Influence of the Structure of Key Intermediates of Plant Oxylipins on their Interactions at the Molecular Level with Plant Plasma Membrane. 
Mehmet Nail NASIR, Magali DELEU, Laurence LINS, Marie-Laure FAUCONNIER
Gembloux Agro-Bio Tech, University of Liege, Passage des déportés, 2, 5030 Gembloux/Belgium
mn.nasir@ulg.ac.be

Plant oxylipins comprise a diverse family of molecules 1. Those compounds exist as a free form or can be esterified to phospholipids or galactolipids.  During plant-pathogen interactions, the amount of oxylipins can increase significantly2.
Plant oxylipins are derived from the oxidation of the polyunsaturated fatty acids such as linoleic and linolenic acids in order to generate conjugated hydroperoxy fatty acids (13-HPOD and 13-HPOT) which are considered as key intermediates oxylipins in the pathway 3. In plants, they are involved in different functions such as stress responses. Since they are lipophilic, their action could be exerted through an initial interaction with plant plasma membranes (PPM).
In spite of that, the knowledge on the impact of oxylipins on PPM is very limited. In this context, the aim of this work is to analyze at the molecular level the interactions between 13-HPOD and 13-HPOT with PPM. For this purpose, biomimetic membrane models of PPM such as monolayers and liposomes have been used. The interactions of oxylipins with these model membranes have been investigated with various biophysical techniques such as Langmuir monolayer technology and Fourier-transformed infrared spectroscopy and in silico homemade tools in order to obtain information at the molecular level 4. The results showed that the key intermediate oxylipins could be able to interact with different class of lipids. These interactions with phospholipid and sterol monolayers are favored from an energetic point of view. In this way, they can form stable complex monolayers. At the molecular level, even though the interactions were mainly driven by hydrophobic associations, the polar parts of oxylipins play a crucial role. Moreover, some differences in the membrane interaction were noticed between 13-HPOD and 13-HPOT differing only by the presence of a double bond, leading to consider the importance of slight structural modifications. 
References
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