Research:

  • Research Interests:

    With my students and collaborators, I am studying the molecular genetics, biochemistry, and biological significance of ergot alkaloids. Ergot alkaloids are toxins produced by several fungi including pathogens of plants and animals, and symbiotic endophytes of plants. I am interested in how ergot alkaloids are made (i.e., the pathways and genes involved) and why they are made (i.e., the advantages they give their producing organisms).

    Most fungi that produce ergot alkaloids accumulate complex profiles of ergot alkaloids rather than a single pathway end product. These ergot alkaloid profiles result from inefficiency in the pathway leading to accumulation of certain intermediates or diversion of intermediates into shunts along the pathway. My hypothesis is that the multiple products account for multiple benefits for the producing organisms. We are using gene knockouts to truncate the pathway at different steps to alter the ergot alkaloid profiles of fungi. The interactions of the knockout mutants with other organisms can then be studied to learn about the biological roles of different ergot alkaloids. For example, results of experiments on pathway knockouts indicate that certain ergot alkaloids deter feeding by mammals whereas other ergot alkaloids deter insects. One ergot alkaloid suppresses the appetite of rabbits whereas others do not. The data indicate that the apparent inefficiency in the ergot alkaloid pathway allows the producing fungus to gain multiple benefits from a from a single biochemical pathway.

  • Research Publications:
    • Panaccione, D.G., Schardl, C.L., and Coyle, C.M. 2006. Pathways to diverse ergot alkaloid profiles in fungi. In Recent Advances in Phytochemistry, vol. 40, Romeo, J.T. (Ed.). Elsevier, Amsterdam , pp. 23-52.

     

    • Schardl, C.L., Panaccione, D.G., and Tudzynski, P. 2006. Ergot alkaloids – Biology and Molecular Biology. In The Alkaloids: Chemistry and Biology, vol. 62, Cordell, G.A. (Ed.). Academic Press, San Diego , CA , pp. 47-88.

     

    • Panaccione, D.G., Kotcon, J.B., Schardl, C.L., Johnson, R.J., and Morton, J.B. 2006. Ergot alkaloids are not essential for endophytic fungus-associated population suppression of the lesion nematode, Pratylenchus scribneri, on perennial ryegrass. Nematology 8:583-590.

     

    • Panaccione, D.G., Cipoletti, J.R., Sedlock, A.B., Blemings, K.P., Schardl, C.L., Machado, C., and Seidel, G.E. 2006. Effects of ergot alkaloids on food preference and satiety in rabbits, as assessed with gene knockout endophytes in perennial ryegrass ( Lolium perenne ). Journal of Agricultural and Food Chemistry 54:4582-4587.

     

    • Panaccione, D.G. 2005. Origins and significance of ergot alkaloid diversity in fungi. FEMS Microbiology Letters 251:9-17.

     

    • Panaccione, D.G., and Coyle, C.M. 2005. Abundant respirable ergot alkaloids from the common airborne fungus Aspergillus fumigatus . Applied and Environmental Microbiology 71:3106-3111.

     

    • Coyle, C.M., and Panaccione, D.G. 2005. An ergot alkaloid biosynthesis gene and clustered hypothetical genes from Aspergillus fumigatus . Applied and Environmental Microbiology 71:3112-3118.

     

    • Damrongkool, P., Sedlock, A.B., Young , C.A. , Johnson, R.D., Goetz, K.E., Scott, B., Schardl, C.L., and Panaccione, D.G. 2005. Structural analysis of a peptide synthetase gene required for ergopeptine production in the endophytic fungus Neotyphodium lolii . DNA Sequence 16:379-385.

     

    • Haarmann, T., Machado, C., Lübbe, Y., Correia, T., Schardl, C.L., Panaccione, D.G., and Tudzynski, P. 2005. The ergot alkaloid gene cluster in Claviceps purpurea : extension of the cluster sequence and intra species evolution. Phytochemistry 66:1312-1320.

     

    • Wang , J., Machado , C. , Panaccione, D.G., Tsai, H.-F., and Schardl, C.L. 2004. The determinant step in ergot alkaloid biosynthesis by an endophyte of perennial ryegrass. Fungal Genetics & Biology 41:189-198.

     

    • Johnson, L.J, Johnson, R.D., Schardl, C.L., and Panaccione, D.G. 2003. Identification of differentially expressed genes in the mutualistic association of tall fescue with Neotyphodium coenophialum. Physiological and Molecular Plant Pathology 63:305-317.

     

    • Panaccione, D.G., Tapper, B.A., Lane, G.A., Davies, E., and Fraser, K. 2003. Biochemical outcome of blocking the ergot alkaloid pathway of a grass endophyte. Journal of Agricultural and Food Chemistry 51:6429-6437.

     

    • Panaccione, D.G., Johnson, R.D., Wang, J., Young , C.A. , Damrongkool, P., Scott, B. and Schardl. C.L. 2001. Elimination of ergovaline from a grass- Neotyphodium endophyte symbiosis by genetic modification of the endophyte. Proceedings of the National Academy of Science , USA 98:12820-12825 .