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Deep-rooted perennial crops differ in capacity to stabilize C inputs in deep soil layers. Sci Rep 2022; 12:5952. [PMID: 35396458 PMCID: PMC8993804 DOI: 10.1038/s41598-022-09737-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 03/17/2022] [Indexed: 01/04/2023] Open
Abstract
Comprehensive climate change mitigation necessitates soil carbon (C) storage in cultivated terrestrial ecosystems. Deep-rooted perennial crops may help to turn agricultural soils into efficient C sinks, especially in deeper soil layers. Here, we compared C allocation and potential stabilization to 150 cm depth from two functionally distinct deep-rooted perennials, i.e., lucerne (Medicago sativa L.) and intermediate wheatgrass (kernza; Thinopyrum intermedium), representing legume and non-legume crops, respectively. Belowground C input and stabilization was decoupled from nitrogen (N) fertilizer rate in kernza (100 and 200 kg mineral N ha−1), with no direct link between increasing mineral N fertilization, rhizodeposited C, and microbial C stabilization. Further, both crops displayed a high ability to bring C to deeper soil layers and remarkably, the N2-fixing lucerne showed greater potential to induce microbial C stabilization than the non-legume kernza. Lucerne stimulated greater microbial biomass and abundance of N cycling genes in rhizosphere soil, likely linked to greater amino acid rhizodeposition, hence underlining the importance of coupled C and N for microbial C stabilization efficiency. Inclusion of legumes in perennial cropping systems is not only key for improved productivity at low fertilizer N inputs, but also appears critical for enhancing soil C stabilization, in particular in N limited deep subsoils.
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Garcia-Lemos AM, Großkinsky DK, Saleem Akhtar S, Nicolaisen MH, Roitsch T, Nybroe O, Veierskov B. Identification of Root-Associated Bacteria That Influence Plant Physiology, Increase Seed Germination, or Promote Growth of the Christmas Tree Species Abies nordmanniana. Front Microbiol 2020; 11:566613. [PMID: 33281762 PMCID: PMC7705201 DOI: 10.3389/fmicb.2020.566613] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/27/2020] [Indexed: 12/03/2022] Open
Abstract
Abies nordmanniana is used for Christmas tree production but poor seed germination and slow growth represent challenges for the growers. We addressed the plant growth promoting potential of root-associated bacteria isolated from A. nordmanniana. Laboratory screenings of a bacterial strain collection yielded several Bacillus and Paenibacillus strains that improved seed germination and produced indole-3-acetic acid. The impact of three of these strains on seed germination, plant growth and growth-related physiological parameters was then determined in greenhouse and field trials after seed inoculation, and their persistence was assessed by 16S rRNA gene-targeted bacterial community analysis. Two strains showed distinct and significant effects. Bacillus sp. s50 enhanced seed germination in the greenhouse but did not promote shoot or root growth. In accordance, this strain did not increase the level of soluble hexoses needed for plant growth but increased the level of storage carbohydrates. Moreover, strain s50 increased glutathione reductase and glutathione-S-transferase activities in the plant, which may indicate induction of systemic resistance during the early phase of plant development, as the strain showed poor persistence in the root samples (rhizosphere soil plus root tissue). Paenibacillus sp. s37 increased plant root growth, especially by inducing secondary root formation, under in greenhouse conditions, where it showed high persistence in the root samples. Under these conditions, it further it increased the level of soluble carbohydrates in shoots, and the levels of starch and non-structural carbohydrates in roots, stem and shoots. Moreover, it increased the chlorophyll level in the field trial. These findings indicate that this strain improves plant growth and vigor through effects on photosynthesis and plant carbohydrate reservoirs. The current results show that the two strains s37 and s50 could be considered for growth promotion programs of A. nordmanniana in greenhouse nurseries, and even under field conditions.
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Affiliation(s)
- Adriana M Garcia-Lemos
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Dominik K Großkinsky
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark.,Bioresources Unit, Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Tulln an der Donau, Austria
| | - Saqib Saleem Akhtar
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Mette Haubjerg Nicolaisen
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Thomas Roitsch
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark.,Department of Adaptive Biotechnologies, Global Change Research Institute, Brno, Czechia
| | - Ole Nybroe
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Bjarke Veierskov
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
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Kämpfer P, Glaeser SP, McInroy JA, Xu J, Busse HJ, Clermont D, Criscuolo A. Flavobacterium panici sp. nov. isolated from the rhizosphere of the switchgrass Panicum virgatum. Int J Syst Evol Microbiol 2020; 70:5824-5831. [PMID: 33034547 DOI: 10.1099/ijsem.0.004482] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A Gram-staining-negative non endospore-forming strain, PXU-55T, was isolated from the rhizosphere of the switchgrass Panicum virgatum and studied in detail to determine its taxonomic position. The results of 16S rRNA gene sequence analysis indicated that the isolate represented a member of the genus Flavobacterium. The isolate shared highest 16S rRNA gene sequence similarities with the type strains of Flavobacterium chungangense (98.78 %) and Flavobacterium chilense (98.64 %). The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (isDDH) values between the PXU-55T genome assembly and the ones of the most closely related type strains of species of the genus Flavobacterium were 87.3 and 31.9% (Flavobacterium defluvii), and 86.1 and 29.9% (Flavobacterium johnsoniae). Menaquinone MK-6 was the major respiratory quinone. As major polar lipids, phosphatidylethanolamine, an ornithine lipid and the unidentified polar lipids L2, L3 and L4 lacking a functional group were found. Moderate to minor amounts of another ornithine lipid, the unidentified lipid L1 and a glycolipid were present, as well. The major polyamine is sym-homospermidine. The fatty acid profiles contained major amounts of iso-C15:0, iso-C15:0 3-OH, iso-C17:0 3-OH, C15:0, summed feature 3 (C16:1ω7c and/or iso-C15:0 2-OH) and various hydroxylated fatty acids in smaller amounts, among them iso C16:0 3-OH, C16:0 3-OH and C15:0 3-OH, which supported the classification of the isolate as a member of the genus Flavobacterium. Physiological and biochemical characterisation and ANI calculations with the type strains of the most closely related species allowed a clear phenotypic and genotypic differentiation of the strain. For this reason, we propose that strain PXU-55T (=CIP 111646T=CCM 8914T) represents a novel species with the name Flavobacterium panici sp. nov.
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Affiliation(s)
- Peter Kämpfer
- Institut für Angewandte Mikrobiologie, Justus-Liebig-Universität Giessen, D-35392 Giessen, Germany
| | - S P Glaeser
- Institut für Angewandte Mikrobiologie, Justus-Liebig-Universität Giessen, D-35392 Giessen, Germany
| | - John A McInroy
- Department of Entomology and Plant Pathology, Auburn University, Alabama, USA
| | - Jia Xu
- Department of Entomology and Plant Pathology, Auburn University, Alabama, USA
| | - Hans-Jürgen Busse
- Institut für Mikrobiologie, Veterinärmedizinische Universität, A-1210 Wien, Austria
| | | | - Alexis Criscuolo
- Hub de Bioinformatique et Biostatistique - Département Biologie Computationnelle, Institut Pasteur, USR 3756 CNRS, Paris, France
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Cavalieri A, Bak F, Garcia-Lemos AM, Weiner J, Nicolaisen MH, Nybroe O. Effects of Intra- and Interspecific Plant Density on Rhizosphere Bacterial Communities. Front Microbiol 2020; 11:1045. [PMID: 32528445 PMCID: PMC7264394 DOI: 10.3389/fmicb.2020.01045] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/27/2020] [Indexed: 11/13/2022] Open
Abstract
There have been very few studies on the effects of plant competition on the rhizosphere bacterial community. To investigate the impacts of intra- and interspecific plant competition, we analyzed the responses of rhizosphere bacterial communities to plant density as determined by 16S rRNA gene targeted sequencing. We included five weedy plant species growing in field soil in monocultures and mixed cultures at three densities in a greenhouse experiment. The rhizosphere bacterial community of each species changed more with density in a mixture of all five plant species than in monocultures, so intra- and interspecific plant competition had different effects on the bacterial community. For the dominant plant competitor, Centaurea cyanus, neither intra- nor interspecific competition had major effects on the composition of its rhizosphere bacterial communities. In contrast, the bacterial communities of the weakest competitor, Trifolium repens, were affected differently by intra- and interspecific competition. During increasing intraspecific competition T. repens maintained a highly specialized bacterial community dominated by Rhizobium; while during interspecific competition, the relative abundance of Rhizobium declined while other nitrogen fixing and potentially plant growth promoting taxa became more abundant. Contrary to previous observations made for soil microbial communities, the bacterial rhizosphere community of the weakest competitor did not become more similar to that of the dominant species. Thus, the process of competition, as well as the plant species themselves, determined the rhizosphere bacterial community. Our results emphasize the role of plant-plant interactions for rhizosphere bacterial communities. These effects may feedback to affect plant-plant interactions, and this is an important hypothesis for future research.
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Affiliation(s)
- Andrea Cavalieri
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Frederik Bak
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Adriana M Garcia-Lemos
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Jacob Weiner
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | - Ole Nybroe
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
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Garcia-Lemos AM, Großkinsky DK, Saleem Akhtar S, Nicolaisen MH, Roitsch T, Nybroe O, Veierskov B. Identification of Root-Associated Bacteria That Influence Plant Physiology, Increase Seed Germination, or Promote Growth of the Christmas Tree Species Abies nordmanniana. Front Microbiol 2020. [PMID: 33281762 DOI: 10.3389/fmicb.2020.566613)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
Abstract
Abies nordmanniana is used for Christmas tree production but poor seed germination and slow growth represent challenges for the growers. We addressed the plant growth promoting potential of root-associated bacteria isolated from A. nordmanniana. Laboratory screenings of a bacterial strain collection yielded several Bacillus and Paenibacillus strains that improved seed germination and produced indole-3-acetic acid. The impact of three of these strains on seed germination, plant growth and growth-related physiological parameters was then determined in greenhouse and field trials after seed inoculation, and their persistence was assessed by 16S rRNA gene-targeted bacterial community analysis. Two strains showed distinct and significant effects. Bacillus sp. s50 enhanced seed germination in the greenhouse but did not promote shoot or root growth. In accordance, this strain did not increase the level of soluble hexoses needed for plant growth but increased the level of storage carbohydrates. Moreover, strain s50 increased glutathione reductase and glutathione-S-transferase activities in the plant, which may indicate induction of systemic resistance during the early phase of plant development, as the strain showed poor persistence in the root samples (rhizosphere soil plus root tissue). Paenibacillus sp. s37 increased plant root growth, especially by inducing secondary root formation, under in greenhouse conditions, where it showed high persistence in the root samples. Under these conditions, it further it increased the level of soluble carbohydrates in shoots, and the levels of starch and non-structural carbohydrates in roots, stem and shoots. Moreover, it increased the chlorophyll level in the field trial. These findings indicate that this strain improves plant growth and vigor through effects on photosynthesis and plant carbohydrate reservoirs. The current results show that the two strains s37 and s50 could be considered for growth promotion programs of A. nordmanniana in greenhouse nurseries, and even under field conditions.
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Affiliation(s)
- Adriana M Garcia-Lemos
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Dominik K Großkinsky
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
- Bioresources Unit, Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Tulln an der Donau, Austria
| | - Saqib Saleem Akhtar
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Mette Haubjerg Nicolaisen
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Thomas Roitsch
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
- Department of Adaptive Biotechnologies, Global Change Research Institute, Brno, Czechia
| | - Ole Nybroe
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Bjarke Veierskov
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
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