RNA sequences complementary to citrus exocortis viroid in nucleic acid preparations from infected Gynura aurantiaca.

Molecular hybridization with (125)I-labeled citrus exocortis viroid RNA has been used to survey nucleic acid preparations from Gynura aurantiaca for viroid complementary molecules. A differential hybridization effect was detected between nucleic acid extracts from healthy and infected tissue in which significant RNase-resistant (125)I-labeled citrus exocortis viroid resulted in hybridization studies with the infected tissue extracts. Subsequent characterization indicated that RNA from infected tissue was involved in the formation of a duplex molecule with citrus exocortis viroid RNA and had properties of an RNA.RNA hybrid. Subcellular fractionation of infected tissue indicates that the complementary RNA is present in nuclear and soluble RNA fractions. This RNA may represent an intermediate molecule in the replication of the viroid or a pathogenic expression and may have a regulatory role in the host cell.