TRANSCRIPTION AMPLIFICATION OF POLYMERASE CHAIN-REACTION PRODUCTS OF BEAN YELLOW MOSAIC-VIRUS RNA EXTRACTED FROM GLADIOLI CORMS

The RNA genome of bean yellow mosaic virus (BYMV) was detected in glad ioli corms by reverse transcription and polymerase chain reaction (PCR ). However, a positive signal was not obtained from some infected corm s because the virus concentration was below the sensitivity limits of PCR. Virus was detected in these corms by using a modified protocol in which transcription of the PCR products by T7 RNA polymerase yielded an additional 10- to 100-fold signal amplification. The relative conce ntrations of BYMV in gladioli corms were evaluated using PCR. Virus ac cumulation in corms was found to be a 100 times lower than in leaves, and be within the range of picogram quantities of viral RNA per gram f resh weight of corm tissue.