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Li C, Yang S, Zhang M, Yang Y, Li Z, Peng L. SntB Affects Growth to Regulate Infecting Potential in Penicillium italicum. J Fungi (Basel) 2024; 10:368. [PMID: 38921355 PMCID: PMC11204802 DOI: 10.3390/jof10060368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/15/2024] [Accepted: 05/18/2024] [Indexed: 06/27/2024] Open
Abstract
Penicillium italicum, a major postharvest pathogen, causes blue mold rot in citrus fruits through the deployment of various virulence factors. Recent studies highlight the role of the epigenetic reader, SntB, in modulating the pathogenicity of phytopathogenic fungi. Our research revealed that the deletion of the SntB gene in P. italicum led to significant phenotypic alterations, including delayed mycelial growth, reduced spore production, and decreased utilization of sucrose. Additionally, the mutant strain exhibited increased sensitivity to pH fluctuations and elevated iron and calcium ion stress, culminating in reduced virulence on Gannan Novel oranges. Ultrastructural analyses disclosed notable disruptions in cell membrane integrity, disorganization within the cellular matrix, and signs of autophagy. Transcriptomic data further indicated a pronounced upregulation of hydrolytic enzymes, oxidoreductases, and transport proteins, suggesting a heightened energy demand. The observed phenomena were consistent with a carbon starvation response potentially triggering apoptotic pathways, including iron-dependent cell death. These findings collectively underscored the pivotal role of SntB in maintaining the pathogenic traits of P. italicum, proposing that targeting PiSntB could offer a new avenue for controlling citrus fungal infections and subsequent fruit decay.
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Affiliation(s)
| | | | | | | | | | - Litao Peng
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (C.L.); (S.Y.)
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Nagappan J, Ooi SE, Chan KL, Kadri F, Nurazah Z, Halim MAA, Angel LPL, Sundram S, Chin CF, May ST, Low ETL. Transcriptional effects of carbon and nitrogen starvation on Ganoderma boninense, an oil palm phytopathogen. Mol Biol Rep 2024; 51:212. [PMID: 38273212 DOI: 10.1007/s11033-023-09054-4] [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: 05/22/2023] [Accepted: 10/24/2023] [Indexed: 01/27/2024]
Abstract
BACKGROUND Ganoderma boninense is a phytopathogen of oil palm, causing basal and upper stem rot diseases. METHODS The genome sequence was used as a reference to study gene expression during growth in a starved carbon (C) and nitrogen (N) environment with minimal sugar and sawdust as initial energy sources. This study was conducted to mimic possible limitations of the C-N nutrient sources during the growth of G. boninense in oil palm plantations. RESULTS Genome sequencing of an isolate collected from a palm tree in West Malaysia generated an assembly of 67.12 Mb encoding 19,851 predicted genes. Transcriptomic analysis from a time course experiment during growth in this starvation media identified differentially expressed genes (DEGs) that were found to be associated with 29 metabolic pathways. During the active growth phase, 26 DEGs were related to four pathways, including secondary metabolite biosynthesis, carbohydrate metabolism, glycan metabolism and mycotoxin biosynthesis. G. boninense genes involved in the carbohydrate metabolism pathway that contribute to the degradation of plant cell walls were up-regulated. Interestingly, several genes associated with the mycotoxin biosynthesis pathway were identified as playing a possible role in pathogen-host interaction. In addition, metabolomics analysis revealed six metabolites, maltose, xylobiose, glucooligosaccharide, glycylproline, dimethylfumaric acid and arabitol that were up-regulated on Day2 of the time course experiment. CONCLUSIONS This study provides information on genes expressed by G. boninense in metabolic pathways that may play a role in the initial infection of the host.
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Affiliation(s)
- Jayanthi Nagappan
- Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000, Kajang, Selangor, Malaysia
- School of Biosciences, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor, Malaysia
| | - Siew-Eng Ooi
- Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000, Kajang, Selangor, Malaysia
| | - Kuang-Lim Chan
- Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000, Kajang, Selangor, Malaysia
| | - Faizun Kadri
- Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000, Kajang, Selangor, Malaysia
| | - Zain Nurazah
- Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000, Kajang, Selangor, Malaysia
| | - Mohd Amin Ab Halim
- Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000, Kajang, Selangor, Malaysia
| | - Lee Pei Lee Angel
- Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000, Kajang, Selangor, Malaysia
| | - Shamala Sundram
- Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000, Kajang, Selangor, Malaysia
| | - Chiew-Foan Chin
- School of Biosciences, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor, Malaysia
| | - Sean T May
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Nr Loughborough, LE12 5RD, UK
| | - Eng Ti Leslie Low
- Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000, Kajang, Selangor, Malaysia.
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Peng L, Zhang Y, Druzhinina IS, Kubicek CP, Wang Y, Zhu Z, Zhang Y, Wang K, Liu Z, Zhang X, Martin F, Yuan Z. A facultative ectomycorrhizal association is triggered by organic nitrogen. Curr Biol 2022; 32:5235-5249.e7. [PMID: 36402137 DOI: 10.1016/j.cub.2022.10.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 09/19/2022] [Accepted: 10/25/2022] [Indexed: 11/19/2022]
Abstract
Increasing nitrogen (N) deposition often tends to negatively impact the functions of belowground ectomycorrhizal networks, although the exact molecular mechanisms underlying this trait are still unclear. Here, we assess how the root-associated fungus Clitopilus hobsonii establishes an ectomycorrhiza-like association with its host tree Populus tomentosa and how this interaction is favored by organic N over mineral N. The establishment of a functional symbiosis in the presence of organic N promotes plant growth and the transfer of 15N from the fungus to above ground plant tissues. Genomic traits and in planta transcriptional signatures suggest that C. hobsonii may have a dual lifestyle with saprotrophic and mutualistic traits. For example, several genes involved in the digestion of cellulose and hemicellulose are highly expressed during the interaction, whereas the expression of multiple copies of pectin-digesting genes is tightly controlled. Conversely, the nutritional mutualism is dampened in the presence of ammonium (NH4+) or nitrate (NO3-). Increasing levels of NH4+ led to a higher expression of pectin-digesting genes and a continuous increase in hydrogen peroxide production in roots, whereas the presence of NO3- resulted in toxin production. In summary, our results suggest that C. hobsonii is a facultative ectomycorrhizal fungus. Access to various forms of N acts as an on/off switch for mutualism caused by large-scale fungal physiological remodeling. Furthermore, the abundance of pectin-degrading enzymes with distinct expression patterns during functional divergence after exposure to NH4+ or organic N is likely to be central to the transition from parasitism to mutualism.
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Affiliation(s)
- Long Peng
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Yan Zhang
- Liaoning Provincial Institute of Poplar, Gaizhou 115213, China
| | | | - Christian P Kubicek
- Institute of Chemical, Environmental & Bioscience Engineering (ICEBE), TU Wien, Vienna A1060, Austria
| | - Yuchen Wang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Zhiyong Zhu
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Yuwei Zhang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Kexuan Wang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Zhuo Liu
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Xiaoguo Zhang
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Francis Martin
- Université de Lorraine, INRAE, UMR 1136 "Interactions Arbres/Microorganismes," Centre INRAE Grand Est - Nancy, Champenoux 54280, France.
| | - Zhilin Yuan
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China.
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Fischer MS, Stark FG, Berry TD, Zeba N, Whitman T, Traxler MF. Pyrolyzed Substrates Induce Aromatic Compound Metabolism in the Post-fire Fungus, Pyronema domesticum. Front Microbiol 2021; 12:729289. [PMID: 34777277 PMCID: PMC8579045 DOI: 10.3389/fmicb.2021.729289] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/22/2021] [Indexed: 11/25/2022] Open
Abstract
Wildfires represent a fundamental and profound disturbance in many ecosystems, and their frequency and severity are increasing in many regions of the world. Fire affects soil by removing carbon in the form of CO2 and transforming remaining surface carbon into pyrolyzed organic matter (PyOM). Fires also generate substantial necromass at depths where the heat kills soil organisms but does not catalyze the formation of PyOM. Pyronema species strongly dominate soil fungal communities within weeks to months after fire. However, the carbon pool (i.e., necromass or PyOM) that fuels their rise in abundance is unknown. We used a Pyronema domesticum isolate from the catastrophic 2013 Rim Fire (CA, United States) to ask whether P. domesticum is capable of metabolizing PyOM. Pyronema domesticum grew readily on agar media where the sole carbon source was PyOM (specifically, pine wood PyOM produced at 750°C). Using RNAseq, we investigated the response of P. domesticum to PyOM and observed a comprehensive induction of genes involved in the metabolism and mineralization of aromatic compounds, typical of those found in PyOM. Lastly, we used 13C-labeled 750°C PyOM to demonstrate that P. domesticum is capable of mineralizing PyOM to CO2. Collectively, our results indicate a robust potential for P. domesticum to liberate carbon from PyOM in post-fire ecosystems and return it to the bioavailable carbon pool.
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Affiliation(s)
- Monika S. Fischer
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Frances Grace Stark
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Timothy D. Berry
- Department of Soil Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Nayela Zeba
- Department of Soil Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Thea Whitman
- Department of Soil Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Matthew F. Traxler
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
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5
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Novel hypoglycemic compounds from wild mushroom Paxillus involutus. Bioorg Chem 2021; 112:104984. [PMID: 34004479 DOI: 10.1016/j.bioorg.2021.104984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 12/13/2022]
Abstract
Wild mushrooms are an important source of secondary metabolites possessing a broad range of biological activities. In this study, eight new compounds, named furanopaxin A-F (1-6), deoxybisinvolutone (7), and coumarinvol (8) along with two known compounds were isolated from fruiting bodies of the wild mushroom Paxillus involutus (Batsch) Fr. Their structures were established based on HR-ESI-MS and 1D and 2D NMR spectroscopic data. The results of hypoglycemic assays indicated that compounds 5-8 possessed significant α-glucosidase inhibitory activities, with IC50 values ranging from 14.65 ± 1.68 to 47.55 ± 1.47 μM, and each compound could enhance glucose consumption in insulin-resistance HepG2 cells. Further analysis by molecular docking implied that compounds 5-8 could interact with the amino acid residues of α-glucosidase, supporting the hypoglycemic activity of the compounds.
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Lv JH, Yao L, Zhang JX, Wang LA, Zhang J, Wang YP, Xiao SY, Li CT, Li Y. Novel 2,5-Diarylcyclopentenone Derivatives from the Wild Edible Mushroom Paxillus involutus and Their Antioxidant Activities. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:5040-5048. [PMID: 33886290 DOI: 10.1021/acs.jafc.1c01160] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Wild edible mushrooms are important as a source of nutraceuticals and for the discovery of bioactive metabolites as pharmaceuticals. In this work, 10 rare 2,5-diarylcyclopentenone derivatives were isolated from the wild edible mushroom Paxillus involutus (Batsch) Fr., including eight novel compounds termed involutenone A-H (1-8) and two previously identified compounds (9-10). Their structures were established using high-resolution electrospray ionization mass spectroscopy and 1D and 2D nuclear magnetic resonance data. The absolute configurations of compounds 1-3 and 6-8 were assigned based on the comparison of the experimental and calculated electronic circular dichroism data. The antioxidant activities of 1-8 were tested through DPPH free radical scavenging, hydroxyl radical scavenging, and superoxide anion radical scavenging assays. Compounds 3, 5, 6, and 7 demonstrated significant antioxidant activity compared to the positive control (tert-butylhydroquinone). These compounds could be effective natural antioxidants with considerable pharmaceutical value.
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Affiliation(s)
- Jian-Hua Lv
- Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun 130118, People's Republic of China
| | - Lan Yao
- Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun 130118, People's Republic of China
| | - Jin-Xiu Zhang
- The Life Science College, Hebei Normal University, Shijiazhuang 050024, People's Republic of China
| | - Li-An Wang
- The Life Science College, Hebei Normal University, Shijiazhuang 050024, People's Republic of China
| | - Jun Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Ying-Ping Wang
- National and Local Joint Engineering Research Center for Breeding and Development of New Ginseng Varieties, Jilin Agricultural University, Changchun 130118, People's Republic of China
| | - Sheng-Yuan Xiao
- National and Local Joint Engineering Research Center for Breeding and Development of New Ginseng Varieties, Jilin Agricultural University, Changchun 130118, People's Republic of China
| | - Chang-Tian Li
- Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun 130118, People's Republic of China
| | - Yu Li
- Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun 130118, People's Republic of China
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7
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Lv JH, Yao L, Duan C, Li Z, Zhang J, Li CT, Li Y. New bioactive α-pyrone from wild mushroom Paxillus involutus. Nat Prod Res 2021; 36:2707-2712. [PMID: 33949256 DOI: 10.1080/14786419.2021.1920020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Chemical investigation of Paxillus involutus (Batsch) Fr. led to the isolation of a pair of new enantiomers (E)-5-(4-methoxy-2-oxo-2H-pyran-6-yl)pent-4-en-1-yl 2-hydroxypropanoate (1a/1b) along with 14 known compounds (2-15) for the first time from this mushroom. The structures of new compounds were elucidated based on extensive spectroscopic data analysis of MS, 1D and 2D NMR, and their absolute configurations were confirmed by comparison of the experimental and calculated ECD data. Compounds 1a and 1b exhibited radical scavenging activities with IC50 values ranging from 10.39 ± 2.26 to 20.43 ± 3.74 μg/mL. Compounds 1a and 1b also showed moderate anti-tyrosinase activity with IC50 value of 25.66 ± 2.84 and 26.82 ± 3.19 μg/mL.
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Affiliation(s)
- Jian-Hua Lv
- Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun, PR China
| | - Lan Yao
- Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun, PR China
| | - Chao Duan
- Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun, PR China
| | - Zhuang Li
- College of Life Science, Hebei University, Baoding, PR China
| | - Jun Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, PR China
| | - Chang-Tian Li
- Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun, PR China
| | - Yu Li
- Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun, PR China
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8
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Wang T, Persson P, Tunlid A. A widespread mechanism in ectomycorrhizal fungi to access nitrogen from mineral-associated proteins. Environ Microbiol 2021; 23:5837-5849. [PMID: 33891367 DOI: 10.1111/1462-2920.15539] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 11/27/2022]
Abstract
A large fraction of nitrogen (N) in forest soils is present in mineral-associated proteinaceous compounds. The strong association between proteins and minerals limits microbial accessibility to this source, which is a relatively stable reservoir of soil N. We have shown that the ectomycorrhizal (ECM) fungus Paxillus involutus can acquire N from iron oxide-associated proteins. Using tightly controlled isotopic, spectroscopic and chromatographic experiments, we demonstrated that the capacity to access N from iron oxide-associated bovine serum albumin (BSA) is shared with the ECM fungi Hebeloma cylindrosporum and Piloderma olivaceum. Despite differences in evolutionary history, growth rates, exploration types and the decomposition mechanisms of organic matter, their N acquisition mechanisms were similar to those described for P. involutus. The fungi released N from mineral-associated BSA by direct action of extracellular aspartic proteases on the mineral-associated BSA, without initial desorption of the protein. Hydrolysis was suppressed by the adsorption of proteases to minerals, but this adverse effect was counteracted by the secretion of compounds that conditioned the mineral surface. These data suggest that the enzymatic exudate-driven mechanism to access N from mineral-associated proteins is found in ECM fungi of multiple lineages and exploration types.
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Affiliation(s)
- Tao Wang
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, Lund, SE-223 62, Sweden.,CAS Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Per Persson
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, Lund, SE-223 62, Sweden.,Centre for Environmental and Climate Research (CEC), Lund University, Ecology Building, Lund, SE-223 62, Sweden
| | - Anders Tunlid
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, Lund, SE-223 62, Sweden
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9
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Smith JM, Whiteside MD, Jones MD. Rapid nitrogen loss from ectomycorrhizal pine germinants signaled by their fungal symbiont. MYCORRHIZA 2020; 30:407-417. [PMID: 32363468 PMCID: PMC7314718 DOI: 10.1007/s00572-020-00959-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 04/17/2020] [Indexed: 06/11/2023]
Abstract
Ectomycorrhizal fungi supply their plant partners with nitrogen but can also retain substantial amounts. The concentration of nitrogen in the soil and the amount of carbon supplied from the host seem to influence the proportion of N retained by the fungus. In an experiment designed to determine whether differential supply of nitrogen to two plants influenced nitrogen transfer from fungus to plant within a mycorrhizal network, we observed rapid, substantial loss of nitrogen from pine seedlings. The loss occurred when the mycorrhizal fungus experienced a sudden increase in nitrogen supply. We grew Pinus contorta seedlings in association with Suillus tomentosus in low-nitrogen microcosms where some nitrogen was accessible only by hyphae. After 70 days, foliage of some seedlings was treated with nitrogen. Three days later, hyphal nutrient media were replaced with water or a solution containing nitrogen. Foliar treatment did not affect nitrogen transfer by the fungus to shoots, but by day 75, seedling nitrogen contents had dropped by 60% in microcosms where nitrogen had been added to the hyphal compartments. Those seedlings retained only 55% of the nitrogen originally present in the seed. Loss of nitrogen did not occur if water was added or the hyphae were severed. Because of the severing effect, we concluded that S. tomentosus triggered the loss of seedling nitrogen. Nitrogen may have been lost through increased root exudation or transfer to the fungus. Access to nitrogen from nutrient-rich germinants would benefit rhizosphere microorganisms, including ectomycorrhizal fungi colonizing pine from spores after wildfire.
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Affiliation(s)
- Joshua M Smith
- Biology Department and Okanagan Institute of Biodiversity Resilience and Ecosystem Services, University of British Columbia, Okanagan campus, Kelowna, British Columbia, V1V 1V7, Canada
- Xeriscape Endemic Nursery & Ecological Solutions, West Kelowna, British Columbia, V1Z 1Z9, Canada
| | - Matthew D Whiteside
- Biology Department and Okanagan Institute of Biodiversity Resilience and Ecosystem Services, University of British Columbia, Okanagan campus, Kelowna, British Columbia, V1V 1V7, Canada
| | - Melanie D Jones
- Biology Department and Okanagan Institute of Biodiversity Resilience and Ecosystem Services, University of British Columbia, Okanagan campus, Kelowna, British Columbia, V1V 1V7, Canada.
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Unveiling of Concealed Processes for the Degradation of Pharmaceutical Compounds by Neopestalotiopsis sp. Microorganisms 2019; 7:microorganisms7080264. [PMID: 31426384 PMCID: PMC6722755 DOI: 10.3390/microorganisms7080264] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/09/2019] [Accepted: 08/15/2019] [Indexed: 01/15/2023] Open
Abstract
The presence of pharmaceutical products has raised emerging biorisks in aquatic environments. Fungi have been considered in sustainable approaches for the degradation of pharmaceutical compounds from aquatic environments. Soft rot fungi of the Ascomycota phylum are the most widely distributed among fungi, but their ability to biodegrade pharmaceuticals has not been studied as much as that of white rot fungi of the Basidiomycota phylum. Herein, we evaluated the capacity of the soft rot fungus Neopestalotiopsis sp. B2B to degrade pharmaceuticals under treatment of woody and nonwoody lignocellulosic biomasses. Nonwoody rice straw induced laccase activity fivefold compared with that in YSM medium containing polysaccharide. But B2B preferentially degraded polysaccharide over lignin regions in woody sources, leading to high concentrations of sugar. Hence, intermediate products from saccharification may inhibit laccase activity and thereby halt the biodegradation of pharmaceutical compounds. These results provide fundamental insights into the unique characteristics of pharmaceutical degradation by soft rot fungus Neopestalotiopsis sp. in the presence of preferred substrates during delignification.
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Wood Modification by Furfuryl Alcohol Resulted in a Delayed Decomposition Response in Rhodonia ( Postia) placenta. Appl Environ Microbiol 2019; 85:AEM.00338-19. [PMID: 31076422 PMCID: PMC6606883 DOI: 10.1128/aem.00338-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/03/2019] [Indexed: 11/20/2022] Open
Abstract
Fungi are important decomposers of woody biomass in natural habitats. Investigation of the mechanisms employed by decay fungi in their attempt to degrade wood is important for both the basic scientific understanding of ecology and carbon cycling in nature and for applied uses of woody materials. For wooden building materials, long service life and carbon storage are essential, but decay fungi are responsible for massive losses of wood in service. Thus, the optimization of durable wood products for the future is of major importance. In this study, we have investigated the fungal genetic response to furfurylated wood, a commercial environmentally benign wood modification approach that improves the service life of wood in outdoor applications. Our results show that there is a delayed wood decay by the fungus as a response to furfurylated wood, and new knowledge about the mechanisms behind the delay is provided. The aim of this study was to investigate differential expression profiles of the brown rot fungus Rhodonia placenta (previously Postia placenta) harvested at several time points when grown on radiata pine (Pinus radiata) and radiata pine with three different levels of modification by furfuryl alcohol, an environmentally benign commercial wood protection system. The entire gene expression pattern of a decay fungus was followed in untreated and modified wood from initial to advanced stages of decay. The results support the current model of a two-step decay mechanism, with the expression of genes related to initial oxidative depolymerization, followed by an accumulation of transcripts of genes related to the hydrolysis of cell wall polysaccharides. When the wood decay process is finished, the fungus goes into starvation mode after five weeks when grown on unmodified radiata pine wood. The pattern of repression of oxidative processes and oxalic acid synthesis found in radiata pine at later stages of decay is not mirrored for the high-furfurylation treatment. The high treatment level provided a more unpredictable expression pattern throughout the incubation period. Furfurylation does not seem to directly influence the expression of core plant cell wall-hydrolyzing enzymes, as a delayed and prolonged, but similar, pattern was observed in the radiata pine and the modified experiments. This indicates that the fungus starts a common decay process in the modified wood but proceeds at a slower pace as access to the plant cell wall polysaccharides is restricted. This is further supported by the downregulation of hydrolytic enzymes for the high treatment level at the last harvest point (mass loss, 14%). Moreover, the mass loss does not increase during the last weeks. Collectively, this indicates a potential threshold for lower mass loss for the high-furfurylation treatment. IMPORTANCE Fungi are important decomposers of woody biomass in natural habitats. Investigation of the mechanisms employed by decay fungi in their attempt to degrade wood is important for both the basic scientific understanding of ecology and carbon cycling in nature and for applied uses of woody materials. For wooden building materials, long service life and carbon storage are essential, but decay fungi are responsible for massive losses of wood in service. Thus, the optimization of durable wood products for the future is of major importance. In this study, we have investigated the fungal genetic response to furfurylated wood, a commercial environmentally benign wood modification approach that improves the service life of wood in outdoor applications. Our results show that there is a delayed wood decay by the fungus as a response to furfurylated wood, and new knowledge about the mechanisms behind the delay is provided.
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Wang T, Tian Z, Tunlid A, Persson P. Influence of Ammonium on Formation of Mineral-Associated Organic Carbon by an Ectomycorrhizal Fungus. Appl Environ Microbiol 2019; 85:e03007-18. [PMID: 30877120 PMCID: PMC6498167 DOI: 10.1128/aem.03007-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/08/2019] [Indexed: 11/20/2022] Open
Abstract
The interactions between dissolved organic matter (DOM) and mineral particles are critical for the stabilization of soil organic matter (SOM) in terrestrial ecosystems. The processing of DOM by ectomycorrhizal fungi contributes to the formation of mineral-stabilized SOM by two contrasting pathways: the extracellular transformation of DOM (ex vivo pathway) and the secretion of mineral-surface-reactive metabolites (in vivo pathway). In this study, we examined how changes in nitrogen (N) availability affected the formation of mineral-associated carbon (C) from these two pathways. DOM was extracted from forest soils. The processing of this DOM by the ectomycorrhizal fungus Paxillus involutus was examined in laboratory-scale studies with different levels of ammonium. At low levels of ammonium (i.e., under N-limited conditions), the DOM components were slightly oxidized, and fungal C metabolites with iron-reducing activity were secreted. Ammonium amendments decreased the amount of C metabolites, and no additional oxidation of the organic matter was detected. In contrast, the hydrolytic activity and the secretion of N-containing compounds increased, particularly when high levels of ammonium were added. Under these conditions, C, but not N, limited fungal growth. Although the overall production of mineral-associated organic C was not affected by ammonium concentrations, the observed shifts in the activities of the ex vivo and in vivo pathways affected the composition of organic matter adsorbed onto the mineral particles. Such changes will affect the properties of organic matter-mineral associations and, thus, ultimately, the stabilization of SOM.IMPORTANCE Nitrogen (N) availability plays a critical role in the cycling and storage of soil organic matter (SOM). However, large uncertainties remain in predicting the net effect of N addition on soil organic carbon (C) storage due to the complex interactions between organic matter, microbial activity, and mineral particles that determine the formation of stable SOM. Here, we attempted to disentangle the effects of ammonium on these interactions in controlled microcosm experiments including the ectomycorrhizal fungus P.involutus and dissolved organic matter extracted from forest soils. Increased ammonium levels affected the fungal processing of the organic material as well as the secretion of extracellular metabolites. Although ammonium additions did not increase the net production of mineral-adsorbed C, changes in the decomposition and secretion pathways altered the composition of the adsorbed organic matter. These changes may influence the properties of the organic matter-mineral associations and, thus, the stabilization of SOM.
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Affiliation(s)
- Tao Wang
- Department of Biology, Microbial Ecology Group, Lund University, Lund, Sweden
| | - Zhaomo Tian
- Department of Biology, Microbial Ecology Group, Lund University, Lund, Sweden
- Centre for Environmental and Climate Research, Lund University, Lund, Sweden
| | - Anders Tunlid
- Department of Biology, Microbial Ecology Group, Lund University, Lund, Sweden
| | - Per Persson
- Department of Biology, Microbial Ecology Group, Lund University, Lund, Sweden
- Centre for Environmental and Climate Research, Lund University, Lund, Sweden
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The soil organic matter decomposition mechanisms in ectomycorrhizal fungi are tuned for liberating soil organic nitrogen. ISME JOURNAL 2018; 13:977-988. [PMID: 30538275 PMCID: PMC6461840 DOI: 10.1038/s41396-018-0331-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/27/2018] [Accepted: 11/28/2018] [Indexed: 02/08/2023]
Abstract
Many trees form ectomycorrhizal symbiosis with fungi. During symbiosis, the tree roots supply sugar to the fungi in exchange for nitrogen, and this process is critical for the nitrogen and carbon cycles in forest ecosystems. However, the extents to which ectomycorrhizal fungi can liberate nitrogen and modify the soil organic matter and the mechanisms by which they do so remain unclear since they have lost many enzymes for litter decomposition that were present in their free-living, saprotrophic ancestors. Using time-series spectroscopy and transcriptomics, we examined the ability of two ectomycorrhizal fungi from two independently evolved ectomycorrhizal lineages to mobilize soil organic nitrogen. Both species oxidized the organic matter and accessed the organic nitrogen. The expression of those events was controlled by the availability of glucose and inorganic nitrogen. Despite those similarities, the decomposition mechanisms, including the type of genes involved as well as the patterns of their expression, differed markedly between the two species. Our results suggest that in agreement with their diverse evolutionary origins, ectomycorrhizal fungi use different decomposition mechanisms to access organic nitrogen entrapped in soil organic matter. The timing and magnitude of the expression of the decomposition activity can be controlled by the below-ground nitrogen quality and the above-ground carbon supply.
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14
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Akroume E, Maillard F, Bach C, Hossann C, Brechet C, Angeli N, Zeller B, Saint-André L, Buée M. First evidences that the ectomycorrhizal fungusPaxillus involutusmobilizes nitrogen and carbon from saprotrophic fungus necromass. Environ Microbiol 2018; 21:197-208. [DOI: 10.1111/1462-2920.14440] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 10/05/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Emila Akroume
- INRA, UMR1136 Interactions Arbres-Microorganismes; F-54280, Champenoux France
- Université de Lorraine, UMR1136 Interactions Arbres-Microorganismes; F-54500, Vandœuvre-lès-Nancy France
- INRA UR 1138 Biogéochimie des Ecosystèmes Forestiers, Centre INRA de Nancy; Champenoux France
- Agroparistech, Centre de Nancy; F-54000, Nancy France
| | - François Maillard
- INRA, UMR1136 Interactions Arbres-Microorganismes; F-54280, Champenoux France
- Université de Lorraine, UMR1136 Interactions Arbres-Microorganismes; F-54500, Vandœuvre-lès-Nancy France
| | - Cyrille Bach
- INRA, UMR1136 Interactions Arbres-Microorganismes; F-54280, Champenoux France
- Université de Lorraine, UMR1136 Interactions Arbres-Microorganismes; F-54500, Vandœuvre-lès-Nancy France
| | - Christian Hossann
- INRA UMR1137 Ecologie et Ecophysiologie Forestière, Centre INRA de Nancy; Champenoux France
| | - Claude Brechet
- INRA UMR1137 Ecologie et Ecophysiologie Forestière, Centre INRA de Nancy; Champenoux France
| | - Nicolas Angeli
- INRA UMR1137 Ecologie et Ecophysiologie Forestière, Centre INRA de Nancy; Champenoux France
| | - Bernhard Zeller
- INRA UR 1138 Biogéochimie des Ecosystèmes Forestiers, Centre INRA de Nancy; Champenoux France
| | - Laurent Saint-André
- INRA UR 1138 Biogéochimie des Ecosystèmes Forestiers, Centre INRA de Nancy; Champenoux France
| | - Marc Buée
- INRA, UMR1136 Interactions Arbres-Microorganismes; F-54280, Champenoux France
- Université de Lorraine, UMR1136 Interactions Arbres-Microorganismes; F-54500, Vandœuvre-lès-Nancy France
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15
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Extraction optimization, characterization, antioxidant and immunomodulatory activities of a novel polysaccharide from the wild mushroom Paxillus involutus. Int J Biol Macromol 2018; 112:326-332. [DOI: 10.1016/j.ijbiomac.2018.01.132] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/11/2018] [Accepted: 01/19/2018] [Indexed: 01/11/2023]
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16
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Beneš V, Leonhardt T, Sácký J, Kotrba P. Two P 1B-1-ATPases of Amanita strobiliformis With Distinct Properties in Cu/Ag Transport. Front Microbiol 2018; 9:747. [PMID: 29740406 PMCID: PMC5924815 DOI: 10.3389/fmicb.2018.00747] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 04/03/2018] [Indexed: 01/02/2023] Open
Abstract
As we have shown previously, the Cu and Ag concentrations in the sporocarps of Ag-hyperaccumulating Amanita strobiliformis are correlated, and both metals share the same uptake system and are sequestered by the same metallothioneins intracellularly. To further improve our knowledge of the Cu and Ag handling in A. strobiliformis cells, we searched its transcriptome for the P1B-1-ATPases, recognizing Cu+ and Ag+ for transport. We identified transcripts encoding 1097-amino acid (AA) AsCRD1 and 978-AA AsCCC2, which were further subjected to functional studies in metal sensitive Saccharomyces cerevisiae. The expression of AsCRD1 conferred highly increased Cu and Ag tolerance to metal sensitive yeasts in which the functional AsCRD1:GFP (green fluorescent protein) fusion localized exclusively to the tonoplast, indicating that the AsCRD1-mediated Cu and Ag tolerance was a result of vacuolar sequestration of the metals. Increased accumulation of AsCRD1 transcripts observed in A. strobiliformis mycelium upon the treatments with Cu and Ag (8.7- and 4.5-fold in the presence of 5 μM metal, respectively) supported the notion that AsCRD1 can be involved in protection of the A. strobiliformis cells against the toxicity of both metals. Neither Cu nor Ag affected the levels of AsCCC2 transcripts. Heterologous expression of AsCCC2 in mutant yeasts did not contribute to Cu tolerance, but complemented the mutant genotype of the S. cerevisiae ccc2Δ strain. Consistent with the role of the yeast Ccc2 in the trafficking of Cu from cytoplasm to nascent proteins via post-Golgi, the GFP fluorescence in AsCCC2-expressing ccc2Δ yeasts localized among Golgi-like punctate foci within the cells. The AsCRD1- and AsCCC2-associated phenotypes were lost in yeasts expressing mutant transporter variants in which a conserved phosphorylation/dephosphorylation site was altered. Altogether, the data support the roles of AsCRD1 and AsCCC2 as genuine P1B-1-ATPases, and indicate their important functions in the removal of toxic excess of Cu and Ag from the cytoplasm and charging the endomembrane system with Cu, respectively.
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Affiliation(s)
- Vojtěch Beneš
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Prague, Czechia
| | - Tereza Leonhardt
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Prague, Czechia
| | - Jan Sácký
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Prague, Czechia
| | - Pavel Kotrba
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Prague, Czechia
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17
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Brown Rot-Type Fungal Decomposition of Sorghum Bagasse: Variable Success and Mechanistic Implications. Int J Microbiol 2018; 2018:4961726. [PMID: 29849648 PMCID: PMC5903193 DOI: 10.1155/2018/4961726] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 02/27/2018] [Indexed: 01/19/2023] Open
Abstract
Sweet sorghum is a promising crop for a warming, drying African climate, and basic information is lacking on conversion pathways for its lignocellulosic residues (bagasse). Brown rot wood-decomposer fungi use carbohydrate-selective pathways that, when assessed on sorghum, a grass substrate, can yield information relevant to both plant biomass conversion and fungal biology. In testing sorghum decomposition by brown rot fungi (Gloeophyllum trabeum, Serpula lacrymans), we found that G. trabeum readily degraded sorghum, removing xylan prior to removing glucan. Serpula lacrymans, conversely, caused little decomposition. Ergosterol (fungal biomarker) and protein levels were similar for both fungi, but S. lacrymans produced nearly 4x lower polysaccharide-degrading enzyme specific activity on sorghum than G. trabeum, perhaps a symptom of starvation. Linking this information to genome comparisons including other brown rot fungi known to have a similar issue regarding decomposing grasses (Postia placenta, Fomitopsis pinicola) suggested that a lack of CE 1 feruloyl esterases as well as low xylanase activity in S. lacrymans (3x lower than in G. trabeum) may hinder S. lacrymans, P. placenta, and F. pinicola when degrading grass substrates. These results indicate variability in brown rot mechanisms, which may stem from a differing ability to degrade certain lignin-carbohydrate complexes.
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18
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Op De Beeck M, Troein C, Peterson C, Persson P, Tunlid A. Fenton reaction facilitates organic nitrogen acquisition by an ectomycorrhizal fungus. THE NEW PHYTOLOGIST 2018; 218:335-343. [PMID: 29297591 PMCID: PMC5873446 DOI: 10.1111/nph.14971] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/27/2017] [Indexed: 05/05/2023]
Abstract
Boreal trees rely on their ectomycorrhizal fungal symbionts to acquire growth-limiting nutrients, such as nitrogen (N), which mainly occurs as proteins complexed in soil organic matter (SOM). The mechanisms for liberating this N are unclear as ectomycorrhizal fungi have lost many genes encoding lignocellulose-degrading enzymes present in their saprotrophic ancestors. We hypothesized that hydroxyl radicals (˙ OH), produced by the ectomycorrhizal fungus Paxillus involutus during growth on SOM, are involved in liberating organic N. Paxillus involutus was grown for 7 d on N-containing or N-free substrates that represent major organic compounds of SOM. ˙ OH production, ammonium assimilation, and proteolytic activity were measured daily. ˙ OH production was strongly induced when P. involutus switched from ammonium to protein as the main N source. Extracellular proteolytic activity was initiated shortly after the oxidation. Oxidized protein substrates induced higher proteolytic activity than unmodified proteins. Dynamic modeling predicted that ˙ OH production occurs in a burst, regulated mainly by ammonium and ferric iron concentrations. We propose that the production of ˙ OH and extracellular proteolytic enzymes are regulated by similar nutritional signals. Oxidation works in concert with proteolysis, improving N liberation from proteins in SOM. Organic N mining by ectomycorrhizal fungi has, until now, only been attributed to proteolysis.
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Affiliation(s)
- Michiel Op De Beeck
- Department of BiologyMicrobial Ecology GroupLund UniversityEcology BuildingSE‐223 62LundSweden
| | - Carl Troein
- Department of Astronomy and Theoretical Physics, Computational Biology and Biological PhysicsLund UniversitySölvegatan 14ASE‐223 62LundSweden
| | - Carsten Peterson
- Department of Astronomy and Theoretical Physics, Computational Biology and Biological PhysicsLund UniversitySölvegatan 14ASE‐223 62LundSweden
| | - Per Persson
- Department of BiologyMicrobial Ecology GroupLund UniversityEcology BuildingSE‐223 62LundSweden
- Centre for Environmental and Climate Research (CEC)Lund UniversityEcology BuildingSE‐223 62LundSweden
| | - Anders Tunlid
- Department of BiologyMicrobial Ecology GroupLund UniversityEcology BuildingSE‐223 62LundSweden
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19
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Wang T, Tian Z, Bengtson P, Tunlid A, Persson P. Mineral surface-reactive metabolites secreted during fungal decomposition contribute to the formation of soil organic matter. Environ Microbiol 2017; 19:5117-5129. [PMID: 29124857 DOI: 10.1111/1462-2920.13990] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 09/27/2017] [Accepted: 10/02/2017] [Indexed: 11/27/2022]
Abstract
Soil organic matter (SOM) constitutes the largest terrestrial C pool. An emerging, untested, view is that oxidation and depolymerization of SOM by microorganisms promote the formation of SOM-mineral associations that is critical for SOM stabilization. To test this hypothesis, we performed laboratory-scale experiments involving one ectomycorrhizal and one saprotrophic fungus that represent the two major functional groups of microbial decomposers in the boreal forest soils. Fungal decomposition enhanced the retention of SOM on goethite, partly because of oxidative modifications of organic matter (OM) by the fungi. Moreover, both fungi secreted substantial amounts (> 10% new biomass C) of aromatic metabolites that also contributed to an enhanced mineral retention of OM. Our study demonstrates that soil fungi can form mineral-stabilized SOM not only by oxidative conversion of the SOM but also by synthesizing mineral surface-reactive metabolites. Metabolites produced by fungal decomposers can play a yet overlooked role in the formation and stabilization of SOM.
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Affiliation(s)
- Tao Wang
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Zhaomo Tian
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, 223 62 Lund, Sweden.,Centre for Environmental and Climate Research (CEC), Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Per Bengtson
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Anders Tunlid
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Per Persson
- Department of Biology, Microbial Ecology Group, Lund University, Ecology Building, 223 62 Lund, Sweden.,Centre for Environmental and Climate Research (CEC), Lund University, Ecology Building, 223 62 Lund, Sweden
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20
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Hendricks JJ, Mitchell RJ, Kuehn KA, Pecot SD. Ectomycorrhizal fungal mycelia turnover in a longleaf pine forest. THE NEW PHYTOLOGIST 2016; 209:1693-1704. [PMID: 26537020 DOI: 10.1111/nph.13729] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 09/25/2015] [Indexed: 06/05/2023]
Abstract
Elucidation of the patterns and controls of carbon (C) flow and nitrogen (N) cycling in forests has been hindered by a poor understanding of ectomycorrhizal fungal mycelia (EFM) dynamics. In this study, EFM standing biomass (based on soil ergosterol concentrations), production (based on ergosterol accrual in ingrowth cores), and turnover rate (the quotient of annual production and average standing biomass estimates) were assessed in a 25-yr-old longleaf pine (Pinus palustris) plantation where C flow was manipulated by foliar scorching and N fertilization for 5 yr before study initiation. In the controls, EFM standing biomass was 30 ± 7 g m(-2) , production was 279 ± 63 g m(-2) yr(-1) , and turnover rate was 10 ± 3 times yr(-1) . The scorched × fertilized treatment had significantly higher EFM standing biomass (38 ± 8 g m(-2) ), significantly lower production (205 ± 28 g m(-2) yr(-1) ), and a trend of decreased turnover rate (6 ± 1 times yr(-1) ). The EFM turnover estimates, which are among the first reported for natural systems, indicate that EFM are a dynamic component of ecosystems, and that conventional assessments have probably underestimated the role of EFM in C flow and nutrient cycling.
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Affiliation(s)
- Joseph J Hendricks
- Department of Biology, University of West Georgia, 1601 Maple Street, Carrollton, GA, 30118, USA
| | - Robert J Mitchell
- Joseph W. Jones Ecological Research Center at Ichauway, 3988 Jones Center Drive, Newton, GA, 39870, USA
| | - Kevin A Kuehn
- Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive, Hattiesburg, MS, 39406, USA
| | - Stephen D Pecot
- Joseph W. Jones Ecological Research Center at Ichauway, 3988 Jones Center Drive, Newton, GA, 39870, USA
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