Detection of beet necrotic yellow vein virus using reverse transcription and polymerase chain reaction.

A diagnostic test based on reverse transcription followed by the polymerase chain reaction (RT-PCR) was developed for the detection of beet necrotic yellow vein virus (BNYVV). A specific 500-base-pair fragment was amplified from the read-through region of the coat protein gene located on RNA-2. The viral origin of the amplified product was confirmed by sequencing, with the sequence obtained having 94.5% homology with published sequence data for BNYVV. The assay gave a sensitivity of 800 times that of a TAS-ELISA and 50 times that of an amplified TAS-ELISA method. A range of BNYVV isolates from the UK and worldwide could be detected by this test, either as mechanically inoculated Chenopodium quinoa leaves or infected sugar beet roots. Use of the assay in routine diagnostic tests allowed a reduction of time needed for the detection of Rhizomania in soils from 7 to 4 weeks.