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Role of Endophytic Fungi in Managed and Natural Ecosystems
Principal Investigator: Dr. Thomas Bultman
Students engaged in this research project will have an opportunity to explore how endophytic fungi impact the internal environment of plants, while testing hypotheses concerning the consequences of those impacts on plant and insect herbivore fitness. Endophytic fungi grow intercellularly within the shoots of many grasses and appear to protect the plants from insect herbivores. The mechanism of this protection is purported to be toxic alkaloids produced by the plant/fungal symbiotum. We have shown that grass endophytes mediate wound-induced resistance to insect herbivores. That is, the fungal endophytes are stimulated to provide heightened levels of protection for the plant following initial damage to the plant.
One direction of current research is to assess the molecular basis of the induced response and determine if fungal and/or plant genes are responsible for the wound-induced response. Students will assist in formulating testable hypotheses concerning the interactions among endophytes, tall fescue grasses, and insect herbivores (e.g. aphids and caterpillars). Students will design methods of testing these hypotheses while learning various molecular techniques, and methods for fungal staining and detection, to determine the induction of fungal endophyte to down- or up-regulate the transcription of genes responsible for the production of defensive alkaloids. Students will use analytical chemistry and molecular biology to determine how the fungi impact herbivorous insects.
Representative Publications:
- Sullivan, T.J., J. Rodstom*, J. Vandop*, J. Librizzi*, C. Graham*, C. L. Schardl, and T. L. Bultman. 2007. Symbiont-mediated changes in defensive strategy in the invasive grass Lolium arundinaceum: evidence from changes in gene expression and foliar elemental composition. New Phytologist. In Press.
- Bultman, T.L., C. Pulas*, L. Grant*, G. Bell*, T.J. Sullivan. 2006. Effects of endophytic fungal isolate and plant cultivar on host preference by two insect herbivore species. Environmental Entomology 35:1690-1695.
- Bultman, T.L., G. Bell*, and W. Martin*. 2004. A fungal endophyte mediates reversal of wound-induced resistance and constrains tolerance in a grass. Ecology 85:679-685.
- Bultman, T.L. and G. Bell*. 2003. Interaction between fungal endophytes and environmental stressors influences plant resistance to insects. Oikos 103:182-190.
- Bultman, T.L. and A. Leuchtmann. 2003. A test of host specialization by insect vectors as a mechanism for reproductive isolation among entomophilous fungal species. Oikos 103:681-687.
- Bultman, T.L., M. McNeill and S. Goldson. 2003. Genotype-dependent impacts of fungal endophytes in a multitrophic interaction. Oikos 102:491-496.
- Faeth, S. H. and T. L. Bultman. 2002. Endophytes and multitrophic plant-insect interactions. In Multitrophic Level Interactions. Edited by T. Tscharntke and B. A. Hawkins. Cambridge University Press. Cambridge, UK.
- Bultman, T. L. and J.C. Murphy. 2000. Do fungal endophytes mediate wound-induced resistance? pp. 89-123 In: Microbial Endophytes. Edited by C. W. Bacon and J. F. White, Jr. Marcel Dekker, Inc. New York, NY. Pp. 421-452.
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