Evaluation of NASH and RT-PCR for the detection of PVY in dormant tubers and its comparison with visual symptoms and ELISA in plants

Abstract

Detection of the common strain of PVY (PVYO) in field-grown dormant potato tubers, by nucleic acid spot hybridization (NASH) and reverse-transcription polymerase chain reaction (RT-PCR) was compared with diagnosis by visual symptoms and enzyme linked immunosorbent assay (ELISA) on leaves of eight potato cultivars, differing in their symptom expression and virus content. NASH and RT-PCR readily detected PVYO in dormant tubers. The percent agreement between NASH and RT-PCR ranged from 77.6 to 100 for cvs. included in this study (AC Novachip, Atlantic, Norchip, Red Pontiac, Russet Burbank, Russet Norkotah, Shepody and Superior). ELISA on leaves was almost as good as NASH and RT-PCR on dormant tubers, but required dormancy break. Only two cultivars, namely Red Pontiac and Russet Burbank, could accurately be assessed, based on the visual symptoms. A very high degree of discrepancy was observed for PVYO diagnosis between visual symptoms and other detection procedures for varieties like Russet Norkotah and Shepody, which are known to be latent carriers of PVYO. The use of NASH and RT-PCR in large-scale post-harvest testing is feasible.