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Wang J, Appidi MR, Burdick LH, Abraham PE, Hettich RL, Pelletier DA, Doktycz MJ. Formation of a constructed microbial community in a nutrient-rich environment indicates bacterial interspecific competition. mSystems 2024; 9:e0000624. [PMID: 38470038 PMCID: PMC11019790 DOI: 10.1128/msystems.00006-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 02/14/2024] [Indexed: 03/13/2024] Open
Abstract
Understanding the organizational principles of microbial communities is essential for interpreting ecosystem stability. Previous studies have investigated the formation of bacterial communities under nutrient-poor conditions or obligate relationships to observe cooperative interactions among different species. How microorganisms form stabilized communities in nutrient-rich environments, without obligate metabolic interdependency for growth, is still not fully disclosed. In this study, three bacterial strains isolated from the Populus deltoides rhizosphere were co-cultured in complex medium, and their growth behavior was tracked. These strains co-exist in mixed culture over serial transfer for multiple growth-dilution cycles. Competition is proposed as an emergent interaction relationship among the three bacteria based on their significantly decreased growth levels. The effects of different initial inoculum ratios, up to three orders of magnitude, on community structure were investigated, and the final compositions of the mixed communities with various starting composition indicate that community structure is not dependent on the initial inoculum ratio. Furthermore, the competitive relationships within the community were not altered by different initial inoculum ratios. The community structure was simulated by generalized Lotka-Volterra and dynamic flux balance analysis to provide mechanistic predictions into emergence of community structure under a nutrient-rich environment. Metaproteomic analyses provide support for the metabolite exchanges predicted by computational modeling and for highly altered physiologies when microbes are grown in co-culture. These findings broaden our understanding of bacterial community dynamics and metabolic diversity in higher-order interactions and could be significant in the management of rhizospheric bacterial communities. IMPORTANCE Bacteria naturally co-exist in multispecies consortia, and the ability to engineer such systems can be useful in biotechnology. Despite this, few studies have been performed to understand how bacteria form a stable community and interact with each other under nutrient-rich conditions. In this study, we investigated the effects of initial inoculum ratios on bacterial community structure using a complex medium and found that the initial inoculum ratio has no significant impact on resultant community structure or on interaction patterns between community members. The microbial population profiles were simulated using computational tools in order to understand intermicrobial relationships and to identify potential metabolic exchanges that occur during stabilization of the bacterial community. Studying microbial community assembly processes is essential for understanding fundamental ecological principles in microbial ecosystems and can be critical in predicting microbial community structure and function.
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Affiliation(s)
- Jia Wang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Manasa R. Appidi
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee, USA
| | - Leah H. Burdick
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Paul E. Abraham
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Robert L. Hettich
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Dale A. Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Mitchel J. Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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2
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Kilner CL, Carrell AA, Wieczynski DJ, Votzke S, DeWitt K, Yammine A, Shaw J, Pelletier DA, Weston DJ, Gibert JP. Temperature and CO 2 interactively drive shifts in the compositional and functional structure of peatland protist communities. Glob Chang Biol 2024; 30:e17203. [PMID: 38433341 DOI: 10.1111/gcb.17203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 01/20/2024] [Accepted: 01/26/2024] [Indexed: 03/05/2024]
Abstract
Microbes affect the global carbon cycle that influences climate change and are in turn influenced by environmental change. Here, we use data from a long-term whole-ecosystem warming experiment at a boreal peatland to answer how temperature and CO2 jointly influence communities of abundant, diverse, yet poorly understood, non-fungi microbial Eukaryotes (protists). These microbes influence ecosystem function directly through photosynthesis and respiration, and indirectly, through predation on decomposers (bacteria and fungi). Using a combination of high-throughput fluid imaging and 18S amplicon sequencing, we report large climate-induced, community-wide shifts in the community functional composition of these microbes (size, shape, and metabolism) that could alter overall function in peatlands. Importantly, we demonstrate a taxonomic convergence but a functional divergence in response to warming and elevated CO2 with most environmental responses being contingent on organismal size: warming effects on functional composition are reversed by elevated CO2 and amplified in larger microbes but not smaller ones. These findings show how the interactive effects of warming and rising CO2 levels could alter the structure and function of peatland microbial food webs-a fragile ecosystem that stores upwards of 25% of all terrestrial carbon and is increasingly threatened by human exploitation.
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Affiliation(s)
- Christopher L Kilner
- Department of Biology, Duke University, Durham, North Carolina, USA
- Bird Conservancy of the Rockies, Fort Collins, Colorado, USA
| | - Alyssa A Carrell
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | | | - Samantha Votzke
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Katrina DeWitt
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Andrea Yammine
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Jonathan Shaw
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Jean P Gibert
- Department of Biology, Duke University, Durham, North Carolina, USA
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3
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Lee JH, Burdick LH, Piatkowski B, Carrell AA, Doktycz MJ, Pelletier DA, Weston DJ. A rapid assay for assessing bacterial effects on Arabidopsis thermotolerance. Plant Methods 2023; 19:63. [PMID: 37386471 DOI: 10.1186/s13007-023-01022-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/01/2023] [Indexed: 07/01/2023]
Abstract
BACKGROUND The role of beneficial microbes in mitigating plant abiotic stress has received considerable attention. However, the lack of a reproducible and relatively high-throughput screen for microbial contributions to plant thermotolerance has greatly limited progress in this area, this slows the discovery of novel beneficial isolates and the processes by which they operate. RESULTS We designed a rapid phenotyping method to assess the effects of bacteria on plant host thermotolerance. After testing multiple growth conditions, a hydroponic system was selected and used to optimize an Arabidopsis heat shock regime and phenotypic evaluation. Arabidopsis seedlings germinated on a PTFE mesh disc were floated onto a 6-well plate containing liquid MS media, then subjected to heat shock at 45 °C for various duration. To characterize phenotype, plants were harvested after four days of recovery to measure chlorophyll content. The method was extended to include bacterial isolates and to quantify bacterial contributions to host plant thermotolerance. As an exemplar, the method was used to screen 25 strains of the plant growth promoting Variovorax spp. for enhanced plant thermotolerance. A follow-up study demonstrated the reproducibility of this assay and led to the discovery of a novel beneficial interaction. CONCLUSIONS This method enables rapid screening of individual bacterial strains for beneficial effects on host plant thermotolerance. The throughput and reproducibility of the system is ideal for testing many genetic variants of Arabidopsis and bacterial strains.
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Affiliation(s)
- Jun Hyung Lee
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd Bldg. 1507, Rm. 214, Oak Ridge, TN, 37831, USA
| | - Leah H Burdick
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd Bldg. 1507, Rm. 214, Oak Ridge, TN, 37831, USA
| | - Bryan Piatkowski
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd Bldg. 1507, Rm. 214, Oak Ridge, TN, 37831, USA
| | - Alyssa A Carrell
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd Bldg. 1507, Rm. 214, Oak Ridge, TN, 37831, USA
| | - Mitchel J Doktycz
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd Bldg. 1507, Rm. 214, Oak Ridge, TN, 37831, USA
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd Bldg. 1507, Rm. 214, Oak Ridge, TN, 37831, USA.
| | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd Bldg. 1507, Rm. 214, Oak Ridge, TN, 37831, USA.
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4
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Wieczynski DJ, Yoshimura KM, Denison ER, Geisen S, DeBruyn JM, Shaw AJ, Weston DJ, Pelletier DA, Wilhelm SW, Gibert JP. Viral infections likely mediate microbial controls on ecosystem responses to global warming. FEMS Microbiol Ecol 2023; 99:7057867. [PMID: 36828391 DOI: 10.1093/femsec/fiad016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/05/2022] [Accepted: 02/22/2023] [Indexed: 02/26/2023] Open
Abstract
Climate change is affecting how energy and matter flow through ecosystems, thereby altering global carbon and nutrient cycles. Microorganisms play a fundamental role in carbon and nutrient cycling and are thus an integral link between ecosystems and climate. Here, we highlight a major black box hindering our ability to anticipate ecosystem climate responses: viral infections within complex microbial food webs. We show how understanding and predicting ecosystem responses to warming could be challenging-if not impossible-without accounting for the direct and indirect effects of viral infections on different microbes (bacteria, archaea, fungi, protists) that together perform diverse ecosystem functions. Importantly, understanding how rising temperatures associated with climate change influence viruses and virus-host dynamics is crucial to this task, yet is severely understudied. In this perspective, we (i) synthesize existing knowledge about virus-microbe-temperature interactions and (ii) identify important gaps to guide future investigations regarding how climate change might alter microbial food web effects on ecosystem functioning. To provide real-world context, we consider how these processes may operate in peatlands-globally significant carbon sinks that are threatened by climate change. We stress that understanding how warming affects biogeochemical cycles in any ecosystem hinges on disentangling complex interactions and temperature responses within microbial food webs.
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Affiliation(s)
| | - Kristin M Yoshimura
- Department of Microbiology, The University of Tennessee, Knoxville, United States
| | - Elizabeth R Denison
- Department of Microbiology, The University of Tennessee, Knoxville, United States
| | - Stefan Geisen
- Netherlands Institute of Ecology, 6708 PB Wageningen, Netherlands
| | - Jennifer M DeBruyn
- Department of Biosystems Engineering and Soil Science, The University of Tennessee, Knoxville, United States
| | - A Jonathan Shaw
- Department of Biology, Duke University, Durham, NC, 27708, United States
| | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, United States
| | - Jean P Gibert
- Department of Biology, Duke University, Durham, NC, 27708, United States
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Dahal S, Hurst GB, Chourey K, Engle NL, Burdick LH, Morrell-Falvey JL, Tschaplinski TJ, Doktycz MJ, Pelletier DA. Mechanism for Utilization of the Populus-Derived Metabolite Salicin by a Pseudomonas- Rahnella Co-Culture. Metabolites 2023; 13:metabo13020140. [PMID: 36837758 PMCID: PMC9959693 DOI: 10.3390/metabo13020140] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 01/18/2023] Open
Abstract
Pseudomonas fluorescens GM16 associates with Populus, a model plant in biofuel production. Populus releases abundant phenolic glycosides such as salicin, but P. fluorescens GM16 cannot utilize salicin, whereas Pseudomonas strains are known to utilize compounds similar to the aglycone moiety of salicin-salicyl alcohol. We propose that the association of Pseudomonas to Populus is mediated by another organism (such as Rahnella aquatilis OV744) that degrades the glucosyl group of salicin. In this study, we demonstrate that in the Rahnella-Pseudomonas salicin co-culture model, Rahnella grows by degrading salicin to glucose 6-phosphate and salicyl alcohol which is secreted out and is subsequently utilized by P. fluorescens GM16 for its growth. Using various quantitative approaches, we elucidate the individual pathways for salicin and salicyl alcohol metabolism present in Rahnella and Pseudomonas, respectively. Furthermore, we were able to establish that the salicyl alcohol cross-feeding interaction between the two strains on salicin medium is carried out through the combination of their respective individual pathways. The research presents one of the potential advantages of salicyl alcohol release by strains such as Rahnella, and how phenolic glycosides could be involved in attracting multiple types of bacteria into the Populus microbiome.
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Affiliation(s)
- Sanjeev Dahal
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
- Genome Science and Technology Program, University of Tennessee, Knoxville, TN 37996, USA
- Department of Chemical Engineering, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Gregory B. Hurst
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Karuna Chourey
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Nancy L. Engle
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Leah H. Burdick
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | | | | | - Mitchel J. Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Dale A. Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
- Correspondence:
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6
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Carrell AA, Lawrence TJ, Cabugao KGM, Carper DL, Pelletier DA, Lee JH, Jawdy SS, Grimwood J, Schmutz J, Hanson PJ, Shaw AJ, Weston DJ. Habitat-adapted microbial communities mediate Sphagnum peatmoss resilience to warming. New Phytol 2022; 234:2111-2125. [PMID: 35266150 PMCID: PMC9310625 DOI: 10.1111/nph.18072] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 02/21/2022] [Indexed: 05/19/2023]
Abstract
Sphagnum peatmosses are fundamental members of peatland ecosystems, where they contribute to the uptake and long-term storage of atmospheric carbon. Warming threatens Sphagnum mosses and is known to alter the composition of their associated microbiome. Here, we use a microbiome transfer approach to test if microbiome thermal origin influences host plant thermotolerance. We leveraged an experimental whole-ecosystem warming study to collect field-grown Sphagnum, mechanically separate the associated microbiome and then transfer onto germ-free laboratory Sphagnum for temperature experiments. Host and microbiome dynamics were assessed with growth analysis, Chla fluorescence imaging, metagenomics, metatranscriptomics and 16S rDNA profiling. Microbiomes originating from warming field conditions imparted enhanced thermotolerance and growth recovery at elevated temperatures. Metagenome and metatranscriptome analyses revealed that warming altered microbial community structure in a manner that induced the plant heat shock response, especially the HSP70 family and jasmonic acid production. The heat shock response was induced even without warming treatment in the laboratory, suggesting that the warm-microbiome isolated from the field provided the host plant with thermal preconditioning. Our results demonstrate that microbes, which respond rapidly to temperature alterations, can play key roles in host plant growth response to rapidly changing environments.
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Affiliation(s)
- Alyssa A. Carrell
- Biosciences DivisionOak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37831USA
| | - Travis J. Lawrence
- Biosciences DivisionOak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37831USA
| | - Kristine Grace M. Cabugao
- Bredesen Center for Interdisciplinary Research and Graduate EducationUniversity of Tennessee1502 Cumberland Ave.KnoxvilleTN37996USA
| | - Dana L. Carper
- Biosciences DivisionOak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37831USA
| | - Dale A. Pelletier
- Biosciences DivisionOak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37831USA
| | - Jun Hyung Lee
- Biosciences DivisionOak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37831USA
| | - Sara S. Jawdy
- Biosciences DivisionOak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37831USA
| | - Jane Grimwood
- HudsonAlpha Institute for Biotechnology601 Genome WayHuntsvilleAL35806USA
- Department of Energy Joint Genome InstituteLawrence Berkeley National Lab1 Cyclotron Rd.BerkeleyCA94720USA
| | - Jeremy Schmutz
- HudsonAlpha Institute for Biotechnology601 Genome WayHuntsvilleAL35806USA
- Department of Energy Joint Genome InstituteLawrence Berkeley National Lab1 Cyclotron Rd.BerkeleyCA94720USA
| | - Paul J. Hanson
- Environmental Sciences DivisionOak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37831USA
| | | | - David J. Weston
- Biosciences DivisionOak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37831USA
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7
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Liang X, Zhu N, Johs A, Chen H, Pelletier DA, Zhang L, Yin X, Gao Y, Zhao J, Gu B. Mercury Reduction, Uptake, and Species Transformation by Freshwater Alga Chlorella vulgaris under Sunlit and Dark Conditions. Environ Sci Technol 2022; 56:4961-4969. [PMID: 35389633 DOI: 10.1021/acs.est.1c06558] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
As a major entry point of mercury (Hg) to aquatic food webs, algae play an important role in taking up and transforming Hg species in aquatic ecosystems. However, little is known how and to what extent Hg reduction, uptake, and species transformations are mediated by algal cells and their exudates, algal organic matter (AOM), under either sunlit or dark conditions. Here, using Chlorella vulgaris (CV) as one of the most prevalent freshwater model algal species, we show that solar irradiation could enhance the reduction of mercuric Hg(II) to elemental Hg(0) by both CV cells and AOM. AOM reduced more Hg(II) than algal cells themselves due to cell surface adsorption and uptake of Hg(II) inside the cells under solar irradiation. Synchrotron radiation X-ray absorption near-edge spectroscopy (SR-XANES) analyses indicate that sunlight facilitated the transformation of Hg to less bioavailable species, such as β-HgS and Hg-phytochelatins, compared to Hg(Cysteine)2-like species formed in algal cells in the dark. These findings highlight important functional roles and potential mechanisms of algae in Hg reduction and immobilization under varying lighting conditions and how these processes may modulate Hg cycling and bioavailability in the aquatic environment.
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Affiliation(s)
- Xujun Liang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- School of Resources and Environment Science, Quanzhou Normal University, Quanzhou 362000, China
| | - Nali Zhu
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Alexander Johs
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Hongmei Chen
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Dale A Pelletier
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Lijie Zhang
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Xixiang Yin
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yuxi Gao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Jiating Zhao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Baohua Gu
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee 37996, United States
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8
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Shrestha HK, Appidi MR, Villalobos Solis MI, Wang J, Carper DL, Burdick L, Pelletier DA, Doktycz MJ, Hettich RL, Abraham PE. Metaproteomics reveals insights into microbial structure, interactions, and dynamic regulation in defined communities as they respond to environmental disturbance. BMC Microbiol 2021; 21:308. [PMID: 34749649 PMCID: PMC8574000 DOI: 10.1186/s12866-021-02370-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
Background Microbe-microbe interactions between members of the plant rhizosphere are important but remain poorly understood. A more comprehensive understanding of the molecular mechanisms used by microbes to cooperate, compete, and persist has been challenging because of the complexity of natural ecosystems and the limited control over environmental factors. One strategy to address this challenge relies on studying complexity in a progressive manner, by first building a detailed understanding of relatively simple subsets of the community and then achieving high predictive power through combining different building blocks (e.g., hosts, community members) for different environments. Herein, we coupled this reductionist approach with high-resolution mass spectrometry-based metaproteomics to study molecular mechanisms driving community assembly, adaptation, and functionality for a defined community of ten taxonomically diverse bacterial members of Populus deltoides rhizosphere co-cultured either in a complex or defined medium. Results Metaproteomics showed this defined community assembled into distinct microbiomes based on growth media that eventually exhibit composition and functional stability over time. The community grown in two different media showed variation in composition, yet both were dominated by only a few microbial strains. Proteome-wide interrogation provided detailed insights into the functional behavior of each dominant member as they adjust to changing community compositions and environments. The emergence and persistence of select microbes in these communities were driven by specialization in strategies including motility, antibiotic production, altered metabolism, and dormancy. Protein-level interrogation identified post-translational modifications that provided additional insights into regulatory mechanisms influencing microbial adaptation in the changing environments. Conclusions This study provides high-resolution proteome-level insights into our understanding of microbe-microbe interactions and highlights specialized biological processes carried out by specific members of assembled microbiomes to compete and persist in changing environmental conditions. Emergent properties observed in these lower complexity communities can then be re-evaluated as more complex systems are studied and, when a particular property becomes less relevant, higher-order interactions can be identified. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02370-4.
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Affiliation(s)
- Him K Shrestha
- Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, Tennessee, United States.,Department of Genome Science and Technology, University of Tennessee-Knoxville, 37996, Knoxville, Tennessee, United States
| | - Manasa R Appidi
- Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, Tennessee, United States.,Department of Genome Science and Technology, University of Tennessee-Knoxville, 37996, Knoxville, Tennessee, United States
| | | | - Jia Wang
- Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, Tennessee, United States
| | - Dana L Carper
- Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, Tennessee, United States
| | - Leah Burdick
- Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, Tennessee, United States
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, Tennessee, United States
| | - Mitchel J Doktycz
- Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, Tennessee, United States
| | - Robert L Hettich
- Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, Tennessee, United States
| | - Paul E Abraham
- Biosciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, Tennessee, United States.
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9
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Wang J, Carper DL, Burdick LH, Shrestha HK, Appidi MR, Abraham PE, Timm CM, Hettich RL, Pelletier DA, Doktycz MJ. Formation, characterization and modeling of emergent synthetic microbial communities. Comput Struct Biotechnol J 2021; 19:1917-1927. [PMID: 33995895 PMCID: PMC8079826 DOI: 10.1016/j.csbj.2021.03.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/22/2021] [Accepted: 03/25/2021] [Indexed: 01/04/2023] Open
Abstract
Microbial communities colonize plant tissues and contribute to host function. How these communities form and how individual members contribute to shaping the microbial community are not well understood. Synthetic microbial communities, where defined individual isolates are combined, can serve as valuable model systems for uncovering the organizational principles of communities. Using genome-defined organisms, systematic analysis by computationally-based network reconstruction can lead to mechanistic insights and the metabolic interactions between species. In this study, 10 bacterial strains isolated from the Populus deltoides rhizosphere were combined and passaged in two different media environments to form stable microbial communities. The membership and relative abundances of the strains stabilized after around 5 growth cycles and resulted in just a few dominant strains that depended on the medium. To unravel the underlying metabolic interactions, flux balance analysis was used to model microbial growth and identify potential metabolic exchanges involved in shaping the microbial communities. These analyses were complemented by growth curves of the individual isolates, pairwise interaction screens, and metaproteomics of the community. A fast growth rate is identified as one factor that can provide an advantage for maintaining presence in the community. Final community selection can also depend on selective antagonistic relationships and metabolic exchanges. Revealing the mechanisms of interaction among plant-associated microorganisms provides insights into strategies for engineering microbial communities that can potentially increase plant growth and disease resistance. Further, deciphering the membership and metabolic potentials of a bacterial community will enable the design of synthetic communities with desired biological functions.
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Affiliation(s)
- Jia Wang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Dana L. Carper
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Leah H. Burdick
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Him K. Shrestha
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, USA
| | - Manasa R. Appidi
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, USA
| | - Paul E. Abraham
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Collin M. Timm
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Robert L. Hettich
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Dale A. Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Corresponding authors.
| | - Mitchel J. Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Corresponding authors.
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10
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Xie M, Zhang J, Yao T, Bryan AC, Pu Y, Labbé J, Pelletier DA, Engle N, Morrell‐Falvey JL, Schmutz J, Ragauskas AJ, Tschaplinski TJ, Chen F, Tuskan GA, Muchero W, Chen J. Arabidopsis C-terminal binding protein ANGUSTIFOLIA modulates transcriptional co-regulation of MYB46 and WRKY33. New Phytol 2020; 228:1627-1639. [PMID: 32706429 PMCID: PMC7692920 DOI: 10.1111/nph.16826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 06/26/2020] [Indexed: 05/04/2023]
Abstract
The apparent antagonism between salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) signalling resulting in trade-offs between defence against (hemi)biotrophic and necrotrophic pathogens has been widely described across multiple plant species. However, the underlying mechanism remains to be fully established. The molecular and cellular functions of ANGUSTIFOLIA (AN) were characterised, and its role in regulating the pathogenic response was studied in Arabidopsis. We demonstrated that AN, a plant homologue of mammalian C-TERMINAL BINDING PROTEIN (CtBP), antagonistically regulates plant resistance to the hemibiotrophic pathogen Pseudomonas syringae and the necrotrophic pathogen Botrytis cinerea. Consistent with phenotypic observations, transcription of genes involved in SA and JA/ET pathways was antagonistically regulated by AN. By interacting with another nuclear protein TYROSYL-DNA PHOSPHODIESTERASE1 (TDP1), AN imposes transcriptional repression on MYB46, encoding a transcriptional activator of PHENYLALANINE AMMONIA-LYASE (PAL) genes which are required for SA biosynthesis, while releasing TDP1-imposed transcriptional repression on WRKY33, a master regulator of the JA/ET signalling pathway. These findings demonstrate that transcriptional co-regulation of MYB46 and WRKY33 by AN mediates the coordination of SA and JA/ET pathways to optimise defences against (hemi)biotrophic and necrotrophic pathogens.
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Affiliation(s)
- Meng Xie
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
- Department of Plant SciencesUniversity of TennesseeKnoxvilleTN37996USA
- Biology DepartmentBrookhaven National LaboratoryUptonNY11973USA
| | - Jin Zhang
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Tao Yao
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Anthony C. Bryan
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Yunqiao Pu
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Jessy Labbé
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Dale A. Pelletier
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Nancy Engle
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | | | - Jeremy Schmutz
- US Department of Energy Joint Genome InstituteBerkeleyCA94720USA
- HudsonAlpha Institute for BiotechnologyHuntsvilleAL35806USA
| | - Arthur J. Ragauskas
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
- UT‐ORNL Joint Institute for Biological ScienceOak Ridge National LaboratoryOak RidgeTN37831USA
- Department of Chemical and Biomolecular Engineering & Department of Forestry, Wildlife, and FisheriesUniversity of TennesseeKnoxvilleTN37996USA
| | - Timothy J. Tschaplinski
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Feng Chen
- Department of Plant SciencesUniversity of TennesseeKnoxvilleTN37996USA
| | - Gerald A. Tuskan
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Wellington Muchero
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Jin‐Gui Chen
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- BioEnergy Science CenterOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
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Saint-Vincent PMB, Ridout M, Engle NL, Lawrence TJ, Yeary ML, Tschaplinski TJ, Newcombe G, Pelletier DA. Isolation, Characterization, and Pathogenicity of Two Pseudomonas syringae Pathovars from Populus trichocarpa Seeds. Microorganisms 2020; 8:microorganisms8081137. [PMID: 32731357 PMCID: PMC7465253 DOI: 10.3390/microorganisms8081137] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 11/16/2022] Open
Abstract
Pseudomonas syringae is a ubiquitous plant pathogen, infecting both woody and herbaceous plants and resulting in devastating agricultural crop losses. Characterized by a remarkable specificity for plant hosts, P. syringae pathovars utilize a number of virulence factors including the type III secretion system and effector proteins to elicit disease in a particular host species. Here, two Pseudomonas syringae strains were isolated from diseased Populustrichocarpa seeds. The pathovars were capable of inhibiting poplar seed germination and were selective for the Populus genus. Sequencing of the newly described organisms revealed similarity to phylogroup II pathogens and genomic regions associated with woody host-associated plant pathogens, as well as genes for specific virulence factors. The host response to infection, as revealed through metabolomics, is the induction of the stress response through the accumulation of higher-order salicylates. Combined with necrosis on leaf surfaces, the plant appears to quickly respond by isolating infected tissues and mounting an anti-inflammatory defense. This study improves our understanding of the initial host response to epiphytic pathogens in Populus and provides a new model system for studying the effects of a bacterial pathogen on a woody host plant in which both organisms are fully genetically sequenced.
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Affiliation(s)
- Patricia MB Saint-Vincent
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; (P.M.S.-V.); (N.L.E.); (T.J.L.); (M.L.Y.); (T.J.T.)
- Geologic and Environmental Systems Directorate, National Energy Technology Laboratory, Pittsburgh, PA 15236, USA
| | - Mary Ridout
- Department of Forest, Rangeland and Fire Sciences, University of Idaho, Moscow, ID 83844, USA; (M.R.); (G.N.)
| | - Nancy L. Engle
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; (P.M.S.-V.); (N.L.E.); (T.J.L.); (M.L.Y.); (T.J.T.)
| | - Travis J. Lawrence
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; (P.M.S.-V.); (N.L.E.); (T.J.L.); (M.L.Y.); (T.J.T.)
| | - Meredith L. Yeary
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; (P.M.S.-V.); (N.L.E.); (T.J.L.); (M.L.Y.); (T.J.T.)
| | - Timothy J. Tschaplinski
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; (P.M.S.-V.); (N.L.E.); (T.J.L.); (M.L.Y.); (T.J.T.)
| | - George Newcombe
- Department of Forest, Rangeland and Fire Sciences, University of Idaho, Moscow, ID 83844, USA; (M.R.); (G.N.)
| | - Dale A. Pelletier
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; (P.M.S.-V.); (N.L.E.); (T.J.L.); (M.L.Y.); (T.J.T.)
- Correspondence:
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12
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Carper DL, Lawrence TJ, Carrell AA, Pelletier DA, Weston DJ. DISCo-microbe: design of an identifiable synthetic community of microbes. PeerJ 2020; 8:e8534. [PMID: 32149021 PMCID: PMC7049465 DOI: 10.7717/peerj.8534] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 01/08/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Microbiomes are extremely important for their host organisms, providing many vital functions and extending their hosts' phenotypes. Natural studies of host-associated microbiomes can be difficult to interpret due to the high complexity of microbial communities, which hinders our ability to track and identify individual members along with the many factors that structure or perturb those communities. For this reason, researchers have turned to synthetic or constructed communities in which the identities of all members are known. However, due to the lack of tracking methods and the difficulty of creating a more diverse and identifiable community that can be distinguished through next-generation sequencing, most such in vivo studies have used only a few strains. RESULTS To address this issue, we developed DISCo-microbe, a program for the design of an identifiable synthetic community of microbes for use in in vivo experimentation. The program is composed of two modules; (1) create, which allows the user to generate a highly diverse community list from an input DNA sequence alignment using a custom nucleotide distance algorithm, and (2) subsample, which subsamples the community list to either represent a number of grouping variables, including taxonomic proportions, or to reach a user-specified maximum number of community members. As an example, we demonstrate the generation of a synthetic microbial community that can be distinguished through amplicon sequencing. The synthetic microbial community in this example consisted of 2,122 members from a starting DNA sequence alignment of 10,000 16S rRNA sequences from the Ribosomal Database Project. We generated simulated Illumina sequencing data from the constructed community and demonstrate that DISCo-microbe is capable of designing diverse communities with members distinguishable by amplicon sequencing. Using the simulated data we were able to recover sequences from between 97-100% of community members using two different post-processing workflows. Furthermore, 97-99% of sequences were assigned to a community member with zero sequences being misidentified. We then subsampled the community list using taxonomic proportions to mimic a natural plant host-associated microbiome, ultimately yielding a diverse community of 784 members. CONCLUSIONS DISCo-microbe can create a highly diverse community list of microbes that can be distinguished through 16S rRNA gene sequencing, and has the ability to subsample (i.e., design) the community for the desired number of members and taxonomic proportions. Although developed for bacteria, the program allows for any alignment input from any taxonomic group, making it broadly applicable. The software and data are freely available from GitHub (https://github.com/dlcarper/DISCo-microbe) and Python Package Index (PYPI).
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Affiliation(s)
- Dana L. Carper
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States of America
| | - Travis J. Lawrence
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States of America
| | - Alyssa A. Carrell
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States of America
- Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee—Knoxville, Knoxville, TN, United States of America
| | - Dale A. Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States of America
| | - David J. Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States of America
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13
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Henning JA, Weston DJ, Pelletier DA, Timm CM, Jawdy SS, Classen AT. Relatively rare root endophytic bacteria drive plant resource allocation patterns and tissue nutrient concentration in unpredictable ways. Am J Bot 2019; 106:1423-1434. [PMID: 31657872 DOI: 10.1002/ajb2.1373] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/06/2019] [Indexed: 05/12/2023]
Abstract
PREMISE Plant endophytic bacterial strains can influence plant traits such as leaf area and root length. Yet, the influence of more complex bacterial communities in regulating overall plant phenotype is less explored. Here, in two complementary experiments, we tested whether we can predict plant phenotype response to changes in microbial community composition. METHODS In the first study, we inoculated a single genotype of Populus deltoides with individual root endophytic bacteria and measured plant phenotype. Next, data from this single inoculation were used to predict phenotypic traits after mixed three-strain community inoculations, which we tested in the second experiment. RESULTS By itself, each bacterial endophyte significantly but weakly altered plant phenotype relative to noninoculated plants. In a mixture, bacterial strain Burkholderia BT03, constituted at least 98% of community relative abundance. Yet, plant resource allocation and tissue nutrient concentrations were disproportionately influenced by Pseudomonas sp. GM17, GM30, and GM41. We found a 10% increase in leaf mass fraction and an 11% decrease in root mass fraction when replacing Pseudomonas GM17 with GM41 in communities containing both Pseudomonas GM30 and Burkholderia BT03. CONCLUSIONS Our results indicate that interactions among endophytic bacteria may drive plant phenotype over the contribution of each strain individually. Additionally, we have shown that low-abundance strains contribute to plant phenotype challenging the assumption that the dominant strains will drive plant function.
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Affiliation(s)
- Jeremiah A Henning
- Ecology & Evolutionary Biology, University of Tennessee, 569 Dabney Hall, 1416 Circle Drive, Knoxville, TN, 37996, USA
- Ecology, Evolution, and Behavior, University of Minnesota, 140 Gortner Avenue, St. Paul, MN, 55108, USA
| | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Collin M Timm
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Biosciences, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD, 20723, USA
| | - Sara S Jawdy
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Aimée T Classen
- Ecology & Evolutionary Biology, University of Tennessee, 569 Dabney Hall, 1416 Circle Drive, Knoxville, TN, 37996, USA
- The Rubenstein School of Environment & Natural Resources, University of Vermont, Burlington, VT, 05405, USA
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14
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Carrell AA, Kolton M, Glass JB, Pelletier DA, Warren MJ, Kostka JE, Iversen CM, Hanson PJ, Weston DJ. Experimental warming alters the community composition, diversity, and N 2 fixation activity of peat moss (Sphagnum fallax) microbiomes. Glob Chang Biol 2019; 25:2993-3004. [PMID: 31148286 PMCID: PMC6852288 DOI: 10.1111/gcb.14715] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 05/17/2019] [Accepted: 05/24/2019] [Indexed: 05/19/2023]
Abstract
Sphagnum-dominated peatlands comprise a globally important pool of soil carbon (C) and are vulnerable to climate change. While peat mosses of the genus Sphagnum are known to harbor diverse microbial communities that mediate C and nitrogen (N) cycling in peatlands, the effects of climate change on Sphagnum microbiome composition and functioning are largely unknown. We investigated the impacts of experimental whole-ecosystem warming on the Sphagnum moss microbiome, focusing on N2 fixing microorganisms (diazotrophs). To characterize the microbiome response to warming, we performed next-generation sequencing of small subunit (SSU) rRNA and nitrogenase (nifH) gene amplicons and quantified rates of N2 fixation activity in Sphagnum fallax individuals sampled from experimental enclosures over 2 years in a northern Minnesota, USA bog. The taxonomic diversity of overall microbial communities and diazotroph communities, as well as N2 fixation rates, decreased with warming (p < 0.05). Following warming, diazotrophs shifted from a mixed community of Nostocales (Cyanobacteria) and Rhizobiales (Alphaproteobacteria) to predominance of Nostocales. Microbiome community composition differed between years, with some diazotroph populations persisting while others declined in relative abundance in warmed plots in the second year. Our results demonstrate that warming substantially alters the community composition, diversity, and N2 fixation activity of peat moss microbiomes, which may ultimately impact host fitness, ecosystem productivity, and C storage potential in peatlands.
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Affiliation(s)
- Alyssa A. Carrell
- Bredesen Center for Interdisciplinary Research and Graduate EducationUniversity of TennesseeKnoxvilleTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Max Kolton
- School of BiologyGeorgia Institute of TechnologyAtlantaGeorgia
| | - Jennifer B. Glass
- School of Earth and Atmospheric SciencesGeorgia Institute of TechnologyAtlantaGeorgia
| | | | - Melissa J. Warren
- School of Earth and Atmospheric SciencesGeorgia Institute of TechnologyAtlantaGeorgia
- Present address:
CH2MAtlantaGeorgia30328USA
| | - Joel E. Kostka
- School of BiologyGeorgia Institute of TechnologyAtlantaGeorgia
- School of Earth and Atmospheric SciencesGeorgia Institute of TechnologyAtlantaGeorgia
| | - Colleen M. Iversen
- Environmental Sciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
- Climate Change Science Institute, Oak Ridge National LaboratoryOak RidgeTennessee
| | - Paul J. Hanson
- Environmental Sciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
- Climate Change Science Institute, Oak Ridge National LaboratoryOak RidgeTennessee
| | - David J. Weston
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
- Climate Change Science Institute, Oak Ridge National LaboratoryOak RidgeTennessee
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15
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An J, Zhang L, Lu X, Pelletier DA, Pierce EM, Johs A, Parks JM, Gu B. Mercury Uptake by Desulfovibrio desulfuricans ND132: Passive or Active? Environ Sci Technol 2019; 53:6264-6272. [PMID: 31075193 DOI: 10.1021/acs.est.9b00047] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Recent studies have identified HgcAB proteins as being responsible for mercury [Hg(II)] methylation by certain anaerobic microorganisms. However, it remains controversial whether microbes take up Hg(II) passively or actively. Here, we examine the dynamics of concurrent Hg(II) adsorption, uptake, and methylation by both viable and inactivated cells (heat-killed or starved) or spheroplasts of the sulfate-reducing bacterium Desulfovibrio desulfuricans ND132 in laboratory incubations. We show that, without addition of thiols, >60% of the added Hg(II) (25 nM) was taken up passively in 48 h by live and inactivated cells and also by cells treated with the proton gradient uncoupler, carbonylcyanide-3-chlorophenylhydrazone (CCCP). Inactivation abolished Hg(II) methylation, but the cells continued taking up Hg(II), likely through competitive binding or ligand exchange of Hg(II) by intracellular proteins or thiol-containing cellular components. Similarly, treatment with CCCP impaired the ability of spheroplasts to methylate Hg(II) but did not stop Hg(II) uptake. Spheroplasts showed a greater capacity to adsorb Hg(II) than whole cells, and the level of cytoplasmic membrane-bound Hg(II) correlated well with MeHg production, as Hg(II) methylation is associated with cytoplasmic HgcAB. Our results indicate that active metabolism is not required for cellular Hg(II) uptake, thereby providing an improved understanding of Hg(II) bioavailability for methylation.
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Affiliation(s)
- Jing An
- Environmental Sciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology , Chinese Academy of Sciences , Shenyang 110016 , China
| | - Lijie Zhang
- Environmental Sciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Xia Lu
- Environmental Sciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Dale A Pelletier
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Eric M Pierce
- Environmental Sciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Alexander Johs
- Environmental Sciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Jerry M Parks
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Baohua Gu
- Environmental Sciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
- Department of Biosystems Engineering and Soil Science , University of Tennessee , Knoxville , Tennessee 37996 , United States
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16
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Bortniak VL, Pelletier DA, Newman JD. Chryseobacterium populi sp. nov., isolated from Populus deltoides endosphere. Int J Syst Evol Microbiol 2019; 69:356-362. [DOI: 10.1099/ijsem.0.003140] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Victoria L. Bortniak
- 1Biology Department, Lycoming College, Williamsport PA 17701, USA
- †Present address: Trivergent Health Alliance, MSO, Meritus Medical Center, Hagerstown, MD 21742, USA
| | - Dale A. Pelletier
- 2Biosciences Division, Oak Ridge National Laboratory, 1 Bethyl Valley Rd. MS-6036, Oak Ridge, TN 37831, USA
| | - Jeffrey D. Newman
- 3Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein 9300, Republic of South Africa
- 1Biology Department, Lycoming College, Williamsport PA 17701, USA
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17
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Aufrecht JA, Timm CM, Bible A, Morrell-Falvey JL, Pelletier DA, Doktycz MJ, Retterer ST. Microfluidics: Quantifying the Spatiotemporal Dynamics of Plant Root Colonization by Beneficial Bacteria in a Microfluidic Habitat (Adv. Biosys. 6/2018). ACTA ACUST UNITED AC 2018. [DOI: 10.1002/adbi.201870051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jayde A. Aufrecht
- Bioscience Division; Oak Ridge National Laboratory; Oak Ridge TN 37831 USA
- Bredesen Center; University of Tennessee; Knoxville TN 37996 USA
| | - Collin M. Timm
- Bioscience Division; Oak Ridge National Laboratory; Oak Ridge TN 37831 USA
| | - Amber Bible
- Biochemistry and Cellular and Molecular Biology; University of Tennessee; Knoxville TN 37996 USA
| | - Jennifer L. Morrell-Falvey
- Bioscience Division; Oak Ridge National Laboratory; Oak Ridge TN 37831 USA
- Bredesen Center; University of Tennessee; Knoxville TN 37996 USA
- Biochemistry and Cellular and Molecular Biology; University of Tennessee; Knoxville TN 37996 USA
| | - Dale A. Pelletier
- Bioscience Division; Oak Ridge National Laboratory; Oak Ridge TN 37831 USA
| | - Mitchel J. Doktycz
- Bioscience Division; Oak Ridge National Laboratory; Oak Ridge TN 37831 USA
- Bredesen Center; University of Tennessee; Knoxville TN 37996 USA
- Center for Nanophase Materials Sciences; Oak Ridge National Laboratory; Oak Ridge TN 37831 USA
| | - Scott T. Retterer
- Bioscience Division; Oak Ridge National Laboratory; Oak Ridge TN 37831 USA
- Bredesen Center; University of Tennessee; Knoxville TN 37996 USA
- Center for Nanophase Materials Sciences; Oak Ridge National Laboratory; Oak Ridge TN 37831 USA
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18
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Aufrecht JA, Timm CM, Bible A, Morrell‐Falvey JL, Pelletier DA, Doktycz MJ, Retterer ST. Quantifying the Spatiotemporal Dynamics of Plant Root Colonization by Beneficial Bacteria in a Microfluidic Habitat. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/adbi.201800048] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jayde A. Aufrecht
- Bioscience Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA
- Bredesen Center University of Tennessee Knoxville TN 37996 USA
| | - Collin M. Timm
- Bioscience Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Amber Bible
- Biochemistry and Cellular and Molecular Biology University of Tennessee Knoxville TN 37996 USA
| | - Jennifer L. Morrell‐Falvey
- Bioscience Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA
- Bredesen Center University of Tennessee Knoxville TN 37996 USA
- Biochemistry and Cellular and Molecular Biology University of Tennessee Knoxville TN 37996 USA
| | - Dale A. Pelletier
- Bioscience Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Mitchel J. Doktycz
- Bioscience Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA
- Bredesen Center University of Tennessee Knoxville TN 37996 USA
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Scott T. Retterer
- Bioscience Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA
- Bredesen Center University of Tennessee Knoxville TN 37996 USA
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
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19
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Hasim S, Allison DP, Mendez B, Farmer AT, Pelletier DA, Retterer ST, Campagna SR, Reynolds TB, Doktycz MJ. Elucidating Duramycin's Bacterial Selectivity and Mode of Action on the Bacterial Cell Envelope. Front Microbiol 2018; 9:219. [PMID: 29491859 PMCID: PMC5817074 DOI: 10.3389/fmicb.2018.00219] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/30/2018] [Indexed: 11/25/2022] Open
Abstract
The use of naturally occurring antimicrobial peptides provides a promising route to selectively target pathogenic agents and to shape microbiome structure. Lantibiotics, such as duramycin, are one class of bacterially produced peptidic natural products that can selectively inhibit the growth of other bacteria. However, despite longstanding characterization efforts, the microbial selectivity and mode of action of duramycin are still obscure. We describe here a suite of biological, chemical, and physical characterizations that shed new light on the selective and mechanistic aspects of duramycin activity. Bacterial screening assays have been performed using duramycin and Populus-derived bacterial isolates to determine species selectivity. Lipidomic profiles of selected resistant and sensitive strains show that the sensitivity of Gram-positive bacteria depends on the presence of phosphatidylethanolamine (PE) in the cell membrane. Further the surface and interface morphology were studied by high resolution atomic force microscopy and showed a progression of cellular changes in the cell envelope after treatment with duramycin for the susceptible bacterial strains. Together, these molecular and cellular level analyses provide insight into duramycin’s mode of action and a better understanding of its selectivity.
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Affiliation(s)
- Sahar Hasim
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - David P Allison
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, United States
| | - Berlin Mendez
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Abigail T Farmer
- Department of Chemistry, University of Tennessee, Knoxville, TN, United States
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Scott T Retterer
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Shawn R Campagna
- Department of Chemistry, University of Tennessee, Knoxville, TN, United States
| | - Todd B Reynolds
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Mitchel J Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, United States
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20
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Levy A, Salas Gonzalez I, Mittelviefhaus M, Clingenpeel S, Herrera Paredes S, Miao J, Wang K, Devescovi G, Stillman K, Monteiro F, Rangel Alvarez B, Lundberg DS, Lu TY, Lebeis S, Jin Z, McDonald M, Klein AP, Feltcher ME, Rio TG, Grant SR, Doty SL, Ley RE, Zhao B, Venturi V, Pelletier DA, Vorholt JA, Tringe SG, Woyke T, Dangl JL. Genomic features of bacterial adaptation to plants. Nat Genet 2017; 50:138-150. [PMID: 29255260 PMCID: PMC5957079 DOI: 10.1038/s41588-017-0012-9] [Citation(s) in RCA: 280] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 11/10/2017] [Indexed: 01/10/2023]
Abstract
Plants intimately associate with diverse bacteria. Plant-associated (PA) bacteria have ostensibly evolved genes enabling adaptation to the plant environment. However, the identities of such genes are mostly unknown and their functions are poorly characterized. We sequenced 484 genomes of bacterial isolates from roots of Brassicaceae, poplar, and maize. We then compared 3837 bacterial genomes to identify thousands of PA gene clusters. Genomes of PA bacteria encode more carbohydrate metabolism functions and fewer mobile elements than related non-plant associated genomes. We experimentally validated candidates from two sets of PA genes, one involved in plant colonization, the other serving in microbe-microbe competition between PA bacteria. We also identified 64 PA protein domains that potentially mimic plant domains; some are shared with PA fungi and oomycetes. This work expands the genome-based understanding of plant-microbe interactions and provides leads for efficient and sustainable agriculture through microbiome engineering.
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Affiliation(s)
- Asaf Levy
- DOE Joint Genome Institute, Walnut Creek, CA, USA
| | - Isai Salas Gonzalez
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | | | | | - Sur Herrera Paredes
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA.,Department of Biology, Stanford University, Stanford, CA, USA
| | - Jiamin Miao
- Department of Horticulture, Virginia Tech, Blacksburg, VA, USA.,The Grassland College, Gansu Agricultural University, Lanzhou, Gansu, China
| | - Kunru Wang
- Department of Horticulture, Virginia Tech, Blacksburg, VA, USA
| | - Giulia Devescovi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Freddy Monteiro
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | | | - Derek S Lundberg
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Tse-Yuan Lu
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Sarah Lebeis
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Zhao Jin
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Meredith McDonald
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Andrew P Klein
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Meghan E Feltcher
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA.,BD Technologies and Innovation, Research Triangle Park, NC, USA
| | | | - Sarah R Grant
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
| | - Sharon L Doty
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA, USA
| | - Ruth E Ley
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Bingyu Zhao
- Department of Horticulture, Virginia Tech, Blacksburg, VA, USA
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | | | - Susannah G Tringe
- DOE Joint Genome Institute, Walnut Creek, CA, USA. .,School of Natural Sciences, University of California, Merced, Merced, CA, USA.
| | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, CA, USA. .,School of Natural Sciences, University of California, Merced, Merced, CA, USA.
| | - Jeffery L Dangl
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA. .,Howard Hughes Medical Institute, Chevy Chase, MD, USA. .,The Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, NC, USA. .,Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, USA.
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21
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Cabugao KG, Timm CM, Carrell AA, Childs J, Lu TYS, Pelletier DA, Weston DJ, Norby RJ. Root and Rhizosphere Bacterial Phosphatase Activity Varies with Tree Species and Soil Phosphorus Availability in Puerto Rico Tropical Forest. Front Plant Sci 2017; 8:1834. [PMID: 29163572 PMCID: PMC5670114 DOI: 10.3389/fpls.2017.01834] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/10/2017] [Indexed: 05/29/2023]
Abstract
Tropical forests generally occur on highly weathered soils that, in combination with the immobility of phosphorus (P), often result in soils lacking orthophosphate, the form of P most easily metabolized by plants and microbes. In these soils, mineralization of organic P can be the major source for orthophosphate. Both plants and microbes encode for phosphatases capable of mineralizing a range of organic P compounds. However, the activity of these enzymes depends on several edaphic factors including P availability, tree species, and microbial communities. Thus, phosphatase activity in both roots and the root microbial community constitute an important role in P mineralization and P nutrient dynamics that are not well studied in tropical forests. To relate phosphatase activity of roots and bacteria in tropical forests, we measured phosphatase activity in roots and bacterial isolates as well as bacterial community composition from the rhizosphere. Three forests in the Luquillo Mountains of Puerto Rico were selected to represent a range of soil P availability as measured using the resin P method. Within each site, a minimum of three tree species were chosen to sample. Root and bacterial phosphatase activity were both measured using a colorimetric assay with para-nitrophenyl phosphate as a substrate for the phosphomonoesterase enzyme. Both root and bacterial phosphatase were chiefly influenced by tree species. Though tree species was the only significant factor in root phosphatase activity, there was a negative trend between soil P availability and phosphatase activity in linear regressions of average root phosphatase and resin P. Permutational multivariate analysis of variance of bacterial community composition based on 16S amplicon sequencing indicated that bacterial composition was strongly controlled by soil P availability (p-value < 0.05). These results indicate that although root and bacterial phosphatase activity were influenced by tree species; bacterial community composition was chiefly influenced by P availability. Although the sample size is limited given the tremendous diversity of tropical forests, our study indicates the importance of roots and bacterial function to understanding phosphatase activity. Future work will broaden the diversity of tree species and microbial members sampled to provide insight into P mineralization and model representation of tropical forests.
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Affiliation(s)
- Kristine G. Cabugao
- Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN, United States
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Collin M. Timm
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Alyssa A. Carrell
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Joanne Childs
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Tse-Yuan S. Lu
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Dale A. Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - David J. Weston
- Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Richard J. Norby
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, United States
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22
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Henning JA, Weston DJ, Pelletier DA, Timm CM, Jawdy SS, Classen AT. Root bacterial endophytes alter plant phenotype, but not physiology. PeerJ 2016; 4:e2606. [PMID: 27833797 PMCID: PMC5101591 DOI: 10.7717/peerj.2606] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/24/2016] [Indexed: 12/15/2022] Open
Abstract
Plant traits, such as root and leaf area, influence how plants interact with their environment and the diverse microbiota living within plants can influence plant morphology and physiology. Here, we explored how three bacterial strains isolated from the Populus root microbiome, influenced plant phenotype. We chose three bacterial strains that differed in predicted metabolic capabilities, plant hormone production and metabolism, and secondary metabolite synthesis. We inoculated each bacterial strain on a single genotype of Populus trichocarpa and measured the response of plant growth related traits (root:shoot, biomass production, root and leaf growth rates) and physiological traits (chlorophyll content, net photosynthesis, net photosynthesis at saturating light-Asat, and saturating CO2-Amax). Overall, we found that bacterial root endophyte infection increased root growth rate up to 184% and leaf growth rate up to 137% relative to non-inoculated control plants, evidence that plants respond to bacteria by modifying morphology. However, endophyte inoculation had no influence on total plant biomass and photosynthetic traits (net photosynthesis, chlorophyll content). In sum, bacterial inoculation did not significantly increase plant carbon fixation and biomass, but their presence altered where and how carbon was being allocated in the plant host.
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Affiliation(s)
- Jeremiah A. Henning
- Department of Ecology & Evolutionary Biology, University of Tennessee–Knoxville, Knoxville, Tennessee, United States
| | - David J. Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Dale A. Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Collin M. Timm
- Joint Institute for Biological Sciences, University of Tennessee, Oak Ridge, TN, United States
| | - Sara S. Jawdy
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Aimée T. Classen
- Department of Ecology & Evolutionary Biology, University of Tennessee–Knoxville, Knoxville, Tennessee, United States
- Center for Macroecology, Evolution, and Climate, The Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
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23
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Utturkar SM, Cude WN, Robeson MS, Yang ZK, Klingeman DM, Land ML, Allman SL, Lu TYS, Brown SD, Schadt CW, Podar M, Doktycz MJ, Pelletier DA. Enrichment of Root Endophytic Bacteria from Populus deltoides and Single-Cell-Genomics Analysis. Appl Environ Microbiol 2016; 82:5698-708. [PMID: 27422831 PMCID: PMC5007785 DOI: 10.1128/aem.01285-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/07/2016] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Bacterial endophytes that colonize Populus trees contribute to nutrient acquisition, prime immunity responses, and directly or indirectly increase both above- and below-ground biomasses. Endophytes are embedded within plant material, so physical separation and isolation are difficult tasks. Application of culture-independent methods, such as metagenome or bacterial transcriptome sequencing, has been limited due to the predominance of DNA from the plant biomass. Here, we describe a modified differential and density gradient centrifugation-based protocol for the separation of endophytic bacteria from Populus roots. This protocol achieved substantial reduction in contaminating plant DNA, allowed enrichment of endophytic bacteria away from the plant material, and enabled single-cell genomics analysis. Four single-cell genomes were selected for whole-genome amplification based on their rarity in the microbiome (potentially uncultured taxa) as well as their inferred abilities to form associations with plants. Bioinformatics analyses, including assembly, contamination removal, and completeness estimation, were performed to obtain single-amplified genomes (SAGs) of organisms from the phyla Armatimonadetes, Verrucomicrobia, and Planctomycetes, which were unrepresented in our previous cultivation efforts. Comparative genomic analysis revealed unique characteristics of each SAG that could facilitate future cultivation efforts for these bacteria. IMPORTANCE Plant roots harbor a diverse collection of microbes that live within host tissues. To gain a comprehensive understanding of microbial adaptations to this endophytic lifestyle from strains that cannot be cultivated, it is necessary to separate bacterial cells from the predominance of plant tissue. This study provides a valuable approach for the separation and isolation of endophytic bacteria from plant root tissue. Isolated live bacteria provide material for microbiome sequencing, single-cell genomics, and analyses of genomes of uncultured bacteria to provide genomics information that will facilitate future cultivation attempts.
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Affiliation(s)
- Sagar M Utturkar
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee, USA
| | - W Nathan Cude
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Michael S Robeson
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Zamin K Yang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Dawn M Klingeman
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Miriam L Land
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Steve L Allman
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Tse-Yuan S Lu
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Steven D Brown
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | | | - Mircea Podar
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Mitchel J Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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24
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Hansen RR, Timm AC, Timm CM, Bible AN, Morrell-Falvey JL, Pelletier DA, Simpson ML, Doktycz MJ, Retterer ST. Correction: Stochastic Assembly of Bacteria in Microwell Arrays Reveals the Importance of Confinement in Community Development. PLoS One 2016; 11:e0160135. [PMID: 27441627 PMCID: PMC4956270 DOI: 10.1371/journal.pone.0160135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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25
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Manga P, Klingeman DM, Lu TYS, Mehlhorn TL, Pelletier DA, Hauser LJ, Wilson CM, Brown SD. Replicates, Read Numbers, and Other Important Experimental Design Considerations for Microbial RNA-seq Identified Using Bacillus thuringiensis Datasets. Front Microbiol 2016; 7:794. [PMID: 27303383 PMCID: PMC4886094 DOI: 10.3389/fmicb.2016.00794] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 05/11/2016] [Indexed: 11/13/2022] Open
Abstract
RNA-seq is being used increasingly for gene expression studies and it is revolutionizing the fields of genomics and transcriptomics. However, the field of RNA-seq analysis is still evolving. Therefore, we specifically designed this study to contain large numbers of reads and four biological replicates per condition so we could alter these parameters and assess their impact on differential expression results. Bacillus thuringiensis strains ATCC10792 and CT43 were grown in two Luria broth medium lots on four dates and transcriptomics data were generated using one lane of sequence output from an Illumina HiSeq2000 instrument for each of the 32 samples, which were then analyzed using DESeq2. Genome coverages across samples ranged from 87 to 465X with medium lots and culture dates identified as major variation sources. Significantly differentially expressed genes (5% FDR, two-fold change) were detected for cultures grown using different medium lots and between different dates. The highly differentially expressed iron acquisition and metabolism genes, were a likely consequence of differing amounts of iron in the two media lots. Indeed, in this study RNA-seq was a tool for predictive biology since we hypothesized and confirmed the two LB medium lots had different iron contents (~two-fold difference). This study shows that the noise in data can be controlled and minimized with appropriate experimental design and by having the appropriate number of replicates and reads for the system being studied. We outline parameters for an efficient and cost effective microbial transcriptomics study.
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Affiliation(s)
- Punita Manga
- Graduate School of Genome Science and Technology, University of TennesseeKnoxville, TN, USA; BioEnergy Science Center, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Dawn M Klingeman
- BioEnergy Science Center, Oak Ridge National LaboratoryOak Ridge, TN, USA; Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Tse-Yuan S Lu
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Tonia L Mehlhorn
- Environmental Sciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Dale A Pelletier
- Graduate School of Genome Science and Technology, University of TennesseeKnoxville, TN, USA; Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Loren J Hauser
- Graduate School of Genome Science and Technology, University of TennesseeKnoxville, TN, USA; Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Charlotte M Wilson
- BioEnergy Science Center, Oak Ridge National LaboratoryOak Ridge, TN, USA; Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Steven D Brown
- Graduate School of Genome Science and Technology, University of TennesseeKnoxville, TN, USA; BioEnergy Science Center, Oak Ridge National LaboratoryOak Ridge, TN, USA; Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
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26
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Hansen RH, Timm AC, Timm CM, Bible AN, Morrell-Falvey JL, Pelletier DA, Simpson ML, Doktycz MJ, Retterer ST. Stochastic Assembly of Bacteria in Microwell Arrays Reveals the Importance of Confinement in Community Development. PLoS One 2016; 11:e0155080. [PMID: 27152511 PMCID: PMC4859483 DOI: 10.1371/journal.pone.0155080] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/24/2016] [Indexed: 12/26/2022] Open
Abstract
The structure and function of microbial communities is deeply influenced by the physical and chemical architecture of the local microenvironment and the abundance of its community members. The complexity of this natural parameter space has made characterization of the key drivers of community development difficult. In order to facilitate these characterizations, we have developed a microwell platform designed to screen microbial growth and interactions across a wide variety of physical and initial conditions. Assembly of microbial communities into microwells was achieved using a novel biofabrication method that exploits well feature sizes for control of innoculum levels. Wells with incrementally smaller size features created populations with increasingly larger variations in inoculum levels. This allowed for reproducible growth measurement in large (20 μm diameter) wells, and screening for favorable growth conditions in small (5, 10 μm diameter) wells. We demonstrate the utility of this approach for screening and discovery using 5 μm wells to assemble P. aeruginosa colonies across a broad distribution of innoculum levels, and identify those conditions that promote the highest probability of survivial and growth under spatial confinement. Multi-member community assembly was also characterized to demonstrate the broad potential of this platform for studying the role of member abundance on microbial competition, mutualism and community succession.
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Affiliation(s)
- Ryan H Hansen
- Kansas State University, Manhattan, Kansas, United States of America.,The University of Tennessee, Knoxville, Tennessee, United States of America
| | - Andrea C Timm
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Collin M Timm
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Amber N Bible
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Jennifer L Morrell-Falvey
- The University of Tennessee, Knoxville, Tennessee, United States of America.,Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Dale A Pelletier
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Michael L Simpson
- The University of Tennessee, Knoxville, Tennessee, United States of America.,Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Mitchel J Doktycz
- The University of Tennessee, Knoxville, Tennessee, United States of America.,Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Scott T Retterer
- The University of Tennessee, Knoxville, Tennessee, United States of America.,Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
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27
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Bible AN, Fletcher SJ, Pelletier DA, Schadt CW, Jawdy SS, Weston DJ, Engle NL, Tschaplinski T, Masyuko R, Polisetti S, Bohn PW, Coutinho TA, Doktycz MJ, Morrell-Falvey JL. A Carotenoid-Deficient Mutant in Pantoea sp. YR343, a Bacteria Isolated from the Rhizosphere of Populus deltoides, Is Defective in Root Colonization. Front Microbiol 2016; 7:491. [PMID: 27148182 PMCID: PMC4834302 DOI: 10.3389/fmicb.2016.00491] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/24/2016] [Indexed: 11/13/2022] Open
Abstract
The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. A better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically important plants. Pantoea sp. YR343 is a motile, rod-shaped bacterium isolated from the roots of Populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone indole-3-acetic acid (IAA). Pantoea sp. YR343 readily colonizes plant roots and does not appear to be pathogenic when applied to the leaves or roots of selected plant hosts. To better understand the molecular mechanisms involved in plant association and rhizosphere survival by Pantoea sp. YR343, we constructed a mutant in which the crtB gene encoding phytoene synthase was deleted. Phytoene synthase is responsible for converting geranylgeranyl pyrophosphate to phytoene, an important precursor to the production of carotenoids. As predicted, the ΔcrtB mutant is defective in carotenoid production, and shows increased sensitivity to oxidative stress. Moreover, we find that the ΔcrtB mutant is impaired in biofilm formation and production of IAA. Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots. Taken together, these data suggest that carotenoids are important for plant association and/or rhizosphere survival in Pantoea sp. YR343.
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Affiliation(s)
- Amber N. Bible
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Sarah J. Fletcher
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Dale A. Pelletier
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | | | - Sara S. Jawdy
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - David J. Weston
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Nancy L. Engle
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | | | - Rachel Masyuko
- Department of Chemical and Biomolecular Engineering, University of Notre DameNotre Dame, IN, USA
| | - Sneha Polisetti
- Department of Chemical and Biomolecular Engineering, University of Notre DameNotre Dame, IN, USA
| | - Paul W. Bohn
- Department of Chemical and Biomolecular Engineering, University of Notre DameNotre Dame, IN, USA
| | - Teresa A. Coutinho
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute, University of PretoriaPretoria, South Africa
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28
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Timm CM, Pelletier DA, Jawdy SS, Gunter LE, Henning JA, Engle N, Aufrecht J, Gee E, Nookaew I, Yang Z, Lu TY, Tschaplinski TJ, Doktycz MJ, Tuskan GA, Weston DJ. Two Poplar-Associated Bacterial Isolates Induce Additive Favorable Responses in a Constructed Plant-Microbiome System. Front Plant Sci 2016; 7:497. [PMID: 27200001 PMCID: PMC4845692 DOI: 10.3389/fpls.2016.00497] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 03/29/2016] [Indexed: 05/18/2023]
Abstract
The biological function of the plant-microbiome system is the result of contributions from the host plant and microbiome members. The Populus root microbiome is a diverse community that has high abundance of β- and γ-Proteobacteria, both classes which include multiple plant-growth promoting representatives. To understand the contribution of individual microbiome members in a community, we studied the function of a simplified community consisting of Pseudomonas and Burkholderia bacterial strains isolated from Populus hosts and inoculated on axenic Populus cutting in controlled laboratory conditions. Both strains increased lateral root formation and root hair production in Arabidopsis plate assays and are predicted to encode for different functions related to growth and plant growth promotion in Populus hosts. Inoculation individually, with either bacterial isolate, increased root growth relative to uninoculated controls, and while root area was increased in mixed inoculation, the interaction term was insignificant indicating additive effects of root phenotype. Complementary data including photosynthetic efficiency, whole-transcriptome gene expression and GC-MS metabolite expression data in individual and mixed inoculated treatments indicate that the effects of these bacterial strains are unique and additive. These results suggest that the function of a microbiome community may be predicted from the additive functions of the individual members.
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Affiliation(s)
- Collin M. Timm
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
- *Correspondence: Collin M. Timm
| | - Dale A. Pelletier
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Sara S. Jawdy
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Lee E. Gunter
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Jeremiah A. Henning
- Department of Ecology and Evolutionary Biology, University of TennesseeKnoxville, TN, USA
| | - Nancy Engle
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Jayde Aufrecht
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
- Bredesen Center for Interdisciplinary Research and Graduate Education, University of TennesseeKnoxville, TN, USA
| | - Emily Gee
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Intawat Nookaew
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Zamin Yang
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Tse-Yuan Lu
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | | | | | - Gerald A. Tuskan
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - David J. Weston
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
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29
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Timm CM, Hansen RR, Doktycz MJ, Retterer ST, Pelletier DA. Microstencils to generate defined, multi-species patterns of bacteria. Biomicrofluidics 2015; 9:064103. [PMID: 26594264 PMCID: PMC4644145 DOI: 10.1063/1.4935938] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/05/2015] [Indexed: 05/21/2023]
Abstract
Microbial communities are complex heterogeneous systems that are influenced by physical and chemical interactions with their environment, host, and community members. Techniques that facilitate the quantitative evaluation of how microscale organization influences the morphogenesis of multispecies communities could provide valuable insights into the dynamic behavior and organization of natural communities, the design of synthetic environments for multispecies culture, and the engineering of artificial consortia. In this work, we demonstrate a method for patterning microbes into simple arrangements that allow the quantitative measurement of growth dynamics as a function of their proximity to one another. The method combines parylene-based liftoff techniques with microfluidic delivery to simultaneously pattern multiple bacterial species with high viability using low-cost, customizable methods. Quantitative measurements of bacterial growth for two competing isolates demonstrate that spatial coordination can play a critical role in multispecies growth and structure.
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Affiliation(s)
- Collin M Timm
- Biosciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, USA
| | - Ryan R Hansen
- Department of Chemical Engineering, Kansas State University , Manhattan, Kansas 66506, USA
| | | | | | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, USA
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Timm CM, Campbell AG, Utturkar SM, Jun SR, Parales RE, Tan WA, Robeson MS, Lu TYS, Jawdy S, Brown SD, Ussery DW, Schadt CW, Tuskan GA, Doktycz MJ, Weston DJ, Pelletier DA. Metabolic functions of Pseudomonas fluorescens strains from Populus deltoides depend on rhizosphere or endosphere isolation compartment. Front Microbiol 2015; 6:1118. [PMID: 26528266 PMCID: PMC4604316 DOI: 10.3389/fmicb.2015.01118] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 09/28/2015] [Indexed: 12/13/2022] Open
Abstract
The bacterial microbiota of plants is diverse, with 1000s of operational taxonomic units (OTUs) associated with any individual plant. In this work, we used phenotypic analysis, comparative genomics, and metabolic models to investigate the differences between 19 sequenced Pseudomonas fluorescens strains. These isolates represent a single OTU and were collected from the rhizosphere and endosphere of Populus deltoides. While no traits were exclusive to either endosphere or rhizosphere P. fluorescens isolates, multiple pathways relevant for plant-bacterial interactions are enriched in endosphere isolate genomes. Further, growth phenotypes such as phosphate solubilization, protease activity, denitrification and root growth promotion are biased toward endosphere isolates. Endosphere isolates have significantly more metabolic pathways for plant signaling compounds and an increased metabolic range that includes utilization of energy rich nucleotides and sugars, consistent with endosphere colonization. Rhizosphere P. fluorescens have fewer pathways representative of plant-bacterial interactions but show metabolic bias toward chemical substrates often found in root exudates. This work reveals the diverse functions that may contribute to colonization of the endosphere by bacteria and are enriched among closely related isolates.
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Affiliation(s)
- Collin M Timm
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Alisha G Campbell
- Department of Natural Sciences, Northwest Missouri State University Maryville, MO, USA
| | - Sagar M Utturkar
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA ; Graduate School of Genome Science and Technology, University of Tennessee, Knoxville Knoxville, TN, USA
| | - Se-Ran Jun
- Joint Institute for Computational Sciences, University of Tennessee, Knoxville Knoxville, TN, USA
| | - Rebecca E Parales
- Microbiology and Molecular Genetics, University of California, Davis Davis, CA, USA
| | - Watumesa A Tan
- Microbiology and Molecular Genetics, University of California, Davis Davis, CA, USA
| | - Michael S Robeson
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA ; Fish, Wildlife and Conservation Biology, Colorado State University Fort Collins, CO, USA
| | - Tse-Yuan S Lu
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Sara Jawdy
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Steven D Brown
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA ; Graduate School of Genome Science and Technology, University of Tennessee, Knoxville Knoxville, TN, USA
| | - David W Ussery
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Christopher W Schadt
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA ; Department of Microbiology, University of Tennessee, Knoxville Knoxville, TN, USA
| | - Gerald A Tuskan
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Mitchel J Doktycz
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
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Allen MS, Hurst GB, Lu TYS, Perry LM, Pan C, Lankford PK, Pelletier DA. Rhodopseudomonas palustris CGA010 Proteome Implicates Extracytoplasmic Function Sigma Factor in Stress Response. J Proteome Res 2015; 14:2158-68. [PMID: 25853567 DOI: 10.1021/pr5012558] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rhodopseudomonas palustris encodes 16 extracytoplasmic function (ECF) σ factors. To begin to investigate the regulatory network of one of these ECF σ factors, the whole proteome of R. palustris CGA010 was quantitatively analyzed by tandem mass spectrometry from cultures episomally expressing the ECF σ(RPA4225) (ecfT) versus a WT control. Among the proteins with the greatest increase in abundance were catalase KatE, trehalose synthase, a DPS-like protein, and several regulatory proteins. Alignment of the cognate promoter regions driving expression of several upregulated proteins suggested a conserved binding motif in the -35 and -10 regions with the consensus sequence GGAAC-18N-TT. Additionally, the putative anti-σ factor RPA4224, whose gene is contained in the same predicted operon as RPA4225, was identified as interacting directly with the predicted response regulator RPA4223 by mass spectrometry of affinity-isolated protein complexes. Furthermore, another gene (RPA4226) coding for a protein that contains a cytoplasmic histidine kinase domain is located immediately upstream of RPA4225. The genomic organization of orthologs for these four genes is conserved in several other strains of R. palustris as well as in closely related α-Proteobacteria. Taken together, these data suggest that ECF σ(RPA4225) and the three additional genes make up a sigma factor mimicry system in R. palustris.
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Affiliation(s)
- Michael S Allen
- §Department of Biological Sciences, University of North Texas, Denton, Texas 76203-5017, United States.,∥Center for Biosafety and Biosecurity Department of Molecular and Medical Genetics, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | | | | | - Leslie M Perry
- §Department of Biological Sciences, University of North Texas, Denton, Texas 76203-5017, United States
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Labbé JL, Weston DJ, Dunkirk N, Pelletier DA, Tuskan GA. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus. Front Plant Sci 2014; 5:579. [PMID: 25386184 PMCID: PMC4208408 DOI: 10.3389/fpls.2014.00579] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 10/08/2014] [Indexed: 05/24/2023]
Abstract
Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two additional Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were included for comparative purposes. We analyzed the effect of co-cultivation of these 23 individual Pseudomonas strains on Laccaria bicolor "S238N" growth rate, mycelial architecture and transcriptional changes. Nineteen of the 23 Pseudomonas strains tested had positive effects on L. bicolor S238N growth, as well as on mycelial architecture, with strains GM41 and GM18 having the most significant effect. Four of seven L. bicolor reporter genes, Tra1, Tectonin2, Gcn5, and Cipc1, thought to be regulated during the interaction with MHB strain BBc6R8, were induced or repressed, while interacting with Pseudomonas strains GM17, GM33, GM41, GM48, Pf-5, and BBc6R8. Strain GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve L. bicolor root colonization on Populus. This tripartite relationship could be exploited for Populus species/genotypes nursery production as a means of improving establishment and survival in marginal lands.
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Affiliation(s)
- Jessy L. Labbé
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
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Utturkar SM, Klingeman DM, Land ML, Schadt CW, Doktycz MJ, Pelletier DA, Brown SD. Evaluation and validation of de novo and hybrid assembly techniques to derive high-quality genome sequences. ACTA ACUST UNITED AC 2014; 30:2709-16. [PMID: 24930142 PMCID: PMC4173024 DOI: 10.1093/bioinformatics/btu391] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
MOTIVATION To assess the potential of different types of sequence data combined with de novo and hybrid assembly approaches to improve existing draft genome sequences. RESULTS Illumina, 454 and PacBio sequencing technologies were used to generate de novo and hybrid genome assemblies for four different bacteria, which were assessed for quality using summary statistics (e.g. number of contigs, N50) and in silico evaluation tools. Differences in predictions of multiple copies of rDNA operons for each respective bacterium were evaluated by PCR and Sanger sequencing, and then the validated results were applied as an additional criterion to rank assemblies. In general, assemblies using longer PacBio reads were better able to resolve repetitive regions. In this study, the combination of Illumina and PacBio sequence data assembled through the ALLPATHS-LG algorithm gave the best summary statistics and most accurate rDNA operon number predictions. This study will aid others looking to improve existing draft genome assemblies. AVAILABILITY AND IMPLEMENTATION All assembly tools except CLC Genomics Workbench are freely available under GNU General Public License. CONTACT brownsd@ornl.gov SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Sagar M Utturkar
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Dawn M Klingeman
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Miriam L Land
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Christopher W Schadt
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Mitchel J Doktycz
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Dale A Pelletier
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Steven D Brown
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37919, USA and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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Ovchinnikova OS, Kjoller K, Hurst GB, Pelletier DA, Van Berkel GJ. Atomic force microscope controlled topographical imaging and proximal probe thermal desorption/ionization mass spectrometry imaging. Anal Chem 2013; 86:1083-90. [PMID: 24377265 DOI: 10.1021/ac4026576] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This paper reports on the development of a hybrid atmospheric pressure atomic force microscopy/mass spectrometry imaging system utilizing nanothermal analysis probes for thermal desorption surface sampling with subsequent atmospheric pressure chemical ionization and mass analysis. The basic instrumental setup and the general operation of the system were discussed, and optimized performance metrics were presented. The ability to correlate topographic images of a surface with atomic force microscopy and a mass spectral chemical image of the same surface, utilizing the same probe without moving the sample from the system, was demonstrated. Co-registered mass spectral chemical images and atomic force microscopy topographical images were obtained from inked patterns on paper as well as from a living bacterial colony on an agar gel. Spatial resolution of the topography images based on pixel size (0.2 μm × 0.8 μm) was better than the resolution of the mass spectral images (2.5 μm × 2.0 μm), which were limited by current mass spectral data acquisition rate and system detection levels.
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Affiliation(s)
- Olga S Ovchinnikova
- Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831-6131
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Hansen RR, Hinestrosa JP, Shubert KR, Morrell-Falvey JL, Pelletier DA, Messman JM, Kilbey SM, Lokitz BS, Retterer ST. Lectin-functionalized poly(glycidyl methacrylate)-block-poly(vinyldimethyl azlactone) surface scaffolds for high avidity microbial capture. Biomacromolecules 2013; 14:3742-8. [PMID: 24003861 DOI: 10.1021/bm4011358] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microbial exopolysaccharides (EPS) play a critical and dynamic role in shaping the interactions between microbial community members and their local environment. The capture of targeted microbes using surface immobilized lectins that recognize specific extracellular oligosaccharide moieties offers a nondestructive method for functional characterization of EPS content. In this report, we evaluate the use of the block copolymer, poly(glycidyl methacrylate)-block-4,4-dimethyl-2-vinylazlactone (PGMA-b-PVDMA), as a surface scaffold for lectin-specific microbial capture. Three-dimensional polymer films were patterned on silicon substrates to provide discrete, covalent coupling sites for Triticum vulgare and Lens culinaris lectins. This material increased the number of Pseudomonas fluorescens microbes captured by up to 43% compared to control scaffolds that did not contain the copolymer. These results demonstrate that PGMA-b-PVDMA scaffolds provide a platform for improved microbe capture and screening of EPS content by combining high avidity lectin surfaces with three-dimensional surface topography.
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Affiliation(s)
- Ryan R Hansen
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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Abstract
Metal and metal oxide nanoparticles are among the most commonly used nanomaterials and their potential for adversely affecting environmental systems raises concern. Complex microbial consortia underlie environmental processes, and the potential toxicity of nanoparticles to microbial systems, and the consequent impacts on trophic balances, is particularly worrisome. The diverse array of metal and metal oxides, the different sizes and shapes that can be prepared and the variety of possible surface coatings complicate assessments of toxicity. Further muddling biocidal interpretations are the diversity of microbes and their intrinsic tolerances to stresses. Here, we review a range of studies focused on nanoparticle-microbial interactions in an effort to correlate the physical-chemical properties of engineered metal and metal oxide nanoparticles to their biological response. General conclusions regarding the parent material of the nanoparticle and the nanoparticle's size and shape on potential toxicity can be made. However, the surface coating of the material, which can be altered significantly by environmental conditions, can ameliorate or promote microbial toxicity. Understanding nanoparticle transformations and how the nanoparticle surface can be designed to control toxicity represents a key area for further study. Additionally, the vast array of microbial species and the structuring of these species within communities complicate extrapolations of nanoparticle toxicity in real world settings. Ultimately, to interpret the effect and eventual fate of engineered materials in the environment, an understanding of the relationship between nanoparticle properties and responses at the molecular, cellular and community levels will be essential.
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Affiliation(s)
- Anil K Suresh
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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Weston DJ, Pelletier DA, Morrell-Falvey JL, Tschaplinski TJ, Jawdy SS, Lu TY, Allen SM, Melton SJ, Martin MZ, Schadt CW, Karve AA, Chen JG, Yang X, Doktycz MJ, Tuskan GA. Pseudomonas fluorescens induces strain-dependent and strain-independent host plant responses in defense networks, primary metabolism, photosynthesis, and fitness. Mol Plant Microbe Interact 2012; 25:765-78. [PMID: 22375709 DOI: 10.1094/mpmi-09-11-0253] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Colonization of plants by nonpathogenic Pseudomonas fluorescens strains can confer enhanced defense capacity against a broad spectrum of pathogens. Few studies, however, have linked defense pathway regulation to primary metabolism and physiology. In this study, physiological data, metabolites, and transcript profiles are integrated to elucidate how molecular networks initiated at the root-microbe interface influence shoot metabolism and whole-plant performance. Experiments with Arabidopsis thaliana were performed using the newly identified P. fluorescens GM30 or P. fluorescens Pf-5 strains. Co-expression networks indicated that Pf-5 and GM30 induced a subnetwork specific to roots enriched for genes participating in RNA regulation, protein degradation, and hormonal metabolism. In contrast, only GM30 induced a subnetwork enriched for calcium signaling, sugar and nutrient signaling, and auxin metabolism, suggesting strain dependence in network architecture. In addition, one subnetwork present in shoots was enriched for genes in secondary metabolism, photosynthetic light reactions, and hormone metabolism. Metabolite analysis indicated that this network initiated changes in carbohydrate and amino acid metabolism. Consistent with this, we observed strain-specific responses in tryptophan and phenylalanine abundance. Both strains reduced host plant carbon gain and fitness, yet provided a clear fitness benefit when plants were challenged with the pathogen P. syringae DC3000.
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Affiliation(s)
- David J Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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Crosby HA, Pelletier DA, Hurst GB, Escalante-Semerena JC. System-wide studies of N-lysine acetylation in Rhodopseudomonas palustris reveal substrate specificity of protein acetyltransferases. J Biol Chem 2012; 287:15590-601. [PMID: 22416131 DOI: 10.1074/jbc.m112.352104] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
N-lysine acetylation is a posttranslational modification that has been well studied in eukaryotes and is likely widespread in prokaryotes as well. The central metabolic enzyme acetyl-CoA synthetase is regulated in both bacteria and eukaryotes by acetylation of a conserved lysine residue in the active site. In the purple photosynthetic α-proteobacterium Rhodopseudomonas palustris, two protein acetyltransferases (RpPat and the newly identified RpKatA) and two deacetylases (RpLdaA and RpSrtN) regulate the activities of AMP-forming acyl-CoA synthetases. In this work, we used LC/MS/MS to identify other proteins regulated by the N-lysine acetylation/deacetylation system of this bacterium. Of the 24 putative acetylated proteins identified, 14 were identified more often in a strain lacking both deacetylases. Nine of these proteins were members of the AMP-forming acyl-CoA synthetase family. RpPat acetylated all nine of the acyl-CoA synthetases identified by this work, and RpLdaA deacetylated eight of them. In all cases, acetylation occurred at the conserved lysine residue in the active site, and acetylation decreased activity of the enzymes by >70%. Our results show that many different AMP-forming acyl-CoA synthetases are regulated by N-lysine acetylation. Five non-acyl-CoA synthetases were identified as possibly acetylated, including glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and Rpa1177, a putative 4-oxalocrotonate tautomerase. Neither RpPat nor RpKatA acetylated either of these proteins in vitro. It has been reported that Salmonella enterica Pat (SePat) can acetylate a number of metabolic enzymes, including GAPDH, but we were unable to confirm this claim, suggesting that the substrate range of SePat is not as broad as suggested previously.
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Affiliation(s)
- Heidi A Crosby
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Suresh AK, Pelletier DA, Wang W, Morrell-Falvey JL, Gu B, Doktycz MJ. Cytotoxicity induced by engineered silver nanocrystallites is dependent on surface coatings and cell types. Langmuir 2012; 28:2727-2735. [PMID: 22216981 DOI: 10.1021/la2042058] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Due to their unique antimicrobial properties silver nanocrystallites have garnered substantial attention and are used extensively for biomedical applications as an additive to wound dressings, surgical instruments and bone substitute materials. They are also released into unintended locations such as the environment or biosphere. Therefore it is imperative to understand the potential interactions, fate and transport of nanoparticles with environmental biotic systems. Numerous factors including the composition, size, shape, surface charge, and capping molecule of nanoparticles are known to influence cell cytotoxicity. Our results demonstrate that the physical/chemical properties of the silver nanoparticles including surface charge, differential binding and aggregation potential, which are influenced by the surface coatings, are a major determining factor in eliciting cytotoxicity and in dictating potential cellular interactions. In the present investigation, silver nanocrystallites with nearly uniform size and shape distribution but with different surface coatings, imparting overall high negativity to high positivity, were synthesized. These nanoparticles included poly(diallyldimethylammonium) chloride-Ag, biogenic-Ag, colloidal-Ag (uncoated), and oleate-Ag with zeta potentials +45 ± 5, -12 ± 2, -42 ± 5, and -45 ± 5 mV, respectively; the particles were purified and thoroughly characterized so as to avoid false cytotoxicity interpretations. A systematic investigation on the cytotoxic effects, cellular response, and membrane damage caused by these four different silver nanoparticles was carried out using multiple toxicity measurements on mouse macrophage (RAW-264.7) and lung epithelial (C-10) cell lines. Our results clearly indicate that the cytotoxicity was dependent on various factors such as surface charge and coating materials used in the synthesis, particle aggregation, and the cell-type for the different silver nanoparticles that were investigated. Poly(diallyldimethylammonium)-coated Ag nanoparticles were found to be the most toxic, followed by biogenic-Ag and oleate-Ag nanoparticles, whereas uncoated or colloidal silver nanoparticles were found to be the least toxic to both macrophage and lung epithelial cells. Also, based on our cytotoxicity interpretations, lung epithelial cells were found to be more resistant to the silver nanoparticles than the macrophage cells, regardless of the surface coating.
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Affiliation(s)
- Anil K Suresh
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831 United States.
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Suresh AK, Doktycz MJ, Wang W, Moon JW, Gu B, Meyer HM, Hensley DK, Allison DP, Phelps TJ, Pelletier DA. Monodispersed biocompatible silver sulfide nanoparticles: facile extracellular biosynthesis using the γ-proteobacterium, Shewanella oneidensis. Acta Biomater 2011; 7:4253-8. [PMID: 21798382 DOI: 10.1016/j.actbio.2011.07.007] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 06/30/2011] [Accepted: 07/08/2011] [Indexed: 10/18/2022]
Abstract
Interest in engineered metal and semiconductor nanocrystallites continues to grow due to their unique size- and shape-dependent optoelectronic, physicochemical and biological properties. Therefore identifying novel non-hazardous nanoparticle synthesis routes that address hydrophilicity, size and shape control and production costs has become a priority. In the present article we report for the first time on the efficient generation of extracellular silver sulfide (Ag₂S) nanoparticles by the metal-reducing bacterium Shewanella oneidensis. The particles are reasonably monodispersed and homogeneously shaped. They are produced under ambient temperatures and pressures at high yield, 85% theoretical maximum. UV-visible and Fourier transform infrared spectroscopy, dynamic light scattering, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy measurements confirmed the formation, optical and surface properties, purity and crystallinity of the synthesized particles. Further characterization revealed that the particles consist of spheres with a mean diameter of 9±3.5 nm, and are capped by a detachable protein/peptide surface coat. Toxicity assessments of these biogenic Ag₂S nanoparticles on Gram-negative (Escherichia coli and S. oneidensis) and Gram-positive (Bacillus subtilis) bacterial systems, as well as eukaryotic cell lines including mouse lung epithelial (C 10) and macrophage (RAW-264.7) cells, showed that the particles were non-inhibitory and non-cytotoxic to any of these systems. Our results provide a facile, eco-friendly and economical route for the fabrication of technologically important semiconducting Ag₂S nanoparticles. These particles are dispersible and biocompatible, thus providing excellent potential for use in optical imaging, electronic devices and solar cell applications.
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Suresh AK, Pelletier DA, Wang W, Broich ML, Moon JW, Gu B, Allison DP, Joy DC, Phelps TJ, Doktycz MJ. Biofabrication of discrete spherical gold nanoparticles using the metal-reducing bacterium Shewanella oneidensis. Acta Biomater 2011; 7:2148-52. [PMID: 21241833 DOI: 10.1016/j.actbio.2011.01.023] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 12/08/2010] [Accepted: 01/13/2011] [Indexed: 10/18/2022]
Abstract
Nanocrystallites have garnered substantial interest due to their various applications, including catalysis and medical research. Consequently important aspects of synthesis related to control of shape and size through economical and non-hazardous means are desirable. Highly efficient bioreduction-based fabrication approaches that utilize microbes and/or plant extracts are poised to meet these needs. Here we show that the γ-proteobacterium Shewanella oneidensis can reduce tetrachloroaurate (III) ions to produce discrete extracellular spherical gold nanocrystallites. The particles were homogeneously shaped with multiple size distributions and produced under ambient conditions at high yield, 88% theoretical maximum. Further characterization revealed that the particles consist of spheres in the size range of ∼2-50 nm, with an average size of 12±5 nm. The nanoparticles were hydrophilic and resisted aggregation even after several months. Based on our experiments, the particles are likely fabricated by the aid of reducing agents present in the bacterial cell membrane and are capped by a detachable protein/peptide coat. Ultraviolet-visible and Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray spectra and transmission electron microscopy measurements confirmed the formation, surface characteristics and crystalline nature of the nanoparticles. The antibacterial activity of these gold nanoparticles was assessed using Gram-negative (Escherichia coli and S. oneidensis) and Gram-positive (Bacillus subtilis) bacterial species. Toxicity assessments showed that the particles were neither toxic nor inhibitory to any of these bacteria.
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Pelletier DA, Suresh AK, Holton GA, McKeown CK, Wang W, Gu B, Mortensen NP, Allison DP, Joy DC, Allison MR, Brown SD, Phelps TJ, Doktycz MJ. Effects of engineered cerium oxide nanoparticles on bacterial growth and viability. Appl Environ Microbiol 2010; 76:7981-9. [PMID: 20952651 PMCID: PMC3008265 DOI: 10.1128/aem.00650-10] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 10/05/2010] [Indexed: 11/20/2022] Open
Abstract
Interest in engineered nanostructures has risen in recent years due to their use in energy conservation strategies and biomedicine. To ensure prudent development and use of nanomaterials, the fate and effects of such engineered structures on the environment should be understood. Interactions of nanomaterials with environmental microorganisms are inevitable, but the general consequences of such interactions remain unclear, due to a lack of standard methods for assessing such interactions. Therefore, we have initiated a multianalytical approach to understand the interactions of synthesized nanoparticles with bacterial systems. These efforts are focused initially on cerium oxide nanoparticles and model bacteria in order to evaluate characterization procedures and the possible fate of such materials in the environment. The growth and viability of the Gram-negative species Escherichia coli and Shewanella oneidensis, a metal-reducing bacterium, and the Gram-positive species Bacillus subtilis were examined relative to cerium oxide particle size, growth media, pH, and dosage. A hydrothermal synthesis approach was used to prepare cerium oxide nanoparticles of defined sizes in order to eliminate complications originating from the use of organic solvents and surfactants. Bactericidal effects were determined from MIC and CFU measurements, disk diffusion tests, and live/dead assays. For E. coli and B. subtilis, clear strain- and size-dependent inhibition was observed, whereas S. oneidensis appeared to be unaffected by the particles. Transmission electron microscopy along with microarray-based transcriptional profiling was used to understand the response mechanism of the bacteria. Use of multiple analytical approaches adds confidence to toxicity assessments, while the use of different bacterial systems highlights the potential wide-ranging effects of nanomaterial interactions in the environment.
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Affiliation(s)
- Dale A. Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Anil K. Suresh
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Gregory A. Holton
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Catherine K. McKeown
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Wei Wang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Baohua Gu
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Ninell P. Mortensen
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - David P. Allison
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - David C. Joy
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Martin R. Allison
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Steven D. Brown
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Tommy J. Phelps
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
| | - Mitchel J. Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6422, Department of Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6488
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Suresh AK, Pelletier DA, Wang W, Moon JW, Gu B, Mortensen NP, Allison DP, Joy DC, Phelps TJ, Doktycz MJ. Silver nanocrystallites: biofabrication using Shewanella oneidensis, and an evaluation of their comparative toxicity on gram-negative and gram-positive bacteria. Environ Sci Technol 2010; 44:5210-5. [PMID: 20509652 DOI: 10.1021/es903684r] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Microorganisms have long been known to develop resistance to metal ions either by sequestering metals inside the cell or by effluxing them into the extracellular media. Here we report the biosynthesis of extracellular silver-based single nanocrystallites of well-defined composition and homogeneous morphology utilizing the gamma-proteobacterium, Shewanella oneidensis MR-1, upon incubation with aqueous silver nitrate solution. Further characterization of these particles revealed that the crystals consist of small, reasonably monodispersed spheres in the 2-11 nm size range (average of 4 +/- 1.5 nm). The bactericidal effect of these nanoparticles (biogenic-Ag) is compared to chemically synthesized silver nanoparticles (colloidal-Ag and oleate capped silver nanoparticles, oleate-Ag) and assessed using Gram-negative (E. coli and S. oneidensis) and Gram-positive (B. subtilis) bacteria. Relative toxicity was based on the diameter of inhibition zone in disk diffusion tests, minimum inhibitory concentrations, live/dead assays, and atomic force microscopy. From a toxicity perspective, strain-dependent inhibition depended on the synthesis procedure and the surface coat. Biogenic-Ag was found to be of higher toxicity compared to colloidal-Ag for all three strains tested, whereas E. coli and S. oneidensis were found to be more resistant to either of these nanoparticles than B. subtilis. In contrast, oleate-Ag was not toxic to any of the bacteria. These findings have implications for the potential uses of Ag nanomaterials and for their fate in biological and environmental systems.
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Affiliation(s)
- Anil K Suresh
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831-6445, USA.
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Yang S, Pelletier DA, Lu TYS, Brown SD. The Zymomonas mobilis regulator hfq contributes to tolerance against multiple lignocellulosic pretreatment inhibitors. BMC Microbiol 2010; 10:135. [PMID: 20459639 PMCID: PMC2877685 DOI: 10.1186/1471-2180-10-135] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 05/07/2010] [Indexed: 11/29/2022] Open
Abstract
Background Zymomonas mobilis produces near theoretical yields of ethanol and recombinant strains are candidate industrial microorganisms. To date, few studies have examined its responses to various stresses at the gene level. Hfq is a conserved bacterial member of the Sm-like family of RNA-binding proteins, coordinating a broad array of responses including multiple stress responses. In a previous study, we observed Z. mobilis ZM4 gene ZMO0347 showed higher expression under anaerobic, stationary phase compared to that of aerobic, stationary conditions. Results We generated a Z. mobilis hfq insertion mutant AcRIM0347 in an acetate tolerant strain (AcR) background and investigated its role in model lignocellulosic pretreatment inhibitors including acetate, vanillin, furfural and hydroxymethylfurfural (HMF). Saccharomyces cerevisiae Lsm protein (Hfq homologue) mutants and Lsm protein overexpression strains were also assayed for their inhibitor phenotypes. Our results indicated that all the pretreatment inhibitors tested in this study had a detrimental effect on both Z. mobilis and S. cerevisiae, and vanillin had the most inhibitory effect followed by furfural and then HMF for both Z. mobilis and S. cerevisiae. AcRIM0347 was more sensitive than the parental strain to the inhibitors and had an increased lag phase duration and/or slower growth depending upon the conditions. The hfq mutation in AcRIM0347 was complemented partially by trans-acting hfq gene expression. We also assayed growth phenotypes for S. cerevisiae Lsm protein mutant and overexpression phenotypes. Lsm1, 6, and 7 mutants showed reduced tolerance to acetate and other pretreatment inhibitors. S. cerevisiae Lsm protein overexpression strains showed increased acetate and HMF resistance as compared to the wild-type, while the overexpression strains showed greater inhibition under vanillin stress conditions. Conclusions We have shown the utility of the pKNOCK suicide plasmid for mutant construction in Z. mobilis, and constructed a Gateway compatible expression plasmid for use in Z. mobilis for the first time. We have also used genetics to show Z. mobilis Hfq and S. cerevisiae Lsm proteins play important roles in resisting multiple, important industrially relevant inhibitors. The conserved nature of this global regulator offers the potential to apply insights from these fundamental studies for further industrial strain development.
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Affiliation(s)
- Shihui Yang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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Taylor RC, Singhal M, Daly DS, Gilmore J, Cannon WR, Domico K, White AM, Auberry DL, Auberry KJ, Hooker BS, Hurst G, McDermott JE, McDonald WH, Pelletier DA, Schmoyer D, Wiley HS. An analysis pipeline for the inference of protein-protein interaction networks. INT J DATA MIN BIOIN 2010; 3:409-30. [PMID: 20052905 DOI: 10.1504/ijdmb.2009.029204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a platform for the reconstruction of protein-protein interaction networks inferred from Mass Spectrometry (MS) bait-prey data. The Software Environment for Biological Network Inference (SEBINI), an environment for the deployment of network inference algorithms that use high-throughput data, forms the platform core. Among the many algorithms available in SEBINI is the Bayesian Estimator of Probabilities of Protein-Protein Associations (BEPro3) algorithm, which is used to infer interaction networks from such MS affinity isolation data. Also, the pipeline incorporates the Collective Analysis of Biological Interaction Networks (CABIN) software. We have thus created a structured workflow for protein-protein network inference and supplemental analysis.
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Affiliation(s)
- Ronald C Taylor
- Computational Sciences and Mathematics Division, Pacific Northwest National Laboratory (US Department of Energy), Richland, WA 99352, USA.
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Abstract
Understanding the molecular pathways of plant cell wall biosynthesis and remodeling is central to interpreting biological mechanisms underlying plant growth and adaptation as well as leveraging that knowledge towards development of improved bioenergy feedstocks. Here, we report the application of shotgun MS/MS profiling to the proteome of Populus developing xylem. Nearly 6000 different proteins were identified from the xylem proteome. To identify low-abundance DNA-regulatory proteins from the developing xylem, a selective nuclear proteome profiling method was developed. Several putative transcription factors and chromatin remodeling proteins were identified using this method, such as NAC domain, CtCP-like and CHB3-SWI/SNF-related proteins. Public databases were mined to obtain information in support of subcellular localization, transcript-level expression and functional categorization of identified proteins. In addition to finding protein-level evidence of candidate cell wall biosynthesis genes from xylem (wood) tissue such as cellulose synthase, sucrose synthase and polygalacturonase, several other potentially new candidate genes in the cell wall biosynthesis pathway were discovered. Further application of such proteomics methods will aid in plant systems biology modeling efforts by enhancing the understanding not only of cell wall biosynthesis but also of other plant developmental and physiological pathways.
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Affiliation(s)
- Udaya C Kalluri
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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47
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Edwards AN, Fowlkes JD, Owens ET, Standaert RF, Pelletier DA, Hurst GB, Doktycz MJ, Morrell-Falvey JL. An in vivo imaging-based assay for detecting protein interactions over a wide range of binding affinities. Anal Biochem 2009; 395:166-77. [PMID: 19698693 DOI: 10.1016/j.ab.2009.08.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 08/13/2009] [Accepted: 08/17/2009] [Indexed: 11/28/2022]
Abstract
Identifying and characterizing protein interactions are fundamental steps toward understanding and modeling biological networks. Methods that detect protein interactions in intact cells rather than buffered solutions are likely more relevant to natural systems since molecular crowding events in the cytosol can influence the diffusion and reactivity of individual proteins. One in vivo, imaging-based method relies on the colocalization of two proteins of interest fused to DivIVA, a cell division protein from Bacillus subtilis, and green fluorescent protein (GFP). We have modified this imaging-based assay to facilitate rapid cloning by constructing new vectors encoding N- and C-terminal DivIVA or GFP molecular tag fusions based on site-specific recombination technology. The sensitivity of the assay was defined using a well-characterized protein interaction system involving the eukaryotic nuclear import receptor subunit, Importin alpha (Imp alpha), and variant nuclear localization signals (NLS) representing a range of binding affinities. These data demonstrate that the modified colocalization assay is sensitive enough to detect protein interactions with K(d) values that span over four orders of magnitude (1 nM to 15 microM). Lastly, this assay was used to confirm numerous protein interactions identified from mass spectrometry-based analyses of affinity isolates as part of an interactome mapping project in Rhodopseudomonas palustris.
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Affiliation(s)
- A Nicole Edwards
- University of Tennessee-Oak Ridge National Laboratory, Graduate School of Genome Science and Technology, Knoxville, TN 37996, USA
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Hervey WJ, Khalsa-Moyers G, Lankford PK, Owens ET, McKeown CK, Lu TY, Foote LJ, Asano KG, Morrell-Falvey JL, McDonald WH, Pelletier DA, Hurst GB. Evaluation of Affinity-Tagged Protein Expression Strategies Using Local and Global Isotope Ratio Measurements. J Proteome Res 2009; 8:3675-88. [DOI: 10.1021/pr801088f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- W. Judson Hervey
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Gurusahai Khalsa-Moyers
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Patricia K. Lankford
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Elizabeth T. Owens
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Catherine K. McKeown
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Tse-Yuan Lu
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Linda J. Foote
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Keiji G. Asano
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Jennifer L. Morrell-Falvey
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - W. Hayes McDonald
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Dale A. Pelletier
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
| | - Gregory B. Hurst
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville and Oak Ridge National Laboratory, 1060 Commerce Park Drive, Oak Ridge, Tennessee 37830-8026, Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, and Biosciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6131
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Karpinets TV, Pelletier DA, Pan C, Uberbacher EC, Melnichenko GV, Hettich RL, Samatova NF. Phenotype fingerprinting suggests the involvement of single-genotype consortia in degradation of aromatic compounds by Rhodopseudomonas palustris. PLoS One 2009; 4:e4615. [PMID: 19242537 PMCID: PMC2643473 DOI: 10.1371/journal.pone.0004615] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Accepted: 01/07/2009] [Indexed: 11/18/2022] Open
Abstract
Anaerobic degradation of complex organic compounds by microorganisms is crucial for development of innovative biotechnologies for bioethanol production and for efficient degradation of environmental pollutants. In natural environments, the degradation is usually accomplished by syntrophic consortia comprised of different bacterial species. This strategy allows consortium organisms to reduce efforts required for maintenance of the redox homeostasis at each syntrophic level. Cellular mechanisms that maintain the redox homeostasis during the degradation of aromatic compounds by one organism are not fully understood. Here we present a hypothesis that the metabolically versatile phototrophic bacterium Rhodopseudomonas palustris forms its own syntrophic consortia, when it grows anaerobically on p-coumarate or benzoate as a sole carbon source. We have revealed the consortia from large-scale measurements of mRNA and protein expressions under p-coumarate, benzoate and succinate degrading conditions using a novel computational approach referred as phenotype fingerprinting. In this approach, marker genes for known R. palustris phenotypes are employed to determine the relative expression levels of genes and proteins in aromatics versus non-aromatics degrading condition. Subpopulations of the consortia are inferred from the expression of phenotypes and known metabolic modes of the R. palustris growth. We find that p-coumarate degrading conditions may lead to at least three R. palustris subpopulations utilizing p-coumarate, benzoate, and CO2 and H2. Benzoate degrading conditions may also produce at least three subpopulations utilizing benzoate, CO2 and H2, and N2 and formate. Communication among syntrophs and inter-syntrophic dynamics in each consortium are indicated by up-regulation of transporters and genes involved in the curli formation and chemotaxis. The N2-fixing subpopulation in the benzoate degrading consortium has preferential activation of the vanadium nitrogenase over the molybdenum nitrogenase. This subpopulation in the consortium was confirmed in an independent experiment by consumption of dissolved nitrogen gas under the benzoate degrading conditions.
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Affiliation(s)
- Tatiana V Karpinets
- Computational Biology Institute, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
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50
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Parales RE, Parales JV, Pelletier DA, Ditty JL. Diversity of microbial toluene degradation pathways. Adv Appl Microbiol 2008; 64:1-73, 2 p following 264. [PMID: 18485280 DOI: 10.1016/s0065-2164(08)00401-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- R E Parales
- Department of Microbiology, University of California, Davis, California 95616, USA
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