CYP77B1 a fatty acid epoxygenase specific to flowering plants

Emmanuelle Pineau (1) , Vincent Sauveplane (2) , Etienne Grienenberger (1) , Jean-Etienne Bassard (1) , Frédéric Beisson (3) , Franck Pinot (1)

1 IBMP - Institut de Biologie Moléculaire des Plantes
2 MICALIS - MICrobiologie de l'ALImentation au Service de la Santé
3 EBMP - Environnement, Bioénergie, Microalgues et Plantes

Contrary to animals, little is known in plants about enzymes able to produce fatty acid epoxides. In our attempt to find and characterize a new fatty acid epoxygenase in Arabidopsis thaliana, data mining brought our attention on CYP77B1. Modification of the N-terminus was necessary to get enzymatic activity after heterologous expression in yeast. The common plant fatty acid C18:2 was converted into the diol 12,13-dihydroxy-octadec-cis9-enoic acid when incubated with microsomes of yeast expressing modified CYP77B1 and AtEH1, a soluble epoxide hydrolase. This diol originated from the hydrolysis by AtEH1 of the epoxide 12,13-epoxy-octadec-cis-9enoic acid produced by CYP77B1. A spatio-temporal study of CYP77B1 expression performed with RT-qPCR revealed the highest level of transcripts in flower bud while, in open flower, the enzyme was mainly present in pistil. CYP77B1 promoter-driven GUS expression confirmed reporter activities in pistil and also in stamens and petals. In silico co-regulation data led us to hypothesize that CYP77B1 could be involved in cutin synthesis but when flower cutin of loss-of-function mutants cyp77b1 was analyzed, no difference was found compared to cutin of wild type plants. Phylogenetic analysis showed that CYP77B1 is strictly conserved in flowering plants, suggesting a specific function in this lineage.

Mots clés: Fatty acid; Epoxide; Diol; CytochromeP450; Cutin; Flower

Domaines: Biologie végétale

Emmanuelle Pineau, Vincent Sauveplane, Etienne Grienenberger, Jean-Etienne Bassard, Frédéric Beisson, et al.. CYP77B1 a fatty acid epoxygenase specific to flowering plants. Plant Science, 2021, 307, pp.110905. ⟨10.1016/j.plantsci.2021.110905⟩. ⟨hal-03321049⟩