Algae. 2012; 27(1): 21-32.
Prostaglandin A2 triggers a strong oxidative burst in Laminaria: a novel defense inducer in brown algae?
Antonios Zambounis, Emmanuel Gaquerel , Martina Strittmatter, Jean-Pierre Salaün, Philippe Potin and Frithjof C. Küpper
We report an oxidative burst triggered by prostaglandin A2 (PGA2) in the brown algal kelp Laminaria digitata, constituting the first such discovery in an alga and the second finding of an oxidative burst triggered by a prostaglandin in a living organism. The response is more powerful than the oxidative burst triggered by most other chemical elicitors in Laminaria. Also, it is dose-dependent and cannot be inhibited by diphenylene iodonium, suggesting that another source than NAD(P)H oxidase is operational in the production of reactive oxygen species. Despite the very strong oxidative response, rather few effects at other levels of signal transduction pathways could be identified. PGA2 does not increase lipolysis (free fatty acids) in Laminaria, and only one oxylipin (15-hydroxyeicosatetraenoic acid; 15-HETE) was found to be upregulated in Laminaria. In a subsequent set of experiments in the genome model Ectocarpus siliculosus, none of 5 selected candidate genes, all established participants in various stress responses, showed any significant differences in their expression profiles.
Keywords : Cyclopentenone; diphenylene iodonium; Phaeophyta; polyunsaturated fatty acids; prostaglandin A2