Abstract
Family 1 glycosyltransferases, often referred to as UDP glycosyltransferases (UGTs), catalyze the transfer of sugar moieties to a wide range of acceptor molecules including plant secondary metabolites.
To address how UGTs expanded both in number and function during the evolution of land plants, we screened genome sequences from six plants (Physcomitrella patens, Selaginella moellendorffii, Populus trichocarpa, Oryza sativa, Arabidopsis thaliana and A. lyrata) for a conserved UGT protein domain. Phylogenetic analyses of the UGT genes revealed a significant expansion of UGTs with lineage-specificity and a higher duplication rate in vascular plants after the divergence of Physcomitrella. The UGTs from the six species fell into 24 orthologous groups that contained genes derived from the common ancestor of these six species. Some orthologous groups contained multiple UGT families with known functions, suggesting that UGTs had discriminated compounds as a substrate in a lineage-specific manner. Orthologous groups with only a single UGT family tend to play a crucial role in plants, suggesting that such UGT families might not be expanded because of evolutionary constraints.
