RRC ID 33336
Author Levesque-Tremblay G, Müller K, Mansfield SD, Haughn GW.
Title HIGHLY METHYL ESTERIFIED SEEDS is a pectin methyl esterase involved in embryo development.
Journal Plant Physiol
Abstract Homogalacturonan pectin domains are synthesized in a highly methyl-esterified form that later can be differentially demethyl esterified by pectin methyl esterase (PME) to strengthen or loosen plant cell walls that contain pectin, including seed coat mucilage, a specialized secondary cell wall of seed coat epidermal cells. As a means to identify the active PMEs in seed coat mucilage, we identified seven PMEs expressed during seed coat development. One of these, HIGHLY METHYL ESTERIFIED SEEDS (HMS), is abundant during mucilage secretion, peaking at 7 d postanthesis in both the seed coat and the embryo. We have determined that this gene is required for normal levels of PME activity and homogalacturonan methyl esterification in the seed. The hms-1 mutant displays altered embryo morphology and mucilage extrusion, both of which are a consequence of defects in embryo development. A significant decrease in the size of cells in the embryo suggests that the changes in embryo morphology are a consequence of lack of cell expansion. Progeny from a cross between hms-1 and the previously characterized PME inhibitor5 overexpression line suggest that HMS acts independently from other cell wall-modifying enzymes in the embryo. We propose that HMS is required for cell wall loosening in the embryo to facilitate cell expansion during the accumulation of storage reserves and that its role in the seed coat is masked by redundancy.
Volume 167(3)
Pages 725-37
Published 2015-3-1
DOI 10.1104/pp.114.255604
PII pp.114.255604
PMID 25572606
PMC PMC4348785
MeSH Antibodies / metabolism Arabidopsis / embryology* Arabidopsis / enzymology* Arabidopsis / genetics Arabidopsis Proteins / metabolism* Biomechanical Phenomena Carboxylic Ester Hydrolases / metabolism* Cell Size Esterification Gene Expression Regulation, Enzymologic Gene Expression Regulation, Plant Genes, Plant Mutagenesis, Insertional Pectins / metabolism Phenotype Plant Mucilage / metabolism Plants, Genetically Modified Seeds / embryology* Seeds / enzymology* Seeds / genetics Seeds / ultrastructure
IF 6.902
Times Cited 26
Arabidopsis / Cultured plant cells, genes psh19427 pda06484 psh19427