Etude immunocytochimique des pectines du méristème de Sinapis alba L. et de leurs modifications lors de la transition florale

Abstract

Immunocytochemical study of pectins and pectin modifications at floral transition in meristems of Sinapis alba L. Plant cell wall pectins are implicated in a large number of physiological processes. However, the exact functions of pectins ' at a structural level as well as in the context of cell biology and development - are still debatable. On the other hand, observations raise the question as to whether pectic fragments are involved in the in vivo control of flowering (Marfà et al., 1991) and communication changes between the cells of the apical meristem in floral transition (Ormenese et al., 2000, 2002) imply biochemical modifications of the cell wall structure. Using immunocytochemistry (electron and confocal as described in Liners et al., (1994), we studied the nature, localization and content of pectins in meristems of Sinapis in vegetative plants and at floral transition. A marked but transient decrease of the homopolygalacturonic content of the cell wall occurs in the first hours of the transition to flowering. This pectin content decrease must be due to the release of pectolytic enzymes like pectin methylesterase (PME) in the meristem. To study PME expression in the meristem at floral transition, we raised and characterized polyclonal antibodies to highly conserved sequences of S. alba. PME genes.

Date of Award	17 Dec 2004
Original language	French
Awarding Institution	University of Namur
Supervisor	Pierre Van Cutsem (Supervisor), Yves Poumay (Jury), Johan Messiaen (Jury), Georges BERNIER (Jury) & Jean-Marie KINET (Jury)