Pectin Demethylesterification Generates Platforms that Anchor Peroxidases to Remodel Plant Cell Wall Domains

• Published in: Developmental cell 2019-01, Vol.48 (2), p.261-276.e8
• Main Authors: Francoz, Edith, Ranocha, Philippe, Le Ru, Aurélie, Martinez, Yves, Fourquaux, Isabelle, Jauneau, Alain, Dunand, Christophe, Burlat, Vincent
• Format: Article
• Language: English
• Subjects: Arabidopsis - metabolism; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Biochemistry, Molecular Biology; Botanics; Cell Wall - drug effects; Cell Wall - metabolism; class III peroxidase; FRET-FLIM immunofluorescence; Gene Expression Regulation, Plant - drug effects; homogalacturonan methylesterification; Life Sciences; Molecular biology; Mutation - drug effects; pectin methylesterase inhibitor; Pectins; Peroxidases - drug effects; plant cell wall domain; Plant Extracts - pharmacology; PMEI6; protein-polysaccharide interaction; PRX36; seed mucilage secretory cells; Seeds - growth & development; Vegetal Biology
• ISSN: 1534-5807; 1878-1551
• DOI: 10.1016/j.devcel.2018.11.016

Plant cell walls are made of polysaccharidic-proteinaceous complex matrices. Molecular interactions governing their organization remain understudied. We take advantage of the highly dynamic cell walls of Arabidopsis seed mucilage secretory cells to propose a hierarchical multi-molecular interaction model within a cell wall domain. We show that the PECTINMETHYLESTERASE INHIBITOR6 activity creates a partially demethylesterified pectin pattern acting as a platform allowing positioning of PEROXIDASE36 in a remote primary cell wall domain during early development. This allows triggering the loosening of this domain during later development, in turn leading to proper physiological function upon mature seed imbibition and germination. We anticipate that this pioneer example of molecular scaffold within a cell wall domain is more widespread through other combinations of the individual molecular players all belonging to large multigenic families. These results highlight the role of cell wall polysaccharide-protein interactions in the organization of cell wall domains. [Display omitted] •Remodeling of plant cell wall domains necessitates wall-polarized molecular scaffolds•PMEI6 creates a partially demethylesterified pectin platform in a cell wall domain•PRX36 is anchored to this pectin platform during early seed development•PRX36 loosens the wall domain during late seed development for dry seed functions During Arabidopsis seed development, local loosening of a primary wall domain is necessary for proper function later during dry seed imbibition. Francoz et al. uncover molecular players governing local remodeling of this wall domain. Plant development may implicate similar molecular scaffolds with other members of the involved multi-gene families.