Dr. Meredith C. Schuman

   Department of Molecular Ecology
 Phone:+49 (0)3641 57 1116Max Planck Institute for Chemical Ecology
 Fax:+49 (0)3641 57 1102Hans-Knöll-Straße 8
  emailD-07745 Jena

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Current Research:

We investigate the ecological functions of plant genes using the wild tobacco Nicotiana attenuata and its ecosystem as a model. The perspectives from which I am asking questions is a diurnal perspective as part the Clockwork Green project, and a focus on emergent properties as part of the German Centre for Integrative Biodiversity Research (iDiv). We are also associated with the SFB ChemBioSys.

The functional characterization of genes is often done in controlled laboratory environments. In the Department of Molecular Ecology, we emphasize both physiological and ecological characterizations of gene function, in both controlled glasshouse and climate chamber environments, and in Nicotiana attenuata's native habitat.

The iDiv Biodiversity Project group takes this approach a step further, to investigate the functions of individual genes in populations and communities, not just in individual plants interacting with their environment. We hypothesize that variation in single functional genes within plant populations can result in emergent properties feeding back on plant productivity and reproduction, by altering interactions with plants’ abiotic and biotic environment in a frequency-dependent manner. We are investigating whether single-gene functional diversity might result in higher productivity or greater stability for monocultures under biotic or abiotic stress, thus delivering some of the ecosystem services known to be supported by species-level biodiversity. We are conducting glasshouse and field studies with plants genetically engineered in specific traits controlled by single functional genes. Plants in our experiments are placed in different controlled populations consisting either of two neighboring plants, or of more than two plants. We observe the genetic, chemical, phenotypic, and ecological responses of plants in these communities. More information about my current research is available here: Molecular Ecology Project Groups.

Herbivore-induced plant volatiles (HIPVs) are arguably an example of a collection of traits whose functions can best be revealed by studying plants in populations and communities. HIPVs are emitted by plants within minutes to days after an herbivore begins to feed and can provide spatiotemporal information about an herbivore’s identity and presence to its predators and parasitoids. These natural enemies can disable or completely remove herbivores before the plant suffers further damage. The core question I am working on as part of Clockwork Green is how the plant's diurnal rhythm and circadian clock regulates the emission of volatiles, or the interactions they mediate. In order to answer this question fully, we can investigate several levels. The broadest is the level of ecological interactions: how are plants' ecological interactions mediated by volatiles? How important is the timing of volatile emissions in these interactions, and in what way? At the level of mechanism, we can ask: how are plant volatile emissions controlled, by signal cascades, hormones, and localization in tissues, and to what extent by the plant's internal clock or diurnal cues? Finally, at the level of genetics, we can ask: what are the genetic mechanisms of biosynthesis and regulation underlying plant volatile emission, including natural variation of emission patterns in populations?

Populations of the native tobacco Nicotiana attenuata are genetically diverse and individuals produce strikingly different HIPV blends which may vary quantitatively and qualitatively. Some of the more common HIPVs (green leaf volatiles, GLVs and the sesquiterpene trans-alpha-bergamotene) have been shown to attract predatory insects of the genus Geocoris, which seem to tolerate nicotine in the herbivores they ingest. Furthermore, GLVs have been shown to prime defense responses in other plant species, and regulate gene expression and some defenses in N. attenuata. I am interested in how HI-VOC bouquets mediate both tritrophic plant-insect interactions and plant-plant interactions. Furthermore, I am interested in how other plant traits, including water usage and photosynthetic rates, and clock-mediated coordination of metabolism, affect neighboring plants in populations as well as the interactions of plant populations with their abiotic and biotic environments.

I have developed in interest in evolutionary game theory thanks in part to a wonderful course led by Dr. Christian Kost (group leader in the Department of Bioorganic Chemistry) Prof. Stefan Schuster and Sabine Hummert (Department of Bioinformatics, Friedrich Schiller University, Jena). I am interested in the application of evolutionary game theory to questions in chemical ecology, and perhaps plant chemical diversity and plant-insect interactions.
last updated on 2016-10-05