Harper, Carla J. , Olcott Marshall, Alison , Marshall, Craig P. , Taylor, Thomas N. , Krings, Michael , Taylor, Edith L. .
Biomarkers in paleomycology – A case study using fungus-infected Permian woods from Antarctica.
Woody plant parts represent a microenvironment for a wide variety of microorganisms ranging from saprotrophs to pathogens. Some of the pathogens may trigger more or less specific host-responses in the form of morphological alterations and/or biochemical compound defenses. Evaluation of the roles of wood-inhabiting microorganisms in past environments requires detailed studies of fossil woods, which include the spatial and temporal resolution of all components, i.e., the biochemical and morphological responses of the host-pathogen interaction. In this contribution, we compare ostensibly healthy Late Permian woods to specimens that show symptoms of fungal infection from multiple localities in Antarctica using thin sections and analytical geochemical techniques. Evidence of fungi (e.g., hyphae, spores, decay patterns) is present in the vast majority of woods, but typically there are not enough morphological characters to resolve the systematic affinities of these remains or complete disease pathology descriptions. Fungi are biochemical agents with numerous enzymes capable of degrading wood cell-wall components, including cellulose, hemicellulose, lignin, and certain secondary metabolites. Individual rot, decay, or parasitic fungi produce unique sets of enzymes and alter the host in a specific manner, each of which can be used for taxonomic association. Modern studies of wood fungal enzymes utilize Fourier transform infrared spectroscopy (FTIR), a technique that obtains infrared (IR) spectra of organic compounds or the by-products of enzymatically altered woods. Biomarkers are complex molecular fossils derived from biochemical pathways in once-living organisms. Preliminary results from fossil woods indicate that wood with visible signs and symptoms of fungal interactions produces several lignin-related biomarkers in response to the fungi, e.g., large polycyclic aromatic hydrocarbons (PAH) or complex ring structures, n-alkanes or chains of hydrocarbons that may represent plant lipids. We predict that FTIR can help quantify the amount of lignin remaining in fossil wood via bulk lignin extraction of samples. We further hypothesize that fossil wood specimens showing no morphological signs or symptoms of microbial damage will yield a wide array of antimicrobial compounds (phytoanticipins) and polyphenolic deposits. The abundance of anatomically preserved wood in the fossil record provides an almost unlimited source of material that can be used to search for the presence of fungi and potential host responses. The application of geochemical techniques in paleomycology, such as developing taxonomic- and disease-specific fungal biomarkers, provides the foundation of a new avenue for understanding fungal diversity and plant-fungal evolution in the late Paleozoic.
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1 - University Of Kansas, Ecology And Evolutionary Biology, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
2 - University of Kansas, Geology, 1475 Jayhawk Blvd, Lawrence, KS, 66045, USA
3 - Bayerische Staatssammlung Für Paläontologie Und Ge, Richard-Wagner Strasse 10, Munich, N/A, D-80333, Germany
plant microbe interactions.
Presentation Type: Oral Paper:Papers for Sections
Location: Salon 5/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 9:15 AM
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award