Uji Potensi Bakteri Antagonis Sebagai Agen Pengendali Hayati Penyakit Layu Fusarium dan Pemacu Pertumbuhan Tanaman Krisan (Chrysanthemum sp.)

Abstract

The aims of this study were to find and identify antagonistic bacteria against fungal phytopathogen (Fusarium oxysporum) causingFusarium wilt of chrysanth in vitro and plastic bag pot application, followed with characterization of plant growth promoting properties from bacterial isolates includingIndole Acetic Acid(IAA) production and phosphate solubilizing. Eight bacterial strains, collection of Laboratory of Microbiology, Universitas Sumatera Utara, were tested against Fusarium oxysporum in dual culture assay. Two bacterial strains, were closed to Bacillus amyloliquefaciens and Pseudomonas versuta, showed promising antagonism along with production of IAA and phosphate solubilizing properties in vitro. Plastic bag pot application resulted in considerably decrease of disease intensity caused by F. oxysporum, after being applied with two antagonistic bacteria. The results may promote the use of bacterial strains in large field application to chrysanth farm in the future.

Tujuan penelitian ini adalah mendapatkan dan mengidentifikasi isolat bakteri antagonis yang menekan pertumbuhan Fusarium oxysporum penyebab penyakit layu Fusarium pada krisan (Chrysanthemum sp.) secara in vitro dan in vivo, mengetahui kemampuan bakteri antagonis dalam menghasilkan asam indol asetat (IAA), mengetahui kemampuan bakteri antagonis dalam melarutkan fosfat. Sebanyak 8 isolat bakteri antagonis koleksi laboratorium Mikrobiologi Universitas Sumatera Utara diuji kemampuan antifungalnya. Dua isolat bakteri yang diidentifikasi mendekati Bacillus amyloliquefaciens dan Pseudomonas versuta memiliki kemampuan paling potensial menghambat pertumbuhan Fusarium oxysporum, mampu memproduksi IAA, dan mampu melarutkan fosfat secara in vitro. Uji in vivo menunjukkan bahwa kedua isolat bakteri tersebut mampu menurunkan intensitas serangan penyakit layu Fusarium serta meningkatkan pertumbuhan tanaman krisan.