Modification of plasma membrane organization in tobacco cells elicited by cryptogein.
Lipid mixtures within artificial membranes undergo a separation into liquid-disordered and liquid-ordered phases. However, the existence of this segregation into microscopic liquid-ordered phases has been difficult to prove in living cells, and the precise organization of the plasma membrane into such phases has not been elucidated in plant cells. We developed a multispectral confocal microscopy approach to generate ratiometric images of the plasma membrane surface of Bright Yellow 2 tobacco (Nicotiana tabacum) suspension cells labeled with an environment sensitive fluorescent probe. This allowed the in vivo characterization of the global level of order of this membrane, by which we could demonstrate that an increase in its proportion of ordered phases transiently occurred in the early steps of the signaling triggered by cryptogein and flagellin, two elicitors of plant defense reactions. The use of fluorescence recovery after photobleaching revealed an increase in plasma membrane fluidity induced by cryptogein, but not by flagellin. Moreover, we characterized the spatial distribution of liquid-ordered phases on the membrane of living plant cells and monitored their variations induced by cryptogein elicitation. We analyze these results in the context of plant defense signaling, discuss their meaning within the framework of the "membrane raft" hypothesis, and propose a new mechanism of signaling platform formation in response to elicitor treatment.
Université de Bourgogne , Unité Mixte de Recherche 1347 Agroécologie, Equipe de Recherche Labelisée 6300 Centre National de la Recherche Scientifique, BP 86510, F-21000 Dijon, France.
Patricia
P
Gerbeau-Pissot
Christophe
C
Der
Dominique
D
Thomas
Iulia-Andra
IA
Anca
Kevin
K
Grosjean
Yann
Y
Roche
Jean-Marie
JM
Perrier-Cornet
Sébastien
S
Mongrand
Françoise
F
Simon-Plas
D001703:Biophysics / Q000379:methods; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D005408:Flagellin / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism / Q000494:pharmacology*; D018613:Microscopy, Confocal / Q000379:methods; D038761:Photobleaching; D011726:Pyridinium Compounds / Q000378:metabolism; D015398:Signal Transduction; D013261:Sterols / Q000032:analysis; D014026:Nicotiana / Q000166:cytology*
D005456:Fluorescent Dyes; D005656:Fungal Proteins; D011726:Pyridinium Compounds; D013261:Sterols; C061032:cryptogein protein, Phytophthora cryptogea; C541550:di-4-ANEPPDHQ; D005408:Flagellin