IDENTIFIKASI MOLEKULER CUCUMBER MOSAIC VIRUS (CMV) ASAL TANAMAN NILAM (Pogostemon cablin) / Molecular Identification of Cucumber Mosaic Virus Infecting Patchouli (Pogostemon cablin)

Mosaic disease on Indonesian patchouli associated with infection of TeMV, BBWV2, CymMV and CMV. TeMV, BBWV2 and CymMV has been identified molecularly, while CMV just was detected serologically. The objective of this study was to identify CMV from patchouli by molecular approach based on CP gene nucleotide sequence Leaf samples were collected from three mosaic symptomatic patchouli plants in greenhouse of Balittro. Leaf samples were extracted for the total nucleic acids (RNA + DNA). Nucleic acids were amplified using specific primer for CP gene of CMV by one step RT-PCR technique. The DNA of PCR product with the size of ~ 650 bp was directly sequenced and analyzed for its homology with sequences of CMV isolates extracted from Gene Bank. CMV CP gene from patchouli showed the highest of nucleotide and amino acid sequence similarities, 97,1 and 97,7% respectively, with um Japanese isolates. Phylogenetic tree analysis revealed that CMV from patchouli was closely related with um-Japanese isolate with 100% bootstrap value, and clustered with another CMV isolates in subgroup IB. Since the CMV subgroup I was more virulent than subgroup, it is necessary to increase the awareness of the CMV occurrence in another plant. Key words : homology analysis, phylogeny tree, nucleotides, amino acid Abstrak Penyakit mosaik pada tanaman nilam di Indonesia berasosiasi dengan infeksi Telosma mosaic virus (TeMV), Broad bean wilt virus 2 (BBWV2), Cymbidium mosaic virus (CymMV) dan Cucumber mosaic virus (CMV). TeMV, BBWV2 dan CymMV sudah diidentifikasi secara molekuler, sedangkan CMV baru terdeteksi secara serologi. Karakte risasi molekuler setiap virus diperlukan sebagai salah satu dasar pengambilan tindakan pengendalian. Penelitian ini bertujuan untuk mengidentifikasi CMV asal tanaman nilam secara molekuler berdasarkan sekuen nukleotida gen CP. Tiga sampel daun nilam bergejala terinfeksi virus diambil dari koleksi tanaman nilam di rumah kaca Balittro. Sampel daun diekstraksi asam nukleat totalnya (RNA+DNA). Asam nukleat total diamplifikasi dengan teknik one step reverse transcriptase polymerase chain reaction (RT-CR) menggunakan primer spesifik gen coat protein (CP) CMV. Produk PCR berukuran 650 pb (pasang basa) dirunut sekuen nukleotidanya serta dianalisis homologi dan hubungan filogenetikanya dengan sekuen isolat-isolat CMV yang ada di GenBank. Sekuen nukleotida dan asam amino gen CP CMV asal nilam menunjukkan persentase kemiripan terbesar (97,1 dan 97,7%) dengan isolat um -Jepang. Analisis filogeni menunjukkan bahwa CMV asal nilam berkerabat sangat dekat dengan CMV isolat um-Jepang dengan nilai bootstrap 100%, dan berada dalam satu kelompok dengan isolat-isolat CMV subgrup IB. Keberadaan CMV subgrup IB pada tanaman nilam perlu diwaspadai karena subgrup I lebih virulen dibandingkan subgrup II. Penelitian ini merupakan laporan pertama karakterisasi molekuler CMV nilam, baik di Indonesia maupun di luar negeri, yang dapat digunakan sebagai salah satu dasar pengambilan tindakan pengendalian. Kata kunci: analisis homologi, pohon filogeni, nukleotida, asam amino