan Feng
- College of Forestry, Northwest A&F University, Yangling, China
| | - Ming Tang
- College of Forestry, Northwest A&F University, Yangling, China
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Shuo-Xin Zhang
- College of Forestry, Northwest A&F University, Yangling, China
- Qinling National Forest Ecosystem Research Station, Huoditang, Ningshan, China
| | - Chun-Yan Wang
- College of Forestry, Northwest A&F University, Yangling, China
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Root Fungal Endophytes and Microbial Extracellular Enzyme Activities Show Patterned Responses in Tall Fescues under Drought Conditions. AGRONOMY-BASEL 2020. [DOI: 10.3390/agronomy10081076] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Plant response to water stress can be modified by the rhizosphere microbial community, but the range of responses across plant genotypes is unclear. We imposed drought conditions on 116 Festuca arundinacea (tall fescue) accessions using a rainout shelter for 46 days, followed by irrigation, to stimulate drought recovery in 24 days. We hypothesized that prolonged water deficit results in a range of phenotypic diversity (i.e., green color index) across tall fescue genotypes that are associated with distinct microbial taxonomic and functional traits impacting plant drought tolerance. Microbial extracellular enzyme activities of chitinase and phenol oxidase (targeting chitin and lignin) increased in rhizospheres of the 20 most drought tolerant genotypes. Lower rates of fungal (dark septate) endophyte root infection were found in roots of the most drought tolerant genotypes. Bacterial 16S rRNA gene and fungal ITS sequencing showed shifts in microbial communities across water deficit conditions prior to drought, during drought, and at drought recovery, but was not patterned by drought tolerance levels of the plant host. The results suggest that taxonomic information from bacterial 16S rRNA gene and fungal ITS sequences provided little indication of microbial composition impacting drought tolerance of the host plant, but instead, microbial extracellular enzyme activities and root fungal infection results revealed patterned responses from drought.
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18
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Nunan N, Schmidt H, Raynaud X. The ecology of heterogeneity: soil bacterial communities and C dynamics. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190249. [PMID: 32200737 PMCID: PMC7133523 DOI: 10.1098/rstb.2019.0249] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2020] [Indexed: 12/15/2022] Open
Abstract
Heterogeneity is a fundamental property of soil that is often overlooked in microbial ecology. Although it is generally accepted that the heterogeneity of soil underpins the emergence and maintenance of microbial diversity, the profound and far-reaching consequences that heterogeneity can have on many aspects of microbial ecology and activity have yet to be fully apprehended and have not been fully integrated into our understanding of microbial functioning. In this contribution we first discuss how the heterogeneity of the soil microbial environment, and the consequent uncertainty associated with acquiring resources, may have affected how microbial metabolism, motility and interactions evolved and, ultimately, the overall microbial activity that is represented in ecosystem models, such as heterotrophic decomposition or respiration. We then present an analysis of predicted metabolic pathways for soil bacteria, obtained from the MetaCyc pathway/genome database collection (https://metacyc.org/). The analysis suggests that while there is a relationship between phylogenic affiliation and the catabolic range of soil bacterial taxa, there does not appear to be a trade-off between the 16S rRNA gene copy number, taken as a proxy of potential growth rate, of bacterial strains and the range of substrates that can be used. Finally, we present a simple, spatially explicit model that can be used to understand how the interactions between decomposers and environmental heterogeneity affect the bacterial decomposition of organic matter, suggesting that environmental heterogeneity might have important consequences on the variability of this process. This article is part of the theme issue 'Conceptual challenges in microbial community ecology'.
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Affiliation(s)
- Naoise Nunan
- Sorbonne Université, CNRS, IRD, INRA, P7, UPEC, Institute of Ecology and Environmental Sciences—Paris, 4 place Jussieu, 75005 Paris, France
| | - Hannes Schmidt
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna 1090, Austria
| | - Xavier Raynaud
- Sorbonne Université, CNRS, IRD, INRA, P7, UPEC, Institute of Ecology and Environmental Sciences—Paris, 4 place Jussieu, 75005 Paris, France
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19
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Männistö M, Vuosku J, Stark S, Saravesi K, Suokas M, Markkola A, Martz F, Rautio P. Bacterial and fungal communities in boreal forest soil are insensitive to changes in snow cover conditions. FEMS Microbiol Ecol 2019; 94:5043222. [PMID: 29939247 DOI: 10.1093/femsec/fiy123] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 06/22/2018] [Indexed: 02/06/2023] Open
Abstract
The northern regions are experiencing considerable changes in winter climate leading to more frequent warm periods, rain-on-snow events and reduced snow pack diminishing the insulation properties of snow cover and increasing soil frost and freeze-thaw cycles. In this study, we investigated how the lack of snow cover, formation of ice encasement and snow compaction affect the size, structure and activities of soil bacterial and fungal communities. Contrary to our hypotheses, snow manipulation treatments over one winter had limited influence on microbial community structure, bacterial or fungal copy numbers or enzyme activities. However, microbial community structure and activities shifted seasonally among soils sampled before snow melt, in early and late growing season and seemed driven by substrate availability. Bacterial and fungal communities were dominated by stress-resistant taxa such as the orders Acidobacteriales, Chaetothyriales and Helotiales that are likely adapted to adverse winter conditions. This study indicated that microbial communities in acidic northern boreal forest soil may be insensitive to direct effects of changing snow cover. However, in long term, the detrimental effects of increased ice and frost to plant roots may alter plant derived carbon and nutrient pools to the soil likely leading to stronger microbial responses.
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Affiliation(s)
- Minna Männistö
- Natural Resources Institute Finland, P.O. Box 16, FI-96301 Rovaniemi, Finland
| | - Jaana Vuosku
- Natural Resources Institute Finland, P.O. Box 16, FI-96301 Rovaniemi, Finland
| | - Sari Stark
- Natural Resources Institute Finland, P.O. Box 16, FI-96301 Rovaniemi, Finland.,Arctic Centre, University of Lapland, P.O. Box 122, FI-96101 Rovaniemi, Finland
| | - Karita Saravesi
- Department of Ecology and Genetics, P.O. Box 3000, FI-90014 University of Oulu, Finland
| | - Marko Suokas
- Department of Ecology and Genetics, P.O. Box 3000, FI-90014 University of Oulu, Finland
| | - Annamari Markkola
- Department of Ecology and Genetics, P.O. Box 3000, FI-90014 University of Oulu, Finland
| | - Françoise Martz
- Natural Resources Institute Finland, P.O. Box 16, FI-96301 Rovaniemi, Finland
| | - Pasi Rautio
- Natural Resources Institute Finland, P.O. Box 16, FI-96301 Rovaniemi, Finland
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20
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Short-Term Response of the Soil Microbial Abundances and Enzyme Activities to Experimental Warming in a Boreal Peatland in Northeast China. SUSTAINABILITY 2019. [DOI: 10.3390/su11030590] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Global warming is likely to influence the soil microorganisms and enzyme activity and alter the carbon and nitrogen balance of peatland ecosystems. To investigate the difference in sensitivities of carbon and nitrogen cycling microorganisms and enzyme activity to warming, we conducted three-year warming experiments in a boreal peatland. Our findings demonstrated that both mcrA and nirS gene abundance in shallow soil and deep soil exhibited insensitivity to warming, while shallow soil archaea 16S rRNA gene and amoA gene abundance in both shallow soil and deep soil increased under warming. Soil pmoA gene abundance of both layers, bacterial 16S rRNA gene abundance in shallow soil, and nirK gene abundance in deep soil decreased due to warming. The decreases of these gene abundances would be a result of losing labile substrates because of the competitive interactions between aboveground plants and underground soil microorganisms. Experimental warming inhibited β-glucosidase activity in two soil layers and invertase activity in deep soil, while it stimulated acid phosphatase activity in shallow soil. Both temperature and labile substrates regulate the responses of soil microbial abundances and enzyme activities to warming and affect the coupling relationships of carbon and nitrogen. This study provides a potential microbial mechanism controlling carbon and nitrogen cycling in peatland under climate warming.
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21
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Ludwig SM, Alexander HD, Kielland K, Mann PJ, Natali SM, Ruess RW. Fire severity effects on soil carbon and nutrients and microbial processes in a Siberian larch forest. GLOBAL CHANGE BIOLOGY 2018; 24:5841-5852. [PMID: 30230664 DOI: 10.1111/gcb.14455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 08/29/2018] [Accepted: 09/07/2018] [Indexed: 06/08/2023]
Abstract
Fire frequency and severity are increasing in tundra and boreal regions as climate warms, which can directly affect climate feedbacks by increasing carbon (C) emissions from combustion of the large soil C pool and indirectly via changes in vegetation, permafrost thaw, hydrology, and nutrient availability. To better understand the direct and indirect effects of changing fire regimes in northern ecosystems, we examined how differences in soil burn severity (i.e., extent of soil organic matter combustion) affect soil C, nitrogen (N), and phosphorus (P) availability and microbial processes over time. We created experimental burns of three fire severities (low, moderate, and high) in a larch forest in the northeastern Siberian Arctic and analyzed soils at 1, 8 days, and 1 year postfire. Labile dissolved C and N increased with increasing soil burn severity immediately (1 day) postfire by up to an order of magnitude, but declined significantly 1 week later; both variables were comparable or lower than unburned soils by 1 year postfire. Soil burn severity had no effect on P in the organic layer, but P increased with increasing severity in mineral soil horizons. Most extracellular enzyme activities decreased by up to 70% with increasing soil burn severity. Increasing soil burn severity reduced soil respiration 1 year postfire by 50%. However, increasing soil burn severity increased net N mineralization rates 1 year postfire, which were 10-fold higher in the highest burn severity. While fires of high severity consumed approximately five times more soil C than those of low severity, soil C pools will also be driven by indirect effects of fire on soil processes. Our data suggest that despite an initial increase in labile C and nutrients with soil burn severity, soil respiration and extracellular activities related to the turnover of organic matter were greatly reduced, which may mitigate future C losses following fire.
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Affiliation(s)
| | - Heather D Alexander
- Department of Forestry, Forest and Wildlife Research Center, Mississippi State University, Starkville, Mississippi
| | - Knut Kielland
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska
| | - Paul J Mann
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | | | - Roger W Ruess
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska
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22
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Rusterholz HP, Schneuwly J, Baur B. Invasion of the alien shrub Prunus laurocerasus in suburban deciduous forests: Effects on native vegetation and soil properties. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2018. [DOI: 10.1016/j.actao.2018.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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23
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Initial Soil Organic Matter Content Influences the Storage and Turnover of Litter, Root and Soil Carbon in Grasslands. Ecosystems 2018. [DOI: 10.1007/s10021-018-0227-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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24
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Understanding the influence of urbanization on invasibility: Carpobrotus edulis as an exemplar. Biol Invasions 2017. [DOI: 10.1007/s10530-017-1593-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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25
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Naylor D, Coleman-Derr D. Drought Stress and Root-Associated Bacterial Communities. FRONTIERS IN PLANT SCIENCE 2017; 8:2223. [PMID: 29375600 PMCID: PMC5767233 DOI: 10.3389/fpls.2017.02223] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 12/18/2017] [Indexed: 05/20/2023]
Abstract
Root-associated bacterial communities play a vital role in maintaining health of the plant host. These communities exist in complex relationships, where composition and abundance of community members is dependent on a number of factors such as local soil chemistry, plant genotype and phenotype, and perturbations in the surrounding abiotic environment. One common perturbation, drought, has been shown to have drastic effects on bacterial communities, yet little is understood about the underlying causes behind observed shifts in microbial abundance. As drought may affect root bacterial communities both directly by modulating moisture availability, as well as indirectly by altering soil chemistry and plant phenotypes, we provide a synthesis of observed trends in recent studies and discuss possible directions for future research that we hope will provide for more knowledgeable predictions about community responses to future drought events.
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Affiliation(s)
- Dan Naylor
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
- Plant Gene Expression Center, United States Department of Agriculture-Agricultural Research Service, Albany, CA, United States
| | - Devin Coleman-Derr
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
- Plant Gene Expression Center, United States Department of Agriculture-Agricultural Research Service, Albany, CA, United States
- *Correspondence: Devin Coleman-Derr,
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26
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Sarmento H, Morana C, Gasol JM. Bacterioplankton niche partitioning in the use of phytoplankton-derived dissolved organic carbon: quantity is more important than quality. ISME JOURNAL 2016; 10:2582-2592. [PMID: 27128994 DOI: 10.1038/ismej.2016.66] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 03/18/2016] [Accepted: 03/23/2016] [Indexed: 11/09/2022]
Abstract
Some prokaryotes are known to be specialized in the use of phytoplankton-derived dissolved organic carbon (DOCp) originated by exudation or cell lysis; however, direct quantification measurements are extremely rare. Several studies have described bacterial selectivity based on DOCp quality, but very few have focused on the quantity of DOCp, and the relative importance of each of these variables (for example, quantity versus quality) on prokaryote responses. We applied an adapted version of the MAR-FISH (microautoradiography coupled with catalyzed reporter deposition fluorescence in situ hybridization) protocol using radiolabelled exudates from axenic algal cultures to calculate a specialization index (d') for large bacterioplankton phylogenetic groups using DOCp from different phytoplankton species and at different concentrations to elucidate to what extent the bacterial response to DOCp is driven by resource quantity (different DOCp concentrations) or by quality (DOCp from different phytoplankton species). All bacterial phylogenetic groups studied had lower d' at higher DOCp concentration, indicating more generalist behavior at higher resource availabilities. Indeed, at increasing resource concentrations, most bacterial groups incorporated DOCp indiscriminately, regardless of its origin (or quality). At low resource concentrations, only some specialists were able to actively incorporate the various types of organic matter effectively. The variability of bacterial responses to different treatments was systematically higher at varying concentrations than at varying DOCp types, suggesting that, at least for this range of concentrations (10-100 μM), DOCp quantity affects bacterial responses more than quality does. Therefore, resource quantity may be more relevant than resource quality in the bacterial responses to DOCp and affect how bacterioplankton use phytoplankton-derived carbon.
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Affiliation(s)
- Hugo Sarmento
- Department of Hydrobiology, Federal University of São Carlos (UFSCar), São Carlos, Brazil.,Institut de Ciències del Mar-CSIC, Pg. Marítim de la Barceloneta, Barcelona, Spain
| | - Cédric Morana
- Department of Earth and Environmental Sciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Josep M Gasol
- Institut de Ciències del Mar-CSIC, Pg. Marítim de la Barceloneta, Barcelona, Spain
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27
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Steinauer K, Tilman D, Wragg PD, Cesarz S, Cowles JM, Pritsch K, Reich PB, Weisser WW, Eisenhauer N. Plant diversity effects on soil microbial functions and enzymes are stronger than warming in a grassland experiment. Ecology 2015; 96:99-112. [DOI: 10.1890/14-0088.1] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Katja Steinauer
- Friedrich Schiller University Jena, Institute of Ecology, Dornburger Strasse 159, 07743 Jena, Germany
- Technische Universität München, Department of Ecology and Ecosystem Management, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - David Tilman
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, Minnesota 55108 USA
| | - Peter D. Wragg
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, Minnesota 55108 USA
| | - Simone Cesarz
- Friedrich Schiller University Jena, Institute of Ecology, Dornburger Strasse 159, 07743 Jena, Germany
| | - Jane M. Cowles
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, Minnesota 55108 USA
| | - Karin Pritsch
- Institute of Soil Ecology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Peter B. Reich
- Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue North, St. Paul, Minnesota 55108 USA
- Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, New South Wales 2753 Australia
| | - Wolfgang W. Weisser
- Technische Universität München, Department of Ecology and Ecosystem Management, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - Nico Eisenhauer
- Friedrich Schiller University Jena, Institute of Ecology, Dornburger Strasse 159, 07743 Jena, Germany
- Technische Universität München, Department of Ecology and Ecosystem Management, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
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28
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Purahong W, Schloter M, Pecyna MJ, Kapturska D, Däumlich V, Mital S, Buscot F, Hofrichter M, Gutknecht JLM, Krüger D. Uncoupling of microbial community structure and function in decomposing litter across beech forest ecosystems in Central Europe. Sci Rep 2014; 4:7014. [PMID: 25388562 PMCID: PMC4228342 DOI: 10.1038/srep07014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 10/15/2014] [Indexed: 01/19/2023] Open
Abstract
The widespread paradigm in ecology that community structure determines function has recently been challenged by the high complexity of microbial communities. Here, we investigate the patterns of and connections between microbial community structure and microbially-mediated ecological function across different forest management practices and temporal changes in leaf litter across beech forest ecosystems in Central Europe. Our results clearly indicate distinct pattern of microbial community structure in response to forest management and time. However, those patterns were not reflected when potential enzymatic activities of microbes were measured. We postulate that in our forest ecosystems, a disconnect between microbial community structure and function may be present due to differences between the drivers of microbial growth and those of microbial function.
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Affiliation(s)
- Witoon Purahong
- 1] UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany [2] Technical University of Munich, Chair for Soil Science, Ingolstädter Landstr. 1, D-85758 Oberschleissheim, Germany
| | - Michael Schloter
- Helmholtz Zentrum München, Research Unit for Environmental Genomics, Ingolstädter Landstr. 1, D-85758 Oberschleissheim, Germany
| | - Marek J Pecyna
- Dresden University of Technology (TU Dresden) - International Institute (IHI) Zittau, Markt 23, D-02763 Zittau, Germany
| | - Danuta Kapturska
- 1] UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany [2] Dresden University of Technology (TU Dresden) - International Institute (IHI) Zittau, Markt 23, D-02763 Zittau, Germany
| | - Veronika Däumlich
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany
| | - Sanchit Mital
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany
| | - François Buscot
- 1] UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany [2] University of Leipzig, Institute of Biology, Johannisallee 21-23, D-04103 Leipzig, Germany [3] German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany
| | - Martin Hofrichter
- Dresden University of Technology (TU Dresden) - International Institute (IHI) Zittau, Markt 23, D-02763 Zittau, Germany
| | - Jessica L M Gutknecht
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany
| | - Dirk Krüger
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany
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29
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Biogeochemical Hotspots in Forested Landscapes: The Role of Vernal Pools in Denitrification and Organic Matter Processing. Ecosystems 2014. [DOI: 10.1007/s10021-014-9807-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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30
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Averill C. Divergence in plant and microbial allocation strategies explains continental patterns in microbial allocation and biogeochemical fluxes. Ecol Lett 2014; 17:1202-10. [DOI: 10.1111/ele.12324] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/03/2014] [Accepted: 06/12/2014] [Indexed: 11/25/2022]
Affiliation(s)
- Colin Averill
- Department of Integrative Biology Graduate Program in Ecology, Evolution and Behavior University of Texas at Austin Austin TX 78712 USA
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31
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Qiao N, Schaefer D, Blagodatskaya E, Zou X, Xu X, Kuzyakov Y. Labile carbon retention compensates for CO2 released by priming in forest soils. GLOBAL CHANGE BIOLOGY 2014; 20:1943-1954. [PMID: 24293210 DOI: 10.1111/gcb.12458] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 10/17/2013] [Indexed: 06/02/2023]
Abstract
Increase of belowground C allocation by plants under global warming or elevated CO2 may promote decomposition of soil organic carbon (SOC) by priming and strongly affects SOC dynamics. The specific effects by priming of SOC depend on the amount and frequency of C inputs. Most previous priming studies have investigated single C additions, but they are not very representative for litterfall and root exudation in many terrestrial ecosystems. We evaluated effects of (13)C-labeled glucose added to soil in three temporal patterns: single, repeated, and continuous on dynamics of CO2 and priming of SOC decomposition over 6 months. Total and (13)C labeled CO2 were monitored to analyze priming dynamics and net C balance between SOC loss caused by priming and the retention of added glucose-C. Cumulative priming ranged from 1.3 to 5.5 mg C g(-1) SOC in the subtropical, and from -0.6 to 5.5 mg C g(-1) SOC in the tropical soils. Single addition induced more priming than repeated and continuous inputs. Therefore, single additions of high substrate amounts may overestimate priming effects over the short term. The amount of added glucose C remaining in soil after 6 months (subtropical: 8.1-11.2 mg C g(-1) SOC or 41-56% of added glucose; tropical: 8.7-15.0 mg C g(-1) SOC or 43-75% of glucose) was substantially higher than the net C loss due to SOC decomposition including priming effect. This overcompensation of C losses was highest with continuous inputs and lowest with single inputs. Therefore, raised labile organic C input to soils by higher plant productivity will increase SOC content even though priming accelerates decomposition of native SOC. Consequently, higher continuous input of C belowground by plants under warming or elevated CO2 can increase C stocks in soil despite accelerated C cycling by priming in soils.
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Affiliation(s)
- Na Qiao
- Key Laboratory of Tropical Forest Ecology, Chinese Academy of Sciences, Xishuangbanna Tropical Botanical Garden, Menglun, Mengla, Yunnan, 666303, China; Graduate School of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China
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32
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Bell CW, Fricks BE, Rocca JD, Steinweg JM, McMahon SK, Wallenstein MD. High-throughput fluorometric measurement of potential soil extracellular enzyme activities. J Vis Exp 2013:e50961. [PMID: 24299913 PMCID: PMC3991303 DOI: 10.3791/50961] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Microbes in soils and other environments produce extracellular enzymes to depolymerize and hydrolyze organic macromolecules so that they can be assimilated for energy and nutrients. Measuring soil microbial enzyme activity is crucial in understanding soil ecosystem functional dynamics. The general concept of the fluorescence enzyme assay is that synthetic C-, N-, or P-rich substrates bound with a fluorescent dye are added to soil samples. When intact, the labeled substrates do not fluoresce. Enzyme activity is measured as the increase in fluorescence as the fluorescent dyes are cleaved from their substrates, which allows them to fluoresce. Enzyme measurements can be expressed in units of molarity or activity. To perform this assay, soil slurries are prepared by combining soil with a pH buffer. The pH buffer (typically a 50 mM sodium acetate or 50 mM Tris buffer), is chosen for the buffer's particular acid dissociation constant (pKa) to best match the soil sample pH. The soil slurries are inoculated with a nonlimiting amount of fluorescently labeled (i.e. C-, N-, or P-rich) substrate. Using soil slurries in the assay serves to minimize limitations on enzyme and substrate diffusion. Therefore, this assay controls for differences in substrate limitation, diffusion rates, and soil pH conditions; thus detecting potential enzyme activity rates as a function of the difference in enzyme concentrations (per sample). Fluorescence enzyme assays are typically more sensitive than spectrophotometric (i.e. colorimetric) assays, but can suffer from interference caused by impurities and the instability of many fluorescent compounds when exposed to light; so caution is required when handling fluorescent substrates. Likewise, this method only assesses potential enzyme activities under laboratory conditions when substrates are not limiting. Caution should be used when interpreting the data representing cross-site comparisons with differing temperatures or soil types, as in situ soil type and temperature can influence enzyme kinetics.
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Affiliation(s)
- Colin W Bell
- Natural Resource Ecology Laboratory, Colorado State University
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33
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Steinweg JM, Dukes JS, Paul EA, Wallenstein MD. Microbial responses to multi-factor climate change: effects on soil enzymes. Front Microbiol 2013; 4:146. [PMID: 23781218 PMCID: PMC3678102 DOI: 10.3389/fmicb.2013.00146] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 05/24/2013] [Indexed: 11/13/2022] Open
Abstract
The activities of extracellular enzymes, the proximate agents of decomposition in soils, are known to depend strongly on temperature, but less is known about how they respond to changes in precipitation patterns, and the interaction of these two components of climate change. Both enzyme production and turnover can be affected by changes in temperature and soil moisture, thus it is difficult to predict how enzyme pool size may respond to altered climate. Soils from the Boston-Area Climate Experiment (BACE), which is located in an old field (on abandoned farmland), were used to examine how climate variables affect enzyme activities and microbial biomass carbon (MBC) in different seasons and in soils exposed to a combination of three levels of precipitation treatments (ambient, 150% of ambient during growing season, and 50% of ambient year-round) and four levels of warming treatments (unwarmed to ~4°C above ambient) over the course of a year. Warming, precipitation and season had very little effect on potential enzyme activity. Most models assume that enzyme dynamics follow microbial biomass, because enzyme production should be directly controlled by the size and activity of microbial biomass. We observed differences among seasons and treatments in mass-specific potential enzyme activity, suggesting that this assumption is invalid. In June 2009, mass-specific potential enzyme activity, using chloroform fumigation-extraction MBC, increased with temperature, peaking under medium warming and then declining under the highest warming. This finding suggests that either enzyme production increased with temperature or turnover rates decreased. Increased maintenance costs associated with warming may have resulted in increased mass-specific enzyme activities due to increased nutrient demand. Our research suggests that allocation of resources to enzyme production could be affected by climate-induced changes in microbial efficiency and maintenance costs.
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Affiliation(s)
- J Megan Steinweg
- Natural Resource Ecology Laboratory, Colorado State University Fort Collins, CO, USA ; Graduate Degree Program in Ecology, Colorado State University Fort Collins, CO, USA
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34
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Kuzyakov Y, Xu X. Competition between roots and microorganisms for nitrogen: mechanisms and ecological relevance. THE NEW PHYTOLOGIST 2013; 198:656-669. [PMID: 23521345 DOI: 10.1111/nph.12235] [Citation(s) in RCA: 328] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 02/18/2013] [Indexed: 05/06/2023]
Abstract
Demand of all living organisms on the same nutrients forms the basis for interspecific competition between plants and microorganisms in soils. This competition is especially strong in the rhizosphere. To evaluate competitive and mutualistic interactions between plants and microorganisms and to analyse ecological consequences of these interactions, we analysed 424 data pairs from 41 (15)N-labelling studies that investigated (15)N redistribution between roots and microorganisms. Calculated Michaelis-Menten kinetics based on K(m) (Michaelis constant) and V(max) (maximum uptake capacity) values from 77 studies on the uptake of nitrate, ammonia, and amino acids by roots and microorganisms clearly showed that, shortly after nitrogen (N) mobilization from soil organic matter and litter, microorganisms take up most N. Lower K(m) values of microorganisms suggest that they are especially efficient at low N concentrations, but can also acquire more N at higher N concentrations (V(max)) compared with roots. Because of the unidirectional flow of nutrients from soil to roots, plants are the winners for N acquisition in the long run. Therefore, despite strong competition between roots and microorganisms for N, a temporal niche differentiation reflecting their generation times leads to mutualistic relationships in the rhizosphere. This temporal niche differentiation is highly relevant ecologically because it: protects ecosystems from N losses by leaching during periods of slow or no root uptake; continuously provides roots with available N according to plant demand; and contributes to the evolutionary development of mutualistic interactions between roots and microorganisms.
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Affiliation(s)
- Yakov Kuzyakov
- Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences (CAS), PO Box 9725, Beijing, 100101, China
- Department of Soil Science of Temperate Ecosystems, Göttingen, Germany
- Department of Agricultural Soil Science, University of Göttingen, Göttingen, Germany
| | - Xingliang Xu
- Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences (CAS), PO Box 9725, Beijing, 100101, China
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35
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Brzostek ER, Finzi AC. Seasonal variation in the temperature sensitivity of proteolytic enzyme activity in temperate forest soils. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jg001688] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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