Diacylglycerol kinases activate tobacco NADPH oxidase‐dependent oxidative burst in response to cryptogein |
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Authors: | Jean‐Luc Cacas Patricia Gerbeau‐Pissot Jérôme Fromentin Catherine Cantrel Dominique Thomas Emmanuelle Jeannette Tetiana Kalachova Sébastien Mongrand Françoise Simon‐Plas Eric Ruelland |
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Affiliation: | 1. Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche‐Comté, Dijon, France;2. UPMC UnivParis06, UR5, Physiologie Cellulaire et Moléculaire des Plantes, Paris cedex 05, France;3. UPE, UPEC, Institut d'Ecologie et des Sciences de l'Environnement de Paris, Créteil, France;4. CNRS, UMR7618, Institut d'Ecologie et des Sciences de l'Environnement de Paris, Créteil, France;5. CNRS, UMR 5200 Laboratoire de Biogenèse Membranaire, INRA Bordeaux Aquitaine, BP81, Villenave d'Ornon, France |
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Abstract: | Cryptogein is a 10 kDa protein secreted by the oomycete Phytophthora cryptogea that activates defence mechanisms in tobacco plants. Among early signalling events triggered by this microbial‐associated molecular pattern is a transient apoplastic oxidative burst which is dependent on the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity of the RESPIRATORY BURST OXIDASE HOMOLOG isoform D (RBOHD). Using radioactive [33P]‐orthophosphate labelling of tobacco Bright Yellow‐2 suspension cells, we here provide in vivo evidence for a rapid accumulation of phosphatidic acid (PA) in response to cryptogein because of the coordinated onset of phosphoinositide‐dependent phospholipase C and diacylglycerol kinase (DGK) activities. Both enzyme specific inhibitors and silencing of the phylogenetic cluster III of the tobacco DGK family were found to reduce PA production upon elicitation and to strongly decrease the RBOHD‐mediated oxidative burst. Therefore, it appears that PA originating from DGK controls NADPH‐oxidase activity. Amongst cluster III DGKs, the expression of DGK5‐like was up‐regulated in response to cryptogein. Besides DGK5‐like is likely to be the main cluster III DGK isoform silenced in one of our mutant lines, making it a strong candidate for the observed response to cryptogein. The relevance of these results is discussed with regard to early signalling lipid‐mediated events in plant immunity. |
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Keywords: | cryptogein DGK microbial‐associated molecular pattern phosphatidic acid phospholipase C RBOHD reactive oxygen species |
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