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Ishak S, Rondeau-Leclaire J, Faticov M, Roy S, Laforest-Lapointe I. Boreal moss-microbe interactions are revealed through metagenome assembly of novel bacterial species. Sci Rep 2024; 14:22168. [PMID: 39333734 PMCID: PMC11437008 DOI: 10.1038/s41598-024-73045-z] [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: 06/17/2024] [Accepted: 09/12/2024] [Indexed: 09/30/2024] Open
Abstract
Moss-microbe interactions contribute to ecosystem processes in boreal forests. Yet, how host-specific characteristics and the environment drive the composition and metabolic potential of moss microbiomes is still poorly understood. In this study, we use shotgun metagenomics to identify the taxonomy and metabolic potential of the bacteria of four moss species of the boreal forests of Northern Québec, Canada. To characterize moss bacterial community composition and diversity, we assembled the genomes of 110 potentially novel bacterial species. Our results highlight that moss genus, species, gametophyte section, and to a lesser extent soil pH and soil temperature, drive moss-associated bacterial community composition and diversity. In the brown gametophyte section, two Stigonema spp. showed partial pathway completeness for photosynthesis and nitrogen fixation, while all brown-associated Hyphomicrobiales had complete assimilatory nitrate reduction pathways and many nearly complete carbon fixation pathways. Several brown-associated species showed partial to complete pathways for coenzyme M and F420 biosynthesis, important for methane metabolism. In addition, green-associated Hyphomicrobiales (Methylobacteria spp.) displayed potential for the anoxygenic photosystem II pathway. Overall, our findings demonstrate how host-specific characteristics and environmental factors shape the composition and metabolic potential of moss bacteria, highlighting their roles in carbon fixation, nitrogen cycling, and methane metabolism in boreal forests.
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Affiliation(s)
- Sarah Ishak
- Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Centre d'Étude de la Forêt, Université du Québec à Montréal, Montréal, QC, Canada.
| | | | - Maria Faticov
- Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
- Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, Canada
- Centre d'Étude de la Forêt, Université du Québec à Montréal, Montréal, QC, Canada
| | - Sébastien Roy
- Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
- Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Isabelle Laforest-Lapointe
- Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Centre d'Étude de la Forêt, Université du Québec à Montréal, Montréal, QC, Canada.
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2
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Lett S, Christiansen CT, Dorrepaal E, Michelsen A. Moss species and precipitation mediate experimental warming stimulation of growing season N 2 fixation in subarctic tundra. GLOBAL CHANGE BIOLOGY 2024; 30:e17401. [PMID: 39041207 DOI: 10.1111/gcb.17401] [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: 05/27/2024] [Accepted: 06/09/2024] [Indexed: 07/24/2024]
Abstract
Climate change in high latitude regions leads to both higher temperatures and more precipitation but their combined effects on terrestrial ecosystem processes are poorly understood. In nitrogen (N) limited and often moss-dominated tundra and boreal ecosystems, moss-associated N2 fixation is an important process that provides new N. We tested whether high mean annual precipitation enhanced experimental warming effects on growing season N2 fixation in three common arctic-boreal moss species adapted to different moisture conditions and evaluated their N contribution to the landscape level. We measured in situ N2 fixation rates in Hylocomium splendens, Pleurozium schreberi and Sphagnum spp. from June to September in subarctic tundra in Sweden. We exposed mosses occurring along a natural precipitation gradient (mean annual precipitation: 571-1155 mm) to 8 years of experimental summer warming using open-top chambers before our measurements. We modelled species-specific seasonal N input to the ecosystem at the colony and landscape level. Higher mean annual precipitation clearly increased N2 fixation, especially during peak growing season and in feather mosses. For Sphagnum-associated N2 fixation, high mean annual precipitation reversed a small negative warming response. By contrast, in the dry-adapted feather moss species higher mean annual precipitation led to negative warming effects. Modelled total growing season N inputs for Sphagnum spp. colonies were two to three times that of feather mosses at an area basis. However, at the landscape level where feather mosses were more abundant, they contributed 50% more N than Sphagnum. The discrepancy between modelled estimates of species-specific N input via N2 fixation at the moss core versus ecosystem scale, exemplify how moss cover is essential for evaluating impact of altered N2 fixation. Importantly, combined effects of warming and higher mean annual precipitation may not lead to similar responses across moss species, which could affect moss fitness and their abilities to buffer environmental changes.
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Affiliation(s)
- Signe Lett
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Center for Permafrost (CENPERM), University of Copenhagen, Copenhagen, Denmark
| | - Casper T Christiansen
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Center for Permafrost (CENPERM), University of Copenhagen, Copenhagen, Denmark
| | - Ellen Dorrepaal
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Anders Michelsen
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Center for Permafrost (CENPERM), University of Copenhagen, Copenhagen, Denmark
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3
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Alvarenga DO, Priemé A, Rousk K. The Feather Moss Hylocomium splendens Affects the Transcriptional Profile of a Symbiotic Cyanobacterium in Relation to Acquisition and Turnover of Key Nutrients. MICROBIAL ECOLOGY 2024; 87:49. [PMID: 38427046 PMCID: PMC10907420 DOI: 10.1007/s00248-024-02363-6] [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: 11/10/2023] [Accepted: 02/21/2024] [Indexed: 03/02/2024]
Abstract
Moss-cyanobacteria symbioses were proposed to be based on nutrient exchange, with hosts providing C and S while bacteria provide N, but we still lack understanding of the underlying molecular mechanisms of their interactions. We investigated how contact between the ubiquitous moss Hylocomium splendens and its cyanobiont affects nutrient-related gene expression of both partners. We isolated a cyanobacterium from H. splendens and co-incubated it with washed H. splendens shoots. Cyanobacterium and moss were also incubated separately. After 1 week, we performed acetylene reduction assays to estimate N2 fixation and RNAseq to evaluate metatranscriptomes. Genes related to N2 fixation and the biosynthesis of several amino acids were up-regulated in the cyanobiont when hosted by the moss. However, S-uptake and the biosynthesis of the S-containing amino acids methionine and cysteine were down-regulated in the cyanobiont while the degradation of selenocysteine was up-regulated. In contrast, the number of differentially expressed genes in the moss was much lower, and almost no transcripts related to nutrient metabolism were affected. It is possible that, at least during the early stage of this symbiosis, the cyanobiont receives few if any nutrients from the host in return for N, suggesting that moss-cyanobacteria symbioses encompass relationships that are more plastic than a constant mutualist flow of nutrients.
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Affiliation(s)
- Danillo Oliveira Alvarenga
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.
- Center for Volatile Interactions, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.
| | - Anders Priemé
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
- Center for Volatile Interactions, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
| | - Kathrin Rousk
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
- Center for Volatile Interactions, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
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4
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Groß C, Hossen S, Dittrich S, Knorr KH, Borken W, Noll M. Biological nitrogen fixation, diversity and community structure of diazotrophs in two mosses in 25 temperate forests. Environ Microbiol 2024; 26:e16555. [PMID: 38148519 DOI: 10.1111/1462-2920.16555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 11/27/2023] [Indexed: 12/28/2023]
Abstract
Many moss species are associated with nitrogen (N)-fixing bacteria (diazotrophs) that support the N supply of mosses. Our knowledge relates primarily to pristine ecosystems with low atmospheric N input, but knowledge of biological N fixation (BNF) and diazotrophic communities in mosses in temperate forests with high N deposition is limited. We measured BNF rates using the direct stable isotope method and studied the total and potentially active diazotrophic communities in two abundant mosses, Brachythecium rutabulum and Hypnum cupressiforme, both growing on lying deadwood trunks in 25 temperate forest sites. BNF rates in both mosses were similar to those observed in moss species of pristine ecosystems. H. cupressiforme fixed three times more N2 and exhibited lower diazotrophic richness than B. rutabulum. Frankia was the most prominent diazotroph followed by cyanobacteria Nostoc. Manganese, iron, and molybdenum contents in mosses were positively correlated with BNF and diazotrophic communities. Frankia maintained high BNF rates in H. cupressiforme and B. rutabulum even under high chronic N deposition in Central European forests. Moss N concentration and 15 N abundance indicate a rather minor contribution of BNF to the N nutrition of these mosses.
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Affiliation(s)
- Christina Groß
- Department of Soil Ecology, University of Bayreuth, Bayreuth, Germany
| | - Shakhawat Hossen
- Institute for Bioanalysis, Coburg University of Applied Sciences and Arts, Coburg, Germany
| | - Sebastian Dittrich
- Biodiversity and Conservation, Technical University of Dresden, Tharandt, Germany
| | - Klaus-Holger Knorr
- Institute of Landscape Ecology, Ecohydrology and Biogeochemistry Group, University of Münster, Münster, Germany
| | - Werner Borken
- Department of Soil Ecology, University of Bayreuth, Bayreuth, Germany
| | - Matthias Noll
- Institute for Bioanalysis, Coburg University of Applied Sciences and Arts, Coburg, Germany
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5
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Álvarez C, Jiménez-Ríos L, Iniesta-Pallarés M, Jurado-Flores A, Molina-Heredia FP, Ng CKY, Mariscal V. Symbiosis between cyanobacteria and plants: from molecular studies to agronomic applications. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6145-6157. [PMID: 37422707 PMCID: PMC10575698 DOI: 10.1093/jxb/erad261] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/06/2023] [Indexed: 07/10/2023]
Abstract
Nitrogen-fixing cyanobacteria from the order Nostocales are able to establish symbiotic relationships with diverse plant species. They are promiscuous symbionts, as the same strain of cyanobacterium is able to form symbiotic biological nitrogen-fixing relationships with different plants species. This review will focus on the different types of cyanobacterial-plant associations, both endophytic and epiphytic, and provide insights from a structural viewpoint, as well as our current understanding of the mechanisms involved in the symbiotic crosstalk. In all these symbioses, the benefit for the plant is clear; it obtains from the cyanobacterium fixed nitrogen and other bioactive compounds, such as phytohormones, polysaccharides, siderophores, or vitamins, leading to enhanced plant growth and productivity. Additionally, there is increasing use of different cyanobacterial species as bio-inoculants for biological nitrogen fixation to improve soil fertility and crop production, thus providing an eco-friendly, alternative, and sustainable approach to reduce the over-reliance on synthetic chemical fertilizers.
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Affiliation(s)
- Consolación Álvarez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Lucía Jiménez-Ríos
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Macarena Iniesta-Pallarés
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Ana Jurado-Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Fernando P Molina-Heredia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Carl K Y Ng
- UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin, Ireland
- UCD Centre for Plant Science, University College Dublin, Belfield, Dublin, Ireland
- UCD Earth Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
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6
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Frangedakis E, Marron AO, Waller M, Neubauer A, Tse SW, Yue Y, Ruaud S, Waser L, Sakakibara K, Szövényi P. What can hornworts teach us? FRONTIERS IN PLANT SCIENCE 2023; 14:1108027. [PMID: 36968370 PMCID: PMC10030945 DOI: 10.3389/fpls.2023.1108027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
The hornworts are a small group of land plants, consisting of only 11 families and approximately 220 species. Despite their small size as a group, their phylogenetic position and unique biology are of great importance. Hornworts, together with mosses and liverworts, form the monophyletic group of bryophytes that is sister to all other land plants (Tracheophytes). It is only recently that hornworts became amenable to experimental investigation with the establishment of Anthoceros agrestis as a model system. In this perspective, we summarize the recent advances in the development of A. agrestis as an experimental system and compare it with other plant model systems. We also discuss how A. agrestis can help to further research in comparative developmental studies across land plants and to solve key questions of plant biology associated with the colonization of the terrestrial environment. Finally, we explore the significance of A. agrestis in crop improvement and synthetic biology applications in general.
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Affiliation(s)
| | - Alan O. Marron
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Manuel Waller
- Department of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
- Zurich-Basel Plant Science Center, Zurich, Switzerland
| | - Anna Neubauer
- Department of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
- Zurich-Basel Plant Science Center, Zurich, Switzerland
| | - Sze Wai Tse
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Yuling Yue
- Department of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
- Zurich-Basel Plant Science Center, Zurich, Switzerland
| | - Stephanie Ruaud
- Department of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
- Zurich-Basel Plant Science Center, Zurich, Switzerland
| | - Lucas Waser
- Department of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
- Zurich-Basel Plant Science Center, Zurich, Switzerland
- Department of Plant and Microbial Biology, University of Zürich, Zurich, Switzerland
| | | | - Péter Szövényi
- Department of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
- Zurich-Basel Plant Science Center, Zurich, Switzerland
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7
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Kubota M, Matsushita N, Nakamura T, Fukuda K. Nitrogen fixation and nifH gene diversity in cyanobacteria living on feather mosses in a subalpine forest of Mt. Fuji. Oecologia 2023; 201:749-760. [PMID: 36808304 PMCID: PMC10038973 DOI: 10.1007/s00442-023-05334-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/07/2023] [Indexed: 02/23/2023]
Abstract
In the boreal forests, feather mosses such as Hylocomium splendens and Pleurozium schreberi are colonized by cyanobacteria, which provide large amounts of nitrogen to forest ecosystems through nitrogen fixation. Although these feather mosses are also ubiquitous in subalpine forests of East Asia, little is known regarding their associated cyanobacteria and their ability to fix nitrogen. In this study, we investigated (1) whether cyanobacteria co-exist and fix nitrogen in the two species of feather mosses that cover the ground surface in a subalpine forest of Mt. Fuji, (2) whether cyanobacteria belonging to a common cluster with boreal forests are found in feather mosses in Mt. Fuji, and (3) whether moss-associated nitrogen fixation rates differed among moss growing substrates, canopy openness, and moss nitrogen concentrations in the same forest area. Our results showed that cyanobacteria colonized feather mosses in the subalpine forests of Mt. Fuji and acetylene reduction rates as an index of nitrogen fixation tended to be higher in H. splendens than in P. schreberi. Based on analysis of the nifH gene, 43 bacterial operational taxonomic units (OTUs) were identified, 28 of which represented cyanobacteria. Among the five clusters of cyanobacteria classified based on their nifH gene and identified in northern Europe, four (Nostoc cluster I, Nostoc cluster II, Stigonema cluster, and nifH2 cluster) were also found at Mt. Fuji. The acetylene reduction rate differed depending on the moss growing substrate and the total nitrogen concentration of moss shoots, and a strong negative correlation was observed with the total nitrogen concentration.
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Affiliation(s)
- Masayuki Kubota
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan.
| | - Norihisa Matsushita
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan
| | - Toshihiko Nakamura
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan
| | - Kenji Fukuda
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan
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8
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Cleveland CC, Reis CRG, Perakis SS, Dynarski KA, Batterman SA, Crews TE, Gei M, Gundale MJ, Menge DNL, Peoples MB, Reed SC, Salmon VG, Soper FM, Taylor BN, Turner MG, Wurzburger N. Exploring the Role of Cryptic Nitrogen Fixers in Terrestrial Ecosystems: A Frontier in Nitrogen Cycling Research. Ecosystems 2022. [DOI: 10.1007/s10021-022-00804-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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Renaudin M, Laforest-Lapointe I, Bellenger JP. Unraveling global and diazotrophic bacteriomes of boreal forest floor feather mosses and their environmental drivers at the ecosystem and at the plant scale in North America. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 837:155761. [PMID: 35533858 DOI: 10.1016/j.scitotenv.2022.155761] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/29/2022] [Accepted: 05/03/2022] [Indexed: 06/14/2023]
Abstract
Feather mosses are abundant cryptogams of the boreal forest floor and shelter a broad diversity of bacteria who have important ecological functions (e.g., decomposition, nutrient cycling). In particular, nitrogen (N2-) fixation performed by feather moss-associated diazotrophs constitutes an important entry of nitrogen in the boreal forest ecosystem. However, the composition of the feather moss bacteriome and its environmental drivers are still unclear. Using cDNA amplicon sequencing of the 16S rRNA and nifH genes and cyanobacterial biomass quantification, we explored the active global and diazotrophic bacterial communities of two dominant feather moss species (i) at the ecosystem scale, along a 500-km climatic and nutrient deposition gradient in the North American boreal forest, and (ii) at the plant scale, along the moss shoot senescence gradient. We found that cyanobacteria were major actors of the feather moss bacteriome, accounting for 33% of global bacterial communities and 65% of diazotrophic communities, and that several cyanobacterial and methanotrophic genera were contributing to N2-fixation. Moreover, we showed that bacteria were occupying ecological niches along the moss shoot, with phototrophs being dominant in the apical part and methanotrophs being dominant in the basal part. Finally, climate (temperature, precipitation), environmental variables (moss species, month, tree density) and nutrients (nitrogen, phosphorus, molybdenum, vanadium, iron) strongly shaped global and diazotrophic bacteriomes. In summary, this work presents evidence that the feather moss bacteriome plays crucial roles in supporting moss growth, health, and decomposition, as well as in the boreal forest carbon and nitrogen cycles. This study also highlights the substantial effects of climate and nutrients on the feather moss bacteriome, suggesting the importance of understanding the impacts of global change on moss-associated bacterial growth and activity.
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Affiliation(s)
- Marie Renaudin
- Centre Sève, Département de Chimie, Université de Sherbrooke, J1K 2R1 Sherbrooke, QC, Canada.
| | | | - Jean-Philippe Bellenger
- Centre Sève, Département de Chimie, Université de Sherbrooke, J1K 2R1 Sherbrooke, QC, Canada.
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10
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Rousk K. Biotic and abiotic controls of nitrogen fixation in cyanobacteria-moss associations. THE NEW PHYTOLOGIST 2022; 235:1330-1335. [PMID: 35687087 DOI: 10.1111/nph.18264] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Most mosses are colonized by nitrogen (N)-fixing cyanobacteria. This discovery is relatively recent, which can explain the large knowledge gaps the field is now tackling. For instance, while we have a good understanding of the abiotic controls (e.g. nutrient availability, increased temperature), we still do not know much about the biotic controls of N2 fixation in mosses. I propose here that we should endeavour to position moss-cyanobacteria associations along the mutualism-parasitism continuum under varying abiotic conditions (e.g. nutrient availability). This would finally unravel the nature of the relationship between the partners and will be a big leap in our understanding of the evolution of plant-bacteria interactions using moss-cyanobacteria associations as a model system.
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Affiliation(s)
- Kathrin Rousk
- Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
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11
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Alvarenga DO, Elmdam IV, Timm AB, Rousk K. Chemical Stimulation of Heterocyte Differentiation by the Feather Moss Hylocomium splendens: a Potential New Step in Plant-Cyanobacteria Symbioses. MICROBIAL ECOLOGY 2022:10.1007/s00248-022-02075-9. [PMID: 35859069 DOI: 10.1007/s00248-022-02075-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 07/05/2022] [Indexed: 06/15/2023]
Abstract
Cyanobacteria associated with mosses play a key role in the nitrogen (N) cycle in unpolluted ecosystems. Mosses have been found to release molecules that induce morphophysiological changes in epiphytic cyanobionts. Nevertheless, the extent of moss influence on these microorganisms remains unknown. To evaluate how mosses or their metabolites influence N2 fixation rates by cyanobacteria, we assessed the nitrogenase activity, heterocyte frequency and biomass of a cyanobacterial strain isolated from the feather moss Hylocomium splendens and a non-symbiotic strain when they were either growing by themselves, together with H. splendens or exposed to H. splendens water, acetone, ethanol, or isopropanol extracts. The same cyanobacterial strains were added to another moss (Taxiphyllum barbieri) and a liverwort (Monosolenium tenerum) to assess if these bryophytes affect N2 fixation differently. Although no significant increases in nitrogenase activity by the cyanobacteria were observed when in contact with H. splendens shoots, both the symbiotic and non-symbiotic cyanobacteria increased nitrogenase activity as well as heterocyte frequency significantly upon exposure to H. splendens ethanol extracts. Contact with T. barbieri shoots, on the other hand, did lead to increases in nitrogenase activity, indicating low host-specificity to cyanobacterial activity. These findings suggest that H. splendens produces heterocyte-differentiating factors (HDFs) that are capable of stimulating cyanobacterial N2 fixation regardless of symbiotic competency. Based on previous knowledge about the chemical ecology and dynamics of moss-cyanobacteria interactions, we speculate that HDF expression by the host takes place in a hypothetical new step occurring after plant colonization and the repression of hormogonia.
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Affiliation(s)
- Danillo Oliveira Alvarenga
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.
- Centre for Permafrost, University of Copenhagen, Øster Voldgade 10, 1350, Copenhagen, Denmark.
| | - Isabella Vendel Elmdam
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
| | | | - Kathrin Rousk
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
- Centre for Permafrost, University of Copenhagen, Øster Voldgade 10, 1350, Copenhagen, Denmark
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12
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Rodríguez-Rodríguez JC, Bergeron Y, Kembel SW, Fenton NJ. Dominance of coniferous and broadleaved trees drives bacterial associations with boreal feather mosses. Environ Microbiol 2022; 24:3517-3528. [PMID: 35416394 DOI: 10.1111/1462-2920.16013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/09/2022] [Accepted: 04/09/2022] [Indexed: 12/01/2022]
Abstract
The composition of ecologically important moss-associated bacterial communities seems to be mainly driven by host species but may also be shaped by environmental conditions related with tree dominance. The moss phyllosphere has been studied in coniferous forests while broadleaf forests remain understudied. To determine if host species or environmental conditions defined by tree dominance drives the bacterial diversity in the moss phyllosphere, we used 16S rRNA gene amplicon sequencing to quantify changes in bacterial communities as a function of host species (Pleurozium schreberi and Ptilium crista-castrensis) and forest type (coniferous black spruce versus deciduous broadleaf trembling aspen) in eastern Canada. The overall composition of moss phyllosphere was defined by the interaction of both factors, though most of bacterial phyla were determined by a strong effect of forest type. Bacterial α-diversity was highest in spruce forests, while there was greater turnover (β-diversity) and higher γ-diversity in aspen forests. Unexpectedly, Cyanobacteria were much more relatively abundant in aspen than in spruce forests, with the cyanobacteria family Nostocaceae differing the most between forest types. Our results advance the understanding of moss-associated microbial communities among coniferous and broadleaf deciduous forests, which are important with the increasing changes in tree dominance in the boreal system. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Juanita C Rodríguez-Rodríguez
- Forest Research Institute (IRF) , Université du Québec en Abitibi-Témiscamingue (UQAT), Rouyn-Noranda, QC J9X 5E4, Canada. 2 Département des sciences biologiques, Université du Québec à Montréal (UQAM), Montréal, QC, H2L 2C4, Canada
| | - Yves Bergeron
- Forest Research Institute (IRF) , Université du Québec en Abitibi-Témiscamingue (UQAT), Rouyn-Noranda, QC J9X 5E4, Canada. 2 Département des sciences biologiques, Université du Québec à Montréal (UQAM), Montréal, QC, H2L 2C4, Canada
| | | | - Nicole J Fenton
- Forest Research Institute (IRF) , Université du Québec en Abitibi-Témiscamingue (UQAT), Rouyn-Noranda, QC J9X 5E4, Canada. 2 Département des sciences biologiques, Université du Québec à Montréal (UQAM), Montréal, QC, H2L 2C4, Canada
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