Localization of beta-D-Glucosidase activity and glucovanillin in vanilla bean (Vanilla planifolia Andrews)

Odoux Eric, Escoute Jacques, Verdeil Jean-Luc, Brillouet Jean-Marc. 2003. Localization of beta-D-Glucosidase activity and glucovanillin in vanilla bean (Vanilla planifolia Andrews). Annals of Botany, 92 (3) : 437-444.

Résumé : The morphology, anatomy and histology of mature green vanilla beans were examined by light and transmission electron microscopy. Beans have a triangular cross-section with a central cavity containing seeds. Each angle is lined with tubular cells, or papillae, while the cavity sides consist of placental laminae, The epicarp and endocarp are formed by one or two layers of very small cells, while the mesocarp contains large, highly vacuolarized cells, the cytoplasm being restricted to a thin layer along the cell walls. The radial distributions of glucovanillin and [bêta]-glucosidase activity, measured on [rô]-nitrophenyi-[bêta]-glucopyranoside and glucovanillin, are superimposable and show how [bêta]-glucosidase activity increases from the epicarp towards the placental zone, whereas glucovanillin is exclusively located in the placentae and papillae. Subcellular localization of [bêta]-glucosidase activity was achieved by incubating sections of vanilla beans in a buffer containing 5-bromo-4-chloro-3-indolyl-[bêta]-D-glucopyranoside as a substrate, Activity was observed in the cytoplasm (and/or the periplasm) of mesocarp and endocarp cells, with a more diffuse pattern observed in the papillae. A possible mechanism for the hydrolysis of glucovanillin and release of the aromatic aglycon vanillin involves the decompartmentation of cytoplasmic (and/or periplasmic) [bêta]-glucosidase and vacuolar glucovanillin.

Mots-clés Agrovoc : Vanilla planifolia, Orchidaceae, graine, beta glucosidase, vanilline, activité enzymatique

Classification Agris : F60 - Physiologie et biochimie végétale
Q02 - Traitement et conservation des produits alimentaires

Auteurs et affiliations

• Odoux Eric, CIRAD-FLHOR-PRH (FRA)
• Escoute Jacques, CIRAD-AMIS-BIOTROP (FRA)
• Verdeil Jean-Luc, CIRAD-AMIS-BIOTROP (FRA)
• Brillouet Jean-Marc, CIRAD-FLHOR-ARF (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/515142/)

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