VUNSH, R., Department of Virology, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
ROSNER, A., Department of Virology, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
STEIN, A., Department of Virology, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel

A method is described for the improved detection of bean yellow mosaic virus (BYMV) in gladioli leaves. Specific sequences of BYMV RNA, present in total RNA extracts of infected plants were detected following amplification by the polymerase chain reaction (PCR). The viral RNA was initially reverse‐transcribed into cDNA, then specific sequences were amplified by PCR using specific oligonucleotides as primers. Detectable amounts of virus RNA in BYMV‐infected plant tissue by PCR were approximately three to four orders of magnitude lower as compared with those detectable by ELISA and molecular hybridisation. Combining PCR with molecular hybridisation (using a 32P‐labelled transcript of viral sequences as a probe), further increased the sensitivity of this method to a gain of four to five orders of magnitude as compared with direct molecular hybridisation, and enabled the detection of up to single picogram quantities of the virus. Copyright © 1990, Wiley Blackwell. All rights reserved