Detection and characterization of defective interfering RNAs associated with the cocksfoot mottle sobemovirus

A new RNA of about 900 nt was found in the virions of cocksfoot mottle viru s (CfMV) and in infected plants by RNA hybridization and RT-PCR. Structural features suggested that this RNA is a defective interfering RNA (diRNA). T he CfMV diRNA was shown to consist of a 35-nt 5'-terminal genomic region, w hich formed a hairpin, and a 3'-terminal genomic region, which included the coat protein (CP) gene lacking the first 120 nt. In vitro translation of t he diRNA started at the third Met codon to produce truncated CP. The CfMV d iRNA was assumed to trans-activate synthesis of the CP subgenomic RNA (sgRN A).