DETECTION AND IDENTIFICATION OF YELLOW MOSAIC STUNT DISEASE ON Petunia sp. USING NESTED PCR METHOD

Yellow mosaic stunt disease was found at some nurseries of Petunia in Sleman, Yogyakarta, also in Muntilan and Magelang Central Java. The disease was very important due to its ability reducing the quality and quantity of Petunia seedlings. The causal agent of the disease may be carried over to imported seeds and necessary to identify as a basic information for developing control strategies. This research was done by mechanical transmission on indicator plants. The observation of the causal agents was conducted using electron microscope with quick dipping method and the molecular detection was done using nested PCR with TobRT up1-TobRT do2 as the external primers and TobN up3-TobN do4 as the internal primers. Mechanical inoculation showed chlorosis symptoms that developed into local spot on Chenopodium amaranticolor as well as mosaic and vein banding on Nicotiana benthamiana. The observation using electron microscope showed rod-shaped virus particles sized approximately 300 nm and by PCR method produced around 568 bp and 400 bp DNA band. Based on the sequence analysis, the disease was caused by Rehmania mosaic virus. This type of Tobamovirus has 96% similarity with ReMV-Japan. ReMV, a plant pathogen which was a member of Tobamovirus that has never been reported in Indonesia. This research was the first report of ReMV in Indonesia infecting Petunia as ornamental plant.