PATOGENISITAS ISOLAT Botryodiplodia spp. TERHADAP BIBIT JABON (Anthocephalus cadamba (Roxb.) Miq) - Ai Rosah Aisah; Bonny PW Soekarno; Achmad Achmad (Jurnal Penelitian Hutan Tanaman, 2017)
ABSTRACTBotryodiplodia spp. potentially cause dieback disease on jabon (Anthocephalus cadamba (Roxb.) Miq) seedlings. Five isolates of Botryodiplodia spp were inoculated on jabon seedling to find out its virulence levels, mechanism of pathogen attack and mechanism of host plant defense. The virulence levels was estimated by disease severity of host plants; the pathogen attack mechanism was done by measuring pectinase and cellulase enzyme activities; whereas host plant defense mechanism was determined by measuring peroxidase enzyme activity. The virulent isolates caused disease severity > 50%. Botryodiplodia sp1, Botryodiplodia sp2, and Botryodiplodia sp3 showed pectinase activities of 21.31; 18.13; 26.08 U/ml, and cellulase 0.014; 0.015; 0.023 U/ml, respectively. The peroxidase activity of host plants after pathogen inoculated was ranging from 0.0006 to 0.0012 UAE/g. Based on this research, three Botryodiplodia spp. isolates were virulent on jabon seedlings and involved enzymatic strength as attack mechanism, whereas the host plant defense mechanism involved peroxidase activity.Key words: Dieback, host defense, pathogen attack ABSTRAKIIsolat Botryodiplodia spp. berpotensi menyebabkan penyakit mati pucuk pada bibit jabon (Anthocephalus cadamba (Roxb.) Miq). Lima isolat Botryodiplodia spp. diinokulasikan terhadap bibit jabon untuk menentukan tingkat virulensi isolat, mengetahui mekanisme infeksi patogen dan mekanisme pertahanan tanaman inang. Tingkat virulensi isolat ditentukan melalui nilai keparahan penyakit pada tanaman inang; mekanisme infeksi patogen dilakukan melalui pengukuran aktivitas enzim pektinase dan selulase; sedangkan mekanisme pertahanan tanaman inang dilakukan melalui pengukuran aktivitas enzim peroksidase. Isolat Botryodiplodia spp. yang virulen menghasilkan keparahan penyakit > 50%. Isolat-isolat tersebut adalah Botryodiplodia sp. 1, Botryodiplodia sp. 2, dan Botryodiplodia sp. 3 yang secara berturut-turut menunjukkan aktivitas pektinase sebesar 21,31; 18,13; 26,08 U/ml, dan aktivitas selulase sebesar 0,014; 0,015; 0,023 U/ml. Adapun aktivitas peroksidase tanaman inang setelah diinokulasi patogen, yaitu berkisar 0,0006-0,0012 UAE/g. Berdasarkan penelitian ini, tiga isolat Botryodiplodia spp. bersifat virulen terhadap bibit jabon dan melibatkan kekuatan enzim sebagai mekanisme infeksi, sedangkan mekanisme pertahanan inang melibatkan aktivitas peroksidase.Kata kunci: Infeksi patogen, mati pucuk, pertahanan inang