We have shown previously that a gene encoding a homologue to the eukaryotic dolichol-phosphate-D-mannose, protein O-D-mannosyltransferase, was required for (phi)C31 infection of Streptomyces coelicolor. Here we show that a gene encoding the homologue to dolichol-phosphate-mannose synthase is also essential for phage sensitivity. These data confirm the role of glycosylation in the phage receptor for (phi)C31 in S. coelicolor.