Penapisan aktinobakteria rhizosfer padi sebagai agens pengendali hayati Xanthomonas oryzae pv. oryzae pathogen penyebab penyakit hawar daun bakteri

Abstract

Bacterial leaf blight caused by X.o. pv. oryzae is an important disease of rice plants. Actinobacteria has potential as biological agents to control X.o. pv. oryzae because it has the ability to produce bioactive compounds. This study aimed to select actinobacteria isolates that can suppress the development of X.o. pv. oryzae and has the potential to stimulate the growth of rice plants in-planta, as well as to determine the ability of actinobacteria in producing enzymes that inhibit the development of X. oryzae pv. oryzae. The research consisted of four stages, namely: isolation, selection, characterization, and potential inhibition of actinobacterial isolates. A total of 30 isolates were successfully isolated from the rhizosphere of rice plants in three districts of West Sumatra, and as many as 25 isolates were successfully selected based on biosafety tests. The results of the in-planta test showed that 10 isolates had the ability to increase the growth and suppresed the development of bacterial leaf blight. The results of the antagonist test showed that 5 isolates inhibited of X.o. pv. oryzae by 11.66-29.66%. Five isolates were selected, namely: APRD 3I211, APRD 1I122APRP 2S121, APRP 1I121, APRP 3I212 wich capable of produce protease enzymes, cellulases, amylase, and secondary metabolites.ABSTRAK Penyakit hawar daun bakteri yang disebabkan oleh Xanthomonas oryzae. pv. oryzae merupakan penyakit penting tanaman padi. Aktinobakteria memiliki potensi sebagai agens hayati untuk mengendalikan X. oryzae. pv. oryzae karena memiliki kemampuan dalam menghasilkan senyawa bioaktif. Penelitian ini bertujuan untuk menyeleksi isolat aktinobakteria yang dapat menekan perkembangan X. oryzae. pv. oryzae dan memiliki potensi dalam memacu pertumbuhan tanaman padi secara in-planta, serta mengetahui kemampuan aktinobakteria dalam menghasilkan enzim penghambat perkembangan X. oryzae. pv. oryzae. Penelitian terdiri dari empat tahap, yaitu: isolasi, seleksi, karakterisasi, dan potensi daya hambat isolat aktinobakteria. Sebanyak 30 isolat berhasil diisolasi dari rizosfer tanaman padi di tiga Kabupaten Sumatera Barat, dan sebanyak 25 isolat berhasil diseleksi berdasarkan uji keamanan hayati. Hasil uji in-planta menunjukkan 10 isolat memiliki kemampuan dalam meningkatkan pertumbuhan dan menekan perkembangan hawar daun bakteri. Hasil uji antagonis menunjukkan 5 isolat menghasilkan penghambatan terhadap X. oryzae. pv. oryzae sebesar 11,66-29,66%. Lima isolat terpilih yaitu: APRD 3I211, APRD 1I122, APRP 2S121, APRP 1I121, APRP 3I212 terbukti mampu menghasilkan enzim protease, selulase, amilase, metabolit sekunder.