PENGARUH PERUBAHAN BAKTERIOMA-Beauveria bassiana PADA PATOGENISITASNYA TERHADAP Spodoptera exigua

Muhammad Ridho Illahi, Ir. Jaka Widada, M.P., Ph.D.; Dr. Ir. Ngadiman, M.Si.

2024 | Skripsi | MIKROBIOLOGI PERTANIAN

Pemanfaatan jamur entomopatogen Beauveria bassiana merupakan salah satu pengendalian Spodoptera exigua yang ramah lingkungan. Selain faktor lingkungan, viabilitas konidia, dan jenis hama, patogenitas jamur juga dipengaruhi oleh interaksi jamur dan bakteri. Penelitian ini bertujuan mengetahui pengaruh perubahan komposisi bakterioma terhadap morfologi dan patogenisitas Beauveria bassiana dalam menginfeksi ulat bawang. Perubahan komposisi dilakukan dengan penambahan antibakteri berupa kanamycin dan chloramphenicol sebanyak 20 µg/ml pada media PDA. Perubahan bakterioma diamati melalui identifikasi morfologi secara makroskopis dan mikroskopis serta analisis molekuler dengan metode  Ribosomal Intergenic Spacer Analysis (RISA). Selanjutnya, dilakukan uji patogenisitas Beauveria bassiana terhadap mortalitas Spodoptera exigua dengan metode dipping pada suspensi konidia dengan konsentrasi 10⁷ konidia/mL.  Hasil penelitian menjukkan bahwa pemberian antibakteri pada Beauveria bassiana mengakibatkan perlambatan pertumbuhan serta perubahan warna koloni, dan tekstur. Perubahan bakterioma akibat penambahan antibakteri ditunjukkan dengan adanya perubahan jumlah pita (band) dan ukuran fragmen DNA. Perubahan tersebut meningkatkan patogenitas Beauveria bassiana terhadap ulat bawang merah secara signifikan dalam kurun waktu 3 hari setelah penetrasi.

The utilization of the entomopathogenic fungus Beauveria bassiana is a promising eco-friendly approach to control Spodoptera exigua or beet armyworms. Besides environmental factors, conidial viability, and host species, the pathogenicity of this fungus is also influenced by its interaction with bacteria. This study aimed to investigate the impact of altering the bacterial community on the morphology and pathogenicity of B. bassiana in infecting beet armyworms. The bacterial community was modified by adding 20 µg/mL of kanamycin and chloramphenicol to potato dextrose agar (PDA) media. Changes in the bacterial community were observed through macroscopic and microscopic morphological identification, as well as molecular analysis using ribosomal intergenic spacer analysis (RISA). Furthermore, the pathogenicity of B. bassiana against Spodoptera exigua mortality was analyzed using the dipping method in a conidial suspension at a concentration of 10⁷ conidia/mL. Results showed that the addition of antibiotics to B. bassiana cultures resulted in growth retardation and alterations in colony color and texture. Changes in the bacterial community due to the addition of antibiotics were indicated by alterations in the number and size of DNA fragments. These changes significantly increased the pathogenicity of B. bassiana against beet armyworms within 3 days post-penetration

Kata Kunci : bacteriome, Beauveria bassiana, Spodoptera exigua, biocontrol.