Proposal Defense – Tyler Dabritz
About the event
Group: Dr. Mark Lange
Title: Characterization of Volatile Secondary Metabolites in Sphagnum Mosses and Associated Xylaria Endophytes: Implications for Plant-Fungal Symbiosis
Abstract: The early evolution of land plants is exemplified by bryophytes, consisting of the mosses, liverworts, and hornworts, with Sphagnum mosses playing a critical role in peatland ecosystems through their substantial contribution to peat formation via the decay of older growth. Comprising 90% of the organic matter in peat, Sphagnum effectively utilizes a polyphenolic network to create a barrier against microbial degradation. Moreover, the emissions of volatile organic compounds (VOCs) from peatlands reveal that Sphagnum mosses contribute significantly to sesquiterpene and non-terpene emissions. The interactions between endophytic fungi and their host plants further underscore this dynamic, as endophytic fungi produce diverse secondary metabolites that enhance plant health. From the selected Sphagnum fallax and Xylaria flabelliformis genome, we have identified 22 and 17 genes with high sequence identity corresponding to monoterpene and sesquiterpene synthases. From these, 5 genes were selected from each genome for functional characterization. From both S. fallax and X. flabelliformis enzyme assays with farnesyl pyrophosphate, turnover to product was successful in all 10 genes. A comparative analysis study of volatile secondary metabolites from Sphagnum mosses and their respective endophytes is nonexistent. In this proposal we aim to identify the chemical species that comprise the volatile profiles of mosses, their respective endophytes, and moss-endophyte pairs, with a focus on sesquiterpene olefins in order to contribute a greater understanding of plant-fungal interactions. Preliminary results from cultured species of Xylaria endophytic fungi, isolated from Sphagnum mosses, indicate considerable variability in VOC profiles from that of wild collected moss-endophyte pairs.