Judul: Genetic Engineering of Potato (Solanum tuberosum L.) cv IPB CP1 with LYZ-C Gene to Control Bacterial Wilt Disease
Abstrak: Kentang (Solanum tuberosum L.) merupakan salah satu tanaman pangan pokok penting selain padi, gandum dan jagung serta menempati urutan ketiga berdasarkan tingkat konsumsi secara global. Kentang kultivar IPB CP1 merupakan kultivar yang dikembangkan dari mutasi kentang kultivar Atlantik dan memiliki karakteristik umbi yang sesuai sebagai olahan keripik kentang (potato chips). Infeksi penyakit layu bakteri yang disebabkan oleh bakteri Ralstonia solanacearum menjadi salah satu kendala dalam budidaya tanaman kentang di Indonesia. Infeksi bakteri patogen tersebut pada tanaman dapat berdampak serius terhadap kehilangan hasil panen. Perakitan tanaman kentang yang resisten terhadap penyakit bakteri dapat dilakukan melalui rekayasa genetik. Lisozim merupakan enzim-enzim glikosida yang dapat mengkatalisis pemutusan ikatan antara molekul N-asetil-D-glukosamin (NAG) dan asam N-asetil-D-muramat (NAM) sebagai penyusun peptidoglikan pada dinding sel bakteri. Ekspresi gen LYZ-C penyandi lisozim pada tanaman dapat meningkatkan resistensi tanaman terhadap infeksi bakteri patogen. Agrobacterium tumefaciens strain LBA4404 yang mengandung plasmid pCXSN-Lys(+) digunakan untuk mengintroduksikan gen LYZ-C ke dalam genom tanaman kentang kultivar IPB CP1. Tranformasi genetik pada kentang kultivar IPB CP1 terhadap 200 eksplan ruas batang telah berhasil dilakukan. Pembentukan kalus dan regenerasi kalus menjadi tunas berhasil diinduksi pada media MS yang mengandung IAA 1 mg/l, trans-zeatin 3 mg/l dan GA3 0,5 mg/l. Pada penelitian ini efisiensi transformasi dan efisiensi regenerasi yang diperoleh sebesar 35,1% dan 54,7%. Hasil analisis PCR menggunakan primer Lys114-F dan Nost2-R terhadap 10 tanaman transgenik putatif menunjukkan 6 tanaman mengandung transgen LYZ-C yang ditandai dengan adanya amplikon berukuran 565 pb. Uji resistensi secara in vitro pada 4 klon tanaman transgenik dan 1 tanaman non-transgenik, menunjukkan bahwa klon tanaman transgenik memiliki resistensi yang lebih baik terhadap infeksi R. solanacearum penyebab layu bakteri dibandingkan dengan tanaman CP1 non-transgenik. Hal ini menunjukkan bahwa gen LYZ-C yang diintroduksikan ke dalam tanaman kentang kultivar IPB CP1 meningkatkan resistensi tanaman terhadap penyakit layu bakteri. Pada penelitian ini klon CP1L3 merupakan tanaman transgenik yang paling resisten terhadap R. solanacearum dan memiliki nilai indeks penyakit terendah., Potato (Solanum tuberosum L.) is the most important crops besides rice, wheat, corns and includes in the third world crop plants in terms of global consumption. IPB CP1 cultivar is a derivative of radiated Atlantic cultivar and produce suitable tuber characteristics for potato chips. In Indonesia, bacterial wilt infection caused by Ralstonia solanacearum is one of the problems in potato cultivation. Infection of this patohegen has a serious effect to the yield losses. Assembly of transgenic potato resistant to bacterial wilt could be realize through genetic engineering. Lysozyme belongs to the glycoside enzymes that catalyze the cleavage of peptidoglican components of bacterial cell wall. LYZ-C gene expression can enhance the plant resistance against pathogenic bacteria. Agrobacterium tumefaciens strain LBA4404 harboring the pCXSN-Lys(+) used to introduces LYZ-C gene into the plant genome. Genetic transformation of IPB CP1 cultivar by using 200 internodes as the explants was done successfully. Callus formation and regeneration were induced successfully on MS medium containing IAA 1 mg/l, trans-zeatin 3 mg/l dan GA3 0,5 mg/l. In this study, the transformation efficiency and regeneration efficiency were 35,1% and 54,7%, respectively. Based on PCR analysis to 10 putative transgenic plants with Lys114-F and Nost2-R primers, confirmed that
Keyword: Agrobacterium tumefaciens, gen LYZ-C, kentang kultivar IPB CP1, penyakit layu bakteri, transformasi genetik

Judul: Resistance Analysis of Transgenic Potato cv. IPB CP3  Containing LYZ-C Against Soft Rot Disease
Abstrak: Kentang kultivar IPB CP3 transgenik yang membawa gen LYZ-C telah dirakit dan lebih resisten terhadap penyakit layu bakteri yang disebabkan bakteri Ralstonia solanacearum. Selain penyakit layu bakteri, produksi kentang paling banyak dihambat oleh penyakit busuk lunak. Penelitian ini bertujuan menganalisis resistensi tanaman kentang kultivar IPB CP3 transgenik terhadap penyakit busuk lunak secara in vitro. Isolat bakteri diisolasi dari wortel yang menunjukkan gejala penyakit busuk lunak. Analisis resistensi bakteri dilakukan pada 3 klon tanaman transgenik yang memiliki pertumbuhan paling baik di media seleksi yang mengandung 30 mg/L higromisin. Tanaman ditumbuhkan di dalam botol yang mengandung 40 mL vermikulit dan 30 mL media MS, kemudian diinokulasi bakteri. Klon CP3lyz2 memiliki tingkat sensitivitas paling rendah terhadap bakteri saat 28 HSI. Bakteri diisolasi dari tanaman uji dan diidentifikasi secara molekuler dengan sekuensing gen 16s rRNA. Hasil identifikasi bakteri adalah Pseudomonas palleroniana, yang merupakan bakteri penyebab busuk lunak pada kentang yang baru pertama kali dilaporkan di Indonesia., The transgenic potato cv. IPB CP3 containing the LYZ-C gene was constructed and proven to be more resistant to bacterial wilt disease caused by Ralstonia solanacearum. Apart from bacterial wilt disease, potato production is mostly inhibited by soft rot disease. This study aims to analyze the resistance of transgenic potato cv. IPB CP3 to soft rot disease in vitro. Bacteria used in the research were isolated from carrot plants showing symptoms of soft rot disease. Analysis of resistance to bacteria was carried out on 3 clones of transgenic plants that showed the best growth in selection media with 30 mg/L hygromycin. Plants were grown in bottles containing 40 mL of vermiculite and 30 mL of MS medium, and then inoculated with bacteria. Clone CP3lyz2 had the least sensitivity level against bacteria at 28 DAI. Bacteria were then isolated from tested plants and identified molecularly using 16s rRNA gene sequence. The identification result showed that the bacterium was Pseudomonas palleroniana, which is the first reported causative agent of soft rot disease related to potato in Indonesia.
Keyword: busuk lunak, in vitro, kentang kultivar IPB CP3, LYZ-C, tanaman transgenik

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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