Pacific Southwest Research Station

Education

Yale University, B.S. 1997
University of Hawaii Manoa, M.S. 2000
University of California Berkeley, PhD. 2010

Research Interests/Duties

My current research interests were inspired by edaphic (soil physical, chemical, and biological properties) adaptation of plants leading to evolution, speciation, and differential distribution of edaphic specialist plants. As a mycorrhiza researcher, I wondered if this plant edaphic specialization could really be symbiotic specialization. I have been actively researching the ecology and biology of a common symbiosis between soil fungi and plant roots called arbuscular mycorrhiza since 1997, and working with edaphically adapted plants offered a unique and exciting research opportunity. Consequently my dissertation research used a unique experimental system in which populations of serpentine and non-serpentine soil adapted ecotypes of the California native plant Collinsia sparsiflora are within a close geographic range (110m to 1.94 km between sites) to describe the primary ecological and evolutionary relationships between serpentine soil, arbuscular mycorrhizal fungi (AMF) and adapted plants. My dissertation research addressed three main questions: 1. Do serpentine and non-serpentine ecotypes of Collinsia sparsiflora associate with distinct AMF assemblages? 2. Do edaphic factors of serpentine soil shape AMF assemblages that are distinct from non-serpentine assemblages? 3. Do serpentine-derived AMF mediate plant adaptation by improving fitness on serpentine?

My dissertation showed that there is a strong ecological relationship between AMF and serpentine tolerance and provided evidence that plants choose different AMF as soil nutrient levels change, potentially a newly identified stress adapted plant trait. However, nothing is known about the specific role the symbiosis plays in plant tolerance to serpentine.

Current Emphases, Studies, Projects

My current research goal is to establish the primary plant and fungal traits associated with nutrient stress tolerance. To do this, I will compare symbiotic traits between serpentine and non-serpentine plants and AM fungi to address three questions: 1. Do plant symbiotic traits (requirement for and response to AMF) differ between serpentine and non-serpentine adapted plants? 2. Do serpentine and non-serpentine AMF differ in their ability to improve plant growth, nutrient uptake, and fitness in serpentine soil? 3. Can plants choose "beneficial" AMF under changing nutrient status?

This research will allow us to explore plant and fungal symbiotic traits as sources of new targets for plant breeding programs and to develop new strategies to improve stress resistance in agricultural plants. In addition, this study may lead to the identification and culturing of fungi with stress resistance and growth promoting traits that can be used directly to decrease the impact of environmental stress on agricultural productivity, sustainability, and restoration.

Ultimately, I am interested in investigating these interactions from phylogenetic and community ecology perspectives, including population genetic approaches. Through these studies I hope to enhance our understanding of plant-fungal-soil interactions and their ecology and evolution as a tool for restoration, conservation, and agriculture.

Selected Publications

Serpentine and non-serpentine ecotypes of Collinsia sparsiflora associate with distinct arbuscular mycorrhizal fungal assemblages. S.P. Schechter and T.D. Bruns. Molecular Ecology, 17 (13): 3198-3210, 2008

Tall whitetop eradication and native plant community restoration. S. Peters and J. Etra.  Proceedings California Invasive Plant Council Symposium, 7: 33-39, 2003.

Mycorrhizal Inoculum:  evaluating need and performance in revegetation and reclamation projects.  S. Peters. Grasslands, 12 (4): 1, 8-10, 2002.

Optimizing solution P concentration in a peat-based medium for producing mycorrhizal seedlings in containers. S.M. Peters and M. Habte. Arid Land Research and Management, 15: 359-370, 2001.