Characterization of a putative Pectin Methylesterase, PME51, using the Arabidopsis thaliana seed coat mucilage
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Fecha
2020
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Idioma
en
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
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.
Notas
Tesis (Magíster en Biotecnología y Ciencias de la Vida)
Palabras clave
Pectina, Investigaciones, Arabidopsis Thaliana