No abstract

Conventional PCR is a reliable method for detecting SCSMV. The availability of quantitative PCR (qPCR) can increase the power of PCR as detection method due to its high sensitivity and ability to quantify the template DNA in the reaction mixture. The study was aimed to validate the qPCR method for detection of SCSMV, and to develop detection methods for virus indexing program in seed canes production. qPCR method developed in this study was relative-qPCR with the regression equation of Y = -7,255 * log X + 11.752 for the SCSMV standard curve, so the value of X = 10 (-0.138 * Ct + 1,620). Ct value is inversely proportional to the concentration of cDNA. The greater the Ct value, the lower the concentration of cDNA in the sample. It was proved that qPCR method is more sensitive compared to conventional PCR, because it was able to detect SCSMV in samples not detected by conventional PCR methods. The relation between the Ct value and the incidence and severity of the disease on the field was assessed using field samples for qPCR. It was shown that Ct value and virus concentration did not have relation to the incidence and severity of the disease in the fields.

Salah satu upaya untuk meningkatkan produksi gula dalam negeri adalah melalui perluasan daerah penanaman tebu ke luar Pulau Jawa. Status penyakit tebu di luar Pulau Jawa, terutama yang disebabkan oleh virus, belum banyak diketahui, padahal infeksi virus dapat menurunkan produktivitas tanaman. Penelitian dilakukan untuk mengetahui sebaran penyakit dan jenis virus utama pada tanaman tebu di Lampung dan Sulawesi Selatan. Survei dan pengambilan sampel tanaman dilakukan di Kabupaten Lampung Tengah, Provinsi Lampung dan tiga kabupaten di Provinsi Sulawesi Selatan, yaitu Kabupaten Bone, Gowa, dan Takalar. Deteksi sampel dilakukan dengan metode reverse transcription-polymerase chain reaction (RT-PCR) menggunakan primer spesifik untuk Sugarcane mosaic virus (SCMV), Sugarcane streak mosaic virus (SCSMV), dan Sugarcane yellow leaf virus (SCYLV). Tanaman tebu di lapangan menunjukkan gejala infeksi virus yang bervariasi. Insidensi dan keparahan penyakit tertinggi terjadi di Lampung, yaitu berturut-turut sebesar 100% dan 61,6771,67%; sedangkan insidensi dan keparahan penyakit terendah terjadi di Takalar, yaitu berturut-turut sebesar 570% dan 545%. Berdasarkan hasil RT-PCR diperoleh hasil bahwa infeksi SCMV dan SCSMV ditemukan di semua wilayah pengamatan, sedangkan infeksi SCYLV hanya ditemukan di Bone dan Lampung Tengah dan hanya terdeteksinya SCYLV merupakan laporan pertama di Indonesia. Insidensi dan keparahan penyakit virus tebu rendah pada kondisi lingkungan kering dan curah hujan yang rendah. Informasi ini diharapkan dapat bermanfaat dalam program ekstensifikasi pengembangan perkebunan tebu dalam mendukung program swasembada gula.

Detection of plant viruses can be done by protein or nucleic acid approaches. The immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) method is a combination of the two approaches. Research was carried out to develop and validate IC-RT- PCR based-detection method for SCSMV, which can be applied for the sugarcane seed indexing program to support the national government’s goal for sugar self-sufficiency. Evaluation of the IC-RT-PCR method was conducted using 5 field samples. Conventional PCR and serological methods, i.e. dot immunobinding assay (DIBA) and enzyme-linked immunosorbent assay (ELISA) was also performed in the same time. All field samples gave a positive reaction to SCSMV antibodies in the DIBA and ELISA methods with the intensity of the reaction varying from low to high. SCSMV was still detected on plant extract up to 104 dilution by ELISA and DIBA. Specific DNA fragments were successfully amplified from 2 field samples using the conventional PCR method; whereas the IC-RT-PCR method was successfully amplified all field samples. Optimization test showed that the IC-RT-PCR method was able to detect SCSMV from plant extract up to 10−10 dilutions. IC-RT-PCR method is more sensitive than conventional PCR and might be recommended for the indexing method to produce high-quality virus-free sugarcane seed.