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Short Title : Plant hydroperoxide eliciting activity is linked
to PPM modulation
Highlight : Modulation of the lipid dynamics of plant plasma
membrane by exogenous fatty acid hydroperoxide oxylipins triggers early
defence events like ROS production leading to plant resistance against
pathogens
Abstract: Oxylipins are
lipid-derived molecules that are ubiquitous in eukaryotes and whose
functions in plant physiology have been widely reported. They appear to
play a major role in plant immunity by orchestrating reactive oxygen
species (ROS) and hormone-dependent signalling pathways. The present
work focuses on the specific case of fatty acid hydroperoxides (HPOs).
Although some studies report their potential use as exogenous biocontrol
agents for plant protection, evaluation of their efficiency in
planta is lacking and no information is available about their mechanism
of action. In this work, the potential of
13(S )-hydroperoxyoctadeca-(9Z ,11E )-dienoic acid
(13-HPOD) and
13(S )-hydroperoxy-(9Z ,11E ,15Z )-octadecatrienoic
acid (13-HPOT), as plant defence elicitors and the underlying mechanism
of action are investigated. Arabidopsis thaliana leaf resistance
to Botrytis cinerea was observed after root application with
HPOs. They also activate early immunity-related defence responses, like
ROS. As previous studies have demonstrated their ability to interact
with plant plasma membranes (PPM), we have further investigated the
effects of HPOs on biomimetic PPM structure using complementary
biophysics tools. Results show that HPO insertion into PPM impacts its
global structure without solubilizing it. Relationship between
biological assays and biophysical analysis suggests that lipid
amphiphilic elicitors that directly act on membrane lipids might trigger
early plant defence events.
Keywords: Elicitor, Fatty Acid Hydroperoxide, Molecular
Mechanism, Oxidative Burst, Oxylipin, Plant Defence, Plant Plasma
Membrane.
Abbreviations : (13-HPOD) 13-hydroperoxy- 9,11-octadecadienoic
acid; (13-HPOT) 13-hydroperoxy- 9,11,15-octadecatrienoic acid; (AFM)
atomic force microscopy; (CMC) critical micelle concentration; (COS)
chitooligosaccharides, (d62DPPC)
1,2-dipalmitoyl-d62-sn-glycero-3-phosphocholine; (DAMP)
damage-associated molecular pattern; (DMSO) dimethylsulfoxide; (Flg22)
flagellin; (GIPC) glycosyl-inositol-phosphoryl-ceramide; (GluCer)
glucosylceramide; (GP) generalized polarization; (HPO) fatty acid
hydroperoxide; (ISR) induced systemic resistance; (LOX-1) Lipoxidase
from Glycine max (soybean) type I-B; (MLV) multilamellar vesicles; (MS)
Murashige and Skoog medium; (NR) neutron reflectometry; (OGA)
oligogalacturonides; (PAMP) pathogen-associated molecular pattern;
(PLPC) 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine; (POX)
peroxidase; (PPM) plant plasma membrane; (PRR) pattern recognition
receptor; (RBOH) respiratory burst oxidase homolog; (RLU) relative light
unit; (ROS) reactive oxygen species, (RL) rhamnolipid, (RT) room
temperature; (SR) systemic resistance; (SAR) systemic acquired
resistance; (SLB) supported lipid bilayer; (SLD) scattering length
density; (SUV) small unilamellar vesicle; (THSD) Tukey honest
significant differences; (TRIS) tri(hydroxymethyl)aminomethane.