Abstract:
Rice ragged stunt virus (RRSV)-Bangkok isolate was inoculated into Taichung Native 1 (TN 1) rice variety by brown planthoppers (Nilaparvata lugens Stal.) for study the detection of RRSV infected in wild rice, lowland rice and upland rice varieties. The S4F/S4R primers were designed for the detection of RRSV based on nucleotide sequences of the ORF2 gene in genome segment 4 of RRSV (GanBank no. U 66714). A One Step Reverse Transcription-Polymerase Chain Reaction (One Step RT-PCR) was applied for the detection of RRSV. The amplified product of approximately 970-bp was obtained from all infected samples using S4F/S4R primers. The amplified product from RT-PCR was shown to be part of ORF2 gene in genome segment 4 of RRSV by sequence analysis. It has high similarity (99 percent) with RRSV in GenBank no. U66714 in nucleotide sequences. The sequence of Bangkok isolate from this study has been submitted to National Center of Biotechnology Informatics (NCBI) database with the accession no. AF 390545. The sensitivity of the RRSV detection using RNAs isolated from infected plants by two different RNA extraction methods was compared. The PCI extraction method was more sensitive than the RNeasy Plant Mini Kit (QIAGEN). The virus can be detected in most of plant parts including leaf, leaf sheath, stern and root and in a single viruliferous brown planthopper. The RT-PCR can be effectively detected RRSV in infected wild rice, lowland rice and upland rice, either with or without symptom expression.