1
|
VanderRoest JP, Fowler JA, Rhoades CC, Roth HK, Broeckling CD, Fegel TS, McKenna AM, Bechtold EK, Boot CM, Wilkins MJ, Borch T. Fire Impacts on the Soil Metabolome and Organic Matter Biodegradability. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:4167-4180. [PMID: 38385432 DOI: 10.1021/acs.est.3c09797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Global wildfire activity has increased since the 1970s and is projected to intensify throughout the 21st century. Wildfires change the composition and biodegradability of soil organic matter (SOM) which contains nutrients that fuel microbial metabolism. Though persistent forms of SOM often increase postfire, the response of more biodegradable SOM remains unclear. Here we simulated severe wildfires through a controlled "pyrocosm" approach to identify biodegradable sources of SOM and characterize the soil metabolome immediately postfire. Using microbial amplicon (16S/ITS) sequencing and gas chromatography-mass spectrometry, heterotrophic microbes (Actinobacteria, Firmicutes, and Protobacteria) and specific metabolites (glycine, protocatechuate, citric cycle intermediates) were enriched in burned soils, indicating that burned soils contain a variety of substrates that support microbial metabolism. Molecular formulas assigned by 21 T Fourier transform ion cyclotron resonance mass spectrometry showed that SOM in burned soil was lower in molecular weight and featured 20 to 43% more nitrogen-containing molecular formulas than unburned soil. We also measured higher water extractable organic carbon concentrations and higher CO2 efflux in burned soils. The observed enrichment of biodegradable SOM and microbial heterotrophs demonstrates the resilience of these soils to severe burning, providing important implications for postfire soil microbial and plant recolonization and ecosystem recovery.
Collapse
Affiliation(s)
- Jacob P VanderRoest
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80521, United States
| | - Julie A Fowler
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado 80521, United States
| | - Charles C Rhoades
- Rocky Mountain Research Station, U.S. Forest Service, Fort Collins, Colorado 80526, United States
| | - Holly K Roth
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado 80521, United States
| | - Corey D Broeckling
- Bioanalysis and Omics Center, Analytical Resources Core, Colorado State University, Fort Collins, 80521, United States
| | - Timothy S Fegel
- Rocky Mountain Research Station, U.S. Forest Service, Fort Collins, Colorado 80526, United States
| | - Amy M McKenna
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado 80521, United States
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Dr., Tallahassee, Florida 32310, United States
| | - Emily K Bechtold
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado 80521, United States
| | - Claudia M Boot
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80521, United States
| | - Michael J Wilkins
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado 80521, United States
| | - Thomas Borch
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80521, United States
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado 80521, United States
| |
Collapse
|
2
|
Liu MD, Du Y, Koupaei SK, Kim NR, Fischer MS, Zhang W, Traxler MF. Surface-active antibiotic production as a multifunctional adaptation for postfire microorganisms. THE ISME JOURNAL 2024; 18:wrae022. [PMID: 38366029 PMCID: PMC11069360 DOI: 10.1093/ismejo/wrae022] [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: 12/22/2023] [Revised: 02/01/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Wildfires affect soils in multiple ways, leading to numerous challenges for colonizing microorganisms. Although it is thought that fire-adapted microorganisms lie at the forefront of postfire ecosystem recovery, the specific strategies that these organisms use to thrive in burned soils remain largely unknown. Through bioactivity screening of bacterial isolates from burned soils, we discovered that several Paraburkholderia spp. isolates produced a set of unusual rhamnolipid surfactants with a natural methyl ester modification. These rhamnolipid methyl esters (RLMEs) exhibited enhanced antimicrobial activity against other postfire microbial isolates, including pyrophilous Pyronema fungi and Amycolatopsis bacteria, compared to the typical rhamnolipids made by organisms such as Pseudomonas spp. RLMEs also showed enhanced surfactant properties and facilitated bacterial motility on agar surfaces. In vitro assays further demonstrated that RLMEs improved aqueous solubilization of polycyclic aromatic hydrocarbons, which are potential carbon sources found in char. Identification of the rhamnolipid biosynthesis genes in the postfire isolate, Paraburkholderia kirstenboschensis str. F3, led to the discovery of rhlM, whose gene product is responsible for the unique methylation of rhamnolipid substrates. RhlM is the first characterized bacterial representative of a large class of integral membrane methyltransferases that are widespread in bacteria. These results indicate multiple roles for RLMEs in the postfire lifestyle of Paraburkholderia isolates, including enhanced dispersal, solubilization of potential nutrients, and inhibition of competitors. Our findings shed new light on the chemical adaptations that bacteria employ to navigate, grow, and outcompete other soil community members in postfire environments.
Collapse
Affiliation(s)
- Mira D Liu
- Department of Chemistry, University of California, Berkeley, CA 94720, United States
| | - Yongle Du
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, United States
| | - Sara K Koupaei
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, United States
| | - Nicole R Kim
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, United States
| | - Monika S Fischer
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, United States
| | - Wenjun Zhang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, United States
| | - Matthew F Traxler
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, United States
| |
Collapse
|
3
|
Fischer MS, Patel NJ, de Lorimier PJ, Traxler MF. Prescribed fire selects for a pyrophilous soil sub-community in a northern California mixed conifer forest. Environ Microbiol 2023; 25:2498-2515. [PMID: 37553729 DOI: 10.1111/1462-2920.16475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 07/20/2023] [Indexed: 08/10/2023]
Abstract
Prescribed fire is a critical strategy for mitigating the effects of catastrophic wildfires. While the above-ground response to fire has been well-documented, fewer studies have addressed the effect of prescribed fire on soil microorganisms. To understand how soil microbial communities respond to prescribed fire, we sampled four plots at a high temporal resolution (two burned, two controls), for 17 months, in a mixed conifer forest in northern California, USA. Using amplicon sequencing, we found that prescribed fire significantly altered both fungal and bacterial community structure. We found that most differentially abundant fungal taxa had a positive fold-change, while differentially abundant bacterial taxa generally had a negative fold-change. We tested the null hypothesis that these communities assembled due to neutral processes (i.e., drift and/or dispersal), finding that >90% of taxa fit this neutral prediction. However, a dynamic sub-community composed of burn-associated indicator taxa that were positively differentially abundant was enriched for non-neutral amplicon sequence variants, suggesting assembly via deterministic processes. In synthesizing these results, we identified 15 pyrophilous taxa with a significant and positive response to prescribed burns. Together, these results lay the foundation for building a process-driven understanding of microbial community assembly in the context of the classical disturbance regime of fire.
Collapse
Affiliation(s)
- Monika S Fischer
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Neem J Patel
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Phillip J de Lorimier
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Matthew F Traxler
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| |
Collapse
|
4
|
Liu MD, Du Y, Koupaei SK, Kim NR, Zhang W, Traxler MF. Surface-active antibiotic production is a multifunctional adaptation for postfire microbes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.17.553728. [PMID: 37645719 PMCID: PMC10462131 DOI: 10.1101/2023.08.17.553728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Wildfires affect soils in multiple ways, leading to numerous challenges for colonizing microbes. While it is thought that fire-adapted microbes lie at the forefront of postfire ecosystem recovery, the specific strategies that these microbes use to thrive in burned soils remain largely unknown. Through bioactivity screening of bacterial isolates from burned soils, we discovered that several Paraburkholderia spp. isolates produced a set of unusual rhamnolipid surfactants with a natural methyl ester modification. These rhamnolipid methyl esters (RLMEs) exhibited enhanced antimicrobial activity against other postfire microbial isolates, including pyrophilous Pyronema fungi and Amycolatopsis bacteria, compared to the typical rhamnolipids made by organisms such as Pseudomonas spp . RLMEs also showed enhanced surfactant properties and facilitated bacterial motility on agar surfaces. In vitro assays further demonstrated that RLMEs improved aqueous solubilization of polycyclic aromatic hydrocarbons, which are potential carbon sources found in char. Identification of the rhamnolipid biosynthesis genes in the postfire isolate, Paraburkholderia caledonica str. F3, led to the discovery of rhlM , whose gene product is responsible for the unique methylation of rhamnolipid substrates. RhlM is the first characterized bacterial representative of a large class of integral membrane methyltransferases that are widespread in bacteria. These results indicate multiple roles for RLMEs in the postfire lifestyle of Paraburkholderia isolates, including enhanced dispersal, solubilization of potential nutrients, and inhibition of competitors. Our findings shed new light on the chemical adaptations that bacteria employ in order to navigate, grow, and outcompete other soil community members in postfire environments. Significance Statement Wildfires are increasing in frequency and intensity at a global scale. Microbes are the first colonizers of soil after fire events, but the adaptations that help these organisms survive in postfire environments are poorly understood. In this work, we show that a bacterium isolated from burned soil produces an unusual rhamnolipid biosurfactant that exhibits antimicrobial activity, enhances motility, and solubilizes potential nutrients derived from pyrolyzed organic matter. Collectively, our findings demonstrate that bacteria leverage specialized metabolites with multiple functions to meet the demands of life in postfire environments. Furthermore, this work reveals the potential of probing perturbed environments for the discovery of unique compounds and enzymes.
Collapse
|
5
|
Honeyman AS, Merl T, Spear JR, Koren K. Optode-based chemical imaging of laboratory burned soil reveals millimeter-scale heterogeneous biogeochemical responses. ENVIRONMENTAL RESEARCH 2023; 224:115469. [PMID: 36773636 DOI: 10.1016/j.envres.2023.115469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/16/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Soil spatial responses to fire are unclear. Using optical chemical sensing with planar 'optodes', pH and dissolved O2 concentration were tracked spatially with a resolution of 360 μm per pixel for 72 h after burning soil in the laboratory with a butane torch (∼1300 °C) and then sprinkling water to simulate a postfire moisture event. Imaging data from planar optodes correlated with microbial activity (quantified via RNA transcripts). Post-fire and post-wetting, soil pH increased throughout the entire ∼13 cm × 17 cm × 20 cm rectangular cuboid of sandy loam soil. Dissolved O2 concentrations were not impacted until the application of water postfire. pH and dissolved O2 both negatively correlated (p < 0.05) with relative transcript expression for galactose metabolism, the degradation of aromatic compounds, sulfur metabolism, and narH. Additionally, dissolved O2 negatively correlated (p < 0.05) with the relative activity of carbon fixation pathways in Bacteria and Archaea, amoA/amoB, narG, nirK, and nosZ. nifH was not detected in any samples. Only amoB and amoC correlated with depth in soil (p < 0.05). Results demonstrate that postfire soils are spatially complex on a mm scale and that using optode-based chemical imaging as a chemical navigator for RNA transcript sampling is effective.
Collapse
Affiliation(s)
- Alexander S Honeyman
- Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO, 80401, USA
| | - Theresa Merl
- Aarhus University Centre for Water Technology, Department of Biology, Section for Microbiology, Aarhus University, Ny Munkegade 114, 8000, Aarhus C, Denmark
| | - John R Spear
- Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO, 80401, USA; Quantitative Biosciences and Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO, 80401, USA.
| | - Klaus Koren
- Aarhus University Centre for Water Technology, Department of Biology, Section for Microbiology, Aarhus University, Ny Munkegade 114, 8000, Aarhus C, Denmark.
| |
Collapse
|
6
|
Imam A, Suman SK, Singh P, Vempatapu BP, Tripathi D, Ray A, Kanaujia PK. Proteomic response of Pseudomonas aeruginosa IIPIS-8 during rapid and efficient degradation of naphthalene. ENVIRONMENTAL RESEARCH 2023; 216:114511. [PMID: 36265600 DOI: 10.1016/j.envres.2022.114511] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/05/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the ecosystem and are of significant concern due to their toxicity and mutagenicity. Bioremediation of PAHs is a popular and benign approach that ameliorates the environment. This study investigated the biodegradation and proteome response of Pseudomonas aeruginosa IIPIS-8 for two-ringed PAH: naphthalene (NAP) to understand proteome alteration during its bioremediation. Rapid biodegradation was observed up to 98 ± 1.26% and 84 ± 1.03%, respectively, for initial concentrations of 100 mg L-1 and 500 mg L-1 of NAP. Degradation followed first-order kinetics with rate constants of 0.12 h-1 and 0.06 h-1 and half-life (t1/2) of 5.7 h and 11.3 h, respectively. Additionally, the occurrence of key ring cleavage and linear chain intermediates, 2,3,4,5,6, -pentamethyl acetophenone, 1-octanol 2-butyl, and hexadecanoic acid supported complete NAP degradation. Proteomics study of IIPIS-8 throws light on the impact of protein expression, in which 415 proteins were quantified in sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) analysis, of which 97 were found to be significantly up-regulated and 75 were significantly down-regulated by ≥ 2-fold change (p values ≤ 0.05), during the NAP degradation. The study also listed the up-regulation of several enzymes, including oxido-reductases, hydrolases, and catalases, potentially involved in NAP degradation. Overall, differential protein expression, through proteomics study, demonstrated IIPIS-8's capability to efficiently assimilate NAP in their metabolic pathways even in a high concentration of NAP.
Collapse
Affiliation(s)
- Arfin Imam
- Analytical Sciences Division, CSIR-Indian Institute of Petroleum, Haridwar Road, Dehradun, 248005, Uttarakhand, India; Material Resource Efficiency Division, CSIR-Indian Institute of Petroleum, Haridwar Road, Dehradun, 248005, Uttarakhand, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC Campus, Ghaziabad, 201002, India
| | - Sunil Kumar Suman
- Material Resource Efficiency Division, CSIR-Indian Institute of Petroleum, Haridwar Road, Dehradun, 248005, Uttarakhand, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC Campus, Ghaziabad, 201002, India.
| | - Praveen Singh
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, 110025, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC Campus, Ghaziabad, 201002, India
| | - Bhanu Prasad Vempatapu
- Analytical Sciences Division, CSIR-Indian Institute of Petroleum, Haridwar Road, Dehradun, 248005, Uttarakhand, India
| | - Deependra Tripathi
- Analytical Sciences Division, CSIR-Indian Institute of Petroleum, Haridwar Road, Dehradun, 248005, Uttarakhand, India
| | - Anjan Ray
- Analytical Sciences Division, CSIR-Indian Institute of Petroleum, Haridwar Road, Dehradun, 248005, Uttarakhand, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC Campus, Ghaziabad, 201002, India
| | - Pankaj K Kanaujia
- Analytical Sciences Division, CSIR-Indian Institute of Petroleum, Haridwar Road, Dehradun, 248005, Uttarakhand, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC Campus, Ghaziabad, 201002, India.
| |
Collapse
|
7
|
Pulido-Chavez MF, Randolph JWJ, Zalman C, Larios L, Homyak PM, Glassman SI. Rapid bacterial and fungal successional dynamics in first year after chaparral wildfire. Mol Ecol 2022; 32:1685-1707. [PMID: 36579900 DOI: 10.1111/mec.16835] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 11/30/2022] [Accepted: 12/08/2022] [Indexed: 12/30/2022]
Abstract
The rise in wildfire frequency and severity across the globe has increased interest in secondary succession. However, despite the role of soil microbial communities in controlling biogeochemical cycling and their role in the regeneration of post-fire vegetation, the lack of measurements immediately post-fire and at high temporal resolution has limited understanding of microbial secondary succession. To fill this knowledge gap, we sampled soils at 17, 25, 34, 67, 95, 131, 187, 286, and 376 days after a southern California wildfire in fire-adapted chaparral shrublands. We assessed bacterial and fungal biomass with qPCR of 16S and 18S and richness and composition with Illumina MiSeq sequencing of 16S and ITS2 amplicons. Fire severely reduced bacterial biomass by 47%, bacterial richness by 46%, fungal biomass by 86%, and fungal richness by 68%. The burned bacterial and fungal communities experienced rapid succession, with 5-6 compositional turnover periods. Analogous to plants, turnover was driven by "fire-loving" pyrophilous microbes, many of which have been previously found in forests worldwide and changed markedly in abundance over time. Fungal secondary succession was initiated by the Basidiomycete yeast Geminibasidium, which traded off against the filamentous Ascomycetes Pyronema, Aspergillus, and Penicillium. For bacteria, the Proteobacteria Massilia dominated all year, but the Firmicute Bacillus and Proteobacteria Noviherbaspirillum increased in abundance over time. Our high-resolution temporal sampling allowed us to capture post-fire microbial secondary successional dynamics and suggest that putative tradeoffs in thermotolerance, colonization, and competition among dominant pyrophilous microbes control microbial succession with possible implications for ecosystem function.
Collapse
Affiliation(s)
- M Fabiola Pulido-Chavez
- Department of Microbiology and Plant Pathology, University of California-Riverside, Riverside, California, USA
| | - James W J Randolph
- Department of Microbiology and Plant Pathology, University of California-Riverside, Riverside, California, USA
| | - Cassandra Zalman
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Loralee Larios
- Department of Botany and Plant Sciences, University of California-Riverside, Riverside, California, USA
| | - Peter M Homyak
- Department of Environmental Sciences, University of California-Riverside, Riverside, California, USA
| | - Sydney I Glassman
- Department of Microbiology and Plant Pathology, University of California-Riverside, Riverside, California, USA
| |
Collapse
|
8
|
Steindorff AS, Seong K, Carver A, Calhoun S, Fischer MS, Stillman K, Liu H, Drula E, Henrissat B, Simpson HJ, Schilling JS, Lipzen A, He G, Yan M, Andreopoulos B, Pangilinan J, LaButti K, Ng V, Traxler M, Bruns TD, Grigoriev IV. Diversity of genomic adaptations to the post-fire environment in Pezizales fungi points to crosstalk between charcoal tolerance and sexual development. THE NEW PHYTOLOGIST 2022; 236:1154-1167. [PMID: 35898177 DOI: 10.1111/nph.18407] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Wildfires drastically impact the soil environment, altering the soil organic matter, forming pyrolyzed compounds, and markedly reducing the diversity of microorganisms. Pyrophilous fungi, especially the species from the orders Pezizales and Agaricales, are fire-responsive fungal colonizers of post-fire soil that have historically been found fruiting on burned soil and thus may encode mechanisms of processing these compounds in their genomes. Pyrophilous fungi are diverse. In this work, we explored this diversity and sequenced six new genomes of pyrophilous Pezizales fungi isolated after the 2013 Rim Fire near Yosemite Park in California, USA: Pyronema domesticum, Pyronema omphalodes, Tricharina praecox, Geopyxis carbonaria, Morchella snyderi, and Peziza echinospora. A comparative genomics analysis revealed the enrichment of gene families involved in responses to stress and the degradation of pyrolyzed organic matter. In addition, we found that both protein sequence lengths and G + C content in the third base of codons (GC3) in pyrophilous fungi fall between those in mesophilic/nonpyrophilous and thermophilic fungi. A comparative transcriptome analysis of P. domesticum under two conditions - growing on charcoal, and during sexual development - identified modules of genes that are co-expressed in the charcoal and light-induced sexual development conditions. In addition, environmental sensors such as transcription factors STE12, LreA, LreB, VosA, and EsdC were upregulated in the charcoal condition. Taken together, these results highlight genomic adaptations of pyrophilous fungi and indicate a potential connection between charcoal tolerance and fruiting body formation in P. domesticum.
Collapse
Affiliation(s)
- Andrei S Steindorff
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Kyungyong Seong
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Plant and Microbial Biology Department, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Akiko Carver
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Plant and Microbial Biology Department, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Sara Calhoun
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Monika S Fischer
- Plant and Microbial Biology Department, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Kyra Stillman
- Plant and Microbial Biology Department, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Haowen Liu
- Plant and Microbial Biology Department, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Elodie Drula
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, 163 avenue de Luminy, 13288 Aix Marseille Université, Marseille, France
- INRAE, UMR 1163, Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
| | - Bernard Henrissat
- Department of Biological Sciences, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
- DTU Bioengineering, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Hunter J Simpson
- Department of Bioproducts and Biosystems Engineering, University of Minnesota, St Paul, MN, 55108, USA
| | - Jonathan S Schilling
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, 55108, USA
| | - Anna Lipzen
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Guifen He
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Mi Yan
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Bill Andreopoulos
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jasmyn Pangilinan
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Kurt LaButti
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Vivian Ng
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Matthew Traxler
- Plant and Microbial Biology Department, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Thomas D Bruns
- Plant and Microbial Biology Department, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Igor V Grigoriev
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Plant and Microbial Biology Department, University of California Berkeley, Berkeley, CA, 94720, USA
| |
Collapse
|
9
|
Roth HK, Nelson AR, McKenna AM, Fegel TS, Young RB, Rhoades CC, Wilkins MJ, Borch T. Impact of beaver ponds on biogeochemistry of organic carbon and nitrogen along a fire-impacted stream. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:1661-1677. [PMID: 36004537 DOI: 10.1039/d2em00184e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Wildfires, which are increasing in frequency and severity in the western U.S., impact water quality through increases in erosion, and transport of nutrients and metals. Meanwhile, beaver populations have been increasing since the early 1900s, and the ponds they create slow or impound hydrologic and elemental fluxes, increase soil saturation, and have a high potential to transform redox active elements (e.g., oxygen, nitrogen, sulfur, and metals). However, it remains unknown how the presence of beaver ponds in burned watersheds may impact retention and transformation of chemical constituents originating in burned uplands (e.g., pyrogenic dissolved organic matter; pyDOM) and the consequences for downstream water quality. Here, we investigate the impact of beaver ponds on the chemical properties and molecular composition of dissolved forms of C and N, and the microbial functional potential encoded within these environments. The chemistry and microbiology of surface water and sediment changed along a stream sequence starting upstream of fire and flowing through multiple beaver ponds and interconnecting stream reaches within a burned high-elevation forest watershed. The relative abundance of N-containing compounds increased in surface water of the burned beaver ponds, which corresponded to lower C/N and O/C, and higher aromaticity as characterized by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The resident microbial communities lack the capacity to process such aromatic pyDOM, though genomic analyses demonstrate their potential to metabolize various compounds in the anaerobic sediments of the beaver ponds. Collectively, this work highlights the role of beaver ponds as biological "hotspots" with unique biogeochemistry in fire-impacted systems.
Collapse
Affiliation(s)
- Holly K Roth
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA.
| | - Amelia R Nelson
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - Amy M McKenna
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
- National High Magnetic Field Laboratory, Ion Cyclotron Resonance Facility, Florida State University, FL, USA
| | - Timothy S Fegel
- Rocky Mountain Research Station, U.S. Forest Service, Fort Collins, CO, USA
| | - Robert B Young
- Chemical Analysis & Instrumentation Laboratory, New Mexico State University, Las Cruces, NM, USA
| | - Charles C Rhoades
- Rocky Mountain Research Station, U.S. Forest Service, Fort Collins, CO, USA
| | - Michael J Wilkins
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - Thomas Borch
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA.
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| |
Collapse
|
10
|
Nelson AR, Narrowe AB, Rhoades CC, Fegel TS, Daly RA, Roth HK, Chu RK, Amundson KK, Young RB, Steindorff AS, Mondo SJ, Grigoriev IV, Salamov A, Borch T, Wilkins MJ. Wildfire-dependent changes in soil microbiome diversity and function. Nat Microbiol 2022; 7:1419-1430. [PMID: 36008619 PMCID: PMC9418001 DOI: 10.1038/s41564-022-01203-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 07/18/2022] [Indexed: 12/13/2022]
Abstract
Forest soil microbiomes have crucial roles in carbon storage, biogeochemical cycling and rhizosphere processes. Wildfire season length, and the frequency and size of severe fires have increased owing to climate change. Fires affect ecosystem recovery and modify soil microbiomes and microbially mediated biogeochemical processes. To study wildfire-dependent changes in soil microbiomes, we characterized functional shifts in the soil microbiota (bacteria, fungi and viruses) across burn severity gradients (low, moderate and high severity) 1 yr post fire in coniferous forests in Colorado and Wyoming, USA. We found severity-dependent increases of Actinobacteria encoding genes for heat resistance, fast growth, and pyrogenic carbon utilization that might enhance post-fire survival. We report that increased burn severity led to the loss of ectomycorrhizal fungi and less tolerant microbial taxa. Viruses remained active in post-fire soils and probably influenced carbon cycling and biogeochemistry via turnover of biomass and ecosystem-relevant auxiliary metabolic genes. Our genome-resolved analyses link post-fire soil microbial taxonomy to functions and reveal the complexity of post-fire soil microbiome activity.
Collapse
Affiliation(s)
- Amelia R Nelson
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - Adrienne B Narrowe
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
- Eastern Regional Research Center, Agricultural Research Service, Wyndmoor, PA, USA
| | - Charles C Rhoades
- Rocky Mountain Research Station, U.S. Forest Service, Fort Collins, CO, USA
| | - Timothy S Fegel
- Rocky Mountain Research Station, U.S. Forest Service, Fort Collins, CO, USA
| | - Rebecca A Daly
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - Holly K Roth
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | - Rosalie K Chu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Kaela K Amundson
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - Robert B Young
- Chemical Analysis and Instrumentation Laboratory, New Mexico State University, Las Cruces, NM, USA
| | - Andrei S Steindorff
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Stephen J Mondo
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, USA
| | - Igor V Grigoriev
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, USA
| | - Asaf Salamov
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Thomas Borch
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
- Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USA
| | - Michael J Wilkins
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA.
| |
Collapse
|
11
|
How microorganisms in the soil respond to and are altered by forest wildfire. Nat Microbiol 2022; 7:1329-1330. [PMID: 36008620 DOI: 10.1038/s41564-022-01218-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
12
|
Ecological and genomic responses of soil microbiomes to high-severity wildfire: linking community assembly to functional potential. THE ISME JOURNAL 2022; 16:1853-1863. [PMID: 35430593 PMCID: PMC9213548 DOI: 10.1038/s41396-022-01232-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 03/06/2022] [Accepted: 03/28/2022] [Indexed: 12/14/2022]
Abstract
Increasing wildfire severity, which is common throughout the western United States, can have deleterious effects on plant regeneration and large impacts on carbon (C) and nitrogen (N) cycling rates. Soil microbes are pivotal in facilitating these elemental cycles, so understanding the impact of increasing fire severity on soil microbial communities is critical. Here, we assess the long-term impact of high-severity fires on the soil microbiome. We find that high-severity wildfires result in a multi-decadal (>25 y) recovery of the soil microbiome mediated by concomitant differences in aboveground vegetation, soil chemistry, and microbial assembly processes. Our results depict a distinct taxonomic and functional successional pattern of increasing selection in post-fire soil microbial communities. Changes in microbiome composition corresponded with changes in microbial functional potential, specifically altered C metabolism and enhanced N cycling potential, which related to rates of potential decomposition and inorganic N availability, respectively. Based on metagenome-assembled genomes, we show that bacterial genomes enriched in our earliest site (4 y since fire) harbor distinct traits such as a robust stress response and a high potential to degrade pyrogenic, polyaromatic C that allow them to thrive in post-fire environments. Taken together, these results provide a biological basis for previously reported process rate measurements and explain the temporal dynamics of post-fire biogeochemistry, which ultimately constrains ecosystem recovery.
Collapse
|
13
|
Senn S, Bhattacharyya S, Presley G, Taylor AE, Nash B, Enke RA, Barnard-Kubow KB, Ford J, Jasinski B, Badalova Y. The Functional Biogeography of eDNA Metacommunities in the Post-Fire Landscape of the Angeles National Forest. Microorganisms 2022; 10:microorganisms10061218. [PMID: 35744735 PMCID: PMC9229275 DOI: 10.3390/microorganisms10061218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/29/2022] [Accepted: 05/30/2022] [Indexed: 02/01/2023] Open
Abstract
Wildfires have continued to increase in frequency and severity in Southern California due in part to climate change. To gain a further understanding of microbial soil communities’ response to fire and functions that may enhance post-wildfire resilience, soil fungal and bacterial microbiomes were studied from different wildfire areas in the Gold Creek Preserve within the Angeles National Forest using 16S, FITS, 18S, 12S, PITS, and COI amplicon sequencing. Sequencing datasets from December 2020 and June 2021 samplings were analyzed using QIIME2, ranacapa, stats, vcd, EZBioCloud, and mixomics. Significant differences were found among bacterial and fungal taxa associated with different fire areas in the Gold Creek Preserve. There was evidence of seasonal shifts in the alpha diversity of the bacterial communities. In the sparse partial least squares analysis, there were strong associations (r > 0.8) between longitude, elevation, and a defined cluster of Amplicon Sequence Variants (ASVs). The Chi-square test revealed differences in fungi−bacteria (F:B) proportions between different trails (p = 2 × 10−16). sPLS results focused on a cluster of Green Trail samples with high elevation and longitude. Analysis revealed the cluster included the post-fire pioneer fungi Pyronema and Tremella. Chlorellales algae and possibly pathogenic Fusarium sequences were elevated. Bacterivorous Corallococcus, which secretes antimicrobials, and bacterivorous flagellate Spumella were associated with the cluster. There was functional redundancy in clusters that were differently composed but shared similar ecological functions. These results implied a set of traits for post-fire resiliency. These included photo-autotrophy, mineralization of pyrolyzed organic matter and aromatic/oily compounds, potential pathogenicity and parasitism, antimicrobials, and N-metabolism.
Collapse
Affiliation(s)
- Savanah Senn
- Department of Agriculture Sciences, Los Angeles Pierce College, 6201 Winnetka Avenue, PMB 553, Woodland Hills, CA 91304, USA; (J.F.); (B.J.); (Y.B.)
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, OR 97331, USA; (S.B.); (G.P.); (A.E.T.)
- Correspondence:
| | - Sharmodeep Bhattacharyya
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, OR 97331, USA; (S.B.); (G.P.); (A.E.T.)
- Department of Statistics, Oregon State University, Corvallis, OR 97331, USA
| | - Gerald Presley
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, OR 97331, USA; (S.B.); (G.P.); (A.E.T.)
- Department of Wood Science & Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Anne E. Taylor
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, OR 97331, USA; (S.B.); (G.P.); (A.E.T.)
- Department of Crop and Soil Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Bruce Nash
- DNA Learning Center, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA;
| | - Ray A. Enke
- Department of Biology, Center for Genome & Metagenome Studies, James Madison University, Harrisonburg, VA 22807, USA; (R.A.E.); (K.B.B.-K.)
| | - Karen B. Barnard-Kubow
- Department of Biology, Center for Genome & Metagenome Studies, James Madison University, Harrisonburg, VA 22807, USA; (R.A.E.); (K.B.B.-K.)
| | - Jillian Ford
- Department of Agriculture Sciences, Los Angeles Pierce College, 6201 Winnetka Avenue, PMB 553, Woodland Hills, CA 91304, USA; (J.F.); (B.J.); (Y.B.)
| | - Brandon Jasinski
- Department of Agriculture Sciences, Los Angeles Pierce College, 6201 Winnetka Avenue, PMB 553, Woodland Hills, CA 91304, USA; (J.F.); (B.J.); (Y.B.)
| | - Yekaterina Badalova
- Department of Agriculture Sciences, Los Angeles Pierce College, 6201 Winnetka Avenue, PMB 553, Woodland Hills, CA 91304, USA; (J.F.); (B.J.); (Y.B.)
| |
Collapse
|