Probable glycosyltransferase involved in the O-arabinosylation of several proteins including extensins and small signaling peptides (By similarity). Catalyzes the transfer of the initial L-arabinose to the hydroxyl group of Hyp residues (By similarity). Probably involved in the arabinosylation of CLAVATA3/ESR-related (CLE) signaling peptides that move from root to shoot, to interact with receptor kinase signaling that regulates nodulation (By similarity). Involved in long distance nodulation signaling events (PubMed:21742814, PubMed:21802605). Involved in the autoregulation of nodulation (AON), a long distance systemic signaling from root to shoot and back again, which allows legumes to limit the number of root nodules formed based on available nitrogen and previous rhizobial colonization (PubMed:21742814, PubMed:21802605). trans-4-hydroxy-L-prolyl-[protein] + UDP-beta-L-arabinofuranose = H(+) + O-(beta-L-arabinofuranosyl)-trans-4-hydroxy-L-prolyl-[protein] + UDP Dramatic increase in root nodule number when inoculated with Rhizobium strains (PubMed:21742814, PubMed:21802605). Inhibition of root growth in both the presence and absence of rhizobia (PubMed:21742814, PubMed:21802605). Belongs to the RDN family.