Judul: Efisiensi penularan virus mosaik bengkuang (Bean common mosaik virus-BCMV isolat Lybn) dengan APhis craccivora Koch. dan A. gossypii Glover
Abstrak: Penelitian ini dilaksanakan pada bulan Oktober sampai Desember 2009 di rumah kaca Cikabayan dan Laboratorium Virologi Tumbuhan, Departemen Proteksi Tanaman, Institut Pertanian Bogor. Tujuan penelitian ini adalah mengetahui efisiensi penularan virus mosaik bengkuang (VMB) oleh Aphis craccivora Koch. dan A. gossypii Glover. Efisiensi penularan VMB dengan A. craccivora dan A. gossypii dilakukan dengan cara menularkan virus ke tanaman bengkuang sehat dengan jumlah kutudaun masing-masing 1, 3, 5, 7, dan 10 ekor secara non-persisten. Inokulasi dilakukan pada saat umur tanaman 2 minggu setelah tanam (MST). Periode makan akuisisi selama dua jam dan periode makan inokulasi selama 24 jam. Kontrol hanya diinokulasi oleh kutudaun yang tidak mengandung virus. Percobaan diulang sebanyak 10 kali pada setiap perlakuan jumlah kutudaun. Peubah yang diamati adalah masa inkubasi, tipe gejala, dan kejadian penyakit. Deteksi virus dengan uji serologi ELISA dilakukan hanya pada tanaman bengkuang yang tidak menampakkan gejala untuk mengkonfirmasi kejadian penyakit. Data dianalisis dengan ANOVA dan uji selang berganda Duncan pada taraf 95%. Hasil penularan virus dengan kedua spesies kutudaun pada perlakuan jumlah kutudaun satu ekor sudah cukup efisien untuk menularkan VMB. Pada penularan dengan A. craccivora ada perbedaan masa inkubasi antara satu ekor dengan 3, 5, 7, dan 10 ekor, sedangkan masa inkubasi penularan dengan A. gossypii menunjukkan masa inkubasi yang lebih panjang untuk tiap perlakuan dibandingkan penularan dengan A. craccivora. Selain itu perlakuan dengan A. gossypii tidak menunjukkan perbedaan yang nyata antar perlakuan. Berdasarkan hasil penelitian ini diketahui bahwa A. craccivora lebih efisien sebagai vektor virus VMB dibandingkan dengan A. gossypii. Tipe gejala VMB hasil penularan dengan A. craccivora dan A. gossypii ada tiga yaitu mosaik, malformasi daun, dan vein banding. Tipe gejala yang ditimbulkan oleh A. craccivora adalah mosaik dan malformasi daun yang parah dengan bentuk daun mengecil dan memanjang menyerupai tali, sedangkan tipe gejala hasil penularan dengan A. gossypii adalah malformasi daun dengan permukaan daun berkerut dan bergelembung. Kejadian penyakit pada A. gossypii dan A. craccivora berturut-turut sebesar 70-100% dan 90-100%.
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Judul: Keragaman, Kisaran Inang dan Efisiensi Penularan Bean common mosaic virus dengan Kutudaun pada Tanaman Kacang Panjang
Abstrak: Bean common mosaic virus (BCMV) is one of the important viruses infecting yard long beans. Severe yellow mosaic symptoms different from common symptoms of BCMV was observed in 2008 in several yard long bean growing areas in West Java and Central Java found. This severe yellow mosaic symptom is caused by Bean common mosaic virus Blackeye Cowpea strain (BCMV-BlC) or double infection of BCMV-BlC and Cucumber mosaic virus (CMV). Information on characters of BCMV-BlC on yard long beans in Indonesia is very limited, despite its importance for the determination of virus control strategy. Therefore this study aims to determine the diversity, host range and transmission efficiency of BCMV-BlC using 3 aphid species . Leaf samples showing yellow mosaic symptoms were taken from yard long bean plants in 3 villages in Dramaga, Bogor, West Java i.e. Bubulak, Cangkurawok, and Situgede and 10 leaf samples from several areas in West Java [Bogor (Bojong), Subang, Indramayu and Cirebon], and Central Java (Tegal, Klaten, Solo, Magelang, Sleman, and Jogjakarta) collection of Plant Virology Laboratory, Department of Plant Protection, Faculty of Agriculture, IPB. Leaf samples were detected by serological using antiserum of BCMV and molecular method using specific primer for BCMV coat protein (CP). Amplified DNA products was then used for nucleotide sequencing followed by sequence allignment and phylogenetic tree analysis. Limited host range study and transmission of BCMV-BlC using three species of aphids was done for BCMV-BlC Cangkurawok isolates. BCMV-BlC isolated by inoculation on indicator plants Chenopodium amaranticolor. Local lesions (LL) were taken and inoculated serially to C. amaranticolor for 3 times to purify the virus. Finally, LL was inoculated on bean cultivar Parade and used as sources of inoculum for further test. A host range study was conducted by inoculating BCMV-BlC mechanically using 18 plant species from 3 families. Transmission efficiency test was done using 3 aphid species i.e. Aphis craccivora Koch, A. gossypii Glover and A. glycines Matsumura with treatment of aphids numbers (1, 3, 5, 7 and 10). Both host range and transmission efficiency studies was conduxted using 15 plants per treatment. Parameter for both studies includes incubation period, type of symptoms and disease incidence. In addition to visual observation, infection of BCMV-BlC on test plants was confirmed by using Dot Immunobinding Assay (DIBA). Based on field observations, the symptoms can be differentiated into 2 groups. The first group consist of those symptoms showing mosaic with light green to bright yellow unevenly (heavy yellow mosaic), vein banding, malformation of leaves (leaf curl like crackers, pucker along the veins), leaf blister, and stunted growth. The second group are those symptoms showing mosaic pattern of light green to yellow (medium yellow mosaic) and vein banding. Molecular detection by RT-PCR are successfully amplified ~861 bp viral DNA from 8 out of 13 BCMV isolates. DNA analysis was able to allign sequence of BCMV collected from Cangkurawok, Cirebon, Subang, Tegal, Solo and Sleman, but was unable to allign the sequence of BCMV isolates from Bubulak and Bojong. Further analysis showed that 4 BCMV isolates (Cangkurawok, Subang, Solo and Sleman) has the highest homology to BCMV-BlC from Taiwan,
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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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