Expressing microbial polysaccharide-modifying enzymes in plants is an attractive approach to custom tailor plant lignocellulose and to study the importance of wall structures to plant development. Expression of α-glucuronidases in plants to modify the structures of glucuronoxylans has not been yet attempted. | Active fungal GH115 α-glucuronidase produced in Arabidopsis thaliana affects only the UX1-reactive glucuronate decorations on native glucuronoxylans