Presenter: Leah Gauthier

Title: “Soil Microorganisms As Biopesticides: From Soil To Organism To Natural Product” 

Abstract: This thesis defense will present research on advances in all critical stages of biopesticide candidate discovery including microorganism isolation, bioactivity screening, and the structural elucidation of microbial natural products with biopesticidal properties. Using a modified ichip, novel bacterial species were isolated from an agricultural Fusarium head blight (FHB) nursery, exhibiting antagonism against Fusarium spp. and other fungal pathogens. This supports the hypothesis that the FHB nursery harbors beneficial microorganisms adapted to fight Fusarium. A thin layer chromatography direct bioautography assay was optimized to screen for NPs active against Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot in canola. Antifungal NP leads were identified, showcasing the assay’s utility in detecting known and novel NPs. Subsequent structure elucidation of lead compounds by nuclear magnetic resonance spectroscopy, mass spectrometry and chemical derivatization revealed novel cyclic lipopeptides, boyetchkins A-C, from a new Pseudomonas species. Collectively, this work provides a framework for isolating and characterizing biopesticide candidates with commercial potential. 

Date/Time /Location: Friday, October 18, 2024, 9:00 am, AVC 286A

Everyone is welcome.