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Khrennikov A, Iryama S, Basieva I, Sato K. Quantum-like environment adaptive model for creation of phenotype. Biosystems 2024; 242:105261. [PMID: 38964651 DOI: 10.1016/j.biosystems.2024.105261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 06/26/2024] [Accepted: 06/26/2024] [Indexed: 07/06/2024]
Abstract
The textbook conceptualization of phenotype creation, "genotype (G) + environment (E) + genotype & environment interactions (GE) ↦ phenotype (Ph)", is modeled with open quantum systems theory (OQST) or more generally with adaptive dynamics theory (ADT). The model is quantum-like, i.e., it is not about quantum physical processes in biosystems. Generally such modeling is about applications of the quantum formalism and methodology outside of physics. Macroscopic biosystems, in our case genotypes and phenotypes, are treated as information processors which functioning matches the laws of quantum information theory. Phenotypes are the outputs of the E-adaptation processes described by the quantum master equation, Gorini-Kossakowski-Sudarshan-Lindblad equation (GKSL). Its stationary states correspond to phenotypes. We highlight the class of GKSL dynamics characterized by the camel-like graphs of (von Neumann) entropy: in the process of E-adaptation phenotype's state entropy (disorder) first increases and then falls down - a stable and well-ordered phenotype is created. Traits, an organism's phenotypic characteristics, are modeled within the quantum measurement theory, as generally unsharp observables given by positive operator valued measures (POVMs. This paper is also a review on the methods and mathematical apparatus of quantum information biology.
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Affiliation(s)
- Andrei Khrennikov
- Linnaeus University, International Center for Mathematical Modeling in Physics and Cognitive Sciences Växjö, SE-351 95, Sweden.
| | - Satoshi Iryama
- Tokyo University of Science, Faculty of Science and Technology, Department of Information Sciences, Noda City, Chiba 278-8510, Japan
| | - Irina Basieva
- Linnaeus University, International Center for Mathematical Modeling in Physics and Cognitive Sciences Växjö, SE-351 95, Sweden
| | - Keiko Sato
- Tokyo University of Science, Faculty of Science and Technology, Department of Information Sciences, Noda City, Chiba 278-8510, Japan
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2
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Abdoli P, Vulin C, Lepiz M, Chase AB, Weihe C, Rodríguez-Verdugo A. Substrate complexity buffers negative interactions in a synthetic community of leaf litter degraders. FEMS Microbiol Ecol 2024; 100:fiae102. [PMID: 39020097 PMCID: PMC11289631 DOI: 10.1093/femsec/fiae102] [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: 01/13/2024] [Revised: 07/02/2024] [Accepted: 07/16/2024] [Indexed: 07/19/2024] Open
Abstract
Leaf litter microbes collectively degrade plant polysaccharides, influencing land-atmosphere carbon exchange. An open question is how substrate complexity-defined as the structure of the saccharide and the amount of external processing by extracellular enzymes-influences species interactions. We tested the hypothesis that monosaccharides (i.e. xylose) promote negative interactions through resource competition, and polysaccharides (i.e. xylan) promote neutral or positive interactions through resource partitioning or synergism among extracellular enzymes. We assembled a three-species community of leaf litter-degrading bacteria isolated from a grassland site in Southern California. In the polysaccharide xylan, pairs of species stably coexisted and grew equally in coculture and in monoculture. Conversely, in the monosaccharide xylose, competitive exclusion and negative interactions prevailed. These pairwise dynamics remained consistent in a three-species community: all three species coexisted in xylan, while only two species coexisted in xylose, with one species capable of using peptone. A mathematical model showed that in xylose these dynamics could be explained by resource competition. Instead, the model could not predict the coexistence patterns in xylan, suggesting other interactions exist during biopolymer degradation. Overall, our study shows that substrate complexity influences species interactions and patterns of coexistence in a synthetic microbial community of leaf litter degraders.
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Affiliation(s)
- Parmis Abdoli
- Department of Ecology and Evolutionary Biology, University of California Irvine, 321 Steinhaus Hall, Irvine, CA 92697, United States
| | - Clément Vulin
- Department of Fundamental Microbiology, University of Lausanne, Biophore, CH-1015 Lausanne, Switzerland
| | - Miriam Lepiz
- Department of Ecology and Evolutionary Biology, University of California Irvine, 321 Steinhaus Hall, Irvine, CA 92697, United States
| | - Alexander B Chase
- Department of Earth Sciences, Southern Methodist University, 3225 Daniel Avenue, Suite 207, Heroy Hall, Dallas, TX 75205, United States
| | - Claudia Weihe
- Department of Ecology and Evolutionary Biology, University of California Irvine, 321 Steinhaus Hall, Irvine, CA 92697, United States
| | - Alejandra Rodríguez-Verdugo
- Department of Ecology and Evolutionary Biology, University of California Irvine, 321 Steinhaus Hall, Irvine, CA 92697, United States
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Bautista-Cruz A, Aquino-Bolaños T, Hernández-Canseco J, Quiñones-Aguilar EE. Cellulolytic Aerobic Bacteria Isolated from Agricultural and Forest Soils: An Overview. BIOLOGY 2024; 13:102. [PMID: 38392320 PMCID: PMC10886624 DOI: 10.3390/biology13020102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/24/2024]
Abstract
This review provides insights into cellulolytic bacteria present in global forest and agricultural soils over a period of 11 years. It delves into the study of soil-dwelling cellulolytic bacteria and the enzymes they produce, cellulases, which are crucial in both soil formation and the carbon cycle. Forests and agricultural activities are significant contributors to the production of lignocellulosic biomass. Forest ecosystems, which are key carbon sinks, contain 20-30% cellulose in their leaf litter. Concurrently, the agricultural sector generates approximately 998 million tons of lignocellulosic waste annually. Predominant genera include Bacillus, Pseudomonas, Stenotrophomonas, and Streptomyces in forests and Bacillus, Streptomyces, Pseudomonas, and Arthrobacter in agricultural soils. Selection of cellulolytic bacteria is based on their hydrolysis ability, using artificial cellulose media and dyes like Congo red or iodine for detection. Some studies also measure cellulolytic activity in vitro. Notably, bacterial cellulose hydrolysis capability may not align with their cellulolytic enzyme production. Enzymes such as GH1, GH3, GH5, GH6, GH8, GH9, GH10, GH12, GH26, GH44, GH45, GH48, GH51, GH74, GH124, and GH148 are crucial, particularly GH48 for crystalline cellulose degradation. Conversely, bacteria with GH5 and GH9 often fail to degrade crystalline cellulose. Accurate identification of cellulolytic bacteria necessitates comprehensive genomic analysis, supplemented by additional proteomic and transcriptomic techniques. Cellulases, known for degrading cellulose, are also significant in healthcare, food, textiles, bio-washing, bleaching, paper production, ink removal, and biotechnology, emphasizing the importance of discovering novel cellulolytic strains in soil.
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Affiliation(s)
- Angélica Bautista-Cruz
- Instituto Politécnico Nacional, CIIDIR-Oaxaca, Hornos 1003, Santa Cruz Xoxocotlán 71230, Oaxaca, Mexico
| | - Teodulfo Aquino-Bolaños
- Instituto Politécnico Nacional, CIIDIR-Oaxaca, Hornos 1003, Santa Cruz Xoxocotlán 71230, Oaxaca, Mexico
| | - Jessie Hernández-Canseco
- Doctoral Programme in Conservation and Use of Natural Resources, Instituto Politécnico Nacional, CIIDIR-Oaxaca, Hornos 1003, Santa Cruz Xoxocotlán 71230, Oaxaca, Mexico
| | - Evangelina Esmeralda Quiñones-Aguilar
- Laboratorio de Fitopatología de Biotecnología Vegetal, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C. Camino Arenero 1227, El Bajío del Arenal, Zapopan 45019, Jalisco, Mexico
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Barbour KM, Martiny JBH. Investigating eco-evolutionary processes of microbial community assembly in the wild using a model leaf litter system. THE ISME JOURNAL 2024; 18:wrae043. [PMID: 38506671 PMCID: PMC11008689 DOI: 10.1093/ismejo/wrae043] [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: 02/13/2024] [Accepted: 03/19/2024] [Indexed: 03/21/2024]
Abstract
Microbial communities are not the easiest to manipulate experimentally in natural ecosystems. However, leaf litter-topmost layer of surface soil-is uniquely suitable to investigate the complexities of community assembly. Here, we reflect on over a decade of collaborative work to address this topic using leaf litter as a model system in Southern California ecosystems. By leveraging a number of methodological advantages of the system, we have worked to demonstrate how four processes-selection, dispersal, drift, and diversification-contribute to bacterial and fungal community assembly and ultimately impact community functioning. Although many dimensions remain to be investigated, our initial results demonstrate that both ecological and evolutionary processes occur simultaneously to influence microbial community assembly. We propose that the development of additional and experimentally tractable microbial systems will be enormously valuable to test the role of eco-evolutionary processes in natural settings and their implications in the face of rapid global change.
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Affiliation(s)
- Kristin M Barbour
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, United States
| | - Jennifer B H Martiny
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, United States
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Likar M, Grašič M, Stres B, Regvar M, Gaberščik A. Metagenomics reveals effects of fluctuating water conditions on functional pathways in plant litter microbial community. Sci Rep 2023; 13:21741. [PMID: 38066117 PMCID: PMC10709317 DOI: 10.1038/s41598-023-49044-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 12/04/2023] [Indexed: 12/18/2023] Open
Abstract
Climate change modifies environmental conditions, resulting in altered precipitation patterns, moisture availability and nutrient distribution for microbial communities. Changes in water availability are projected to affect a range of ecological processes, including the decomposition of plant litter and carbon cycling. However, a detailed understanding of microbial stress response to drought/flooding is missing. In this study, an intermittent lake is taken up as a model for changes in water availability and how they affect the functional pathways in microbial communities of the decomposing Phragmites australis litter. The results show that most enriched functions in both habitats belonged to the classes of Carbohydrates and Clustering-based subsystems (terms with unknown function) from SEED subsystems classification. We confirmed that changes in water availability resulted in altered functional makeup of microbial communities. Our results indicate that microbial communities under more frequent water stress (due to fluctuating conditions) could sustain an additional metabolic cost due to the production or uptake of compatible solutes to maintain cellular osmotic balance. Nevertheless, although prolonged submergence seemed to have a negative impact on several functional traits in the fungal community, the decomposition rate was not affected.
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Affiliation(s)
- Matevž Likar
- Biotechnical Faculty, Department of Biology, University of Ljubljana, Večna Pot 111, 1000, Ljubljana, Slovenia.
| | - Mateja Grašič
- Biotechnical Faculty, Department of Biology, University of Ljubljana, Večna Pot 111, 1000, Ljubljana, Slovenia
| | - Blaž Stres
- Institute of Sanitary Engineering, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia
- Biocybernetics and Robotics, Department of Automation, Jožef Stefan Institute, Ljubljana, Slovenia
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Ljubljana, Slovenia
| | - Marjana Regvar
- Biotechnical Faculty, Department of Biology, University of Ljubljana, Večna Pot 111, 1000, Ljubljana, Slovenia
| | - Alenka Gaberščik
- Biotechnical Faculty, Department of Biology, University of Ljubljana, Večna Pot 111, 1000, Ljubljana, Slovenia
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Zhang L, Li J, Wang Z, Zhang D, Liu H, Wang J, Wu F, Wang X, Zhou X. Litter mixing promoted decomposition and altered microbial community in common bean root litter. BMC Microbiol 2023; 23:148. [PMID: 37217839 DOI: 10.1186/s12866-023-02871-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
BACKGROUND Decomposition of plant litter is a key driver of carbon and nutrient cycling in terrestrial ecosystems. Mixing litters of different plant species may alter the decomposition rate, but its effect on the microbial decomposer community in plant litter is not fully understood. Here, we tested the effects of mixing with maize (Zea mays L.) and soybean [Glycine max (Linn.) Merr.] stalk litters on the decomposition and microbial decomposer communities of common bean (Phaseolus vulgaris L.) root litter at the early decomposition stage in a litterbag experiment. RESULTS Mixing with maize stalk litter, soybean stalk litter, and both of these litters increased the decomposition rate of common bean root litter at 56 day but not 14 day after incubation. Litter mixing also increased the decomposition rate of the whole liter mixture at 56 day after incubation. Amplicon sequencing found that litter mixing altered the composition of bacterial (at 56 day after incubation) and fungal communities (at both 14 and 56 day after incubation) in common bean root litter. Litter mixing increased the abundance and alpha diversity of fungal communities in common bean root litter at 56 day after incubation. Particularly, litter mixing stimulated certain microbial taxa, such as Fusarium, Aspergillus and Stachybotrys spp. In addition, a pot experiment with adding litters in the soil showed that litter mixing promoted growth of common bean seedlings and increased soil nitrogen and phosphorus contents. CONCLUSIONS This study showed that litter mixing can promote the decomposition rate and cause shifts in microbial decomposer communities, which may positively affect crop growth.
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Affiliation(s)
- Linlin Zhang
- Department of Horticulture, Northeast Agricultural University, Harbin, China
| | - Jiawei Li
- Department of Horticulture, Northeast Agricultural University, Harbin, China
| | - Zhilin Wang
- Department of Horticulture, Northeast Agricultural University, Harbin, China
| | - Dinghong Zhang
- Department of Horticulture, Northeast Agricultural University, Harbin, China
| | - Hui Liu
- Department of Horticulture, Northeast Agricultural University, Harbin, China
| | - Jia Wang
- Department of Horticulture, Northeast Agricultural University, Harbin, China
| | - Fengzhi Wu
- Department of Horticulture, Northeast Agricultural University, Harbin, China
| | - Xue Wang
- Northeast Agricultural University Library, Northeast Agricultural University, Harbin, China.
| | - Xingang Zhou
- Department of Horticulture, Northeast Agricultural University, Harbin, China.
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, China.
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Wang Y, Zhang X, Lou Z, An X, Li X, Jiang X, Wang W, Zhao H, Fu M, Cui Z. The effects of adding exogenous lignocellulose degrading bacteria during straw incorporation in cold regions on degradation characteristics and soil indigenous bacteria communities. Front Microbiol 2023; 14:1141545. [PMID: 37234521 PMCID: PMC10206022 DOI: 10.3389/fmicb.2023.1141545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 04/21/2023] [Indexed: 05/28/2023] Open
Abstract
Low temperature is one of the bottleneck factors that limits the degradation of straw during rice straw incorporation. Determining strategies to promote the efficient degradation of straw in cold regions has become a highly active research area. This study was to investigate the effect of rice straw incorporation by adding exogenous lignocellulose decomposition microbial consortiums at different soil depths in cold regions. The results showed that the lignocellulose was degraded the most efficiently during straw incorporation, which was in deep soil with the full addition of a high-temperature bacterial system. The composite bacterial systems changed the indigenous soil microbial community structure and diminished the effect of straw incorporation on soil pH, it also significantly increased rice yield and effectively enhanced the functional abundance of soil microorganisms. The predominant bacteria SJA-15, Gemmatimonadaceae, and Bradyrhizobium promoted straw degradation. The concentration of bacterial system and the depth of soil had significantly positive correlations on lignocellulose degradation. These results provide new insights and a theoretical basis for the changes in the soil microbial community and the application of lignocellulose-degrading composite microbial systems with straw incorporation in cold regions.
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Affiliation(s)
- Yunlong Wang
- College of Agronomy, Yanbian University, Yanji, China
| | - Xuelian Zhang
- College of Agronomy, Yanbian University, Yanji, China
| | - Zixi Lou
- College of Agronomy, Yanbian University, Yanji, China
| | - Xiaoya An
- College of Agronomy, Yanbian University, Yanji, China
| | - Xue Li
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Xinbo Jiang
- College of Agronomy, Yanbian University, Yanji, China
| | - Weidong Wang
- Heilongjiang Bayi Agricultural University, Daqing, China
| | - Hongyan Zhao
- College of Agronomy, Yanbian University, Yanji, China
| | - Minjie Fu
- College of Agronomy, Yanbian University, Yanji, China
| | - Zongjun Cui
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
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Kimeklis AK, Gladkov GV, Orlova OV, Afonin AM, Gribchenko ES, Aksenova TS, Kichko AA, Pinaev AG, Andronov EE. The Succession of the Cellulolytic Microbial Community from the Soil during Oat Straw Decomposition. Int J Mol Sci 2023; 24:ijms24076342. [PMID: 37047311 PMCID: PMC10094526 DOI: 10.3390/ijms24076342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/24/2023] [Accepted: 03/27/2023] [Indexed: 03/30/2023] Open
Abstract
The process of straw decomposition is dynamic and is accompanied by the succession of the microbial decomposing community, which is driven by poorly understood interactions between microorganisms. Soil is a complex ecological niche, and the soil microbiome can serve as a source of potentially active cellulolytic microorganisms. Here, we performed an experiment on the de novo colonization of oat straw by the soil microbial community by placing nylon bags with sterilized oat straw in the pots filled with chernozem soil and incubating them for 6 months. The aim was to investigate the changes in decomposer microbiota during this process using conventional sequencing techniques. The bacterial succession during straw decomposition occurred in three phases: the early phase (first month) was characterized by high microbial activity and low diversity, the middle phase (second to third month) was characterized by low activity and low diversity, and the late phase (fourth to sixth months) was characterized by low activity and high diversity. Analysis of amplicon sequencing data revealed three groups of co-changing phylotypes corresponding to these phases. The early active phase was abundant in the cellulolytic members from Pseudomonadota, Bacteroidota, Bacillota, and Actinobacteriota for bacteria and Ascomycota for fungi, and most of the primary phylotypes were gone by the end of the phase. The second intermediate phase was marked by the set of phylotypes from the same phyla persisting in the community. In the mature community of the late phase, apart from the core phylotypes, non-cellulolytic members from Bdellovibrionota, Myxococcota, Chloroflexota, and Thermoproteota appeared. Full metagenome sequencing of the microbial community from the end of the middle phase confirmed that major bacterial and fungal members of this consortium had genes of glycoside hydrolases (GH) connected to cellulose and chitin degradation. The real-time analysis of the selection of these genes showed that their representation varied between phases, and this occurred under the influence of the host, and not the GH family factor. Our findings demonstrate that soil microbial community may act as an efficient source of cellulolytic microorganisms and that colonization of the cellulolytic substrate occurs in several phases, each characterized by its own taxonomic and functional profile.
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Affiliation(s)
- Anastasiia K. Kimeklis
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
- Department of Applied Ecology, Saint-Petersburg State University, 199034 Saint Petersburg, Russia
- Correspondence: (A.K.K.); (E.E.A.)
| | - Grigory V. Gladkov
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Olga V. Orlova
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Alexey M. Afonin
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211 Kuopio, Finland
| | - Emma S. Gribchenko
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Tatiana S. Aksenova
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Arina A. Kichko
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Alexander G. Pinaev
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Evgeny E. Andronov
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
- Dokuchaev Soil Science Institute, 119017 Moscow, Russia
- Correspondence: (A.K.K.); (E.E.A.)
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Allison SD. Microbial drought resistance may destabilize soil carbon. Trends Microbiol 2023:S0966-842X(23)00078-1. [PMID: 37059647 DOI: 10.1016/j.tim.2023.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/09/2023] [Accepted: 03/02/2023] [Indexed: 04/16/2023]
Abstract
Droughts are becoming more frequent and intense with climate change. As plants and microbes respond to drought, there may be consequences for the vast stocks of organic carbon stored in soils. If microbes sustain their activity under drought, soils could lose carbon, especially if inputs from plants decline. Empirical and theoretical studies reveal multiple mechanisms of microbial drought resistance, including tolerance and avoidance. Physiological responses allow microbes to acclimate to drought within minutes to days. Along with dispersal, shifts in community composition could allow microbiomes to maintain functioning despite drought. Microbes might also adapt to drier conditions through evolutionary processes. Together, these mechanisms could result in soil carbon losses larger than currently anticipated under climate change.
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Affiliation(s)
- Steven D Allison
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA; Department of Earth System Science, University of California, Irvine, CA, USA.
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10
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Pisa JH, Hero JS, Romero HG, Martínez MA. A genome-proteome-based approach for xylan degradation by Cohnella sp. AR92. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:755-765. [PMID: 35940859 DOI: 10.1111/1758-2229.13113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Several members of Cohnella genus have been reported as xylanolytic bacteria with significant capacity as carbohydrate-active enzyme producers (CAZymes), whose mechanisms involving xylan degradation are a key goal for suitable applications in bio-based industries. Using Cohnella sp. AR92 bacterium, we ensembled a genomic-proteomic approach to assess plant biomass conversion targeting its xylanolytic set of enzymes. Also, the genomic traits of the strain AR92 were compared to other Cohnella spp., showing a significant variability in terms of genome sizes and content of genes that code CAZymes. The AR92 strain genome harbours 209 CAZymes encoding sequences active on different polysaccharides, particularly directed towards xylans. Concurrent proteomic data recovered from cultures containing three kinds of lignocellulosic-derived substrates showed a broad set of xylan-degrading enzymes. The most abundant CAZymes expressed in the different conditions assayed were endo-β-1,4-xylanases belonging to the GH11 and GH10 families, enzymes that were previously proved to be useful in the biotransformation of lignocellulosic biomass derived from sugarcane as well as onto xylan-enriched substrates. Therefore, considering the large reserve of CAZymes of Cohnella sp. AR92, a xylan processing model for AR92 strain is proposed.
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Affiliation(s)
- José Horacio Pisa
- PROIMI - CONICET (National Scientific and Technical Research Council), Tucumán, Argentina
| | - Johan Sebastian Hero
- PROIMI - CONICET (National Scientific and Technical Research Council), Tucumán, Argentina
| | - Héctor Gabriel Romero
- Department of Ecology and Evolution, Faculty of Sciences/CURE, University of the Republic, Montevideo, Uruguay
| | - María Alejandra Martínez
- PROIMI - CONICET (National Scientific and Technical Research Council), Tucumán, Argentina
- Faculty of Exact Sciences and Technology, National University of Tucuman, Tucumán, Argentina
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11
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Palit K, Rath S, Chatterjee S, Das S. Microbial diversity and ecological interactions of microorganisms in the mangrove ecosystem: Threats, vulnerability, and adaptations. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:32467-32512. [PMID: 35182344 DOI: 10.1007/s11356-022-19048-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
Mangroves are among the world's most productive ecosystems and a part of the "blue carbon" sink. They act as a connection between the terrestrial and marine ecosystems, providing habitat to countless organisms. Among these, microorganisms (e.g., bacteria, archaea, fungi, phytoplankton, and protozoa) play a crucial role in this ecosystem. Microbial cycling of major nutrients (carbon, nitrogen, phosphorus, and sulfur) helps maintain the high productivity of this ecosystem. However, mangrove ecosystems are being disturbed by the increasing concentration of greenhouse gases within the atmosphere. Both the anthropogenic and natural factors contribute to the upsurge of greenhouse gas concentration, resulting in global warming. Changing climate due to global warming and the increasing rate of human interferences such as pollution and deforestation are significant concerns for the mangrove ecosystem. Mangroves are susceptible to such environmental perturbations. Global warming, human interventions, and its consequences are destroying the ecosystem, and the dreadful impacts are experienced worldwide. Therefore, the conservation of mangrove ecosystems is necessary for protecting them from the changing environment-a step toward preserving the globe for better living. This review highlights the importance of mangroves and their microbial components on a global scale and the degree of vulnerability of the ecosystems toward anthropic and climate change factors. The future scenario of the mangrove ecosystem and the resilience of plants and microbes have also been discussed.
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Affiliation(s)
- Krishna Palit
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India
| | - Sonalin Rath
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India
| | - Shreosi Chatterjee
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India
| | - Surajit Das
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India.
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12
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De Novo Metagenomic Analysis of Microbial Community Contributing in Lignocellulose Degradation in Humus Samples Harvested from Cuc Phuong Tropical Forest in Vietnam. DIVERSITY 2022. [DOI: 10.3390/d14030220] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We aimed to investigate the microbial diversity, mine lignocellulose-degrading enzymes/proteins, and analyze the domain structures of the mined enzymes/proteins in humus samples collected from the Cuc Phuong National Park, Vietnam. Using a high-throughput Illumina sequencer, 52 Gbs of microbial DNA were assembled in 2,611,883 contigs, from which 4,104,872 open reading frames (ORFs) were identified. Among the total microbiome analyzed, bacteria occupied 99.69%; the five ubiquitous bacterial phyla included Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, and Acidobacteria, which accounted for 92.59%. Proteobacteria (75.68%), the most dominant, was 5.77 folds higher than the second abundant phylum Bacteroidetes (13.11%). Considering the enzymes/proteins involved in lignocellulose degradation, 22,226 ORFs were obtained from the annotation analysis using a KEGG database. The estimated ratio of Proteobacteria/Bacteroidetes was approximately 1:1 for pretreatment and hemicellulases groups and 2.4:1 for cellulases. Furthermore, analysis of domain structures revealed their diversity in lignocellulose-degrading enzymes. CE and PL were two main families in pretreatment; GH1 and GH3-FN3 were the highest domains in the cellulase group, whereas GH2 and GH43 represented the hemicellulase group. These results validate that natural tropical forest soil could be considered as an important source to explore bacteria and novel enzymes/proteins for the degradation of lignocellulose.
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Evans S, Allison S, Hawkes C. Microbes, memory, and moisture: predicting microbial moisture responses and their impact on carbon cycling. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14034] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sarah Evans
- W.K. Kellogg Biological Station, Ecology and Evolutionary Biology Program Department of Integrative Biology Michigan State University Hickory Corners MI 49083 USA
| | - Steve Allison
- Department of Ecology and Evolutionary Biology Department of Earth System Science University of California Irvine California 92697 USA
| | - Christine Hawkes
- Department of Plant and Microbial Biology North Carolina State University Raleigh NC 27607 USA
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Phylosymbiosis in the Rhizosphere Microbiome Extends to Nitrogen Cycle Functional Potential. Microorganisms 2021; 9:microorganisms9122476. [PMID: 34946078 PMCID: PMC8709245 DOI: 10.3390/microorganisms9122476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 12/04/2022] Open
Abstract
Most plants rely on specialized root-associated microbes to obtain essential nitrogen (N), yet not much is known about the evolutionary history of the rhizosphere–plant interaction. We conducted a common garden experiment to investigate the plant root–rhizosphere microbiome association using chloridoid grasses sampled from around the world and grown from seed in a greenhouse. We sought to test whether plants that are more closely related phylogenetically have more similar root bacterial microbiomes than plants that are more distantly related. Using metagenome sequencing, we found that there is a conserved core and a variable rhizosphere bacterial microbiome across the chloridoid grasses. Additionally, phylogenetic distance among the host plant species was correlated with bacterial community composition, suggesting the plant hosts prefer specific bacterial lineages. The functional potential for N utilization across microbiomes fluctuated extensively and mirrored variation in the microbial community composition across host plants. Variation in the bacterial potential for N fixation was strongly affected by the host plants’ phylogeny, whereas variation in N recycling, nitrification, and denitrification was unaffected. This study highlights the evolutionary linkage between the N fixation traits of the microbial community and the plant host and suggests that not all functional traits are equally important for plant–microbe associations.
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Bei Q, Moser G, Müller C, Liesack W. Seasonality affects function and complexity but not diversity of the rhizosphere microbiome in European temperate grassland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 784:147036. [PMID: 33895508 DOI: 10.1016/j.scitotenv.2021.147036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 04/04/2021] [Accepted: 04/05/2021] [Indexed: 06/12/2023]
Abstract
Knowledge on how grassland microbiota responds on gene expression level to winter-summer change of seasons is poor. Here, we used a combination of quantitative PCR-based assays and metatranscriptomics to assess the impact of seasonality on the rhizospheric microbiota in temperate European grassland. Bacteria dominated, being at least one order of magnitude more abundant than fungi. Despite a fivefold summer increase in bacterial community size, season had nearly no effect on microbiome diversity. It, however, had a marked impact on taxon-specific gene expression, with 668 genes significantly differing in relative transcript abundance between winter and summer samples. Acidobacteria, Bacteroidetes, Planctomycetes, and Proteobacteria showed a greater relative gene expression activity in winter, while mRNA of Actinobacteria and Fungi was, relative to other taxa, significantly enriched in summer. On functional level, mRNA involved in protein turnover (e.g., transcription and translation) and cell maintenance (e.g., chaperones that protect against cell freezing damage such as GroEL and Hsp20) were highly enriched in winter. By contrast, mRNA involved in central carbon and amino acid metabolisms had a greater abundance in summer. Among carbohydrate-active enzymes, transcripts of GH36 family (hemicellulases) were highly enriched in winter, while those encoding GH3 family (cellulases) showed increased abundance in summer. The seasonal differences in plant polymer breakdown were linked to a significantly greater microbial network complexity in winter than in summer. Conceptually, the winter-summer change in microbiome functioning can be well explained by a shift from stress-tolerator to high-yield life history strategy.
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Affiliation(s)
- Qicheng Bei
- Research Group Methanotrophic Bacteria, and Environmental Genomics/Transcriptomics Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany.
| | - Gerald Moser
- Department of Plant Ecology, Justus Liebig University Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany
| | - Christoph Müller
- Department of Plant Ecology, Justus Liebig University Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany; School of Biology and Environmental Science, University College Dublin, Ireland
| | - Werner Liesack
- Research Group Methanotrophic Bacteria, and Environmental Genomics/Transcriptomics Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany.
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Djemiel C, Goulas E, Badalato N, Chabbert B, Hawkins S, Grec S. Targeted Metagenomics of Retting in Flax: The Beginning of the Quest to Harness the Secret Powers of the Microbiota. Front Genet 2020; 11:581664. [PMID: 33193706 PMCID: PMC7652851 DOI: 10.3389/fgene.2020.581664] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/21/2020] [Indexed: 12/13/2022] Open
Abstract
The mechanical and chemical properties of natural plant fibers are determined by many different factors, both intrinsic and extrinsic to the plant, during growth but also after harvest. A better understanding of how all these factors exert their effect and how they interact is necessary to be able to optimize fiber quality for use in different industries. One important factor is the post-harvest process known as retting, representing the first step in the extraction of bast fibers from the stem of species such as flax and hemp. During this process microorganisms colonize the stem and produce hydrolytic enzymes that target cell wall polymers thereby facilitating the progressive destruction of the stem and fiber bundles. Recent advances in sequencing technology have allowed researchers to implement targeted metagenomics leading to a much better characterization of the microbial communities involved in retting, as well as an improved understanding of microbial dynamics. In this paper we review how our current knowledge of the microbiology of retting has been improved by targeted metagenomics and discuss how related '-omics' approaches might be used to fully characterize the functional capability of the retting microbiome.
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Affiliation(s)
- Christophe Djemiel
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Estelle Goulas
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Nelly Badalato
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Brigitte Chabbert
- Université de Reims Champagne Ardenne, INRAE, UMR FARE A 614, Reims, France
| | - Simon Hawkins
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Sébastien Grec
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
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Drought and plant litter chemistry alter microbial gene expression and metabolite production. ISME JOURNAL 2020; 14:2236-2247. [PMID: 32444813 PMCID: PMC7608424 DOI: 10.1038/s41396-020-0683-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 05/05/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022]
Abstract
Drought represents a significant stress to microorganisms and is known to reduce microbial activity and organic matter decomposition in Mediterranean ecosystems. However, we lack a detailed understanding of the drought stress response of microbial decomposers. Here we present metatranscriptomic and metabolomic data on the physiological response of in situ microbial communities on plant litter to long-term drought in Californian grass and shrub ecosystems. We hypothesised that drought causes greater microbial allocation to stress tolerance relative to growth pathways. In grass litter, communities from the decade-long ambient and reduced precipitation treatments had distinct taxonomic and functional profiles. The most discernable physiological signatures of drought were production or uptake of compatible solutes to maintain cellular osmotic balance, and synthesis of capsular and extracellular polymeric substances as a mechanism to retain water. The results show a clear functional response to drought in grass litter communities with greater allocation to survival relative to growth that could affect decomposition under drought. In contrast, communities on chemically more diverse and complex shrub litter had smaller physiological differences in response to long-term drought but higher investment in resource acquisition traits across precipitation treatments, suggesting that the functional response to drought is constrained by substrate quality. Our findings suggest, for the first time in a field setting, a trade off between microbial drought stress tolerance, resource acquisition and growth traits in plant litter microbial communities.
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Garcia MO, Templer PH, Sorensen PO, Sanders-DeMott R, Groffman PM, Bhatnagar JM. Soil Microbes Trade-Off Biogeochemical Cycling for Stress Tolerance Traits in Response to Year-Round Climate Change. Front Microbiol 2020; 11:616. [PMID: 32477275 PMCID: PMC7238748 DOI: 10.3389/fmicb.2020.00616] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/19/2020] [Indexed: 01/16/2023] Open
Abstract
Winter air temperatures are rising faster than summer air temperatures in high-latitude forests, increasing the frequency of soil freeze/thaw events in winter. To determine how climate warming and soil freeze/thaw cycles affect soil microbial communities and the ecosystem processes they drive, we leveraged the Climate Change across Seasons Experiment (CCASE) at the Hubbard Brook Experimental Forest in the northeastern United States, where replicate field plots receive one of three climate treatments: warming (+5°C above ambient in the growing season), warming in the growing season + winter freeze/thaw cycles (+5°C above ambient +4 freeze/thaw cycles during winter), and no treatment. Soil samples were taken from plots at six time points throughout the growing season and subjected to amplicon (rDNA) and metagenome sequencing. We found that soil fungal and bacterial community composition were affected by changes in soil temperature, where the taxonomic composition of microbial communities shifted more with the combination of growing-season warming and increased frequency of soil freeze/thaw cycles in winter than with warming alone. Warming increased the relative abundance of brown rot fungi and plant pathogens but decreased that of arbuscular mycorrhizal fungi, all of which recovered under combined growing-season warming and soil freeze/thaw cycles in winter. The abundance of animal parasites increased significantly under combined warming and freeze/thaw cycles. We also found that warming and soil freeze/thaw cycles suppressed bacterial taxa with the genetic potential for carbon (i.e., cellulose) decomposition and soil nitrogen cycling, such as N fixation and the final steps of denitrification. These new soil communities had higher genetic capacity for stress tolerance and lower genetic capacity to grow or reproduce, relative to the communities exposed to warming in the growing season alone. Our observations suggest that initial suppression of biogeochemical cycling with year-round climate change may be linked to the emergence of taxa that trade-off growth for stress tolerance traits.
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Affiliation(s)
- Maria O. Garcia
- Department of Biology, Boston University, Boston, MA, United States
| | | | - Patrick O. Sorensen
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Rebecca Sanders-DeMott
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Peter M. Groffman
- Advanced Science Research Center at the Graduate Center, City University of New York, New York, NY, United States
- Cary Institute of Ecosystem Studies, Millbrook, NY, United States
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Malik AA, Martiny JBH, Brodie EL, Martiny AC, Treseder KK, Allison SD. Defining trait-based microbial strategies with consequences for soil carbon cycling under climate change. THE ISME JOURNAL 2020; 14:1-9. [PMID: 31554911 PMCID: PMC6908601 DOI: 10.1038/s41396-019-0510-0] [Citation(s) in RCA: 263] [Impact Index Per Article: 65.8] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 06/07/2019] [Accepted: 08/16/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Ashish A Malik
- Department of Ecology & Evolutionary Biology, University of California, Irvine, CA, USA.
| | - Jennifer B H Martiny
- Department of Ecology & Evolutionary Biology, University of California, Irvine, CA, USA
| | - Eoin L Brodie
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Adam C Martiny
- Department of Ecology & Evolutionary Biology, University of California, Irvine, CA, USA
- Department of Earth System Science, University of California, Irvine, CA, USA
| | - Kathleen K Treseder
- Department of Ecology & Evolutionary Biology, University of California, Irvine, CA, USA
| | - Steven D Allison
- Department of Ecology & Evolutionary Biology, University of California, Irvine, CA, USA
- Department of Earth System Science, University of California, Irvine, CA, USA
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20
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Zhang X, Ma B, Liu J, Chen X, Li S, Su E, Gao L, Li H. β-Glucosidase genes differentially expressed during composting. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:174. [PMID: 33088344 PMCID: PMC7570026 DOI: 10.1186/s13068-020-01813-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 10/07/2020] [Indexed: 05/06/2023]
Abstract
BACKGROUND Cellulose degradation by cellulase is brought about by complex communities of interacting microorganisms, which significantly contribute to the cycling of carbon on a global scale. β-Glucosidase (BGL) is the rate-limiting enzyme in the cellulose degradation process. Thus, analyzing the expression of genes involved in cellulose degradation and regulation of BGL gene expression during composting will improve the understanding of the cellulose degradation mechanism. Based on our previous research, we hypothesized that BGL-producing microbial communities differentially regulate the expression of glucose-tolerant BGL and non-glucose-tolerant BGL to adapt to the changes in cellulose degradation conditions. RESULTS To confirm this hypothesis, the structure and function of functional microbial communities involved in cellulose degradation were investigated by metatranscriptomics and a DNA library search of the GH1 family of BGLs involved in natural and inoculated composting. Under normal conditions, the group of non-glucose-tolerant BGL genes exhibited higher sensitivity to regulation than the glucose-tolerant BGL genes, which was suppressed during the composting process. Compared with the expression of endoglucanase and exoglucanase, the functional microbial communities exhibited a different transcriptional regulation of BGL genes during the cooling phase of natural composting. BGL-producing microbial communities upregulated the expression of glucose-tolerant BGL under carbon catabolite repression due to the increased glucose concentration, whereas the expression of non-glucose-tolerant BGL was suppressed. CONCLUSION Our results support the hypothesis that the functional microbial communities use multiple strategies of varying effectiveness to regulate the expression of BGL genes to facilitate adaptation to environmental changes.
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Affiliation(s)
- Xinyue Zhang
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Bo Ma
- School of Animal Medicine, Northeast Agricultural University, Harbin, 150030 China
- Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, 150030 China
| | - Jiawen Liu
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Xiehui Chen
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Shanshan Li
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Erlie Su
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Liyuan Gao
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Hongtao Li
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
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21
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López-Mondéjar R, Algora C, Baldrian P. Lignocellulolytic systems of soil bacteria: A vast and diverse toolbox for biotechnological conversion processes. Biotechnol Adv 2019; 37:107374. [DOI: 10.1016/j.biotechadv.2019.03.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/06/2019] [Accepted: 03/21/2019] [Indexed: 12/12/2022]
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22
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Adair KL, Lindgreen S, Poole AM, Young LM, Bernard-Verdier M, Wardle DA, Tylianakis JM. Above and belowground community strategies respond to different global change drivers. Sci Rep 2019; 9:2540. [PMID: 30796259 PMCID: PMC6385336 DOI: 10.1038/s41598-019-39033-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 01/11/2019] [Indexed: 02/01/2023] Open
Abstract
Environmental changes alter the diversity and structure of communities. By shifting the range of species traits that will be successful under new conditions, environmental drivers can also dramatically impact ecosystem functioning and resilience. Above and belowground communities jointly regulate whole-ecosystem processes and responses to change, yet they are frequently studied separately. To determine whether these communities respond similarly to environmental changes, we measured taxonomic and trait-based responses of plant and soil microbial communities to four years of experimental warming and nitrogen deposition in a temperate grassland. Plant diversity responded strongly to N addition, whereas soil microbial communities responded primarily to warming, likely via an associated decrease in soil moisture. These above and belowground changes were associated with selection for more resource-conservative plant and microbe growth strategies, which reduced community functional diversity. Functional characteristics of plant and soil microbial communities were weakly correlated (P = 0.07) under control conditions, but not when above or belowground communities were altered by either global change driver. These results highlight the potential for global change drivers operating simultaneously to have asynchronous impacts on above and belowground components of ecosystems. Assessment of a single ecosystem component may therefore greatly underestimate the whole-system impact of global environmental changes.
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Affiliation(s)
- Karen L Adair
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand. .,Department of Entomology, Comstock Hall, Cornell University, Ithaca, 14853, NY, USA.
| | - Stinus Lindgreen
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand.,H. Lundbeck A/S, Ottiliavej 9, 2500, Valby, Denmark
| | - Anthony M Poole
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand.,School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Laura M Young
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - Maud Bernard-Verdier
- Bio-Protection Research Centre, Lincoln University, PO Box 85084, Lincoln, 7647, Canterbury, New Zealand.,Freie Universität Berlin, Institut für Biologie, Königin-Luise-Str. 1-3, 14195, Berlin-Dahlem, Germany
| | - David A Wardle
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE901-83, Umea, Sweden.,Asian School of the Environment, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Jason M Tylianakis
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand. .,Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, United Kingdom.
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Treseder KK, Berlemont R, Allison SD, Martiny AC. Drought increases the frequencies of fungal functional genes related to carbon and nitrogen acquisition. PLoS One 2018; 13:e0206441. [PMID: 30462680 PMCID: PMC6248904 DOI: 10.1371/journal.pone.0206441] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/14/2018] [Indexed: 12/16/2022] Open
Abstract
Although water is a critical resource for organisms, microbially-mediated processes such as decomposition and nitrogen (N) transformations can endure within ecosystems even when water is scarce. To identify underlying mechanisms, we examined the genetic potential for fungi to contribute to specific aspects of carbon (C) and N cycling in a drought manipulation in Southern California grassland. In particular, we measured the frequency of fungal functional genes encoding enzymes that break down cellulose and chitin, and take up ammonium and amino acids, in decomposing litter. Furthermore, we used "microbial cages" to reciprocally transplant litter and microbes between control and drought plots. This approach allowed us to distinguish direct effects of drought in the plot environment versus indirect effects via shifts in the microbial community or changes in litter chemistry. For every fungal functional gene we examined, the frequency of that gene within the microbial community increased significantly in drought plots compared to control plots. In contrast, when plot environment was held constant, frequencies of these fungal functional genes did not differ significantly between control-derived microbes versus drought-derived microbes, or between control-derived litter versus drought-derived litter. It appears that drought directly selects for fungi with the genetic capacity to acquire these specific C- and N-containing compounds. This genetic trait may allow fungi to take advantage of ephemeral water supplies. Altogether, proliferation of fungi with the genetic capacity for C and N acquisition may contribute to the maintenance of biogeochemical cycling under drought.
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Affiliation(s)
- Kathleen K. Treseder
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, United States of America
| | - Renaud Berlemont
- Department of Biological Sciences, California State University Long Beach, Long Beach, California, United States of America
| | - Steven D. Allison
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, United States of America
- Department of Earth System Science, University of California Irvine, Irvine, California, United States of America
| | - Adam C. Martiny
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, United States of America
- Department of Earth System Science, University of California Irvine, Irvine, California, United States of America
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24
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Decomposition responses to climate depend on microbial community composition. Proc Natl Acad Sci U S A 2018; 115:11994-11999. [PMID: 30397146 DOI: 10.1073/pnas.1811269115] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteria and fungi drive decomposition, a fundamental process in the carbon cycle, yet the importance of microbial community composition for decomposition remains elusive. Here, we used an 18-month reciprocal transplant experiment along a climate gradient in Southern California to disentangle the effects of the microbial community versus the environment on decomposition. Specifically, we tested whether the decomposition response to climate change depends on the microbial community. We inoculated microbial decomposers from each site onto a common, irradiated leaf litter within "microbial cages" that prevent microbial exchange with the environment. We characterized fungal and bacterial composition and abundance over time and investigated the functional consequences through litter mass loss and chemistry. After 12 months, microbial communities altered both decomposition rate and litter chemistry. Further, the functional measurements depended on an interaction between the community and its climate in a manner not predicted by current theory. Moreover, microbial ecologists have traditionally considered fungi to be the primary agents of decomposition and for bacteria to play a minor role. Our results indicate that not only does climate change and transplantation have differential legacy effects among bacteria and fungi, but also that bacterial communities might be less functionally redundant than fungi with regards to decomposition. Thus, it may be time to reevaluate both the role of microbial community composition in its decomposition response to climate and the relative roles of bacterial and fungal communities in decomposition.
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25
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Peces M, Astals S, Jensen PD, Clarke WP. Deterministic mechanisms define the long-term anaerobic digestion microbiome and its functionality regardless of the initial microbial community. WATER RESEARCH 2018; 141:366-376. [PMID: 29807319 DOI: 10.1016/j.watres.2018.05.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/16/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
The impact of the starting inoculum on long-term anaerobic digestion performance, process functionality and microbial community composition remains unclear. To understand the impact of starting inoculum, active microbial communities from four different full-scale anaerobic digesters were each used to inoculate four continuous lab-scale anaerobic digesters, which were operated identically for 295 days. Digesters were operated at 15 days solid retention time, an organic loading rate of 1 g COD Lr-1 d-1 (75:25 - cellulose:casein) and 37 °C. Results showed that long-term process performance, metabolic rates (hydrolytic, acetogenic, and methanogenic) and microbial community are independent of the inoculum source. Digesters process performance converged after 80 days, while metabolic rates and microbial communities converged after 120-145 days. The convergence of the different microbial communities towards a core-community proves that the deterministic factors (process operational conditions) were a stronger driver than the initial microbial community composition. Indeed, the core-community represented 72% of the relative abundance among the four digesters. Moreover, a number of positive correlations were observed between higher metabolic rates and the relative abundance of specific microbial groups. These correlations showed that both substrate consumers and suppliers trigger higher metabolic rates, expanding the knowledge of the nexus between microorganisms and functionality. Overall, these results support that deterministic factors control microbial communities in bioreactors independently of the inoculum source. Hence, it seems plausible that a desired microbial composition and functionality can be achieved by tuning process operational conditions.
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Affiliation(s)
- M Peces
- Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, St. Lucia Campus, 4072, QLD, Australia.
| | - S Astals
- Advanced Water Management Centre, The University of Queensland, St. Lucia Campus, 4072, QLD, Australia
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, St. Lucia Campus, 4072, QLD, Australia
| | - W P Clarke
- Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, St. Lucia Campus, 4072, QLD, Australia
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Xue WL, Pan W, Lu Q, Xu QR, Wu CN, Du ST. Aquatic plant debris changes sediment enzymatic activity and microbial community structure. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:21801-21810. [PMID: 29796882 DOI: 10.1007/s11356-018-2310-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 05/13/2018] [Indexed: 06/08/2023]
Abstract
The retention of aquatic plant debris in freshwater systems favors a reduction in soluble reactive phosphorus (P) in overlying water through microbe-mediated mechanisms in sediment. For a more complete view of the changes in sediment microbial structure and functioning when receiving plant debris, the enzyme activities and microbial community structure in sediments incubated with or without plant debris were investigated. Significantly higher fluorescein diacetate (FDA) hydrolysis, alkaline phosphatase, polyphenol oxidase, cellulase, β-glucosidase, and dehydrogenase activities were observed with plant debris treatment. High-throughput pyrosequencing showed that the number of total operational taxonomic units (OTUs) of bacteria estimated by using the Chao1 analysis was 2064 (in the control) and 1821 (with the plant debris treatment). The Shannon index, functional organization, and Venn diagrams revealed that the enriched OTUs in plant debris-treated community were less diversified than those in the control sample. The prominent bacterial phyla Firmicutes and Bacteroidetes were more diverse after plant debris addition. At the class level, the relative abundance of Alphaproteobacteria increased by 114% when plant debris was added, whereas the relative abundances of Beta-, Delta-, and Gammaproteobacteria decreased by 42, 78, and 86%, respectively. Azospirillum and Dechloromonas, the dominant phylogenetic groups at the genus level, increased with plant debris addition. Our study showed the importance of the above microbial genera in plant debris-mediated P retention in sediment.
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Affiliation(s)
- Wan-Lei Xue
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Wei Pan
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Qi Lu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Qian-Ru Xu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Cai-Nan Wu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Shao-Ting Du
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China.
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Zimudzi J, van der Waals JE, Coutinho TA, Cowan DA, Valverde A. Temporal shifts of fungal communities in the rhizosphere and on tubers in potato fields. Fungal Biol 2018; 122:928-934. [PMID: 30115327 DOI: 10.1016/j.funbio.2018.05.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 05/24/2018] [Accepted: 05/29/2018] [Indexed: 10/14/2022]
Abstract
Soil fungal communities perform important ecological roles determining, at least in part, agricultural productivity. This study aimed at examining the fungal community dynamics in the potato rhizosphere across different development stages in two consecutive growing seasons (winter and summer). Microbial fingerprinting of rhizosphere soil samples collected at pre-planting, tuber initiation, flowering and at senescence was performed using ARISA in conjunction with Next Generation Sequencing (Illumina MiSeq). The epiphytic fungal communities on tubers at harvest were also investigated. Alpha-diversity was stable over time within and across the two seasons. In contrast, rhizospheric fungal community structure and composition were different between the two seasons and in the different plant growth stages within a given season, indicating the significance of the rhizosphere in shaping microbial communities. The phylum Ascomycota was dominant in the potato fungal rhizosphere, with Operational Taxonomic Units (OTUs) belonging to the genus Peyronellaea being the most abundant in all samples. Important fungal pathogens of potato, together with potential biological control agents and saprophytic species, were identified as indicator OTUs at different plant growth stages. These findings indicate that potato rhizosphere fungal communities are functionally diverse, which may contribute to soil health.
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Affiliation(s)
- Josephine Zimudzi
- Department of Plant and Soil Sciences, University of Pretoria, Pretoria, South Africa
| | | | - Teresa A Coutinho
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | - Don A Cowan
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | - Angel Valverde
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa; Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
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Yang Y, Dou Y, An S. Testing association between soil bacterial diversity and soil carbon storage on the Loess Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 626:48-58. [PMID: 29335174 DOI: 10.1016/j.scitotenv.2018.01.081] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 12/20/2017] [Accepted: 01/09/2018] [Indexed: 06/07/2023]
Abstract
Bacteria are widely distributed and play an important role in soil carbon (C) cycling. The impact of soil bacterial diversity on soil C storage has been well established, yet little is known about the underlying mechanisms and the interactions among them. Here, we examined the association between soil bacterial diversity and soil C storage in relation to vegetation restoration on the Loess Plateau. The dominant phyla among land use types (artificial forest, Af; natural shrubland, Ns; artificial grassland, Ag; natural grassland, Ng; slope cropland, Sc) were Acidobacteria, Actinobacteria, Alphaproteobacteria, and Betaproteobacteria, which transited from Acidobacteria-dominant to Actinobacteria-dominant community due to vegetation restoration. Soil C storage and the Shannon diversity index of soil bacterial community (HBacteria) showed the order Ns > Ng > Af > Ag > Sc, whereas no significant difference was found in Good's coverage (p > .05). Further, a strong relationship was observed between the relative abundance of dominant bacterial groups and soil C storage (p < .05). Additionally, soil bacterial diversity was closely related to soil C storage based on the structural equation model (SEM) and generalized additive models (GAMs). Specifically, soil C storage had the largest deterministic effects, explaining >70% of the variation and suggesting a strong association between soil C storage and soil bacterial diversity. Overall, we propose that further studies are necessary with a focus on the soil bacterial groups with specific functions in relation to soil C storage on the Loess Plateau.
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Affiliation(s)
- Yang Yang
- College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China
| | - Yanxing Dou
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China
| | - Shaoshan An
- College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China.
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29
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Liu J, Li C, Jing J, Zhao P, Luo Z, Cao M, Ma Z, Jia T, Chai B. Ecological patterns and adaptability of bacterial communities in alkaline copper mine drainage. WATER RESEARCH 2018; 133:99-109. [PMID: 29367051 DOI: 10.1016/j.watres.2018.01.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/31/2017] [Accepted: 01/05/2018] [Indexed: 06/07/2023]
Abstract
Environmental gradient have strong effects on community assembly processes. In order to reveal the effects of alkaline mine drainage (AlkMD) on bacterial and denitrifying bacterial community compositions and diversity in tailings reservoir, here we conducted an experiment to examine all and core bacterial taxa and denitrifying functional genes's (nirS, nirK, nosZΙ) abundance along a chemical gradient in tailings water in Shibahe copper tailings in Zhongtiaoshan, China. Differences in bacterial and denitrifying bacterial community compositions in different habitats and their relationships with environmental parameters were analyzed. The results showed that the richness and diversity of bacterial community in downstream seeping water (SDSW) were the largest, while that in upstream tailings water (STW1) were the lowest. The diversity and abundance of bacterial communities tended to increase from STW1 to SDSW. The variation of bacterial community diversity was significantly related to electroconductibility (EC), nitrate (NO3-), nitrite (NO2-), total carbon (TC), inorganic carbon (IC) and sulfate (SO42-), but was not correlated with geographic distance in local scale. Core taxa from class to genus were all significantly related to NO3- and NO2-. Core taxa Rhodobacteraceae, Rhodobacter, Acinetobacter and Hydrogenophaga were typical denitrifying bacteria. The variation trends of these groups were consistent with the copy number of nirS, nirK and nosZΙ, demonstrating their importance in the process of nitrogen reduction. The copy number of nirK, nosZΙ and nirS/16S rDNA, nirK/16Sr DNA correlated strongly with NO3-, NO2- and IC, but nirS and nosZI/16SrDNA had no significant correlation with NO3- and NO2-. The copy numbers of denitrifying functional genes (nirS, nirK and nosZΙ) were negatively correlated with heavy metal plumbum (Pb) and zinc (Zn). It showed that heavy metal contamination was an important factor affecting the structure of denitrifying bacterial community in AlkMD. In this study we have identified the distribution pattern of bacterial community along physiochemical gradients in alkaline tailings reservoir and displayed the driving force of shaping the structure of bacterial community. The influence of NO3-, NO2-, IC and heavy metal Pb and Zn on bacterial community might via their influence on the functional groups involving nitrogen, carbon and metal metabolisms.
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Affiliation(s)
- Jinxian Liu
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Cui Li
- Faculty of Environment Economics, Shanxi University of Finance and Economics, Taiyuan, 030006, China
| | - Juhui Jing
- Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Pengyu Zhao
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Zhengming Luo
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Miaowen Cao
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Zhuanzhuan Ma
- Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Tong Jia
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Baofeng Chai
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China.
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Sanyal A, Antony R, Samui G, Thamban M. Microbial communities and their potential for degradation of dissolved organic carbon in cryoconite hole environments of Himalaya and Antarctica. Microbiol Res 2018; 208:32-42. [PMID: 29551210 DOI: 10.1016/j.micres.2018.01.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/04/2018] [Accepted: 01/13/2018] [Indexed: 02/03/2023]
Abstract
Cryoconite holes (cylindrical melt-holes on the glacier surface) are important hydrological and biological systems within glacial environments that support diverse microbial communities and biogeochemical processes. This study describes retrievable heterotrophic microbes in cryoconite hole water from three geographically distinct sites in Antarctica, and a Himalayan glacier, along with their potential to degrade organic compounds found in these environments. Microcosm experiments (22 days) show that 13-60% of the dissolved organic carbon in the water within cryoconite holes is bio-available to resident microbes. Biodegradation tests of organic compounds such as lactate, acetate, formate, propionate and oxalate that are present in cryoconite hole water show that microbes have good potential to metabolize the compounds tested. Substrate utilization tests on Biolog Ecoplate show that microbial communities in the Himalayan samples are able to oxidize a diverse array of organic substrates including carbohydrates, carboxylic acids, amino acids, amines/amides and polymers, while Antarctic communities generally utilized complex polymers. In addition, as determined by the extracellular enzyme activities, majority of the microbes (82%, total of 355) isolated in this study (Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria and Basidiomycota) had ability to degrade a variety of compounds such as proteins, lipids, carbohydrates, cellulose and lignin that are documented to be present within cryoconite holes. Thus, microbial communities have good potential to metabolize organic compounds found in the cryoconite hole environment, thereby influencing the water chemistry in these holes. Moreover, microbes exported downstream during melting and flushing of cryoconite holes may participate in carbon cycling processes in recipient ecosystems.
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Affiliation(s)
- Aritri Sanyal
- ESSO-National centre for Antarctic and Ocean Research, Headland Sada, Vasco-Da-Gama, Goa 403804, India
| | - Runa Antony
- ESSO-National centre for Antarctic and Ocean Research, Headland Sada, Vasco-Da-Gama, Goa 403804, India.
| | - Gautami Samui
- ESSO-National centre for Antarctic and Ocean Research, Headland Sada, Vasco-Da-Gama, Goa 403804, India
| | - Meloth Thamban
- ESSO-National centre for Antarctic and Ocean Research, Headland Sada, Vasco-Da-Gama, Goa 403804, India
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Nguyen STC, Freund HL, Kasanjian J, Berlemont R. Function, distribution, and annotation of characterized cellulases, xylanases, and chitinases from CAZy. Appl Microbiol Biotechnol 2018; 102:1629-1637. [PMID: 29359269 DOI: 10.1007/s00253-018-8778-y] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 01/06/2018] [Accepted: 01/09/2018] [Indexed: 11/30/2022]
Abstract
The enzymatic deconstruction of structural polysaccharides, which relies on the production of specific glycoside hydrolases (GHs), is an essential process across environments. Over the past few decades, researchers studying the diversity and evolution of these enzymes have isolated and biochemically characterized thousands of these proteins. The carbohydrate-active enzymes database (CAZy) lists these proteins and provides some metadata. Here, the sequences and metadata of characterized sequences derived from GH families associated with the deconstruction of cellulose, xylan, and chitin were collected and discussed. First, although few polyspecific enzymes are identified, characterized GH families are mostly monospecific. Next, the taxonomic distribution of characterized GH mirrors the distribution of identified sequences in sequenced genomes. This provides a rationale for connecting the identification of GH sequences to specific reactions or lineages. Finally, we tested the annotation of the characterized GHs using HMM scan and the protein families database (Pfam). The vast majority of GHs targeting cellulose, xylan, and chitin can be identified using this publicly accessible approach.
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Affiliation(s)
- Stanley T C Nguyen
- Department of Biological Sciences, California State University-Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840-9502, USA
| | - Hannah L Freund
- Department of Biological Sciences, California State University-Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840-9502, USA
| | - Joshua Kasanjian
- Department of Biological Sciences, California State University-Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840-9502, USA
| | - Renaud Berlemont
- Department of Biological Sciences, California State University-Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840-9502, USA.
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32
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Hartman WH, Ye R, Horwath WR, Tringe SG. A genomic perspective on stoichiometric regulation of soil carbon cycling. THE ISME JOURNAL 2017; 11:2652-2665. [PMID: 28731470 PMCID: PMC5702722 DOI: 10.1038/ismej.2017.115] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 02/01/2023]
Abstract
Similar to plant growth, soil carbon (C) cycling is constrained by the availability of nitrogen (N) and phosphorus (P). We hypothesized that stoichiometric control over soil microbial C cycling may be shaped by functional guilds with distinct nutrient substrate preferences. Across a series of rice fields spanning 5-25% soil C (N:P from 1:12 to 1:70), C turnover was best correlated with P availability and increased with experimental N addition only in lower C (mineral) soils with N:P⩽16. Microbial community membership also varied with soil stoichiometry but not with N addition. Shotgun metagenome data revealed changes in community functions with increasing C turnover, including a shift from aromatic C to carbohydrate utilization accompanied by lower N uptake and P scavenging. Similar patterns of C, N and P acquisition, along with higher ribosomal RNA operon copy numbers, distinguished that microbial taxa positively correlated with C turnover. Considering such tradeoffs in genomic resource allocation patterns among taxa strengthened correlations between microbial community composition and C cycling, suggesting simplified guilds amenable to ecosystem modeling. Our results suggest that patterns of soil C turnover may reflect community-dependent metabolic shifts driven by resource allocation strategies, analogous to growth rate-stoichiometry coupling in animal and plant communities.
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Affiliation(s)
- Wyatt H Hartman
- Department of Energy, Joint Genome Institute, Walnut Creek CA, USA
| | - Rongzhong Ye
- Department of Land, Air and Water Resources, University of California, Davis CA, USA
- Plant and Environmental Sciences Department, Clemson University, Clemson SC, USA
| | - William R Horwath
- Department of Land, Air and Water Resources, University of California, Davis CA, USA
| | - Susannah G Tringe
- Department of Energy, Joint Genome Institute, Walnut Creek CA, USA
- School of Natural Sciences, University of California, Merced CA, USA
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Microdiversity of an Abundant Terrestrial Bacterium Encompasses Extensive Variation in Ecologically Relevant Traits. mBio 2017; 8:mBio.01809-17. [PMID: 29138307 PMCID: PMC5686540 DOI: 10.1128/mbio.01809-17] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Much genetic diversity within a bacterial community is likely obscured by microdiversity within operational taxonomic units (OTUs) defined by 16S rRNA gene sequences. However, it is unclear how variation within this microdiversity influences ecologically relevant traits. Here, we employ a multifaceted approach to investigate microdiversity within the dominant leaf litter bacterium, Curtobacterium, which comprises 7.8% of the bacterial community at a grassland site undergoing global change manipulations. We use cultured bacterial isolates to interpret metagenomic data, collected in situ over 2 years, together with lab-based physiological assays to determine the extent of trait variation within this abundant OTU. The response of Curtobacterium to seasonal variability and the global change manipulations, specifically an increase in relative abundance under decreased water availability, appeared to be conserved across six Curtobacterium lineages identified at this site. Genomic and physiological analyses in the lab revealed that degradation of abundant polymeric carbohydrates within leaf litter, cellulose and xylan, is nearly universal across the genus, which may contribute to its high abundance in grassland leaf litter. However, the degree of carbohydrate utilization and temperature preference for this degradation varied greatly among clades. Overall, we find that traits within Curtobacterium are conserved at different phylogenetic depths. We speculate that similar to bacteria in marine systems, diverse microbes within this taxon may be structured in distinct ecotypes that are key to understanding Curtobacterium abundance and distribution in the environment. Despite the plummeting costs of sequencing, characterizing the fine-scale genetic diversity of a microbial community—and interpreting its functional importance—remains a challenge. Indeed, most studies, particularly studies of soil, assess community composition at a broad genetic level by classifying diversity into taxa (OTUs) defined by 16S rRNA sequence similarity. However, these classifications potentially obscure variation in traits that result in fine-scale ecological differentiation among closely related strains. Here, we investigated “microdiversity” in a highly diverse and poorly characterized soil system (leaf litter in a southern Californian grassland). We focused on the most abundant bacterium, Curtobacterium, which by standard methods is grouped into only one OTU. We find that the degree of carbohydrate usage and temperature preference vary within the OTU, whereas its responses to changes in precipitation are relatively uniform. These results suggest that microdiversity may be key to understanding how soil bacterial diversity is linked to ecosystem functioning.
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Maltz MR, Treseder KK, McGuire KL. Links between plant and fungal diversity in habitat fragments of coastal shrubland. PLoS One 2017; 12:e0184991. [PMID: 28926606 PMCID: PMC5604993 DOI: 10.1371/journal.pone.0184991] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 09/04/2017] [Indexed: 12/03/2022] Open
Abstract
Habitat fragmentation is widespread across ecosystems, detrimentally affecting biodiversity. Although most habitat fragmentation studies have been conducted on macroscopic organisms, microbial communities and fungal processes may also be threatened by fragmentation. This study investigated whether fragmentation, and the effects of fragmentation on plants, altered fungal diversity and function within a fragmented shrubland in southern California. Using fluorimetric techniques, we assayed enzymes from plant litter collected from fragments of varying sizes to investigate enzymatic responses to fragmentation. To isolate the effects of plant richness from those of fragment size on fungi, we deployed litter bags containing different levels of plant litter diversity into the largest fragment and incubated in the field for one year. Following field incubation, we determined litter mass loss and conducted molecular analyses of fungal communities. We found that leaf-litter enzyme activity declined in smaller habitat fragments with less diverse vegetation. Moreover, we detected greater litter mass loss in litter bags containing more diverse plant litter. Additionally, bags with greater plant litter diversity harbored greater numbers of fungal taxa. These findings suggest that both plant litter resources and fungal function may be affected by habitat fragmentation’s constraints on plants, possibly because plant species differ chemically, and may thus decompose at different rates. Diverse plant assemblages may produce a greater variety of litter resources and provide more ecological niche space, which may support greater numbers of fungal taxa. Thus, reduced plant diversity may constrain both fungal taxa richness and decomposition in fragmented coastal shrublands. Altogether, our findings provide evidence that even fungi may be affected by human-driven habitat fragmentation via direct effects of fragmentation on plants. Our findings underscore the importance of restoring diverse vegetation communities within larger coastal sage scrub fragments and suggest that this may be an effective way to improve the functional capacity of degraded sites.
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Affiliation(s)
- Mia R. Maltz
- Center for Conservation Biology, University of California Riverside, Riverside, California, United States of America
- * E-mail:
| | - Kathleen K. Treseder
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, United States of America
| | - Krista L. McGuire
- Department of Biology, University of Oregon, Eugene, Oregon, United States of America
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35
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Lewin GR, Carlos C, Chevrette MG, Horn HA, McDonald BR, Stankey RJ, Fox BG, Currie CR. Evolution and Ecology of Actinobacteria and Their Bioenergy Applications. Annu Rev Microbiol 2017; 70:235-54. [PMID: 27607553 DOI: 10.1146/annurev-micro-102215-095748] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ancient phylum Actinobacteria is composed of phylogenetically and physiologically diverse bacteria that help Earth's ecosystems function. As free-living organisms and symbionts of herbivorous animals, Actinobacteria contribute to the global carbon cycle through the breakdown of plant biomass. In addition, they mediate community dynamics as producers of small molecules with diverse biological activities. Together, the evolution of high cellulolytic ability and diverse chemistry, shaped by their ecological roles in nature, make Actinobacteria a promising group for the bioenergy industry. Specifically, their enzymes can contribute to industrial-scale breakdown of cellulosic plant biomass into simple sugars that can then be converted into biofuels. Furthermore, harnessing their ability to biosynthesize a range of small molecules has potential for the production of specialty biofuels.
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Affiliation(s)
- Gina R Lewin
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Camila Carlos
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Marc G Chevrette
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Heidi A Horn
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706;
| | - Bradon R McDonald
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Robert J Stankey
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Brian G Fox
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726.,Department of Biochemistry, University of Wisconsin-Madison, Wisconsin 53706
| | - Cameron R Currie
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
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Polysaccharide Degradation Capability of Actinomycetales Soil Isolates from a Semiarid Grassland of the Colorado Plateau. Appl Environ Microbiol 2017; 83:AEM.03020-16. [PMID: 28087533 DOI: 10.1128/aem.03020-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/10/2017] [Indexed: 02/03/2023] Open
Abstract
Among the bacteria, members of the order Actinomycetales are considered quintessential degraders of complex polysaccharides in soils. However, studies examining complex polysaccharide degradation by Actinomycetales (other than Streptomyces spp.) in soils are limited. Here, we examine the lignocellulolytic and chitinolytic potential of 112 Actinomycetales strains, encompassing 13 families, isolated from a semiarid grassland of the Colorado Plateau in Utah. Members of the Streptomycetaceae, Pseudonocardiaceae, Micromonosporaceae, and Promicromonosporaceae families exhibited robust activity against carboxymethyl cellulose, xylan, chitin, and pectin substrates (except for low/no pectinase activity by the Micromonosporaceae). When incubated in a hydrated mixture of blended Stipa and Hilaria grass biomass over a 5-week period, Streptomyces and Saccharothrix (a member of the Pseudonocardiaceae) isolates produced high levels of extracellular enzyme activity, such as endo- and exocellulase, glucosidase, endo- and exoxylosidase, and arabinofuranosidase. These characteristics make them well suited to degrade the cellulose and hemicellulose components of grass cell walls. On the basis of the polysaccharide degradation profiles of the isolates, relative abundance of Actinomycetales sequences in 16S rRNA gene surveys of Colorado Plateau soils, and analysis of genes coding for polysaccharide-degrading enzymes among 237 Actinomycetales genomes in the CAZy database and 5 genomes from our isolates, we posit that Streptomyces spp. and select members of the Pseudonocardiaceae and Micromonosporaceae likely play an important role in the degradation of hemicellulose, cellulose, and chitin substances in dryland soils.IMPORTANCE Shifts in the relative abundance of Actinomycetales taxa have been observed in soil microbial community surveys during large, manipulated climate change field studies. However, our limited understanding of the ecophysiology of diverse Actinomycetales taxa in soil systems undermines attempts to determine the underlying causes of the population shifts or their impact on carbon cycling in soil. This study combines a systematic analysis of the polysaccharide degradation potential of a diverse collection of Actinomycetales isolates from surface soils of a semiarid grassland with analysis of genomes from five of these isolates and publicly available Actinomycetales genomes for genes encoding polysaccharide-active enzymes. The results address an important gap in knowledge of Actinomycetales ecophysiology-identification of key taxa capable of facilitating lignocellulose degradation in dryland soils. Information from this study will benefit future metagenomic studies related to carbon cycling in dryland soils by providing a baseline linkage of Actinomycetales phylogeny with lignocellulolytic functional potential.
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Martiny JBH, Martiny AC, Weihe C, Lu Y, Berlemont R, Brodie EL, Goulden ML, Treseder KK, Allison SD. Microbial legacies alter decomposition in response to simulated global change. THE ISME JOURNAL 2017; 11:490-499. [PMID: 27740610 PMCID: PMC5270563 DOI: 10.1038/ismej.2016.122] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/11/2016] [Accepted: 08/05/2016] [Indexed: 01/19/2023]
Abstract
Terrestrial ecosystem models assume that microbial communities respond instantaneously, or are immediately resilient, to environmental change. Here we tested this assumption by quantifying the resilience of a leaf litter community to changes in precipitation or nitrogen availability. By manipulating composition within a global change experiment, we decoupled the legacies of abiotic parameters versus that of the microbial community itself. After one rainy season, more variation in fungal composition could be explained by the original microbial inoculum than the litterbag environment (18% versus 5.5% of total variation). This compositional legacy persisted for 3 years, when 6% of the variability in fungal composition was still explained by the microbial origin. In contrast, bacterial composition was generally more resilient than fungal composition. Microbial functioning (measured as decomposition rate) was not immediately resilient to the global change manipulations; decomposition depended on both the contemporary environment and rainfall the year prior. Finally, using metagenomic sequencing, we showed that changes in precipitation, but not nitrogen availability, altered the potential for bacterial carbohydrate degradation, suggesting why the functional consequences of the two experiments may have differed. Predictions of how terrestrial ecosystem processes respond to environmental change may thus be improved by considering the legacies of microbial communities.
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Affiliation(s)
- Jennifer BH Martiny
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
| | - Adam C Martiny
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
- Department of Earth System Science, University of California, Irvine, CA, USA
| | - Claudia Weihe
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
| | - Ying Lu
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
| | - Renaud Berlemont
- Department of Earth System Science, University of California, Irvine, CA, USA
- Department of Biology, California State University, Long Beach, CA, USA
| | - Eoin L Brodie
- Ecology Department, Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Michael L Goulden
- Department of Earth System Science, University of California, Irvine, CA, USA
| | - Kathleen K Treseder
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
| | - Steven D Allison
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
- Department of Earth System Science, University of California, Irvine, CA, USA
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Mello BL, Alessi AM, Riaño-Pachón DM, deAzevedo ER, Guimarães FEG, Espirito Santo MC, McQueen-Mason S, Bruce NC, Polikarpov I. Targeted metatranscriptomics of compost-derived consortia reveals a GH11 exerting an unusual exo-1,4-β-xylanase activity. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:254. [PMID: 29118851 PMCID: PMC5667448 DOI: 10.1186/s13068-017-0944-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/24/2017] [Indexed: 05/09/2023]
Abstract
BACKGROUND Using globally abundant crop residues as a carbon source for energy generation and renewable chemicals production stand out as a promising solution to reduce current dependency on fossil fuels. In nature, such as in compost habitats, microbial communities efficiently degrade the available plant biomass using a diverse set of synergistic enzymes. However, deconstruction of lignocellulose remains a challenge for industry due to recalcitrant nature of the substrate and the inefficiency of the enzyme systems available, making the economic production of lignocellulosic biofuels difficult. Metatranscriptomic studies of microbial communities can unveil the metabolic functions employed by lignocellulolytic consortia and identify novel biocatalysts that could improve industrial lignocellulose conversion. RESULTS In this study, a microbial community from compost was grown in minimal medium with sugarcane bagasse sugarcane bagasse as the sole carbon source. Solid-state nuclear magnetic resonance was used to monitor lignocellulose degradation; analysis of metatranscriptomic data led to the selection and functional characterization of several target genes, revealing the first glycoside hydrolase from Carbohydrate Active Enzyme family 11 with exo-1,4-β-xylanase activity. The xylanase crystal structure was resolved at 1.76 Å revealing the structural basis of exo-xylanase activity. Supplementation of a commercial cellulolytic enzyme cocktail with the xylanase showed improvement in Avicel hydrolysis in the presence of inhibitory xylooligomers. CONCLUSIONS This study demonstrated that composting microbiomes continue to be an excellent source of biotechnologically important enzymes by unveiling the diversity of enzymes involved in in situ lignocellulose degradation.
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Affiliation(s)
- Bruno L. Mello
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense 400, São Carlos, SP 13560-970 Brazil
| | - Anna M. Alessi
- Department of Biology, University of York, Wentworth Way, York, YO10 5DD UK
| | - Diego M. Riaño-Pachón
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol, Centro Nacional de Pesquisa em Energia e Materiais, Rua Giuseppe Máximo Scalfaro 10000, Campinas, SP 13083-100 Brazil
- Laboratório de Biologia de Sistemas Regulatórios, Departamento de Química, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP 05508-000 Brazil
| | - Eduardo R. deAzevedo
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense 400, São Carlos, SP 13560-970 Brazil
| | - Francisco E. G. Guimarães
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense 400, São Carlos, SP 13560-970 Brazil
| | - Melissa C. Espirito Santo
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense 400, São Carlos, SP 13560-970 Brazil
| | | | - Neil C. Bruce
- Department of Biology, University of York, Wentworth Way, York, YO10 5DD UK
| | - Igor Polikarpov
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense 400, São Carlos, SP 13560-970 Brazil
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Berlemont R, Martiny AC. Glycoside Hydrolases across Environmental Microbial Communities. PLoS Comput Biol 2016; 12:e1005300. [PMID: 27992426 PMCID: PMC5218504 DOI: 10.1371/journal.pcbi.1005300] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 01/06/2017] [Accepted: 12/11/2016] [Indexed: 11/25/2022] Open
Abstract
Across many environments microbial glycoside hydrolases support the enzymatic processing of carbohydrates, a critical function in many ecosystems. Little is known about how the microbial composition of a community and the potential for carbohydrate processing relate to each other. Here, using 1,934 metagenomic datasets, we linked changes in community composition to variation of potential for carbohydrate processing across environments. We were able to show that each ecosystem-type displays a specific potential for carbohydrate utilization. Most of this potential was associated with just 77 bacterial genera. The GH content in bacterial genera is best described by their taxonomic affiliation. Across metagenomes, fluctuations of the microbial community structure and GH potential for carbohydrate utilization were correlated. Our analysis reveals that both deterministic and stochastic processes contribute to the assembly of complex microbial communities.
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Affiliation(s)
- Renaud Berlemont
- Dept. of Biological Sciences, California State University, Long Beach, California, United States of America
| | - Adam C. Martiny
- Dept. of Earth System Science, University of California, Irvine, California, United States of America
- Dept. of Ecology and Evolutionary Biology, University of California, Irvine, California, United States of America
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Chase AB, Arevalo P, Polz MF, Berlemont R, Martiny JBH. Evidence for Ecological Flexibility in the Cosmopolitan Genus Curtobacterium. Front Microbiol 2016; 7:1874. [PMID: 27920771 PMCID: PMC5118839 DOI: 10.3389/fmicb.2016.01874] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/07/2016] [Indexed: 12/30/2022] Open
Abstract
Assigning ecological roles to bacterial taxa remains imperative to understanding how microbial communities will respond to changing environmental conditions. Here we analyze the genus Curtobacterium, as it was found to be the most abundant taxon in a leaf litter community in southern California. Traditional characterization of this taxon predominantly associates it as the causal pathogen in the agricultural crops of dry beans. Therefore, we sought to investigate whether the abundance of this genus was because of its role as a plant pathogen or another ecological role. By collating >24,000 16S rRNA sequences with 120 genomes across the Microbacteriaceae family, we show that Curtobacterium has a global distribution with a predominant presence in soil ecosystems. Moreover, this genus harbors a high diversity of genomic potential for the degradation of carbohydrates, specifically with regards to structural polysaccharides. We conclude that Curtobacterium may be responsible for the degradation of organic matter within litter communities.
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Affiliation(s)
- Alexander B. Chase
- Department of Ecology and Evolutionary Biology, University of California, IrvineIrvine, CA, USA
| | - Philip Arevalo
- Parsons Laboratory for Environmental Science and Engineering, Massachusetts Institute of TechnologyCambridge, MA, USA
| | - Martin F. Polz
- Parsons Laboratory for Environmental Science and Engineering, Massachusetts Institute of TechnologyCambridge, MA, USA
| | - Renaud Berlemont
- Department of Biological Sciences, California State University Long BeachLong Beach, CA, USA
| | - Jennifer B. H. Martiny
- Department of Ecology and Evolutionary Biology, University of California, IrvineIrvine, CA, USA
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Cellulose and hemicellulose decomposition by forest soil bacteria proceeds by the action of structurally variable enzymatic systems. Sci Rep 2016; 6:25279. [PMID: 27125755 PMCID: PMC4850484 DOI: 10.1038/srep25279] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/14/2016] [Indexed: 12/22/2022] Open
Abstract
Evidence shows that bacteria contribute actively to the decomposition of cellulose and hemicellulose in forest soil; however, their role in this process is still unclear. Here we performed the screening and identification of bacteria showing potential cellulolytic activity from litter and organic soil of a temperate oak forest. The genomes of three cellulolytic isolates previously described as abundant in this ecosystem were sequenced and their proteomes were characterized during the growth on plant biomass and on microcrystalline cellulose. Pedobacter and Mucilaginibacter showed complex enzymatic systems containing highly diverse carbohydrate-active enzymes for the degradation of cellulose and hemicellulose, which were functionally redundant for endoglucanases, β-glucosidases, endoxylanases, β-xylosidases, mannosidases and carbohydrate-binding modules. Luteibacter did not express any glycosyl hydrolases traditionally recognized as cellulases. Instead, cellulose decomposition was likely performed by an expressed GH23 family protein containing a cellulose-binding domain. Interestingly, the presence of plant lignocellulose as well as crystalline cellulose both trigger the production of a wide set of hydrolytic proteins including cellulases, hemicellulases and other glycosyl hydrolases. Our findings highlight the extensive and unexplored structural diversity of enzymatic systems in cellulolytic soil bacteria and indicate the roles of multiple abundant bacterial taxa in the decomposition of cellulose and other plant polysaccharides.
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Abstract
Glycoside hydrolases are important enzymes that support bacterial growth by enabling the degradation of polysaccharides (e.g., starch, cellulose, xylan, and chitin) in the environment. Presently, little is known about the overall phylogenetic distribution of the genomic potential to degrade these polysaccharides in bacteria. However, knowing the phylogenetic breadth of these traits may help us predict the overall polysaccharide processing in environmental microbial communities. In order to address this, we identified and analyzed the distribution of 392,166 enzyme genes derived from 53 glycoside hydrolase families in 8,133 sequenced bacterial genomes. Enzymes for oligosaccharides and starch/glycogen were observed in most taxonomic groups, whereas glycoside hydrolases for structural polymers (i.e., cellulose, xylan, and chitin) were observed in clusters of relatives at taxonomic levels ranging from species to genus as determined by consenTRAIT. The potential for starch and glycogen processing, as well as oligosaccharide processing, was observed in 85% of the strains, whereas 65% possessed enzymes to degrade some structural polysaccharides (i.e., cellulose, xylan, or chitin). Potential degraders targeting one, two, and three structural polysaccharides accounted for 22.6, 32.9, and 9.3% of genomes analyzed, respectively. Finally, potential degraders targeting multiple structural polysaccharides displayed increased potential for oligosaccharide deconstruction. This study provides a framework for linking the potential for polymer deconstruction with phylogeny in complex microbial assemblages.
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Talamantes D, Biabini N, Dang H, Abdoun K, Berlemont R. Natural diversity of cellulases, xylanases, and chitinases in bacteria. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:133. [PMID: 27366206 PMCID: PMC4928363 DOI: 10.1186/s13068-016-0538-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 05/31/2016] [Indexed: 05/16/2023]
Abstract
BACKGROUND Glycoside hydrolases (GH) targeting cellulose, xylan, and chitin are common in the bacterial genomes that have been sequenced. Little is known, however, about the architecture of multi-domain and multi-activity glycoside hydrolases. In these enzymes, combined catalytic domains act synergistically and thus display overall improved catalytic efficiency, making these proteins of high interest for the biofuel technology industry. RESULTS Here, we identify the domain organization in 40,946 proteins targeting cellulose, xylan, and chitin derived from 11,953 sequenced bacterial genomes. These bacteria are known to be capable, or to have the potential, to degrade polysaccharides, or are newly identified potential degraders (e.g., Actinospica, Hamadaea, Cystobacter, and Microbispora). Most of the proteins we identified contain a single catalytic domain that is frequently associated with an accessory non-catalytic domain. Regarding multi-domain proteins, we found that many bacterial strains have unique GH protein architectures and that the overall protein organization is not conserved across most genera. We identified 217 multi-activity proteins with at least two GH domains for cellulose, xylan, and chitin. Of these proteins, 211 have GH domains targeting similar or associated substrates (i.e., cellulose and xylan), whereas only six proteins target both cellulose and chitin. Fifty-two percent of multi-activity GHs are hetero-GHs. Finally, GH6, -10, -44 and -48 domains were mostly C-terminal; GH9, -11, -12, and -18 were mostly N-terminal; and GH5 domains were either N- or C-terminal. CONCLUSION We identified 40,946 multi-domain/multi-activity proteins targeting cellulase, chitinase, and xylanase in bacterial genomes and proposed new candidate lineages and protein architectures for carbohydrate processing that may play a role in biofuel production.
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Affiliation(s)
- Darrian Talamantes
- Department of Biological Sciences, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, 90840-9502 USA
| | - Nazmehr Biabini
- Department of Biological Sciences, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, 90840-9502 USA
| | - Hoang Dang
- Department of Biological Sciences, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, 90840-9502 USA
| | - Kenza Abdoun
- Department of Biological Sciences, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, 90840-9502 USA
| | - Renaud Berlemont
- Department of Biological Sciences, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, 90840-9502 USA
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López-Mondéjar R, Zühlke D, Větrovský T, Becher D, Riedel K, Baldrian P. Decoding the complete arsenal for cellulose and hemicellulose deconstruction in the highly efficient cellulose decomposer Paenibacillus O199. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:104. [PMID: 27186238 PMCID: PMC4867992 DOI: 10.1186/s13068-016-0518-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/04/2016] [Indexed: 05/11/2023]
Abstract
BACKGROUND The search for new enzymes and microbial strains to degrade plant biomass is one of the most important strategies for improving the conversion processes in the production of environment-friendly chemicals and biofuels. In this study, we report a new Paenibacillus isolate, O199, which showed the highest efficiency for cellulose deconstruction in a screen of environmental isolates. Here, we provide a detailed description of the complex multi-component O199 enzymatic system involved in the degradation of lignocellulose. RESULTS We examined the genome and the proteome of O199 grown on complex lignocellulose (wheat straw) and on microcrystalline cellulose. The genome contained 476 genes with domains assigned to carbohydrate-active enzyme (CAZyme) families, including 100 genes coding for glycosyl hydrolases (GHs) putatively involved in cellulose and hemicellulose degradation. Moreover, 31 % of these CAZymes were expressed on cellulose and 29 % on wheat straw. Proteomic analyses also revealed a complex and complete set of enzymes for deconstruction of cellulose (at least 22 proteins, including 4 endocellulases, 2 exocellulases, 2 cellobiohydrolases and 2 β-glucosidases) and hemicellulose (at least 28 proteins, including 5 endoxylanases, 1 β-xylosidase, 2 xyloglucanases, 2 endomannanases, 2 licheninases and 1 endo-β-1,3(4)-glucanase). Most of these proteins were secreted extracellularly and had numerous carbohydrate-binding domains (CBMs). In addition, O199 also secreted a high number of substrate-binding proteins (SBPs), including at least 42 proteins binding carbohydrates. Interestingly, both plant lignocellulose and crystalline cellulose triggered the production of a wide array of hydrolytic proteins, including cellulases, hemicellulases, and other GHs. CONCLUSIONS Our data provide an in-depth analysis of the complex and complete set of enzymes and accessory non-catalytic proteins-GHs, CBMs, transporters, and SBPs-implicated in the high cellulolytic capacity shown by this bacterial strain. The large diversity of hydrolytic enzymes and the extracellular secretion of most of them supports the use of Paenibacillus O199 as a candidate for second-generation technologies using paper or lignocellulosic agricultural wastes.
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Affiliation(s)
- Rubén López-Mondéjar
- />Laboratory of Environmental Microbiology, Institute of Microbiology of the CAS, v. v. i., Průmyslová 595, 252 42 Vestec, Czech Republic
| | - Daniela Zühlke
- />Institute of Microbiology, Ernst-Moritz-Arndt-University of Greifswald, Friedrich-Ludwig-Jahnstrasse 15, 17487 Greifswald, Germany
| | - Tomáš Větrovský
- />Laboratory of Environmental Microbiology, Institute of Microbiology of the CAS, v. v. i., Průmyslová 595, 252 42 Vestec, Czech Republic
| | - Dörte Becher
- />Institute of Microbiology, Ernst-Moritz-Arndt-University of Greifswald, Friedrich-Ludwig-Jahnstrasse 15, 17487 Greifswald, Germany
| | - Katharina Riedel
- />Institute of Microbiology, Ernst-Moritz-Arndt-University of Greifswald, Friedrich-Ludwig-Jahnstrasse 15, 17487 Greifswald, Germany
| | - Petr Baldrian
- />Laboratory of Environmental Microbiology, Institute of Microbiology of the CAS, v. v. i., Průmyslová 595, 252 42 Vestec, Czech Republic
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Logue JB, Findlay SEG, Comte J. Editorial: Microbial Responses to Environmental Changes. Front Microbiol 2015; 6:1364. [PMID: 26696977 PMCID: PMC4667068 DOI: 10.3389/fmicb.2015.01364] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 11/17/2015] [Indexed: 12/03/2022] Open
Affiliation(s)
- Jürg B Logue
- Aquatic Ecology, Department of Biology, Lund University Lund, Sweden ; Science for Life Laboratory Stockholm, Sweden
| | | | - Jérôme Comte
- Département de Biologie, Centre d'études Nordiques - Takuvik and Institut de Biologie Intégrative et des Systèmes, Université Laval Québec, QC, Canada
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Nitrogen Cycling Potential of a Grassland Litter Microbial Community. Appl Environ Microbiol 2015; 81:7012-22. [PMID: 26231641 DOI: 10.1128/aem.02222-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 07/23/2015] [Indexed: 12/13/2022] Open
Abstract
Because microorganisms have different abilities to utilize nitrogen (N) through various assimilatory and dissimilatory pathways, microbial composition and diversity likely influence N cycling in an ecosystem. Terrestrial plant litter decomposition is often limited by N availability; however, little is known about the microorganisms involved in litter N cycling. In this study, we used metagenomics to characterize the potential N utilization of microbial communities in grassland plant litter. The frequencies of sequences associated with eight N cycling pathways differed by several orders of magnitude. Within a pathway, the distributions of these sequences among bacterial orders differed greatly. Many orders within the Actinobacteria and Proteobacteria appeared to be N cycling generalists, carrying genes from most (five or six) of the pathways. In contrast, orders from the Bacteroidetes were more specialized and carried genes for fewer (two or three) pathways. We also investigated how the abundance and composition of microbial N cycling genes differed over time and in response to two global change manipulations (drought and N addition). For many pathways, the abundance and composition of N cycling taxa differed over time, apparently reflecting precipitation patterns. In contrast to temporal variability, simulated global change had minor effects on N cycling potential. Overall, this study provides a blueprint for the genetic potential of N cycle processes in plant litter and a baseline for comparisons to other ecosystems.
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Microbial response to simulated global change is phylogenetically conserved and linked with functional potential. ISME JOURNAL 2015; 10:109-18. [PMID: 26046258 DOI: 10.1038/ismej.2015.96] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/30/2015] [Accepted: 05/03/2015] [Indexed: 11/08/2022]
Abstract
The high diversity of microbial communities hampers predictions about their responses to global change. Here we investigate the potential for using a phylogenetic, trait-based framework to capture the response of bacteria and fungi to global change manipulations. Replicated grassland plots were subjected to 3+ years of drought and nitrogen fertilization. The responses of leaf litter bacteria and fungi to these simulated changes were significantly phylogenetically conserved. Proportional changes in abundance were highly correlated among related organisms, such that relatives with approximately 5% ribosomal DNA genetic distance showed similar responses to the treatments. A microbe's change in relative abundance was significantly correlated between the treatments, suggesting a compromise between numerical abundance in undisturbed environments and resistance to change in general, independent of disturbance type. Lineages in which at least 90% of the microbes shared the same response were circumscribed at a modest phylogenetic depth (τD 0.014-0.021), but significantly larger than randomized simulations predict. In several clades, phylogenetic depth of trait consensus was higher. Fungal response to drought was more conserved than was response to nitrogen fertilization, whereas bacteria responded equally to both treatments. Finally, we show that a bacterium's response to the manipulations is correlated with its potential functional traits (measured here as the number of glycoside hydrolase genes encoding the capacity to degrade different types of carbohydrates). Together, these results suggest that a phylogenetic, trait-based framework may be useful for predicting shifts in microbial composition and functioning in the face of global change.
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Microbiota Dynamics Associated with Environmental Conditions and Potential Roles of Cellulolytic Communities in Traditional Chinese Cereal Starter Solid-State Fermentation. Appl Environ Microbiol 2015; 81:5144-56. [PMID: 26002897 DOI: 10.1128/aem.01325-15] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 05/16/2015] [Indexed: 12/25/2022] Open
Abstract
Traditional Chinese solid-state fermented cereal starters contain highly complex microbial communities and enzymes. Very little is known, however, about the microbial dynamics related to environmental conditions, and cellulolytic communities have never been proposed to exist during cereal starter fermentation. In this study, we performed Illumina MiSeq sequencing combined with PCR-denaturing gradient gel electrophoresis to investigate microbiota, coupled with clone library construction to trace cellulolytic communities in both fermentation stages. A succession of microbial assemblages was observed during the fermentation of starters. Lactobacillales and Saccharomycetales dominated the initial stages, with a continuous decline in relative abundance. However, thermotolerant and drought-resistant Bacillales, Eurotiales, and Mucorales were considerably accelerated during the heating stages, and these organisms dominated until the end of fermentation. Enterobacteriales were consistently ubiquitous throughout the process. For the cellulolytic communities, only the genera Sanguibacter, Beutenbergia, Agrobacterium, and Erwinia dominated the initial fermentation stages. In contrast, stages at high incubation temperature induced the appearance and dominance of Bacillus, Aspergillus, and Mucor. The enzymatic dynamics of amylase and glucoamylase also showed a similar trend, with the activities clearly increased in the first 7 days and subsequently decreased until the end of fermentation. Furthermore, β-glucosidase activity continuously and significantly increased during the fermentation process. Evidently, cellulolytic potential can adapt to environmental conditions by changes in the community structure during the fermentation of starters.
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Temporal variation overshadows the response of leaf litter microbial communities to simulated global change. ISME JOURNAL 2015; 9:2477-89. [PMID: 25978544 DOI: 10.1038/ismej.2015.58] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/06/2015] [Accepted: 03/13/2015] [Indexed: 01/13/2023]
Abstract
Bacteria and fungi drive the decomposition of dead plant biomass (litter), an important step in the terrestrial carbon cycle. Here we investigate the sensitivity of litter microbial communities to simulated global change (drought and nitrogen addition) in a California annual grassland. Using 16S and 28S rDNA amplicon pyrosequencing, we quantify the response of the bacterial and fungal communities to the treatments and compare these results to background, temporal (seasonal and interannual) variability of the communities. We found that the drought and nitrogen treatments both had significant effects on microbial community composition, explaining 2-6% of total compositional variation. However, microbial composition was even more strongly influenced by seasonal and annual variation (explaining 14-39%). The response of microbial composition to drought varied by season, while the effect of the nitrogen addition treatment was constant through time. These compositional responses were similar in magnitude to those seen in microbial enzyme activities and the surrounding plant community, but did not correspond to a consistent effect on leaf litter decomposition rate. Overall, these patterns indicate that, in this ecosystem, temporal variability in the composition of leaf litter microorganisms largely surpasses that expected in a short-term global change experiment. Thus, as for plant communities, future microbial communities will likely be determined by the interplay between rapid, local background variability and slower, global changes.
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