Involved in the biosynthesis of sterol glucosides. Catalyzes the synthesis of steryl glycosides (SGs) and acyl steryl glycosides (ASGs) which are the most abundant sterol derivatives in higher plants. Can act on several sterols like sitosterol, campesterol and stigmasterol. Both UGT80A2 and UGT80B1 are required for the normal production of SGs and ASGs in seeds. a sterol + UDP-alpha-D-glucose = a sterol 3-beta-D-glucoside + H(+) + UDP Expressed in roots, cauline leaf epidermal cells, stomata, stamen, pollen and around the base of siliques. Reduced growth rates. Belongs to the glycosyltransferase 28 family. Truncated N-terminus.