Judul: Deteksi dan identifikasi pineapple mealybug wiltassociated virus penyebab penyakit layu pada tanaman nanas di Indonesia
Abstrak: Field surveys on pineapple wilt disease were conducted on pineapple production areas in Subang, West Java, Indonesia. The disease was characterized by severe tip dieback, downward curling, reddening, and wilting of the leaves which can lead to total collapse of the plant. The objective of the research is to identify the viruses causing wilt disease on pineapple in Indonesia. Tissue blot immunoassays (TBIAs) using two different antibodies specific to either Pineapple mealybug wilt-associated virus-1 (PMWaV-1) or PMWaV-2 (Agdia Inc., USA) successfully detected the viruses in leaf tissues from both symptomatic and asymptomatic pineapple plants. A reverse transcription-polymerase chain reaction (RT-PCR) assays using oligonucleotide primers specific to HSP 70 gene of PMWaV-1 and PMWaV-2 were also successfully amplified the regions succesfully. These finding indicated that both closteroviruses were associated with wilt disease on pineapple plants in Indonesia. Protein analysis by using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that the viruses have a major structural protein with molecular mass of approximately kDa. Flexuous filamentous particles were also observed in electron microscopy preparations from infected plants. These results were in agreement with characteritics of the closteroviruses. Aligments of partial nucleotide sequences of the viral genomes exhibited 96 to 98% homology with that of PMWaV-1 and PMWaV-2 Hawaiian isolates as previously reported by Sether et al. (2001), respectively. Phylogenetic analysis revealed that Indonesian and Hawaiian virus isolates were belong to mealybugtransmitted closterovirus and closely related to Grapevine leafroll-associated virus-3 (GLRaV-3)., Penelitian ini bertujuan untuk mendeteksi dan mengidentifikasi PMWaV yang berasosiasi dengan penyakit layu pada tanaman nanas di Indonesia. Diharapkan penelitian ini dapat memberikan informasi dan laporan pertama mengenai keberadaan PMWaV yang berasosiasi dengan penyakit layu nanas di Indonesia. Hasil deteksi secara serologi dengan metode Tissue blot immunoassays (TBIA) menggunakan dua antibodi monoklonal spesifik terhadap PMWaV-1 maupun PMWaV-2 (Agdia Inc., USA) berhasil mendeteksi keberadaan PMWaV- 1 dan PMWaV-2 pada jaringan daun tanaman nanas yang menunjukkan maupun dari yang tidak menunjukkan gejala layu. Pendeteksian secara molekuler dengan metode reverse transcription-polymerase chain reaction (RT-PCR) menggunakan dua primer yang spesifik terhadap PMWaV-1 dan PMWaV-2 berhasil mengamplifikasi gen Heat Shock Protein 70 (HSP 70) pada kedua virus. Penemuan ini mengindikasikan bahwa PMWaV-1 dan PMWaV-2 berasosiasi dengan penyakit layu nanas yang terjadi di Indonesia. Analisis protein menggunakan sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDSPAGE) menunjukkan adanya sebuah struktural protein besar dengan perkiraan ukuran sebesar 23 kDa. Keberadaan partikel virus berbentuk batang lentur juga teramati pada preparasi mikroskop elektron yang berasal dari tanaman nanas yang terinfeksi virus. Hasil pengamatan menggunakan mikroskop elektron ini sesuai dengan ciri-ciri virus dari anggota Closterovirus. Analisis parsial genom HSP 70 virus layu nanas isolat Indonesia menunjukkan kisaran homologi sebesar 96 hingga 98% dengan PMWaV-1 dan PMWaV-2. Selain itu, analisis filogenetik menunjukkan bahwa isolat PMWaV Indonesia dan Hawaii merupakan anggota Closterovirus yang ditularkan oleh kutu putih, dan memiliki hubungan kekerabatan yang dekat dengan Grapevine leafroll-associated virus-3 (GLRaV-3).
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Judul: Peranan strain pineapple mealybug wilt associated virusdan kutu putih dalam menginduksi gejala layu pada tanaman nanas
Abstrak: ARTA JUNITA HUTAHAYAN. The Role of Pineapple Mealybug Wiltassociated Virus Strain and Mealybug (Dysmicoccus spp.) in Inducing Wilt Symptom on Pineapple Plants. Dibimbing oleh GEDE SUASTIKA dan SOBIR Indonesia is a tropic country which have potential to produce exotic fruits like pineapple. Pineapple is very important fruit for world trade. Indonesia is the third largest pineapple tin exporter after Philippine and Thailand. The main problem in pineapple cultivation is wilt disease. Mealybug wilt of pineapple (MWP) is currently present in pineapple-growing areas of West Java, Indonesia. MWP is characterized by severe tip dieback, downward curling, reddening, and wilting of the leaves which can lead to total collapse of the plant. Mealybug feeding on the pineapple plant has been associated with MWP symptom. Furthermore, flexuous rod-shaped virus particles, designated Pineapple mealybug wilt-associated virus (PMWaV) have been isolated from both symptomatic and asymptomatic pineapple plants. PMWaV is actually a complex of at least two different viruses, PMWaV-1 and PMWaV-2 that are transmitted by mealybug. The objectives of this research are to study the role of PMWaV isolates infection and mealybug feeding in inducing wilt symptom on pineapple plants, and to study the incidence of MWP in pineapple-growing areas of Indonesia. Survey for MWP were conducted in pineapple production areas of East Java (Blitar), West Java (Subang and Bogor), and North Sumatera (Simalungun). The incidence of the disease in all of the areas surveyed were found to be ranging from 50% to 90%. These results indicated that MWP has already spread widely in pineapple-growing areas of Indonesia. Transmission of PMWaV from infected pineapple plant to the pineapple test plants using mealybugs Dysmicoccus spp. under greenhouse condition were successfully conducted. The symptoms on the test plants were the same as that on naturally infected plants. The plants inoculated with virus and colonized by mealybug produce more severe symptoms than the plants inoculated with virus only. This indicated that PMWaV infection and mealybug feeding play important role in inducing wilt symptom. But, some pineapple plants surveyed on the field showing MWP symptoms without colonized by mealybug. This finding suggested that PMWaV likely to be the most important causal agent of the MWP, and mealybug feeding making the symptom more severe.
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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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