Agustina, Nensi and Dr. Suharjono, M.Si and Dr. Anang Triwiratno, MP (2024) Isolasi Dan Uji Potensi Kapang Rhizosfer Indigenous Tanaman Jeruk Siam (Citrus Nobilis) Pengendali Lasiodiplodia Theobromae Dari Kalimantan Timur. Magister thesis, Universitas Brawijaya.
Abstract
Jeruk Siam (Citrus nobilis) mengandung minyak esensial dan antioksidan yang lebih tinggi dibandingkan dengan jenis jeruk lainnya, serta banyak dibudidayakan di Indonesia. Salah satu sentra budidaya jeruk siam di Indonesia yaitu Kalimantan Timur. Permasalahan utama dalam budidaya jeruk siam adalah Penyakit Diplodia yang disebabkan kapang Lasiodiplodia theobromae. Secara umum, pengendalian penyakit tersebut menggunakan fungisida sintetis. Penggunaan fungisida tersebut secara berkelanjutan dapat merusak ekosistem. Kapang rhizosfer merupakan salah satu agen pengandali hayati yang efektif dan tidak berbahaya bagi ekosistem. Penelitian ini bertujuan untuk menganalisis struktur komunitas kapang rhizosfer dan karakteristik tanah, menguji potensi dan mengidentifikasi spesies kapang rhizosfer yang paling tinggi potensinya dalam menghambat pertumbuhan Lasiodiplodia theobromae. Sampel tanah rhizosfer diambil dari lahan kering dan rawa perkebunan Jeruk Siam di Desa Padang Pengrapat, Kecamatan Tanah Grogot, Kabupaten Paser, Kalimantan Timur. Tanah rhizosfer dianalisis karakter fisika (suhu dan kelembaban), kimia (pH, bahan organik, C-Organik, dan N-total), dan biologi (kelimpahan kapang). Kapang rhizosfer diisolasi dari tanah sekitar perakaran tanaman jeruk yang sehat dengan metode serial dillution, sedangkan kapang patogen diisolasi dari batang jeruk yang terinfeksi diplodia dengan metode direct planting. Isolat kapang rhizosfer dianalisis struktur komunitasnya berdasarkan Indeks Nilai Penting (INP). Karakter tanah dan kelimpahan kapang dianalisis korelasi menggunakan Principal Component Analysis dan Structural Equation Modelling. Setiap isolat kapang dimurnikan menggunakan metode mono spore. Setiap isolat kapang rhizosfer diskrining berdasarkan potensi penghambatannya terhadap pertumbuhan Lasiodiplodia theobromae dengan metode dual culture potongan koloni. Isolat kapang rhizosfer dengan potensi penghambatan lebih dari 60% diuji antagonisme dengan kapang patogen berdasarkan uji kultur ganda mono spora. Data daya hambat dianalisis ragam one-way Annova dilanjutkan uji Beda Nyata Jujur (BNJ) ρ value < 0,05. Isolat kapang rhizosfer yang memiliki potensi penghambatan tertinggi diuji pertumbuhannya pada media dengan pH 3, 4, 5, dan 5,6; kemudian dikarakterisasi fenotipnya dan diidentifikasi berdasarkan similaritas sekuen 18S rDNA. Kapang patogen diidentifikasi berdasarkan similaritas sekuen Internal Transcribed Spacer (ITS) rDNA. Pohon filogeni yang menunjukkan kekerabatan isolat uji dengan strainstrain acuan dikonstruksi menurut algoritma Neighbor Joining dengan model Tamura-Nei.viii Tanah perkebunan jeruk di lahan rawa memiliki kandungan organik tanah (bahan organik, C-Organik, N-total), kelimpahan, dan kelembaban lebih tinggi dibandingkan tanah di lahan kering. Hasil isolasi kapang rhizosfer didapatkan 28 isolat dengan karakter yang berbeda dari kedua jenis lahan. Isolat kapang TR23 dan TR22 memiliki INP tertinggi baik di lahan rawa maupun lahan kering berturut-turut sebesar 23% dan 26%. Kelimpahan kapang rhizosfer berkorelasi positif dengan kelembaban tanah, bahan organik, C-Organik, dan Ntotal; sebaliknya kelimpahan kapang berkorelasi negatif dengan suhu dan pH tanah. Kapang rhizosfer antagonis sebanyak 21 isolat memiliki potensi penghambatan lebih dari 60% terhadap kapang patogen D13.C2. Isolat TR3, TR5, TR32, TR33, TR37, dan TR40 memiliki daya hambat tertinggi hingga 89,31% serta mampu tumbuh pada media dengan pH masam. Isolat kapang rhizosfer TR3, TR5, TR32, TR33, TR37, dan TR40 diidentifikasi secara berturutan sebagai Trichoderma koningiopsis T-404, Trichoderma koningii dl-49, Mucor indicus FJ-M-5, Trichoderma aggressivum CBS100525, Trichoderma reeseiT, dan Mucor irregularis CBS 103.93T dengan similaritas secara berurutan 98,83%; 99,16%, 99,1%, 98,81%; 100%; dan 99,6%. Isolat kapang D13.C2 patogen jeruk siam diidentifikasi sebagai Lasiodiplodia theobromae JB dengan similaritas 99,93%. Keenam isolat kapang rhizosfer potensial tersebut dapat dikembangkan sebagai agen pengendali hayati Lasiodiplodia theobromae kapang patogen penyebab penyakit Diplodia pada tanaman Jeruk Siam.
English Abstract
Tangerine (Citrus nobilis) contain higher levels of essential oils and antioxidants than other types of oranges, and are widely cultivated in Indonesia. One of the Tangerine cultivation centers in Indonesia is East Kalimantan. The main problem in cultivating Tangerine is Diplodia disease caused by the mould Lasiodiplodia theobromae. In general, controlling this disease uses synthetic fungicides. Continuous use of these fungicides can damage the ecosystem. Rhizosphere mould is an effective and harmless biological control agent for the ecosystem. This research aims to analyze the structure of the rhizosphere mould community and soil characteristics, test the potential and identify the rhizosphere mould species with the highest potential in inhibiting the growth of Lasiodiplodia theobromae. Rhizosphere soil samples were taken from dry land and swamps of Tangerine plantations in Padang Pengrapat Village, Tanah Grogot District, Paser Regency, East Kalimantan. Rhizosphere soil was analyzed for physical (temperature and humidity), chemical (pH, organic matter, C-Organic, and N-total) and biological (mould abundance) characteristics. Rhizosphere fungi were isolated from the soil around the roots of healthy citrus plants using the serial dilution method, while pathogenic fungi were isolated from diplodia-infected citrus stems using the direct planting method. Rhizosphere mould isolates were analyzed for their community structure based on the Importance Value Index (IVI). Soil characteristics and mould abundance were analyzed for correlation using Principal Component Analysis and Structural Equation Modelling. Each mould isolate was purified using the mono spore method. Each rhizosphere mould isolate was screened based on its potential to inhibit the growth of Lasiodiplodia theobromae using the dual colony cutting culture method. Rhizosphere mould isolates with an inhibitory potential of more than 60% were tested for antagonism with pathogenic moulds based on the mono-spore double culture test. Inhibitory power data were analyzed by one-way ANOVA followed by the Honestly Significant Difference (HSD) test ρ value < 0.05. The rhizosphere mould isolates that had the highest inhibitory potential were tested for growth on media with pH 3, 4, 5, and 5.6; Then the phenotype was characterized and identified based on the similarity of the 18S rDNA sequence. Pathogenic moulds are identified based on the similarity of the Internal Transcribed Spacer (ITS) rDNA sequence. A phylogenetic tree showing the relationship between the test isolates and the reference strains was constructed using the Neighbor Joining algorithm with the Tamura-Nei model. Tangerine plantation soil in swamp land has higher soil organic content (organic matter, C-Organic, N-total), abundance and moisture than soil in dry land. The results of rhizosphere mould isolation showed that there were 28 isolates with different characteristics from the two types of land. Mould isolates TR23 and TR22 had the highest INP in both swamp and dry land, respectively, at 23% and 26%. Rhizosphere mould abundance was positively correlated with soil moisture, organic matter, C-Organic, and N-total; conversely, mould abundance was negatively correlated with temperature and soil pH. 21 isolates of antagonistic rhizosphere mould had an inhibitory potential of more than 60% against thex pathogenic mould D13.C2. Isolates TR3, TR5, TR32, TR33, TR37, and TR40 have the highest inhibitory power of up to 89.31% and are able to grow on media with acid pH. Rhizosphere mould isolates TR3, TR5, TR32, TR33, TR37, and TR40 were identified respectively as Trichoderma koningiopsis T-404, Trichoderma koningii dl-49, Mucor indicus FJ-M-5, Trichoderma aggressivum CBS100525, Trichoderma reeseiT, and Mucor irregularis CBS 103.93T with sequential similarity of 98.83%; 99.16%, 99.1%, 98.81%; 100%; and 99.6%. The mould isolate D13.C2, the Siamese orange pathogen, was identified as Lasiodiplodia theobromae JB with a similarity of 99.93%. These six potential rhizosphere mould isolates can be developed as biological control agents for Lasiodiplodia theobromae, the pathogenic mould that causes Diplodia disease in Tangerine plants.
| Item Type: | Thesis (Magister) |
|---|---|
| Identification Number: | 0424090042 |
| Divisions: | S2/S3 > Magister Biologi, Fakultas MIPA |
| Depositing User: | Unnamed user with username nova |
| Date Deposited: | 06 Sep 2024 06:30 |
| Last Modified: | 06 Sep 2024 06:30 |
| URI: | http://repository.ub.ac.id/id/eprint/230265 |
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