Growth Inhibition of Rhizoctonia solani and Its Infection Inhibition on the Rice Seedling by Rice Endophytic Bacteria

Growth Inhibition of Rhizoctonia solani and Its Infection Inhibition on the Rice Seedling by Rice Endophytic Bacteria Rhizoctonia solani is one of the important pathogens in rice plants that can cause blight on seeds, leaves, and leaf sheaths. This rice sheath blight is a serious problem in many rice growing countries, including Indonesia. Controls that rely on the use of synthetic pesticides and resistant varieties often cause new problems, both environmental pollution and the emergence of resistant pathogen populations, so that safer and more environmentally friendly controls are still needed. This study reported the potential of endophytic bacteria from healthy rice plants in inhibiting the growth of R. solani in vitro and their ability to suppress R. solani infection in rice germination. The experiment used a dual culture method between endophytic bacterial strains and R. solani. Observations were made on the growth of R. solani colonies and microscopic mycelium growth. The test was continued by treating the rice seeds using endophytic bacteria. Rice seeds that have been coated with endophytic bacteria were then grown on potato dextrose agar medium that has been overgrown with R. solani. The level of disease blight in seeds showed that almost all of the bacterial strains tested could inhibit the growth of R. solani colonies and also cause malformations in their mycelium. The application of endophytic bacteria to rice seeds also significantly reduced the infection rate of R. solani in rice seeds. Among the bacteria tested, OS7 has the potential to be developed as a biological control agent for rice sheath blight caused by R. solani. Further research on the greenhouse and field scale needs to be done.Rhizoctonia solani merupakan salah satu patogen penting pada tanaman padi yang dapat menyebabkan hawar pada benih, daun, dan pelepah daun. Penyakit hawar pelepah ini menjadi masalah yang cukup serius di berbagai negara penanam padi, termasuk Indonesia. Pengendalian yang mengandalkan penggunaan pestisida sintetis dan varietas tahan sering kali menimbulkan permasalahan baru baik pencemaran lingkungan maupun munculnya populasi patogen resisten sehingga masih diperlukan pengendalian yang lebih aman dan ramah lingkungan. Penelitian ini melaporkan potensi bakteri endofit asal tanaman padi sehat dalam menghambat pertumbuhan R. solani secara in vitro dan kemampunnya dalam menekan infeksi R. solani pada perkecambahan padi. Percobaan menggunakan metode kultur ganda antara galur-galur bakteri endofit dan R. solani. Pengamatan dilakukan terhadap pertumbuhan koloni R. solani dan pertumbuhan miselium secara mikroskopis. Pengujian dilanjutkan dengan memperlakukan benih padi menggunakan bakteri endofit. Benih padi yang telah dilapisi dengan bakteri endofit kemudian ditumbuhkan pada medium agar-agar dekstrosa kentang yang telah ditumbuhi R. solani. Tingkat gangguan penyakit hawar pada benih menunjukkan bahwa hampir semua galur bakteri yang diuji dapat menghambat pertumbuhan koloni R. solani dan juga menyebabkan malformasi pada miseliumnya. Aplikasi bakteri endofit pada benih padi juga secara nyata menurunkan tingkat infeksi R. solani pada benih padi. Di antara bakteri yang diuji, OS7 berpotensi dikembangkan sebagai agens pengendali hayati hawar pelepah yang disebabkan oleh R. solani. Penelitian dalam skala rumah kaca dan skala lapangan perlu dilakukan lebih lanjut