Xyloglucan-specific galacturonosyltransferase that forms the beta-D-galactosyluronic acid-(1->2)-alpha-D-xylosyl linkage. Required for root hair development probably by providing important acidic xyloglucans. Root hair specific (PubMed:19448035, PubMed:22253603). Expressed in roots and young leaves (PubMed:15020758). Lacks acidic xyloglucan and has short root hairs. Belongs to the glycosyltransferase 47 family.