Judul: Telosma mosaic virus associated with mosaic disease of patchouli plant: identification and control approach
Abstrak: Patchouli oil (patchouli alcohol) produced by patchouli plant (Pogostemon cablin Benth.) is one of the raw materials of high value multifunctional perfume. However, in the process of cultivation and development of this commodities are attacked by plant pest organisms, especially diseases. Some important diseases of patchouli, which is now spread in Indonesia, namely budok, bacterial wilt, diseases caused by nematodes and viruses. This study aimed (1) to map the presence of mosaic disease on patchouli plantation in patchouli production centers of Indonesia, (2) to measure product reduction of patchouli plants due to mosaic disease, (3) to identify viruses associated with mosaic disease, (4) to identify aphid species found colonizing patchouli plants in the field, (5) to molecularly characterize viruses associated with mosaic disease on patchouli, (6) to analyze the genetic diversity among Telosma mosaic virus (TeMV) isolated from patchouli, (7) to determine the host range of TeMV, (8) to determine the relationship of the aphids colonizing patchouli plants with mosaic disease, and (9) to obtain virus-free patchouli seedling by apical meristem culture method and hot water treatment. The results show that the mosaic disease was found in all patchouli production areas of Java and Sumatra and two species of aphids, i.e. Aphis gossypii Glover and Brachycaudus sp. were found colonizing patchouli plants in all survey locations. Due to the mosaic disease, reduction of fresh herbs weight, dry herbs weight, oil content and the patchouli alcohol of patchouli in the first harvest was reached 35%, 40%, 9% and 5%, respectively. Based on the serological test, Potyvirus was found predominantly associated with the mosaic symptoms. Further identification based on nucleotide sequence of coat protein gene revealed that the species of Potyvirus is Telosma mosaic virus (TeMV). Host range and aphid transmission evaluation confirmed the association of Potyvirus with mosaic disease. This paper is the first report of occurence of TeMV in Indonesia. This virus will be easily to spread to any areas because patchouli plants are propagated by stem cuttings. In this study, a technique was also developed to produce virus-free cutting using apical meristem culture and hot water treatment on stem cutting. The patchouli plant has been propagated from apical meristem culture of 0.5-1 mm in sizes yielded 33.3-90.9% virus-free plants. Submersion of patchouli stem cutting in hot water of 50-60⁰C for 10-30 minutes could not eliminated TeMV. Apical meristem culture technique is potential to produce virus-free cutting of patchouli.
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Judul: Identifikasi Telosma mosaic virus Penyebab Penyakit Mosaik pada Tanaman Nilam (Pogostemon cablin Benth.)
Abstrak: Nilam (Pogostemon cablin Benth.) adalah satu dari sekian banyak tanaman penting yang digunakan untuk minyak esensial sebagai material dasar pada industri yang berbeda. Tanaman nilam terinfeksi oleh virus yang menyebabkan penyakit pada daun dengan gejala mosaik ditemukan di daerah Bogor, Jawa Barat. Setelah dideteksi melalui enzyme-linked immunosorbent assay (ELISA) menggunakan antiserum terhadap Broad bean wilt virus, Cucumber mosaic virus, Tobacco mosaic virus, dan Potyvirus terlihat bahwa sampel tanaman nilam bergejala mosaik tersebut bereaksi kuat terhadap antiserum Potyvirus dan tidak terhadap antiserum lainnya. Oleh karena itu, identifikasi terfokus pada Potyvirus. Reverse transcription-polymerase chain reaction (RT-PCR) menggunakan primer spesifik untuk genus Potyvirus berhasil mengamplifikasi RNA genom virus pada gen coat proteinnya. Analisis sikuen nukleotida pada produk RT-PCR mengindikasikan bahwa virus tersebut adalah Potyvirus seperti yang telah dilaporkan sebelumnya. Berdasarkan homologi sikuen nukleotida, Potyvirus tersebut terindentifikasi sebagai Telosma mosaic virus (TeMV). Penelitian ini merupakan laporan pertama infeksi TeMV pada tanaman nilam di Indonesia.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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