May be involved in the synthesis of homogalacturonan. Required for normal cell adhesion and plant development. Glycan metabolism; pectin biosynthesis. Ubiquitous. Deformed dwarf phenotype and reduced cell adhesion. Hypersensitive to imbalanced C:N ratio. Co-expressed with the galacturonosyltransferase GAUT8/QUASIMODO1. Belongs to the methyltransferase superfamily.