1
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Wagner MR. Identifying causes and consequences of rhizosphere microbiome heritability. PLoS Biol 2024; 22:e3002604. [PMID: 38669216 PMCID: PMC11051602 DOI: 10.1371/journal.pbio.3002604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024] Open
Abstract
Host genotype affects microbiome composition in many plants, but the mechanisms and implications of this phenomenon are understudied. New work in PLOS Biology illustrates how host genotype leads to differential gene expression and fitness in bacteria of the barley rhizosphere.
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Affiliation(s)
- Maggie R. Wagner
- Department of Ecology & Evolutionary Biology; Kansas Biological Survey & Center for Ecological Research; University of Kansas, Lawrence, Kansas, United States of America
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2
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Parnell JJ, Vintila S, Tang C, Wagner MR, Kleiner M. Evaluation of ready-to-use freezer stocks of a synthetic microbial community for maize root colonization. Microbiol Spectr 2024; 12:e0240123. [PMID: 38084978 PMCID: PMC10783020 DOI: 10.1128/spectrum.02401-23] [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: 06/07/2023] [Accepted: 11/06/2023] [Indexed: 01/13/2024] Open
Abstract
IMPORTANCE Synthetic communities (SynComs) are an invaluable tool to characterize and model plant-microbe interactions. Multimember SynComs approximate intricate real-world interactions between plants and their microbiome, but the complexity and time required for their construction increase enormously for each additional member added to the SynCom. Therefore, researchers who study a diversity of microbiomes using SynComs are looking for ways to simplify the use of SynComs. In this manuscript, we evaluate the feasibility of creating ready-to-use freezer stocks of a well-studied seven-member SynCom for maize roots. The frozen ready-to-use SynCom stocks work according to the principle of "just add buffer and apply to sterilized seeds or seedlings" and thus can save time applied in multiple days of laborious growing and combining of multiple microorganisms. We show that ready-to-use SynCom stocks provide comparable results to those of freshly constructed SynComs and thus allow for significant time savings when working with SynComs.
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Affiliation(s)
- J. Jacob Parnell
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
| | - Simina Vintila
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
| | - Clara Tang
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
| | - Maggie R. Wagner
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA
- Kansas Biological Survey & Center for Ecological Research, University of Kansas, Lawrence, Kansas, USA
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
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3
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Kural-Rendon C, Ford NE, Wagner MR. Interactions with fungi vary among Tripsacum dactyloides genotypes from across a precipitation gradient. AoB Plants 2023; 15:plad072. [PMID: 38028745 PMCID: PMC10667659 DOI: 10.1093/aobpla/plad072] [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] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 11/01/2023] [Indexed: 12/01/2023]
Abstract
Plant-associated microbes, specifically fungal endophytes, augment the ability of many grasses to adapt to extreme environmental conditions. Tripsacum dactyloides (Eastern gamagrass) is a perennial, drought-tolerant grass native to the tallgrass prairies of the central USA. The extent to which the microbiome of T. dactyloides contributes to its drought tolerance is unknown. Ninety-seven genotypes of T. dactyloides were collected from native populations across an east-west precipitation gradient in Kansas, Oklahoma and Texas, and then grown together in a common garden for over 20 years. Root and leaf samples were visually examined for fungal density. Because fungal endophytes confer drought-tolerant capabilities to their host plants, we expected to find higher densities of fungal endophytes in plants from western, drier regions, compared to plants from eastern, wetter regions. Results confirmed a negative correlation between endophyte densities in roots and precipitation at the genotype's original location (r = -0.21 P = 0.04). Our analyses reveal that the host genotype's origin along the precipitation gradient predicts the absolute abundance of symbionts in the root, but not the relative abundances of particular organisms or the overall community composition. Overall, these results demonstrate that genetic variation for plant-microbe interactions can reflect historical environment, and reinforce the importance of considering plant genotype in conservation and restoration work in tallgrass prairie ecosystems.
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Affiliation(s)
- Ceyda Kural-Rendon
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA
| | - Natalie E Ford
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA
- Kansas Biological Survey and Center for Ecological Research, University of Kansas, Lawrence, KS 66045, USA
| | - Maggie R Wagner
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA
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4
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Wagner MR, Mitchell-Olds T. Soil variation among natural habitats alters glucosinolate content in a wild perennial mustard. J Exp Bot 2023; 74:1723-1740. [PMID: 36583734 PMCID: PMC10010606 DOI: 10.1093/jxb/erac520] [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: 08/16/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Baseline levels of glucosinolates-important defensive phytochemicals in brassicaceous plants-are determined by both genotype and environment. However, the ecological causes of glucosinolate plasticity are not well characterized. Fertilization is known to alter glucosinolate content of Brassica crops, but the effect of naturally occurring soil variation on glucosinolate content of wild plants is unknown. Here, we conducted greenhouse experiments using Boechera stricta to ask (i) whether soil variation among natural habitats shapes leaf and root glucosinolate profiles; (ii) whether such changes are caused by abiotic soil properties, soil microbes, or both; and (iii) whether soil-induced glucosinolate plasticity is genetically variable. Total glucosinolate quantity differed up to 2-fold between soils from different natural habitats, while the relative amounts of different compounds were less responsive. This effect was due to physico-chemical soil properties rather than microbial communities. We detected modest genetic variation for glucosinolate plasticity in response to soil. In addition, glucosinolate composition, but not quantity, of field-grown plants could be accurately predicted from measurements from greenhouse-grown plants. In summary, soil alone is sufficient to cause plasticity of baseline glucosinolate levels in natural plant populations, which may have implications for the evolution of this important trait across complex landscapes.
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Affiliation(s)
- Maggie R Wagner
- Department of Ecology and Evolutionary Biology, Kansas Biological Survey and Center for Ecological Research, University of Kansas, Lawrence, KS 66045, USA
| | - Thomas Mitchell-Olds
- Program in Genetics and Genomics, Department of Biology, Duke University, Durham, NC 27708, USA
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5
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Rushworth CA, Wagner MR, Mitchell-Olds T, Anderson JT. The Boechera model system for evolutionary ecology. Am J Bot 2022; 109:1939-1961. [PMID: 36371714 DOI: 10.1002/ajb2.16090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 08/27/2022] [Accepted: 08/30/2022] [Indexed: 06/16/2023]
Abstract
Model systems in biology expand the research capacity of individuals and the community. Closely related to Arabidopsis, the genus Boechera has emerged as an important ecological model owing to the ability to integrate across molecular, functional, and eco-evolutionary approaches. Boechera species are broadly distributed in relatively undisturbed habitats predominantly in western North America and provide one of the few experimental systems for identification of ecologically important genes through genome-wide association studies and investigations of selection with plants in their native habitats. The ecologically, evolutionarily, and agriculturally important trait of apomixis (asexual reproduction via seeds) is common in the genus, and field experiments suggest that abiotic and biotic environments shape the evolution of sex. To date, population genetic studies have focused on the widespread species B. stricta, detailing population divergence and demographic history. Molecular and ecological studies show that balancing selection maintains genetic variation in ~10% of the genome, and ecological trade-offs contribute to complex trait variation for herbivore resistance, flowering phenology, and drought tolerance. Microbiome analyses have shown that host genotypes influence leaf and root microbiome composition, and the soil microbiome influences flowering phenology and natural selection. Furthermore, Boechera offers numerous opportunities for investigating biological responses to global change. In B. stricta, climate change has induced a shift of >2 weeks in the timing of first flowering since the 1970s, altered patterns of natural selection, generated maladaptation in previously locally-adapted populations, and disrupted life history trade-offs. Here we review resources and results for this eco-evolutionary model system and discuss future research directions.
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Affiliation(s)
| | - Maggie R Wagner
- Department of Ecology and Evolutionary Biology, Kansas Biological Survey and Center for Ecological Research, University of Kansas, Lawrence, KS, 66045, USA
| | | | - Jill T Anderson
- Department of Genetics and Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA
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6
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Abstract
Maize genes influence which species of bacteria are recruited from the soil, especially in the absence of nitrogen supplied by fertilizer.
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Affiliation(s)
- Maggie R Wagner
- Department of Ecology and Evolutionary Biology, Kansas Biological Survey and Center for Ecological Research, University of Kansas
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7
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O'Brien AM, Ginnan NA, Rebolleda-Gómez M, Wagner MR. Microbial effects on plant phenology and fitness. Am J Bot 2021; 108:1824-1837. [PMID: 34655479 DOI: 10.1002/ajb2.1743] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 07/07/2021] [Indexed: 06/13/2023]
Abstract
Plant development and the timing of developmental events (phenology) are tightly coupled with plant fitness. A variety of internal and external factors determine the timing and fitness consequences of these life-history transitions. Microbes interact with plants throughout their life history and impact host phenology. This review summarizes current mechanistic and theoretical knowledge surrounding microbe-driven changes in plant phenology. Overall, there are examples of microbes impacting every phenological transition. While most studies have focused on flowering time, microbial effects remain important for host survival and fitness across all phenological phases. Microbe-mediated changes in nutrient acquisition and phytohormone signaling can release plants from stressful conditions and alter plant stress responses inducing shifts in developmental events. The frequency and direction of phenological effects appear to be partly determined by the lifestyle and the underlying nature of a plant-microbe interaction (i.e., mutualistic or pathogenic), in addition to the taxonomic group of the microbe (fungi vs. bacteria). Finally, we highlight biases, gaps in knowledge, and future directions. This biotic source of plasticity for plant adaptation will serve an important role in sustaining plant biodiversity and managing agriculture under the pressures of climate change.
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Affiliation(s)
- Anna M O'Brien
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Nichole A Ginnan
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA
| | - María Rebolleda-Gómez
- Department of Ecology and Evolutionary Biology, University of California-Irvine, Irvine, CA, USA
| | - Maggie R Wagner
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA
- Kansas Biological Survey and Center for Ecological Research, University of Kansas, Lawrence, KS, USA
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8
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Wagner MR. Prioritizing host phenotype to understand microbiome heritability in plants. New Phytol 2021; 232:502-509. [PMID: 34287929 DOI: 10.1111/nph.17622] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/02/2021] [Indexed: 05/06/2023]
Abstract
Breeders and evolutionary geneticists have grappled with the complexity of the 'genotype-to-phenotype map' for decades. Now, recent studies highlight the relevance of this concept for understanding heritability of plant microbiomes. Because host phenotype is a more proximate cause of microbiome variation than host genotype, microbiome heritability varies across plant anatomy and development. Fine-scale variation of plant traits within organs suggests that the well-established concept of 'microbiome compartment' should be refined. Additionally, recent work shows that the balance of deterministic processes (including host genetic effects) vs stochastic processes also varies over time and space. Together, these findings suggest that re-centering plant phenotype - both as a predictor and a readout of microbiome function - will accelerate new insights into microbiome heritability.
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Affiliation(s)
- Maggie R Wagner
- Department of Ecology and Evolutionary Biology, Kansas Biological Survey, University of Kansas, Lawrence, KS, 66045, USA
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Clouse KM, Wagner MR. Plant Genetics as a Tool for Manipulating Crop Microbiomes: Opportunities and Challenges. Front Bioeng Biotechnol 2021; 9:567548. [PMID: 34136470 PMCID: PMC8201784 DOI: 10.3389/fbioe.2021.567548] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 05/05/2021] [Indexed: 11/22/2022] Open
Abstract
Growing human population size and the ongoing climate crisis create an urgent need for new tools for sustainable agriculture. Because microbiomes have profound effects on host health, interest in methods of manipulating agricultural microbiomes is growing rapidly. Currently, the most common method of microbiome manipulation is inoculation of beneficial organisms or engineered communities; however, these methods have been met with limited success due to the difficulty of establishment in complex farm environments. Here we propose genetic manipulation of the host plant as another avenue through which microbiomes could be manipulated. We discuss how domestication and modern breeding have shaped crop microbiomes, as well as the potential for improving plant-microbiome interactions through conventional breeding or genetic engineering. We summarize the current state of knowledge on host genetic control of plant microbiomes, as well as the key challenges that remain.
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Affiliation(s)
- Kayla M. Clouse
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, United States
| | - Maggie R. Wagner
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, United States
- Kansas Biological Survey, University of Kansas, Lawrence, KS, United States
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Delavaux CS, Sturmer SL, Wagner MR, Schütte U, Morton JB, Bever JD. Utility of large subunit for environmental sequencing of arbuscular mycorrhizal fungi: a new reference database and pipeline. New Phytol 2021; 229:3048-3052. [PMID: 33190292 DOI: 10.1111/nph.17080] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Affiliation(s)
- Camille S Delavaux
- Department of Ecology and Evolutionary Biology, The University of Kansas, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
- Kansas Biological Survey, The University of Kansas, 106 Higuchi Hall, 2101 Constant Ave, Lawrence, KS, 66047, USA
| | - Sidney L Sturmer
- Departamento de Ciências Naturais, Universidade Regional de Blumenau, R. Antônio da Veiga 140, Blumenau, Santa Catarina, 89030-903, Brazil
| | - Maggie R Wagner
- Department of Ecology and Evolutionary Biology, The University of Kansas, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
- Kansas Biological Survey, The University of Kansas, 106 Higuchi Hall, 2101 Constant Ave, Lawrence, KS, 66047, USA
| | - Ursel Schütte
- Institute of Arctic Biology, University of Alaska Fairbanks, 2140 Koyukuk Drive, Fairbanks, AK, 99775, USA
| | - Joseph B Morton
- West Virginia University, 6 Alegre Pass, Santa Fe, Morgantown, NM, 87508, USA
| | - James D Bever
- Department of Ecology and Evolutionary Biology, The University of Kansas, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
- Kansas Biological Survey, The University of Kansas, 106 Higuchi Hall, 2101 Constant Ave, Lawrence, KS, 66047, USA
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11
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Wagner MR, Roberts JH, Balint-Kurti P, Holland JB. Heterosis of leaf and rhizosphere microbiomes in field-grown maize. New Phytol 2020; 228:1055-1069. [PMID: 32521050 DOI: 10.1111/nph.16730] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 05/28/2020] [Indexed: 05/21/2023]
Abstract
Macroorganisms' genotypes shape their phenotypes, which in turn shape the habitat available to potential microbial symbionts. This influence of host genotype on microbiome composition has been demonstrated in many systems; however, most previous studies have either compared unrelated genotypes or delved into molecular mechanisms. As a result, it is currently unclear whether the heritability of host-associated microbiomes follows similar patterns to the heritability of other complex traits. We take a new approach to this question by comparing the microbiomes of diverse maize inbred lines and their F1 hybrid offspring, which we quantified in both rhizosphere and leaves of field-grown plants using 16S-v4 and ITS1 amplicon sequencing. We show that inbred lines and hybrids differ consistently in the composition of bacterial and fungal rhizosphere communities, as well as leaf-associated fungal communities. A wide range of microbiome features display heterosis within individual crosses, consistent with patterns for nonmicrobial maize phenotypes. For leaf microbiomes, these results were supported by the observation that broad-sense heritability in hybrids was substantially higher than narrow-sense heritability. Our results support our hypothesis that at least some heterotic host traits affect microbiome composition in maize.
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Affiliation(s)
- Maggie R Wagner
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
- Kansas Biological Survey, University of Kansas, Lawrence, KS, 66045, USA
| | - Joseph H Roberts
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Peter Balint-Kurti
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
- Plant Science Research Unit, Agricultural Research Service, United States Department of Agriculture, Raleigh, NC, 27695, USA
| | - James B Holland
- Plant Science Research Unit, Agricultural Research Service, United States Department of Agriculture, Raleigh, NC, 27695, USA
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC, 27695, USA
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12
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Persson R, Lee S, Yood MU, Wagner MR, Minton N, Niemcryk S, Lindholm A, Evans AM, Jick S. Incident depression in patients diagnosed with multiple sclerosis: a multi-database study. Eur J Neurol 2020; 27:1556-1560. [PMID: 32397001 DOI: 10.1111/ene.14314] [Citation(s) in RCA: 8] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/26/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND PURPOSE Data on rates of newly diagnosed depression after multiple sclerosis (MS) diagnosis are sparse. Here, incident, treated depression in MS patients after diagnosis compared with matched non-MS patients is described. METHODS A matched cohort study was conducted in two separate electronic medical databases: the US Department of Defense (US-DOD) military healthcare system and the UK's Clinical Practice Research Datalink GOLD (UK-CPRD). The study population included all patients with a first recorded diagnosis of MS and matched non-MS patients. Patients with a history of treated depression were excluded. Incidence rates and incidence rate ratios with 95% confidence intervals for treated depression after MS diagnosis/matched date were estimated. RESULTS Incidence rate ratios of treated depression amongst MS patients compared with non-MS patients were 3.20 (95% confidence interval 3.05-3.35) in the US-DOD and 1.90 (95% confidence interval 1.74-2.06) in the UK-CPRD. Incidence rate ratios were elevated across age and sex. Rates were higher in females than males but, compared to non-MS patients, males with MS had a higher relative risk than females with MS. CONCLUSIONS Multiple sclerosis patients in the UK and the USA have a two- to three-fold increased risk of new, treated depression compared to matched non-MS patients.
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Affiliation(s)
- R Persson
- Epidemiology, Boston Collaborative Drug Surveillance Program, Lexington, MA, USA
| | - S Lee
- Drug Safety, Celgene Corporation, Summit, NJ, USA
| | - M U Yood
- Chief Scientific Officer, EpiSource LLC, Newton, MA, USA.,Boston University School of Public Health, Boston, MA, USA
| | - M R Wagner
- Department of Neurology, Naval Medical Center Portsmouth, Portsmouth, VA, USA
| | - N Minton
- Drug Safety, Celgene Corporation, Summit, NJ, USA
| | - S Niemcryk
- Drug Safety, Celgene Corporation, Summit, NJ, USA
| | - A Lindholm
- Drug Safety, Celgene Corporation, Summit, NJ, USA
| | - A M Evans
- Epidemiology, Health ResearchTx LLC, Trevose, PA, USA
| | - S Jick
- Epidemiology, Boston Collaborative Drug Surveillance Program, Lexington, MA, USA.,Boston University School of Public Health, Boston, MA, USA
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13
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Wagner MR, Busby PE, Balint-Kurti P. Analysis of leaf microbiome composition of near-isogenic maize lines differing in broad-spectrum disease resistance. New Phytol 2020; 225:2152-2165. [PMID: 31657460 DOI: 10.1111/nph.16284] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 10/18/2019] [Indexed: 06/10/2023]
Abstract
Plant genotype strongly affects disease resistance, and also influences the composition of the leaf microbiome. However, these processes have not been studied and linked in the microevolutionary context of breeding for improved disease resistance. We hypothesised that broad-spectrum disease resistance alleles also affect colonisation by nonpathogenic symbionts. Quantitative trait loci (QTL) conferring resistance to multiple fungal pathogens were introgressed into a disease-susceptible maize inbred line. Bacterial and fungal leaf microbiomes of the resulting near-isogenic lines were compared with the microbiome of the disease-susceptible parent line at two time points in multiple fields. Introgression of QTL from disease-resistant lines strongly shifted the relative abundance of diverse fungal and bacterial taxa in both 3-wk-old and 7-wk-old plants. Nevertheless, the effects on overall community structure and diversity were minor and varied among fields and years. Contrary to our expectations, host genotype effects were not any stronger in fields with high disease pressure than in uninfected fields, and microbiome succession over time was similar in heavily infected and uninfected plants. These results show that introgressed QTL can greatly improve broad-spectrum disease resistance while having only limited and inconsistent pleiotropic effects on the leaf microbiome in maize.
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Affiliation(s)
- Maggie R Wagner
- Department of Ecology and Evolutionary Biology, Kansas Biological Survey, University of Kansas, Lawrence, KS, 66047, USA
| | - Posy E Busby
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Peter Balint-Kurti
- Plant Science Research Unit, Agricultural Research Service, United States Department of Agriculture, Raleigh, NC, 27695, USA
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
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14
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Abstract
Phenotypic plasticity is thought to impact evolutionary trajectories by shifting trait values in a direction that is either favored by natural selection ("adaptive" plasticity) or disfavored ("nonadaptive" plasticity). However, it is unclear how commonly each of these types of plasticity occurs in natural populations. To answer this question, we measured glucosinolate defensive chemistry and reproductive fitness in over 1500 individuals of the wild perennial mustard Boechera stricta, planted in four common gardens across central Idaho, United States. Glucosinolate profiles-including total glucosinolate concentration as well as the relative abundances and overall diversity of different compounds-were strongly plastic both among habitats and within habitats. Patterns of glucosinolate plasticity varied greatly among genotypes. Plasticity among sites was predicted to affect fitness in 27.1% of cases; more often than expected by chance, glucosinolate plasticity increased rather than decreased relative fitness. In contrast, we found no evidence for within-habitat selection on glucosinolate reaction norm slopes (i.e., plasticity along a continuous environmental gradient). Together, our results indicate that glucosinolate plasticity may improve the ability of B. stricta populations to persist after migration to new habitats.
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Affiliation(s)
- Maggie R Wagner
- Program in Genetics and Genomics, Department of Biology, Duke University, Durham, North Carolina 27708.,Current Address: Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695
| | - Thomas Mitchell-Olds
- Program in Genetics and Genomics, Department of Biology, Duke University, Durham, North Carolina 27708
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15
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Geml J, Wagner MR. Out of sight, but no longer out of mind - towards an increased recognition of the role of soil microbes in plant speciation. New Phytol 2018; 217:965-967. [PMID: 29334601 DOI: 10.1111/nph.14979] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Affiliation(s)
- József Geml
- Biodiversity Dynamics Research Group, Naturalis Biodiversity Center, PO Box 9517, 2300 RA, Leiden, the Netherlands
| | - Maggie R Wagner
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA
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16
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Sachat AE, Reparaz JS, Spiece J, Alonso MI, Goñi AR, Garriga M, Vaccaro PO, Wagner MR, Kolosov OV, Sotomayor Torres CM, Alzina F. Thermal transport in epitaxial Si 1-x Ge x alloy nanowires with varying composition and morphology. Nanotechnology 2017; 28:505704. [PMID: 29160238 DOI: 10.1088/1361-6528/aa9497] [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] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report on structural, compositional, and thermal characterization of self-assembled in-plane epitaxial Si1-x Ge x alloy nanowires grown by molecular beam epitaxy on Si (001) substrates. The thermal properties were studied by means of scanning thermal microscopy (SThM), while the microstructural characteristics, the spatial distribution of the elemental composition of the alloy nanowires and the sample surface were investigated by transmission electron microscopy and energy dispersive x-ray microanalysis. We provide new insights regarding the morphology of the in-plane nanostructures, their size-dependent gradient chemical composition, and the formation of a 5 nm thick wetting layer on the Si substrate surface. In addition, we directly probe heat transfer between a heated scanning probe sensor and Si1-x Ge x alloy nanowires of different morphological characteristics and we quantify their thermal resistance variations. We correlate the variations of the thermal signal to the dependence of the heat spreading with the cross-sectional geometry of the nanowires using finite element method simulations. With this method we determine the thermal conductivity of the nanowires with values in the range of 2-3 W m-1 K-1. These results provide valuable information in growth processes and show the great capability of the SThM technique in ambient environment for nanoscale thermal studies, otherwise not possible using conventional techniques.
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Affiliation(s)
- A El Sachat
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, E-08193 Barcelona, Spain. Department of Physics, Universitat Autònoma de Barcelona, Campus UAB, E-08193 Bellaterra (Barcelona), Spain
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Busby PE, Soman C, Wagner MR, Friesen ML, Kremer J, Bennett A, Morsy M, Eisen JA, Leach JE, Dangl JL. Research priorities for harnessing plant microbiomes in sustainable agriculture. PLoS Biol 2017; 15:e2001793. [PMID: 28350798 PMCID: PMC5370116 DOI: 10.1371/journal.pbio.2001793] [Citation(s) in RCA: 336] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Feeding a growing world population amidst climate change requires optimizing the reliability, resource use, and environmental impacts of food production. One way to assist in achieving these goals is to integrate beneficial plant microbiomes-i.e., those enhancing plant growth, nutrient use efficiency, abiotic stress tolerance, and disease resistance-into agricultural production. This integration will require a large-scale effort among academic researchers, industry researchers, and farmers to understand and manage plant-microbiome interactions in the context of modern agricultural systems. Here, we identify priorities for research in this area: (1) develop model host-microbiome systems for crop plants and non-crop plants with associated microbial culture collections and reference genomes, (2) define core microbiomes and metagenomes in these model systems, (3) elucidate the rules of synthetic, functionally programmable microbiome assembly, (4) determine functional mechanisms of plant-microbiome interactions, and (5) characterize and refine plant genotype-by-environment-by-microbiome-by-management interactions. Meeting these goals should accelerate our ability to design and implement effective agricultural microbiome manipulations and management strategies, which, in turn, will pay dividends for both the consumers and producers of the world food supply.
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Affiliation(s)
- Posy E. Busby
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Chinmay Soman
- Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana Champaign, Urbana, Illinois, United States of America
| | - Maggie R. Wagner
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Maren L. Friesen
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, United States of America
- Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, Michigan, United States of America
| | - James Kremer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
| | - Alison Bennett
- The James Hutton Institute, Invergowrie, Dundee, Scotland
| | - Mustafa Morsy
- College of Natural Sciences and Mathematics, University of West Alabama, Livingston, Alabama, United States of America
| | - Jonathan A. Eisen
- Genome Center, University of California, Davis, California, United States of America
| | - Jan E. Leach
- Bioagricultural Sciences and Pest Management, Colorado State University, Ft Collins, Colorado, United States of America
| | - Jeffery L. Dangl
- Howard Hughes Medical Institute, Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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D'Amato AW, Orwig DA, Foster DR, Barker Plotkin A, Schoonmaker PK, Wagner MR. Long-term structural and biomass dynamics of virgin Tsuga canadensis-Pinus strobus forests after hurricane disturbance. Ecology 2016; 98:721-733. [PMID: 27984662 DOI: 10.1002/ecy.1684] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 10/19/2016] [Accepted: 11/29/2016] [Indexed: 11/06/2022]
Abstract
The development of old-growth forests in northeastern North America has largely been within the context of gap-scale disturbances given the rarity of stand-replacing disturbances. Using the 10-ha old-growth Harvard Tract and its associated 90-year history of measurements, including detailed surveys in 1989 and 2009, we document the long-term structural and biomass development of an old-growth Tsuga canadensis-Pinus strobus forest in southern New Hampshire, USA following a stand-replacing hurricane in 1938. Measurements of aboveground biomass pools were integrated with data from second- and old-growth T. canadensis forests to evaluate long-term patterns in biomass development following this disturbance. Ecosystem structure across the Tract prior to the hurricane exhibited a high degree of spatial heterogeneity with the greatest levels of live tree basal area (70-129 m2 /ha) on upper west-facing slopes where P. strobus was dominant and intermixed with T. canadensis. Live-tree biomass estimates for these stratified mixtures ranged from 159 to 503 Mg/ha at the localized, plot scale (100 m2 ) and averaged 367 Mg/ha across these portions of the landscape approaching the upper bounds for eastern forests. Live-tree biomass 71 years after the hurricane is more uniform and lower in magnitude, with T. canadensis currently the dominant overstory tree species throughout much of the landscape. Despite only one living P. strobus stem in the 2009 plots (and fewer than five stems known across the entire 10-ha area), the detrital legacy of this species is pronounced with localized accumulations of coarse woody debris exceeding 237.7-404.2 m3 /ha where this species once dominated the canopy. These patterns underscore the great sizes P. strobus attained in pre-European landscapes and its great decay resistance relative to its forest associates. Total aboveground biomass pools in this 71-year-old forest (255 Mg/ha) are comparable to those in modern old-growth ecosystems in the region that also lack abundant white pine. Results highlight the importance of disturbance legacies in affecting forest structural conditions over extended periods following stand-replacing events and underscore that post-disturbance salvage logging can alter ecosystem development for decades. Moreover, the dominant role of old-growth P. strobus in live and detrital biomass pools before and after the hurricane, respectively, demonstrate the disproportionate influence this species likely had on carbon storage at localized scales prior to the widespread, selective harvesting of large P. strobus across the region in the 18th and 19th centuries.
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Affiliation(s)
- Anthony W D'Amato
- Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, Vermont, 05495, USA
| | - David A Orwig
- Harvard Forest, Harvard University, Petersham, Massachusetts, 01366, USA
| | - David R Foster
- Harvard Forest, Harvard University, Petersham, Massachusetts, 01366, USA
| | | | | | - Maggie R Wagner
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, 27695, USA
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Wagner MR, Lundberg DS, del Rio TG, Tringe SG, Dangl JL, Mitchell-Olds T. Host genotype and age shape the leaf and root microbiomes of a wild perennial plant. Nat Commun 2016; 7:12151. [PMID: 27402057 PMCID: PMC4945892 DOI: 10.1038/ncomms12151] [Citation(s) in RCA: 416] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 06/06/2016] [Indexed: 01/01/2023] Open
Abstract
Bacteria living on and in leaves and roots influence many aspects of plant health, so the extent of a plant's genetic control over its microbiota is of great interest to crop breeders and evolutionary biologists. Laboratory-based studies, because they poorly simulate true environmental heterogeneity, may misestimate or totally miss the influence of certain host genes on the microbiome. Here we report a large-scale field experiment to disentangle the effects of genotype, environment, age and year of harvest on bacterial communities associated with leaves and roots of Boechera stricta (Brassicaceae), a perennial wild mustard. Host genetic control of the microbiome is evident in leaves but not roots, and varies substantially among sites. Microbiome composition also shifts as plants age. Furthermore, a large proportion of leaf bacterial groups are shared with roots, suggesting inoculation from soil. Our results demonstrate how genotype-by-environment interactions contribute to the complexity of microbiome assembly in natural environments.
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Affiliation(s)
- Maggie R. Wagner
- Program in Genetics and Genomics, Department of Biology, Duke University, Durham, North Carolina 27708, USA
| | - Derek S Lundberg
- Department of Biology, Curriculum in Genetics and Molecular Biology, Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Tijana G. del Rio
- Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA
| | - Susannah G. Tringe
- Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA
| | - Jeffery L. Dangl
- Department of Biology, Curriculum in Genetics and Molecular Biology, Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Howard Hughes Medical Institute, Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Thomas Mitchell-Olds
- Program in Genetics and Genomics, Department of Biology, Duke University, Durham, North Carolina 27708, USA
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Wagner MR, Lundberg DS, Coleman-Derr D, Tringe SG, Dangl JL, Mitchell-Olds T. Corrigendum to Wagneret al.: Natural soil microbes alter flowering phenology and the intensity of selection on flowering time in a wild Arabidopsis relative. Ecol Lett 2014. [DOI: 10.1111/ele.12400] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maggie R. Wagner
- Duke University Program in Genetics and Genomics; Department of Biology, Box 90338; Duke University; Durham NC 27708 USA
| | - Derek S. Lundberg
- Department of Biology; Howard Hughes Medical Institute
- Curriculum in Genetics and Molecular Biology; Carolina Center for Genome Sciences; University of North Carolina; Chapel Hill NC 27599 USA
| | | | | | - Jeffery L. Dangl
- Department of Biology; Howard Hughes Medical Institute
- Curriculum in Genetics and Molecular Biology; Department of Microbiology and Immunology; Carolina Center for Genome Sciences; University of North Carolina; Chapel Hill NC 27599 USA
| | - Thomas Mitchell-Olds
- Institute for Genome Sciences & Policy; Department of Biology, Box 90338; Duke University; Durham NC 27708 USA
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Wagner MR, Lundberg DS, Coleman-Derr D, Tringe SG, Dangl JL, Mitchell-Olds T. Natural soil microbes alter flowering phenology and the intensity of selection on flowering time in a wild Arabidopsis relative. Ecol Lett 2014; 17:717-26. [PMID: 24698177 DOI: 10.1111/ele.12276] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [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: 01/07/2014] [Revised: 02/09/2014] [Accepted: 02/28/2014] [Indexed: 02/03/2023]
Abstract
Plant phenology is known to depend on many different environmental variables, but soil microbial communities have rarely been acknowledged as possible drivers of flowering time. Here, we tested separately the effects of four naturally occurring soil microbiomes and their constituent soil chemistries on flowering phenology and reproductive fitness of Boechera stricta, a wild relative of Arabidopsis. Flowering time was sensitive to both microbes and the abiotic properties of different soils; varying soil microbiota also altered patterns of selection on flowering time. Thus, soil microbes potentially contribute to phenotypic plasticity of flowering time and to differential selection observed between habitats. We also describe a method to dissect the microbiome into single axes of variation that can help identify candidate organisms whose abundance in soil correlates with flowering time. This approach is broadly applicable to search for microbial community members that alter biological characteristics of interest.
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Affiliation(s)
- Maggie R Wagner
- Duke University Program in Genetics and Genomics, Department of Biology, Duke University, Durham, NC, 27708, USA
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22
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Reparaz JS, Chavez-Angel E, Wagner MR, Graczykowski B, Gomis-Bresco J, Alzina F, Sotomayor Torres CM. A novel contactless technique for thermal field mapping and thermal conductivity determination: two-laser Raman thermometry. Rev Sci Instrum 2014; 85:034901. [PMID: 24689609 DOI: 10.1063/1.4867166] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a novel contactless technique for thermal conductivity determination and thermal field mapping based on creating a thermal distribution of phonons using a heating laser, while a second laser probes the local temperature through the spectral position of a Raman active mode. The spatial resolution can be as small as 300 nm, whereas its temperature accuracy is ±2 K. We validate this technique investigating the thermal properties of three free-standing single crystalline Si membranes with thickness of 250, 1000, and 2000 nm. We show that for two-dimensional materials such as free-standing membranes or thin films, and for small temperature gradients, the thermal field decays as T(r) ∝ ln(r) in the diffusive limit. The case of large temperature gradients within the membranes leads to an exponential decay of the thermal field, T ∝ exp[ - A·ln(r)]. The results demonstrate the full potential of this new contactless method for quantitative determination of thermal properties. The range of materials to which this method is applicable reaches far beyond the here demonstrated case of Si, as the only requirement is the presence of a Raman active mode.
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Affiliation(s)
- J S Reparaz
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
| | - E Chavez-Angel
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
| | - M R Wagner
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
| | - B Graczykowski
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
| | - J Gomis-Bresco
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
| | - F Alzina
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
| | - C M Sotomayor Torres
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
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Poliani E, Wagner MR, Reparaz JS, Mandl M, Strassburg M, Kong X, Trampert A, Sotomayor Torres CM, Hoffmann A, Maultzsch J. Nanoscale imaging of InN segregation and polymorphism in single vertically aligned InGaN/GaN multi quantum well nanorods by tip-enhanced Raman scattering. Nano Lett 2013; 13:3205-3212. [PMID: 23795596 DOI: 10.1021/nl401277y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Vertically aligned GaN nanorod arrays with nonpolar InGaN/GaN multi quantum wells (MQW) were grown by MOVPE on c-plane GaN-on-sapphire templates. The chemical and structural properties of single nanorods are optically investigated with a spatial resolution beyond the diffraction limit using tip-enhanced Raman spectroscopy (TERS). This enables the local mapping of variations in the chemical composition, charge distribution, and strain in the MQW region of the nanorods. Nanoscale fluctuations of the In content in the InGaN layer of a few percent can be identified and visualized with a lateral resolution below 35 nm. We obtain evidence for the presence of indium clustering and the formation of cubic inclusions in the wurtzite matrix near the QW layers. These results are directly confirmed by high-resolution TEM images, revealing the presence of stacking faults and different polymorphs close to the surface near the MQW region. The combination of TERS and HRTEM demonstrates the potential of this nanoscale near-field imaging technique, establishing TERS as a very potent, comprehensive, and nondestructive tool for the characterization and optimization of technologically relevant semiconductor nanostructures.
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Affiliation(s)
- E Poliani
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
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24
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Reparaz JS, Peica N, Kirste R, Goñi AR, Wagner MR, Callsen G, Alonso MI, Garriga M, Marcus IC, Ronda A, Berbezier I, Maultzsch J, Thomsen C, Hoffmann A. Probing local strain and composition in Ge nanowires by means of tip-enhanced Raman scattering. Nanotechnology 2013; 24:185704. [PMID: 23579463 DOI: 10.1088/0957-4484/24/18/185704] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Local strain and Ge content distribution in self-assembled, in-plane Ge/Si nanowires grown by combining molecular beam epitaxy and the metal-catalyst assisted-growth method were investigated by tip-enhanced Raman scattering. We show that this technique is essential to study variations of physical properties of single wires at the nanoscale, a task which cannot be achieved with conventional micro-Raman scattering. As two major findings, we report that (i) the Ge distribution in the (001) crystallographic direction is inhomogeneous, displaying a gradient with a higher Ge content close to the top surface, and (ii) in contrast, the (uncapped) wires exhibit essentially the same small residual compressive strain everywhere along the wire.
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Affiliation(s)
- J S Reparaz
- Technische Universität Berlin, Hardenbergstrasse 36, D-10623 Berlin, Germany.
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Abstract
Adaptive evolution is shaped by the interaction of population genetics, natural selection and underlying network and biochemical constraints. Variation created by mutation, the raw material for evolutionary change, is translated into phenotypes by flux through metabolic pathways and by the topography and dynamics of molecular networks. Finally, the retention of genetic variation and the efficacy of selection depend on population genetics and demographic history. Emergent high-throughput experimental methods and sequencing technologies allow us to gather more evidence and to move beyond the theory in different systems and populations. Here we review the extent to which recent evidence supports long-established theoretical principles of adaptation.
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Affiliation(s)
- Carrie F. Olson-Manning
- Department of Biology, Box 90338, Program in Genetics and Genomics, Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708
| | - Maggie R. Wagner
- Department of Biology, Box 90338, Program in Genetics and Genomics, Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708
| | - Thomas Mitchell-Olds
- Department of Biology, Box 90338, Program in Genetics and Genomics, Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708
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26
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Wagner MR. Ecological Details Matter in Island Biogeography: A Case Study on the Samoan Orchids. The American Midland Naturalist 2012. [DOI: 10.1674/0003-0031-167.1.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Callsen G, Reparaz JS, Wagner MR, Vierck A, Phillips MR, Thomsen C, Hoffmann A. Titanium-assisted growth of silica nanowires: from surface-matched to free-standing morphologies. Nanotechnology 2011; 22:405604. [PMID: 21911929 DOI: 10.1088/0957-4484/22/40/405604] [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] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on an oxide-assisted growth technique for silica nanowires which allows tuning the growth from surface-matched nanowires to free-standing morphologies based on growth control by Ti in the role of a catalyst and surfactant. Using an adjustable Ti concentration, we grew silica nanowires with lengths ranging from 100 nm up to several millimetres whose defect chemistry was analysed by electron microscopy tools, monochromatic cathodoluminescence imaging and time resolved photoluminescence spectroscopy. The knowledge of the luminescence properties and the related defect occurrence along with their spatial distribution is pivotal for advancing silica nanowire growth in order to realize successful device designs based on self-assembled Si/SiO(x) nanostructures. We demonstrate a core-shell structure of the grown nanowires with a highly luminescent 150 nm thick shell and outstandingly fast decaying dynamics (≈1 ns) for glass-like materials. The conjunction of the observed efficient and stable luminescences with their attributed decaying behaviours suggests applications for silica nanowires such as active and passive optical interconnectors and white light phosphors. The identification of a time domain difference for the spectral regime from 2.3 to 3.3 eV, within the confined spatial dimensions of a single nanowire, is very promising for future, e.g. data transmission applications, employing silica nanowires which exhibit achievable compatibility with commonly applied silicon-based electronics. A qualitative growth model based on silica particle diffusion and Ti-assisted seed formation is developed for the various types of segregated silica nanowires which extends commonly assumed oxide-assisted growth mechanisms.
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Affiliation(s)
- G Callsen
- Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Germany.
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Abstract
How predictable is evolution at the molecular level? An example of repeated evolution in rice and Brassica illustrates how selection might preferentially target certain genes and mutations.
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Affiliation(s)
- Maggie R Wagner
- University Program in Genetics and Genomics, Institute for Genome Sciences and Policy Box 90338, Duke University, Durham, NC 27708, USA
| | - Thomas Mitchell-Olds
- University Program in Genetics and Genomics, Institute for Genome Sciences and Policy Box 90338, Duke University, Durham, NC 27708, USA
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Gaylord ML, Hofstetter RW, Wagner MR. Impacts of silvicultural thinning treatments on beetle trap captures and tree attacks during low bark beetle populations in ponderosa pine forests of northern Arizona. J Econ Entomol 2010; 103:1693-1703. [PMID: 21061969 DOI: 10.1603/ec10082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Our research used a combination of passive traps, funnel traps with lures, baited trees, and surveys of long-term thinning plots to assess the impacts of different levels of stand basal area (BA) on bark beetle tree attack and on trap captures of Ips spp., Dendroctonus spp., and their predators. The study occurred at two sites in ponderosa pine, Pinus ponderosa Dougl. ex Laws., forests, from 2004 to 2007 during low bark beetle populations. Residual stand BA ranged from 9.0 to 37.0 m2/ha. More predators and bark beetles were collected in passive traps in stands of lower BA than in stands of higher BA; however, significance varied by species and site, and total number of beetles collected was low. Height of the clear panel passive traps affected trap catches for some species at some sites and years. When pheromone lures were used with funnel traps [Ips pini (Say) lure: lanierone, +03/-97 ipsdienol], we found no significant difference in trap catches among basal area treatments for bark beetles and their predators. Similarly, when trees were baited (Dendroctonus brevicomis LeConte lure: myrcene, exo-brevicomin and frontalin), we found no significant difference for days to first bark beetle attack. Surveys of long-term thinning treatments found evidence of bark beetle attacks only in unthinned plots (approximately 37 m2/ha basal area). We discuss our results in terms of management implications for bark beetle trapping and control.
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Affiliation(s)
- M L Gaylord
- School of Forestry, Northern Arizona University, P.O. Box 15018, Flagstaff, AZ 86011, USA.
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Gaylord ML, Williams KK, Hofstetter RW, McMillin JD, Degomez TE, Wagner MR. Influence of temperature on spring flight initiation for southwestern ponderosa pine bark beetles (Coleoptera: Curculionidae, Scolytinae). Environ Entomol 2008; 37:57-69. [PMID: 18348797 DOI: 10.1603/0046-225x(2008)37[57:iotosf]2.0.co;2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Determination of temperature requirements for many economically important insects is a cornerstone of pest management. For bark beetles (Coleoptera: Curculionidae, Scolytinae), this information can facilitate timing of management strategies. Our goals were to determine temperature predictors for flight initiation of three species of Ips bark beetles, five species of Dendroctonus bark beetles, and two genera of bark beetle predators, Enoclerus spp. (Coleoptera: Cleridae) and Temnochila chlorodia (Mannerheim) (Coleoptera: Ostomidae), in ponderosa pine forests of northcentral Arizona. We quantified beetle flight activity using data loggers and pheromone-baited funnel traps at 18 sites over 4 yr. Ambient air temperature was monitored using temperature data loggers located in close proximity to funnel traps. We analyzed degree-day accumulation and differences between minimum, average, and maximum ambient temperature for the week before and week of first beetle capture to calculate flight temperature thresholds. Degree-day accumulation was not a good predictor for initiation of beetle flight. For all species analyzed other than D. adjunctus Blandford, beetles were captured in traps only when springtime temperatures exceeded 15.0 degrees C. D. adjunctus was collected when maximum temperatures reached only 14.5 degrees C. Once initial flights had begun, beetles were often captured when maximum ambient air temperatures were below initial threshold temperatures. Maximum and average air temperatures were a better predictor for beetle flight initiation than minimum temperature. We establish a temperature range for effective monitoring of bark beetles and their predators, and we discuss the implications of our results under climate change scenarios.
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Affiliation(s)
- M L Gaylord
- School of Forestry, Northern Arizona University, PO Box 15018, Flagstaff, AZ 86011, USA.
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Wagner MR, Raimann PR, Trifonova A, Möller KC, Besenhard JO, Winter M. Dilatometric and mass spectrometric investigations on lithium ion battery anode materials. Anal Bioanal Chem 2004; 379:272-6. [PMID: 15042268 DOI: 10.1007/s00216-004-2570-9] [Citation(s) in RCA: 50] [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] [Received: 11/28/2003] [Revised: 02/12/2004] [Accepted: 02/24/2004] [Indexed: 10/26/2022]
Abstract
Lithium ion batteries operate beyond the thermodynamic stability of the aprotic organic electrolyte used. In 1 M LiClO(4) propylene carbonate electrolyte, with and without the addition of ethylene sulfite as a film forming electrolyte additive, we have used in situ electrochemical dilatometry and on-line electrochemical mass spectrometry to study the volume expansion/contraction of graphitic anodes and the formation of propylene gas, which both can occur during the graphite anode reduction (charge) process. The combination of both methods allows us to get insights into the respective electrolyte reduction mechanisms. The results indicate that the major failure mechanisms of graphitic anodes in pure PC electrolyte can be attributed to the intercalation of solvated lithium ions and the formation of propylene gas, which causes the graphite particles to exfoliate and crack.
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Affiliation(s)
- M R Wagner
- Institute for Chemical Technology of Inorganic Materials, Graz University of Technology, Stremayrgasse 16, 8010, Graz, Austria.
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Gilbert TT, Wagner MR, Halukurike V, Paz HL, Garland A. Use of bispectral electroencephalogram monitoring to assess neurologic status in unsedated, critically ill patients. Crit Care Med 2001; 29:1996-2000. [PMID: 11588470 DOI: 10.1097/00003246-200110000-00024] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To test whether spectral indices derived from the electroencephalogram (EEG), and especially the bispectral index (BIS), can be used as measures of neurologic status in unsedated, critically ill patients. DESIGN Prospective, observational study. SETTING Medical intensive care unit (ICU) of a university-affiliated teaching hospital. PATIENTS Thirty-one awake, unsedated critically ill adults were assessed in 108 separate sessions. MEASUREMENTS AND MAIN RESULTS In each session, severity of illness was assessed by the Acute Physiology and Chronic Health Evaluation (APACHE III). The APACHE III Acute Physiology Score was used to quantify the degree of physiologic derangement. Neurologic function was assessed using the APACHE III Neurologic Score, the Glasgow Coma Scale, the Reaction Level Scale, and the Modified Ramsay Sedation Scale. All indices were plotted against various spectral parameters of the EEG, including BIS, an empirical index of EEG activity that is scaled from 0 to 100. BIS was significantly (p <.05) correlated with neurologic score regardless of scoring system used and was more strongly correlated than any other EEG spectral parameter. Better neurologic function was associated with higher values of BIS. In multivariate analysis, the combination of BIS and relative power in the theta band of the EEG accounted for 38% of the variability in the Glasgow Coma Scale. CONCLUSIONS BIS provides a reliable index of neurologic status in awake, unsedated, critically ill patients. Further research is needed to determine whether the effects of neurologic status and pharmacologic sedation upon EEG are additive, whether BIS can be used to assess pharmacologic sedation in the critically ill patient population, and whether such objective measures of neurologic status have prognostic value.
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Affiliation(s)
- T T Gilbert
- UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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Wagner MR, Keane DM, Melchor JP, Auspaker KR, Van Nostrand WE. Fibrillar amyloid beta-protein binds protease nexin-2/amyloid beta-protein precursor: stimulation of its inhibition of coagulation factor XIa. Biochemistry 2000; 39:7420-7. [PMID: 10858290 DOI: 10.1021/bi0002840] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cerebrovascular deposition of fibrillar 39-42 amino acid amyloid beta-protein (Abeta), a condition known as cerebral amyloid angiopathy (CAA), is a key pathological feature of Alzheimer's disease and related disorders including hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D). Severe cases of CAA, particularly in HCHWA-D, lead to recurrent and often fatal hemorrhagic strokes. Although the reasons for this pathological consequence remain unclear, alterations in proteolytic hemostasis mechanisms have been implicated. For example, the Abeta parent molecule protease nexin-2/amyloid beta-protein precursor (PN-2/AbetaPP), which is elevated in HCHWA-D cerebral vessels with Abeta deposits, is a potent inhibitor of coagulation factor XIa (FXIa). Here we show that fibrillar HCHWA-D Abeta binds PN-2/AbetaPP, but not its isolated Kunitz-type proteinase inhibitor (KPI) domain, in a saturable, dose-dependent manner with a K(d) of approximately 28 nM. Neither PN-2/AbetaPP nor its KPI domain bound to nonfibrillar HCHWA-D Abeta. The fibrillar Abeta binding domain on PN-2/AbetaPP was localized to residues 18-119. PN-2/AbetaPP that bound to fibrillar HCHWA-D Abeta immobilized either in plastic wells or on the surface of cultured cerebrovascular smooth muscle cells was active in inhibiting FXIa. Quantitative kinetic measurements revealed that fibrillar HCHWA-D Abeta caused a >5-fold enhancement of FXIa inhibition by PN-2/AbetaPP. Similar stimulatory effects on FXIa inhibition by PN-2/AbetaPP were also observed with fibrillar wild-type Abeta. However, fibrillar Abeta had no effect on the inhibition of trypsin by PN-2/AbetaPP. These findings suggest that fibrillar Abeta deposits in cerebral vessels can effectively localize and enhance the anticoagulant functions of PN-2/AbetaPP, thereby contributing to a microenvironment conducive to hemorrhaging.
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Affiliation(s)
- M R Wagner
- Departments of Medicine and Pathology, State University of New York, Stony Brook 11794-8153, USA
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Blanchard FA, Wagner MR, Takahashi IT. Liquid scintillation counting: automated mathematical fitting and use of channels ratio methods by computer program. Adv Tracer Methodol 1968; 4:133-43. [PMID: 5638181 DOI: 10.1007/978-1-4684-7532-6_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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