Distribution of tobacco rattle virus in tubers of resistant and susceptible potatoes and systemic movement of virus into daughter plants

Fifty-nine potato cultivars or breeding clones were planted near Umatilla, OR and/or Pasco, WA, in fields known to be infested with tobacco rattle virus (TRV) and vector nematodes, Paratrichodorus allius Jen. (Sid.). Tubers from these field plots were cut and examined for corky ringspot (CRS) symptoms, Reverse transcription-polymerase chain reaction (RT-PCR) for TRV was conducted on tissue samples from symptomatic and asymptomatic tubers. Sixty-five percent of the symptomatic and 42% of the asymptomatic tissue samples from CRS symptomatic tubers contained detectable TRV. Approximately 2% of plants grown from either symptomatic or asymptomatic tubers contained TRV when tested by ELISA, whereas 20% and 12% of plants grown from symptomatic and asymptomatic tubers, respectively, were positive for TRV by RT-PCR. These results suggest that RT-PCR is a more sensitive assay for detection of TRV. Systemic infections by TRV were detected more often in foliage of CRS-susceptible genotypes. Daughter tubers exhibiting symptoms of CRS, and which contained RT-PCR-detectable TRV, were produced on plants of three genotypes, including one from an asymptomatic parent tuber.