1
|
Peng Z, Johnson NC, Jansa J, Han J, Fang Z, Zhang Y, Jiang S, Xi H, Mao L, Pan J, Zhang Q, Feng H, Fan T, Zhang J, Liu Y. Mycorrhizal effects on crop yield and soil ecosystem functions in a long-term tillage and fertilization experiment. New Phytol 2024; 242:1798-1813. [PMID: 38155454 DOI: 10.1111/nph.19493] [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: 09/19/2023] [Accepted: 12/04/2023] [Indexed: 12/30/2023]
Abstract
It is well understood that agricultural management influences arbuscular mycorrhizal (AM) fungi, but there is controversy about whether farmers should manage for AM symbiosis. We assessed AM fungal communities colonizing wheat roots for three consecutive years in a long-term (> 14 yr) tillage and fertilization experiment. Relationships among mycorrhizas, crop performance, and soil ecosystem functions were quantified. Tillage, fertilizers and continuous monoculture all reduced AM fungal richness and shifted community composition toward dominance of a few ruderal taxa. Rhizophagus and Dominikia were depressed by tillage and/or fertilization, and their abundances as well as AM fungal richness correlated positively with soil aggregate stability and nutrient cycling functions across all or no-tilled samples. In the field, wheat yield was unrelated to AM fungal abundance and correlated negatively with AM fungal richness. In a complementary glasshouse study, wheat biomass was enhanced by soil inoculum from unfertilized, no-till plots while neutral to depressed growth was observed in wheat inoculated with soils from fertilized and conventionally tilled plots. This study demonstrates contrasting impacts of low-input and conventional agricultural practices on AM symbiosis and highlights the importance of considering both crop yield and soil ecosystem functions when managing mycorrhizas for more sustainable agroecosystems.
Collapse
Affiliation(s)
- Zhenling Peng
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Nancy Collins Johnson
- School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, 86001, USA
| | - Jan Jansa
- Laboratory of Fungal Biology, Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague, Czech Republic
| | - Jiayao Han
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Zhou Fang
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yali Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Shengjing Jiang
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China
| | - Hao Xi
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Lin Mao
- College of Life Sciences, Northwest Normal University, Lanzhou, 730070, China
| | - Jianbin Pan
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Qi Zhang
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Huyuan Feng
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Tinglu Fan
- Dryland Agriculture Institute, Gansu Academy of Agricultural Sciences, Lanzhou, 730070, China
| | - Jianjun Zhang
- Dryland Agriculture Institute, Gansu Academy of Agricultural Sciences, Lanzhou, 730070, China
| | - Yongjun Liu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| |
Collapse
|
2
|
Affiliation(s)
- Nancy Collins Johnson
- Department of Biological Sciences, Northern Arizona University, 617 S Beaver St., Flagstaff, AZ, 86011, USA
- School of Earth and Sustainability, Northern Arizona University, 624 S Knoles Dr., Flagstaff, AZ, 86011, USA
| | - César Marín
- Centro de Investigación e Innovación para el Cambio Climatico (CiiCC), Universidad Santo Tomás, Ave Ramón Picarte 1130, Valdivia, 5090000, Chile
- Department of Ecological Sciences, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1085, Amsterdam, 1081 HV, the Netherlands
| |
Collapse
|
3
|
Johnson NC, Gibson KS. Understanding Multilevel Selection May Facilitate Management of Arbuscular Mycorrhizae in Sustainable Agroecosystems. Front Plant Sci 2021; 11:627345. [PMID: 33574827 PMCID: PMC7870699 DOI: 10.3389/fpls.2020.627345] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 12/30/2020] [Indexed: 05/08/2023]
Abstract
Studies in natural ecosystems show that adaptation of arbuscular mycorrhizal (AM) fungi and other microbial plant symbionts to local environmental conditions can help ameliorate stress and optimize plant fitness. This local adaptation arises from the process of multilevel selection, which is the simultaneous selection of a hierarchy of groups. Studies of multilevel selection in natural ecosystems may inform the creation of sustainable agroecosystems through developing strategies to effectively manage crop microbiomes including AM symbioses. Field experiments show that the species composition of AM fungal communities varies across environmental gradients, and that the biomass of AM fungi and their benefits for plants generally diminish when fertilization and irrigation eliminate nutrient and water limitations. Furthermore, pathogen protection by mycorrhizas is only important in environments prone to plant damage due to pathogens. Consequently, certain agricultural practices may inadvertently select for less beneficial root symbioses because the conventional agricultural practices of fertilization, irrigation, and use of pesticides can make these symbioses superfluous for optimizing crop performance. The purpose of this paper is to examine how multilevel selection influences the flow of matter, energy, and genetic information through mycorrhizal microbiomes in natural and agricultural ecosystems, and propose testable hypotheses about how mycorrhizae may be actively managed to increase agricultural sustainability.
Collapse
Affiliation(s)
- Nancy Collins Johnson
- School of Earth & Sustainability, Northern Arizona University, Flagstaff, AZ, United States
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
| | - Kara Skye Gibson
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
| |
Collapse
|
4
|
Stevens BM, Propster JR, Öpik M, Wilson GWT, Alloway SL, Mayemba E, Johnson NC. Arbuscular mycorrhizal fungi in roots and soil respond differently to biotic and abiotic factors in the Serengeti. Mycorrhiza 2020; 30:79-95. [PMID: 31970495 DOI: 10.1007/s00572-020-00931-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 07/23/2019] [Accepted: 01/10/2020] [Indexed: 05/14/2023]
Abstract
This study explores the relationships of AM fungal abundance and diversity with biotic (host plant, ungulate grazing) and abiotic (soil properties, precipitation) factors in the Serengeti National Park, Tanzania. Soil and root samples were collected from grazed and ungrazed plots at seven sites across steep soil fertility and precipitation gradients. AM fungal abundance in the soil was estimated from the density of spores and the concentration of a fatty acid biomarker. Diversity of AM fungi in roots and soils was measured using DNA sequencing and spore identification. AM fungal abundance in soil decreased with grazing and precipitation and increased with soil phosphorus. The community composition of AM fungal DNA in roots and soils differed. Root samples had more AM fungal indicator species associated with biotic factors (host plant species and grazing), and soil samples had more indicator species associated with particular sample sites. These findings suggest that regional edaphic conditions shape the site-level species pool from which plant species actively select root-colonizing fungal assemblages modified by grazing. Combining multiple measurements of AM fungal abundance and community composition provides the most informed assessment of the structure of mycorrhizal fungal communities in natural ecosystems.
Collapse
Affiliation(s)
- Bo Maxwell Stevens
- School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, 86011, USA.
| | - Jeffrey Ryan Propster
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Maarja Öpik
- Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, 40 Lai St, 51005, Tartu, Estonia
| | - Gail W T Wilson
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Sara Lynne Alloway
- School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | | | - Nancy Collins Johnson
- School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, 86011, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| |
Collapse
|
5
|
Revillini D, Wilson GWT, Miller RM, Lancione R, Johnson NC. Plant Diversity and Fertilizer Management Shape the Belowground Microbiome of Native Grass Bioenergy Feedstocks. Front Plant Sci 2019; 10:1018. [PMID: 31475019 PMCID: PMC6702339 DOI: 10.3389/fpls.2019.01018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/22/2019] [Indexed: 05/04/2023]
Abstract
Plants may actively cultivate microorganisms in their roots and rhizosphere that enhance their nutrition. To develop cropping strategies that substitute mineral fertilizers for beneficial root symbioses, we must first understand how microbial communities associated with plant roots differ among plant taxa and how they respond to fertilization. Arbuscular mycorrhizal (AM) fungi and rhizobacteria are of particular interest because they enhance nutrient availability to plants and perform a suite of nutrient cycling functions. The purpose of this experiment is to examine the root and soil microbiome in a long-term switchgrass (Panicum virgatum) biofuel feedstock experiment and determine how AM fungi and rhizobacteria respond to plant diversity and soil fertility. We hypothesize that intra- and interspecific plant diversity, nitrogen fertilization (+N), and their interaction will influence the biomass and community composition of AM fungi and rhizobacteria. We further hypothesize that +N will reduce the abundance of nitrogenase-encoding nifH genes on the rhizoplane. Roots and soils were sampled from three switchgrass cultivars (Cave-in-Rock, Kanlow, Southlow) grown in monoculture, intraspecific mixture, and interspecific planting mixtures with either Andropogon gerardii or diverse native tallgrass prairie species. Molecular sequencing was performed on root and soil samples, fatty acid extractions were assessed to determine microbial biomass, and quantitative polymerase chain reaction (qPCR) was performed on nifH genes from the rhizoplane. Sequence data determined core AM fungal and bacterial microbiomes and indicator taxa for plant diversity and +N treatments. We found that plant diversity and +N influenced AM fungal biomass and community structure. Across all plant diversity treatments, +N reduced the biomass of AM fungi and nifH gene abundance by more than 40%. The AM fungal genus Scutellospora was an indicator for +N, with relative abundance significantly greater under +N and in monoculture treatments. Community composition of rhizobacteria was influenced by plant diversity but not by +N. Verrucomicrobia and Proteobacteria were the dominant bacterial phyla in both roots and soils. Our findings provide evidence that soil fertility and plant diversity structure the root and soil microbiome. Optimization of soil communities for switchgrass production must take into account differences among cultivars and their unique responses to shifts in soil fertility.
Collapse
Affiliation(s)
- Daniel Revillini
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
- Department of Biology, University of Miami, Coral Gables, FL, United States
- *Correspondence: Daniel Revillini,
| | - Gail W. T. Wilson
- Department of Natural Resource Ecology, Management, Oklahoma State University, Stillwater, OK, United States
| | - R. Michael Miller
- Environmental Science Division, Argonne National Laboratory, Lemont, IL, United States
| | - Ryan Lancione
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
| | - Nancy Collins Johnson
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
- School of Earth, Sustainability, Northern Arizona University, Flagstaff, AZ, United States
| |
Collapse
|
6
|
Jiang S, Liu Y, Luo J, Qin M, Johnson NC, Öpik M, Vasar M, Chai Y, Zhou X, Mao L, Du G, An L, Feng H. Dynamics of arbuscular mycorrhizal fungal community structure and functioning along a nitrogen enrichment gradient in an alpine meadow ecosystem. New Phytol 2018; 220:1222-1235. [PMID: 29600518 DOI: 10.1111/nph.15112] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [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: 12/09/2017] [Accepted: 02/09/2018] [Indexed: 05/26/2023]
Abstract
Nitrogen (N) availability is increasing dramatically in many ecosystems, but the influence of elevated N on the functioning of arbuscular mycorrhizal (AM) fungi in natural ecosystems is not well understood. We measured AM fungal community structure and mycorrhizal function simultaneously across an experimental N addition gradient in an alpine meadow that is limited by N but not by phosphorus (P). AM fungal communities at both whole-plant-community (mixed roots) and single-plant-species (Elymus nutans roots) scales were described using pyro-sequencing, and the mycorrhizal functioning was quantified using a mycorrhizal-suppression treatment in the field (whole-plant-community scale) and a glasshouse inoculation experiment (single-plant-species scale). Nitrogen enrichment progressively reduced AM fungal abundance, changed AM fungal community composition, and shifted mycorrhizal functioning towards parasitism at both whole-plant-community and E. nutans scales. N-induced shifts in AM fungal community composition were tightly linked to soil N availability and/or plant species richness, whereas the shifts in mycorrhizal function were associated with the communities of specific AM fungal lineages. The observed changes in both AM fungal community structure and functioning across an N enrichment gradient highlight that N enrichment of ecosystems that are not P-limited can induce parasitic mycorrhizal functioning and influence plant community structure and ecosystem sustainability.
Collapse
Affiliation(s)
- Shengjing Jiang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yongjun Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jiajia Luo
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Mingsen Qin
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Nancy Collins Johnson
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Maarja Öpik
- Department of Botany, University of Tartu, Tartu, 51005, Estonia
| | - Martti Vasar
- Department of Botany, University of Tartu, Tartu, 51005, Estonia
| | - Yuxing Chai
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Xiaolong Zhou
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Lin Mao
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Guozhen Du
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Lizhe An
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Huyuan Feng
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| |
Collapse
|
7
|
Chaudhary VB, Rúa MA, Antoninka A, Bever JD, Cannon J, Craig A, Duchicela J, Frame A, Gardes M, Gehring C, Ha M, Hart M, Hopkins J, Ji B, Johnson NC, Kaonongbua W, Karst J, Koide RT, Lamit LJ, Meadow J, Milligan BG, Moore JC, Pendergast IV TH, Piculell B, Ramsby B, Simard S, Shrestha S, Umbanhowar J, Viechtbauer W, Walters L, Wilson GWT, Zee PC, Hoeksema JD. MycoDB, a global database of plant response to mycorrhizal fungi. Sci Data 2016; 3:160028. [PMID: 27163938 PMCID: PMC4862322 DOI: 10.1038/sdata.2016.28] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 03/23/2016] [Indexed: 11/12/2022] Open
Abstract
Plants form belowground associations with mycorrhizal fungi in one of the most common symbioses on Earth. However, few large-scale generalizations exist for the structure and function of mycorrhizal symbioses, as the nature of this relationship varies from mutualistic to parasitic and is largely context-dependent. We announce the public release of MycoDB, a database of 4,010 studies (from 438 unique publications) to aid in multi-factor meta-analyses elucidating the ecological and evolutionary context in which mycorrhizal fungi alter plant productivity. Over 10 years with nearly 80 collaborators, we compiled data on the response of plant biomass to mycorrhizal fungal inoculation, including meta-analysis metrics and 24 additional explanatory variables that describe the biotic and abiotic context of each study. We also include phylogenetic trees for all plants and fungi in the database. To our knowledge, MycoDB is the largest ecological meta-analysis database. We aim to share these data to highlight significant gaps in mycorrhizal research and encourage synthesis to explore the ecological and evolutionary generalities that govern mycorrhizal functioning in ecosystems.
Collapse
Affiliation(s)
- V. Bala Chaudhary
- Department of Environmental Science and Studies, DePaul University, Chicago, Illinois 60614, USA
| | - Megan A. Rúa
- National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, Tennessee 37996-3410, USA
- Department of Biology, University of Mississippi, University, Mississippi 38677, USA
| | - Anita Antoninka
- School of Forestry, Northern Arizona University, Flagstaff, Arizona 86011, USA
| | - James D. Bever
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045, USA
| | - Jeffery Cannon
- Colorado Forest Restoration Institute, Colorado State University, Fort Collins, Colorado 80523-1472, USA
| | - Ashley Craig
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011, USA
| | - Jessica Duchicela
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
- Departamento de Ciencias de la Vida, Universidad de las Fuerzas Armadas—ESPE, Sangolquí 1715231B, Ecuador
| | - Alicia Frame
- US Environmental Protection Agency, Office of Solid Waste and Emergency Response, Washington DC 20004, USA
| | - Monique Gardes
- Université Toulouse 3 Paul Sabatier, CNRS, ENFA; UMR5174 EDB (Évolution & Diversité Biologique); F-31062 Toulouse, France
| | - Catherine Gehring
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011, USA
| | - Michelle Ha
- Department of Biology, University of Mississippi, University, Mississippi 38677, USA
| | - Miranda Hart
- Department of Biology, University of British Columbia Okanagan, Kelowna BC, Canada V1V1V7
| | - Jacob Hopkins
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
| | - Baoming Ji
- College of Forestry, Beijing Forestry University, Beijing 100083, China
| | - Nancy Collins Johnson
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011, USA
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff Arizona 86011, USA
| | - Wittaya Kaonongbua
- Department of Microbiology, Faculty of Science, King Mongkut’s University of Technology Thonburi, Bangkok 10140, Thailand
| | - Justine Karst
- Department of Renewable Resources, University of Alberta, Edmonton, Canada T6G 2E3
| | - Roger T. Koide
- Department of Biology, Brigham Young University, Provo, Utah 84602, USA
| | - Louis J. Lamit
- School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931-1295, USA
| | - James Meadow
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403, USA
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana 59717, USA
| | - Brook G. Milligan
- Department of Biology, New Mexico State University, Las Cruces, New Mexico 88003, USA
| | - John C. Moore
- Department of Ecosystem Science and Sustainability, and the Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado 80523, USA
| | | | - Bridget Piculell
- Department of Biology, University of Mississippi, University, Mississippi 38677, USA
| | - Blake Ramsby
- Department of Biology, University of Mississippi, University, Mississippi 38677, USA
| | - Suzanne Simard
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Shubha Shrestha
- Department of Biological Sciences, Winston Salem State University, Winston-Salem, North Carolina 27110, USA
| | - James Umbanhowar
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Wolfgang Viechtbauer
- Department of Psychiatry and Neuropsychology, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Lawrence Walters
- Software Engineering, Enova International Inc., Chicago, Illinois 60604, USA
| | - Gail W. T. Wilson
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, Oklahoma 74078, USA
| | - Peter C. Zee
- Department of Biology, California State University—Northridge, Northridge, California 91330, USA
| | - Jason D. Hoeksema
- Department of Biology, University of Mississippi, University, Mississippi 38677, USA
| |
Collapse
|
8
|
Affiliation(s)
- Daniel Revillini
- Department of Biological Sciences Northern Arizona University PO Box 5640 Flagstaff AZ 86011 USA
| | - Catherine A. Gehring
- Department of Biological Sciences Northern Arizona University PO Box 5640 Flagstaff AZ 86011 USA
| | - Nancy Collins Johnson
- Department of Biological Sciences Northern Arizona University PO Box 5640 Flagstaff AZ 86011 USA
- School of Earth Sciences and Environmental Sustainability Northern Arizona University PO Box 5694 Flagstaff AZ 86011 USA
| |
Collapse
|
9
|
Davison J, Moora M, Öpik M, Adholeya A, Ainsaar L, Bâ A, Burla S, Diedhiou AG, Hiiesalu I, Jairus T, Johnson NC, Kane A, Koorem K, Kochar M, Ndiaye C, Pärtel M, Reier Ü, Saks Ü, Singh R, Vasar M, Zobel M. FUNGAL SYMBIONTS. Global assessment of arbuscular mycorrhizal fungus diversity reveals very low endemism. Science 2015. [PMID: 26315436 DOI: 10.5061/dryad.2m15n] [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] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The global biogeography of microorganisms remains largely unknown, in contrast to the well-studied diversity patterns of macroorganisms. We used arbuscular mycorrhizal (AM) fungus DNA from 1014 plant-root samples collected worldwide to determine the global distribution of these plant symbionts. We found that AM fungal communities reflected local environmental conditions and the spatial distance between sites. However, despite AM fungi apparently possessing limited dispersal ability, we found 93% of taxa on multiple continents and 34% on all six continents surveyed. This contrasts with the high spatial turnover of other fungal taxa and with the endemism displayed by plants at the global scale. We suggest that the biogeography of AM fungi is driven by unexpectedly efficient dispersal, probably via both abiotic and biotic vectors, including humans.
Collapse
Affiliation(s)
- J Davison
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| | - M Moora
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| | - M Öpik
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| | - A Adholeya
- Centre for Mycorrhizal Research, The Energy and Resources Institute (TERI), India Habitat Centre, Lodhi Road, New Delhi 110 003, India
| | - L Ainsaar
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| | - A Bâ
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Unité Mixte de Recherche 113, Laboratoire de Biologie et Physiologie Végétales, Faculté des Sciences Exactes et Naturelles, Université des Antilles, BP 592, 97159, Pointe-à-Pitre, Guadeloupe (French West Indies)
| | - S Burla
- Centre for Mycorrhizal Research, The Energy and Resources Institute (TERI), India Habitat Centre, Lodhi Road, New Delhi 110 003, India
| | - A G Diedhiou
- Laboratoire Commun de Microbiologie de l'Institut de Recherche pour le Développement-Institut Sénégalais de Recherches Agricoles-Université Cheikh Anta Diop (UCAD), Département de Biologie Végétale, UCAD, BP 5005 Dakar, Sénégal
| | - I Hiiesalu
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia. Institute of Botany, Czech Academy of Sciences, Dukelska 135, 379 01 Trebon, Czech Republic
| | - T Jairus
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| | - N C Johnson
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011-5694, USA
| | - A Kane
- Laboratoire Commun de Microbiologie de l'Institut de Recherche pour le Développement-Institut Sénégalais de Recherches Agricoles-Université Cheikh Anta Diop (UCAD), Département de Biologie Végétale, UCAD, BP 5005 Dakar, Sénégal
| | - K Koorem
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia. Netherlands Institute of Ecology, Droevendaalsesteeg 10, 6708 PB Wageningen, Netherlands
| | - M Kochar
- TERI-Deakin Nano Biotechnology Centre, Biotechnology and Management of Bioresources Division, TERI, India Habitat Centre, Lodhi Road, New Delhi 110 003, India
| | - C Ndiaye
- Laboratoire Commun de Microbiologie de l'Institut de Recherche pour le Développement-Institut Sénégalais de Recherches Agricoles-Université Cheikh Anta Diop (UCAD), Département de Biologie Végétale, UCAD, BP 5005 Dakar, Sénégal
| | - M Pärtel
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| | - Ü Reier
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| | - Ü Saks
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| | - R Singh
- TERI-Deakin Nano Biotechnology Centre, Biotechnology and Management of Bioresources Division, TERI, India Habitat Centre, Lodhi Road, New Delhi 110 003, India
| | - M Vasar
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| | - M Zobel
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia
| |
Collapse
|
10
|
Johnson NC, Wilson GWT, Wilson JA, Miller RM, Bowker MA. Mycorrhizal phenotypes and the Law of the Minimum. New Phytol 2015; 205:1473-1484. [PMID: 25417818 DOI: 10.1111/nph.13172] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [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: 07/01/2014] [Accepted: 10/06/2014] [Indexed: 05/09/2023]
Abstract
Mycorrhizal phenotypes arise from interactions among plant and fungal genotypes and the environment. Differences in the stoichiometry and uptake capacity of fungi and plants make arbuscular mycorrhizal (AM) fungi inherently more nitrogen (N) limited and less phosphorus (P) limited than their host plants. Mutualistic phenotypes are most likely in P-limited systems and commensal or parasitic phenotypes in N-limited systems. Carbon (C) limitation is expected to cause phenotypes to shift from mutualism to commensalism and even parasitism. Two experiments compared the influence of fertilizer and shade on mycorrhizas in Andropogon gerardii across three naturally N-limited or P-limited grasslands. A third experiment examined the interactive effects of N and P enrichment and shade on A. gerardii mycorrhizas. Our experiments generated the full spectrum of mycorrhizal phenotypes. These findings support the hypothesis that mutualism is likely in P-limited systems and commensalism or parasitism is likely in N-limited systems. Furthermore, shade decreased C-assimilation and generated less mutualistic mycorrhizal phenotypes with reduced plant and fungal biomass. Soil fertility is a key controller of mycorrhizal costs and benefits and the Law of the Minimum is a useful predictor of mycorrhizal phenotype. In our experimental grasslands arbuscular mycorrhizas can ameliorate P-limitation but not N-limitation.
Collapse
Affiliation(s)
- Nancy Collins Johnson
- School of Earth Sciences and Environmental Sustainability and Department of Biological Sciences, Northern Arizona University Flagstaff, Flagstaff, AZ, 86011, USA
| | - Gail W T Wilson
- Natural Resource Ecology & Management, Oklahoma State University, Stillwater, OK, 74077, USA
| | - Jacqueline A Wilson
- Natural Resource Ecology & Management, Oklahoma State University, Stillwater, OK, 74077, USA
| | - R Michael Miller
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Matthew A Bowker
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86011, USA
| |
Collapse
|
11
|
Werner GDA, Strassmann JE, Ivens ABF, Engelmoer DJP, Verbruggen E, Queller DC, Noë R, Johnson NC, Hammerstein P, Kiers ET. Evolution of microbial markets. Proc Natl Acad Sci U S A 2014; 111:1237-44. [PMID: 24474743 PMCID: PMC3910570 DOI: 10.1073/pnas.1315980111] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Biological market theory has been used successfully to explain cooperative behavior in many animal species. Microbes also engage in cooperative behaviors, both with hosts and other microbes, that can be described in economic terms. However, a market approach is not traditionally used to analyze these interactions. Here, we extend the biological market framework to ask whether this theory is of use to evolutionary biologists studying microbes. We consider six economic strategies used by microbes to optimize their success in markets. We argue that an economic market framework is a useful tool to generate specific and interesting predictions about microbial interactions, including the evolution of partner discrimination, hoarding strategies, specialized versus diversified mutualistic services, and the role of spatial structures, such as flocks and consortia. There is untapped potential for studying the evolutionary dynamics of microbial systems. Market theory can help structure this potential by characterizing strategic investment of microbes across a diversity of conditions.
Collapse
Affiliation(s)
- Gijsbert D. A. Werner
- Department of Ecological Science, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Joan E. Strassmann
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130
| | - Aniek B. F. Ivens
- Theoretical Biology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, 9700 CC, Groningen, The Netherlands
- Laboratory of Insect Social Evolution, The Rockefeller University, New York, NY 10065
| | - Daniel J. P. Engelmoer
- Department of Ecological Science, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Erik Verbruggen
- Institut für Biologie, Plant Ecology, Freie Universität Berlin, 14195 Berlin, Germany
| | - David C. Queller
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130
| | - Ronald Noë
- Faculté de Psychologie, Université de Strasbourg et Ethologie Evolutive, Département Ecologie, Physiologie et Ethologie, Centre National de la Recherche Scientifique, 67087 Strasbourg Cedex, France
- Netherlands Institute of Advanced Studies, 2242 PR, Wassenaar, The Netherlands
| | - Nancy Collins Johnson
- School of Earth Sciences and Environmental Sustainability and Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011-5694; and
| | - Peter Hammerstein
- Institute for Theoretical Biology, Humboldt University, 10115 Berlin, Germany
| | - E. Toby Kiers
- Department of Ecological Science, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands
| |
Collapse
|
12
|
|
13
|
|
14
|
Ji B, Gehring CA, Wilson GWT, Miller RM, Flores-Rentería L, Johnson NC. Patterns of diversity and adaptation in Glomeromycota from three prairie grasslands. Mol Ecol 2013; 22:2573-87. [DOI: 10.1111/mec.12268] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 01/16/2013] [Accepted: 01/20/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Baoming Ji
- Department of Biological Sciences; Northern Arizona University; Flagstaff AZ 86011 USA
| | - Catherine A. Gehring
- Department of Biological Sciences; Northern Arizona University; Flagstaff AZ 86011 USA
| | - Gail W. T. Wilson
- Department of Natural Resource Ecology & Management; Oklahoma State University; Stillwater OK 74078 USA
| | - R. M. Miller
- Biosciences Division; Argonne National Laboratory; Argonne IL 60439 USA
| | | | - Nancy Collins Johnson
- Department of Biological Sciences; Northern Arizona University; Flagstaff AZ 86011 USA
| |
Collapse
|
15
|
Liu Y, Shi G, Mao L, Cheng G, Jiang S, Ma X, An L, Du G, Collins Johnson N, Feng H. Direct and indirect influences of 8 yr of nitrogen and phosphorus fertilization on Glomeromycota in an alpine meadow ecosystem. New Phytol 2012; 194:523-535. [PMID: 22292929 DOI: 10.1111/j.1469-8137.2012.04050.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We measured the influences of soil fertility and plant community composition on Glomeromycota, and tested the prediction of the functional equilibrium hypothesis that increased availability of soil resources will reduce the abundance of arbuscular mycorrhizal (AM) fungi. Communities of plants and AM fungi were measured in mixed roots and in Elymus nutans roots across an experimental fertilization gradient in an alpine meadow on the Tibetan Plateau. As predicted, fertilization reduced the abundance of Glomeromycota as well as the species richness of plants and AM fungi. The response of the glomeromycotan community was strongly linked to the plant community shift towards dominance by Elymus nutans. A reduction in the extraradical hyphae of AM fungi was associated with both the changes in soil factors and shifts in the plant community composition that were caused by fertilization. Our findings highlight the importance of soil fertility in regulating both plant and glomeromycotan communities, and emphasize that high fertilizer inputs can reduce the biodiversity of plants and AM fungi, and influence the sustainability of ecosystems.
Collapse
Affiliation(s)
- Yongjun Liu
- School of Life Sciences, Lanzhou University, Lanzhou 730000, China
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou 730030, China
| | - Guoxi Shi
- School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Lin Mao
- School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Gang Cheng
- School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Shengjing Jiang
- School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xiaojun Ma
- School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Lizhe An
- School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Guozhen Du
- School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Nancy Collins Johnson
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Huyuan Feng
- School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| |
Collapse
|
16
|
Antoninka A, Reich PB, Johnson NC. Seven years of carbon dioxide enrichment, nitrogen fertilization and plant diversity influence arbuscular mycorrhizal fungi in a grassland ecosystem. New Phytol 2011; 192:200-214. [PMID: 21651560 DOI: 10.1111/j.1469-8137.2011.03776.x] [Citation(s) in RCA: 57] [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] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
• We tested the prediction that the abundance and diversity of arbuscular mycorrhizal (AM) fungi are influenced by resource availability and plant community composition by examining the joint effects of carbon dioxide (CO(2) ) enrichment, nitrogen (N) fertilization and plant diversity on AM fungi. • We quantified AM fungal spores and extramatrical hyphae in 176 plots after 7 yr of treatment with all combinations of ambient or elevated CO(2) (368 or 560 ppm), with or without N fertilization (0 or 4 g Nm(-2) ), and one (monoculture) or 16 host plant species (polyculture) in the BioCON field experiment at Cedar Creek Ecosystem Science Reserve, Minnesota, USA. • Extramatrical hyphal lengths were increased by CO(2) enrichment, whereas AM spore abundance decreased with N fertilization. Spore abundance, morphotype richness and extramatrical hyphal lengths were all greater in monoculture plots. A structural equation model showed AM fungal biovolume was most influenced by CO(2) enrichment, plant community composition and plant richness, whereas spore richness was most influenced by fungal biovolume, plant community composition and plant richness. • Arbuscular mycorrhizal fungi responded to differences in host community and resource availability, suggesting that mycorrhizal functions, such as carbon sequestration and soil stability, will be affected by global change.
Collapse
Affiliation(s)
- Anita Antoninka
- Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011-5694, USA
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN 55108-6112, USA
| | | |
Collapse
|
17
|
Johnson NC. XG: the forgotten blood group system. Immunohematology 2011; 27:68-71. [PMID: 22356523] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The XG blood group system is best known for its contributions to the fields of genetics and chromosome mapping. This system comprises two antigens, Xg(a) and CD99, that are not antithetical but that demonstrate a unique phenotypic relationship. XG is located on the tip of the short arm of the X chromosome with exons 1 to 3 present in the pseudoautosomal region of the X (and Y) chromosome(s) and exons 4 to 10 located only on the X chromosome. Xg(a) demonstrates a clear X-linked pattern of inheritance. MIC2, the gene encoding the CD99 antigen, is found in the pseudoautosomal region of both the X and Y chromosomes. Anti-Xg(a) is comparatively rare, and only two examples of anti-CD99 have ever been identified. Alloanti-Xg(a) is considered clinically insignificant; only one example of autoanti-Xg(a) has been reported, but it resulted in severe hemolytic anemia. Insufficient data exist to determine the clinical significance of anti-CD99. Linkage of XG to several X-borne genes encoding inherited disorders has been demonstrated. CD99 is an adhesion molecule, and high levels are associated with some types of cancer.
Collapse
MESH Headings
- 12E7 Antigen
- Anemia, Hemolytic/blood
- Anemia, Hemolytic/genetics
- Anemia, Hemolytic/immunology
- Anemia, Hemolytic/metabolism
- Antigens, CD/blood
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Autoantibodies/blood
- Biomarkers, Tumor/metabolism
- Blood Group Antigens/blood
- Blood Group Antigens/genetics
- Blood Group Antigens/metabolism
- Cell Adhesion Molecules/blood
- Cell Adhesion Molecules/genetics
- Cell Adhesion Molecules/metabolism
- Gene Expression Regulation, Neoplastic
- Gene Frequency
- Genes, X-Linked/genetics
- Genes, Y-Linked/genetics
- Genotype
- Humans
- Phenotype
Collapse
Affiliation(s)
- N C Johnson
- Immunohematology Reference Laboratory, Greater Chesapeake and Potomac Region, 4700 Mt. Hope Drive, Baltimore, MD 21215, USA
| |
Collapse
|
18
|
Hoeksema JD, Chaudhary VB, Gehring CA, Johnson NC, Karst J, Koide RT, Pringle A, Zabinski C, Bever JD, Moore JC, Wilson GWT, Klironomos JN, Umbanhowar J. A meta-analysis of context-dependency in plant response to inoculation with mycorrhizal fungi. Ecol Lett 2010; 13:394-407. [PMID: 20100237 DOI: 10.1111/j.1461-0248.2009.01430.x] [Citation(s) in RCA: 482] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jason D Hoeksema
- Department of Biology, University of Mississippi, University, MS 38677, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Abstract
Symbioses may be important mechanisms of plant adaptation to their environment. We conducted a reciprocal inoculation experiment to test the hypothesis that soil fertility is a key driver of local adaptation in arbuscular mycorrhizal (AM) symbioses. Ecotypes of Andropogon gerardii from phosphorus-limited and nitrogen-limited grasslands were grown with all possible "home and away" combinations of soils and AM fungal communities. Our results indicate that Andropogon ecotypes adapt to their local soil and indigenous AM fungal communities such that mycorrhizal exchange of the most limiting resource is maximized. Grasses grown in home soil and inoculated with home AM fungi produced more arbuscules (symbiotic exchange structures) in their roots than those grown in away combinations. Also, regardless of the host ecotype, AM fungi produced more extraradical hyphae in their home soil, and locally adapted AM fungi were, therefore, able to sequester more carbon compared with nonlocal fungi. Locally adapted mycorrhizal associations were more mutualistic in the two phosphorus-limited sites and less parasitic at the nitrogen-limited site compared with novel combinations of plants, fungi, and soils. To our knowledge, these findings provide the strongest evidence to date that resource availability generates evolved geographic structure in symbioses among plants and soil organisms. Thus, edaphic origin of AM fungi should be considered when managing for their benefits in agriculture, ecosystem restoration, and soil-carbon sequestration.
Collapse
Affiliation(s)
- Nancy Collins Johnson
- Environmental and Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
| | | | | | | | | |
Collapse
|
20
|
Abstract
Despite the fact that arbuscular mycorrhizal (AM) associations are among the most ancient, abundant and important symbioses in terrestrial ecosystems, there are currently few unifying theories that can be used to help understand the factors that control their structure and function. This review explores how a stoichiometric perspective facilitates integration of three complementary ecological and evolutionary models of mycorrhizal structure and function. AM symbiotic function should be governed by the relative availability of carbon, nitrogen and phosphorus (trade balance model) and allocation to plant and fungal structures should depend on the availabilities of these resources (functional equilibrium model). Moreover, in an evolutionary framework, communities of plants and AM fungi are predicted to adapt to each other and their local soil environment (co-adaptation model). Anthropogenic enrichment of essential resources in the environment is known to impact AM symbioses. A more predictive theory of AM structure and function will help us to better understand how these impacts may influence plant communities and ecosystem properties.
Collapse
Affiliation(s)
- Nancy Collins Johnson
- Environmental & Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011-5694, USA.
| |
Collapse
|
21
|
Johnson NC, Rowland DL, Corkidi L, Allen EB. PLANT WINNERS AND LOSERS DURING GRASSLAND N-EUTROPHICATION DIFFER IN BIOMASS ALLOCATION AND MYCORRHIZAS. Ecology 2008; 89:2868-78. [DOI: 10.1890/07-1394.1] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
22
|
Egerton-Warburton LM, Johnson NC, Allen EB. MYCORRHIZAL COMMUNITY DYNAMICS FOLLOWING NITROGEN FERTILIZATION: A CROSS-SITE TEST IN FIVE GRASSLANDS. ECOL MONOGR 2007. [DOI: 10.1890/06-1772.1] [Citation(s) in RCA: 218] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
23
|
Moore JC, Berlow EL, Coleman DC, Ruiter PC, Dong Q, Hastings A, Johnson NC, McCann KS, Melville K, Morin PJ, Nadelhoffer K, Rosemond AD, Post DM, Sabo JL, Scow KM, Vanni MJ, Wall DH. Detritus, trophic dynamics and biodiversity. Ecol Lett 2004. [DOI: 10.1111/j.1461-0248.2004.00606.x] [Citation(s) in RCA: 548] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
24
|
|
25
|
|
26
|
Abstract
The purpose of this study was to compare outcomes and delivery of cleft care in Western Australia with the average standard of care in the United Kingdom (UK). This was achieved through a cross-sectional study involving children born with unilateral cleft lip and palate between April 1983 and March 1985 (12 year olds) or between April 1990 and March 1992 (5 year olds). A total of 38 children born with unilateral cleft lip and palate were under the care of the cleft team based at Perth's Princess Margaret Hospital. Dental arch relations, facial skeletal pattern, speech, hearing, success of alveolar bone grafting and dental health were measured. It was found that fewer Princess Margaret Hospital children in both age cohorts had revision surgery and speech therapy compared with the UK average. The facial skeletal pattern, speech, hearing and alveolar bone grafting outcomes from Princess Margaret Hospital were similar to the UK at age 12. Seventeen per cent of the Princess Margaret Hospital 12 year olds had a poor dental arch relationship compared with 39 per cent in the UK. In the 5 year olds, most outcomes in Princess Margaret Hospital patients appeared better than the UK with lower residual treatment needs. While it is difficult to draw firm conclusions because of the small numbers involved, this study indicates standards need to be set and determined for Australia.
Collapse
|
27
|
Abstract
Although it is widely accepted that teeth play an important role in speech production, the relationship between tooth position and speech remains controversial. This review paper examines the relevant studies and discusses the difficulties of scientific investigation in this area. The ability of patients to adapt their speech to compensate for abnormal tooth position is recognized, but the mechanisms for this adaptation remain incompletely understood. The overall conclusion is that while certain dental irregularities show a relationship with speech disorders, this does not appear to correlate with the severity of the malocclusion. There is no definitive proof that alteration of tooth position can improve articulation disorders.
Collapse
Affiliation(s)
- N C Johnson
- Bristol Dental School, University of Bristol, UK
| | | |
Collapse
|
28
|
Inouye RS, Allison TD, Johnson NC. Old Field Succession on a Minnesota Sand Plain: Effects of Deer and Other Factors on Invasion by Trees. ACTA ACUST UNITED AC 1994. [DOI: 10.2307/2997181] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
29
|
Abstract
It has been noted previously that nutrient-stressed plants generally release more soluble carbohydrate in root exudates and consequently support more mycorrhizae than plants supplied with ample nutrients. Fertilization may select strains of vesicular-arbuscular mycorrhizal (VAM) fungi that are inferior mutualists if the same characteristics that make a VAM fungus successful in roots with a lowered carbohydrate content also reduce the benefits that the fungus provides a host plant. This two-phase study experimentally tests the hypothesis that fertilizing low-nutrient soil selects VAM fungi that are inferior mutualists. The first phase examines the effects of chemical fertilizers on the species composition of VAM fungal communities in long-term field plots. The second phase measures the effects of VAM fungal assemblages from fertilized and unfertilized plots on big bluestem grass grown in a greenhouse. The field results indicate that 8 yr of fertilization altered the species composition of VAM fungal communities. Relative abundance of Gigaspora gigantea, Gigaspora margarita, Scutellispora calospora, and Glomus occultum decreased while Glomus intraradix increased in response to fertilization. Results from the greenhouse experiment show that big bluestem colonized with VAM fungi from fertilized soil were smaller after 1 mo and produced fewer inflorescences at 3 mo than big bluestem colonized with VAM fungi from unfertilized soil. Fungal structures within big bluestem roots suggest that VAM fungi from fertilized soil exerted a higher net carbon cost on their host than VAM fungi from unfertilized soil. VAM fungi from fertilized soil produced fewer hyphae and arbuscules (and consequently provided their host with less inorganic nutrients from the soil) and produced as many vesicles (and thus provisioned their own storage structures at the same level) as fungi from unfertilized soil. These results support the hypothesis that fertilization selects VAM fungi that are inferior mutualists.
Collapse
|
30
|
|
31
|
Abstract
The effect of an orally administered diuretic, hydrochlorothiazide, on tear production in 11 normal young human subjects (five men and six women, 18 to 35 years old) was measured in a single-masked study. Schirmer tests with topical anesthetic showed a significant (P = .02) decrease in basal aqueous tear production on days when these subjects were taking the diuretic. The average decrease was 2.1 mm of wetting in five minutes.
Collapse
|
32
|
Johnson NC. Use of Schedule II controlled substances in Iowa--1977 to 1981. J Iowa Med Soc 1983; 73:90-1. [PMID: 6842037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|