Plant Science — OUR SCIENTISTS

Louise Egerton-Warburton, Ph.D.

Conservation Scientist, Soil and Microbial Ecology

Ph.D. 1994, Curtin University of Technology, Australia

PUBLICATIONS
(847) 835-6915
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Research Interests

Fungal diversity, functioning, and ecology with an emphasis on mycorrhizal fungi
Consequences of alterations in climate, land-use, and species invasion cycles on plant-soil interactions
Fungal contributions to soil carbon sequestration and stability
Resilience, complex systems, and network theory

TEACHING AND RESEARCH AFFILIATIONS

Fulbright Fellow, Fulbright Scholar Program, 1994–97
Adjunct Professor, Biological Sciences, Northwestern University, 2003 – present

SELECTED PROFESSIONAL ASSOCIATIONS

2003 – present    Member, Soil Science Society of America
2000 – present    Member, Mycological Society of America
1996 – present    Member, Ecological Society of America
1995 – present    Member, Microscopy Society of America
1994 – present    Member, Australian and American Fulbright Alumni
1994 – present    Member, Australia Society for Microscopy

Statement

My research focuses on the ecological links between the above- and below-ground biota, and in particular how mycorrhizal fungi are fundamental to the wellbeing of all aboveground communities and ecosystems. Mycorrhizal fungi form relationships with plant roots, and grow fine root-like hyphae into the soil, where they acquire and transfer resources (water, phosphorus, nitrogen) to the plant in return for sugars to sustain growth. Their biomass can outweigh that of any other component in the soil biota, and their roles range from the control of nutrient cycling and the immobilization of greenhouse gases in their tissues (e.g., CO2) through to enhancing plant productivity and protection from diseases.

Two recurring themes in my research are the mechanistic understanding of how these plant-fungal interactions affect community and ecosystem processes, and the consequences of alterations in climate, land-use, and species invasions on this relationship.

My current research projects can be broadly grouped into four areas:

Soil carbon sequestration: identifying and quantifying the pathways of carbon flow through rhizosphere fungal communities;
Understanding legacy effects in soils: plant community composition and management effects on microbial communities and biogeochemistry;
Mycorrhizal diversity and functioning: identifying the pathways by which mycorrhizal fungi are involved in the uptake and (re-) distribution of water; and
Ecological controls of mycorrhizal fungal diversity and community structure: the extent to which mycorrhizal fungi demonstrate resilience and adaptation to changes in the global environment.

My approach to all research is pluralistic. I use both laboratory and field experiments to test ecological theory, and I use molecular genetic techniques, stable isotopes, microscopy, standard in vitro culture techniques, and quantitative techniques, as well as well as algorithmic and statistic analyses. The questions I ask range from local or individual through to ecosystem-level responses in tallgrass prairies, oak-maple woodlands, and dry seasonal tropical forests.

My research program actively involves high-school students (summer only), undergraduates (summer only), and graduate students (year-round).

Selected Publications

Querejeta, J.I., Egerton-Waburton, L.M., Prieto, I., Vargas, R., Allen, M.F. (2012). Changes in soil hyphal abundance and viability can alter the patterns of hydraulic redistribution by plant roots. Plant and Soil 355: 63-73.

Querejeta, Egerton-Warburton, L.M., and Allen, M.F. (2009). Differential access to groundwater modulates the mycorrhizal responsiveness of oaks to inter-annual rainfall variability in a California woodland. Ecology 90: 649-662.

Egerton-Warburton, L.M., Querejeta, J.I., and Allen, M.F. (2008). Efflux of hydraulically-lifted water by mycorrhizal hyphae during imposed drought. Plant Signaling and Behavior 3: 68-71.

Egerton-Warburton, L.M., Johnson, N.C., and Allen, E.B. (2007). Mycorrhizal community dynamics following nitrogen fertilization: a cross-site test in five grasslands. Ecological Monographs 77: 527-544.

Plamboek, A.H., Dawson, T.E., Egerton-Warburton, L.M., North, M., Bruns, T.D., and Querejeta, J.I. (2007). Water transfer via ectomycorrhizal fungal hyphae to conifer seedlings. Mycorrhiza 17: 439-447.

Querejeta, J.I., Egerton-Warburton, L.M., and Allen, M.F. (2003). Direct nocturnal water transfer from oaks to their mycorrhizal symbionts during severe soil drying. Oecologia 134: 55-64.

Egerton-Warburton, L.M., Graham, R.C., Allen, E.B, and Allen, M.F. (2001). Reconstruction of the historical changes in mycorrhizal fungal communities under anthropogenic nitrogen deposition. Proceedings of the Royal Society of London, Series B 268: 2479-2484.

Egerton-Warburton, L.M., and Allen, E.B. (2000). Shifts in the diversity of arbuscular mycorrhizal fungi along an anthropogenic nitrogen deposition gradient. Ecological Applications 10: 484- 496.

CURRENT GRADUATE STUDENTS

Robert Hevey, M.S. program, Northwestern University

Nik Desai, M.S. program, Northwestern University

Corey Palmer, M.S. program, Northwestern University

Benjamin Morgan, Ph.D. program, Northwestern University

Lauren Umek, Ph.D. program, Northwestern University

PAST GRADUATE STUDENTS

Kara Borden (University of Illinois, Chicago, M.S., 2007) Anthropogenic nitrogen deposition affects seasonal patterns of soil available nitrogen and distribution between organic and inorganic pools in oak-maple forests.

Lauren Umek (Northwestern University, M.S., 2007) Seasonal variation in key soils characteristics in a tallgrass prairie restoration gradient.

Joseph Gawronski-Salerno (Northwestern University, M.S., 2008) Mycorrhizal alterations in the presence of an exotic invasive plant, Alliaria petiolata (garlic mustard, Brassicaceae).

Rachel Gross (Northwestern University, M.S., 2008) Effects of fire frequency on arbuscular mycorrhizal productivity in the tallgrass prairie.

Jonathan DeLong (Northwestern University, M.S., 2009) The influence of endophytic partners on patterns of weediness in a native Australian orchid, Microtis media.

Zaid McKee-Krisberg (University of Illinois, Chicago, M.S., 2009) Redistribution of labile nitrogen between growing and non-growing regions: Implications for differential responses of plant growth and N uptake to high CO2.

Duane Ambroz (Northwestern University, M.S., 2010) Soil carbon sequestration in the urban savanna.

WEBSITES

International Culture Collection of (Vesicular) Arbuscular Mycorrhizal Fungi (INVAM)
INVAM is a living culture collection, where the primary goal is to acquire, propagate, characterize, and maintain germplasm of AMF in living cultures for preservation and distribution to any person or institution. The collection is curated and maintained by Dr. Joe Morton at WVU. The site contains germplasm information and accessions, basic tools in fungal biology, taxonomy, and ecology of AMF. http://invam.caf.wvu.edu/. Sister site: La Banque Européenne des Glomales (BEG), http://www.kent.ac.uk/bio/beg/

DEEMY
DEEMY is an information system for the morphological characterization of ectomycorrhizal fungi. http://www.deemy.de/

UNITE
UNITE is molecular database for the identification of fungi, primarily fungal rDNA ITS sequences, and designed to facilitate identification of environmental samples of fungal DNA. http://unite.ut.ee/

The Santa Fe Institute
The Santa Fe Institute is a private, nonprofit research institute that has defined complex systems research and promoted the understanding of complex adaptive systems critical to addressing key environmental, technological, and biological challenges. http://www.santafe.edu/