Ríos Muñoz, Ignacio EstebanFacultad de Ciencias de la Vida2021-07-192021-07-192020http://repositorio.unab.cl/xmlui/handle/ria/19430Tesis (Magíster en Biotecnología y Ciencias de la Vida)Plant cell walls are the main reservoir of fixed carbon on earth. Several studies have demonstrated that this carbon is accumulated in polysaccharide form in this structure. The main kinds of polysaccharides present in cell walls are pectins, and the most abundant pectin in plants is Homogalacturonan (HG). HG is composed of a backbone of alpha-1,4-linked-d-galacturonic acid which can be methylesterified at its C-6 carboxyl groups and, in some species, acetyl-esterified at O-2 and/or O-3. Studies have shown that the HG degree of methylation (DM) is particularly important, because it determines the biochemical and mechanical properties of the cell wall. The demethylesterification of HG is catalyzed by pectin methylesterases (PMEs). In Arabidopsis thaliana, there are 67 putative genes that encode for PMEs, making difficult the study of HG modification. Arabidopsis seeds accumulate a large amount of mucilage, composed mainly of the pectin domain rhamnogalacturonan-I (RG-I) and HG. In this study, we decided to use the seed mucilage to characterize PME51, a PME expressed during all seed development, participating in HG methylesterification detected in the seed mucilage. The mutant lines showed changes in the global PME activity in dry seeds as well as in the patterns of methylation in the adherent layer using immunodetection, and a decrease in the HG DM. These results indicate that PME51 plays a role in the control of HG DM when the mucilage is synthesized and assembled in the seed.enPectinaInvestigacionesArabidopsis ThalianaTesis