DETECTION OF PRUNUS NECROTIC RINGSPOT VIRUS SEROTYPES IN HERBACEOUS AND PRUNUS HOSTS WITH A COMPLEMENTARY RNA PROBE

Complementary DNAs (cDNAs) prepared from genomic RNA of a peach isolate of Prunus necrotic ringspot virus (PNRSV) were used to produce a P-32-labeled complementary RNA (cRNA) probe that was capable of detecting PNRSV in tissue extracts. RNA transcripts of an 800 bp cDNA fragment inserted into plasmid pGEM-7Zf(+) were obtained using SP6 and T7 RNA polymerases. Dot-blot hybridizations using radiolabeled SP6 transcripts were compared to enzyme-linked immunosorbent assay (ELISA) for the detection of PNRSV serotypes in peach, cherry, and herbaceous hosts. In most tissues the limits of detection of PNRSV were similar with ELISA and cRNA hybridization. However, PNRSV serotype CH30 reacted poorly in ELISA but was readily detected by the cRNA probe. The probe did not detect prune dwarf, apple mosaic, or tobacco streak ilarviruses or a virus isolated from hops previously considered to be PNRSV.