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Poster: Biology & Disease Mgmt: Oomycetes


Putative sucrose esters from Petunia x hybrida may contribute to this host’s reduced susceptibility to Phytophthora infestans
M. BECKTELL (1) (1) Colorado Mesa University, U.S.A.

Petunias have been established as a less susceptible host of P. infestans, but the reasons for this have not been elucidated. We have reported that petunia leaf extracts contain a potent zoosporicide. Previous biochemical analyses of crude leaf extracts suggested the presence of sucrose esters, a class of compounds known to be produced by the trichomes of Petunia and Nicotiana species. Subsequent experiments with commercially available sucrose esters have revealed that sucrose monolaurate (SM), an amphiphilic sucrose monoester known to interact with cell membranes, exhibits zoospore lysing activity. The goal of our current work is to confirm the presence of and identify the chemical structure of the putative sucrose esters present in petunia leaf extracts. Samples were purified using hydrophilic-lipophilic balanced cartridges and an established protocol for the purification of sucrose esters from Nicotiana tabacum. The purified samples were analyzed, along with SM as a control, via LCMS-ELSD, 1H and 13C NMR, and TLC. The data shows a lack of monoesters, excluding SM as the bioactive component, but supports the presence of several known sucrose di- and polyesters. Analyses are ongoing to deduce the specific chemical structures of these sucrose esters. Results from this work will bring us one step closer to understanding an aspect of the petunia-late blight interaction that has received little attention.