Diacylglycerol kinases activate tobacco NADPH oxidase-dependent oxidative burst in response to cryptogein

Jean-Luc Cacas (1) , Patricia Gerbeau-Pissot (1) , Jérôme Fromentin (1) , Catherine Cantrel (2) , Dominique Thomas (1) , Emmanuelle Jeannette (2) , Tetiana Kalachova (3) , Sébastien Mongrand (4, 3) , Françoise Simon-Plas (1) , Eric Ruelland (2, 3)

1 Agroécologie [Dijon]
2 PCMP - Physiologie cellulaire et moléculaire des plantes
3 iEES - Institut d'écologie et des sciences de l'environnement de Paris
4 LBM - Laboratoire de biogenèse membranaire

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 NADPH oxidase activity of the RESPIRATORY BURST OXIDASE HOMOLOG (RBOH) isoform D. 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 due to 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 line, 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.

Mots clés: reactive oxygen species; cryptogein; microbial-associated molecular pattern; phosphatidic acid; RBOHD; diacylglycerol kinase; phospholipase C; NADPH oxidase

Domaines: Phytopathologie et phytopharmacie; Biodiversité et Ecologie

Jean-Luc Cacas, Patricia Gerbeau-Pissot, Jérôme Fromentin, Catherine Cantrel, Dominique Thomas, et al.. Diacylglycerol kinases activate tobacco NADPH oxidase-dependent oxidative burst in response to cryptogein. Plant, Cell and Environment, 2016, 40 (4), pp.585-598. ⟨10.1111/pce.12771⟩. ⟨hal-01328631⟩