DETECTION OF POTATO LEAFROLL AND STRAWBERRY MILD YELLOW-EDGE LUTEOVIRUSES BY REVERSE TRANSCRIPTION-POLYMERASE CHAIN-REACTION AMPLIFICATION

DNA primers were constructed based on the nucleotide sequence of the c oat protein gene of potato leafroll luteovirus (PLRV) and utilized for cDNA synthesis and polymerase chain reaction (PCR) amplification of a 487-bp DNA fragment from nucleic acid extracts of PLRV-infected tissu e, and an approximately 500-bp DNA fragment from the luteovirus associ ated with strawberry mild yellow-edge-infected tissue. The amplified D NA fragments were identified by hybridization analysis with a cDNA pro be for the coat protein gene of PLRV and differentiated by restriction fragment length polymorphism analysis. Reverse transcription (RT)-PCR assays were developed for the detection of PLRV in nucleic acid extra cts of infected potato leaves and tubers, and in viruliferous aphids. The luteovirus-specific DNA was absent from amplified extracts of unin fected potato or nonviruliferous aphids. The RT-PCR assay for PLRV is more sensitive than existing detection methods and detects PLRV in pla nt hosts or insect vectors without requiring large samples or molecula r hybridization.