Rapid Detection of Tobacco Rattle Tobravirus in Viruliferous Paratrichodorus allius from Greenhouse and Field Specimens.

The stubby root nematode, Paratrichodorus allius, is important to the potato industry in the Pacific Northwest of USA, because it vectors Tobacco rattle virus (TRV), the causal agent of corky ringspot disease. The current method for determining if nematodes are viruliferous for TRV takes several weeks, requiring a glasshouse bioassay followed by a serological test. To overcome this drawback, a rapid and affordable molecular test was developed using reverse transcription polymerase chain reaction (RT-PCR) to identify viruliferous P. allius nematodes within 48 hours. Primers from the 16 kDa gene of TRV were used to detect TRV in both greenhouse-reared and field collected P. allius. TRV RNA can be detected consistently in nucleic acids equivalent to one quarter of a viruliferous adult nematode reared in the greenhouse. In order to reduce the time and expense of processing individual nematodes from field samples, viral RNA was consistently and affordably detected in extracts from 5 field-collected adult P. allius.