Bakteri Endofit dari Tumbuhan Paku-pakuan sebagai Agens Hayati Rhizoctonia solani dan Pemacu Pertumbuhan Tanaman Padi

Rhizoctonia solani is one of the important pathogens that causes sheath blight disease in rice plants that are difficult to be controlled. Biological control with endophytic bacteria is a potential alternative because of its ability to live in plant tissues without causing symptoms of disease and can increase plant growth and resistance. The purpose of this study was to explore endophytic bacteria from root and stem parts from three different types of ferns, namely Salvinia molesta (water nail), Pteris ensiformis (terrestrial nail), and Drymoglossum pilosolloides (epiphytic nails) and to evaluate their potential as biological control agents against R. solani and plant growth promoters. Isolation of endophytic bacteria was grown on trypsic soy agar (TSA) and nutrient agar (NA). Bacterial isolates were purified and tested for their biosafety by hypersensitivity and hemolysis test. A total of 178 isolates of endophytic bacteria were isolated and 88 isolates showed negative reactions after hypersensitivity and hemolysis test. The isolates were tested for their antagonism activity under in vitro test against R. solani and plant growth activity. The result showed four isolates of endophytic bacteria, namely APE15, APE22, APE33, and APE35 with inhibition activity of 27% -76% in three different medium TSA, potato dextrose agar (PDA) and TSA + PDA medium. Endophytic bacteria are also able to increase rice germination up to 4.9%–48.8% and increase rice root display of 68.3% –95.4%, shoot length 53.2%–87.3%, plant fresh weight 49.07%–90.65% and plant dry weight 48.1%–87.3%. These results indicated that ferns contain several endophytic bacteria that can be cultured which have effective antimicrobial compounds, and can be used as biological control agent against R. solani and plant growth promoters.Rhizoctonia solani merupakan salah satu patogen penting penyebab penyakit hawar seludang pada tanaman padi. Patogen ini termasuk yang sulit dikendalikan karena bersifat kosmopolit, mampu bertahan di dalam tanah, dan memiliki kisaran inang yang banyak. Pengendalian secara biologi dengan bakteri endofit merupakan salah satu alternatif yang potensial karena kemampuannya hidup di dalam jaringan tanaman tanpa menimbulkan gejala penyakit dan dapat meningkatkan pertumbuhan serta ketahanan tanaman. Tujuan penelitian ini ialah mengeksplorasi bakteri endofit dari bagian batang akar dari tiga jenis tumbuhan paku yang berbeda, yaitu Salvinia molesta (paku air), Pteris ensiformis (paku terestrial), dan Drymoglossum pilosolloides (paku epifit) dan mengevaluasi potensinya sebagai agens hayati R. solani dan pemacu pertumbuhan tanaman. Isolasi bakteri dilakukan pada medium tripsic soy agar (TSA) dan nutrient agar (NA). Isolat bakteri dimurnikan dan diuji keamanan hayati dengan uji hipersensitifitas dan hemolisis. Hasil penelitian diperoleh 178 isolat bakteri endofit dan sebanyak 88 isolat menunjukkan reaksi negatif pada uji hipersensitisfitas dan uji hemolisis. Selanjutnya, isolat tersebut diuji dual test secara in vitro terhadap R. solani dan didapatkan 4 isolat bakteri endofit (APE15, APE22, APE33, dan APE35) dengan daya hambat dari 27–76% pada medium TSA, agar-agar dekstrosa kentang (ADK), dan TSA + ADK. Hasil uji pertumbuhan empat isolat terhadap benih padi varietas Situ Bagendit menunjukkan bahwa bakteri endofit mampu meningkatkan persentase perkecambahan padi 4.9% – 48.8%, meningkat panjang akar padi 68.3%–95.4%, panjang pucuk 53.2%–87.3%, bobot segar 49.07%–90.65%, dan bobot kering 48.1%–87.3%. Hasil ini menunjukkan bahwa tumbuhan paku mengandung beberapa bakteri endofit yang dapat dikulturkan dan memiliki senyawa antimikrob yang efektif, serta dapat digunakan sebagai sumber agens hayati terhadap patogen R. solani dan pemacu pertumbuhan tanaman