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Määttä T, Malhotra A. The hidden roots of wetland methane emissions. GLOBAL CHANGE BIOLOGY 2024; 30:e17127. [PMID: 38337165 DOI: 10.1111/gcb.17127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/24/2023] [Accepted: 12/02/2023] [Indexed: 02/12/2024]
Abstract
Wetlands are the largest natural source of methane (CH4 ) globally. Climate and land use change are expected to alter CH4 emissions but current and future wetland CH4 budgets remain uncertain. One important predictor of wetland CH4 flux, plants, play an important role in providing substrates for CH4 -producing microbes, increasing CH4 consumption by oxygenating the rhizosphere, and transporting CH4 from soils to the atmosphere. Yet, there remain various mechanistic knowledge gaps regarding the extent to which plant root systems and their traits influence wetland CH4 emissions. Here, we present a novel conceptual framework of the relationships between a range of root traits and CH4 processes in wetlands. Based on a literature review, we propose four main CH4 -relevant categories of root function: gas transport, carbon substrate provision, physicochemical influences and root system architecture. Within these categories, we discuss how individual root traits influence CH4 production, consumption, and transport (PCT). Our findings reveal knowledge gaps concerning trait functions in physicochemical influences, and the role of mycorrhizae and temporal root dynamics in PCT. We also identify priority research needs such as integrating trait measurements from different root function categories, measuring root-CH4 linkages along environmental gradients, and following standardized root ecology protocols and vocabularies. Thus, our conceptual framework identifies relevant belowground plant traits that will help improve wetland CH4 predictions and reduce uncertainties in current and future wetland CH4 budgets.
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Affiliation(s)
- Tiia Määttä
- Department of Geography, University of Zürich, Zürich, Switzerland
| | - Avni Malhotra
- Department of Geography, University of Zürich, Zürich, Switzerland
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
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Tang Y, Qin D, Tian Z, Chen W, Ma Y, Wang J, Yang J, Yan D, Dixon R, Wang YP. Diurnal switches in diazotrophic lifestyle increase nitrogen contribution to cereals. Nat Commun 2023; 14:7516. [PMID: 37980355 PMCID: PMC10657418 DOI: 10.1038/s41467-023-43370-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 11/07/2023] [Indexed: 11/20/2023] Open
Abstract
Uncoupling of biological nitrogen fixation from ammonia assimilation is a prerequisite step for engineering ammonia excretion and improvement of plant-associative nitrogen fixation. In this study, we have identified an amino acid substitution in glutamine synthetase, which provides temperature sensitive biosynthesis of glutamine, the intracellular metabolic signal of the nitrogen status. As a consequence, negative feedback regulation of genes and enzymes subject to nitrogen regulation, including nitrogenase is thermally controlled, enabling ammonia excretion in engineered Escherichia coli and the plant-associated diazotroph Klebsiella oxytoca at 23 °C, but not at 30 °C. We demonstrate that this temperature profile can be exploited to provide diurnal oscillation of ammonia excretion when variant bacteria are used to inoculate cereal crops. We provide evidence that diurnal temperature variation improves nitrogen donation to the plant because the inoculant bacteria have the ability to recover and proliferate at higher temperatures during the daytime.
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Affiliation(s)
- Yuqian Tang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Debin Qin
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Zhexian Tian
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Wenxi Chen
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Yuanxi Ma
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Jilong Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Jianguo Yang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Dalai Yan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK.
| | - Yi-Ping Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China.
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Nyer SC, Volkenborn N, Aller RC, Graffam M, Zhu Q, Price RE. Nitrogen transformations in constructed wetlands: A closer look at plant-soil interactions using chemical imaging. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 816:151560. [PMID: 34785218 DOI: 10.1016/j.scitotenv.2021.151560] [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: 08/19/2021] [Revised: 10/24/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
Constructed wetlands have long been used for domestic wastewater treatment. Despite the widespread application of constructed wetlands for wastewater remediation, they are still regarded as a black box in terms of the complex biogeochemical processes occurring internally, particularly with respect to plant-soil (and nitrogen) interactions. Additionally, many critical processes pertaining to nitrogen transformations in constructed wetlands are thought to occur in microzones within the rhizosphere, highlighting the need for studies with sub-cm spatial resolution. In this study we coupled nitrogen porewater measurements with chemical imaging to determine spatio-temporal patterns in porewater O2 and pH to assess the extent of plant-induced changes in soil redox dynamics that influence nitrogen biogeochemical cycling during dosed application of nitrogen-rich artificial wastewater. Planar optode imaging revealed extensive O2 fluxes to otherwise anoxic sediment via radial oxygen loss (ROL) from Typha latifolia roots. The contribution of photosynthetic O2 from this plant species was minimal as a strong oxic signal persisted in darkness (diel cycles). NH4+ and NOx- removal were strongly correlated with the extent of oxic and anoxic areas, a function largely attributed to the presence of plants and the associated enhanced microbial communities supported. The distribution of nitrogen species within the Typha rhizosphere exhibited reproducible trends as a function of distance from roots, with concentrations highest close to roots (1-5 mm from root surface) and subsequently decreasing at greater distances. Microscale spatio-temporal redox heterogeneity within the rhizosphere due to ROL imposed by plants promoted nitrogen removal likely by stimulating the coupling between nitrification and denitrification in these systems. Collectively, this study highlights the profound importance of plants in exerting controls on soil conditions and nitrogen cycling in constructed wetland systems. With careful considerations, constructed wetlands designed to promote wetland plants' functions may enhance nitrogen removal and mitigate nitrogen pollution.
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Affiliation(s)
- Samantha C Nyer
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA; The New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Nils Volkenborn
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA; The New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Robert C Aller
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Molly Graffam
- Cornell Cooperative Extension of Suffolk County, Riverhead, NY 11901, USA
| | - Qingzhi Zhu
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA; The New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Roy E Price
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA; The New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY 11794, USA
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Woodward KB, Hofstra D. Rhizosphere metabolism and its effect on phosphorus pools in the root zone of a submerged macrophyte, Isoëtes kirkii. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 809:151087. [PMID: 34687706 DOI: 10.1016/j.scitotenv.2021.151087] [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: 05/08/2021] [Revised: 09/27/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
The presence of oxygen in lake sediments reduces sediment oxygen demand, and potentially improves sediment phosphorus retention and coupled nitrification/denitrification. However, the release of oxygen from the roots of macrophytes has not previously been measured in highly reducing sediments. Here, in the highly reducing environments of a commercial garden soil and sediment from a hyper-eutrophic lake, we used nine oxygen optodes, placed onto scintillation vials to detect oxygen in the rhizosphere of Isoetes kirkii referred to as quillworts. We calculated rhizosphere metabolism using "night-time regression" a method designed to estimate stream metabolism at the reach scale. After the incubations, sediment was collected from each vial (with and without macrophytes) and was subjected to sequential phosphorus extractions. A lag period between light availability and increasing oxygen concentration, that varied between individual optodes, was used to improve the accuracy of metabolism estimates as it was postulated to represent the distance between the root and the optode. Higher sediment oxygen demand in the lake sediment caused I. kirkii to have higher root oxygen release than those plants grown in the garden soil and may have pushed plants in lake sediment close to their ability to survive. This was evident as a significant, negative relationship between root oxygen release and increasing sediment oxygen demand, indicating that if photosynthesis decreased or sediment oxygen demand increased, the plants would no longer being able to oxygenate the sediment surrounding their roots, which would likely lead to death. Finally, the presence of quillworts in lake sediments significantly increased stores of metal oxide and recalcitrant phosphorus in the lake sediment but not the garden soil.
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Affiliation(s)
- K Benjamin Woodward
- National Institute of Water and Atmospheric Research Ltd, PO Box 11-115, Hamilton, New Zealand.
| | - Deborah Hofstra
- National Institute of Water and Atmospheric Research Ltd, PO Box 11-115, Hamilton, New Zealand
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Vicca S, Goll DS, Hagens M, Hartmann J, Janssens IA, Neubeck A, Peñuelas J, Poblador S, Rijnders J, Sardans J, Struyf E, Swoboda P, van Groenigen JW, Vienne A, Verbruggen E. Is the climate change mitigation effect of enhanced silicate weathering governed by biological processes? GLOBAL CHANGE BIOLOGY 2022; 28:711-726. [PMID: 34773318 DOI: 10.1111/gcb.15993] [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: 07/26/2021] [Revised: 10/04/2021] [Accepted: 11/10/2021] [Indexed: 06/13/2023]
Abstract
A number of negative emission technologies (NETs) have been proposed to actively remove CO2 from the atmosphere, with enhanced silicate weathering (ESW) as a relatively new NET with considerable climate change mitigation potential. Models calibrated to ESW rates in lab experiments estimate the global potential for inorganic carbon sequestration by ESW at about 0.5-5 Gt CO2 year-1 , suggesting ESW could be an important component of the future NETs mix. In real soils, however, weathering rates may differ strongly from lab conditions. Research on natural weathering has shown that biota such as plants, microbes, and macro-invertebrates can strongly affect weathering rates, but biotic effects were excluded from most ESW lab assessments. Moreover, ESW may alter soil organic carbon sequestration and greenhouse gas emissions by influencing physicochemical and biological processes, which holds the potential to perpetuate even larger negative emissions. Here, we argue that it is likely that the climate change mitigation effect of ESW will be governed by biological processes, emphasizing the need to put these processes on the agenda of this emerging research field.
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Affiliation(s)
- Sara Vicca
- Plants and Ecosystems (PLECO), Biology Department, University of Antwerp, Wilrijk, Belgium
| | - Daniel S Goll
- CEA-CNRS-UVSQ, LSCE/IPSL, Université Paris Saclay, Gif sur Yvette, France
| | - Mathilde Hagens
- Soil Chemistry and Chemical Soil Quality, Environmental Sciences, Wageningen University and Research, Wageningen, The Netherlands
| | - Jens Hartmann
- Institute for Geology, Center for Earth System Research and Sustainability, University of Hamburg, Hamburg, Germany
| | - Ivan A Janssens
- Plants and Ecosystems (PLECO), Biology Department, University of Antwerp, Wilrijk, Belgium
| | - Anna Neubeck
- Department of Earth sciences, Uppsala University, Uppsala, Sweden
| | - Josep Peñuelas
- CSIC, Global Ecology CREAF- CSIC-UAB, Barcelona, Spain
- CREAF, Barcelona, Spain
| | - Sílvia Poblador
- Plants and Ecosystems (PLECO), Biology Department, University of Antwerp, Wilrijk, Belgium
| | - Jet Rijnders
- Plants and Ecosystems (PLECO), Biology Department, University of Antwerp, Wilrijk, Belgium
| | - Jordi Sardans
- CSIC, Global Ecology CREAF- CSIC-UAB, Barcelona, Spain
- CREAF, Barcelona, Spain
| | - Eric Struyf
- Plants and Ecosystems (PLECO), Biology Department, University of Antwerp, Wilrijk, Belgium
| | - Philipp Swoboda
- International Centre for Sustainable Development, Bonn-Rhein-Sieg University of Applied Sciences, Sankt Augustin, Germany
| | | | - Arthur Vienne
- Plants and Ecosystems (PLECO), Biology Department, University of Antwerp, Wilrijk, Belgium
| | - Erik Verbruggen
- Plants and Ecosystems (PLECO), Biology Department, University of Antwerp, Wilrijk, Belgium
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Onodera T, Miyazaki H, Li X, Wang J, Nakayasu M, Yatabe R, Tahara Y, Hosoki A, Sakurai N, Sugiyama A. Development of two-dimensional qualitative visualization method for isoflavones secreted from soybean roots using sheets with immobilized bovine serum albumin. Biosens Bioelectron 2022; 196:113705. [PMID: 34715535 DOI: 10.1016/j.bios.2021.113705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/22/2021] [Accepted: 10/10/2021] [Indexed: 02/06/2023]
Abstract
A visualization method for the qualitative evaluation of soybean isoflavones secreted from soybean roots by transferring them onto a sheet with immobilized bovine serum albumin (BSA) was developed. BSA was chemically bonded onto a glass microfiber filter. The fluorescence quenching resulting from the interaction of BSA with soybean isoflavones such as daidzein and daidzin was utilized. Fluorescence images before and after soybean roots were placed in contact with the sheets with immobilized BSA were taken with an electron-multiplying charge-coupled device camera. The fluorescence quenching in the images was visualized and analyzed. Soybean isoflavones were extracted from the sheets for quantitative analysis, and the correlation coefficient between the quenched fluorescence intensity per sheet and the total amount of soybean isoflavones was 0.78 (p < 0.01), indicating a high correlation. The quenched fluorescence intensity was lower in pumpkin roots, which do not secrete soybean isoflavone. It was found from analyzed images that soybean isoflavone is secreted in larger amounts from the basal region of the taproot and the tips of the lateral roots of soybean.
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Affiliation(s)
- Takeshi Onodera
- Faculty of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka, 819-0395, Japan.
| | - Haruna Miyazaki
- Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka, 819-0395, Japan
| | - Xinzhu Li
- Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka, 819-0395, Japan
| | - Jin Wang
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 3-1-1 Tsushimanaka, Kitaku, Okayama, 700-8530, Japan
| | - Masaru Nakayasu
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Rui Yatabe
- Faculty of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka, 819-0395, Japan
| | - Yusuke Tahara
- Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda City, Nagano, 386-8567, Japan
| | - Ai Hosoki
- Bioinformation and DDBJ Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Nozomu Sakurai
- Bioinformation and DDBJ Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Akifumi Sugiyama
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
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Comparison of methods for mapping rhizosphere processes in the context of their surrounding root and soil environments. Biotechniques 2021; 71:604-614. [PMID: 34809497 DOI: 10.2144/btn-2021-0021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The rhizosphere embodies a complex biogeochemical zone with enhanced rates of nutrient exchange between plants, soil, and microbial communities. Understanding controls on rhizosphere dynamics is critical to support emerging concepts including rhizosphere engineering and reduced dependence on chemical fertilizers which have direct application to food production, increased biofuel generation, and habitat restoration efforts. Yet, its fine spatial scale and complex interactions between geochemical and microbial processes within complex spatiotemporal gradients make the rhizosphere notoriously difficult to study. Emerging instrumentation and methodologies, however, are providing improved resolution to rhizosphere measurements and helping to address critical knowledge gaps in rhizosphere function, ecology, and establishment. Here, we examine recent advances in analysis techniques and the resulting potential for improved understanding of rhizosphere function.
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8
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Zhang Y, Li C, Sun Q, Jiang C, Ding S, Chen M, Ma X, Zhong Z, Wang Y, Tsang DCW. Phosphorus acquisition strategy of Vallisneria natans in sediment based on in situ imaging techniques. ENVIRONMENTAL RESEARCH 2021; 202:111635. [PMID: 34242674 DOI: 10.1016/j.envres.2021.111635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/22/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
Phosphorus (P) availability is closely related to the distributions of pH, O2 and phosphatase activities in the rhizosphere of plants growing in soils and sediments. In this study, the P uptake processes and mechanisms of Vallisneria natans (V. natans) during two vegetation periods (i.e., week three and six) were revealed using three noninvasive 2D imaging techniques: planar optode (PO), diffusive gradients in thin films (DGT) and zymography. The results showed that increased phosphatase activity, O2 concentration and root-induced acidification were observed together in the rhizosphere of root segments and tips. In week three, when V. natans was young, the flux of DGT-labile P accumulated more in the rhizosphere in comparison with the bulk sediment. This was because increased phosphatase activity (of up to 35%) and root-induced acidification (with pH decreasing by up to 0.25) enhanced P acquisition of V. natans by the third week. However, the flux of DGT-labile P turned to depletion during weeks three to six of V. natans growth, after Fe plaque formed at the matured stage. The constant hydrolysis of phosphatase and acidification could not compensate for the P demand of the roots by the sixth week. At this stage, Fe plaque become the P pool, due to P fixation with solid Fe(III) hydroxides. Subsequently, V. natans roots acquired P from Fe plaque via organic acid complexation of Fe(III).
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Affiliation(s)
- Yi Zhang
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Cai Li
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Qin Sun
- College of Environment, Hohai University, Nanjing, 210098, China.
| | - Cuiling Jiang
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China.
| | - Shiming Ding
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Musong Chen
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Xin Ma
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Zhilin Zhong
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Yan Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; Nanjing EasySensor Environmental Technology Co., Ltd, Nanjing, 210018, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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Effects of Recreational Boating on Microbial and Meiofauna Diversity in Coastal Shallow Ecosystems of the Baltic Sea. mSphere 2021; 6:e0012721. [PMID: 34468165 PMCID: PMC8550262 DOI: 10.1128/msphere.00127-21] [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] [Indexed: 01/04/2023] Open
Abstract
Recreational boating can impact benthic ecosystems in coastal waters. Reduced height and cover of aquatic vegetation in shallow Baltic Sea inlets with high boat traffic have raised concerns about cascading effects on benthic communities in these ecosystems. Here, we characterized the diversity and composition of sediment-associated microbial and meiofaunal communities across five bays subjected to low and high degrees of boating activity and examined the community-environment relationships and association with bay morphometry. We found that recreational boating activity altered meiofauna alpha diversity and the composition of both micro- and meiobenthic communities, and there were strong correlations between community structure and morphometric variables like topographic openness, wave exposure, water surface area, and total phosphorous concentrations. Inlets with high boat traffic showed an increase of bacterial taxa like Hydrogenophilaceae and Burkholderiaceae. Several meiofauna taxa previously reported to respond positively to high levels of suspended organic matter were found in higher relative abundances in the bays with high boat traffic. Overall, our results show that morphometric characteristics of inlets are the strongest drivers of benthic diversity in shallow coastal environments. However, while the effects were small, we found significant effects of recreational boating on benthic community structure that should be considered when evaluating the new mooring projects. IMPORTANCE With the increase of recreational boating activity and development of boating infrastructure in shallow, wave-protected areas, there is growing concern for their impact on coastal ecosystems. In order to properly assess the effects and consider the potential for recovery, it is important to investigate microbial and meiofaunal communities that underpin the functioning of these ecosystems. Here, we present the first study that uses DNA metabarcoding to assess how benthic biodiversity in shallow coastal areas is impacted by recreational boating. Our study shows a relatively small, but significant, effect of recreational boating both on meiofauna alpha diversity and meiofauna and bacterial community composition. However, both meiofauna and bacterial community composition in shallow benthic habitats is mediated to a higher degree by abiotic variables, such as topographic openness, area or size of the inlets, and wave exposure. Despite the fact that the effects were small, such impacts on benthic biodiversity should be considered in the management of coastal shallow habitats.
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Koop-Jakobsen K, Meier RJ, Mueller P. Plant-Mediated Rhizosphere Oxygenation in the Native Invasive Salt Marsh Grass Elymus athericus. FRONTIERS IN PLANT SCIENCE 2021; 12:669751. [PMID: 34177984 PMCID: PMC8222977 DOI: 10.3389/fpls.2021.669751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/03/2021] [Indexed: 06/13/2023]
Abstract
In the last decades, the spread of Elymus athericus has caused significant changes to the plant community composition and ecosystem services of European marshes. The distribution of E. athericus was typically limited by soil conditions characteristic for high marshes, such as low flooding frequency and high soil aeration. However, recently the spread of E. athericus has begun to also include low-marsh environments. A high-marsh ecotype and a low-marsh ecotype of E. athericus have been described, where the latter possess habitat-specific phenotypic traits facilitating a better adaption for inhabiting low-marsh areas. In this study, planar optodes were applied to investigate plant-mediated sediment oxygenation in E. athericus, which is a characteristic trait for marsh plants inhabiting frequently flooded environments. Under waterlogged conditions, oxygen (O2) was translocated from aboveground sources to the roots, where it leaked out into the surrounding sediment generating oxic root zones below the sediment surface. Oxic root zones were clearly visible in the optode images, and no differences were found in the O2-leaking capacity between ecotypes. Concentration profiles measured perpendicular to the roots revealed that the radius of the oxic root zones ranged from 0.5 to 2.6 mm measured from the root surface to the bulk anoxic sediment. The variation of oxic root zones was monitored over three consecutive light-dark cycles (12 h/12 h). The O2 concentration of the oxic root zones was markedly reduced in darkness, yet the sediment still remained oxic in the immediate vicinity of the roots. Increased stomatal conductance improving the access to atmospheric O2 as well as photosynthetic O2 production are likely factors facilitating the improved rhizosphere oxygenation during light exposure of the aboveground biomass. E. athericus' capacity to oxygenate its rhizosphere is an inheritable trait that may facilitate its spread into low-marsh areas. Furthermore, this trait makes E. athericus a highly competitive species in marshes facing the effects of accelerated sea-level rise, where waterlogged sediment conditions could become increasingly pronounced.
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Affiliation(s)
- Ketil Koop-Jakobsen
- Wadden Sea Station, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), List/Sylt, Germany
| | | | - Peter Mueller
- Institute of Soil Science, Center for Earth System Research and Sustainability, Universität Hamburg, Hamburg, Germany
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11
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Pang Z, Chen J, Wang T, Gao C, Li Z, Guo L, Xu J, Cheng Y. Linking Plant Secondary Metabolites and Plant Microbiomes: A Review. FRONTIERS IN PLANT SCIENCE 2021; 12:621276. [PMID: 33737943 PMCID: PMC7961088 DOI: 10.3389/fpls.2021.621276] [Citation(s) in RCA: 193] [Impact Index Per Article: 64.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 02/08/2021] [Indexed: 05/09/2023]
Abstract
Plant secondary metabolites (PSMs) play many roles including defense against pathogens, pests, and herbivores; response to environmental stresses, and mediating organismal interactions. Similarly, plant microbiomes participate in many of the above-mentioned processes directly or indirectly by regulating plant metabolism. Studies have shown that plants can influence their microbiome by secreting various metabolites and, in turn, the microbiome may also impact the metabolome of the host plant. However, not much is known about the communications between the interacting partners to impact their phenotypic changes. In this article, we review the patterns and potential underlying mechanisms of interactions between PSMs and plant microbiomes. We describe the recent developments in analytical approaches and methods in this field. The applications of these new methods and approaches have increased our understanding of the relationships between PSMs and plant microbiomes. Though the current studies have primarily focused on model organisms, the methods and results obtained so far should help future studies of agriculturally important plants and facilitate the development of methods to manipulate PSMs-microbiome interactions with predictive outcomes for sustainable crop productions.
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Affiliation(s)
- Zhiqiang Pang
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jia Chen
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Tuhong Wang
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Chunsheng Gao
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Zhimin Li
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Litao Guo
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Jianping Xu
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Yi Cheng
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
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12
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Ejiri M, Fukao T, Miyashita T, Shiono K. A barrier to radial oxygen loss helps the root system cope with waterlogging-induced hypoxia. BREEDING SCIENCE 2021; 71:40-50. [PMID: 33762875 PMCID: PMC7973497 DOI: 10.1270/jsbbs.20110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/14/2020] [Indexed: 05/04/2023]
Abstract
Internal aeration is crucial for root growth under waterlogged conditions. Many wetland plants have a structural barrier that impedes oxygen leakage from the basal part of roots called a radial oxygen loss (ROL) barrier. ROL barriers reduce the loss of oxygen transported via the aerenchyma to the root tips, enabling long-distance oxygen transport for cell respiration at the root tip. Because the root tip does not have an ROL barrier, some of the transferred oxygen is released into the waterlogged soil, where it oxidizes and detoxifies toxic substances (e.g., sulfate and Fe2+) around the root tip. ROL barriers are located at the outer part of roots (OPRs). Their main component is thought to be suberin. Suberin deposits may block the entry of potentially toxic compounds in highly reduced soils. The amount of ROL from the roots depends on the strength of the ROL barrier, the length of the roots, and environmental conditions, which causes spatiotemporal changes in the root system's oxidization pattern. We summarize recent achievements in understanding how ROL barrier formation is regulated and discuss opportunities for breeding waterlogging-tolerant crops.
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Affiliation(s)
- Masato Ejiri
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuoka-Kenjojima, Eiheiji, Fukui 910-1195,
Japan
| | - Takeshi Fukao
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuoka-Kenjojima, Eiheiji, Fukui 910-1195,
Japan
| | - Tomoki Miyashita
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuoka-Kenjojima, Eiheiji, Fukui 910-1195,
Japan
| | - Katsuhiro Shiono
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuoka-Kenjojima, Eiheiji, Fukui 910-1195,
Japan
- Corresponding author (e-mail: )
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13
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Merl T, Koren K. Visualizing NH 3 emission and the local O 2 and pH microenvironment of soil upon manure application using optical sensors. ENVIRONMENT INTERNATIONAL 2020; 144:106080. [PMID: 32890887 DOI: 10.1016/j.envint.2020.106080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/05/2020] [Accepted: 08/19/2020] [Indexed: 06/11/2023]
Abstract
The application of fertilizers and manure on fields is the largest source of ammonia (NH3) in the atmosphere.·NH3 emission from agriculture has negative environmental consequences and is largely controlled by the chemical microenvironment and the respective biological activity of the soil. While gas phase and bulk measurements can describe the emission on a large scale, those measurements fail to unravel the local processes and spatial heterogeneity at the soil air interface. We report a two dimensional (2D) imaging approach capable of visualizing three of the most important chemical parameters associated with NH3 emission from soil. Besides the released NH3 itself also O2 and pH microenvironments are imaged using reversible optodes in real-time with a spatial resolution of <100 µm. This combined optode approach utilizes a specifically developed NH3 optode with a limit of detection of 2.11 ppm and a large working range (0-1800 ppm) ideally suited for studying NH3 volatilization from soil. This NH3 optode will contribute to a better understanding of the driving factors for NH3 emission on a microscale and has the potential to become a valuable tool in studying NH3 dynamics.
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Affiliation(s)
- Theresa Merl
- Aarhus University Centre for Water Technology, Department of Biology, Section for Microbiology, Ny Munkegade 114, 8000 Aarhus C, Denmark; Graz University of Technology, Institute of Analytical Chemistry and Food Chemistry, Stremayrgasse 9/II, 8010 Graz, Austria
| | - Klaus Koren
- Aarhus University Centre for Water Technology, Department of Biology, Section for Microbiology, Ny Munkegade 114, 8000 Aarhus C, Denmark.
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14
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Cheng H, Wang YS, Li CD, Ye ZH, Muhammad S, Wu ML, Sun FL. Mixture of Pb, Zn and Cu on root permeability and radial oxygen loss in the mangrove Bruguiera gymnorrhiza. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:691-697. [PMID: 32472470 DOI: 10.1007/s10646-020-02234-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/13/2020] [Indexed: 06/11/2023]
Abstract
A short term pot trail was employed to evaluate the exposure of mixed heavy metals (Cu, Pb and Zn) on growth, radial oxygen loss (ROL) and root anatomy in Bruguiera gymnorrhiza. The possible function of BgC4H, a cytochrome P450 gene, on root lignification was also discussed. The exposures of mixed Cu, Pb and Zn directly reduce O2 leakage at root surface. The reduced ROL inhibited by heavy metals was mainly ascribed by the changes in root anatomical features, such as decreased root porosity together with increased lignification within the exodermis. BgC4H was found to be up-regulated after 0.5-day metal exposure, and remained higher transcript levels within 3-day metal exposure when compared to control roots. Besides, the inhibited photosynthesis may also result in less oxygen can be transported to the underground roots. In summary, the mangrove B. gymnorrhiza appeared to react to external mixed metal contaminants by developing a lignified and impermeable exodermis, and such a root barrier induced by mixed Cu, Pb and Zn appeared to be an adaptive response to block metal ions enters into the roots.
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Affiliation(s)
- Hao Cheng
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
- Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, 518121, China
- Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - You-Shao Wang
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
- Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, 518121, China.
- Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China.
| | - Chang-Da Li
- Marine and fisheries Development Research Center, Dongtou District, Wenzhou, 325009, China
| | - Zhi-Hong Ye
- State Key Laboratory for Bio-control, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Shafi Muhammad
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Mei-Lin Wu
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
- Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Fun-Lin Sun
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
- Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, 518121, China
- Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China
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15
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Scholz VV, Müller H, Koren K, Nielsen LP, Meckenstock RU. The rhizosphere of aquatic plants is a habitat for cable bacteria. FEMS Microbiol Ecol 2020; 95:5485638. [PMID: 31054245 PMCID: PMC6510695 DOI: 10.1093/femsec/fiz062] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/03/2019] [Indexed: 11/15/2022] Open
Abstract
Cable bacteria belonging to the family Desulfobulbaceae couple sulfide oxidation and oxygen reduction by long-distance electron transfer over centimeter distances in marine and freshwater sediments. In such habitats, aquatic plants can release oxygen into the rhizosphere. Hence, the rhizosphere constitutes an ideal habitat for cable bacteria, which have been reported on seagrass roots recently. Here, we employ experimental approaches to investigate activity, abundance, and spatial orientation of cable bacteria next to the roots of the freshwater plant Littorella uniflora. Fluorescence in situ hybridization (FISH), in combination with oxygen-sensitive planar optodes, demonstrated that cable bacteria densities are enriched at the oxic–anoxic transition zone next to roots compared to the bulk sediment in the same depth. Scanning electron microscopy showed cable bacteria along root hairs. Electric potential measurements showed a lateral electric field over centimeters from the roots, indicating cable bacteria activity. In addition, FISH revealed that cable bacteria were present in the rhizosphere of Oryza sativa (rice), Lobelia cardinalis and Salicornia europaea. Hence, the interaction of cable bacteria with aquatic plants of different growth forms and habitats indicates that the plant root–cable bacteria interaction might be a common property of aquatic plant rhizospheres.
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Affiliation(s)
- Vincent V Scholz
- Biofilm Centre, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany.,Center for Electromicrobiology, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark
| | - Hubert Müller
- Biofilm Centre, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany
| | - Klaus Koren
- Aarhus University Centre for Water Technology, Section for Microbiology, Department of Bioscience, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark
| | - Lars Peter Nielsen
- Center for Electromicrobiology, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark
| | - Rainer U Meckenstock
- Biofilm Centre, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany
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16
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de la Porte A, Schmidt R, Yergeau É, Constant P. A Gaseous Milieu: Extending the Boundaries of the Rhizosphere. Trends Microbiol 2020; 28:536-542. [PMID: 32544440 DOI: 10.1016/j.tim.2020.02.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/07/2019] [Accepted: 02/24/2020] [Indexed: 11/30/2022]
Abstract
Plant root activities shape microbial community functioning in the soil, making the rhizosphere the epicenter of soil biogeochemical processes. With this opinion article, we argue to rethink the rhizosphere boundaries: as gases can diffuse several centimeters away from the roots into the soil, the portion of soil influenced by root activities is larger than the strictly root-adhering soil. Indeed, gases are key drivers of biogeochemical processes due to their roles as energy sources or communication molecules, which has the potential to modify microbial community structure and functioning. In order to get a more holistic perspective on this key environment, we advocate for interdisciplinarity in rhizosphere research by combining knowledge of soluble compounds with gas dynamics.
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Affiliation(s)
- Anne de la Porte
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Laval, H7V 1B7, Canada; Quebec Center for Biodiversity Sciences (QCBS), Montreal, H3A 1B1, Canada
| | - Ruth Schmidt
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Laval, H7V 1B7, Canada; Quebec Center for Biodiversity Sciences (QCBS), Montreal, H3A 1B1, Canada.
| | - Étienne Yergeau
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Laval, H7V 1B7, Canada; Quebec Center for Biodiversity Sciences (QCBS), Montreal, H3A 1B1, Canada
| | - Philippe Constant
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Laval, H7V 1B7, Canada; Quebec Center for Biodiversity Sciences (QCBS), Montreal, H3A 1B1, Canada
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17
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Sugiyama A. The soybean rhizosphere: Metabolites, microbes, and beyond-A review. J Adv Res 2019; 19:67-73. [PMID: 31341671 PMCID: PMC6630087 DOI: 10.1016/j.jare.2019.03.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/15/2019] [Accepted: 03/16/2019] [Indexed: 11/17/2022] Open
Abstract
Rhizosphere microbial communities are important for plant health. Specialized metabolites in the rhizosphere influence the microbial communities. Isoflavones and saponins are major specialized metabolites secreted by soybean. Secretion is regulated developmentally and nutritionally. Possible links between specialized metabolites and microbial communities are highlighted.
The rhizosphere is the region close to a plant’s roots, where various interactions occur. Recent evidence indicates that plants influence rhizosphere microbial communities by secreting various metabolites and, in turn, the microbes influence the growth and health of the plants. Despite the importance of plant-derived metabolites in the rhizosphere, relatively little is known about their spatiotemporal distribution and dynamics. In addition to being an important crop, soybean (Glycine max) is a good model plant with which to study these rhizosphere interactions, because soybean plants have symbiotic relationships with rhizobia and arbuscular mycorrhizal fungi and secrete various specialized metabolites, such as isoflavones and saponins, into the soil. This review summarizes the characteristics of the soybean rhizosphere from the viewpoint of specialized metabolites and microbes and discusses future research perspectives. In sum, secretion of these metabolites is developmentally and nutritionally regulated and potentially alters the rhizosphere microbial communities.
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Affiliation(s)
- Akifumi Sugiyama
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji 611-0011, Japan
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18
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Han C, Ren J, Wang Z, Yang S, Ke F, Xu D, Xie X. Characterization of phosphorus availability in response to radial oxygen losses in the rhizosphere of Vallisneria spiralis. CHEMOSPHERE 2018; 208:740-748. [PMID: 29902758 DOI: 10.1016/j.chemosphere.2018.05.180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 05/23/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
The viewpoint that radial oxygen loss (ROL) of submerged macrophytes induces changes in redox conditions and the associated phosphorus (P) availability has been indirectly confirmed at larger spatial scales using conventional, destructive techniques. However, critical information about microniches has largely been overlooked due to the lack of satisfactory in situ mapping technologies. In this study, we deployed a recently developed hybrid sensor in the rhizosphere of Vallisneria spiralis (V. spiralis) during two vegetation periods to provide 2-D imaging of the spatiotemporal co-distribution of oxygen (O2) and P from a fixed observation point. Overall, the images of O2 and P showed a high degree of spatiotemporal heterogeneity throughout the rhizosphere at the sub-mm scale. A clear decrease in the P mobilization corresponded well to the steep O2 enhancement within a 2-mm-thick zone around younger V. spiralis root, indicating a significant coupling relationship between ROL and P availability. Surprisingly, despite significant diurnal shifts in ROL along the older V. spiralis roots, P availability did not fluctuate in a substantial part of the rhizosphere throughout the day; however, ROL increased the P immobilization significantly by changing the redox gradients at the outer rhizosphere. This study clearly demonstrates how continuous ROL of V. spiralis can play a major role in regulating P availability within the rhizosphere. The premise behind this statement is the discovery of how this continuous ROL can lead to the formation of three distinctive redox landscapes in the rooting sediment (oxic, suboxic, or anaerobic layers).
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Affiliation(s)
- Chao Han
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Jinghua Ren
- Geological Survey of Jiangsu Province, Nanjing, 210018, China
| | - Zhaode Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Shika Yang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Fan Ke
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Di Xu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Xianchuan Xie
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210093, China.
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19
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Pedersen O, Colmer TD, Garcia-Robledo E, Revsbech NP. CO2 and O2 dynamics in leaves of aquatic plants with C3 or CAM photosynthesis - application of a novel CO2 microsensor. ANNALS OF BOTANY 2018; 122:605-615. [PMID: 29893789 PMCID: PMC6153474 DOI: 10.1093/aob/mcy095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 05/07/2018] [Indexed: 05/29/2023]
Abstract
Background and Aims Leaf tissue CO2 partial pressure (pCO2) shows contrasting dynamics over a diurnal cycle in C3 and Crassulacean Acid Metabolism (CAM) plants. However, simultaneous and continuous monitoring of pCO2 and pO2 in C3 and CAM plants under the same conditions was lacking. Our aim was to use a new CO2 microsensor and an existing O2 microsensor for non-destructive measurements of leaf pCO2 and pO2 dynamics to compare a C3 and a CAM plant in an aquatic environment. Methods A new amperometric CO2 microsensor and an O2 microsensor elucidated with high temporal resolution the dynamics in leaf pCO2 and pO2 during light-dark cycles for C3Lobelia dortmanna and CAM Littorella uniflora aquatic plants. Underwater photosynthesis, dark respiration, tissue malate concentrations and sediment CO2 and O2 were also measured. Key Results During the dark period, for the C3 plant, pCO2 increased to approx. 3.5 kPa, whereas for the CAM plant CO2 was mostly below 0.05 kPa owing to CO2 sequestration into malate. Upon darkness, the CAM plant had an initial peak in pCO2 (approx. 0.16 kPa) which then declined to a quasi-steady state for several hours and then pCO2 increased towards the end of the dark period. The C3 plant became severely hypoxic late in the dark period, whereas the CAM plant with greater cuticle permeability did not. Upon illumination, leaf pCO2 declined and pO2 increased, although aspects of these dynamics also differed between the two plants. Conclusions The continuous measurements of pCO2 and pO2 highlighted the contrasting tissue gas compositions in submerged C3 and CAM plants. The CAM leaf pCO2 dynamics indicate an initial lag in CO2 sequestration to malate, which after several hours of malate synthesis then slows. Like the use of O2 microsensors to resolve questions related to plant aeration, deployment of the new CO2 microsensor will benefit plant ecophysiology research.
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Affiliation(s)
- Ole Pedersen
- Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, WA, Australia
| | - Timothy D Colmer
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, WA, Australia
| | - Emilio Garcia-Robledo
- Microbiology, Department of Bioscience, Aarhus University, Aarhus C, Denmark
- Ecology, Department of Biology, University of Cadiz, Poligono Rio San Pedro, Puerto Real, Cadiz, Spain
| | - Niels P Revsbech
- Microbiology, Department of Bioscience, Aarhus University, Aarhus C, Denmark
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20
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Rodeghiero M, Rubol S, Bellin A, Turco E, Molinatto G, Gianelle D, Pertot I. High Resolution Assessment of Spatio-Temporal Changes in O 2 Concentration in Root-Pathogen Interaction. Front Microbiol 2018; 9:1491. [PMID: 30026738 PMCID: PMC6041416 DOI: 10.3389/fmicb.2018.01491] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 06/15/2018] [Indexed: 01/19/2023] Open
Abstract
Fusarium wilt, caused by the fungus Fusarium oxysporum f. sp. lycopersici (Fol), is one of the most destructive soil-borne diseases of tomatoes. Infection takes place on the roots and the process starts with contact between the fungus and the roots hairs. To date, no detailed studies are available on metabolic activity in the early stages of the Fol and tomato root interaction. Spatial and temporal patterns of oxygen consumption could provide new insights into the dynamics of early colonization. Here, we combined planar optodes and spatial analysis to assess how tomato roots influence the metabolic activity and growth patterns of Fol. The results shows that the fungal metabolism, measured as oxygen consumption, increases within a few hours after the inoculation. Statistical analysis revealed that the fungus tends to growth toward the root, whereas, when the root is not present, the single elements of the fungus move with a Brownian motion (random). The combination of planar optodes and spatial analysis is a powerful new tool for assessing temporal and spatial dynamics in the early stages of root-pathogen interaction.
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Affiliation(s)
- Mirco Rodeghiero
- Sustainable Agro-Ecosystems and Bioresources Department, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
| | - Simonetta Rubol
- Energy Resources Engineering, Stanford University, Stanford, CA, United States
| | - Alberto Bellin
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.,Agriculture, Food and Environment Centre (C3A), University of Trento, San Michele all'Adige, Italy
| | - Elena Turco
- Sustainable Agro-Ecosystems and Bioresources Department, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
| | - Giulia Molinatto
- Department of Agricultural, Forest and Food Sciences, University of Turin, Turin, Italy
| | - Damiano Gianelle
- Sustainable Agro-Ecosystems and Bioresources Department, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
| | - Ilaria Pertot
- Sustainable Agro-Ecosystems and Bioresources Department, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy.,Agriculture, Food and Environment Centre (C3A), University of Trento, San Michele all'Adige, Italy
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21
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Koop-Jakobsen K, Mueller P, Meier RJ, Liebsch G, Jensen K. Plant-Sediment Interactions in Salt Marshes - An Optode Imaging Study of O 2, pH, and CO 2 Gradients in the Rhizosphere. FRONTIERS IN PLANT SCIENCE 2018; 9:541. [PMID: 29774037 PMCID: PMC5943611 DOI: 10.3389/fpls.2018.00541] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 04/06/2018] [Indexed: 05/26/2023]
Abstract
In many wetland plants, belowground transport of O2 via aerenchyma tissue and subsequent O2 loss across root surfaces generates small oxic root zones at depth in the rhizosphere with important consequences for carbon and nutrient cycling. This study demonstrates how roots of the intertidal salt-marsh plant Spartina anglica affect not only O2, but also pH and CO2 dynamics, resulting in distinct gradients of O2, pH, and CO2 in the rhizosphere. A novel planar optode system (VisiSens TD®, PreSens GmbH) was used for taking high-resolution 2D-images of the O2, pH, and CO2 distribution around roots during alternating light-dark cycles. Belowground sediment oxygenation was detected in the immediate vicinity of the roots, resulting in oxic root zones with a 1.7 mm radius from the root surface. CO2 accumulated around the roots, reaching a concentration up to threefold higher than the background concentration, and generally affected a larger area within a radius of 12.6 mm from the root surface. This contributed to a lowering of pH by 0.6 units around the roots. The O2, pH, and CO2 distribution was recorded on the same individual roots over diurnal light cycles in order to investigate the interlinkage between sediment oxygenation and CO2 and pH patterns. In the rhizosphere, oxic root zones showed higher oxygen concentrations during illumination of the aboveground biomass. In darkness, intraspecific differences were observed, where some plants maintained oxic root zones in darkness, while others did not. However, the temporal variation in sediment oxygenation was not reflected in the temporal variations of pH and CO2 around the roots, which were unaffected by changing light conditions at all times. This demonstrates that plant-mediated sediment oxygenation fueling microbial decomposition and chemical oxidation has limited impact on the dynamics of pH and CO2 in S. anglica rhizospheres, which may in turn be controlled by other processes such as root respiration and root exudation.
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Affiliation(s)
- Ketil Koop-Jakobsen
- MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Peter Mueller
- Applied Plant Ecology, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
| | | | | | - Kai Jensen
- Applied Plant Ecology, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
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