University of Guelph, Guelph, Canada
Posters & Accepted Abstracts: Pharmaceut Reg Affairs
Taxol is produced by Taxus trees and their resident endophytic fungi. A mystery has been why these endophytes synthesize Taxol apparently redundantly. A defining feature of these trees is that they can propagate branches from long-lived buds that lie underneath the bark; branch emergence is accompanied by bark cracks, potential pathogen entry points. Here, we show that Taxol acts as a fungicide against wood decaying fungi (WDF) to which these long-lived trees are susceptible. Reducing endophytes in plants resulted in increased WDF growth. Endophytes sequestered Taxol in intracellular hydrophobic bodies (Hb), which prevented plant cytoxicity. Taxol-producing endophytes with these Hb localized to vascular rays within wood, but hyperaccumulated where the rays intersected branch points and associated air pockets. Chloromethane, a chemical released by WDF, along with chitin or WDF, induced Hb release from endophytes. Hb was released from endophytes by exocytosis; chloromethane induced exocytosis genes. Combined, Taxol-producing endophytes contribute to the survival of their host by protecting their nutrient-rich vascular system and branch points against systemic fungal pathogen invasion.
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Pharmaceutical Regulatory Affairs: Open Access received 400 citations as per Google Scholar report