Isolasi Dan Identifikasi Bakteri Endofit Asal Tanaman Ficus Sp. Di Sekitar Sumber Air Panas Tinggi Raja Kabupaten Simalungun Sebagai Agen Biofertilizer Pelarut Fosfat

Abstract

Bakteri endofit merupakan mikroorganisme yang hidup di dalam jaringan tanaman tanpa menimbulkan gejala penyakit dan berpotensi dimanfaatkan sebagai biofertilizer ramah lingkungan. Penelitian ini bertujuan untuk mengisolasi, mengidentifikasi, dan mengevaluasi kemampuan bakteri endofit asal daun Ficus sp. sebagai kandidat biofertilizer pelarut fosfat. Isolasi dilakukan melalui sterilisasi permukaan daun dan penanaman pada media Nutrient Agar (NA), dilanjutkan dengan karakterisasi morfologi koloni dan pewarnaan Gram. Uji patogenisitas dilakukan menggunakan metode reaksi hipersensitif pada daun Mirabilis jalapa, sedangkan uji pelarutan fosfat dilakukan pada media Pikovskaya dengan perhitungan Indeks Pelarutan Fosfat (IPF). Dari 16 potongan daun diperoleh 11 isolat bakteri endofit dengan karakteristik morfologi yang beragam. Uji hipersensitif menunjukkan 5 isolat bersifat nonpatogen dan 6 isolat patogen. Dari 5 isolat nonpatogen tersebut, tiga isolat mampu membentuk zona bening yang menunjukkan kemampuan melarutkan fosfat. Isolat BEDP 1 menunjukkan nilai Indeks Pelarutan Fosfat tertinggi sebesar 3,42 yang tergolong tinggi. Hasil penelitian menunjukkan bahwa bakteri endofit asal daun Ficus sp., berpotensi dikembangkan sebagai agen pelarut fosfat dalam mendukung pertanian berkelanjutan. Endophytic bacteria are microorganisms that live within plant tissues without causing disease symptoms and have potential to be utilized as environmentally friendly biofertilizers. This study aimed to isolate, identify, and evaluate the phosphate-solubilizing ability of endophytic bacteria isolated from the leaves of Ficus sp. as potential biofertilizer candidates. Isolation was carried out through surface sterilization of leaves followed by cultivation on Nutrient Agar (NA). The isolates were characterized based on colony morphology and Gram staining. Pathogenicity testing was conducted using the hypersensitive reaction method on Mirabilis jalapa leaves, while phosphate-solubilizing activity was evaluated on Pikovskaya medium by calculating the Phosphate Solubilization Index (PSI). From 16 leaf segments, 11 endophytic bacterial isolates were obtained with diverse morphological characteristics. The hypersensitive test showed that five isolates were non-pathogenic and six were pathogenic. Of the five non-pathogenic isolates, three were able to produce clear zones indicating phosphate-solubilizing activity. Isolate BEDP 1 exhibited the highest Phosphate Solubilization Index value of 3.42, categorized as high. The results indicate that endophytic bacteria isolated from Ficus sp., have potential to be developed as phosphate-solubilizing agents to support sustainable agriculture.