<p>ABSTRAK<br />Phytophthora capsici adalah penyebab penyakit busuk pangkal<br />batang yang paling merugikan pada lada di Indonesia dan sulit<br />dikendalikan karena dapat bertahan lama dalam tanah serta memiliki<br />keragaman agresivitas isolat luas. Pengetahuan mengenai keragaman<br />genetik strain-strain P. capsici dapat membantu perancangan strategi<br />efektif pengelolaan patogen. Penelitian ini bertujuan mengevaluasi<br />keragaman dan struktur genetik isolat-isolat P. capsici asal lada<br />menggunakan penanda RAPD. Penelitian dilaksanakan pada bulan<br />Oktober 2009 sampai April 2010 di Laboratorium Biokimia BB Biogen<br />dan Laboratorium Hama dan Penyakit Balittro. Keragaman genetik 59<br />isolat P. capsici yang berasal dari koleksi kultur tahun 1982-2009 dari 37<br />lokasi di Sumatera, Bangka, Jawa, dan Kalimantan, dikarakterisasi<br />menggunakan enam primer RAPD. Pengelompokan menggunakan<br />unweighted pair-group method with arithmatic averaging (UPGMA)<br />berdasarkan profil RAPD membagi ke-59 isolat ke dalam lima gerombol<br />utama; yang menunjukkan adanya keragaman genetik tinggi antar isolat.<br />Pengelompokan RAPD tidak berkaitan dengan asal lokasi isolat. Analysis<br />of molecular variance (AMOVA) juga menunjukkan adanya keragaman<br />genetik yang tinggi di antara isolat-isolat P. capsici, dengan ragam genetik<br />total sebesar 96% terletak di dalam masing-masing pulau (within<br />populations). Namun demikian, terdapat ragam genetik antar isolat dari<br />pulau berbeda (among populations) yang signifikan (4% ; P=0,001), yaitu<br />antar populasi di Sumatera dan Bangka dengan jarak genetik sebesar 0,081<br />(P=0,002). Ketidakterkaitan antara pengelompokan RAPD dengan asal<br />lokasi geografik isolat dan ragam genetik yang tinggi dalam satu pulau<br />dapat diakibatkan oleh terjadinya penyebaran isolat antar daerah, terutama<br />melalui bibit tanaman yang terinfestasi P. capsici. Pencegahan penyebaran<br />isolat antar pulau perlu dilakukan melalui sertifikasi bibit bebas penyakit<br />BPB dan pengembangan sistem perbenihan lokal.<br />Kata kunci: lada, penyakit busuk pangkal batang, Phytophthora capsici,<br />RAPD, keragaman genetik, struktur populasi</p><p>ABSTRACT<br />Phytophthora capsici is the causal agent of foot rot, the most<br />destructive disease of pepper in Indonesia and difficult to control .<br />Knowledge in the genetic structure of P. capsici strains can enrich<br />designing effective disease management strategies. This study was aimed<br />at analyzing the genetic variability and structure of P. capsici isolates from<br />pepper using RAPD. The study was done from October 2009 until April<br />2010 at the Biochemical Laboratory of Indonesian Center for Agriculutral<br />Biotechnology and Genetic Resources Research and Development, and the<br />Plant Pest and Disease Laboratory of the Indonesian Research Institute of<br />Spice and Medicinal Crops. Fifty-nine isolates collected from 1982 to<br />2009 from Sumatera, Bangka, Java, and Kalimantan were characterized<br />based on six RAPD markers. Unweighted pair-group method with<br />arithmatic averaging (UPGMA) clustering based on RAPD profiles<br />divided the isolates into five major cluster, which indicated high genetic<br />variability among isolates. No apparent relationship between RAPD<br />clustering and geographic origin of isolate was observed. Hierarchical<br />partitioning of genetic variation using analysis of molecular variance<br />(AMOVA) confirmed the overall high variability among isolates, with<br />96% of total genetic variance was resided among isolates within islands<br />(within populations). Nevertheless, a small (4%) but significant (P=0.001)<br />genetic variance among isolates between different islands (among<br />populations) were observed, which was detected between populations in<br />Sumatera and Bangka with genetic distance (Ф PT ) as high as 0,081<br />(P=0,002). The lack of association between RAPD clustering and<br />geographic origin as well as high genetic variance within populations may<br />have been the result of movement of isolates between locations, most<br />likely through infested plant cuttings. Use of certified and development of<br />blackpepper clones locally are required to prevent disease spread among<br />islands.<br />Keywords: black pepper, foot rot disease, Phytophthora capsici, genetic<br />diversity, RAPD, population structure</p>
Genetic Diversity and a PCR-Based Method for Xanthomonas axonopodis Detection in Passion Fruit
