Detection of Sweet Potato Virus Disease-Associated Closterovirus in a Sweet Potato Accession in the United States

A closterovirus (sweet potato virus disease-associated closterovirus [SPVD-aC]) that, in association with sweet potato feathery mottle potyvirus (SPFMV), causes the Nigerian sweet potato virus disease (SPVD), was detected in sweet potato (Ipomoea setosa) following grafting of infected scions of sweet potato cv. White Bunch, an accession in the USDA sweet potato repository. Confirmation of infection with SPVD-aC was by a riboprobe hybridization assay specific for the viral RNA coupled with chemiluminescent detection of the bound RNA, and SPFMV was detected by enzyme-linked immunosorbent assay (ELISA) using a specific antiserum. This is the first report of SPVD-aC and of SPVD in sweet potato in North America. Use of the riboprobe hybridization assay should facilitate a more rapid detection of SPVD-aC infected sweet potato and subsequent selection of virus-free germ plasm for international exchange.