Penanda ISSR ISSR 1, 4, 6 dan 8
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5 EVALUASI KETAHANAN JERUK KEPROK SOE
TERHADAP PENYAKIT HUANGLONGBING
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Evaluation of SoE Mandarine to Huanglongbing Diseases Resistance Abstrak
Sifat ketahanan tanaman terhadap penyakit sangat diperlukan untuk menghindari dan mempertahankan tanaman dari serangan patogen. Individu-
individu mutan harapan yang telah diperoleh pada penelitian tahap sebelumnya dilakukan
pengujian untuk
melihat ketahanannya
terhadap penyakit
Huanglongbing. Tujuan penelitian tahap ini adalah 1 Mengevaluasi ketahanan individu-individu mutan harapan jeruk keprok SoE terhadap penyakit
Huanglongbing; 2 Memperoleh individu-individu mutan harapan tahan terhadap penyakit Huanglongbing. Individu-individu mutan harapan, hasil embriogenesis
somatik dan telah melewati proses mutasi, yang telah diketahui memiliki perbedaan secara genotipe, kemudian dilakukan pengujian ketahanan terhadap
penyakit Huanglongbing. Serangga vektor Diaphorini citri diberikan periode akuisisi penyebab penyakit selama seminggu pada tanaman jeruk yang telah
dideteksi secara molekuler positif mengandung penyakit ini. Prosedur selanjutnya infestasi vektor penyakit untuk menguji ketahanan individu-individu mutan
harapan dalam kurun waktu tiga bulan. Pengujian terhadap adanya serangan penyakit Huanglongbing pada individu-individu mutan harapan jeruk ini diamati
berdasarkan 1 Gejala eksternal; 2 Gejala internal akumulasi pati; 3 Gejala internal analisis mikroskopis histopatologi; 4 Deteksi dengan teknik PCR
menggunakan penanda spesifik OI1 dan OI2c; dan 5 Perkembangan jumlah serangga vektor Diaphorini citri. Individu-individu mutan harapan yang diuji
tidak menampakkan gejala penyakit HLB pada daun. Deteksi dengan penanda spesifik OI1 dan OI2c hasilnya adalah negatif. Pita DNA dengan ukuran 1160 bp
hasil amplifikasi dengan penanda spesifik tersebut tidak terbaca. Hasil uji pati- yodium tidak memperlihatkan perubahan warna hitam total pada bagian berkas
pembuluh angkut floem. Analisis histopatologi individu sampel uji mutan harapan tidak memperlihatkan pelebaran ukuran jaringan floem yang mendorong jaringan
xilem ke arah sisi atas daun upper side. Perkembangan jumlah serangga vektor D. citri pembawa penyebab penyakit Huanglongbing tidak mengalami
pertambahan jumlah selama proses uji ketahanan penyakit.
Kata kunci : Diaphorina citri, floem, Candidatus Liberibacter asiaticus, tulang
daun
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Sebagian isi dari Bab ini sementara dalam proses review di Jurnal Internasional terindeks Scopus “Journal Agricultural Science and Technology
59
Abstract
Plant resistance to disease is a character that necessary to avoid and defend the plant against disease. Individual samples of mutants putative that have been
obtained in the previous stage of the research were evaluated for their resistance to Huanglongbing disease. The research objectives of this phase are 1 To evaluate
the resistance of individual of SoE mandarine putative mutant against Huanglongbing disease; 2 To obtain candidate of individual mutant putative
which are resistant to Huanglongbing disease. Individuals samples, generated from somatic embryogenesis which has undergone mutation process, to produce
genotypic differences, were then tested for Huanglongbing disease resistance. Insect vectors Diaphorini citri, were fed to acquire the pathogen on positively
infected citrus plant for one week. The insect vectors were infested on healthy putative plant mutant samples to allow inoculation feeding and also to observe the
insect survival during three months. Detection of the presence pathogen and disease establishment in inoculated plants were based on: 1 external symptoms;
2 Symptoms of internal accumulation of starch; 3 Internally symptoms of microscopic histopathological analysis; 4 Detection by PCR using specific
markers OI1 and OI2c; and 5 The number of insect vectors Diaphorini citri remained alive. Individuals putative mutant samples previously inoculated with
the pathogen did not show typical leave symptoms of HLB disease. Starch-iodine test of leaf midribs showed no entire black discoloration of the phloem vessels as
an indicator of starch accumulation. Histopathology analysis of individual test samples putative mutants did not show widening tissue size of phloem which
xylem tissue extending toward the upper side. The result of detection with a specific marker OI2cOI1 was negative. DNA bands with a size of 1160 bp
amplification product with the specific marker were negative. The number of insect vectors on infested plants did not increase during observation that indicated
low survivality of the insects.
Keywords : Candidatus Liberibacter asiaticus, Diaphorini citri, petiole, phloem
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