Improved Detection of Potato Leafroll Luteovirus in Leaves and Tubers with a Digoxigenin-Labeled cRNA Probe.

A digoxigenin-labeled cRNA probe of approximately 2,100 bp was more than 2,000 times more sensitive in detecting potato leafroll virus (PLRV) in leaf extracts of Datura stramonium, Physalis floridana, and potatoes than enzyme-linked immunosorbent assay (ELISA). The limit of detecting PLRV with the probe was 1 pg/ml compared with 2 ng/ml by ELISA. The probe detected PLRV easily in dormant tuber tissues at dilutions of up to 1:100. There was no background reaction with healthy extracts. No reactions were observed between the probe and potato X potexvirus or potato Y potyvirus.